INFLUENCE OF SURFACTANTS ON ORAL BIOAVAILABILITY OF ALBENDAZOLE BASEDON THE FORMATION OF THE SULFOXIDE METABOLITES IN RATS

The influence of two surfactants, sodium taurocholate (STC) and polyso rbate 80 (P80), on the bioavailability of albendazole (ABZ), orally ad ministered to rats, has been studied. To assess the effect of the surf actants, they were administered at critical micellar and supramicellar concentrations, 5 and 10 mM for STC and 0.0022 and 0.22% for P80, alo ng with a subclinical dose of 5 mg kg(-1) of ABZ. Doses of 5 and 10.6 mg kg(-1) ABZ were also administered as controls. The results show an increase in the sulphoxide AUC values: 55% in the STC 5 mM and 88% in the STC 10 mM and P80 0.0022% treatments when compared to the control ABZ 5 mg kg(-1) dose. MRT values also show longer-lasting plasma alben dazole sulphoxide concentration following these three treatments, part icularly for the P80 0.0022% treatment. While there was no change in t he apparent rate of formation of ABZSO, the amount of ABZSO formed was increased significantly by the addition of surfactants (STC 10 mM and P80 0.0022%). (C) 1998 John Wiley & Sons, Ltd.