TY  - JOUR
AU  - Milenković, Mila
AU  - Ciasca, Gabriele
AU  - Bonasera, Aurelio
AU  - Scopelliti, Michelangelo
AU  - Marković, Olivera
AU  - Verbić, Tatjana
AU  - Todorović Marković, Biljana
AU  - Jovanović, Svetlana
PY  - 2024
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/6414
AB  - The widespread abuse of traditional antibiotics has led to a global rise in antibiotic-resistant bacteria, which give in return unprecedented health risks. Therefore, there is a large and urgent need for the development of new, smart antibacterial agents able to efficiently kill or inhibit bacterial growth. In this study, we investigated the antibacterial activity of S, N-doped Graphene Quantum Dots (GQDs) as a light-triggered antibacterial agent. Gamma irradiation was employed as a tool to achieve one-step modification of GQDs in the presence of L-cysteine amino acid as a source of heteroatoms. X-ray Photoelectron Spectroscopy (XPS), nuclear magnetic resonance (NMR), and zeta potential measurements provided the necessary data to clarify the structure of modified dots and verify the introduction of both S- and N-atoms in GQDs structure, but also severe changes in the aromatic, sp2 domains. Namely, γ-irradiation caused a bonding of S atoms in 1.14 at.% mainly as thiol groups, and N in 1.81 at.% as amino groups, but sp2 contribution in GQD structure was lowered from 63.00 to 4.86 at.%, as measured in dots irradiated at a dose of 200 kGy. Fluorescence quenching measurements showed that L-cysteine-modified dots are able to bind to human serum albumin. The antibacterial activity of GQDs combined with 1 and 6 h of blue light (470 nm) irradiation was tested against 8 bacterial strains. GQD-cys-25 sample provided the best results, with minimum inhibitory concentration (MIC) as low as 125 μg/mL against S. aureus, E. faecalis, and E. coli after only 1 h of blue light exposure.
PB  - Elsevier
T2  - Journal of Photochemistry and Photobiology B: Biology
T1  - Blue-light-driven photoactivity of L-cysteine-modified graphene quantum dots and their antibacterial effects
VL  - 250
SP  - 112818
DO  - 10.1016/j.jphotobiol.2023.112818
ER  - 

@article{
author = "Milenković, Mila and Ciasca, Gabriele and Bonasera, Aurelio and Scopelliti, Michelangelo and Marković, Olivera and Verbić, Tatjana and Todorović Marković, Biljana and Jovanović, Svetlana",
year = "2024",
abstract = "The widespread abuse of traditional antibiotics has led to a global rise in antibiotic-resistant bacteria, which give in return unprecedented health risks. Therefore, there is a large and urgent need for the development of new, smart antibacterial agents able to efficiently kill or inhibit bacterial growth. In this study, we investigated the antibacterial activity of S, N-doped Graphene Quantum Dots (GQDs) as a light-triggered antibacterial agent. Gamma irradiation was employed as a tool to achieve one-step modification of GQDs in the presence of L-cysteine amino acid as a source of heteroatoms. X-ray Photoelectron Spectroscopy (XPS), nuclear magnetic resonance (NMR), and zeta potential measurements provided the necessary data to clarify the structure of modified dots and verify the introduction of both S- and N-atoms in GQDs structure, but also severe changes in the aromatic, sp2 domains. Namely, γ-irradiation caused a bonding of S atoms in 1.14 at.% mainly as thiol groups, and N in 1.81 at.% as amino groups, but sp2 contribution in GQD structure was lowered from 63.00 to 4.86 at.%, as measured in dots irradiated at a dose of 200 kGy. Fluorescence quenching measurements showed that L-cysteine-modified dots are able to bind to human serum albumin. The antibacterial activity of GQDs combined with 1 and 6 h of blue light (470 nm) irradiation was tested against 8 bacterial strains. GQD-cys-25 sample provided the best results, with minimum inhibitory concentration (MIC) as low as 125 μg/mL against S. aureus, E. faecalis, and E. coli after only 1 h of blue light exposure.",
publisher = "Elsevier",
journal = "Journal of Photochemistry and Photobiology B: Biology",
title = "Blue-light-driven photoactivity of L-cysteine-modified graphene quantum dots and their antibacterial effects",
volume = "250",
pages = "112818",
doi = "10.1016/j.jphotobiol.2023.112818"
}

Milenković, M., Ciasca, G., Bonasera, A., Scopelliti, M., Marković, O., Verbić, T., Todorović Marković, B.,& Jovanović, S.. (2024). Blue-light-driven photoactivity of L-cysteine-modified graphene quantum dots and their antibacterial effects. in Journal of Photochemistry and Photobiology B: Biology
Elsevier., 250, 112818.
https://doi.org/10.1016/j.jphotobiol.2023.112818

Milenković M, Ciasca G, Bonasera A, Scopelliti M, Marković O, Verbić T, Todorović Marković B, Jovanović S. Blue-light-driven photoactivity of L-cysteine-modified graphene quantum dots and their antibacterial effects. in Journal of Photochemistry and Photobiology B: Biology. 2024;250:112818.
doi:10.1016/j.jphotobiol.2023.112818 .

Milenković, Mila, Ciasca, Gabriele, Bonasera, Aurelio, Scopelliti, Michelangelo, Marković, Olivera, Verbić, Tatjana, Todorović Marković, Biljana, Jovanović, Svetlana, "Blue-light-driven photoactivity of L-cysteine-modified graphene quantum dots and their antibacterial effects" in Journal of Photochemistry and Photobiology B: Biology, 250 (2024):112818,
https://doi.org/10.1016/j.jphotobiol.2023.112818 . .

TY  - JOUR
AU  - Milenković, Mila
AU  - Ciasca, Gabriele
AU  - Bonasera, Aurelio
AU  - Scopelliti, Michelangelo
AU  - Marković, Olivera
AU  - Verbić, Tatjana
AU  - Todorović Marković, Biljana
AU  - Jovanović, Svetlana
PY  - 2024
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/6303
AB  - The widespread abuse of traditional antibiotics has led to a global rise in antibiotic-resistant bacteria, which give 
in return unprecedented health risks. Therefore, there is a large and urgent need for the development of new, 
smart antibacterial agents able to efficiently kill or inhibit bacterial growth. In this study, we investigated the 
antibacterial activity of S, N-doped Graphene Quantum Dots (GQDs) as a light-triggered antibacterial agent. 
Gamma irradiation was employed as a tool to achieve one-step modification of GQDs in the presence of L cysteine amino acid as a source of heteroatoms. X-ray Photoelectron Spectroscopy (XPS), nuclear magnetic 
resonance (NMR), and zeta potential measurements provided the necessary data to clarify the structure of 
modified dots and verify the introduction of both S- and N-atoms in GQDs structure, but also severe changes in 
the aromatic, sp2 domains. Namely, γ-irradiation caused a bonding of S atoms in 1.14 at.% mainly as thiol 
groups, and N in 1.81 at.% as amino groups, but sp2 contribution in GQD structure was lowered from 63.00 to 
4.86 at.%, as measured in dots irradiated at a dose of 200 kGy. Fluorescence quenching measurements showed 
that L-cysteine-modified dots are able to bind to human serum albumin. The antibacterial activity of GQDs 
combined with 1 and 6 h of blue light (470 nm) irradiation was tested against 8 bacterial strains. GQD-cys-25 
sample provided the best results, with minimum inhibitory concentration (MIC) as low as 125 μg/mL against 
S. aureus, E. faecalis, and E. coli after only 1 h of blue light exposure.
PB  - Elsevier
T2  - Journal of Photochemistry & Photobiology, B: Biology
T1  - Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects
VL  - 250
SP  - 112818
DO  - 10.1016/j.jphotobiol.2023.112818
ER  - 

@article{
author = "Milenković, Mila and Ciasca, Gabriele and Bonasera, Aurelio and Scopelliti, Michelangelo and Marković, Olivera and Verbić, Tatjana and Todorović Marković, Biljana and Jovanović, Svetlana",
year = "2024",
abstract = "The widespread abuse of traditional antibiotics has led to a global rise in antibiotic-resistant bacteria, which give 
in return unprecedented health risks. Therefore, there is a large and urgent need for the development of new, 
smart antibacterial agents able to efficiently kill or inhibit bacterial growth. In this study, we investigated the 
antibacterial activity of S, N-doped Graphene Quantum Dots (GQDs) as a light-triggered antibacterial agent. 
Gamma irradiation was employed as a tool to achieve one-step modification of GQDs in the presence of L cysteine amino acid as a source of heteroatoms. X-ray Photoelectron Spectroscopy (XPS), nuclear magnetic 
resonance (NMR), and zeta potential measurements provided the necessary data to clarify the structure of 
modified dots and verify the introduction of both S- and N-atoms in GQDs structure, but also severe changes in 
the aromatic, sp2 domains. Namely, γ-irradiation caused a bonding of S atoms in 1.14 at.% mainly as thiol 
groups, and N in 1.81 at.% as amino groups, but sp2 contribution in GQD structure was lowered from 63.00 to 
4.86 at.%, as measured in dots irradiated at a dose of 200 kGy. Fluorescence quenching measurements showed 
that L-cysteine-modified dots are able to bind to human serum albumin. The antibacterial activity of GQDs 
combined with 1 and 6 h of blue light (470 nm) irradiation was tested against 8 bacterial strains. GQD-cys-25 
sample provided the best results, with minimum inhibitory concentration (MIC) as low as 125 μg/mL against 
S. aureus, E. faecalis, and E. coli after only 1 h of blue light exposure.",
publisher = "Elsevier",
journal = "Journal of Photochemistry & Photobiology, B: Biology",
title = "Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects",
volume = "250",
pages = "112818",
doi = "10.1016/j.jphotobiol.2023.112818"
}

Milenković, M., Ciasca, G., Bonasera, A., Scopelliti, M., Marković, O., Verbić, T., Todorović Marković, B.,& Jovanović, S.. (2024). Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects. in Journal of Photochemistry & Photobiology, B: Biology
Elsevier., 250, 112818.
https://doi.org/10.1016/j.jphotobiol.2023.112818

Milenković M, Ciasca G, Bonasera A, Scopelliti M, Marković O, Verbić T, Todorović Marković B, Jovanović S. Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects. in Journal of Photochemistry & Photobiology, B: Biology. 2024;250:112818.
doi:10.1016/j.jphotobiol.2023.112818 .

Milenković, Mila, Ciasca, Gabriele, Bonasera, Aurelio, Scopelliti, Michelangelo, Marković, Olivera, Verbić, Tatjana, Todorović Marković, Biljana, Jovanović, Svetlana, "Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects" in Journal of Photochemistry & Photobiology, B: Biology, 250 (2024):112818,
https://doi.org/10.1016/j.jphotobiol.2023.112818 . .

TY  - CONF
AU  - Verbić, Tatjana
AU  - Avdeef, Alex
AU  - Tam, Kin Y.
AU  - Marković, Olivera S.
AU  - Pešić, Miloš P.
AU  - Topalović, Igor A.
AU  - Veljković, Dušan Ž.
AU  - Kathawala, Mufaddal
AU  - Serajuddin, Abu T. M.
PY  - 2023
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5993
AB  - Since the introduction of combinatorial chemistry and high-throughput screening in drug 
discovery in the early 1990s, the solubility of new chemical entities (NCE) decreased drastically 
while their lipophilicities increased greatly. Characterizing physicochemical properties of low soluble molecules can be especially challenging, since such molecules can undergo 
complicated reactions in aqueous solution, such as forming precipitates or complexes with 
buffer species or undergoing self-aggregation (dimer, trimer, etc.)1,2 or micelle formations. 
Most drugs are ionizable. Foremost to the rational interpretation of solution behavior of 
ionizable drugs in a physiologically-relevant pH domain requires an accurate aqueous pKa, 
determined by a suitable method. In a pH-dependent measurement of a property (e.g. 
solubility-, lipophilicity-, permeability-pH), when the apparent pKa value is different from the 
true aqueous pKa value, it may be an early clue that nonideal solution behavior may be taking 
place. In pharmaceutical research, it may seem cost-effective to use calculated pKa instead of 
measured values, but paradoxically, such preference can lead to inaccurate rationalization of 
the pH-dependent behavior of the drug molecule. For simple molecules, calculated values can 
be useful, but for today’s new drugs or for molecules prone to complicated solution behavior, 
the use of calculated pKas can substantially wrench the interpretation of solution properties. 
Clofazimine (CFZ), although discovered about 66 years ago, and used therapeutically for nearly 
40 years, exhibits some of the properties of relatively recent drug molecules by being 
extremely water insoluble and having variable pKa values reported. We have recently 
combined potentiometric titrations and UV/Vis spectrophotometry in methanol-water 
cosolvent media, accompanied by DFT calculations, to assess the hypothesis of CFZ free base 
dimerization. We reasoned that a soluble dimer might form from drug-drug adhesion along 
the hydrophobic molecular surface. With lessened exposure of the hydrophobic surface to 
water, the dimer would be more water soluble than the monomeric free base. In saturated 
solutions, the apparent solubility in alkaline pH would be elevated due to the presence of the 
dimer. The effect of that would be a lower pKa and reverse pKa cosolvent dependence – the 
behaviour we have noticed in CFZ aqueous solutions. These findings are of paramount 
importance for understanding of CFZ speciation and the future progress in developing its 
improved formulations which is the subject of our ongoing studies.
PB  - International Association of Physical Chemists
C3  - 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK Belgrade, Serbia, September 4-6, 2023
T1  - Revealing the story of an orphan drug: clofazimine speciation  and solubilization as a function of pH
SP  - 15
EP  - 15
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5993
ER  - 

@conference{
author = "Verbić, Tatjana and Avdeef, Alex and Tam, Kin Y. and Marković, Olivera S. and Pešić, Miloš P. and Topalović, Igor A. and Veljković, Dušan Ž. and Kathawala, Mufaddal and Serajuddin, Abu T. M.",
year = "2023",
abstract = "Since the introduction of combinatorial chemistry and high-throughput screening in drug 
discovery in the early 1990s, the solubility of new chemical entities (NCE) decreased drastically 
while their lipophilicities increased greatly. Characterizing physicochemical properties of low soluble molecules can be especially challenging, since such molecules can undergo 
complicated reactions in aqueous solution, such as forming precipitates or complexes with 
buffer species or undergoing self-aggregation (dimer, trimer, etc.)1,2 or micelle formations. 
Most drugs are ionizable. Foremost to the rational interpretation of solution behavior of 
ionizable drugs in a physiologically-relevant pH domain requires an accurate aqueous pKa, 
determined by a suitable method. In a pH-dependent measurement of a property (e.g. 
solubility-, lipophilicity-, permeability-pH), when the apparent pKa value is different from the 
true aqueous pKa value, it may be an early clue that nonideal solution behavior may be taking 
place. In pharmaceutical research, it may seem cost-effective to use calculated pKa instead of 
measured values, but paradoxically, such preference can lead to inaccurate rationalization of 
the pH-dependent behavior of the drug molecule. For simple molecules, calculated values can 
be useful, but for today’s new drugs or for molecules prone to complicated solution behavior, 
the use of calculated pKas can substantially wrench the interpretation of solution properties. 
Clofazimine (CFZ), although discovered about 66 years ago, and used therapeutically for nearly 
40 years, exhibits some of the properties of relatively recent drug molecules by being 
extremely water insoluble and having variable pKa values reported. We have recently 
combined potentiometric titrations and UV/Vis spectrophotometry in methanol-water 
cosolvent media, accompanied by DFT calculations, to assess the hypothesis of CFZ free base 
dimerization. We reasoned that a soluble dimer might form from drug-drug adhesion along 
the hydrophobic molecular surface. With lessened exposure of the hydrophobic surface to 
water, the dimer would be more water soluble than the monomeric free base. In saturated 
solutions, the apparent solubility in alkaline pH would be elevated due to the presence of the 
dimer. The effect of that would be a lower pKa and reverse pKa cosolvent dependence – the 
behaviour we have noticed in CFZ aqueous solutions. These findings are of paramount 
importance for understanding of CFZ speciation and the future progress in developing its 
improved formulations which is the subject of our ongoing studies.",
publisher = "International Association of Physical Chemists",
journal = "10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK Belgrade, Serbia, September 4-6, 2023",
title = "Revealing the story of an orphan drug: clofazimine speciation  and solubilization as a function of pH",
pages = "15-15",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5993"
}

Verbić, T., Avdeef, A., Tam, K. Y., Marković, O. S., Pešić, M. P., Topalović, I. A., Veljković, D. Ž., Kathawala, M.,& Serajuddin, A. T. M.. (2023). Revealing the story of an orphan drug: clofazimine speciation  and solubilization as a function of pH. in 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK Belgrade, Serbia, September 4-6, 2023
International Association of Physical Chemists., 15-15.
https://hdl.handle.net/21.15107/rcub_cherry_5993

Verbić T, Avdeef A, Tam KY, Marković OS, Pešić MP, Topalović IA, Veljković DŽ, Kathawala M, Serajuddin ATM. Revealing the story of an orphan drug: clofazimine speciation  and solubilization as a function of pH. in 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK Belgrade, Serbia, September 4-6, 2023. 2023;:15-15.
https://hdl.handle.net/21.15107/rcub_cherry_5993 .

