Use of cyclodextrins in the capillary electrophoretic separation of erythro- and threo-mefloquine enantiomers

Capillary zone electrophoresis has been used for the enantiomer separation of mefloquine diastereaisomers and enantiomers using a background electrolyte at acidic pH supplemented with ?-cyclodextrin derivatives as chiral selectors. The cyclodextrin type and concentration strongly influenced the chiral resolution and among the cyclodextrins used (?-cycle dextrin, dimethylated-, trimethylated- and carboxymethylated-?-cyclodextrin), 2,6,-di-O-methyl-?-cyclodextrin allowed to obtain very good resolution for all the studied optical isomers even at very low concentration. The optimized electrophoretic method resulted to be very reproducible for both migration time and peak areas (STD%<=1%) with a good detection limit (1·10-6 M gave a signal to noise ratio=3 for each enantiomer). The analysis of a pharmaceutical preparation did not reveal the presence of the three isomers but only the acemic erythro-mefloquine. Method recovery values, performed on a pharmaceutical preparation, were found in the range 99-102%.