中文摘要：

研究了七元瓜环（Q[7]）与抗癌药物阿糖胞苷（Ara-C）的不同质子化存在形式之间的超分子相互作用，探讨了超分子包合作用对药物电离平衡常数及药物稳定性的影响.结果表明， Q[7]使得 Ara-C 的 pKa降低了约0.3个单位， Q[7]与 Ara-C 的2种存在形式（Ara-C＋及 Ara-C）均可形成1：1的主客体包结配合物， Ara-C 以其嘧啶环进入 Q[7]空腔，而核糖环位于瓜环端口发生相互作用； Q[7]与 Ara-C 作用后对药物起到保护性载体的作用，从而提高了药物的稳定性.

英文摘要：

The interaction of cucurbit[7]uril（Q[7]） with cytarabine（Ara-C） in different proton forms were studied by ultraviolet absorption spectroscopy and 1 H NMR technique in details. Complexation by Q[7] has also been investigated to cause pKa shifts and stability of drug. The results showed that Q[7] encapsulated the Ara-C and shifted its pKa value by down to 0. 3 units. Ara-C in different proton forms with Q[7] informed 1 ： 1 inclusion complexes, and the formation constants were （9. 48±0. 29）×103 L/ mol and （6. 30±0. 04）×103 L/ mol for the Q[7]-Ara-C＋ system and Q[7]-Ara-C system, respectively. Moreover, The formation of inclu-sion complexes between Q[7] with Ara-C was confirmed by 1 H NMR, the pyrimidine moiety of Ara-C were entrapped in the cavity of the host and the D-ribose ring was likely located at the outside cucurbituril cavity. In addition, stability studies were investigated by initial uniform rate experiment. The results revealed that complexation of Ara-C with Q[7] offers a major improvement in drug stability.