Verbić, Tatjana, Avdeef, Alex, Tam, Kin Y., Marković, Olivera S., Pešić, Miloš P., Topalović, Igor A., Veljković, Dušan Ž., Kathawala, Mufaddal, Serajuddin, Abu T. M., "Revealing the story of an orphan drug: clofazimine speciation  and solubilization as a function of pH" in 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK Belgrade, Serbia, September 4-6, 2023 (2023):15-15,
https://hdl.handle.net/21.15107/rcub_cherry_5993 .

TY  - CONF
AU  - Topalović, Igor A.
AU  - Marković, Olivera S.
AU  - Pešić, Miloš P.
AU  - Kathawala, Mufaddal
AU  - Serajuddin, Abu T. M.
AU  - Avdeef, Alex
AU  - Verbić, Tatjana
PY  - 2023
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5994
AB  - Methods for drug solubilization have become important part of modern drug discovery and 
development due to increasing number of extremely insoluble drugs and drug candidates. 
One of such methods is acid-base supersolubilization (ABS) [1]. Clofazimine (CFZ) is weakly 
basic antibiotic and anti-inflammatory drug, most notably used in the treatment of leprosy
and tuberculosis, with recently proven inhibitory activity against several coronaviruses [2].
We have recently unraveled its aqueous pKa value and its unique cosolvent dependence [3]. 
The aim of the present study was to investigate CFZ solubilization using the ABS approach. 
Eight small organic acids were tested for the ABS effect (glutaric, malic, tartaric, citric, 
malonic, maleic, succinic, adipic) but only glutaric (GA), malic (MA), and tartaric (TA) acids 
showed some solubilization effect. The effect of their concentration (and the solution pH 
value) was further tested. The solubility of CFZ was determined in GA, MA, and TA solutions 
in wide concentration (1.0×10-2 – 5.0 M) and pH range (~0.2 – 4.8). Equilibration time was 
24 hours (6 h of stirring + 18 h of sedimentation). Phases were separated by filtration. The 
CFZ concentration in supernatant was determined by HPLC-UV/VIS. Results show that CFZ 
solubility increases as acid concentration increases: from 3.04×10-3 to 10.68 mg/mL (in GA), 
from 9.06×10-3 to 1.23 mg/mL (in MA) and from 4.76×10-3 to 0.32 mg/mL (in TA). The effect 
of CFZ solubilization is much more pronounced when the acid concentration is raised above 
2 M. These results can be used as the basis for further CFZ formulation optimization.
Furthermore, our ongoing research is focused on the type of interactions and other possible 
factors that can influence CFZ and other prectically insoluble drugs, embracing (super)solu bilization as a general methodology in drug design and development.
PB  - International Association of Physical Chemists
C3  - 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK Belgrade, Serbia, September 4-6, 2023
T1  - Clofazimine acid-base solubilization: influence  of small organic acids’ concentration
SP  - 66
EP  - 66
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5994
ER  - 

@conference{
author = "Topalović, Igor A. and Marković, Olivera S. and Pešić, Miloš P. and Kathawala, Mufaddal and Serajuddin, Abu T. M. and Avdeef, Alex and Verbić, Tatjana",
year = "2023",
abstract = "Methods for drug solubilization have become important part of modern drug discovery and 
development due to increasing number of extremely insoluble drugs and drug candidates. 
One of such methods is acid-base supersolubilization (ABS) [1]. Clofazimine (CFZ) is weakly 
basic antibiotic and anti-inflammatory drug, most notably used in the treatment of leprosy
and tuberculosis, with recently proven inhibitory activity against several coronaviruses [2].
We have recently unraveled its aqueous pKa value and its unique cosolvent dependence [3]. 
The aim of the present study was to investigate CFZ solubilization using the ABS approach. 
Eight small organic acids were tested for the ABS effect (glutaric, malic, tartaric, citric, 
malonic, maleic, succinic, adipic) but only glutaric (GA), malic (MA), and tartaric (TA) acids 
showed some solubilization effect. The effect of their concentration (and the solution pH 
value) was further tested. The solubility of CFZ was determined in GA, MA, and TA solutions 
in wide concentration (1.0×10-2 – 5.0 M) and pH range (~0.2 – 4.8). Equilibration time was 
24 hours (6 h of stirring + 18 h of sedimentation). Phases were separated by filtration. The 
CFZ concentration in supernatant was determined by HPLC-UV/VIS. Results show that CFZ 
solubility increases as acid concentration increases: from 3.04×10-3 to 10.68 mg/mL (in GA), 
from 9.06×10-3 to 1.23 mg/mL (in MA) and from 4.76×10-3 to 0.32 mg/mL (in TA). The effect 
of CFZ solubilization is much more pronounced when the acid concentration is raised above 
2 M. These results can be used as the basis for further CFZ formulation optimization.
Furthermore, our ongoing research is focused on the type of interactions and other possible 
factors that can influence CFZ and other prectically insoluble drugs, embracing (super)solu bilization as a general methodology in drug design and development.",
publisher = "International Association of Physical Chemists",
journal = "10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK Belgrade, Serbia, September 4-6, 2023",
title = "Clofazimine acid-base solubilization: influence  of small organic acids’ concentration",
pages = "66-66",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5994"
}

Topalović, I. A., Marković, O. S., Pešić, M. P., Kathawala, M., Serajuddin, A. T. M., Avdeef, A.,& Verbić, T.. (2023). Clofazimine acid-base solubilization: influence  of small organic acids’ concentration. in 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK Belgrade, Serbia, September 4-6, 2023
International Association of Physical Chemists., 66-66.
https://hdl.handle.net/21.15107/rcub_cherry_5994

Topalović IA, Marković OS, Pešić MP, Kathawala M, Serajuddin ATM, Avdeef A, Verbić T. Clofazimine acid-base solubilization: influence  of small organic acids’ concentration. in 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK Belgrade, Serbia, September 4-6, 2023. 2023;:66-66.
https://hdl.handle.net/21.15107/rcub_cherry_5994 .

Topalović, Igor A., Marković, Olivera S., Pešić, Miloš P., Kathawala, Mufaddal, Serajuddin, Abu T. M., Avdeef, Alex, Verbić, Tatjana, "Clofazimine acid-base solubilization: influence  of small organic acids’ concentration" in 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK Belgrade, Serbia, September 4-6, 2023 (2023):66-66,
https://hdl.handle.net/21.15107/rcub_cherry_5994 .

TY  - JOUR
AU  - Marković, Olivera S.
AU  - Patel, Nirali G.
AU  - Serajuddin, Abu T. M.
AU  - Avdeef, Alex
AU  - Verbić, Tatjana
PY  - 2022
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5039
AB  - The solubility of a model basic drug, nortriptyline
(Nor), was investigated as a function of pH in phosphate and/or a
chloride-containing aqueous suspension using experimental
practices recommended in the previously published “white
paper” (Avdeef et al., 2016). The pH-Ramp Shake-Flask (pHRSF) method, introduced in our earlier work (Marković et al.,
2019), was applied. An improved and more detailed experimental
design of the Nor solubility measurement allowed us to exploit the
full capacity of the pH-RSF method. Complex equilibria in the
aqueous phase (cationic and anionic complex formation between
Nor and the phosphate) and solid-phase transformations (Nor free
base, 1:1 Nor hydrochloride salt, 1:1 and 1:2 Nor phosphate salts)
were characterized by a detailed analysis of the solubility
measurements using the computer program pDISOL-X. The solid phases were characterized by thermogravimetric analysis,
differential scanning calorimetry, powder X-ray diffraction, and elemental analyses. The results of the present investigation illustrate
the influence of competing counterions, such as buffering agents, complexing agents, salt coformers, tonicity adjusters, and so forth,
on the aqueous solubility of drugs and interconversion of salts. Careful attention given to these factors can be helpful in the
formulation of drug products.
PB  - American Chemical Society
T2  - Molecular pharmaceutics
T1  - Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints
VL  - 19
IS  - 2
SP  - 710
EP  - 719
DO  - 10.1021/acs.molpharmaceut.1c00919
ER  - 

@article{
author = "Marković, Olivera S. and Patel, Nirali G. and Serajuddin, Abu T. M. and Avdeef, Alex and Verbić, Tatjana",
year = "2022",
abstract = "The solubility of a model basic drug, nortriptyline
(Nor), was investigated as a function of pH in phosphate and/or a
chloride-containing aqueous suspension using experimental
practices recommended in the previously published “white
paper” (Avdeef et al., 2016). The pH-Ramp Shake-Flask (pHRSF) method, introduced in our earlier work (Marković et al.,
2019), was applied. An improved and more detailed experimental
design of the Nor solubility measurement allowed us to exploit the
full capacity of the pH-RSF method. Complex equilibria in the
aqueous phase (cationic and anionic complex formation between
Nor and the phosphate) and solid-phase transformations (Nor free
base, 1:1 Nor hydrochloride salt, 1:1 and 1:2 Nor phosphate salts)
were characterized by a detailed analysis of the solubility
measurements using the computer program pDISOL-X. The solid phases were characterized by thermogravimetric analysis,
differential scanning calorimetry, powder X-ray diffraction, and elemental analyses. The results of the present investigation illustrate
the influence of competing counterions, such as buffering agents, complexing agents, salt coformers, tonicity adjusters, and so forth,
on the aqueous solubility of drugs and interconversion of salts. Careful attention given to these factors can be helpful in the
formulation of drug products.",
publisher = "American Chemical Society",
journal = "Molecular pharmaceutics",
title = "Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints",
volume = "19",
number = "2",
pages = "710-719",
doi = "10.1021/acs.molpharmaceut.1c00919"
}

Marković, O. S., Patel, N. G., Serajuddin, A. T. M., Avdeef, A.,& Verbić, T.. (2022). Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints. in Molecular pharmaceutics
American Chemical Society., 19(2), 710-719.
https://doi.org/10.1021/acs.molpharmaceut.1c00919

Marković OS, Patel NG, Serajuddin ATM, Avdeef A, Verbić T. Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints. in Molecular pharmaceutics. 2022;19(2):710-719.
doi:10.1021/acs.molpharmaceut.1c00919 .

Marković, Olivera S., Patel, Nirali G., Serajuddin, Abu T. M., Avdeef, Alex, Verbić, Tatjana, "Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints" in Molecular pharmaceutics, 19, no. 2 (2022):710-719,
https://doi.org/10.1021/acs.molpharmaceut.1c00919 . .

TY  - JOUR
AU  - Dorontic, Sladjana
AU  - Bonasera, Aurelio
AU  - Scopelliti, Michelangelo
AU  - Marković, Olivera S.
AU  - Bajuk Bogdanović, Danica
AU  - Ciasca, Gabriele
AU  - Romanò, Sabrina
AU  - Dimkić, Ivica
AU  - Budimir, Milica
AU  - Marinković, Dragana
AU  - Jovanovic, Svetlana
PY  - 2022
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5883
AB  - Structural modification of different carbon-based nanomaterials is often necessary to
improve their morphology and optical properties, particularly the incorporation of N-atoms in
graphene quantum dots (GQDs). Here, a clean, simple, one-step, and eco-friendly method for
N-doping of GQDs using gamma irradiation is reported. GQDs were irradiated in the presence
of the different ethylenediamine (EDA) amounts (1 g, 5 g, and 10 g) and the highest % of N was
detected in the presence of 10 g. N-doped GQDs emitted strong, blue photoluminescence (PL).
Photoluminescence quantum yield was increased from 1.45, as obtained for non-irradiated dots,
to 7.24% for those irradiated in the presence of 1 g of EDA. Modified GQDs were investigated as
a PL probe for the detection of insecticide Carbofuran (2,2-Dimethyl-2,3-dihydro-1-benzofuran-7-
yl methylcarbamate) and herbicide Amitrole (3-amino-1,2,4-triazole). The limit of detection was
5.4 µmol L−1
for Carbofuran. For the first time, Amitrole was detected by GQDs in a turn-off/turn-on
mechanism using Pd(II) ions as a quenching agent. First, Pd(II) ions were quenched (turn-off) PL
of GQDs, while after Amitrole addition, PL was recovered linearly with Amitrole concentration
(turn-on). LOD was 2.03 µmol L−1
. These results suggest that modified GQDs can be used as an
efficient new material for Carbofuran and Amitrole detection. Furthermore, the phototoxicity of dots
was investigated on both Gram-positive and Gram-negative bacterial strains. When bacterial cells
were exposed to different GQD concentrations and illuminated with light of 470 nm wavelength, the
toxic effects were not observed.
PB  - MDPI
T2  - Nanomaterials
T1  - Gamma-ray-induced structural transformation of GQDs  towards the improvement of their optical properties, monitoring of selected toxic compounds,  and photo-induced effect on bacterial strains
VL  - 12
SP  - 2714
DO  - https://doi.org/10.3390/nano12152714
ER  - 

