Separation of verapamil and promethazine enantiomers by high performance capillary electrophoresis

Verapamil enantiomers could be baseline, separated using 2, 6-di-O-carboxyl-methyl-β-cyclodextrin as the chiral selector, but the enantiomers of promethazine could only be partially resolved using glutamate-β-cyclodextrin as the resolving agent. The effects of pH and concentrations of the chiral selectors on the separation were investigated. The addition of an organic modifier such as methanol to the background electrolyte deteriorated the enantioseparations.