Development of a validated capillary electrophoresis method for enantiomeric purity testing of dexchlorpheniramine maleate

A capillary zone electrophoresis method has been developed for the detection of 0.1% of (R)-levochlorpheniramine maleate in samples of (S)-dexchlorpheniramine maleate. Using 1.5 mM carboxymethyl-beta-cyclodextrin in an acidic background electrolyte, resolution values of more than 10 were obtained. Under these conditions the R-enantiomer is migrating in front of the bulk S-enantiomer. The assay was validated for linearity (2-10 mug/ml; R-2 = 0.9992). selectivity [(RS)-pheniramine maleate and (RS)-brompheniramine maleate]. limit of detection (0.25 mug/ml), limit of quantification (0.75 mug/ml), analytical precision (intra- and inter-day variability), repeatability of the method (RSD=5.0%) and accuracy. In samples of dexchlorpheniramine maleate from two different manufacturers, concentrations of, respectively, 0.15% and 1.95% (m/m) of levochlorpheniramine maleate were detected. The method was compared to the HPLC method described in the European Pharmacopoeia III monograph. (C) 2002 Elsevier Science B.V. All rights reserved.