@article{
author = "Dorontic, Sladjana and Bonasera, Aurelio and Scopelliti, Michelangelo and Marković, Olivera S. and Bajuk Bogdanović, Danica and Ciasca, Gabriele and Romanò, Sabrina and Dimkić, Ivica and Budimir, Milica and Marinković, Dragana and Jovanovic, Svetlana",
year = "2022",
abstract = "Structural modification of different carbon-based nanomaterials is often necessary to
improve their morphology and optical properties, particularly the incorporation of N-atoms in
graphene quantum dots (GQDs). Here, a clean, simple, one-step, and eco-friendly method for
N-doping of GQDs using gamma irradiation is reported. GQDs were irradiated in the presence
of the different ethylenediamine (EDA) amounts (1 g, 5 g, and 10 g) and the highest % of N was
detected in the presence of 10 g. N-doped GQDs emitted strong, blue photoluminescence (PL).
Photoluminescence quantum yield was increased from 1.45, as obtained for non-irradiated dots,
to 7.24% for those irradiated in the presence of 1 g of EDA. Modified GQDs were investigated as
a PL probe for the detection of insecticide Carbofuran (2,2-Dimethyl-2,3-dihydro-1-benzofuran-7-
yl methylcarbamate) and herbicide Amitrole (3-amino-1,2,4-triazole). The limit of detection was
5.4 µmol L−1
for Carbofuran. For the first time, Amitrole was detected by GQDs in a turn-off/turn-on
mechanism using Pd(II) ions as a quenching agent. First, Pd(II) ions were quenched (turn-off) PL
of GQDs, while after Amitrole addition, PL was recovered linearly with Amitrole concentration
(turn-on). LOD was 2.03 µmol L−1
. These results suggest that modified GQDs can be used as an
efficient new material for Carbofuran and Amitrole detection. Furthermore, the phototoxicity of dots
was investigated on both Gram-positive and Gram-negative bacterial strains. When bacterial cells
were exposed to different GQD concentrations and illuminated with light of 470 nm wavelength, the
toxic effects were not observed.",
publisher = "MDPI",
journal = "Nanomaterials",
title = "Gamma-ray-induced structural transformation of GQDs  towards the improvement of their optical properties, monitoring of selected toxic compounds,  and photo-induced effect on bacterial strains",
volume = "12",
pages = "2714",
doi = "https://doi.org/10.3390/nano12152714"
}

Dorontic, S., Bonasera, A., Scopelliti, M., Marković, O. S., Bajuk Bogdanović, D., Ciasca, G., Romanò, S., Dimkić, I., Budimir, M., Marinković, D.,& Jovanovic, S.. (2022). Gamma-ray-induced structural transformation of GQDs  towards the improvement of their optical properties, monitoring of selected toxic compounds,  and photo-induced effect on bacterial strains. in Nanomaterials
MDPI., 12, 2714.
https://doi.org/https://doi.org/10.3390/nano12152714

Dorontic S, Bonasera A, Scopelliti M, Marković OS, Bajuk Bogdanović D, Ciasca G, Romanò S, Dimkić I, Budimir M, Marinković D, Jovanovic S. Gamma-ray-induced structural transformation of GQDs  towards the improvement of their optical properties, monitoring of selected toxic compounds,  and photo-induced effect on bacterial strains. in Nanomaterials. 2022;12:2714.
doi:https://doi.org/10.3390/nano12152714 .

Dorontic, Sladjana, Bonasera, Aurelio, Scopelliti, Michelangelo, Marković, Olivera S., Bajuk Bogdanović, Danica, Ciasca, Gabriele, Romanò, Sabrina, Dimkić, Ivica, Budimir, Milica, Marinković, Dragana, Jovanovic, Svetlana, "Gamma-ray-induced structural transformation of GQDs  towards the improvement of their optical properties, monitoring of selected toxic compounds,  and photo-induced effect on bacterial strains" in Nanomaterials, 12 (2022):2714,
https://doi.org/https://doi.org/10.3390/nano12152714 . .

TY  - JOUR
AU  - Dorontic, Sladjana
AU  - Bonasera, Aurelio
AU  - Scopelliti, Michelangelo
AU  - Mojsin, Marija
AU  - Stevanovic, Milena
AU  - Marković, Olivera S.
AU  - Jovanović, Svetlana
PY  - 2022
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5935
AB  - Large amounts of hazardous and toxic substances in the environment require non-toxic, cheap, easy, rapid, and 
sensitive methods for their detection. Blue luminescent graphene quantum dots (GQDs) were produced by 
electrochemical cleavage of graphite electrodes followed by gamma irradiation in the presence of ethylenedi amine (EDA). Modified dots were able to detect metal ions (Co2+, Pd2+, Fe3+) due to photoluminescence 
quenching. The highest sensitivity was detected for the sample irradiated at a dose of 25 kGy. The limits of 
detection (LODs) were 1.79, 2.55, and 0.66 μmol L− 1 for Co2+, Fe3+, and Pd2+, respectively. It was observed that 
GQDs irradiated at 200 kGy act as an ultra-sensitive turn-on probe for Malathion detection with LOD of 94 nmol 
L− 1
. Atomic force microscopy images proved the aggregation of GQDs in the presence of the investigated metal 
ions. Results obtained by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and LIVE/ 
DEAD cytotoxicity test indicated that GQDs irradiated with EDA are not toxic towards MRC-5 cells, which makes 
them a promising, eco-friendly and safe material for sensing application.
PB  - Elsevier
T2  - Journal of Luminescence
T1  - Blue luminescent amino-functionalized  graphene quantum dots as a responsive material for potential detection of metal ions and  malathion
VL  - 252
SP  - 119311
DO  - 10.1016/j.jlumin.2022.119311
ER  - 

@article{
author = "Dorontic, Sladjana and Bonasera, Aurelio and Scopelliti, Michelangelo and Mojsin, Marija and Stevanovic, Milena and Marković, Olivera S. and Jovanović, Svetlana",
year = "2022",
abstract = "Large amounts of hazardous and toxic substances in the environment require non-toxic, cheap, easy, rapid, and 
sensitive methods for their detection. Blue luminescent graphene quantum dots (GQDs) were produced by 
electrochemical cleavage of graphite electrodes followed by gamma irradiation in the presence of ethylenedi amine (EDA). Modified dots were able to detect metal ions (Co2+, Pd2+, Fe3+) due to photoluminescence 
quenching. The highest sensitivity was detected for the sample irradiated at a dose of 25 kGy. The limits of 
detection (LODs) were 1.79, 2.55, and 0.66 μmol L− 1 for Co2+, Fe3+, and Pd2+, respectively. It was observed that 
GQDs irradiated at 200 kGy act as an ultra-sensitive turn-on probe for Malathion detection with LOD of 94 nmol 
L− 1
. Atomic force microscopy images proved the aggregation of GQDs in the presence of the investigated metal 
ions. Results obtained by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and LIVE/ 
DEAD cytotoxicity test indicated that GQDs irradiated with EDA are not toxic towards MRC-5 cells, which makes 
them a promising, eco-friendly and safe material for sensing application.",
publisher = "Elsevier",
journal = "Journal of Luminescence",
title = "Blue luminescent amino-functionalized  graphene quantum dots as a responsive material for potential detection of metal ions and  malathion",
volume = "252",
pages = "119311",
doi = "10.1016/j.jlumin.2022.119311"
}

Dorontic, S., Bonasera, A., Scopelliti, M., Mojsin, M., Stevanovic, M., Marković, O. S.,& Jovanović, S.. (2022). Blue luminescent amino-functionalized  graphene quantum dots as a responsive material for potential detection of metal ions and  malathion. in Journal of Luminescence
Elsevier., 252, 119311.
https://doi.org/10.1016/j.jlumin.2022.119311

Dorontic S, Bonasera A, Scopelliti M, Mojsin M, Stevanovic M, Marković OS, Jovanović S. Blue luminescent amino-functionalized  graphene quantum dots as a responsive material for potential detection of metal ions and  malathion. in Journal of Luminescence. 2022;252:119311.
doi:10.1016/j.jlumin.2022.119311 .

Dorontic, Sladjana, Bonasera, Aurelio, Scopelliti, Michelangelo, Mojsin, Marija, Stevanovic, Milena, Marković, Olivera S., Jovanović, Svetlana, "Blue luminescent amino-functionalized  graphene quantum dots as a responsive material for potential detection of metal ions and  malathion" in Journal of Luminescence, 252 (2022):119311,
https://doi.org/10.1016/j.jlumin.2022.119311 . .

TY  - CONF
AU  - Marković, Olivera S.
AU  - Gajić, Brankica P.
AU  - Pešić, Miloš P.
AU  - Verbić, Tatjana
PY  - 2022
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5936
AB  - Experimental studies of solubility are important in all phases of drug design and 
development. Solubility data are used to screen out drug-like candidates, 
biopharmaceutical classification and formulation optimization. The development of oral 
and parenteral dosage forms can be challenging, especially when drugs are poorly 
soluble, ionizable, exhibiting pH-dependent solubility and when multiple counterions 
are present in drug suspension. The influence of different counterions on the existing 
equilibria and on pH-dependent drug solubility must be defined in such systems. To 
investigate the effect of multiple ions on the solubility of a model basic drug – tricyclic 
antidepressant imipramine (Im), we conducted a systematic study of the Im solubility as 
a function of pH in the presence of both chloride and phosphate ions as well as in 
chloride-free and phosphate-free suspensions. The pH–Ramp shake–flask method1,2 was 
used for solubility determination. The computer program pDISOL–X was used for data 
analysis. It is shown that distinct pH-dependent solubility profiles were obtained in 
studied systems. Depending on the pH and the total concentration of chloride and/or 
phosphate ions, Im can precipitate as chloride and phosphate salt or free base. 
Furthermore, pH values of solid phase transitions (pHmax) varied as well. For instance, 
pHmax of solid phase transition of (ImH)H2PO4(s) to (ImH)2HPO4(s) change from 5.15 
(chloride and phosphate-containing suspensions) to 5.73 (chloride-free suspensions). 
The intensive self-aggregation of Im in acidic region was suppressed by raising chloride 
or phosphate ions concentration (Iavg 1.42–1.64 M). In that way, solubility of Im was 
decreased due to the common-ion effect. This study illustrates the influence of 
competing counterions on Im solubility and on interconversions in solid phase. Hence, 
such factors must be taken into account during formulation optimization in drug 
research.
PB  - Belgrade : Serbian Chemical Society
PB  - Belgrade : Serbian Young Chemists’ Club
C3  - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts
T1  - The influence of  competing counterions on the solubility of imipramine
SP  - 27
EP  - 27
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5936
ER  - 

@conference{
author = "Marković, Olivera S. and Gajić, Brankica P. and Pešić, Miloš P. and Verbić, Tatjana",
year = "2022",
abstract = "Experimental studies of solubility are important in all phases of drug design and 
development. Solubility data are used to screen out drug-like candidates, 
biopharmaceutical classification and formulation optimization. The development of oral 
and parenteral dosage forms can be challenging, especially when drugs are poorly 
soluble, ionizable, exhibiting pH-dependent solubility and when multiple counterions 
are present in drug suspension. The influence of different counterions on the existing 
equilibria and on pH-dependent drug solubility must be defined in such systems. To 
investigate the effect of multiple ions on the solubility of a model basic drug – tricyclic 
antidepressant imipramine (Im), we conducted a systematic study of the Im solubility as 
a function of pH in the presence of both chloride and phosphate ions as well as in 
chloride-free and phosphate-free suspensions. The pH–Ramp shake–flask method1,2 was 
used for solubility determination. The computer program pDISOL–X was used for data 
analysis. It is shown that distinct pH-dependent solubility profiles were obtained in 
studied systems. Depending on the pH and the total concentration of chloride and/or 
phosphate ions, Im can precipitate as chloride and phosphate salt or free base. 
Furthermore, pH values of solid phase transitions (pHmax) varied as well. For instance, 
pHmax of solid phase transition of (ImH)H2PO4(s) to (ImH)2HPO4(s) change from 5.15 
(chloride and phosphate-containing suspensions) to 5.73 (chloride-free suspensions). 
The intensive self-aggregation of Im in acidic region was suppressed by raising chloride 
or phosphate ions concentration (Iavg 1.42–1.64 M). In that way, solubility of Im was 
decreased due to the common-ion effect. This study illustrates the influence of 
competing counterions on Im solubility and on interconversions in solid phase. Hence, 
such factors must be taken into account during formulation optimization in drug 
research.",
publisher = "Belgrade : Serbian Chemical Society, Belgrade : Serbian Young Chemists’ Club",
journal = "8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts",
title = "The influence of  competing counterions on the solubility of imipramine",
pages = "27-27",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5936"
}

Marković, O. S., Gajić, B. P., Pešić, M. P.,& Verbić, T.. (2022). The influence of  competing counterions on the solubility of imipramine. in 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts
Belgrade : Serbian Chemical Society., 27-27.
https://hdl.handle.net/21.15107/rcub_cherry_5936

Marković OS, Gajić BP, Pešić MP, Verbić T. The influence of  competing counterions on the solubility of imipramine. in 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts. 2022;:27-27.
https://hdl.handle.net/21.15107/rcub_cherry_5936 .

Marković, Olivera S., Gajić, Brankica P., Pešić, Miloš P., Verbić, Tatjana, "The influence of  competing counterions on the solubility of imipramine" in 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts (2022):27-27,
https://hdl.handle.net/21.15107/rcub_cherry_5936 .

TY  - CONF
AU  - Topalović, Igor A.
AU  - Marković, Olivera S.
AU  - Pešić, Miloš P.
AU  - Verbić, Tatjana
PY  - 2022
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5937
AB  - Nowadays, more than two-thirds of potential drugs currently being discovered are 
practically insoluble in water with solubility <100 μg/mL. Despite that, compounds with 
even lower solubility (<0.1 μg/mL) are commonly selected for further development 
which is very challenging, especially in the pharmaceutical formulation process1
. 
Clofazimine (CFZ), an anti-leprosy drug with inhibitory activity against several 
coronaviruses, has a favourable safety profile2
, but it is poorly soluble in aqueous media. 
Hence, it is important to develop a method for increasing its solubility. In this work, a 
relatively novel approach of enhancing solubility of weakly basic drugs by using weak 
acids that would not form salts with the drug (acid-base supersolubilization (ABS)) has
been applied. CFZ aqueous solubility was determined in solutions of tartaric, citric, 
malic, malonic or maleic acid: in set I acid solutions had the same concentration (2.5 
mol/L), and in the set II they were scaled to the same pH (1.0). The drug was added in 
stirred acid solution until a precipitate was noticed and, after filtration, CFZ 
concentration in samples was determined by HPLC. Based on set I, it was found that the 
solubility of CFZ had the highest value in the case of tartaric acid (0.46 mg/mL) 
compared to other acid solutions of the same concentration. In set II the highest CFZ 
concentration was determined in the malic acid solution which had the highest 
concentration (2.8 mol/L) among other acids. On contrary, maleic acid solution at 
pH=1.0 had the lowest molar concentration (0.5 mol/L) and therefore CFZ was 
minimally dissolved. Further research will be directed toward the examination of acid 
structure effect on CFZ solubility.
PB  - Belgrade : Serbian Chemical Society
PB  - Belgrade : Serbian Young Chemists’ Club
C3  - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts
T1  - Investigation of  clofazimine acid-base supersolubilization using various weak organic acids
SP  - 37
EP  - 37
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5937
ER  - 

@conference{
author = "Topalović, Igor A. and Marković, Olivera S. and Pešić, Miloš P. and Verbić, Tatjana",
year = "2022",
abstract = "Nowadays, more than two-thirds of potential drugs currently being discovered are 
practically insoluble in water with solubility <100 μg/mL. Despite that, compounds with 
even lower solubility (<0.1 μg/mL) are commonly selected for further development 
which is very challenging, especially in the pharmaceutical formulation process1
. 
Clofazimine (CFZ), an anti-leprosy drug with inhibitory activity against several 
coronaviruses, has a favourable safety profile2
, but it is poorly soluble in aqueous media. 
Hence, it is important to develop a method for increasing its solubility. In this work, a 
relatively novel approach of enhancing solubility of weakly basic drugs by using weak 
acids that would not form salts with the drug (acid-base supersolubilization (ABS)) has
been applied. CFZ aqueous solubility was determined in solutions of tartaric, citric, 
malic, malonic or maleic acid: in set I acid solutions had the same concentration (2.5 
mol/L), and in the set II they were scaled to the same pH (1.0). The drug was added in 
stirred acid solution until a precipitate was noticed and, after filtration, CFZ 
concentration in samples was determined by HPLC. Based on set I, it was found that the 
solubility of CFZ had the highest value in the case of tartaric acid (0.46 mg/mL) 
compared to other acid solutions of the same concentration. In set II the highest CFZ 
concentration was determined in the malic acid solution which had the highest 
concentration (2.8 mol/L) among other acids. On contrary, maleic acid solution at 
pH=1.0 had the lowest molar concentration (0.5 mol/L) and therefore CFZ was 
minimally dissolved. Further research will be directed toward the examination of acid 
structure effect on CFZ solubility.",
publisher = "Belgrade : Serbian Chemical Society, Belgrade : Serbian Young Chemists’ Club",
journal = "8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts",
title = "Investigation of  clofazimine acid-base supersolubilization using various weak organic acids",
pages = "37-37",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5937"
}

Topalović, I. A., Marković, O. S., Pešić, M. P.,& Verbić, T.. (2022). Investigation of  clofazimine acid-base supersolubilization using various weak organic acids. in 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts
Belgrade : Serbian Chemical Society., 37-37.
https://hdl.handle.net/21.15107/rcub_cherry_5937

Topalović IA, Marković OS, Pešić MP, Verbić T. Investigation of  clofazimine acid-base supersolubilization using various weak organic acids. in 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts. 2022;:37-37.
https://hdl.handle.net/21.15107/rcub_cherry_5937 .

