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(442) Pyrethroids: Update on toxicokinetics, neurotoxicity and induction of microsomal biotransformation; their implications on risk assessment. Martinez, Maria1, Martinez, M.1, Díaz, M.1, Frejo, M.1, Fernández, R.1, Morales, M.1, Martinez-Larrañaga, M.1, Anadon, A.1, 1 ABSTRACT- Synthetic Key words: Pyrethroids, toxicokinetics, neurotoxicity, P450 induction |
-cyano pyrethroids are increasingly used for numerous applications, varying from plant protection to general pest control, because of they are characterized by high toxicity to insects whereas their mammalian toxicity is considerably lower compared with other pesticides. Nevertheless, following overexposure to pyrethroids a variety of human health effects such as dizziness, nausea, loss of appetite, headache and paresthesia have been reported. An objective evaluation of these symptoms as well as other potential health effects caused by pyrethroid exposure is only possible if individual internal exposure is known. This paper presents recent data of deltamethrin, cyfluthrin and cyhalothrin from kinetic studies including bioavailability, tissue distribution and elimination, metabolism as well as neurotoxicity assays in an animal model, male Wistar rat. For deltamethrin and cyhalothrin, the elimination half-lives (t
) from plasma were 33 h and 8 h for i.v. and 38 h and 10 h for oral administration, respectively. The oral bioavailability of deltamethrin (26 mg/kg) and cyhalothrin (20 mg/kg) was found to be 14% and 71%. Considerable concentrations of deltamethrin and cyhalothrin were found in brain. The t