穿山龙薯蓣皂苷平衡溶解度及表观油水分配系数的测定

Determination of dioscin equilibrium solubility and apparent oil-water partition coefficient

目的考察穿山龙薯蓣皂苷的平衡溶解度及表观油水分配系数,为后续制备新型口服纳米制剂研究奠定基础。方法采用HPLC法测定穿山龙薯蓣皂苷在水中以及在模拟人胃肠道不同肠段的不同pH值的磷酸盐缓冲溶液中的平衡溶解度,采用摇瓶法和HPLC法相结合的方法测定穿山龙薯蓣皂苷的表观油水分配系数。结果穿山龙薯蓣皂苷在水中的平衡溶解度为0.2038μg·mL^(-1);在模拟人胃肠道不同肠段的pH值的磷酸盐缓冲溶液中,当pH=7.8~8.0时,穿山龙薯蓣皂苷的平衡溶解度最大,为4.1163μg·mL^(-1);当pH=5.0时,穿山龙薯蓣皂苷的平衡溶解度最小,为2.4154μg·mL^(-1)。穿山龙薯蓣皂苷的表观油水分配系数在不同pH条件下均大于零。结论穿山龙薯蓣皂苷的水溶性较差,而其在人胃肠道生理条件下,它的脂溶性相对较好。因此后续课题可通过改善其溶解度来提高穿山龙薯蓣皂苷的口服生物利用度,进而研究穿山龙薯蓣皂苷的口服新剂型。

Objective To determine the equilibrium solubility of dioscin and apparent oil-water partition coefficient, and lay the foundation for further study on preparation of novel oral nano preparation. Methods HPLC was used to determine the quilibrium solubility of dioscin in water and in phosphate buffer solution at different pH values. Apparent oil-water partition coefficient of dioscin was determined by shake flask method and HPLC. Results The equilibrium solubility of dioscin in water was for 0.2038 μg·mL^（-1）; In phosphate buffer solution in simulated human gastrointestinal tract with different pH value, when pH was 7.8-8.0, the equilibrium solubility of dioscin was 4.1163 μg·mL^（-1）; when pH = 5.0, the equilibrium solubility of dioscin was the minimal at 2.4154 μg·mL^（-1）. The oil-water partition coefficient of dioscin in different pH conditions were all greater than zero. Conclusion Dioscin shows poor water solubility, while in the gastrointestinal tract under physiological conditions, its fat solublility is relatively good. Future research can focus on improving its solubility to improve the oral bioavailability of dioscin to obtain a new oral preparation of dioscin.