Topalović, Igor A., Marković, Olivera S., Pešić, Miloš P., Verbić, Tatjana, "Investigation of  clofazimine acid-base supersolubilization using various weak organic acids" in 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts (2022):37-37,
https://hdl.handle.net/21.15107/rcub_cherry_5937 .

TY  - CONF
AU  - Marjanović, Nemanja Ž.
AU  - Marković, Olivera S.
AU  - Pešić, Miloš P.
AU  - Verbić, Tatjana
PY  - 2022
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5938
AB  - In the modern drug research the number of practically insoluble potential drugs is 
increasing. Poor aqueous solubility can cause poor oral absorption and low 
bioavailability of drugs. Hence, solubility enhancement is considered as one of the most 
important challenges in the formulation and development of the dosage forms of drugs. 
Clofazimine (CFZ) is an antibiotic drug which is used in the treatment of tuberculosis 
and leprosy. It is recently shown that CFZ has inhibitory activity against certain 
coronaviruses and can antagonize the replication of SARS-CoV-2.1 Since CFZ is highly 
lipophilic molecule with extremely low solubility, it is quite a challenge to find 
appropriate method for CFZ solubilization. The aim of this work was to investigate the 
effect of methanesulfonic (MSA) and glutaric (GA) acids on the solubility of CFZ. The 
effect of MSA on the solubility of CFZ was studied by the pH-Ramp shake-flask method 
(pH-RSF).2 The solubility of CFZ was determined in the presence of GA in two ways: 
1) by melting a mixture of CFZ and GA in different molar ratios, and then dissolving in 
water; 2) using the pH-RSF method. Interactions between CZ and GA were investigated 
by IR spectroscopy. It is shown that both MSA and GA increase the solubility of CFZ 
in acidic suspensions prepared by pH-RSF method. Also, solubility enhancement was 
observed in the molten CFZ-GA mixtures (molar ratio 1:1 and 1:4) compared to mixtures 
prepared without melting. Besides that, the IR spectra of these mixtures revealed that 
characteristic CFZ band was shifted in molted CFZ-GA mixture (molar ratio 1:1) 
probably due to CFZ-GA interactions. Preliminary results presented in this study 
illustrate that MSA and GA can be used for solubility improvement of CFZ.
PB  - Belgrade : Serbian Chemical Society
PB  - Belgrade : Serbian Young Chemists’ Club
C3  - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts
T1  - The effect  of methanesulfonic and glutaric acids on the solubility of clofazimine
SP  - 40
EP  - 40
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5938
ER  - 

@conference{
author = "Marjanović, Nemanja Ž. and Marković, Olivera S. and Pešić, Miloš P. and Verbić, Tatjana",
year = "2022",
abstract = "In the modern drug research the number of practically insoluble potential drugs is 
increasing. Poor aqueous solubility can cause poor oral absorption and low 
bioavailability of drugs. Hence, solubility enhancement is considered as one of the most 
important challenges in the formulation and development of the dosage forms of drugs. 
Clofazimine (CFZ) is an antibiotic drug which is used in the treatment of tuberculosis 
and leprosy. It is recently shown that CFZ has inhibitory activity against certain 
coronaviruses and can antagonize the replication of SARS-CoV-2.1 Since CFZ is highly 
lipophilic molecule with extremely low solubility, it is quite a challenge to find 
appropriate method for CFZ solubilization. The aim of this work was to investigate the 
effect of methanesulfonic (MSA) and glutaric (GA) acids on the solubility of CFZ. The 
effect of MSA on the solubility of CFZ was studied by the pH-Ramp shake-flask method 
(pH-RSF).2 The solubility of CFZ was determined in the presence of GA in two ways: 
1) by melting a mixture of CFZ and GA in different molar ratios, and then dissolving in 
water; 2) using the pH-RSF method. Interactions between CZ and GA were investigated 
by IR spectroscopy. It is shown that both MSA and GA increase the solubility of CFZ 
in acidic suspensions prepared by pH-RSF method. Also, solubility enhancement was 
observed in the molten CFZ-GA mixtures (molar ratio 1:1 and 1:4) compared to mixtures 
prepared without melting. Besides that, the IR spectra of these mixtures revealed that 
characteristic CFZ band was shifted in molted CFZ-GA mixture (molar ratio 1:1) 
probably due to CFZ-GA interactions. Preliminary results presented in this study 
illustrate that MSA and GA can be used for solubility improvement of CFZ.",
publisher = "Belgrade : Serbian Chemical Society, Belgrade : Serbian Young Chemists’ Club",
journal = "8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts",
title = "The effect  of methanesulfonic and glutaric acids on the solubility of clofazimine",
pages = "40-40",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5938"
}

Marjanović, N. Ž., Marković, O. S., Pešić, M. P.,& Verbić, T.. (2022). The effect  of methanesulfonic and glutaric acids on the solubility of clofazimine. in 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts
Belgrade : Serbian Chemical Society., 40-40.
https://hdl.handle.net/21.15107/rcub_cherry_5938

Marjanović NŽ, Marković OS, Pešić MP, Verbić T. The effect  of methanesulfonic and glutaric acids on the solubility of clofazimine. in 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts. 2022;:40-40.
https://hdl.handle.net/21.15107/rcub_cherry_5938 .

Marjanović, Nemanja Ž., Marković, Olivera S., Pešić, Miloš P., Verbić, Tatjana, "The effect  of methanesulfonic and glutaric acids on the solubility of clofazimine" in 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts (2022):40-40,
https://hdl.handle.net/21.15107/rcub_cherry_5938 .

TY  - CONF
AU  - Mrđinac, Jelena Ž.
AU  - Marković, Olivera S.
AU  - Pešić, Miloš P.
AU  - Verbić, Tatjana
PY  - 2022
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5939
AB  - The ionization constant (usually expressed in logarithmic form, pKa) is important 
physicochemical parameter which is used to characterize the acid-base chemistry of a 
compound. Since most drugs contain one or more ionizable functional groups, 
knowledge of pKa values is necessary in drug research. The most common techniques 
used for pKa determination are potentiometry and spectrophotometry. Potentiometry is 
a method of choice when ionization processes are overlapping, as in such case it is not 
possible to obtain the absorption spectrum of each species present in solution. The aim 
of this work was the comparative analysis of pKa determination using potentiometry and 
spectrophotometry for model compounds with overlapping ionization processes: 3-
aminobenzoic acid, 1,3,5-benzenetricarboxylic acid and tyrosine. The potentiometric
titrations were performed with pSOL Model 3 instrument (pION) equipped with pS 
software package for titration data analysis.1 Avdeef–Bucher four–parameter equation 
was used for electrode standardization.2 To overcome the above-mentioned limitation of 
spectrophotometry, the alternative approach was applied in this study. The new 
aminocaproate phosphate buffer (containing phosphoric and ε-aminocaproic acids) was 
used for the solutions preparation of the model compounds in pH range 1 – 12. This 
buffer has numerous advantages like UV-transparency, resistance to pH changes upon 
standing for several days, useful buffer capacity and constant ionic strength in the wide 
range of pH values. Absorption spectra were recorded according to specific procedure 
which was carefully designed to avoid systematic errors. Collected absorption spectra 
will be used for the development of the algorithm for the spectral deconvolution (using 
MATLAB). Such software can be very useful tool in the drug research, especially for 
the analysis of the compounds which pKa values cannot be determined by potentiometry.
PB  - Belgrade : Serbian Chemical Society
PB  - Belgrade : Serbian Young Chemists’ Club
C3  - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts
T1  - Comparative  analysis of ionization constants determination using spectrophotometry and potentiometry: 3- aminobenzoic acid, 1,3,5-benzenetricarboxylic acid and tyrosine
SP  - 42
EP  - 42
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5939
ER  - 

@conference{
author = "Mrđinac, Jelena Ž. and Marković, Olivera S. and Pešić, Miloš P. and Verbić, Tatjana",
year = "2022",
abstract = "The ionization constant (usually expressed in logarithmic form, pKa) is important 
physicochemical parameter which is used to characterize the acid-base chemistry of a 
compound. Since most drugs contain one or more ionizable functional groups, 
knowledge of pKa values is necessary in drug research. The most common techniques 
used for pKa determination are potentiometry and spectrophotometry. Potentiometry is 
a method of choice when ionization processes are overlapping, as in such case it is not 
possible to obtain the absorption spectrum of each species present in solution. The aim 
of this work was the comparative analysis of pKa determination using potentiometry and 
spectrophotometry for model compounds with overlapping ionization processes: 3-
aminobenzoic acid, 1,3,5-benzenetricarboxylic acid and tyrosine. The potentiometric
titrations were performed with pSOL Model 3 instrument (pION) equipped with pS 
software package for titration data analysis.1 Avdeef–Bucher four–parameter equation 
was used for electrode standardization.2 To overcome the above-mentioned limitation of 
spectrophotometry, the alternative approach was applied in this study. The new 
aminocaproate phosphate buffer (containing phosphoric and ε-aminocaproic acids) was 
used for the solutions preparation of the model compounds in pH range 1 – 12. This 
buffer has numerous advantages like UV-transparency, resistance to pH changes upon 
standing for several days, useful buffer capacity and constant ionic strength in the wide 
range of pH values. Absorption spectra were recorded according to specific procedure 
which was carefully designed to avoid systematic errors. Collected absorption spectra 
will be used for the development of the algorithm for the spectral deconvolution (using 
MATLAB). Such software can be very useful tool in the drug research, especially for 
the analysis of the compounds which pKa values cannot be determined by potentiometry.",
publisher = "Belgrade : Serbian Chemical Society, Belgrade : Serbian Young Chemists’ Club",
journal = "8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts",
title = "Comparative  analysis of ionization constants determination using spectrophotometry and potentiometry: 3- aminobenzoic acid, 1,3,5-benzenetricarboxylic acid and tyrosine",
pages = "42-42",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5939"
}

Mrđinac, J. Ž., Marković, O. S., Pešić, M. P.,& Verbić, T.. (2022). Comparative  analysis of ionization constants determination using spectrophotometry and potentiometry: 3- aminobenzoic acid, 1,3,5-benzenetricarboxylic acid and tyrosine. in 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts
Belgrade : Serbian Chemical Society., 42-42.
https://hdl.handle.net/21.15107/rcub_cherry_5939

Mrđinac JŽ, Marković OS, Pešić MP, Verbić T. Comparative  analysis of ionization constants determination using spectrophotometry and potentiometry: 3- aminobenzoic acid, 1,3,5-benzenetricarboxylic acid and tyrosine. in 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts. 2022;:42-42.
https://hdl.handle.net/21.15107/rcub_cherry_5939 .

Mrđinac, Jelena Ž., Marković, Olivera S., Pešić, Miloš P., Verbić, Tatjana, "Comparative  analysis of ionization constants determination using spectrophotometry and potentiometry: 3- aminobenzoic acid, 1,3,5-benzenetricarboxylic acid and tyrosine" in 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. In: Book of Abstracts (2022):42-42,
https://hdl.handle.net/21.15107/rcub_cherry_5939 .

