Preparation of Water-Soluble Solid Forms Containing Ursolic Acid Using Supercritical Fluid

In this work ursolic acid (UA), a poorly water-soluble compound, was inclusion complexed with 2-hydroxypropyl--cyclodextrin (HP--CD) by various methods such as kneading, solvent evaporation and two types of supercritical fluid processes. The solubility and characteristics of these UA/HP--CD complexes were investigated by scanning electron microscopy, x-ray diffraction and HPLC. The water solubilities of the two complexes obtained from solvent evaporation and ASES processes were observed to increase up to 6240 folds and 1256 folds, respectively, compared with that of unprocessed UA. The stability of UA/HP--CD complex samples in cosmetic formulations was examined at various temperatures for one month. The UA/HP--CD complex prepared by solvent evaporation was found to be most stable among all the cosmetic formulations tested in our experiments.