METABOLISM OF TETRAMETHRIN ISOMERS IN RAT .1. IDENTIFICATION OF A SULFONIC-ACID TYPE OF CONJUGATE AND REDUCED METABOLITES

1. Urinary and faecal metabolites in rat treated with C-14-labelled (1RS, trans)tetramethrin [3,4,5,6-tetrahydrophthalimidomethyl (1RS, trans)-chrysanthemate] were identified using chromatographic techniques and spectroanalyses (nmr and ms). 2. 3-Hydroxy-cyclohexane-1,2-dicarboximide was found to be a major and unique urinary metabolite, reduced at the 1,2-double bond of the 3,4,5,6-tetrahydrophthalimide moiety. 3. The major faecal metabolites were sulphonic acid conjugates, having a sulphonic acid group incorporated into the double bond of the 3,4,5,6-tetrahydrophthalimide moiety. 4. On the basis of the metabolites identified here, the major biotransformation reactions of trans-tetramethrin in ran are: (1) cleavage of the ester linkage; (2) cleavage of the imide linkage; (3) hydroxylation of the cyclohexene or cyclohexane ring of the 3,4,5,6-tetrahydrophthalimide moiety; (4) oxidation at the methyl group of the isobutenyl moiety; (5) reduction at the 1,2-double bond of the 3,4,5,6-tetrahydrophthalimide moiety; and (6) incorporation of a sulphonic acid group into the 1,2-double bond of the 3,4,5,6-tetrahydrophthalimide moiety.