Toxicokinetic Interactions of α-Cypermethrin and Chlorpyrifos in Rats
B. Wielgomas, J.Krechniak
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Department of Toxicology, Medical University of Gdańsk, Hallera 107, 80-416 Gdańsk, Poland
Pol. J. Environ. Stud. 2007;16(2):267–274
Preparations containing both organophosphates and pyrethroids are commonly used in insect control. Toxicokinetic interactions between α-Cypermethrin (CM ) and Chlorpyrifos (CPF) were studied in rats. The animals were given a solution of CM or CPF in rapeseed oil at a dose of 10 mg/kg and a mixture of CM and CPF at a dose of 5 mg/kg each by an intragastric tube once a day for 28 days. The concentrations of unchanged CM and CPF were determined in blood, liver and brain by GC-ECD. Also, the concentrations of CM and CPF were individually monitored in blood after administration of their single doses to calculate toxicokinetic parameters (Tmax., Cmax., AUC). In urine the main metabolites 3-(4-hydroxyphenoxy)benzoic acid (4OH3PBA) and 3,5,6-trichloro-2-pyridinol (TCP) were determined by HPLC in the rats treated daily with CM , CPF or their mixture. In the animals dosed with a single insecticide, the highest concentration of CM was found in blood and of CPF in liver. In the co-exposed rats, CPF decreased in all the tissues, while CM increased particularly in liver. The excretion of 4OH3PBA following CM administration increased significantly during the exposure period, whereas in the CPF-exposed rats, TCP was excreted at the same rate. Following the co-administration of both insecticides 4OH3PBA excretion decreased, but did not influence TCP excretion. In the coexposed animals, Cmax. and AUC increased for CM, and decreased for CPF.