熊果酸平衡溶解度和油水分配系数的测定

目的测定熊果酸的平衡溶解度及其在正辛醇-水中的表观油水分配系数,为设计熊果酸新剂型提供基础。方法采用HPLC测定熊果酸在不同pH介质、不同溶剂中的溶解度及熊果酸在正辛醇-水中的表观油水分配系数。结果 25℃下熊果酸在水中的平衡溶解度为5.64 mg.L 1,在pH 2.0~7.4的缓冲体系中,熊果酸的溶解度不受pH的影响。熊果酸在油中溶解度不佳,在表面活性剂及半极性溶剂中溶解度相对较好,在正辛醇-水体系中的油水分配系数1gP=2.17。结论熊果酸为溶解度小的亲脂性药物。

Determination of Equilibrium Solubility and Apparent Oil/Water Partition Coefficient of Ursolic Acid

OBJECTIVE To determine the equilibrium solubility of ursolic acid and its n-octanol-water system for designing new formulations. METHODS High performance liquid partition coefficients in the chromatography （HPLC） was established to determine the contents of ursolic acid in different pH solutions, differernt solvents and the partition coefficients for the n-octanol- water systems. RESULTS The equilibrium solubility of ursolic acid was 5.64 mg.L-1 in water at 25℃ and was not influenced by the pH of the buffer solution. The solubility of ursolic acid in oils was poor, but was relatively good in surfactants and Semi polar solvents. Partition coefficient of ursolic acid was 2.17 in n-octanol-water system. CONCLUSION Ursolic acid is a lioonhilic drug with little solubility property