Improved dissolution of oleanolic acid with ternary solid dispersions.

The purpose of this study was to enhance the dissolution of oleanolic acid by solid dispersions consisting of the drug, a polymeric carrier, and a surfactant. Binary solid dispersions consisting of oleanolic acid and polyvinylpyrrolidone were prepared for comparison. Polysorbate 80, a nonionic surfactant, was incorporated into binary solid dispersions as the third component to prepare ternary solid dispersions. Solid dispersions were characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy, and dissolution tests. The crystallinization of OA was prohibited in solid dispersions. Both the binary and ternary solid dispersions enhanced the dissolution of OA. Moreover, the dissolution of ternary solid dispersion was faster compared with that of binary solid dispersion. Polysorbate 80 played an important positive role in dissolution of the solid dispersion.