Electrophoretic chiral separation of pharmaceutical compounds with multiple stereogenic centers in charged cyclodextrin media

This paper reports the use of sulfated beta -cyclodextrins (S-beta -CDs) (d egree of substitution (DS) = 7-11 and 15), hepta-6-sulfato-beta -CD (HS-bet a -CD), heptakis (2,3-dimethyl-6-sulfato)-beta -CD (HDMS-beta -CD), and hep takis (2,3-diacetyl-6-sulfato)-beta -CD (HDAS-beta -CD) in conjunction with capillary zone electrophoresis (CZE) to separate enantiomers of several co mmercially available pharmaceutical compounds with multiple stereogenic cen ters. Compounds studied include eucatropine, fenoterol, nadolol, nafronyl, nylidrin, and pentapiperide. S-beta -CD with a relatively high degree of su bstitution is shown to be effective in separating several of these compound s due to the high selectivity. Resolution of four isomers was achieved for several of the test compounds under counter-electroosmotic flow (EOF) condi tions in less than ten minutes. Data illustrating the effects of CD concent ration and pH are presented. It is also shown that the migration order of i somers can be manipulated by changing either the CD concentration or buffer pH.