雷公藤甲素及其氨基葡萄糖结合物的表观溶解度、表观油水分配系数和解离常数的测定

目的 测定雷公藤甲素及其氨基糖结合物的表观溶解度、表观油水分配系数和解离常数(pKTa).方法 采用平衡溶解度法、摇瓶法测定雷公藤甲素及其氨基糖结合物的表观溶解度和油水分配系数;采用分光光度指示剂法测定雷公藤甲素-氨基糖结合物的解离常数.结果 雷公藤甲素的表观溶解度随pH的增加而增加,其表观油水分配系数随pH的增加而降低,但变化并不显著.雷公藤甲素-氨基葡萄糖结合物的表观油水分布系数随pH的增加而增加,在纯水中的表观溶解度为1.9325±0.1373 g,pKT =5.938 ±0.191.结论 雷公藤甲素是一个难溶性的亲脂性化合物,而雷公藤甲素-氨基葡萄糖结合物是一个弱碱性的亲水性化合物.

Determination of apparent solubility,apparent oil/water partition coefficient and dissociation constant of triptolide and triptolide-glucosamine conjugate

OBJECTIVE To determine the apparent solubility,oil/water partition coefficient (P)and dissociation constant (pKTa) of triptolide and triptolide-glucosamine conjugate.METHODS The miniaturized shake-flask solubility method was adopted to determine the equilibrium solubility of triptolide andtriptolide-glucosamine conjugate.And a shake flask method was established to determine the P of triptolide and triptolide-glucosamine conjugate.The pKTa of triptolide-glucosamine conjugate was measured according to Spectrophotometric indicator method.RESULTS With pH increased,the apparent solubility of triptolide also increased while its P showed a decreasing trend.As for triptolide-glucosamine conjugate,the P increased with the increasing pH.In addition,its apparent solubilityin water was 1.9325 ± 0.1373 g and its pKTa was 5.938 ± 0.191 in water.CONCLUSION Triptolide is a slightly soluble compound with lipophicity,while triptolide-glucosamine conjugate is a weak basic compound with high hydrophicity.