The distribution and elimination of radioactivity in the rat after administration of 14C-4-acetamidophenyl-2-acetoxybenzoate (benorylate)

Abstract

Following oral administration of 4-acetamido-phenyl-2-acetoxybenzoate (carboxyl-14C) (benorylate) to rats, no gross differences were detected 7.5 h after administration with respect to the distribution of 14C in various tissues, including the upper sections of the small intestine. A high concentration of 14C was found in the lower sections of the intestine 4 h after administration. The 14C in the intestine was present as unchanged benorylate, as detected by thin-layer chromatography, suggesting that benorylate absorption was slow. Intravenous injection of 14C-benorylate to rats showed that the drug had a relatively high elimination rate from the blood with a half-life of 1.9 h. In blood benorylate must be rapidly hydrolysed enzymatically since no 14C-metabolites, other than salicylic acid, could be detected.