Pharmacokinetics and Biotransformation of Beraprost Sodium II : Absorption, Distribution and Excretion after Single Administration of Beraprost Sodium in Rat

Absorption, distribution and excretion of 3H-beraprost sodium were studied in rats. In situ absorption study showed that 3H-beraprost sodium was recadily absorbable from the small intestine. Beraprost sodium inhibited the gastric emptying of 14C-PEG. However, this effect may result in successive effusion of 3H-beraprost sodium from the stomach and rather contribute to the following maintenance of tissue and blood levels after p. o. dosing. The quantitative distribution studies in male rats suggested the possibility of extensive metabolism in the liver, and the following biliary excretion and enterohepatic circulation. Excretion in the urine and feces was rapid and almost complete after both p. o. and i. v. dosing to male and female rats. Irrespectively of dosing route, male rats excreted about 85% of the dose in the feces. whereas the female rats excreted near to a half of the dose in the urine. It therefore can be supposed that some sex difference is present in the biotransformation of beraprost sodium in rats. The elimination with the expired air, placental transfer, transfer to the suckling pups via the milk and melanin affinity were not signficant.