| Abstract: | Capillary gas-liquid chromatographic analysis of seven commercial samples of bioresmethrin [5-benzyl-3-furylmethyl (1R)-trans-chrysanthemate] demonstrated that each contained toxicologically significant amounts (1-5%) of the (1R)-cis-isomer (cismethrin) as an impurity. Intravenous injection of the labelled compounds to rats indicated that the concentrated solutions of these compounds may precipitate in the blood and subsequently become trapped in the lung. Slow release of the toxic isomer impurity probably accounts for the delay in appearance of symptoms after intravenous administration of impure bioresmethrin. Similarly, higher doses of cismethrin can be tolerated when concentrated solutions are administered intravenously. |
