Metabolism and distribution of fenvalerate mixed with phoxim in mice

Objective: To investigate the metabolism and distribution of fenvalerate mixed with phoxim in mice. Methods: Using 14C-Fenvalerate as tracing agent, a single dose of mixed insecticide was given intravenously to mice. During 0.5 to 120 min after the administration, nine blood samples were taken for measurement. Eight samples from brain, heart, liver and lung were also taken respectively during 8 to 960 min. The samples were measured by β-scintillation counter and expressed as ng/ml blood or ng/g tissue.The data of blood samples were analyzed by residual method for the estimation of toxicokinetic parameters. Results: The toxicokinetics of fenvalerate mixed phoxim was fitted to the two-compartment model with distribution phase T1/2α of 2.7 min, elimination phase T1/2β of 106.6 min and apparent volume of distribution of 2.9 L/kg. The k12(0.17 min-1) was greater than k21(0.077 min-1). The highest concentration of fenvalerate residues was found in the lung, followed by the liver, heart and brain. Conclusion: The lung is involved in fenvalerate metabolism which suggested the importance of pulmonal toxicity induced by the insecticide