Analysis of polymerized impurities in mezlocillin sodium and sulbenicillin sodium using two chromatographic separation mechanisms coupled to tandem mass spectrometry

Abstract

To effectively control the polymerized impurities in mezlocillin sodium and sulbenicillin sodium, a HPSEC method with TSK-gel G2000SWxl column and a RP-HPLC method with C18 analytical column were established to replace the classical gel filtration chromatography with Sephadex G-10 gel as stationary phase. By studying the chromatographic behavior of polymerized impurities in both methods with different chromatographic separation mechanisms, the polymerized impurities in mezlocillin sodium and sulbenicillin sodium were separated and detected effectively. The column switching two-dimension liquid chromatography ion trap/time-of-flight mass spectrometry was applied to characterize the structures of polymerized impurities eluted from the HPSEC method and RP-HPLC method for both drugs. The structures of the polymerized impurities in mezlocillin sodium and sulbenicillin sodium were deduced based on the MSn data. The results showed that the polymerized impurities detected by HPSEC method and RP-HPLC method were completely different. Therefore, two methods should be used meanwhile to control the polymerized impurities in mezlocillin sodium and sulbenicillin sodium.