Abstract
In guinea pigs, chlorphenesin carbamate (CPC), a centrally acting skeletal muscle relaxant, was excreted rapidly in urine after oral administration of the 14C-labeled compound. During 5 days, about 93% of the dose administered was recovered from urine and only 2% appeared in feces. The glucuronide of CPC was the major metabolite which accounted for about 87% of the total radioactivity excreted in 48 hr urine and only 2.5% of the urinary radioactivity was excreted as the acidic metabolites including p-chlorophenoxylactic acid, p-chlorophenoxyacetic acid and p-chlorophenol. The biliary excretion of CPC after intravenous administration was less than 10% of the dose administered in guinea pigs, while it was about 42% in rats. The major metabolite found in the bile was the glucuronide in both species. In common bile duct-ligated rats, CPC markedly inhibited the spinal reflex but duration of the action was shorter than that in intact rats. A temporary rise of radioactivity, followed by rapid fall in blood and rapid excretion in urine were observed by the ligation of common bile duct after administration of 14C-CPC, as compared to those in intact rats. CPC was excreted mostly as its glucuronide and the excretion of acidic metabolites decreased markedly in these bile duct-ligated rats. Urinary acidic metabolites increased to a greater extent after oral administration than by a subcutaneous route.
