Abstract
The metabolism of [14C] benfuracarb [2, 3-dihydro-2, 2-dimethyl-7-benzofuranyl N-[N-[2-(ethoxycarbonyl)ethyl]-N-isopropylsulfenamoyl]-N-methylcarbamate] was studied in houseflies 0.5, 2, 4 and 24hr after topical application. The penetration of [14C]benfuracarb was relatively rapid and 64.8% of the radioactivity was found in the internal fractions after 24hr. Benfuracarb was easily decomposed to form carbofuran which, in turn, was oxidized at the 3-position of the ring and the N-methyl group. These oxidized metabolites were then converted to conjugates. Major metabolites were carbofuran [2, 3-dihydro-2, 2-dimethyl-7-benzofuranyl methylcarbamate] and 3-hydroxy-carbofuran followed by N-hydroxymethyl-carbofuran, 3-keto-carbofuran, 3-hydroxy-carbofuran phenol, 3-hydroxy-N-hydroxymethyl-carbofuran and 3-keto-N-hydroxymethyl-carbofuran. Several minor metabolites were also detected. The appreciable amounts of carbofuran accumulated internally in the houseflies indicate its role as the toxic agent.
