Abstract
On single oral or subcutaneous administration of the alcohol- and acid-labeled preparations of [1R, trans]- and [1R, cis]-tetramethrin [3, 4, 5, 6-tetrahydrophthalimidomethyl (IRS, cis, trans-chrysanthemate] to both sexes of rats, the radiocarbon was rapidly and almost completely eliminated from the rat body. The radiocarbon residues in 20 to 21 tissues examined were generally very low. The trans-isomer showed somewhat more complete radiocarbon recovery and lower tissue residues than the cis-isomer. In addition, the acid-labeling showed slightly lower tissue residues, as compared with the alcohol-labeling. However, no significant differences in the total radiocarbon recovery and tissue residue levels between sexes or administration routes were found. Both [1R, trans]- and [1R, cis]-tetramethrin similarly underwent ester cleavage, reduction of the 1-2 bond of the alcohol moiety and oxidation at the isobutenyl group of the acid moiety and at the 2, 3, and 4-positions of the alcohol moiety. The metabolites produced via these reactions were in part conjugated with glucuronic acid. The major metabolites from the acid moiety of both isomers were the oxidized derivatives of chrysanthemic acid at the trans methyl of the isobutenyl group. Also, the major metabolites from the alcohol moiety of both isomers were the cyclohexanedicarboximide derivatives oxidized at the 2, 3 and 4-positions. However, the relative amount of the identified metabolites differed in the two both isomers. There were no remarkable differences in the nature and amounts of metabolites between either dose routes or sexes.
