KINETICS OF ALBENDAZOLE AND ITS METABOLIT ES IN PLASMA AND ABOMASAL FLUIDS OF CATTLE

The kinetics of Albendazole (ABZ) and its metabolites in plasma and ab omasal fluid was studied, following the intraruminal administration of ABZ in calves. Jugular brood and abomasal fluid samples were taken ov er a 120 h period and were analyzed by HPLC for ABZ, Albendazole Sulph oxide (ABZSO) and Albendazole Sulphone (ABZSO(2)). While the ABZ paren t drug was not detected at any time post-treatment, ABZSO and were the metabolites recovered in plasma between 0.5 and 30-36 h post-treatmen t. The ABZ parent drug was detected up to 48 h in abomasal fluid; howe ver, ABZSO and ABZSO(2) metabolites were recovered in abomasum up to 1 20 h post-treatment. These results contribute to the understanding of the relationship between kinetic and clinical efficacy of benzimidazol e anthelmintics in cattle.