The absorption, excretion, and metabolism of chlorphenesin carbamate in the dog

Abstract

The absorption, excretion, and fate of orally administered chlorphenesin carbamate- 3H have been studied in the dog. The drug was well absorbed, with about 67–79 percent of a single oral dose of 100 mg kg appearing in the urine within 48 hr and only 4–12 per cent in the feces. Approximately 81 per cent of the urine radioactivity was present in neutral metabolites or their conjugates while 19 per cent of the radioactivity appeared as free or conjugated acidic metabolites. The major urinary metabolite in the dog, accounting for 59 per cent of the radioactivity in 0–12 hr and 32 per cent of the radioactivity in 12–48 hr, was a glucuronide of chlorphenesin carbamate. An additional 25 per cent of the radioactivity in urine was accounted for as the free drug or its sulfate conjugate. The major acidic metabolites in dog urine were p-chlorophenol, p-chlorophenoxylactic acid, and p-chlorophenoxyacetic acid. Several additional minor acidic and neutral metabolites also were isolated and characterized.