Design and preparation of controlled floating gastroretentive delivery systems for enhanced fexofenadine hydrochloride oral bioavailability

Abstract

Purpose: To design and prepare effervescent floating gastroretentive tablets for controlled fexofenadine hydrochloride (HCl) release and enhanced oral bioavailability. Method: Various tablet formulations of the drug were prepared by direct compression. A systematic approach in the design of the formulations was adopted, where, first, formulations consisting of single polymers with a high polymer: sodium bicarbonate ratio were investigated for its physicochemical properties (in-vitro floating behaviour, drug release profile, etc). Next, improvement of tablets’ properties was achieved by decreasing polymer: sodium bicarbonate ratio. Subsequently, a final optimization step involved blending polymers at different polymer: polymer ratios. The formulations were evaluated in vitro and in vivo in albino rabbits Results: The formulation consisting of hydroxypropyl methylcellulose K15M/hydroxypropyl methylcellulose K100LV at 1: 2 ratio (F8) showed good floating properties (14 s floating lag time) with nearly zero order controlled drug release for 24 h (R2 = 0.9876). In-vivo bioavailability studies of F8 in albino rabbits showed a significant increase in area under the curve (AUC, 134 %, p < 0.05) and hence an improvement in its oral bioavailability, compared to a commercial conventional product. Conclusion: The good quality of the effervescent floating gastroretentive tablets of fexofenadine HCl developed is an indication that the approach used is suitable for the formulation of the drug for controlled drug release and enhanced oral bioavailabiliy.