Separation of the enantiomers of basic drugs by affinity capillary electrophoresis using a partial filling technique and α1-acid glycoprotein as chiral selectorglycoprotein as chiral selector

Summary Separation of the enantiomers of a variety of basic drugs by affinity capillary electrophoresis has been investigated using α₁-acid glycoprotein (α₁-AGP) as chiral selector. In order to use a high concentration of α₁-AGP without causing low detection sensitivity, the partial filling technique was employed. Enantiomer separations were performed under conditions (a running buffer at pH 5.0 or 6.0) causing the protein to migrate toward the injection end. Twenty nine basic racemates were successfully separated by optimizing the protein concentration, buffer pH and organic modifier. α₁-AGP obtained from three different suppliers was used to investigate differences among the proteins from different sources. Although most of the racemates were similarly separated with any of the three types of α₁-AGP, some racemates, e.g. acebutolol behaved differently with the three types. The reasons for the different enantioselectivities of the three types of α₁-AGP has not yet been clarified. The method was used to test the optical purity of commercial sulpiride enantiomers and it was found that the method was suitable and applicable for the purpose.