Determination of nitrazepam and its main metabolites in urine by thin-layer chromatography and direct densitometry.

T Inoue, T Niwaguchi

Index: J. Chromatogr. A. 339(1) , 163-9, (1985)

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Abstract

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.