Disposition kinetics, cytotoxicity and residues of fenvalerate in tissues following oral administration to goats

Disposition kinetics in goats of fenvalerate [(RS)-alpha-cyano-3-phenoxybenzyl (RS)-2-(4-chlorophenyl)-3-methylbutyrate] were studied after oral administration at 5 mg kg-1. The insecticide persisted in blood for up to 48 h. The V(d(area)), t(1/2(beta)), and t(1/2(Ka)) of fenvalerate were 12.14 (+/- 0.39) litre kg-1, 12.25 (+/- 0.25) h and 0.63 (+/- 0.11) h, while the AUC and Cl(B) values were respectively 7.35 (+/- 0.39) micrograms h ml-1 and 0.68 (+/- 0.04) litre kg-1 h-1. The residues in tissues reached a peak four days after insecticide administration and then started to decline. Maximum residue was found in the adrenal gland, followed by liver, kidney and intestine. Both GOT and GPT activities in kidney tissue, but only GPT activities in liver tissue had decreased significantly 4, 8 and 22 days post-administration. The fenvalerate did not produce any significant effects on serum acetylcholinesterase, cholesterol or protein levels in goats. Histopathological examination showed fatty changes in the periphery of lobule, congestion in sinusoid, haemolysis in central vein, necrosis and periportal fibrosis around the central vein of liver, and necrosis in kidney of fenvalerate-treated goats.