中文摘要：

目的测定新穿心莲内酯在正辛醇-水和正辛醇-缓冲液体系中的表观油水分配系数，为体内吸收研究提供参考。方法采用高效液相色谱（HPLC）法测定新穿心莲内酯的浓度，采用摇瓶法测定新穿心莲内酯的表观油水分配系数。结果37℃下新穿心莲内酯的表观油水分配系数为1．75（10gPapp=0．24），在pH2—12的缓冲液中测得的分别为1．63、1．49、1．62、2．18、2．78、2．32、2．20、2．10、2．09、1．96、1．72、1．19。结论pH值对新穿心莲内酯的表观油水分配系数有一定影响。在一定范围内，pH值增加可使新穿心莲内酯的表观油水分配系数减小。新穿心莲内酯在pH6磷酸盐缓冲液时表观油水分配系数最大[2．78（10gPapp=0．44）]。

英文摘要：

Objective To determinate the apparent oil-water partition coefficient of neoandrographolide in n-octanolwater and n-octanol-buffer system, and to provide reference for the in vivo absorption study. Methods The concentration of neoandrographolide was determined by HPLC. The apparent oil-water partition coefficient of neoandrographolide was measured by shaking flask method. Results The apparent oil-water partition coefficient of neoandrographolide was 1.75 （ log Papp = 0.24） in water at 37℃. While the pH values of the buffer solution were from 2 to 12, the apparent oil-water partition coefficients were 1.63, 1.49, 1.62, 2. 18, 2.78, 2.32, 2.20, 2. 10, 2.09, 1.96, 1.72, and 1. 19, respectively. Conclusion The apparent oil-water partition coefficient of neoandrographolide was influenced by pH value, and the higher pH can decrease its relevant apparent oil-water partition coefficient. Neoandrographolide has the highest partition coefficient in phosphate buffer with pH 6.