Lipid nanoparticles for oral delivery of raloxifene: optimization, stability, in vivo evaluation and uptake mechanism.

Raloxifene HCl (RLX) shows low oral bioavailability (<2%) in humans due to poor aqueous solubility and extensive (>90%) metabolism in gut. Lipid nanoparticles (SLN) with glyceryl tribehenate were designed to enhance drug's oral bioavailability. Box-Bhenken design was used to optimize manufacturing conditions. Optimized SLN had particle size of 167±3nm and high encapsulation efficiency (>92%). Oral bioavailability of RLX from SLN was improved by 3.24 folds compared to free RLX in female Wistar rats. Both clathrin and caveolae mediated endocytosis pathways were involved in the uptake of SLN. Lymphatic transport inhibitor, cycloheximide significantly reduced oral bioavailability of SLN.