Preparation, Characterization, and In vitro Evaluation of Curcumin- and Resveratrol-Loaded Solid Lipid Nanoparticles

Curcumin and resveratrol are natural compounds with significant anticancer activity; however, their bioavailability is limited due to poor solubility. This study aimed to overcome the solubility problem by means of solid lipid nanoparticles (SLN). 2-Hydroxypropyl -cyclodextrin (HPCD) was selected from a range of polymers based on miscibility and molecular interactions. SLNs were obtained by probe sonication and freeze-drying curcumin-resveratrol with/without HPCD incorporated in gelucire 50/13. SLNs were characterized by dynamic light scattering (DLS), zeta potential, powder X-ray diffractometry (PXRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and physical stability. The in vitro release of drugs from the SLNs was performed by the direct dispersion method and analyzed using a validated UV-visible method. In vitro efficacy was tested using a colorectal cancer cell line. Curcumin-resveratrol-gelucire 50/13-HPCD (CRG-CD) and curcumin-resveratrol-gelucire 50/13(CRG) SLNs showed a particle size from 100 to 150nm and were not in thecrystalline state per PXRD results. MDSC results complimented PXRD results by theabsence of melting endotherm of curcumin; TGA showed no weight loss, confirming theabsence of organic solvent residual, and the shape of the SLNs was confirmed as spherical by SEM. CRG SLNs were stable for 21days with respect to particle size and zeta potential. MTT assay indicated better IC50 value for CRG as compared to CRG-CD. Hence, novel SLNs of curcumin and resveratrol incorporated in gelucire 50/13 and HPCD were prepared and characterized to improve their bioavailability and anticancer activity.