Metabolism of [4C]crufomate (4-t-butyl-2-chlorophenyl methyl methylphosphoramidate) by the sheep.

Twenty-five metabolites were isolated from the urine, feces or plasma of sheep given single oral doses of [14C]crufomate (4-t-butyl-2-chlorophenyl methyl methylphosphoramidate). These metabolites resulted from one or more of the following transformations: oxidatin of a methyl group in the t-butyl moiety to yield either an alcohol or a carboxylic acid; hydrolysis of the phosphate and phosphate and phosphoramidate bonds; oxidatin of the N-methyl group to yield N-formyl phosphoramidates; methylation of the N-formyl group to yield N-methyl-N-formyl phosphoramidates; oxidative N-demethylation; conjugation with glucuronic acid. No ring-hydroxylation of dechlorination was observed, and no crufonate was isolated from the urine, feces or plasma.