Enantiomeric separations of drugs using mixtures of charged and neutral cyclodextrins

An overview on the use of mixtures of neutral and charged cyclodextrins as chiral additives for the enantioseparation of drugs by capillary electrophoresis is presented. These so called dual cyclodextrin systems can often provide unique selectivities. A brief theoretical background illustrating the influence of the chiral discrimination ability and the effective mobility of the two cyclodextrins on the overall selectivity of the enantiomeric separation is given. Typical examples of applications in the pharmaceutical field, based on the simultaneous use of a charged (cationic or anionic) and neutral cyclodextrins, are described.