Improvement Research of Determination for the Related Substances in Epalrestat by HPLC

OBJECTIVE To establish an improved HPLC method for the determination of the related substances in epalrestat. METHODS The chromatographic seperation was achieved on an Elite Hypersil BDS C₁₈ column(250 mm×4.6 mm, 5 μm) with the mobile phase consisted of acetonitrile-phosphate buffer salt (0.025 mol·L^-1 KH₂PO₄ + 0.025 mol·L^-1 Na₂HPO₄) at pH 6.5 adjusted with phosphoric acid, used gradient elution at the flow rate of 1.0 mL·min^-1. The detection wavelengths were set at 396 nm and 280 nm, and the injection volume was 20 μL. The column temperature was maintained at 30℃. RESULTS The stereoisomer had good linear relationship within the range of concentration of 0.010-30 μg·mL^-1, the LOD and LOQ of stereoisomer was 0.80 and 2.4 ng·mL^-1, respectively. Other validation parameters, including precision, sample stability, accuracy and robustness were all within the acceptance range. CONCLUSION The developed method is successfully applied to the determination of related substances in epalrestat.