Analysis of the polymerized impurities in cefmetazole sodium based on novel separation principle by liquid chromatography tandem ion trap/time-of-flight mass spectrometry

To effectively control the polymerized impurities in cefmetazole sodium, novel high performance gel filtration chromatography (HPSEC) with TSK-gel G2000SWxl column and RP-HPLC method with C₁₈ column were used in replace of classical gel filtration chromatography with Sephadex G-10 gel. By studying the chromatographic behavior of polymerized impurities in both chromatographic systems with different chromatographic separation principles, the polymerized impurities in cefmetazole sodium were separated and detected effectively. The two-dimensional liquid chromatography tandem ion trap/time-of-flight mass spectrometry (2D LC-IT-TOF MS) was applied to characterize the structures of polymerized impurities eluted from HPSEC method, and liquid chromatography tandem ion trap/time-of-flight mass spectrometry was applied to characterize the structures of polymerized impurities and other unknown impurities eluted from RP-HPLC method. The structures of fourteen unknown impurities in cefmetazole sodium were deduced based on the MS ⁿ data, nine of which were polymerized impurities. The corresponding relationship between impurities in the HPSEC method and RP-HPLC method was established, and the specificity of the two methods was evaluated. The RP-HPLC method for analysis of the polymerized impurities has higher column efficiency and specificity than the HPSEC method. The RP-HPLC method is suitable for quality control of the polymerized impurities in cefmetazole sodium. The forming mechanisms of degradation impurities in cefmetazole sodium were also studied.

Characterization of eight unknown impurities and analysis of their source in xinfujunsu and injection by liquid chromatography coupled with ion trap/time-of-flight mass spectrometry

Eight unknown impurities in xinfujunsu and its injection were characterized by liquid chromatography coupled with ion trap/time-of-flight mass spectrometry (LC-IT-TOF MS). In order to determine the m/z values of the molecular ions and predict the formulas of all detected impurities, full scan LC-MS in positive ion mode was firstly executed to obtain the m/z value of the molecules. Then LC-MS², LC-MS³ and LC-MS⁴ were carried out on target compounds to obtain as much structural information as possible. Based on MSⁿ spectral data and exact mass measurements, the chemical structures of eight unknown impurities were characterized, among which three impurities were degradation impurities and five impurities were process impurities. In addition, the source of impurities and the correlation between process and impurities were also studied. The production of degraded impurities was caused in the high pressure sterilization process of xinfujunsu injection. Based on characterization of impurities, this study revealed the cause of impurity production and provided guidance for enterprises to improve the process to reduce impurity content. Furthermore, this study also provided scientific basis for the further improvement of official monographs in pharmacopoeias.