水飞蓟素平衡溶解度及表观油水分配系数的测定

Determination of equilibrium solubility and apparent oil/water partition coefficient of silymarin

目的考察水飞蓟素在37℃下,在不同pH磷酸盐缓冲溶液中的平衡溶解度和表观油水分配系数。方法采用气浴恒温振荡器摇瓶法测定水飞蓟素的平衡溶解度及表观油水分配系数,紫外-可见分光光度法测定水飞蓟素在正辛醇-缓冲体系的质量浓度。结果 37℃时,水飞蓟素在pH 2.0、3.0、4.0、5.0、6.0、6.8、7.4、8.0、9.0的磷酸盐缓冲液中的平衡溶解度分别为0.673、0.681、0.776、0.848、0.937、1.218、1.486、1.504、1.691 mg.mL-1,相应条件下的表观油水分配系数分别为57.12、10.83、15.56、7.39、10.19、3.82、2.75、1.79、0.84。结论水飞蓟素在磷酸盐缓冲溶液中的平衡溶解度及表观油水分配系数与介质的pH值相关,介质的pH值增大,水飞蓟素平衡溶解度增大,表观油水分配系数减小。

Objective To determine the equilibrium solubility and the apparent oil/water partition coefficient of silymarin in different pH phosphate buffer solutions in 37 ℃.Methods A shake flask-ultraviolet spectrophotometry method was applied to determine the equilibrium solubility and partition coefficient of silymarin.Concentrations of silymarin in n-octanol-buffer solutions of different pH were detected by UV.Results The equilibrium solubility of silymarin in different phosphate buffer solution of pH 2.0,3.0,4.0,5.0,6.0,6.8,7.4,8.0,9.0 were 0.673,0.681,0.776,0.848,0.937,1.218,1.486,1.504,1.691 mg·mL^-1,and the oil/water apparent partition coefficient of silymarin in different pH respectively were 57.12,10.83,15.56,7.39,10.19,3.82,2.75,1.79,0.84 in 37 ℃.Conclusion The equilibrium solubility and apparent oil/water partition coefficient were correlated to the pH of medium.With the increase of pH value,the equilibrium solubility rised,while the apparent oil/water partition coefficient decreased.