Determination of nitrazepam and its main metabolites in urine by thin-layer chromatography and direct densitometry.
A method for the direct quantitative densitometry of nitrazepam and its main metabolites (7-aminonitrazepam, 7-acetamidonitrazepam and 2-amino-5-nitrobenzophenone) in urine was developed. The unchanged drug and its metabolites were extracted with benzene-dichloromethane (4:1), subjected to thin-layer chromatography, and determined by direct ultraviolet densitometry. Recovery experiments showed that the method was quantitative. The limit of detection was 5 ng/ml for 2-amino-5-nitrobenzophenone and 10 ng/ml for other compounds. The method was applied to the determination of nitrazepam and its metabolites excreted in human urine after administration of 10 mg of the drug.
D000328:Adult; D001577:Benzophenones / Q000652:urine; D002855:Chromatography, Thin Layer; D003720:Densitometry; D005260:Female; D006801:Humans; D008297:Male; D009567:Nitrazepam / Q000031:analogs & derivatives / Q000652:urine*; D013056:Spectrophotometry, Ultraviolet
D001577:Benzophenones; C045948:2-amino-5-nitrobenzophenone; C043577:7-aminonitrazepam; C043576:7-acetamidonitrazepam; D009567:Nitrazepam