TY  - CONF
AU  - Marković, Olivera S.
AU  - Gajić, Brankica P.
AU  - Pešić, Miloš P.
AU  - Verbić, Tatjana
PY  - 2022
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5940
AB  - Cilj ovog rada bio je proučavanje ravnoteža u heterogenim sistemima tricikličnog 
antidepresiva amitriptilina (Am) koji sadrže hloride i/ili fosfate. Rastvorljivost Am u 
uslovima povećane jonske sile određena je pH–Ramp shake–flask metodom.1, 2 Veća 
rastvorljivost Am u kiseloj sredini od očekivane, posledica je agregacije – analiza 
eksperimentalnih podataka pomoću programa pDISOL–XTM ukazuje na verovatno 
građenje pentamera Am5H5
5+. Kritična micelarna koncentracija i stepen disocijacije 
agregata određeni su primenom konduktometrijskih titracija. U baznoj sredini primećena je 
delimična degradacija Am. Eksperimentalno dobijeni podaci o rastvorljivosti biološki 
aktivnih supstanci i postojećim ravnotežama u heterogenim sistemima važni su u svim 
fazama dizajna i razvoja lekova.
AB  - The aim of this work was to study the equilibria in tricyclic antidepressant amitriptyline 
(Am) heterogeneous systems containing chloride and/or phosphate ions. Solubility of Am 
in high ionic strength conditions was determined using pH–Ramp shake–flask method.1, 2
Higher solubility of Am than expected in an acidic media is a consequence of self aggregation – pentamer formation (Am5H5
5+) according to pDISOL–XTM analysis. Critical 
micelle concentration and the degree of the aggregate dissociation were determined by 
conductometric titrations. Partial degradation of Am in alkaline suspensions was observed. 
Experimental studies of solubility as well as the existing equilibria in heterogeneous 
systems of biologically active compounds are important at all stages of drug design and 
development.
PB  - Beograd : Srpsko hemijsko društvo
C3  - 58. Savetovanje Srpskog hemijskog društva, Kratki izvodi radova, Beograd 9. i 10. jun 2022. godine
T1  - Proučavanje ravnoteža u heterogenim sistemima tricikličnog  antidepresiva amitriptilina
SP  - 53
EP  - 53
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5940
ER  - 

@conference{
author = "Marković, Olivera S. and Gajić, Brankica P. and Pešić, Miloš P. and Verbić, Tatjana",
year = "2022",
abstract = "Cilj ovog rada bio je proučavanje ravnoteža u heterogenim sistemima tricikličnog 
antidepresiva amitriptilina (Am) koji sadrže hloride i/ili fosfate. Rastvorljivost Am u 
uslovima povećane jonske sile određena je pH–Ramp shake–flask metodom.1, 2 Veća 
rastvorljivost Am u kiseloj sredini od očekivane, posledica je agregacije – analiza 
eksperimentalnih podataka pomoću programa pDISOL–XTM ukazuje na verovatno 
građenje pentamera Am5H5
5+. Kritična micelarna koncentracija i stepen disocijacije 
agregata određeni su primenom konduktometrijskih titracija. U baznoj sredini primećena je 
delimična degradacija Am. Eksperimentalno dobijeni podaci o rastvorljivosti biološki 
aktivnih supstanci i postojećim ravnotežama u heterogenim sistemima važni su u svim 
fazama dizajna i razvoja lekova., The aim of this work was to study the equilibria in tricyclic antidepressant amitriptyline 
(Am) heterogeneous systems containing chloride and/or phosphate ions. Solubility of Am 
in high ionic strength conditions was determined using pH–Ramp shake–flask method.1, 2
Higher solubility of Am than expected in an acidic media is a consequence of self aggregation – pentamer formation (Am5H5
5+) according to pDISOL–XTM analysis. Critical 
micelle concentration and the degree of the aggregate dissociation were determined by 
conductometric titrations. Partial degradation of Am in alkaline suspensions was observed. 
Experimental studies of solubility as well as the existing equilibria in heterogeneous 
systems of biologically active compounds are important at all stages of drug design and 
development.",
publisher = "Beograd : Srpsko hemijsko društvo",
journal = "58. Savetovanje Srpskog hemijskog društva, Kratki izvodi radova, Beograd 9. i 10. jun 2022. godine",
title = "Proučavanje ravnoteža u heterogenim sistemima tricikličnog  antidepresiva amitriptilina",
pages = "53-53",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5940"
}

Marković, O. S., Gajić, B. P., Pešić, M. P.,& Verbić, T.. (2022). Proučavanje ravnoteža u heterogenim sistemima tricikličnog  antidepresiva amitriptilina. in 58. Savetovanje Srpskog hemijskog društva, Kratki izvodi radova, Beograd 9. i 10. jun 2022. godine
Beograd : Srpsko hemijsko društvo., 53-53.
https://hdl.handle.net/21.15107/rcub_cherry_5940

Marković OS, Gajić BP, Pešić MP, Verbić T. Proučavanje ravnoteža u heterogenim sistemima tricikličnog  antidepresiva amitriptilina. in 58. Savetovanje Srpskog hemijskog društva, Kratki izvodi radova, Beograd 9. i 10. jun 2022. godine. 2022;:53-53.
https://hdl.handle.net/21.15107/rcub_cherry_5940 .

Marković, Olivera S., Gajić, Brankica P., Pešić, Miloš P., Verbić, Tatjana, "Proučavanje ravnoteža u heterogenim sistemima tricikličnog  antidepresiva amitriptilina" in 58. Savetovanje Srpskog hemijskog društva, Kratki izvodi radova, Beograd 9. i 10. jun 2022. godine (2022):53-53,
https://hdl.handle.net/21.15107/rcub_cherry_5940 .

TY  - CONF
AU  - Мрђан, Горана
AU  - Ваштаг, Ђенђи
AU  - Апостолов, Сузана
AU  - Рашета, Милена
AU  - Вербић, Татјана
AU  - Марковић, Оливера С.
AU  - Матијевић, Борко
PY  - 2022
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5968
AB  - Карбохидразони и њихови тио-аналози представљају
једињења добијена кондензацијом карбохидразида, односно тиокарбохи-
дразида са карбонилним једињењима. Захваљујући њиховој структури,
релативно једноставној синтези и великој реактивности, поменути дери-
вати имају широк спектар примене у свим сферама. У оквиру овог рада,
за четири новосинтетисана моно(тио)карбохидразона, одређене су кисе-
линске константе применом потенциметријске методе. Такође, методом
линеарне корелације енергија солватације и применом Catalan-овог моде-
ла испитан је утицај специфичних и неспецифичних међумолекулских
интеракција на померања у UV-Vis апсорпционим спектрима. У циљу
испитивавања потенцијалне биолошке активности 2 - пиридин-(тио) кар-
бохидразона, применом DPPH теста, одређен је њихов антиоксидативни
потенцијал и закључено је да су деривати тиокарбохидразона значајно
активнији у односу на карбохидразоне.
PB  - Бања Лука : Академија наука и умјетности Републике Српске
C3  - Међународни научни скуп Савремени материјали, Бања Лука, 2022.
T1  - Ispitivanje fizičko-hemijskih svojstava i potencijalne biološke aktivnosti derivata 2-piridin-(tio)karbohidrazona
VL  - 46
SP  - 275
EP  - 285
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5968
ER  - 

@conference{
author = "Мрђан, Горана and Ваштаг, Ђенђи and Апостолов, Сузана and Рашета, Милена and Вербић, Татјана and Марковић, Оливера С. and Матијевић, Борко",
year = "2022",
abstract = "Карбохидразони и њихови тио-аналози представљају
једињења добијена кондензацијом карбохидразида, односно тиокарбохи-
дразида са карбонилним једињењима. Захваљујући њиховој структури,
релативно једноставној синтези и великој реактивности, поменути дери-
вати имају широк спектар примене у свим сферама. У оквиру овог рада,
за четири новосинтетисана моно(тио)карбохидразона, одређене су кисе-
линске константе применом потенциметријске методе. Такође, методом
линеарне корелације енергија солватације и применом Catalan-овог моде-
ла испитан је утицај специфичних и неспецифичних међумолекулских
интеракција на померања у UV-Vis апсорпционим спектрима. У циљу
испитивавања потенцијалне биолошке активности 2 - пиридин-(тио) кар-
бохидразона, применом DPPH теста, одређен је њихов антиоксидативни
потенцијал и закључено је да су деривати тиокарбохидразона значајно
активнији у односу на карбохидразоне.",
publisher = "Бања Лука : Академија наука и умјетности Републике Српске",
journal = "Међународни научни скуп Савремени материјали, Бања Лука, 2022.",
title = "Ispitivanje fizičko-hemijskih svojstava i potencijalne biološke aktivnosti derivata 2-piridin-(tio)karbohidrazona",
volume = "46",
pages = "275-285",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5968"
}

Мрђан, Г., Ваштаг, Ђ., Апостолов, С., Рашета, М., Вербић, Т., Марковић, О. С.,& Матијевић, Б.. (2022). Ispitivanje fizičko-hemijskih svojstava i potencijalne biološke aktivnosti derivata 2-piridin-(tio)karbohidrazona. in Међународни научни скуп Савремени материјали, Бања Лука, 2022.
Бања Лука : Академија наука и умјетности Републике Српске., 46, 275-285.
https://hdl.handle.net/21.15107/rcub_cherry_5968

Мрђан Г, Ваштаг Ђ, Апостолов С, Рашета М, Вербић Т, Марковић ОС, Матијевић Б. Ispitivanje fizičko-hemijskih svojstava i potencijalne biološke aktivnosti derivata 2-piridin-(tio)karbohidrazona. in Међународни научни скуп Савремени материјали, Бања Лука, 2022.. 2022;46:275-285.
https://hdl.handle.net/21.15107/rcub_cherry_5968 .

Мрђан, Горана, Ваштаг, Ђенђи, Апостолов, Сузана, Рашета, Милена, Вербић, Татјана, Марковић, Оливера С., Матијевић, Борко, "Ispitivanje fizičko-hemijskih svojstava i potencijalne biološke aktivnosti derivata 2-piridin-(tio)karbohidrazona" in Међународни научни скуп Савремени материјали, Бања Лука, 2022., 46 (2022):275-285,
https://hdl.handle.net/21.15107/rcub_cherry_5968 .

TY  - JOUR
AU  - Krunić, Matija
AU  - Ristić, Biljana
AU  - Bošnjak, Mihajlo
AU  - Paunović, Verica
AU  - Tovilović-Kovačević, Gordana
AU  - Zagović, Nevena
AU  - Mirčić, Aleksandar
AU  - Marković, Zoran
AU  - Todorović Marković, Biljana
AU  - Jovanović, Svetlana
AU  - Kleut, Duška
AU  - Mojović, Miloš
AU  - Nakarada, Đura
AU  - Marković, Olivera S.
AU  - Vuković, Irena
AU  - Harhaji-Trajković, Ljubica
AU  - Trajković, Vladimir
PY  - 2021
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5467
AB  - We investigated the ability of graphene quantum dot (GQD) nanoparticles to protect SH-SY5Y human neuro blastoma cells from oxidative/nitrosative stress induced by iron-nitrosyl complex sodium nitroprusside (SNP). 
GQD reduced SNP cytotoxicity by preventing mitochondrial depolarization, caspase-2 activation, and subsequent 
apoptotic death. Although GQD diminished the levels of nitric oxide (NO) in SNP-exposed cells, NO scavengers 
displayed only a slight protective effect, suggesting that NO quenching was not the main protective mechanism of 
GQD. GQD also reduced SNP-triggered increase in the intracellular levels of hydroxyl radical (
•
OH), superoxide 
anion (O2
•− ), and lipid peroxidation. Nonselective antioxidants, •
OH scavenging, and iron chelators, but not 
superoxide dismutase, mimicked GQD cytoprotective activity, indicating that GQD protect cells by neutralizing •
OH generated in the presence of SNP-released iron. Cellular internalization of GQD was required for optimal 
protection, since a removal of extracellular GQD by extensive washing only partly diminished their protective 
effect. Moreover, GQD cooperated with SNP to induce autophagy, as confirmed by the inhibition of autophagy limiting Akt/PRAS40/mTOR signaling and increase in autophagy gene transcription, protein levels of proauto phagic beclin-1 and LC3-II, formation of autophagic vesicles, and degradation of autophagic target p62. The 
antioxidant activity of GQD was not involved in autophagy induction, as antioxidants N-acetylcysteine and 
dimethyl sulfoxide failed to stimulate autophagy in SNP-exposed cells. Pharmacological inhibitors of early 
(wortmannin, 3-methyladenine) or late stages of autophagy (NH4Cl) efficiently reduced the protective effect of 
GQD. Therefore, the ability of GQD to prevent the in vitro neurotoxicity of SNP depends on both •
OH/NO 
scavenging and induction of cytoprotective autophagy.
PB  - Elsevier
T2  - Free Radical Biology and Medicine
T1  - Graphene quantum dot antioxidant and proautophagic actions protect  SH-SY5Y neuroblastoma cells from oxidative stress-mediated  apoptotic death
VL  - 177
SP  - 167
EP  - 180
DO  - 10.1016/j.freeradbiomed.2021.10.025
ER  - 

@article{
author = "Krunić, Matija and Ristić, Biljana and Bošnjak, Mihajlo and Paunović, Verica and Tovilović-Kovačević, Gordana and Zagović, Nevena and Mirčić, Aleksandar and Marković, Zoran and Todorović Marković, Biljana and Jovanović, Svetlana and Kleut, Duška and Mojović, Miloš and Nakarada, Đura and Marković, Olivera S. and Vuković, Irena and Harhaji-Trajković, Ljubica and Trajković, Vladimir",
year = "2021",
abstract = "We investigated the ability of graphene quantum dot (GQD) nanoparticles to protect SH-SY5Y human neuro blastoma cells from oxidative/nitrosative stress induced by iron-nitrosyl complex sodium nitroprusside (SNP). 
GQD reduced SNP cytotoxicity by preventing mitochondrial depolarization, caspase-2 activation, and subsequent 
apoptotic death. Although GQD diminished the levels of nitric oxide (NO) in SNP-exposed cells, NO scavengers 
displayed only a slight protective effect, suggesting that NO quenching was not the main protective mechanism of 
GQD. GQD also reduced SNP-triggered increase in the intracellular levels of hydroxyl radical (
•
OH), superoxide 
anion (O2
•− ), and lipid peroxidation. Nonselective antioxidants, •
OH scavenging, and iron chelators, but not 
superoxide dismutase, mimicked GQD cytoprotective activity, indicating that GQD protect cells by neutralizing •
OH generated in the presence of SNP-released iron. Cellular internalization of GQD was required for optimal 
protection, since a removal of extracellular GQD by extensive washing only partly diminished their protective 
effect. Moreover, GQD cooperated with SNP to induce autophagy, as confirmed by the inhibition of autophagy limiting Akt/PRAS40/mTOR signaling and increase in autophagy gene transcription, protein levels of proauto phagic beclin-1 and LC3-II, formation of autophagic vesicles, and degradation of autophagic target p62. The 
antioxidant activity of GQD was not involved in autophagy induction, as antioxidants N-acetylcysteine and 
dimethyl sulfoxide failed to stimulate autophagy in SNP-exposed cells. Pharmacological inhibitors of early 
(wortmannin, 3-methyladenine) or late stages of autophagy (NH4Cl) efficiently reduced the protective effect of 
GQD. Therefore, the ability of GQD to prevent the in vitro neurotoxicity of SNP depends on both •
OH/NO 
scavenging and induction of cytoprotective autophagy.",
publisher = "Elsevier",
journal = "Free Radical Biology and Medicine",
title = "Graphene quantum dot antioxidant and proautophagic actions protect  SH-SY5Y neuroblastoma cells from oxidative stress-mediated  apoptotic death",
volume = "177",
pages = "167-180",
doi = "10.1016/j.freeradbiomed.2021.10.025"
}

Krunić, M., Ristić, B., Bošnjak, M., Paunović, V., Tovilović-Kovačević, G., Zagović, N., Mirčić, A., Marković, Z., Todorović Marković, B., Jovanović, S., Kleut, D., Mojović, M., Nakarada, Đ., Marković, O. S., Vuković, I., Harhaji-Trajković, L.,& Trajković, V.. (2021). Graphene quantum dot antioxidant and proautophagic actions protect  SH-SY5Y neuroblastoma cells from oxidative stress-mediated  apoptotic death. in Free Radical Biology and Medicine
Elsevier., 177, 167-180.
https://doi.org/10.1016/j.freeradbiomed.2021.10.025

Krunić M, Ristić B, Bošnjak M, Paunović V, Tovilović-Kovačević G, Zagović N, Mirčić A, Marković Z, Todorović Marković B, Jovanović S, Kleut D, Mojović M, Nakarada Đ, Marković OS, Vuković I, Harhaji-Trajković L, Trajković V. Graphene quantum dot antioxidant and proautophagic actions protect  SH-SY5Y neuroblastoma cells from oxidative stress-mediated  apoptotic death. in Free Radical Biology and Medicine. 2021;177:167-180.
doi:10.1016/j.freeradbiomed.2021.10.025 .

