Separation of the enantiomers of some racemic nonsteroidal aromatase inhibitors and barbiturates by capillary electrophoresis.

High-performance capillary electrophoresis (HPCE) and micellar electrokinetic capillary chromatography (MECC) were applied to the resolution of racemic nonsteroidal antiaromatase drugs and intermediates. Successful results were obtained in both modes using alpha-cyclodextrin (alpha-CD), beta-cyclodextrin (beta-CD), gamma-cyclodextrin (gamma-CD), or 2,6-di-O-methyl-beta-cyclodextrin (DM-beta-CD) as chiral selectors. Depending on the structure of the solute, one of the cyclodextrins was generally better suited for resolution of the racemate. The basic solutes were analyzed under HPCE conditions, whereas the nonionizable compounds such as glutethimide (Doriden) were analyzed in MECC mode. For the azole-type antiaromatase Fadrozole, both HPCE and MECC modes could be used to achieve the separation of the enantiomers. The influence of experimental factors such as pH, the presence of organic modifier, temperature, the micelle concentration, and the concentration of the chiral selector is also discussed on the basis of the results obtained with some chiral barbiturates. The possibility of analyzing the enantiomers directly in plasma samples was also demonstrated.