Validated chiral high-performance liquid chromatographic method for the determination of trans-(−)-paroxetine and its enantiomer in bulk and pharmaceutical formulations

A stereospecific high-performance liquid chromatography method for the determination of trans-(−)-paroxetine and its enantiomer in bulk raw material and pharmaceutical formulations was developed and validated. The enantiomeric separation was achieved, without any derivatization, on a carbamate derivative-based column (Chiralpak AD). The effect of the organic modifiers, 2-propanol and ethanol, in the mobile phases was optimised to obtain enantiomeric separation. Limits of detection and quantitation of 2 and 6 ng, respectively, were obtained for both of the enantiomers. The linearity was established in the range of 5–41 μg for trans-(−)-paroxetine and in the range of 10–160 ng for trans-(+)-paroxetine. The accuracy of the method was 102.3% (mean value) for trans-(−)-paroxetine and 99.9% (mean value) for trans-(+)-paroxetine. For the precision (repeatability), a relative standard deviation value of 1.5% (mean value) for trans-(−)-paroxetine and of 2.1% (mean value) for trans-(+)-paroxetine was found. The method is capable of determining a minimum limit of 0.2% of trans-(+)-isomer in commercial samples.