Krunić, Matija, Ristić, Biljana, Bošnjak, Mihajlo, Paunović, Verica, Tovilović-Kovačević, Gordana, Zagović, Nevena, Mirčić, Aleksandar, Marković, Zoran, Todorović Marković, Biljana, Jovanović, Svetlana, Kleut, Duška, Mojović, Miloš, Nakarada, Đura, Marković, Olivera S., Vuković, Irena, Harhaji-Trajković, Ljubica, Trajković, Vladimir, "Graphene quantum dot antioxidant and proautophagic actions protect  SH-SY5Y neuroblastoma cells from oxidative stress-mediated  apoptotic death" in Free Radical Biology and Medicine, 177 (2021):167-180,
https://doi.org/10.1016/j.freeradbiomed.2021.10.025 . .

TY  - JOUR
AU  - Mrđan, Gorana S.
AU  - Vastag, Gyöngyi Gy.
AU  - Škorić, Dušan Đ.
AU  - Radanović, Mirjana M.
AU  - Verbić, Tatjana
AU  - Milčić, Miloš K.
AU  - Stojiljković, Ivana N.
AU  - Marković, Olivera S.
AU  - Matijević, Borko M.
PY  - 2021
UR  - https://cherry.chem.bg.ac.rs/handle/123456789/4453
AB  - Derivatives of thiocarbohydrazone studied so far have shown great biological activity such as antioxidant, antimicrobial, and anticancer. Most of these compounds are bis-substituted derivatives, while monothiocarbohydrazones are much less investigated. Еighteen monothiocarbohydrazones were synthesized and subjected to physicochemical characterization in order to facilitate the examination of their potential biological activity and application in future studies. The structure of synthesized derivatives was confirmed with NMR and FT–IR spectroscopy, and with elemental analysis. For one of the compounds, single-crystal X-ray diffraction analysis was performed. Specific and non-specific molecular interactions were interpreted by LSER principles, using Catalan’s model. For additional information about the dominance and influence of the interactions presented, correlations with Hansen’s solubility parameters were calculated. Influence of the type and position of the substituent on absorption maxima was determined with LFER (linear free-energy relationship) principles, using Hammett’s equation. Acidity constants of the synthesized compounds were theoretically calculated and experimentally determined. Moreover, the excitation of a molecule by a photon of UV–Vis light was interpreted by time-dependent density functional theory (TD–DFT) calculations of UV absorption bands, and intramolecular charge transfer (ICT) was quantified by calculations of the charge transfer distances (DCT). © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.
PB  - Springer Nature
T2  - Structural Chemistry
T2  - Structural Chemistry
T2  - Structural Chemistry
T1  - Synthesis, physicochemical characterization, and TD–DFT calculations of monothiocarbohydrazone derivatives
VL  - 32
IS  - 3
SP  - 1231
EP  - 1245
DO  - 10.1007/s11224-020-01700-y
ER  - 

@article{
author = "Mrđan, Gorana S. and Vastag, Gyöngyi Gy. and Škorić, Dušan Đ. and Radanović, Mirjana M. and Verbić, Tatjana and Milčić, Miloš K. and Stojiljković, Ivana N. and Marković, Olivera S. and Matijević, Borko M.",
year = "2021",
abstract = "Derivatives of thiocarbohydrazone studied so far have shown great biological activity such as antioxidant, antimicrobial, and anticancer. Most of these compounds are bis-substituted derivatives, while monothiocarbohydrazones are much less investigated. Еighteen monothiocarbohydrazones were synthesized and subjected to physicochemical characterization in order to facilitate the examination of their potential biological activity and application in future studies. The structure of synthesized derivatives was confirmed with NMR and FT–IR spectroscopy, and with elemental analysis. For one of the compounds, single-crystal X-ray diffraction analysis was performed. Specific and non-specific molecular interactions were interpreted by LSER principles, using Catalan’s model. For additional information about the dominance and influence of the interactions presented, correlations with Hansen’s solubility parameters were calculated. Influence of the type and position of the substituent on absorption maxima was determined with LFER (linear free-energy relationship) principles, using Hammett’s equation. Acidity constants of the synthesized compounds were theoretically calculated and experimentally determined. Moreover, the excitation of a molecule by a photon of UV–Vis light was interpreted by time-dependent density functional theory (TD–DFT) calculations of UV absorption bands, and intramolecular charge transfer (ICT) was quantified by calculations of the charge transfer distances (DCT). © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.",
publisher = "Springer Nature",
journal = "Structural Chemistry, Structural Chemistry, Structural Chemistry",
title = "Synthesis, physicochemical characterization, and TD–DFT calculations of monothiocarbohydrazone derivatives",
volume = "32",
number = "3",
pages = "1231-1245",
doi = "10.1007/s11224-020-01700-y"
}

Mrđan, G. S., Vastag, G. Gy., Škorić, D. Đ., Radanović, M. M., Verbić, T., Milčić, M. K., Stojiljković, I. N., Marković, O. S.,& Matijević, B. M.. (2021). Synthesis, physicochemical characterization, and TD–DFT calculations of monothiocarbohydrazone derivatives. in Structural Chemistry
Springer Nature., 32(3), 1231-1245.
https://doi.org/10.1007/s11224-020-01700-y

Mrđan GS, Vastag GG, Škorić DĐ, Radanović MM, Verbić T, Milčić MK, Stojiljković IN, Marković OS, Matijević BM. Synthesis, physicochemical characterization, and TD–DFT calculations of monothiocarbohydrazone derivatives. in Structural Chemistry. 2021;32(3):1231-1245.
doi:10.1007/s11224-020-01700-y .

Mrđan, Gorana S., Vastag, Gyöngyi Gy., Škorić, Dušan Đ., Radanović, Mirjana M., Verbić, Tatjana, Milčić, Miloš K., Stojiljković, Ivana N., Marković, Olivera S., Matijević, Borko M., "Synthesis, physicochemical characterization, and TD–DFT calculations of monothiocarbohydrazone derivatives" in Structural Chemistry, 32, no. 3 (2021):1231-1245,
https://doi.org/10.1007/s11224-020-01700-y . .

TY  - DATA
AU  - Mrđan, Gorana S.
AU  - Vastag, Gyöngyi Gy.
AU  - Škorić, Dušan Đ.
AU  - Radanović, Mirjana M.
AU  - Verbić, Tatjana
AU  - Milčić, Miloš K.
AU  - Stojiljković, Ivana N.
AU  - Marković, Olivera S.
AU  - Matijević, Borko M.
PY  - 2021
UR  - https://cherry.chem.bg.ac.rs/handle/123456789/4454
PB  - Springer Nature
T2  - Structural Chemistry
T1  - Supplementary data for the article: Mrđan, G. S.; Vastag, G. G.; Škorić, D. Đ.; Radanović, M. M.; Verbić, T. Ž.; Milčić, M. K.; Stojiljković, I. N.; Marković, O. S.; Matijević, B. M. Synthesis, Physicochemical Characterization, and TD–DFT Calculations of Monothiocarbohydrazone Derivatives. Structural Chemistry 2021, 32 (3), 1231–1245. https://doi.org/10.1007/s11224-020-01700-y.
UR  - https://hdl.handle.net/21.15107/rcub_cherry_4454
ER  - 

@misc{
author = "Mrđan, Gorana S. and Vastag, Gyöngyi Gy. and Škorić, Dušan Đ. and Radanović, Mirjana M. and Verbić, Tatjana and Milčić, Miloš K. and Stojiljković, Ivana N. and Marković, Olivera S. and Matijević, Borko M.",
year = "2021",
publisher = "Springer Nature",
journal = "Structural Chemistry",
title = "Supplementary data for the article: Mrđan, G. S.; Vastag, G. G.; Škorić, D. Đ.; Radanović, M. M.; Verbić, T. Ž.; Milčić, M. K.; Stojiljković, I. N.; Marković, O. S.; Matijević, B. M. Synthesis, Physicochemical Characterization, and TD–DFT Calculations of Monothiocarbohydrazone Derivatives. Structural Chemistry 2021, 32 (3), 1231–1245. https://doi.org/10.1007/s11224-020-01700-y.",
url = "https://hdl.handle.net/21.15107/rcub_cherry_4454"
}

Mrđan, G. S., Vastag, G. Gy., Škorić, D. Đ., Radanović, M. M., Verbić, T., Milčić, M. K., Stojiljković, I. N., Marković, O. S.,& Matijević, B. M.. (2021). Supplementary data for the article: Mrđan, G. S.; Vastag, G. G.; Škorić, D. Đ.; Radanović, M. M.; Verbić, T. Ž.; Milčić, M. K.; Stojiljković, I. N.; Marković, O. S.; Matijević, B. M. Synthesis, Physicochemical Characterization, and TD–DFT Calculations of Monothiocarbohydrazone Derivatives. Structural Chemistry 2021, 32 (3), 1231–1245. https://doi.org/10.1007/s11224-020-01700-y.. in Structural Chemistry
Springer Nature..
https://hdl.handle.net/21.15107/rcub_cherry_4454

Mrđan GS, Vastag GG, Škorić DĐ, Radanović MM, Verbić T, Milčić MK, Stojiljković IN, Marković OS, Matijević BM. Supplementary data for the article: Mrđan, G. S.; Vastag, G. G.; Škorić, D. Đ.; Radanović, M. M.; Verbić, T. Ž.; Milčić, M. K.; Stojiljković, I. N.; Marković, O. S.; Matijević, B. M. Synthesis, Physicochemical Characterization, and TD–DFT Calculations of Monothiocarbohydrazone Derivatives. Structural Chemistry 2021, 32 (3), 1231–1245. https://doi.org/10.1007/s11224-020-01700-y.. in Structural Chemistry. 2021;.
https://hdl.handle.net/21.15107/rcub_cherry_4454 .

Mrđan, Gorana S., Vastag, Gyöngyi Gy., Škorić, Dušan Đ., Radanović, Mirjana M., Verbić, Tatjana, Milčić, Miloš K., Stojiljković, Ivana N., Marković, Olivera S., Matijević, Borko M., "Supplementary data for the article: Mrđan, G. S.; Vastag, G. G.; Škorić, D. Đ.; Radanović, M. M.; Verbić, T. Ž.; Milčić, M. K.; Stojiljković, I. N.; Marković, O. S.; Matijević, B. M. Synthesis, Physicochemical Characterization, and TD–DFT Calculations of Monothiocarbohydrazone Derivatives. Structural Chemistry 2021, 32 (3), 1231–1245. https://doi.org/10.1007/s11224-020-01700-y." in Structural Chemistry (2021),
https://hdl.handle.net/21.15107/rcub_cherry_4454 .

TY  - CONF
AU  - Marković, Olivera S.
AU  - Marjanović, Nemanja Ž.
AU  - Patel, Nirali
AU  - Serajuddin, Abu T. M.
AU  - Avdeef, Alex
AU  - Verbić, Tatjana
PY  - 2021
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5962
AB  - Solubility is important physicochemical parameter and determines drug stability, bioavailability and therapeutic action. The aim of this study was to examine solubility of nortriptyline hydrochloride in a wide pH range, using pH-Ramp Shake-Flask method, already applied to desipramine hydrochloride [1] and based of recently published recommendations [2]. Solubility was measured in phosphate buffer, in chloride-free media and phoshate-free media, using both nortriptyline base and nortriptyline hydrochloride as starting material. Elemental analysis, termogravimetric analysis, differential scaning calorimetric analysis and powder X-ray diffraction analysis were used for solid precipitate analysis.
AB  - Rastvorljivost je značajno fizičko-hemijsko svojstvo biološki aktivnih i potencijalno biološki aktivnih supstancija, koje određuje stabilnost, biodostupnost i terapeutsko dejstvo leka. Cilj ovog rada je ispitivanje rastvorljivosti nortriptilin-hidrohlorida, pomoću pH-Ramp Shake-Flask metode, prethodno primenjene na desipramin-hidrohlorid [1]. Eksperimenti su izvedeni prema novim preporukama iz literature [2]. Rastvorljivost je određena u fosfatnom puferu, u sistemu bez hlorida i sistemu bez fosfata, koristeći nortriptilin bazu i nortriptilin-hidrohlorid. Urađena je i katakterizacija čvrste faze pomoću elementalne analize, termogravimetrije, diferencijalne skenirajuće kalorimetrije i difrakcije X-zraka.
PB  - Belgrade : Serbian Chemical Society
C3  - 57th Meeting of the Serbian chemical Society - Proceedings / 57. Savetovanje Srpskog hemijskog društva - Knjiga radova, Kragujevac, Serbia, June 18-19, 2021
T1  - pH-Dependent solubility profile of nortriptyline hydrochloride
SP  - 32
EP  - 32
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5962
ER  - 

@conference{
author = "Marković, Olivera S. and Marjanović, Nemanja Ž. and Patel, Nirali and Serajuddin, Abu T. M. and Avdeef, Alex and Verbić, Tatjana",
year = "2021",
abstract = "Solubility is important physicochemical parameter and determines drug stability, bioavailability and therapeutic action. The aim of this study was to examine solubility of nortriptyline hydrochloride in a wide pH range, using pH-Ramp Shake-Flask method, already applied to desipramine hydrochloride [1] and based of recently published recommendations [2]. Solubility was measured in phosphate buffer, in chloride-free media and phoshate-free media, using both nortriptyline base and nortriptyline hydrochloride as starting material. Elemental analysis, termogravimetric analysis, differential scaning calorimetric analysis and powder X-ray diffraction analysis were used for solid precipitate analysis., Rastvorljivost je značajno fizičko-hemijsko svojstvo biološki aktivnih i potencijalno biološki aktivnih supstancija, koje određuje stabilnost, biodostupnost i terapeutsko dejstvo leka. Cilj ovog rada je ispitivanje rastvorljivosti nortriptilin-hidrohlorida, pomoću pH-Ramp Shake-Flask metode, prethodno primenjene na desipramin-hidrohlorid [1]. Eksperimenti su izvedeni prema novim preporukama iz literature [2]. Rastvorljivost je određena u fosfatnom puferu, u sistemu bez hlorida i sistemu bez fosfata, koristeći nortriptilin bazu i nortriptilin-hidrohlorid. Urađena je i katakterizacija čvrste faze pomoću elementalne analize, termogravimetrije, diferencijalne skenirajuće kalorimetrije i difrakcije X-zraka.",
publisher = "Belgrade : Serbian Chemical Society",
journal = "57th Meeting of the Serbian chemical Society - Proceedings / 57. Savetovanje Srpskog hemijskog društva - Knjiga radova, Kragujevac, Serbia, June 18-19, 2021",
title = "pH-Dependent solubility profile of nortriptyline hydrochloride",
pages = "32-32",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5962"
}

Marković, O. S., Marjanović, N. Ž., Patel, N., Serajuddin, A. T. M., Avdeef, A.,& Verbić, T.. (2021). pH-Dependent solubility profile of nortriptyline hydrochloride. in 57th Meeting of the Serbian chemical Society - Proceedings / 57. Savetovanje Srpskog hemijskog društva - Knjiga radova, Kragujevac, Serbia, June 18-19, 2021
Belgrade : Serbian Chemical Society., 32-32.
https://hdl.handle.net/21.15107/rcub_cherry_5962

Marković OS, Marjanović NŽ, Patel N, Serajuddin ATM, Avdeef A, Verbić T. pH-Dependent solubility profile of nortriptyline hydrochloride. in 57th Meeting of the Serbian chemical Society - Proceedings / 57. Savetovanje Srpskog hemijskog društva - Knjiga radova, Kragujevac, Serbia, June 18-19, 2021. 2021;:32-32.
https://hdl.handle.net/21.15107/rcub_cherry_5962 .

