Determination of optical impurity of pregabalin by HPLC with pre-column chiral derivatization

A new method for determining the optical impurity of Pregabalin is developed. The method is based on Pregabalin, and its isomers can be derivatized with Na-5-fluoro-2,4-dinitrophenyl-5-L-alanine amide. These derivated compounds can be separated by an ordinary chromatography column (Inertsil ODS-2.5 μm, 250 mm x 4.6 mm i.d.). Phosphoric acid buffer and acetonitrile (55:45, v/v) are used as mobile phase and 1.0 mL/min flow rate at room temperature. The detective wavelength is fixed at 340 nm. The results indicate that the limit of detection of R model optical impurity 1.1 x 10-8 g/mL (signal-to-noise = 3), accuracy, and repeatability is satisfied. Therefore, the method can be used for the quality control of Pregabalin.