Disposition of trilostane in the rat and monkey

The metabolism of trilostane, a novel inhibitor of adrenal steroidogenesis, was studied in the rat and monkey. In the rat, a peak blood level, equivalent to 2 microgram/ml of trilostane, was observed following a 25 mg/kg oral dose; excretion was mainly via the feces. In the monkey, the peak plasma level, equivalent to 15 microgram/ml, was observed 2 hr after a 20 mg/kg oral dose; elimination of radioactivity was predominantly in the urine. The five major metabolites of trilostane in monkey urine have been isolated and partially characterized. The primary metabolic pathways involved hydroxylation and glucuronide formation.