Distribution of thiabendazole (TBZ) in pregnant mice.

Abstract

Thiabendazole (TBZ) suspended in olive oil or 3% gum arabic was given orally to pregnant ICR mice on day 15 (a single administration group) or during days 6 to 15 (repetitive administration group) of gestation at dose levels of 700, 350 and 100 mg/kg/d and TBZ in the liver, placenta and fetus of mice was analyzed by means of gas chromatography with FPD at 12 and 24 h after final administration. TBZ was transferred to the fetus from the placenta in maternal mice treated with TBZ and the concentration of TBZ in the organs increased with an increase in dose level. TBZ and its metabolite, 5-hydroxythiabendazole (5-OH TBZ, including glucuronide and sulfate of it), in the blood, liver, kidney, placenta and fetus of mice treated with 700 mg/kg/d of TBZ were analyzed by means of fluorometry at 1, 2, 6, 12, 24, 48 and 120 h after final dose. The time course of concentration of TBZ and 5-OH TBZ in the liver, kidney, placenta and fetus showed a similar pattern to that in the blood. The maximum concentration of TBZ in repetitive administration group was observed at 1 h after final dose and was no difference between those in two vehicles, whereas in a single administration group the maximum concentration in TBZ-olive oil group at 1 h was higher than that in TBZ-gum arabic group at 1 or 2 h. The concentration of 5-OH TBZ in repetitive administration group was higer than that in a single administration group within 12 h after final dose in both different vehicles.