Formulation and Evaluation of a Self-Microemulsifying Drug Delivery System of Raloxifene with Improved Solubility and Oral Bioavailability

Poor aqueous solubility and dissolution limit the oral bioavailability of Biopharmaceutics Classification System (BCS) class II drugs. In this study, we aimed to improve raloxifene hydrochloride (RLX), a BCS drug, using self-microemulsifying drug delivery system (SMEDDS). Based on solubilities RLX, Capryol 90, Tween 80/Labrasol ALF, polyethylene glycol 400 (PEG-400) were selected as oil, surfactant mixture, cosurfactant, respectively. Pseudo-ternary phase diagrams constructed determine optimal composition (Capryol 90/Tween ALF/PEG-400 in 150/478.1/159.4/212.5 volume ratio) for RLX-SMEDDS with small droplet size (147.1 nm) stable microemulsification (PDI: 0.227). Differential scanning calorimetry powder X-ray diffraction lyophilized revealed loss crystallinity, suggesting molecularly dissolved or amorphous state RLX SMEDDS formulation. Moreover, exhibited significantly higher saturation rate water, simulated gastric fluid (pH 1.2), intestinal 6.8) than powder. Additionally, administration female rats resulted 1.94- 1.80-fold area under curve maximum plasma concentration, respectively, dispersion. Collectively, our findings suggest is promising formulation enhance therapeutic efficacy RLX.