Published online by Cambridge University Press: 26 August 2015
The influence of diet type and pre-treatment fasting on the kinetic disposition of albendazole was evaluated in Sahiwal heifers following oral and intra-ruminal administration of the drug. The anthelmintically active moiety albendazole sulphoxide appeared early and was eliminated early in cattle offered green fodder, with decreased maximum concentration (C max) and area under concentration–time curve (AUC) when the drug was administered both through oral and intra-ruminal routes. Further, the elimination half-life (t ½β) revealed significantly increased values for albendazole sulphoxide in cattle administered albendazole through the intra-ruminal route. An increased AUC and t ½β is reflective of increased bioavailability of albendazole in animals offered dry fodder. Increased values (P < 0.05) of C max, time to C max (T max), AUC and t ½β for albendazole sulphoxide occurred in cattle with a pre-treatment 24-h fast, resulting in its increased bioavailability. Extrapolation of data of the active metabolite albendazole sulphoxide levels in terms of drug–parasite contact revealed increased exposure of parasites to the drug in cattle administered albendazole through the intra-ruminal route and with 24-h pre-treatment fasting.