毛细管电泳环糊精添加剂拆分特布他林对映体的立体选择性研究

分别测定了毛细管区带电泳环糊精手性拆分体系中α，β－环糊精和二甲基、三甲基、羟丙基－β－环糊精与药物对映体特布他林形成包结络合物的稳定常数以及手性拆分过程的热力学函数的变化。数据分析表明，环糊精稳定常数的大小反映了环糊精空腔与分离对象之间的匹配程度。环糊精稳定常数的相对值反映了手性拆分体系的分离能力。两对映体与环糊精所形成包结络合物的Δ（ΔＨ）和Δ（ΔＳ）分别反映了手性拆分过程中立体作用与构象匹配的差异。与甲基化β－环糊精相比，羟丙基－β－环糊精和β－环糊精提供的氢键作用在手性拆分中起着重要作用。

A Study on the Binding of Cyclodextrins with Terbutaline Enantiomers by Chiral Capilary Zone Electrophoresis

The recognition mechanism of enantioselectivity in cyclodextrin-modified capillary zone electrophoresis (CD-CZE) on a racemic basic drug terbutaline was discussed. The equilibrium constants of host-guest complexation of terbutaline enantiomers with alpha-cyclodextrin, beta-cyclodextrin, 2,6-dimethyl-beta-cycoldextrin, 2,3,6-trimethyl-beta-cyclodextrin and 2-hydroxy-propyl-beta-cyclodextrin, and the thermodynamic parameters for chiral recognition procedure were determined respectively. It was found that the matching properties between cavity of cyclodextrins and enantiomers were interrelated with the equilibrium constants of binding complexes and selectivities(a) calculated from the ratio of binding constants of two enantiomers were in the same order of maximum electrophoretic mobility difference between two enantiomers responding with cyclodextrin additive. The experimental value of optimal concentration of cyclodextrin agreed with that calculated from the equation Copt = 1/(K1K2)1/2. From the thermodynamic parameter determination it was shown that the hydrogen-bonding interactions between terbutaline enantiomers and 2-hydroxy-propyl-beta-cyclodextrin and beta-cyclodextrin should be positive factors.