DEXTRAN AND DEXTRIN AS CHIRAL SELECTORS IN CAPILLARY ZONE ELECTROPHORESIS

Polysaccharides such as dextrins, which are mixtures of linear alpha-( 1,4)-linked D-glucose polymers, and dextrans, which are polymers of D- glucose units linked predominantly by alpha-(1,6) bonds, have been emp loyed as chiral selectors in the capillary electrophoretic (CE) separa tion of enantiomers. Because these polymers are electrically neutral, the method is applicable to ionic compounds. Among the compounds teste d the enantiomers of ibuprofen, naproxen, warfarin and the diltiazem s ynthetic intermediate 1,1'-binaphthyl-2,2'diyl hydrogen phosphate, whi ch are anionic compounds, were successfully recognized by employing de xtran or dextrin under neutral conditions. The enantiomers of basic or cationic drugs such as timepidium, primaquine, sulconazole, trimetoqu inol, diltiazem and clentiazem were also successfully separated under acidic conditions. The effects of molecular mass and polysaccharide co ncentration on enantioselectivity were investigated. High concentratio ns of these polymers, especially dextrin, led to delayed migration tim es after repeated injections of the solutes into an uncoated capillary under neutral conditions. Consequently the capillary washing process was found to be very important to obtaining reproducible migration tim es in the system. A coated capillary was also investigated to overcome this problem. Finally, the method using electrically neutral polysacc harides was applied to the testing of the optical purity of the drug s ubstances.