Glycogen: A novel branched polysaccharide chiral selector in CE

Abstract

Various chiral selectors have been employed in CE and among them linear polysaccharides exhibited powerful enantioselective properties. Different from linear polysaccharides, the use of branched polysaccharides as chiral selectors in CE has not been reported previously. In this study glycogen belonging to the class of branched polysaccharides was used as a novel chiral selector for the enantiomeric separations for the first time. Since glycogen is electrically neutral, the method is applicable to ionic compounds. Eighteen chiral compounds including 12 basic drugs and six acidic drugs have been tested to demonstrate the potential of this chiral selector. BGE and selector concentrations and buffer pH were systematically optimized in order to obtain successful chiral separations. Among the tested compounds, the enantiomers of ibuprofen, which is an acidic drug, were successfully recognized by 3.0% w/v glycogen with 90 mM Tris-H(3)PO(4) buffer (pH 7.0). The enantiomers of basic drugs such as citalopram, cetirizine and nefopam were also baseline-resolved with 50 mM Tris-H(3)PO(4) buffer (pH 3.0) containing 3.0% glycogen. Amlodipine belonging to basic compound only gave partial enantioseparation under the above-mentioned condition.