RESOLUTION IMPROVEMENT BY USE OF CARBOXYMETHYL-BETA-CYCLODEXTRIN AS CHIRAL ADDITIVE FOR THE ENANTIOMERIC SEPARATION OF BASIC DRUGS BY CAPILLARY ELECTROPHORESIS

Three beta-cyclodextrin derivatives-carboxymethyl-, dimethyl- and hydr oxypropyl-beta-cyclodextrin-were tested as chiral selectors for the en antioseparation of seven basic drugs in free solution capillary electr ophoresis, using buffers made of 100 mM phosphoric acid adjusted to pH 3.0 with triethanolamine in fused silica capillaries thermostatted at 15 degrees C. The best results with respect to chiral resolution were obtained with carboxymethyl-beta-cyclodextrin (CMCD): the enantiomers of all compounds examined were completely resolved with this beta-cyc lodextrin derivative. The influence of the CMCD concentration on the m igration times, the apparent electrophoretic mobility difference and t he resolution of the drug enantiomers was investigated thoroughly. Par ticularly impressive resolution values, up to 23.7, were obtained for several compounds in these capillary electrophoretic systems, using CM CD in the 5-15 mM concentration range.