Metabolism of levorotary 4,5-dihydrodiazepam in the rat.

The metabolism of (-)-4,5-dihydrodiazepam (7-chloro-1,3,4,5-tetrahydro-1-methyl-5-phenyl-2H-1,4-benzo[2-14C]diazepin-2-one) (I) was investigated in rats. Metabolites from urine and bile extracts purified by thin-layer chromatography were identified by mass spectrometry. Diazepam and its main metabolites were found among the biotransformation products of I. Based on these findings, the most important identified metabolic route of the compound studied appears to be the formation of an unsaturated bond between the N4 and C5 atoms, and further transformation of the diazepam formed.