Development and optimization of a self micro-emulsifying drug delivery system (SMEDDS) for co-administration of sorafenib and curcumin.

In this study, we developed a novel co-administration of curcumin and sorafenib using a Self micro-emulsifying Drug Delivery System (SMEDDS) called Sorafenib-Curcumin Self micro-emulsifying Drug Delivery System (SOR-CUR-SMEDDS). The formulation was optimized using star point design-response surface methodology, and in vitro cellular experiments were conducted to evaluate the delivery ratio and anti-tumor efficacy of the curcumin and sorafenib combination. The SOR-CUR-SMEDDS exhibited a small size distribution of 13.48 ± 0.61 nm, low polydispersity index (PDI) of 0.228 ± 0.05, and negative zeta potential (ZP) of - 12.4 mV. The half maximal inhibitory concentration (IC) of the SOR-CUR-SMEDDS was 3-fold lower for curcumin and 5-fold lower for sorafenib against HepG2 cells (human hepatocellular carcinoma cells). Transmission electron microscopy (TEM) and particle size detection confirmed that the SOR-CUR-SMEDDS droplets were uniformly round and within the nano-emulsion particle size range of 10-20 nm. The SMEDDS were characterized then studied for drug release in vitro via dialysis membranes. Curcumin was released more completely in the combined delivery system, showing the largest in vitro drug release (79.20%) within 7 days in the medium, while the cumulative release rate of sorafenib in the release medium was low, reaching 58.96% on the 7 day. In vitro pharmacokinetic study, it demonstrated a significant increase in oral bioavailability of sorafenib (1239.88-fold) and curcumin (3.64-fold) when administered in the SMEDDS. These findings suggest that the SMEDDS formulation can greatly enhance drug solubility, improve drug absorption and prolong circulation in vivo, leading to increased oral bioavailability of sorafenib and curcumin.