Studies on the metabolism of oxazolam. II. Isolation and identification of the metabolites of oxazolam in rats.

^14C-Oxazolam (10-chloro-2, 3, 5, 6, 7, 11b-hexahydro-2-methyl-11b-phenylbenzo [6, 7]-1, 4-diazepino [5, 4-b]-oxazol-6-one), randomly labeled with 14C in the 11b-phenyl ring, was administered orally to the rat, and a number of metabolites were detected in the extracts of liver, kidney, brain, blood, urine and feces by thin-layer chromatography. Among those metabolites, N-desmethyl diazepam, oxazepam and 2-(2-hydroxy-n-propylamino)-acetylamino-5-chlorobenzophenone (PACB) were isolated from the liver extracts, 7-chloro-1, 3-dihydro-5-(4-hydroxyphenyl)-2H-1, 4-benzodiazepine-2-on (CDHB) from the bile, and 2-amino-5-chlorobenzophenone (ACB), 2-amino-5-chloro-3-hydroxybenzophenone (ACHB) and ACHB glucuronide from the urine. On the basis of these findings, a possible metabolic pathway of oxazolam was discussed.