Chiral separation of racemic nicardipines by cyclodextrin mediated capillary zone electrophoresis

Abstract

A chiral separation method of racemic nicardipines used as a calcium antagonist by capillary electrophoresis using various derivatives of cyclodextrin was studied. The separation of racemic nicardipine hydrochloride was carried out with a 20 mmol/l Tris-phosphoric acid buffer (pH 2.5) by adding 0.1 % methyl hydroxyethyl cellulose and various cyclodextrin. Since the optimum separation was achieved with the addition of ο-m-β-CD, the migration times of d-form and l-form were 24.5 and 25.2 min, respectively. Good reproducibility with a relative standard deviation of 3.0% was obtained tor migration time of nicardipine as the results of 10 replicate determinations. The racemic nicardipine was completely separated under optimum conditions with a separation factor of 1.029. A linear correlation between the peak height and the concentration of nicardipines was obtained within the range of 451500 pg as an absolute quantity (r=0.9998). The optical purity of racemic nicardipine in a tablet could be determined without any complicated pretreatment. The present method is applicable for the routine analysis of nicardipine preparations.