Identification of Related Substances of Moxifloxacin by Spectra Correlation in Chromatography

OBJECTIVE To develop a qualitative analysis method to identify related substances of moxifloxacin by the correlation of spectra in chromatography.METHODS The UV spectra of four related substances in moxifloxacin were measured by high-performance liquid chromatography with diode array detection(HPLC-DAD).The standard spectra of the related substances and their spectral correlative chromatography were developed and used in identification by calculating correlation coefficients.RESULTS The threshold of correlation coefficients was 0.995 and the limit amount for identification was 20 ng. CONCLUSION The method is accurate and reproducible as a new and effective way to identify impurities in drugs when relative retention times are incapable due to the changes of chromatographic system such as column or mobile phase.