Evaluating Various Lactose Types as Solid Carriers for Improving Curcumin Solubility in Solid Self-Nanoemulsifying Drug Delivery Systems (S-SNEDDSs) for Oral Administration

Curcumin, a bioactive compound derived from turmeric, possesses numerous pharmaceutical properties; however, its poor aqueous solubility and permeability result in low bioavailability. This study aims to develop a solid self-nanoemulsifying drug delivery system (S-SNEDDS) using different lactose types as solid carriers for the oral administration of curcumin to enhance its solubility. The system comprised curcumin, an oil phase, and a surfactant. Jasmine oil, as the oil phase, and Cremophor® RH40, as the surfactant, were selected due to their superior ability to solubilize curcumin. A microemulsion was then prepared using a ternary phase diagram. The liquid SNEDDSs were converted into S-SNEDDSs by employing three solid carriers: Tablettose® 80, FlowLac® 100, and GranuLac® 200. Dissolution studies conducted in simulated gastric fluid demonstrated a significant improvement in curcumin solubility in the S-SNEDDS formulations compared to curcumin powder. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses confirmed the appearance of curcumin in the S-SNEDDS, while Fourier-transform infrared (FTIR) spectroscopy indicated compatibility between the excipients and curcumin. Additionally, an accelerated stability study conducted over four weeks at 40 °C and 75% relative humidity showed no significant changes in the physical appearance of the S-SNEDDS formulations. These findings suggest that the S-SNEDDS formulation effectively enhances curcumin’s solubility, potentially improving its bioavailability for oral administration.