PHARMACOKINETICS OF MEGESTROL ACETATE IN RABBITS AND RATS

The pharmacokinetics of megestrsl acetate(MA) was studied byRIA after iv or po administration in rabbits and rats. The bioavailability of MAwas 64% in rabbits, and 56% in rats. The study on metabolism in the livermicrosomal enzyme suggested that the formation of two polar metabolites. Theconcentration of radioactivity in the plasma of portal blood within 30 min afterintraduodenal administration of ~3H-MA exceeded that in peripheral venous blood,and a polar metabolite of MA was also present in portal blood.