The effect of dose form on the bioavailability of mebendazole in man.

Four different dose forms of mebendazole were administered to human volunteers, and urine was collected and assayed for mebendazole and unconjugated metabolites of mebendazole. Oral administration of mebendazole as an oily suspension slightly enhances the bioavailability of the drug, however mebendazole is not absorbed following rectal administration. The major urinary metabolite of mebendazole in humans is 2-amino-5(6)[alpha-hydroxybenzyl]benzimidazole (IV), not 2-amino-5(6) benzoylbenzimidazole (II), as previously reported.