Preparation and characterisation of a solid self-microemulsifying drug delivery system containing fexofenadine hydrochloride

Abstract

Fexofenadine hydrochloride (FH) is a second-generation antihistamine that selectively antagonizes peripheral H1 receptors and is used in the treatment of seasonal allergic rhinitis and chronic idiopathic urticaria. FH belongs to the BCS Class IV, characterized by poor solubility and limited permeability. As a substrate of P-glycoprotein, FH undergoes efflux in the intestinal lumen, further reducing its absorption and oral bioavailability (33%). A self-microemulsifying drug delivery system (SMEDDS) was selected to overcome these limitations. The aim of this study was to develop a SMEDDS formulation to enhance the solubility of FH. SMEDDS containing fexofenadine hydrochloride (SMEDDS-FH) employed Dubcare GPE 810, Tween 20, and Transcutol HP at a ratio of 20:20:60 (w/w), containing 12.28% FH. The formulation exhibited stability in various dispersion media, thermodynamic stability, and achieved a mean droplet size and zeta potential of 47.17 nm and +19.6 mV. SMEDDS-FH was solidified (SSMEDDS-FH) by adsorption onto Florite R. SMEDDS-FH, S‑SMEDDS‑FH, and the reference tablet all exhibited drug release above 85% within 10 minutes. The SMEDDS-FH and S-SMEDDS-FH formulations met the criteria of SMEDDS, demonstrating potential for improving the oral bioavailability of fexofenadine hydrochloride.