Abstract: Objective To establish an analytical method for polymers in cefmetazole sodium raw materials and preparations, which can provide guidance for production quality control and effective supervision. Methods The reversed phase liquid chromatography system containing volatile buffer salt was used to separate the polymers in cefmetazole with gradient elution, and the polymers were quickly identified coupled with mass spectrometry. The location of the polymers under the chromatographic method of related substances in the Chinese Pharmacopoeia was obtained by two-dimensional liquid chromatography, and the specificity of the high performance gel chromatography and reverse-phase high performance liquid chromatography for the separation of polymers in cefmetazole was explored. Results There is one dimer present in the raw materials and preparations of cefmetazole, while the reference listed drugs and high concentration degradation samples do not contain polymers. The pharmacopoeial method can simultaneously control related substances and the polymer. Reversed-phase high performance liquid chromatography is superior to high performance gel chromatography in the specificity of separating polymers. Conclusion The adopted technical pathway can provide guidance for the research on polymers in other cephalosporin with low content and difficult identification.

Key words: Cefmezole Sodium, Polymers, High Performance Gel Chromatography, Reverse-Phase High Performance Liquid Chromatography, Two-Dimensional Liquid Chromatography, Liquid Chromatography Couple with Mass Spectrometry