The maternal-foetal distribution of thiabendazole administered in two different vehicles to pregnant mice

Abstract

We have compared the effects of two vehicles on the maternal-foetal distribution of 14C-thiabendazole ([ 14C]TBZ) given orally to Jcl: ICR mice on day 9 or 16 of gestation. TBZ, either suspended in olive oil (TBZ-O) or in a 0.5% aqueous solution of gum arabic (TBZ-G), was given orally on day 9 of gestation at a dose of 1 g/kg body weight (1 μCi/mouse). The mice were killed 0.5, 1, 3, 6, 12, 24 or 72 hr later. In mice treated with TBZ-O maximum levels of radioactivity in plasma and conceptuses were observed at 0.5 hr, whereas in those treated with TBZ-G maximum 14C levels were observed at 6 hr. The uptake of radioactivity from TBZ-O into the plasma and conceptuses was significantly higher than that from TBZ-G. Only trace levels of radioactivity were detected at 72 hr in both treatment groups. The placental transfer of [ 14C]TBZ was examined in mice treated with doses of 1 g/kg body weight (1 μCi/mouse) given as TBZ-O or TBZ-G on day 16 of gestation. The radioactivity in foetuses, placentas and maternal plasma was higher in mice treated with TBZ-O than those given TBZ-G. The placental transfer of [ 14C]TBZ was also examined by whole-body autoradiography in mice treated on day 16 of gestation.