CHIRAL SEPARATION OF BASIC DRUGS BY CAPILLARY ZONE ELECTROPHORESIS WITH CYCLODEXTRIN ADDITIVES

The enantiomers of a series of basic drugs were separated in capillary zone electrophoresis (CZE) in phosphate buffers, pH 3, containing bet a-cyclodextrin or one of its derivatives as chiral selectors and uncoa ted fused silica capillaries thermostated at 15 degrees C. The nature of the cationic component of the background electrolyte was found to h ave a significant influence on achiral resolution and peak symmetry. T he best results were obtained with triethanolamine, which was then use d to adjust the buffer pH in all further experiments. The effects on c hiral resolution of the nature and concentration of cyclodextrin, of t he addition of methanol, and of capillary temperature were studied. Ma ximum resolution was obtained at a particular cyclodextrin concentrati on for each analyte, depending on the affinity of the analyte for this cyclodextrin. On the basis of the results, the effects of methanol ad dition and temperature on enantiomeric resolution could be explained a nd predicted. Numerous chiral separations are presented and suggestion s for the rapid optimization of CZE enantioseparations with cyclodextr in additives are given.