Toxicokinetic of phenothrin in rabbits

The toxicokinetics of single dose phenothrin were examined in rabbits. For this aim, a total of 14 New Zealand breed, 2 to 2.5 kg body weight, 6 month-old female rabbits were used. The animals were divided into two groups and each group had 7 animals. Phenothrin was administered intravenously to each animal in group 1, at a dose of 10 mg/kg b.w. and orally to each of the animals in group 2 at the same dose. Dimethyl sulfoxide was used as a solvent in application of phenothrin. Plasma phenothrin levels were measured by gas chromatography equipped with an ECD detector. Toxicokinetic evaluations were made according to the plasma phenothrin level-time curve. Phenothrin was found to be distributed according to the two-compartment open model. The values ​​of elimination half-life (t1/2β), mean residence time (MRT) and area under the curve (AUC0→∞) after intravenous phenothrin administration were 2.57 ± 0.10 h, 2.79 ± 0.09 h and 6893.05 ± 261.26 ng/h/mL, respectively. On the other hand, the maximum plasma concentration (Cmax), time to reach Cmax (tmax), t1/2β, MRT and AUC0→∞ after oral administration were 185.71 ± 8.21 ng/mL, 1.21 ± 0.20 h, 4.24 ± 0.39 h, 6.65 ± 0.54 h and 1054.04 ± 65.90 ng/h/mL, respectively. The oral bioavailability of phenothrin was calculated as 15.29%. Mean residence time was short and oral bioavailability was low. This may be one of the reasons why phenothrin is included in safe pesticides.