Does binary blend emulsifier enhance emulsifier performance? Preparation of baicalin nanoemulsions using tea saponins and glycyrrhizic acid as binary blend emulsifier

This study aimed to compare the solubilization and emulsification abilities of tea saponins (TS), glycyrrhizic acid (GA), and their combination (the concentration ratio = 1:1, TS-GA). The solubilization capacities were quantified using molar solubilization ratio (MSR), and micelle-water partition coefficient (Km). To determine the emulsification, high shear-high pressure homogenization was used to prepare oil-in-water nanoemulsion (BI-NE) with baicalin (BI) as a model drug. Surfactant effects on emulsion formation and stability were studied by measuring particle size, zeta potential, and emulsion stability under different environmental conditions. In terms of solubilization, the order of MSR was TS > TS-GA > GA. And the MSR value of TS-GA is better than the calculated MSR. The nanoemulsions formed by all three had small particle size (<350 nm), absolute value of zeta potential (20–30 mV), and suitable turbidity. From stabilization, the binary blend emulsifier (TS-GA) exhibited superior ionic stability, remaining stable at ionic strength (0–300 mM NaCl). Nanoemulsions containing TS-GA were as stable at different temperatures (30–90 °C) and pH values (3–9) as TS and GA. The results show that the binary blend emulsifier (TS-GA) is an effective emulsifier that enhances the stability of BI-NE to a certain degree.