Lyophilized tablets of felodipine-loaded polymeric nanocapsules to enhance aqueous solubility: Formulation and optimization

The aim of this study was to enhance the physicochemical properties of felodipine through the formulation of lyophilized polymeric nanocapsule tablets. Felodipine was loaded into polymeric nanocapsules composed of Labrafac™ PG (oil solubilizer) and Eudragit® EPO (cationic coating polymer) using the sonoprecipitation technique. The effect of changing quantities of Labrafac™ PG (X1) and Eudragit® EPO (X2) on the mean particle size (Y1), zeta potential (Y2) and entrapment efficiency (Y3) were studied via 32 full factorial design. Both factors X1 and X2 had a significant effect on the mean particle size, while the zeta potential was affected by X2. The entrapment efficiency was affected significantly by X2 and by the interaction between both factors (X1X2). After purification by filtration and ultracentrifugation, the optimized formulation was incorporated into lyophilized tablets using poly (vinyl alcohol) as binder and stabilizer and either of two types of cryoprotectant (mannitol or sucrose). Different characterizations were performed on both types of lyophilized polymeric nanocapsule tablets, showing that each type exhibited porous structure, high-level drug content, rapid disintegration, and fast dissolution rate. Moreover, the saturation solubility for each type was vastly increased. The present study provides a unique formulation of high-level drug-loaded polymeric nanocapsules that could be efficiently incorporated in lyophilized tablets to remarkably enhance its stability and to improve the physicochemical properties of felodipine.