A novel stability indicating mass compatible reversed‐phase high‐performance liquid chromatography for the determination of Diroximel fumarate and its related impurities

Diroximel fumarate (DRF) is a novel oral fumarate used in the treatment of multiple sclerosis. Comprehending DRF's stability behavior in different degradation conditions is crucial and has been studied under photolysis, oxidative, hydrolysis, and thermal conditions. Nucleosil C18 column (250 × 4.6 mm, 5 μm) was employed to achieve drug separation, with a mobile phase comprising of water and acetonitrile (65:35, v/v). The flow rate was 1 mL/min and detection was performed at 210 nm using a photodiode array detector. The fully validated reversed phase‐high‐performance liquid chromatography stability method as per the International Council for Harmonization Q2 R1 demonstrated excellent selectivity, accuracy, and precision with good sensitivity. During the analysis, two prominent degradant product peaks of DRF were identified across all stress conditions. The usage of liquid chromatography‐mass spectrometry compatible solvents in the mobile phase permits further characterization of DRF and its degradants peak. Significant levels of degradation were found in alkaline and acidic hydroxide, peroxide, photolytic, and thermal conditions with hydrolysis being postulated as a possible mechanism of degradation. The fully validated stability‐indicating analytical method can be used for routine quality control and stability testing of DRF, requiring storage in a protected primary container, as it is sensitive to light and moisture.