Fabrication of baicalin solid dispersion using the supercritical anti-solvent technology: optimization, characterization, and evaluation

Baicalin is a flavonoid glycoside with substantial biological activity and pharmacological effects, primarily extracted from Scutellaria baicalensis Georgi. However, its clinical implementation has been impeded by suboptimal aqueous solubility and unfavorable bioavailability. This study employed a supercritical anti-solvent (SAS) process to prepare amorphous solid dispersions of baicalin, aiming to enhance its dissolution and bioavailability. The effects of supercritical temperature, supercritical pressure, and CO2 flow rate on encapsulation were thoroughly investigated using the Box-Behnken Design (BBD) response surface methodology. SEM, FTIR, DSC, and XRD analyses confirmed that the baicalin solid dispersion prepared via the SAS method was in an amorphous state. In vitro dissolution tests indicated that the solubility of baicalin in the solid dispersion was 9.4 times (pH = 6.8) greater than that of the raw baicalin particles. Furthermore, rat experiments revealed that the bioavailability of baicalin in the solid dispersions was 1.8 times higher than that in traditional particles. Notably, BASD exhibited strong inhibitory effects on the growth of Bacillus subtilis and Escherichia coli. Consequently, a solid dispersion of baicalin was successfully prepared using the BBD-optimized SAS process, significantly enhancing the performance of baicalin.