| Abstract: | Camazepam [3-(N,N-dimethyl)carbamoyloxy-7-chloro-1-methyl-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-2-one, CMZ] possesses anxiolytic, anticonvulsant, muscle relaxant and hypnotic properties. CMZ is clinically used as a racemate. The enantioselective metabolism of racemic CMZ by rat liver microsomes was studied. Major metabolites were isolated by normal-phase and reversed-phase liquid chromatography (LC) and further characterized by UV absorption, mass, and circular dichroism spectral analyses, and by chiral stationary phase LC analysis. Following anin vitro incubation of rac-CMZ, the unmetabolized CMZ was found to be enriched in the (S)-CMZ, indicating that the Renantiomer was enantioselectively metabolized. Two of the most abundant metabolites, formed by hydroxylation and demethylation of a methyl group of theN,N-dimethylcarbamyloxy side chain, were found to be enriched in the Renantiomer. The results indicated that the (R)-CMZ was metabolized at a faster rate than (S)-CMZ by rat liver microsomes. |
