Protolytic equlibria of bromazepam
Protolitičke ravnoteže bromazepama
Abstract
The protolytic equilibria of bromazepam, an ampholyte sparingly soluble in water, in homogeneous and heterogeneous systems were studied in the pH range 0–14 at 25ºC and at ionic strength of 0.1 mol/dm3 (NaCl). On the basis of 13C-NMR spectra, the protonation site was predicted – in acidic media the pyridine nitrogen of bormazepam is protonated. The acidity constants of bromazepam were determined spectrophotometrically (pKa1 2.83 and pKa2 11.60) and potentiometrically (pKa1 2.99). In the heterogeneous system the following equilibrium constants were determined: Ks0 =[HA](pKs0 3.44), Ks1 =[H2A+]/[H3O+](pKs1 0.61), and Ks2 =[A-][H3O+](pKs2 15.04).
Proučavane su protolitičke ravnoteže bromazepama, amfolita iz klase 1,4-benzodiazepina, slabo rastvornog u vodi. Ispitivanja su vršena u homogenom i heterogenom sistemu u pH intervalu 0–14, na temperaturi 25ºC i pri jonskoj sili 0,1 mol/dm3 (NaCl). Na osnovu 13C-NMR spektara pretpostavljeno je da do protonovanja u molekulu bromazepama dolazi na piridinskom atomu azota. Kiselinske konstante određene su spektrofotometrijski (pKa1 2.83 and pKa2 11.60) i potenciometrijski (pKa1 2,99). U heterogenom sistemu određene su sledeće ravnotežne konstante Ks0 =[HA](pKs0 3.44), Ks1=[H2A+]/[H3O+](pKs1 0.61), and Ks2 =[A-][H3O+](pKs2 15.04).
Keywords:
bromazepam / 1,4-benzodiazepines / acidity constants / heterogeneous equilibriaSource:
Journal of the Serbian Chemical Society, 2002, 67, 3, 187-195Publisher:
- Srpsko hemijsko društvo, Beograd
DOI: 10.2298/JSC0203187P
ISSN: 0352-5139
WoS: 000174611800005
Scopus: 2-s2.0-0036335136
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PharmacyTY - JOUR AU - Pfendt, Lidija AU - Popović, Gordana AU - Damjanović, Tatjana AU - Sladić, Dušan PY - 2002 UR - https://farfar.pharmacy.bg.ac.rs/handle/123456789/395 AB - The protolytic equilibria of bromazepam, an ampholyte sparingly soluble in water, in homogeneous and heterogeneous systems were studied in the pH range 0–14 at 25ºC and at ionic strength of 0.1 mol/dm3 (NaCl). On the basis of 13C-NMR spectra, the protonation site was predicted – in acidic media the pyridine nitrogen of bormazepam is protonated. The acidity constants of bromazepam were determined spectrophotometrically (pKa1 2.83 and pKa2 11.60) and potentiometrically (pKa1 2.99). In the heterogeneous system the following equilibrium constants were determined: Ks0 =[HA](pKs0 3.44), Ks1 =[H2A+]/[H3O+](pKs1 0.61), and Ks2 =[A-][H3O+](pKs2 15.04). AB - Proučavane su protolitičke ravnoteže bromazepama, amfolita iz klase 1,4-benzodiazepina, slabo rastvornog u vodi. Ispitivanja su vršena u homogenom i heterogenom sistemu u pH intervalu 0–14, na temperaturi 25ºC i pri jonskoj sili 0,1 mol/dm3 (NaCl). Na osnovu 13C-NMR spektara pretpostavljeno je da do protonovanja u molekulu bromazepama dolazi na piridinskom atomu azota. Kiselinske konstante određene su spektrofotometrijski (pKa1 2.83 and pKa2 11.60) i potenciometrijski (pKa1 2,99). U heterogenom sistemu određene su sledeće ravnotežne konstante Ks0 =[HA](pKs0 3.44), Ks1=[H2A+]/[H3O+](pKs1 0.61), and Ks2 =[A-][H3O+](pKs2 15.04). PB - Srpsko hemijsko društvo, Beograd T2 - Journal of the Serbian Chemical Society T1 - Protolytic equlibria of bromazepam T1 - Protolitičke ravnoteže bromazepama VL - 67 IS - 3 SP - 187 EP - 195 DO - 10.2298/JSC0203187P ER -
@article{ author = "Pfendt, Lidija and Popović, Gordana and Damjanović, Tatjana and Sladić, Dušan", year = "2002", abstract = "The protolytic equilibria of bromazepam, an ampholyte sparingly soluble in water, in homogeneous and heterogeneous systems were studied in the pH range 0–14 at 25ºC and at ionic strength of 0.1 mol/dm3 (NaCl). On the basis of 13C-NMR spectra, the protonation site was predicted – in acidic media the pyridine nitrogen of bormazepam is protonated. The acidity constants of bromazepam were determined spectrophotometrically (pKa1 2.83 and pKa2 11.60) and potentiometrically (pKa1 2.99). In the heterogeneous system the following equilibrium constants were determined: Ks0 =[HA](pKs0 3.44), Ks1 =[H2A+]/[H3O+](pKs1 0.61), and Ks2 =[A-][H3O+](pKs2 15.04)., Proučavane su protolitičke ravnoteže bromazepama, amfolita iz klase 1,4-benzodiazepina, slabo rastvornog u vodi. Ispitivanja su vršena u homogenom i heterogenom sistemu u pH intervalu 0–14, na temperaturi 25ºC i pri jonskoj sili 0,1 mol/dm3 (NaCl). Na osnovu 13C-NMR spektara pretpostavljeno je da do protonovanja u molekulu bromazepama dolazi na piridinskom atomu azota. Kiselinske konstante određene su spektrofotometrijski (pKa1 2.83 and pKa2 11.60) i potenciometrijski (pKa1 2,99). U heterogenom sistemu određene su sledeće ravnotežne konstante Ks0 =[HA](pKs0 3.44), Ks1=[H2A+]/[H3O+](pKs1 0.61), and Ks2 =[A-][H3O+](pKs2 15.04).", publisher = "Srpsko hemijsko društvo, Beograd", journal = "Journal of the Serbian Chemical Society", title = "Protolytic equlibria of bromazepam, Protolitičke ravnoteže bromazepama", volume = "67", number = "3", pages = "187-195", doi = "10.2298/JSC0203187P" }
Pfendt, L., Popović, G., Damjanović, T.,& Sladić, D.. (2002). Protolytic equlibria of bromazepam. in Journal of the Serbian Chemical Society Srpsko hemijsko društvo, Beograd., 67(3), 187-195. https://doi.org/10.2298/JSC0203187P
Pfendt L, Popović G, Damjanović T, Sladić D. Protolytic equlibria of bromazepam. in Journal of the Serbian Chemical Society. 2002;67(3):187-195. doi:10.2298/JSC0203187P .
Pfendt, Lidija, Popović, Gordana, Damjanović, Tatjana, Sladić, Dušan, "Protolytic equlibria of bromazepam" in Journal of the Serbian Chemical Society, 67, no. 3 (2002):187-195, https://doi.org/10.2298/JSC0203187P . .