LC-MS/TOF and MSnstudies on forced degradation behavior of flucloxacillin and development of a validated stability indicating LC method

Abstract

Summary The objective of the present investigation was to develop and validate a stability indicating liquid chromatography (LC) method which should possess potential to separate flucloxacillin as well as all the degradation products. Simultaneously, our aim was also to identify, separate, and characterize the major degradation product (DPs) of flucloxacillin, generated under various stress conditions. To achieve this objective, flucloxacillin was subjected to hydrolytic, oxidative, photolytic, and thermal stress as per International Conference on Harmonization (ICH) guidelines Q1A(R2). The drug was found to degrade in acidic, alkaline, neutral, and oxidative stress conditions and showed stable behavior in photolytic and thermal stress conditions. In total, seven degradation products were formed, which were separated on a C-18 column employing a gradient high-performance liquid chromatographic (HPLC) method. A complete mass fragmentation pathway of the drug was established with the help of multi-stage (MSn) and mass spectrometry/time of flight (MS/TOF) accurate mass studies. Then the stress samples were subjected to LC-MS/TOF studies, which provided the fragmentation pattern along with the accurate masses for a major degradation product. The entire mass spectral studies helped to identify the degradation product so as to propose its best possible structure. Finally the total information was used to establish the degradation pathway of the drug.