Forced degradation study of baricitinib and structural characterization of its degradation impurities by high‐resolution mass spectrometry and nuclear magnetic resonance spectroscopy

Abstract

RationaleBaricitinib (BARI), an inhibitor of Janus kinases 1 and 2 (JAK 1/2), is used for the treatment of rheumatoid arthritis and COVID‐19. The present study focuses on establishing the forced degradation behavior of BARI under different degradation conditions (hydrolysis, oxidation, and photolysis) following International Council for Harmonization (ICH) guidelines of Q1A (R2)—Stability testing of new drug substances and products and Q1B—Photostability testing of new drug substances and products. This study helps in monitoring the quality and safety of BARI and its product development.MethodsPrior to conducting the study, the in silico degradation profile of BARI was predicted by Zeneth. Reversed‐phase high‐performance liquid chromatography employing a gradient program was used for the identification and separation of degradation impurities with an InertSustain C8 column (4.6 × 250 mm, 5 μm). The mobile phases used were 10 mM ammonium formate (pH 2.89) and acetonitrile. High‐resolution mass spectrometry (HRMS) was used for the structural elucidation of the degradation impurities.ResultsBARI was labile to hydrolytic (acidic, basic, and neutral) and photolytic degradation conditions which yielded 10 new degradation impurities and it was stable under oxidative (H2O2) conditions. The separated degradation impurities were characterized by HRMS and the respective degradation pathways were proposed. The generated information helped to propose a mechanism for the formation of the degradation impurities. Additionally, one‐dimensional and two‐dimensional nuclear magnetic resonance spectroscopy were used for the characterization of two major degradation impurities.ConclusionThe forced degradation study of BARI was carried out in accordance with ICH Q1A and Q1B guidelines, which resulted in the formation of 10 new degradation impurities. In our analysis, three degradation impurities were matching with the Zeneth predictions. In silico tools, DEREK Nexus® and SARAH Nexus®, were used for predicting the toxicity and mutagenicity of BARI and its degradation impurities. Overall, this study sheds light on BARI's safety monitoring and storage circumstances.