Chiral Separatoion Of Drugs With Chiral Crown Ether And Cyclodextrins As Chiral Selectors In Capillary Electrophoresis

When the growing emphasis on the difference in physiologic activity, absorption, distribution, metabolism and toxicity in vivo between enantiomeric drugs, chiral separation becomes the important part in the drug discovery and development. Capillary electrophoresis (CE) has much advantage in chiral separation. Recently, sensitive chiral separation is more and more popular because it can be applied in the analyzing of low levels chiral compounds in biological and environmental samples, and even monitoring the enantiomertic purity of drugs. Even though offline or online sample treatment techniques and alternative detection systems can enhance the sensitivity of detection, on-column preconcentration techniques still are the most simple and economic one. Since 1997, about 10 papers report the on-column preconcentration in chiral CE, such as ITP, stacking, FASS, dual stacking, sweeping. But transient isotachophoresis (tITP) is not reported until now. In this paper, one of the online desalting and preconcentration techniques, tITP with UV–Vis absorption detection was successfully applied in chiral separation of gemifloxacin enantiomers in saline sample by (+)-(18-crown-6)-tetracarboxylic-acid (18C6H4). The selectivity and sensitivity was improved.Furthermore, 5 kinds of new synthesized dihydropyridine enantiomeric drugs, a kind of calcium channel antagonists, are separated byβ-CD, HP-β-CD, M-β-CD, CM-β-CD and Sulfatedβ-CD.Since 1920s, copolymers containing cyclodextrins as chiral selectors drew much attention and interest. Interesting features of copolymers are: the spacer arm between the polymer backbone and the CD which prevents sterical hindrance of the CD cavity, the positive charge on the backbone which improves the separation of enantiomers and high molecular mass which reduces the effective mobility of enantiomers. In our experiment, the new conpolymer was synthesized by radical conpolymerization of acrylamide and a monomer that is derived by AGE allows introduction ofβ-CD into the polymer. And then we used the acrylamide-β-CD copolymer as the selector to separate one of the dihydropyridine drugs successfully.