Development and validation of a capillary electrophoresis method for the enantiomeric purity determination of RS86017 using experimental design

A selective capillary electrophoresis method for determination of enantiomeric purity of RS86017, a new antiarrhythmic agent with two chiral centers, was developed and validated using sulfobutyl ether-β-cyclodextrin as chiral selector. The concentration of the chiral selector and organic modifier, pH of background electrolyte (BGE), capillary temperature, and applied voltage were systematically optimized by using orthogonal design and concentration of chiral selector was further optimized. The optimal conditions included 25 mM phosphate buffer at pH 8.0, containing 28 mg/mL sulfobutyl ether-β-cyclodextrin and 20% acetonitrile as running buffer, an applied voltage of 22 kV, and a temperature of 20 °C. The detection wavelength was 206 nm. The obtained method was capable of separating RS86017 from its potential chiral impurities, the S,R-enantiomer, the R,R-diastereomer and the S,S-diastereomer with a short analysis time of 10 min. The separation was validated with respect to its selectivity, repeatability, linearity, precision, accuracy, limits of detection (LOD), limits of quantitation (LOQ) and robustness testing. The LODs and LOQs were 0.8 μg/mL and 2.5 μg/mL for all isomers of RS86017, respectively. Finally, the method was used to investigate the chiral purity of RS86017 in bulk samples.