THE BIOAVAILABILITY OF FEBANTEL IN DEHYDRATED CAMELS

In the present study the bioavailability of febantel paste and febante l suspension was investigated in the fully hydrated and the dehydrated camel, The serum concentrations of febantel and its metabolites, fenb endazole, oxfendazole and fenbendazole sulfone were determined by high performance liquid chromatography following extraction with ether, Th e exposure to febantel and its metabolites in fully hydrated camels wa s significantly higher in camels dosed with febantel paste compared to febantel suspension, as measured by AUC and C-max. The AUC and C-max of fenbendazole and oxfendazole were significantly lower in dehydrated camels as compared to control camels dosed with febantel paste. The s ystemic availability of febantel suspension in control and dehydrated camels was very low and differences between dehydration and control ph ases were insignificant. The low systemic availability of febantel in camels dosed with febantel suspension may cause nematodes to become re sistant to this anthelmintic, It is, thus, suggested to increase the d ose of febantel paste in dehydrated camels in order to increase the ex posure to febantel and its metabolites. The binding of febantel, fenbe ndazole, oxfendazole and fenbendazole sulfone to camels' serum protein s was over 85%, Oxfendazole was only about 70% bound, Dehydration of 1 0 days did not affect the binding of these benzimidazole derivatives t o serum proteins.