Metabolism of Drugs. XLVII. Metabolic Fate of p-Hydroxybenzoic Acid and its Derivatives in Rabbit. (4)

Abstract

Metabolism of various alkyl p-hydroxybenzoates was investigated in rabbits using oral dose levels of 0.4 and 0.8 g./kg., and compared with than of p-hydroxybenzoic acid, which is a major metabolite of their esters. Metabolism of the esters was very rapid and excretion of the free p-hydroxybenzoic acid in the urine after administration was much less than that of p-hydroxybenzoic acid but output of the acid conjugated with glycine and glucuronic acid was much larger. When various alkyl esters were administered, those were converted into the free acid (25∼39%), glycine conjugate (15∼29%), ester-type glucuronide (5∼8%), ether-type glucuronide (10∼18%), and the sulfate (7∼12%) during 24 hours.