淫羊藿苷平衡溶解度和表观油水分配系数的测定

Determination of equilibrium solubility of icariin and its apparent oil/water partition coefficient

目的:测定淫羊藿苷的平衡溶解度及表观油水分配系数。方法:采用HPLC法测定了淫羊藿苷在水和各种有机溶剂中的平衡溶解度,采用摇瓶法测定了淫羊藿苷在正辛醇-水/缓冲盐溶液中的表观油水分配系数。结果:25℃下淫羊藿苷在水中的平衡溶解度为15.04mg/L,表观油水分配系数为77.31(logPapp=1.89);常用有机溶剂甲醇和乙醇对淫羊藿苷溶解性较好,分别为1 930.80mg/L和187.61mg/L。结论:淫羊藿苷的水溶性差,增大pH值可增加淫羊藿苷的溶解性,在正辛醇/pH7.4磷酸盐缓冲溶液中油水分配系数最大[113.14(logPapp=2.05)];水溶性差可能是影响淫羊藿苷肠吸收的原因之一。

Objective： To determine the equilibrium solubility of icariin and its partition coefficients for the n-octanolwater/buffer solution systems. Methods： A high performance liquid chromatography（HPLC） was established and used to detect the concentration of icariin in water and different organic solvents;the partition coefficients for the n-octanol-water/buffer solution systems of icariin were determined by shaking flask method. Results： The equilibrium solubility of icariin was 15.04 mg/L in water at 25℃,Papp of icariin was 77.31（log Papp=1.89） . The higher equilibrium solubility of icariin was 1930.80mg/L and 187.61mg/L in methanol and in ethanol respectively. Conclusions： The studies showed that icariin was not soluble and the higher pH can improve its equilibrium solubility. It has the highest partition coefficients in n-octanol/pH7.4 buffer solution system.Poor solubility of icariin may be one of the reasons resulting in its lower intestinal absorption.