BILIARY CEFPIRAMIDE EXCRETION - ITS RELATION TO BILIARY-EXCRETION OF BILE-ACIDS AND SULFOBROMOPHTHALEIN

Cefpiramide, a beta-lactam antibiotic, has been reported to be excrete d from hepatocytes into the bile by a carrier-mediated system. Herein, the relationship of biliary cefpiramide excretion to the excretion of bile acids and sulfobromophthalein was studied in rats. Biliary cefpi ramide excretion was markedly inhibited by sulfobromophthalein, lithoc holate-3-O-glucuronide and taurolithocholate-3-sulfate, whereas it was not inhibited by ursodeoxycholate or taurocholate. However, the inhib itory effect of cefpiramide on the biliary excretion of sulfobromophth alein or lithocholate-3-sulfate was very small. These findings indicat e that, although cefpiramide is excreted by a process common to organi c anions and bile acid sulfate and glucuronide, two or more excretory pathways for organic anions exist and cefpiramide has affinity for onl y one of these carriers.