Self-microemulsifying mouth dissolving film of felodipine: formulation, dispersion characteristics and enhanced bioavailability

The present study aimed to develop and evaluate a novel self-microemulsifying mouth dissolving film (SMMDF) of felodipine (FDP) to enhance its physicochemical properties and oral bioavailability. FDP, a poorly water-soluble BCS class II drug, exhibits low and variable bioavailability due to limited dissolution and extensive presystemic metabolism. The solubility of FDP was systematically determined in various lipid excipients, followed by screening of surfactants and co-surfactants for their self-emulsification efficiency. Based on these findings, liquid self-microemulsifying drug delivery system (SMEDDS) was developed and characterized for key physicochemical parameters. The optimized SMEDDS was subsequently incorporated into mouth-dissolving film via the solvent casting technique. Eleven batches of films were formulated employing central composite design. SMMDF was optimized considering critical quality attributes, including disintegration time, folding endurance, and percentage drug release. The liquid SMEDDS formulation was composed of Capryol 90, Kolliphor RH-40, and Transcutol P. The prepared SMMDF of FDP exhibited excellent physicochemical characteristics, with folding endurance exceeding 200 and rapid disintegration within 3 min. Solid-state characterization studies (DSC, XRD, and SEM) confirmed the amorphous dispersion of FDP within the polymeric matrix. In vitro dissolution release profiles proved significantly superior drug release from SMMDF compared to FDP suspension. In vivo studies revealed statistically significant improvement in pharmacokinetic parameters (p < 0.05) confirming enhanced systemic exposure from SMMDF. The enhanced performance is attributed to improved solubilization, nanosized dispersion, and increased dissolution of FDP from SMEDDS-based film system. Overall, the developed SMMDF represents a promising and patient-friendly approach for improving oral bioavailability of poorly water-soluble drugs.