Preparation, optimization, characterization and cytotoxicity in vitro of Baicalin-loaded mixed micelles

The aim of this study was to develop a Baicalin (BC)-loaded mixed micelle delivery system (BC-ST-P123-MMs) with sodium taurocholate (ST) and pluronic P123 block copolymer (P123) as carrier materials to improve the solubility of BC, a poorly soluble drug. In this study, the mixed micelle system was prepared using the method of thin-film dispersion and then optimized by the homogeneous design-response surface methodology with the entrapment efficiency and drug loading as indexes. The average size and the zeta potential of the BC-ST-P123-MMs were 15.60 nm and -5.26 mV, respectively. Drug loading (DL, 16.94%) and entrapment efficiency (EE, 90.67%) contributed to high solubility (10.20 mg/mL) of BC in water. The optimized BC-ST-P123-MMs appeared spherical with obvious core-shell structure and well dispersed without aggregation and adhesion under TEM. In addition, DSC result indicated that BC had been wrapped in BC-ST-P123-MMs and crystalline state of BC was changed. The release result in vitro showed that BC-ST-P123-MMs presented sustained release behavior compared to control group. The IC50 value of BC-ST-P123-MMs (46.18 μg/mL) was lower than that of BC solution (67.14 μg/mL) on Hep G2 cell lines. Cellular uptake tests illustrated that the ST-P123-MMs system as carrier could significantly enhance the uptake of drugs by tumor cells. The results demonstrated that the BC-loaded mixed micelles could improve solubility of BC and exhibited great potential for delivering drug into cancer cells.