The metabolism of antifertility steroids. The in virto metabolism of chlormadinone acetate.

Abstract

The isolation and identification of the major in vitro metabolites of chlormadinone acetate are reported. Human, rabbit, and rat liver incubations were employed in the isolation and identification, and male rat liver preparations were used to study the effect of phenobarbital stimulation on the formation of these metabolites. The metabolic pathway was influenced by the microsomal stimulating property of phenobarbital. 2alpha-hydroxychlormadinone was the major metabolite from the incubation of phenobarbital-stimulated rabbit and male rat liver. 17alpha-acetoxy-6-chloro-3beta-hydroxypregna-4,6-diene-20-one was the major metabolite from the incubation of unstimulated human and male rat liver. It was concluded that the 2alpha-hydroxychlormadinone acetate was demostrated only as a consequence of phenobarbital treatment.