CAPILLARY ZONE ELECTROPHORESIS FOR SEPARATION OF DRUG ENANTIOMERS USING CYCLODEXTRINS AS CHIRAL SELECTORS - INFLUENCE OF EXPERIMENTAL PARAMETERS ON SEPARATION

Enantiomeric separations in cyclodextrin-modified capillary zone elect rophoresis (CZE) can be tuned by many experimental conditions, such as the cyclodextrin type, concentration and degree of substitution, pH a nd separation voltage. The enantiomers of rac-terbutaline, rac-terbuta line mononsulphate, rac-bambuterol, rac-propranolol, rac-ephedrine and rac-brompheniramine were used as model substances to study the effect of the above factors on separation parameters using an uncoated fused -silica capillary. The cyclodextrins used in the experiments were alph a-cyclodextin, beta-cyclodextrin, dimethyl-beta-cyclodextrin and hydro xypropyl-beta-cyclodextrin. The results were compared with those predi cted by theoretically derived models. The most effective parameters fo r optimizing resolution were pH and cyclodextrin type and concentratio n. The applied voltage was the most effective in tuning the separation time. The quality of the cyclodextrins used for the separation is of importance as both the degree of substitution of modified cyclodextrin s and the position of substitution were found to affect the separation s.