Acidic hydrolysis of bromazepam studied by high performance liquid chromatography. Isolation and identification of its degradation products.
A kinetic study on the acidic hydrolysis of bromazepam was carried out in 0.01 M hydrochloric acid solution at 25 and 95 degrees C. A reversed-phase HPLC method was developed and validated for the determination of bromazepam and its degradation products. Bromazepam degraded by a consecutive reaction with a reversible first step. Two degradation products were isolated and identified by infrared, 1H and 13C nuclear magnetic resonance and mass spectroscopy. Spectroscopic data indicated that N-(4-bromo-2-(2-pyridylcarbonyl)phenyl)-2-aminoacetamide was the intermediate degradation product of this acid hydrolysis, whereas 2-amino-5-bromophenyl-2-pyridylmethanone was the final one. Therefore, the mechanism of this acid-catalysed hydrolysis involved initial cleavage of the 4,5-azomethine bond, followed by slow breakage of the 1,2-amide bond. Statistical evaluation of the HPLC method revealed its good linearity and reproducibility. Detection limits were 3.8 x 10(-7) M for bromazepam, 6.25 x 10(-7) M for the intermediate and 8.16 x 10(-7) M for the benzophenone derivative.
Panderi
I
I
Department of Pharmacy, University of Athens, Panepistimiopolis, Greece.
Archontaki
H
H
Gikas
E
E
Parissi-Poulou
M
M
D000081:Acetamides / Q000032:analysis*; D000818:Animals; D014151:Anti-Anxiety Agents / Q000032:analysis / Q000737:chemistry*; D001577:Benzophenones / Q000032:analysis*; D001960:Bromazepam / Q000032:analysis / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D006224:Cricetinae; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D008433:Mathematics; D008875:Middle Aged; D015394:Molecular Structure; D011725:Pyridines / Q000032:analysis*
C114283:2-amino-5-bromophenyl-2-pyridylmethanone; D000081:Acetamides; D014151:Anti-Anxiety Agents; D001577:Benzophenones; C114284:N-(4-bromo-2-(2-pyridylcarbonyl)phenyl)-2-aminoacetamide; D011725:Pyridines; C047723:benzophenone; D001960:Bromazepam