Specific metabolic pathway in vitro of pinazepam and diazepam by liver microsomal enzymes of different animal species.

The metabolic pathway of Pinazepam and Diazepam in vitro was studied with rat, guinea pig and dog liver microsomes using a chromatographic and spectrophotometric technique. Two main pathways were observed, N1-dealkylation and C3-hydroxylation. N1-dealkylation was shown to be the predominant reaction for Pinazepam in all the animal species studied, while C3-hydroxylation was the major metabolic pathway for Diazepam in the rat. No oxazepam was found when Pinazepam and Diazepam were incubated with liver microsomes.