Nutritional condition affects the disposition kinetics of albendazole in cattle

1. The influence of nutritional status on the plasma and abomasal fluid disposition kinetics of albendazole (ABZ) and its metabolites, albendazole sulphoxide (ABZSO) and albendazole sulphone (ABZSO2), has been investigated in the calf. 2. Free fatty acid (FFA) and beta-hydroxybutyrate (beta-OHB) serum concentrations were significantly higher in the feed-restricted (poor nutritional status) compared with control calf (optimal nutritional status). 3. ABZ parent drug was not detected in plasma at any time post-treatment and ABZSO and ABZSO2 were the metabolites detected in plasma. Both metabolites were rapidly depleted from the bloodstream. ABZ and its metabolites were recovered in abomasal fluid from 0.25 up to either 48 (ABZ) or 120h (ABZSO and ABZSO2) post-treatment. 4. The plasma disposition kinetics of both ABZ metabolites was significantly changed in the feed-restricted compared with control calf. ABZSO and ABZSO2 plasma area under the curves (AUCs) were significantly higher in the restricted animal. These enhanced AUCs correlated with significantly longer plasma half-lives (T1/2el) and mean residence times (MRTs) for these metabolites. 5. The delayed elimination of ABZ metabolites from the bloodstream correlated with the higher concentration of these molecules recovered in the abomasal fluid of the calves subjected to a dietary restriction. 6. The changes observed on disposition kinetics may reflect an impairment on the hepatic metabolism and clearance of ABZ as a consequence of FFA mobilization from adipose tissue and overproduction of ketone bodies in the liver.