Study on protolytic equilibria of lorazepam and oxazepam by UV and NMR spectroscopy
Abstract
Protolytic equilibria in homogeneous and heterogeneous systems of lorazepam and oxazepam, which are sparingly soluble ampholytes from the class of 1,4-benzodiazepines, were studied at 25 degreesC and ionic strength of 0.1 M. Acidity constants and equilibrium constants in a heterogeneous system were determined. On the basis of the analysis of the corresponding C-13- and H-1-NMR spectra, deprotonation site in the molecules of the investigated compounds was predicted. Finally, the correlation between chemical shifts in the H-1-NMR spectra and the acidity of the amide proton of 1,4-benzodiazepines was established. (C) 2003 Elsevier Science B.V. All rights reserved.
Keywords:
oxazepam / lorazepam / acidity constants / solubilitySource:
Journal of Pharmaceutical and Biomedical Analysis, 2003, 31, 4, 693-699Publisher:
- Pergamon-Elsevier Science Ltd, Oxford
DOI: 10.1016/S0731-7085(02)00686-6
ISSN: 0731-7085
PubMed: 12644196
WoS: 000181951300010
Scopus: 2-s2.0-0037467186
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Institution/Community
Hemijski fakultet / Faculty of ChemistryTY - JOUR AU - Popović, Gordana V. AU - Sladić, Dušan AU - Stefanovic, VM AU - Pfendt, Lidija B. PY - 2003 UR - https://cherry.chem.bg.ac.rs/handle/123456789/549 AB - Protolytic equilibria in homogeneous and heterogeneous systems of lorazepam and oxazepam, which are sparingly soluble ampholytes from the class of 1,4-benzodiazepines, were studied at 25 degreesC and ionic strength of 0.1 M. Acidity constants and equilibrium constants in a heterogeneous system were determined. On the basis of the analysis of the corresponding C-13- and H-1-NMR spectra, deprotonation site in the molecules of the investigated compounds was predicted. Finally, the correlation between chemical shifts in the H-1-NMR spectra and the acidity of the amide proton of 1,4-benzodiazepines was established. (C) 2003 Elsevier Science B.V. All rights reserved. PB - Pergamon-Elsevier Science Ltd, Oxford T2 - Journal of Pharmaceutical and Biomedical Analysis T1 - Study on protolytic equilibria of lorazepam and oxazepam by UV and NMR spectroscopy VL - 31 IS - 4 SP - 693 EP - 699 DO - 10.1016/S0731-7085(02)00686-6 ER -
@article{ author = "Popović, Gordana V. and Sladić, Dušan and Stefanovic, VM and Pfendt, Lidija B.", year = "2003", abstract = "Protolytic equilibria in homogeneous and heterogeneous systems of lorazepam and oxazepam, which are sparingly soluble ampholytes from the class of 1,4-benzodiazepines, were studied at 25 degreesC and ionic strength of 0.1 M. Acidity constants and equilibrium constants in a heterogeneous system were determined. On the basis of the analysis of the corresponding C-13- and H-1-NMR spectra, deprotonation site in the molecules of the investigated compounds was predicted. Finally, the correlation between chemical shifts in the H-1-NMR spectra and the acidity of the amide proton of 1,4-benzodiazepines was established. (C) 2003 Elsevier Science B.V. All rights reserved.", publisher = "Pergamon-Elsevier Science Ltd, Oxford", journal = "Journal of Pharmaceutical and Biomedical Analysis", title = "Study on protolytic equilibria of lorazepam and oxazepam by UV and NMR spectroscopy", volume = "31", number = "4", pages = "693-699", doi = "10.1016/S0731-7085(02)00686-6" }
Popović, G. V., Sladić, D., Stefanovic, V.,& Pfendt, L. B.. (2003). Study on protolytic equilibria of lorazepam and oxazepam by UV and NMR spectroscopy. in Journal of Pharmaceutical and Biomedical Analysis Pergamon-Elsevier Science Ltd, Oxford., 31(4), 693-699. https://doi.org/10.1016/S0731-7085(02)00686-6
Popović GV, Sladić D, Stefanovic V, Pfendt LB. Study on protolytic equilibria of lorazepam and oxazepam by UV and NMR spectroscopy. in Journal of Pharmaceutical and Biomedical Analysis. 2003;31(4):693-699. doi:10.1016/S0731-7085(02)00686-6 .
Popović, Gordana V., Sladić, Dušan, Stefanovic, VM, Pfendt, Lidija B., "Study on protolytic equilibria of lorazepam and oxazepam by UV and NMR spectroscopy" in Journal of Pharmaceutical and Biomedical Analysis, 31, no. 4 (2003):693-699, https://doi.org/10.1016/S0731-7085(02)00686-6 . .