Related substances of domestic etamsylate

Objective To establish an HPLC method to determine the related substances of etamsylate, and to determine the structure of unknown impurity. Methods The Agilent ZORBAX NH2(4.6 mm×250 mm, 5 μm) column was used, and the mobile phase was consisted of methanol-0.2% potassium dihydrogen phosphate solution(10 :90). The fl ow rate was 1.0 mL · min- 1 with UV detective wavelength at 220 nm. Preparative liquid chromatograph was usedto obtain pure unknown impurity, and fi gure out its structure through LC/MS and NMR. Results Etamsylate and impurities were well separated under selected liquid chromatographic system. The methodological study conformed to the requirements for analysis. According to MS and NMR spectral data, the structure of unknown impurities was identified. Conclusion The method is simple, sensitive, specific, which can be used to determine simultaneously known and unknown impurities in etamsylate. The structure identification of unknown impurities provides a theoretical basis for the quality control of etamsylate.