目的:测定田蓟苷在不同缓冲溶液和表面活性剂溶液中的平衡溶解度及在正辛醇-水/磷酸缓冲盐中表观油水分配系数(Papp),为今后新剂型的选择和制备提供参考。方法:通过高效液相色谱法测定田蓟苷在不同溶剂和表面活性剂溶液中的浓度,采用摇瓶法测定田蓟苷在正辛醇-水/磷酸缓冲盐中油水分配系数。结果:田蓟苷在37℃纯水中的平衡溶解度为1.57mg·L^-1,在甲醇、乙酸乙酯及三氯甲烷有机溶液中溶解性较好;在酸性缓冲溶液中的平衡溶解度较水中有明显增加,在碱性缓冲液中随pH的增高平衡溶解度逐渐减小。在32 g·L^-1的十二烷基硫酸钠溶液中平衡溶解度提高到188.65 mg·L^-1。田蓟苷的油水分配系数为14.63(lg P=1.17),且随溶液pH的增高逐渐增加。结论:田蓟苷为疏水性药物,脂溶性较强。制剂时,可加入适当浓度的十二烷基硫酸钠助溶。同时,提高其制剂的溶出度可能会提高其生物利用度。
OBJECTIVE To determine equilibrium solubility of tilianin in different buffer solutions and surfactant solutions,and apparent oil/water partition coefficient in n-octanol-water/buffer solution system,provide a reference for selection and preparation of novel formulations in future.METHODS Concentrations of tilianin in various media and surfactant solutions were detected by HPLC.Flask shaking method was used to determine the apparent oil-water partition coefficient of tilianin in octanolwater/buffer liquid.RESULTS Tilianin had an equilibrium solubility of 1.57 mg·L^-1 in purified water at 37 ℃,and good solubility in 70% ethanol,acetic ether and chloroform.The equilibrium solubility obviously increased in acid buffer solution than in water,and gradually reduced in alkaline buffer solutions as pH value increased.The equilibrium solubility increased to 188.65mg·L^-1 in 32 g·L^-1 sodium dodecyl sulfate solution.The apparent oil/water partition coefficient of tilianin was 14.63(lg Papp=1.17)and increased gradually as pH increased.CONCLUSION Tilianin is a hydrophobic drug with a relatively higher lipid solubility.During formulation,lauryl sodium sulfate at appropriate concentrations can be added to assist dissolution.Meanwhile,its dissolution can be increased to improve its bioavailability.