Marković, Olivera S., Marjanović, Nemanja Ž., Patel, Nirali, Serajuddin, Abu T. M., Avdeef, Alex, Verbić, Tatjana, "pH-Dependent solubility profile of nortriptyline hydrochloride" in 57th Meeting of the Serbian chemical Society - Proceedings / 57. Savetovanje Srpskog hemijskog društva - Knjiga radova, Kragujevac, Serbia, June 18-19, 2021 (2021):32-32,
https://hdl.handle.net/21.15107/rcub_cherry_5962 .

TY  - CONF
AU  - Mrđan, Gorana
AU  - Vaštag, Đenđi
AU  - Apostolov, Suzana
AU  - Rašeta, Milena
AU  - Verbić, Tatjana
AU  - Marković, Olivera S.
AU  - Matijević, Borko
PY  - 2021
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5963
AB  - Carbohydrazones and their thio analogs represent compounds obtained
by condensation of carbohydrazide and thiocarbohydrazide with carbonyl
compounds. Due to their structure, relatively simple synthesis, and high reactivity,
mentioned derivatives have a wide range of applications in all fields. In this study,
ionization constants of four newly synthesized mono(thio)carbohydrazones were
determined by applying the potentiometric method. Also, the influence of specific
and nonspecific intermolecular interactions on maxima shifting in UV-Vis absorption
spectra was investigated and quantified using the linear solvation energy relationships
method and Catalan’s model. Finally, by applying the DPPH assay, the
antioxidant potential of the newly synthesized compounds was determined, and thiocarbohydrazone
derivatives proved to be significantly more active when compared
to carbohydrazones.
C3  - XIV International Scientific Conference Contemporary Materials 2021 Programme and the Book of Abstracts, Banja Luka, September 9th to 10th, 2021
T1  - Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives
SP  - 40
EP  - 40
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5963
ER  - 

@conference{
author = "Mrđan, Gorana and Vaštag, Đenđi and Apostolov, Suzana and Rašeta, Milena and Verbić, Tatjana and Marković, Olivera S. and Matijević, Borko",
year = "2021",
abstract = "Carbohydrazones and their thio analogs represent compounds obtained
by condensation of carbohydrazide and thiocarbohydrazide with carbonyl
compounds. Due to their structure, relatively simple synthesis, and high reactivity,
mentioned derivatives have a wide range of applications in all fields. In this study,
ionization constants of four newly synthesized mono(thio)carbohydrazones were
determined by applying the potentiometric method. Also, the influence of specific
and nonspecific intermolecular interactions on maxima shifting in UV-Vis absorption
spectra was investigated and quantified using the linear solvation energy relationships
method and Catalan’s model. Finally, by applying the DPPH assay, the
antioxidant potential of the newly synthesized compounds was determined, and thiocarbohydrazone
derivatives proved to be significantly more active when compared
to carbohydrazones.",
journal = "XIV International Scientific Conference Contemporary Materials 2021 Programme and the Book of Abstracts, Banja Luka, September 9th to 10th, 2021",
title = "Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives",
pages = "40-40",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5963"
}

Mrđan, G., Vaštag, Đ., Apostolov, S., Rašeta, M., Verbić, T., Marković, O. S.,& Matijević, B.. (2021). Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives. in XIV International Scientific Conference Contemporary Materials 2021 Programme and the Book of Abstracts, Banja Luka, September 9th to 10th, 2021, 40-40.
https://hdl.handle.net/21.15107/rcub_cherry_5963

Mrđan G, Vaštag Đ, Apostolov S, Rašeta M, Verbić T, Marković OS, Matijević B. Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives. in XIV International Scientific Conference Contemporary Materials 2021 Programme and the Book of Abstracts, Banja Luka, September 9th to 10th, 2021. 2021;:40-40.
https://hdl.handle.net/21.15107/rcub_cherry_5963 .

Mrđan, Gorana, Vaštag, Đenđi, Apostolov, Suzana, Rašeta, Milena, Verbić, Tatjana, Marković, Olivera S., Matijević, Borko, "Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives" in XIV International Scientific Conference Contemporary Materials 2021 Programme and the Book of Abstracts, Banja Luka, September 9th to 10th, 2021 (2021):40-40,
https://hdl.handle.net/21.15107/rcub_cherry_5963 .

TY  - CONF
AU  - Dorontić, Slađana
AU  - Marković, Olivera S.
AU  - Kleut, Duška
AU  - Jovanović, Svetlana
PY  - 2021
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5964
AB  - In the era of pollution and hazardous materials, new methods for the detection of pollutants
in the environment are urgently needed. Due to their specific features such as
photoluminescence (PL) in the visible part of the spectrum, dispersibility in water, and
organic solvents, nontoxicity, and biocompatibility, graphene quantum dots (GQDs) attract
attention in optical sensing of various ions and molecules. In this study, pristine graphene
quantum dots (p-GQDs) were produced in a simple single-step electrochemical top-down
approach using graphite electrodes as a starting material, and dispersion of sodiumhydroxide
in 96% ethanol as a medium for electrochemical reaction. These p-GQDs were
gamma-irradiated in a dose of 25 kGy in presence of ethylenediamine in Ar medium to
introduce amino groups in their crystal lattice. Results obtained from AFM microscopy
indicate the height-uniformity of irradiated GQDs. The presence of amino groups in GQDs
was confirmed by FTIR, XPS, and UV-Vis spectroscopies. According to results obtained
from PL spectroscopy, a significant narrowing of emission band in irradiated GQDs was
observed. In further research, these GQDs were investigated as a potential PL sensor for iron
which is one of the most abundant heavy metal in the environment. In the preliminary
investigation, a water dispersion of irradiated GQDs was mixed with Fe(III) solution in
concentrations of 50 and 100 μM. Using a PL spectroscopy the PL intensity of irradiated
GQDs in presence of Fe (III) was measured. From the obtained results, it can be seen that
Fe(III) ions lead to quenching of GQDs PL intensity. Then, PL intensities were measured in
presence of Fe(III) ions in concentration range 0-100 μM. With an increase of Fe(III)
concentration, the PL intensity of GQDs decreased. It can be concluded that gammairradiated
amino-doped GQDs have significant potential in the so-called ,,turn of“ detection
of Fe(III) ions in the aqueous medium.
PB  - Belgrade : Institute of Technical Sciences of SASA
C3  - Nineteenth Young Researchers’ Conference Materials Science and Engineering, December 1-3, 2021, Belgrade, Serbia
T1  - Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions
SP  - 35
EP  - 35
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5964
ER  - 

@conference{
author = "Dorontić, Slađana and Marković, Olivera S. and Kleut, Duška and Jovanović, Svetlana",
year = "2021",
abstract = "In the era of pollution and hazardous materials, new methods for the detection of pollutants
in the environment are urgently needed. Due to their specific features such as
photoluminescence (PL) in the visible part of the spectrum, dispersibility in water, and
organic solvents, nontoxicity, and biocompatibility, graphene quantum dots (GQDs) attract
attention in optical sensing of various ions and molecules. In this study, pristine graphene
quantum dots (p-GQDs) were produced in a simple single-step electrochemical top-down
approach using graphite electrodes as a starting material, and dispersion of sodiumhydroxide
in 96% ethanol as a medium for electrochemical reaction. These p-GQDs were
gamma-irradiated in a dose of 25 kGy in presence of ethylenediamine in Ar medium to
introduce amino groups in their crystal lattice. Results obtained from AFM microscopy
indicate the height-uniformity of irradiated GQDs. The presence of amino groups in GQDs
was confirmed by FTIR, XPS, and UV-Vis spectroscopies. According to results obtained
from PL spectroscopy, a significant narrowing of emission band in irradiated GQDs was
observed. In further research, these GQDs were investigated as a potential PL sensor for iron
which is one of the most abundant heavy metal in the environment. In the preliminary
investigation, a water dispersion of irradiated GQDs was mixed with Fe(III) solution in
concentrations of 50 and 100 μM. Using a PL spectroscopy the PL intensity of irradiated
GQDs in presence of Fe (III) was measured. From the obtained results, it can be seen that
Fe(III) ions lead to quenching of GQDs PL intensity. Then, PL intensities were measured in
presence of Fe(III) ions in concentration range 0-100 μM. With an increase of Fe(III)
concentration, the PL intensity of GQDs decreased. It can be concluded that gammairradiated
amino-doped GQDs have significant potential in the so-called ,,turn of“ detection
of Fe(III) ions in the aqueous medium.",
publisher = "Belgrade : Institute of Technical Sciences of SASA",
journal = "Nineteenth Young Researchers’ Conference Materials Science and Engineering, December 1-3, 2021, Belgrade, Serbia",
title = "Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions",
pages = "35-35",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5964"
}

Dorontić, S., Marković, O. S., Kleut, D.,& Jovanović, S.. (2021). Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions. in Nineteenth Young Researchers’ Conference Materials Science and Engineering, December 1-3, 2021, Belgrade, Serbia
Belgrade : Institute of Technical Sciences of SASA., 35-35.
https://hdl.handle.net/21.15107/rcub_cherry_5964

Dorontić S, Marković OS, Kleut D, Jovanović S. Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions. in Nineteenth Young Researchers’ Conference Materials Science and Engineering, December 1-3, 2021, Belgrade, Serbia. 2021;:35-35.
https://hdl.handle.net/21.15107/rcub_cherry_5964 .

Dorontić, Slađana, Marković, Olivera S., Kleut, Duška, Jovanović, Svetlana, "Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions" in Nineteenth Young Researchers’ Conference Materials Science and Engineering, December 1-3, 2021, Belgrade, Serbia (2021):35-35,
https://hdl.handle.net/21.15107/rcub_cherry_5964 .

TY  - CONF
AU  - Dorontić, Slađana
AU  - Marković, Olivera S.
AU  - Kleut, Duška
AU  - Jovanović, Svetlana
PY  - 2021
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5966
AB  - We produced Graphene Quantum Dots (GQDs) by electrochemical oxidation of graphite rods and exposed them to gamma irradiation at a dose of 200 kGy, in the presence of ethylene-diamine. Before irradiation, oxygen was removed from the GQDs dispersion by purging with Ar. These conditions induced both chemical reduction as well as the incorporation of N atoms in the structure of GQDs. Thus, N-doped GQDs were produced. The morphology of dots was investigated using atomic force microscopy. UV-Vis and photoluminescence spectroscopy were used to investigate the optical properties of modified GQDs. The changes in the intensities of PL emission spectra were studied in the presence of different concentrations of Pd2+ and pesticide carbofuran. We observed promising results for the application of N-doped GQDs for non-enzymatic PL detection of selected metal ions and molecules of pesticide.
PB  - Szeged : University of Szeged
C3  - 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021
T1  - N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran
SP  - 143
EP  - 147
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5966
ER  - 

@conference{
author = "Dorontić, Slađana and Marković, Olivera S. and Kleut, Duška and Jovanović, Svetlana",
year = "2021",
abstract = "We produced Graphene Quantum Dots (GQDs) by electrochemical oxidation of graphite rods and exposed them to gamma irradiation at a dose of 200 kGy, in the presence of ethylene-diamine. Before irradiation, oxygen was removed from the GQDs dispersion by purging with Ar. These conditions induced both chemical reduction as well as the incorporation of N atoms in the structure of GQDs. Thus, N-doped GQDs were produced. The morphology of dots was investigated using atomic force microscopy. UV-Vis and photoluminescence spectroscopy were used to investigate the optical properties of modified GQDs. The changes in the intensities of PL emission spectra were studied in the presence of different concentrations of Pd2+ and pesticide carbofuran. We observed promising results for the application of N-doped GQDs for non-enzymatic PL detection of selected metal ions and molecules of pesticide.",
publisher = "Szeged : University of Szeged",
journal = "27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021",
title = "N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran",
pages = "143-147",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5966"
}

Dorontić, S., Marković, O. S., Kleut, D.,& Jovanović, S.. (2021). N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran. in 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021
Szeged : University of Szeged., 143-147.
https://hdl.handle.net/21.15107/rcub_cherry_5966

Dorontić S, Marković OS, Kleut D, Jovanović S. N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran. in 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021. 2021;:143-147.
https://hdl.handle.net/21.15107/rcub_cherry_5966 .

Dorontić, Slađana, Marković, Olivera S., Kleut, Duška, Jovanović, Svetlana, "N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran" in 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021 (2021):143-147,
https://hdl.handle.net/21.15107/rcub_cherry_5966 .

TY  - CONF
AU  - Dorontić, Slađana
AU  - Marković, Olivera S.
AU  - Kleut, Duška
AU  - Jovanović, Svetlana
PY  - 2021
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5967
AB  - Graphene quantum dots (GQDs) were fabricated by simple electrochemical oxidation of graphite electrodes. Modified GQDs were obtained by gamma irradiation of GQDs, EDA, and IPA mixture at a dose of 25 kGy. In this approach, GQDs with the amino groups were produced (25γ-GQDs). These GQDs have shown a high uniformity, good dispersibility in water, and strong photoluminescence in the blue part of the electromagnetic spectrum. Modified GQDs were studied in the optical detection of Co2+ ions. The PL intensities of GQDs were measured in the presence of Co2+ ions in the concentration range 0-7.5 μmol L-1. It was demonstrated that PL intensities decreased linearly in the concentration range 0-2.5 μmol L-1. The value of the coefficient of determination (R2= 0.95949) indicates the potential of 25γ-GQDs for application in optical sensing of Co2+ ions.
PB  - Szeged : University of Szeged
C3  - 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021
T1  - Amino functionalized graphene quantum dots - new fluorescent sensor for CO2+ ions
SP  - 107
EP  - 111
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5967
ER  - 

@conference{
author = "Dorontić, Slađana and Marković, Olivera S. and Kleut, Duška and Jovanović, Svetlana",
year = "2021",
abstract = "Graphene quantum dots (GQDs) were fabricated by simple electrochemical oxidation of graphite electrodes. Modified GQDs were obtained by gamma irradiation of GQDs, EDA, and IPA mixture at a dose of 25 kGy. In this approach, GQDs with the amino groups were produced (25γ-GQDs). These GQDs have shown a high uniformity, good dispersibility in water, and strong photoluminescence in the blue part of the electromagnetic spectrum. Modified GQDs were studied in the optical detection of Co2+ ions. The PL intensities of GQDs were measured in the presence of Co2+ ions in the concentration range 0-7.5 μmol L-1. It was demonstrated that PL intensities decreased linearly in the concentration range 0-2.5 μmol L-1. The value of the coefficient of determination (R2= 0.95949) indicates the potential of 25γ-GQDs for application in optical sensing of Co2+ ions.",
publisher = "Szeged : University of Szeged",
journal = "27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021",
title = "Amino functionalized graphene quantum dots - new fluorescent sensor for CO2+ ions",
pages = "107-111",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5967"
}

Dorontić, S., Marković, O. S., Kleut, D.,& Jovanović, S.. (2021). Amino functionalized graphene quantum dots - new fluorescent sensor for CO2+ ions. in 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021
Szeged : University of Szeged., 107-111.
https://hdl.handle.net/21.15107/rcub_cherry_5967

Dorontić S, Marković OS, Kleut D, Jovanović S. Amino functionalized graphene quantum dots - new fluorescent sensor for CO2+ ions. in 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021. 2021;:107-111.
https://hdl.handle.net/21.15107/rcub_cherry_5967 .

