Applying Biopharmaceutical Classification System criteria to predict the potential effect of Cremophor® RH 40 on fexofenadine bioavailability at higher doses.

Aim: To study the impact of various permeability enhancers on fexofenadine bioavailability. Furthermore, to predict the potential effect of Cremophor® RH 40 on fexofenadine pharmacokinetics at higher doses using Biopharmaceutical Classification System criteria. Experimental methods: The effect of the dose increase (60-360 mg) on the dissolution and permeability behavior of fexofenadine-Cremophor RH 40 formulations was studied in humans. The Biopharmaceutical Classification System criteria of the drug was determined. Results & conclusion: Cremophor RH 40 improved the dissolution and bioavailability of fexofenadine. The pharmacokinetics increased linearly with the dose increase. Absorption number (An) was significantly increased after addition of Cremophor RH 40 in comparison to an unprocessed drug. Similar An values were observed throughout the same dose range. The dose number (D0) values were <1 whereas, all the dissolution number (Dn) values were >1 at the same dose level.