基于HPLC法测定醋酸甲羟孕酮的平衡溶解度与油水分配系数

Determination of equilibrium solubility and oil/water partition coefficient of medroxyprogesterone acetate by HPLC

目的对醋酸甲羟孕酮(MPA)在不同溶剂中的平衡溶解度及其在正辛醇-缓冲液体系中的油水分配系数进行测定。方法采用HPLC法测定MPA的质量浓度,测定MPA在水、有机溶剂、缓冲溶液和加十二烷基硫酸钠的缓冲溶液中的平衡溶解度,采用摇瓶法结合HPLC法测定MPA在正辛醇-缓冲液体系中的质量浓度,从而计算油水分配系数。结果 37℃时,MPA在蒸馏水和丙酮中的平衡溶解度分别为0.52±0.04和238.70±0.47μg·mL^(-1);在体积分数为90%的乙醇溶液中的平衡溶解度最大;在加十二烷基硫酸钠的缓冲溶液中的平衡溶解度增大;在水中的表观油水分配系数为1.99(lgP=0.30),脂溶性较强;在pH值为1.2~6.8的缓冲溶液中,平衡溶解度随pH值的升高而减小,油水分配系数随pH值的升高而增大。结论该实验建立的测定方法可准确测定MPA的平衡溶解度和油水分配系数。

Objective To determine the equilibrium solubility of medroxyprogesterone acetate（MPA）in different solvents and its oil/water partition coefficient in n-octanol-buffer solution system.Methods An HPLC method was established to determine the mass concentration of MPA and the mass concentration of MPA in water,organic solvents,buffer solutions and buffer solutions with sodium dodecyl sulfate.A shake flask-HPLC method was applied to determine the mass concentration in octanol and water phase of MPA,so as to calculate the value of the oil/water partition coefficient.Results The equilibrium solubility of MPA in water and acetone was 0.52±0.04 and 238.70±0.47mg·mL-1 at 37℃respectively;equilibrium solubility of MPA in volume fraction of 90%ethanol solution was the largest;the apparent partition coefficient of MPA in the octanol-water solution system was 1.99（lgP=0.30）and high liposolubility;the equilibrium solubility and apparent partition coefficient of MPA were changed respectively when pH value increased from 1.2to 6.8in various pH buffer solutions.Conclusion This method can be used to accurately determine the equilibrium solubility and oil/water partition coefficient of MPA.