Determination of enantiomeric impurity of levamlodipine besylate bulk drug by capillary electrophoresis using carboxymethyl-β-cyclodextrin

A rapid capillary electrophoresis method using carboxymethyl-β-cyclodextrin (CM-β-CD) as chiral selector was developed and validated for the enantiomeric purity determination of levamlodipine besylate bulk drug. Several parameters for were optimized for a satisfactory enantioresolution, including pH of background electrolyte, the concentration of chiral selector, buffer concentration, capillary temperature and voltage. The highest resolution (Rs = 9.8) was obtained with 4 mM CM-β-CD dissolved in 40 mM phosphate buffer (pH 3.5), at temperature 25 °C and voltage 30 kV, normal polarity. This method was fully validated for the enantiomeric purity determination of the R-amlodipine at the 0.2 % level. The established method was validated in terms of selectivity, LOD and LOQ (0.001 and 0.003 mg mL(-1)), linearity (y = 2.8943x + 0.1386, r (2) = 0.9991), precision and accuracy (95-104 %). Finally, the method was further applied to investigate the enantiomeric purity of levamlodipine in bulk samples.