SEPARATION OF STEREOISOMERS OF AMINOGLUTETHIMIDE USING 3 CAPILLARY ELECTROPHORETIC TECHNIQUES

A novel approach to capillary electrokinetic chromatography involving differential distribution between neutral and charged cyclodextrins is described for the separation of the enantiomeric pair of the drug ami noglutethimide. For comparison purposes, micellar electrokinetic capil lary chromatography and capillary electrophoresis with neutral cyclode xtrin additives are also evaluated for this separation. The three tech niques are compared in terms of their ability to resolve the two enant iomers. At pH 9, where aminoglutethimide is neutral, the enantiomers w ere resolved using a running buffer containing 5 mM carboxymethyl-beta -cyclodextrin, 1 mM beta-cyclodextrin, and 50% (v/v) methanol. At the same pH, micellar electrokinetic capillary chromatography, using a run ning buffer containing 50 mM sodium dodecyl sulfate and 17.5 mM beta-c yclodextrin, only partially resolved the enantiomers. However, at pH 3 , where aminoglutethimide is ionized, the enantiomeric pair was separa ted using capillary electrophoresis with either 10 mM alpha-cyclodextr in or 5 mM gamma-cyclodextrin added to the running buffer. Enantiomeri c separations, by way of the three electrophoretic capillary chromatog raphic techniques mentioned above, are presented and mechanisms of chi ral recognition of aminoglutethimide by cyclodextrins under various ex perimental conditions an also discussed.