Objective To improve the solubility and bioavailability of oleanolic acid in water by means of forming supermolecular inclusion of oleanolic acid with methylated-β-cyclodextrin. Method The effect of different concentrations of methylated-β-cyclodextrin on oleanolic acid inclusion constants under different temperatures was evaluated by the assay of high performance liquid chroma-tography (HPLC) , and the phase solubility curves under different temperatures were drawn. Supermolecular inclusion constants and thermodynamic parameters of the inclusion process were also determined. Results Under different temperatures,phase solubility diagrams showed the characteristics of △L type. Under the temperatures of 25,35 and 45℃,the supermolecular inclusion constants were 6. 916,10. 39 and 27. 80 L·mol-1, respectively. For thermodynamic parameters determination, △H0=54. 59 kJ·mol-1; △S0 = 198. 4 J · mol-1·K-1; △G° = -4. 555,-6. 538 and -8. 522 kJ·mol-1. Conclusion The supermolecular clathrate of meth-ylated-β-cyclodextrin with oleanolic acid could be formed spontaneously in 1 : 1 molar ratio. The dissolvability of oleanolic acid has been siginificantly increased by the formation of supermolecular clathrate. The whole inclusion process is characterized by the entropy driven process.%目的 为提高齐墩果酸的水溶性和生物利用度,研究甲基化-β-环糊精包合齐墩果酸过程及其相关条件.方法 通过高效液相色谱法测定不同温度下不同浓度的甲基化-β-环糊精包合的齐墩果酸的量,绘制不同温度下的相溶解度曲线图,测定包合过程的超分子包合常数和热力学参数.结果 不同温度下齐墩果酸的相溶解度图均呈现出AL型特点.在25,35和45 ℃条件下甲基化-β-环糊精与齐墩果酸包合过程的超分子包合常数分别为6.916,10.39和27.80 L·mol-1,热力学参数ΔH0为54.59 kJ·mol-1,ΔS0为198.4 J·mol-1·K-1,ΔG0分别为-4.555,-6.538和-8.522 kJ·mol-1.结论 甲基化-β-环糊精与齐墩果酸可自发形成摩尔比为1∶1的包合物.形成的超分子包合物均有较好的增溶作用,整个包合过程体现为熵驱动过程.
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