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

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.