Dorontić, Slađana, Marković, Olivera S., Kleut, Duška, Jovanović, Svetlana, "Amino functionalized graphene quantum dots - new fluorescent sensor for CO2+ ions" in 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021 (2021):107-111,
https://hdl.handle.net/21.15107/rcub_cherry_5967 .

TY  - CONF
AU  - Мрђан, Горана
AU  - Вербић, Татјана
AU  - Марковић, Оливера С.
AU  - Ваштаг, Ђенђи
AU  - Апостолов, Сузана
AU  - Матијевић, Борко
PY  - 2021
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5965
AB  - Деривати карбохидразона представљају веома значај-
на једињења за проучавање с обзиром да многа од њих показују веома
изражену биолошку активност. Познавање јонизационог стања функци-
оналних група присутних у молекулу је од виталног значаја за разумева-
ње фармакокинетичких и фармакодинамичких особина новосинтетиса-
них једињења. Један од важнијих физичко-хемијских параметара, кисе-
линска константа (pKa), може да послужи као молекулски дескриптор за
повезивање односа стуктуре и активности једињења, што може укази-
вати на даљу потенцијалну примену новосинтетисаних деривата. У
овом раду, применом потенциометријске методе, одређене су киселин-
ске константе за тринаест синтетисаних једињења из серије монокарбо-
хидразона у циљу добијања информација о њиховим јонизационим ста-
њима при одређеним условима.
PB  - Бања Лука : Академија наука и умјетности Републике Српске
C3  - Међународни научни скуп Савремени материјали, Бања Лука, 2021.
T1  - Одређивање јонизационих константи одабраних деривата монокарбохидразона
VL  - 45
SP  - 415
EP  - 422
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5965
ER  - 

@conference{
author = "Мрђан, Горана and Вербић, Татјана and Марковић, Оливера С. and Ваштаг, Ђенђи and Апостолов, Сузана and Матијевић, Борко",
year = "2021",
abstract = "Деривати карбохидразона представљају веома значај-
на једињења за проучавање с обзиром да многа од њих показују веома
изражену биолошку активност. Познавање јонизационог стања функци-
оналних група присутних у молекулу је од виталног значаја за разумева-
ње фармакокинетичких и фармакодинамичких особина новосинтетиса-
них једињења. Један од важнијих физичко-хемијских параметара, кисе-
линска константа (pKa), може да послужи као молекулски дескриптор за
повезивање односа стуктуре и активности једињења, што може укази-
вати на даљу потенцијалну примену новосинтетисаних деривата. У
овом раду, применом потенциометријске методе, одређене су киселин-
ске константе за тринаест синтетисаних једињења из серије монокарбо-
хидразона у циљу добијања информација о њиховим јонизационим ста-
њима при одређеним условима.",
publisher = "Бања Лука : Академија наука и умјетности Републике Српске",
journal = "Међународни научни скуп Савремени материјали, Бања Лука, 2021.",
title = "Одређивање јонизационих константи одабраних деривата монокарбохидразона",
volume = "45",
pages = "415-422",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5965"
}

Мрђан, Г., Вербић, Т., Марковић, О. С., Ваштаг, Ђ., Апостолов, С.,& Матијевић, Б.. (2021). Одређивање јонизационих константи одабраних деривата монокарбохидразона. in Међународни научни скуп Савремени материјали, Бања Лука, 2021.
Бања Лука : Академија наука и умјетности Републике Српске., 45, 415-422.
https://hdl.handle.net/21.15107/rcub_cherry_5965

Мрђан Г, Вербић Т, Марковић ОС, Ваштаг Ђ, Апостолов С, Матијевић Б. Одређивање јонизационих константи одабраних деривата монокарбохидразона. in Међународни научни скуп Савремени материјали, Бања Лука, 2021.. 2021;45:415-422.
https://hdl.handle.net/21.15107/rcub_cherry_5965 .

Мрђан, Горана, Вербић, Татјана, Марковић, Оливера С., Ваштаг, Ђенђи, Апостолов, Сузана, Матијевић, Борко, "Одређивање јонизационих константи одабраних деривата монокарбохидразона" in Међународни научни скуп Савремени материјали, Бања Лука, 2021., 45 (2021):415-422,
https://hdl.handle.net/21.15107/rcub_cherry_5965 .

TY  - JOUR
AU  - Jovanović, Svetlana
AU  - Dorontić, Slađana
AU  - Jovanović, Dragana
AU  - Ciasca, Gabriele
AU  - Budimir, Milica D.
AU  - Bonasera, Aurelio
AU  - Scopelliti, Michelangelo
AU  - Marković, Olivera S.
AU  - Todorović Marković, Biljana
PY  - 2020
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5466
AB  - Due to the low consumption of chemicals, the absence of toxic residual side products, the procedure simplicity
and time-saving aspects, gamma irradiation offers advantages over the classical chemical protocols. We suc cessfully employed gamma irradiation in order to introduce N-atoms in Graphene Quantum Dots (GQDs). By
irradiating GQDs water dispersions in the presence of isopropyl alcohol and ethylenediamine, at doses of 25, 50
and 200 kGy, we attached amino groups onto GQDs in a single synthetic step. At the same time, a chemical
reduction is achieved, too. Selected conditions induced incorporation of N-atoms within GDQs atomic lattice
(around 3 at%), at all applied doses. Additionally, the C-atoms percentage was highly increased, from 63 to 79 at
% or higher. The zeta potential of dots changed from −34.6 to +9.1 mV, due to the modification of functio nalizing groups localized at the surface. Produced chemical changes lead to the desired alteration of the GQDs
optical properties, such as an increased photoluminescence intensity, a higher photoluminescence quantum
yields (from 2.07 to 18.40%) and a narrowing of the spectral features in the emission spectra. The ability of
gamma-irradiated GQDs to quench free radical species was investigated and positively assessed; additionally,
non-enzymatic optical detection of Cu(II) ions using GQDs as a sensor was studied and the detection limits are
herein reported. These results suggest that GQDs can be potentially applied as smart photoluminescent sensors
for metal cations.
PB  - Elsevier
T2  - Ceramics International
T1  - Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing
VL  - 46
SP  - 23611
EP  - 23622
DO  - 10.1016/j.ceramint.2020.06.133
ER  - 

@article{
author = "Jovanović, Svetlana and Dorontić, Slađana and Jovanović, Dragana and Ciasca, Gabriele and Budimir, Milica D. and Bonasera, Aurelio and Scopelliti, Michelangelo and Marković, Olivera S. and Todorović Marković, Biljana",
year = "2020",
abstract = "Due to the low consumption of chemicals, the absence of toxic residual side products, the procedure simplicity
and time-saving aspects, gamma irradiation offers advantages over the classical chemical protocols. We suc cessfully employed gamma irradiation in order to introduce N-atoms in Graphene Quantum Dots (GQDs). By
irradiating GQDs water dispersions in the presence of isopropyl alcohol and ethylenediamine, at doses of 25, 50
and 200 kGy, we attached amino groups onto GQDs in a single synthetic step. At the same time, a chemical
reduction is achieved, too. Selected conditions induced incorporation of N-atoms within GDQs atomic lattice
(around 3 at%), at all applied doses. Additionally, the C-atoms percentage was highly increased, from 63 to 79 at
% or higher. The zeta potential of dots changed from −34.6 to +9.1 mV, due to the modification of functio nalizing groups localized at the surface. Produced chemical changes lead to the desired alteration of the GQDs
optical properties, such as an increased photoluminescence intensity, a higher photoluminescence quantum
yields (from 2.07 to 18.40%) and a narrowing of the spectral features in the emission spectra. The ability of
gamma-irradiated GQDs to quench free radical species was investigated and positively assessed; additionally,
non-enzymatic optical detection of Cu(II) ions using GQDs as a sensor was studied and the detection limits are
herein reported. These results suggest that GQDs can be potentially applied as smart photoluminescent sensors
for metal cations.",
publisher = "Elsevier",
journal = "Ceramics International",
title = "Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing",
volume = "46",
pages = "23611-23622",
doi = "10.1016/j.ceramint.2020.06.133"
}

Jovanović, S., Dorontić, S., Jovanović, D., Ciasca, G., Budimir, M. D., Bonasera, A., Scopelliti, M., Marković, O. S.,& Todorović Marković, B.. (2020). Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing. in Ceramics International
Elsevier., 46, 23611-23622.
https://doi.org/10.1016/j.ceramint.2020.06.133

Jovanović S, Dorontić S, Jovanović D, Ciasca G, Budimir MD, Bonasera A, Scopelliti M, Marković OS, Todorović Marković B. Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing. in Ceramics International. 2020;46:23611-23622.
doi:10.1016/j.ceramint.2020.06.133 .

Jovanović, Svetlana, Dorontić, Slađana, Jovanović, Dragana, Ciasca, Gabriele, Budimir, Milica D., Bonasera, Aurelio, Scopelliti, Michelangelo, Marković, Olivera S., Todorović Marković, Biljana, "Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing" in Ceramics International, 46 (2020):23611-23622,
https://doi.org/10.1016/j.ceramint.2020.06.133 . .

TY  - CONF
AU  - Mrđan, Gorana
AU  - Verbić, Tatjana
AU  - Marković, Olivera S.
AU  - Matijević, Borko
AU  - Vaštag, Đenđi
AU  - Apostolov, Suzana
PY  - 2020
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5960
AB  - Carbohydrazone derivatives represent a very significant class of compounds due to their wide biological activity. Ionization states of functional groups present in the molecule are of vital importance for understanding of the pharmacokinetic and pharmacodynamic properties of the newly synthesized com-pounds.
One of the physicochemical parameters, the ionization constant (pKa), can be used as a molecular descriptor in order to relate structure and activity of a com-pound, which may indicate further potential application of newly synthesized deri-vatives.
In this work, ionization constants of twenty monocarbohydrazone deriva-tives were determined using potentiometric method, in order to obtain information about their ionization states under certain conditions.
C3  - XIII International Scientific Conference Contemporary Materials 2020  Programme  and the Book of Abstracts, Banja Luka, 11th September, 2020
T1  - Determination of ionization constants of selected monocarbohydrazone derivatives
SP  - 50
EP  - 50
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5960
ER  - 

@conference{
author = "Mrđan, Gorana and Verbić, Tatjana and Marković, Olivera S. and Matijević, Borko and Vaštag, Đenđi and Apostolov, Suzana",
year = "2020",
abstract = "Carbohydrazone derivatives represent a very significant class of compounds due to their wide biological activity. Ionization states of functional groups present in the molecule are of vital importance for understanding of the pharmacokinetic and pharmacodynamic properties of the newly synthesized com-pounds.
One of the physicochemical parameters, the ionization constant (pKa), can be used as a molecular descriptor in order to relate structure and activity of a com-pound, which may indicate further potential application of newly synthesized deri-vatives.
In this work, ionization constants of twenty monocarbohydrazone deriva-tives were determined using potentiometric method, in order to obtain information about their ionization states under certain conditions.",
journal = "XIII International Scientific Conference Contemporary Materials 2020  Programme  and the Book of Abstracts, Banja Luka, 11th September, 2020",
title = "Determination of ionization constants of selected monocarbohydrazone derivatives",
pages = "50-50",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5960"
}

Mrđan, G., Verbić, T., Marković, O. S., Matijević, B., Vaštag, Đ.,& Apostolov, S.. (2020). Determination of ionization constants of selected monocarbohydrazone derivatives. in XIII International Scientific Conference Contemporary Materials 2020  Programme  and the Book of Abstracts, Banja Luka, 11th September, 2020, 50-50.
https://hdl.handle.net/21.15107/rcub_cherry_5960

Mrđan G, Verbić T, Marković OS, Matijević B, Vaštag Đ, Apostolov S. Determination of ionization constants of selected monocarbohydrazone derivatives. in XIII International Scientific Conference Contemporary Materials 2020  Programme  and the Book of Abstracts, Banja Luka, 11th September, 2020. 2020;:50-50.
https://hdl.handle.net/21.15107/rcub_cherry_5960 .

Mrđan, Gorana, Verbić, Tatjana, Marković, Olivera S., Matijević, Borko, Vaštag, Đenđi, Apostolov, Suzana, "Determination of ionization constants of selected monocarbohydrazone derivatives" in XIII International Scientific Conference Contemporary Materials 2020  Programme  and the Book of Abstracts, Banja Luka, 11th September, 2020 (2020):50-50,
https://hdl.handle.net/21.15107/rcub_cherry_5960 .

TY  - CONF
AU  - Dorontić, Slađana
AU  - Marković, Olivera S.
AU  - Bonasera, Aurelio
AU  - Jovanović, Svetlana
PY  - 2020
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5961
AB  - Graphene Quantum Dots (GQDs) were produced using electrochemical oxidation of graphite rods. Obtained GQDs were gamma-irradiated in the presence of the N atoms source, ethylenediamine. Both structural and morphological changes were investigated using UV-Vis, X-ray photoelectron and photoluminescence (PL) spectroscopy as well as atomic force microscopy. The ability of both types of dots to change PL intensity in the presence of pesticides such as malathion and glyphosate, as well as copper (II) ions was detected. These preliminary results indicated a high potential of produced GQDs to be applied as non-enzymatic PL sensors for the detection of selected pesticides and metal ions.
PB  - Szeged : University of Szeged
C3  - The 26th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 23-24, 2020
T1  - Application of graphene quantum dots in heavy metals and pesticides detection
SP  - 179
EP  - 182
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5961
ER  - 

@conference{
author = "Dorontić, Slađana and Marković, Olivera S. and Bonasera, Aurelio and Jovanović, Svetlana",
year = "2020",
abstract = "Graphene Quantum Dots (GQDs) were produced using electrochemical oxidation of graphite rods. Obtained GQDs were gamma-irradiated in the presence of the N atoms source, ethylenediamine. Both structural and morphological changes were investigated using UV-Vis, X-ray photoelectron and photoluminescence (PL) spectroscopy as well as atomic force microscopy. The ability of both types of dots to change PL intensity in the presence of pesticides such as malathion and glyphosate, as well as copper (II) ions was detected. These preliminary results indicated a high potential of produced GQDs to be applied as non-enzymatic PL sensors for the detection of selected pesticides and metal ions.",
publisher = "Szeged : University of Szeged",
journal = "The 26th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 23-24, 2020",
title = "Application of graphene quantum dots in heavy metals and pesticides detection",
pages = "179-182",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5961"
}

Dorontić, S., Marković, O. S., Bonasera, A.,& Jovanović, S.. (2020). Application of graphene quantum dots in heavy metals and pesticides detection. in The 26th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 23-24, 2020
Szeged : University of Szeged., 179-182.
https://hdl.handle.net/21.15107/rcub_cherry_5961

Dorontić S, Marković OS, Bonasera A, Jovanović S. Application of graphene quantum dots in heavy metals and pesticides detection. in The 26th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 23-24, 2020. 2020;:179-182.
https://hdl.handle.net/21.15107/rcub_cherry_5961 .

Dorontić, Slađana, Marković, Olivera S., Bonasera, Aurelio, Jovanović, Svetlana, "Application of graphene quantum dots in heavy metals and pesticides detection" in The 26th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 23-24, 2020 (2020):179-182,
https://hdl.handle.net/21.15107/rcub_cherry_5961 .