Separation and characterization of the polymerized impurities in oxacillin sodium by 2D HPSEC and HPLC IT‐TOF MS

Abstract

The polymerized impurities in oxacillin sodium can induce allergic reaction, which can seriously threaten the health of patients. Gel filtration chromatography (GFC) is currently widely used for the analysis of polymerized impurities, but it has drawbacks. To effectively control the polymerized impurities in oxacillin sodium, a high-performance size exclusion chromatography (HPSEC) method and a reversedphase high performance liquid chromatography (RP-HPLC) method were established to replace the classical GFC method.Methods: By studying the chromatographic behavior of polymerized impurities and small molecular weight impurities in both methods with different chromatographic separation mechanisms, the polymerized impurities in oxacillin sodium were separated and detected effectively. Column-switching two-dimensional liquid chromatography was applied to eluted polymerized impurities from the HPSEC method for oxacillin sodium. Ion trap/time-of-flight mass spectrometry was applied to characterize the structures of polymerized impurities and unknown impurities eluted from the HPSEC/RP-HPLC method for oxacillin sodium.Results: The structures of 25 unknown impurities in oxacillin sodium were elucidated based on the high-resolution mass n data. Thirteen polymerized impurities were found and characterized. The corresponding relationship of impurities between the two methods was established and the specificity of the two methods was compared. The RP-HPLC method for analysis of the polymerized impurities not only has higher column efficiency and more specificity than the HPSEC method, but also higher sensitivity. Conclusions:The mechanisms of the formation of degradation impurities in oxacillin sodium were studied. The newly established RP-HPLC methods could effectively separate and detect polymerized impurities and unknown impurities in oxacillin sodium. The study of the impurity profile in oxacillin sodium provided a scientific basis for the improvement of official monographs in pharmacopoeias.Jiarui Gao and Fan Wang contributed equally to this article.

Study on the impurity profiles of cloxacillin and flucloxacillin based on liquid chromatography tandem ion trap/time‐of‐flight mass spectrometry

“…Reversed‐phase high‐performance liquid chromatography (RP‐HPLC) coupled with MS is the predominant technique for analyzing small‐weight impurities due to its high resolution and high sensitivity. Furthermore, RP‐HPLC‐MS can also be used to analyze polymerized impurities 20–22 …”

“…Furthermore, RP-HPLC-MS can also be used to analyze polymerized impurities. [20][21][22] For cloxacillin and flucloxacillin, various analytical techniques have been developed to estimate the quality of pharmaceuticals. [23][24][25][26] However, the impurity profile and the structures of many polymerized impurities in cloxacillin and flucloxacillin were not studied systematically and characterized using RP-HPLC-MS.…”