Abstract
Concentrations of albendazole sulphoxide and its sulphone metabolite in plasma in cattle and buffalo were measured by high-performance liquid chromatography after single and divided intraruminal administration of albendazole at the recommended nematocidal and fasciolicidal dose rates of 7.5 and 15.0 mg/kg body weight, respectively. No significant differences in the plasma concentrations of the metabolites or their pharmacokinetic parameters were observed between cattle or buffalo at either dose rate. Pharmacokinetic analysis and the disposition curve of the metabolites indicated increased uptake of the drug in both cattle and buffalo when the same total amount of the drug was given in divided doses compared to a single dose (p < 0.05). The divided dose schedules of administration could possibly be exploited to extend the life of the available benzimidazole anthelmintics.