LC and LC-MS/MS Analysis for Characterization of Novel Degradation Products of Ivosidenib: Exploration of Degradation Pathways and In Silico Predictions

Ivosidenib (ISB) is an anticancer drug used to treat acute myeloid leukemia and cholangiocarcinoma. In order to determine and describe the degradation products (DPs) of ivosidenib, the International Conference on Harmonization (ICH) guidelines (Q1A, R2) suggest conducting stress degradation studies by subjecting the drug to acidic, alkaline, neutral hydrolysis, thermal, photolytic, and oxidative conditions. These studies are crucial for understanding the stability of the drug and ensuring its safe use. Liquid chromatography (LC) and LC-MS/MS are essential for identifying and characterizing these DPs. Ivosidenib is sensitive to degradation under acidic, alkaline, photolytic, and oxidative conditions at room temperature but is stable under neutral hydrolysis and thermal conditions. The separation of ISB and its four DPs was achieved using a Waters Acquity UPLC BEH C-18 column, with gradient elution comprising 0.1% trifluoroacetic acid (TFA) as mobile phase-A and acetonitrile as mobile phase-B. The detection was carried out at a wavelength of 215 nm with a flow rate of 0.3 mL/min and a 5 μL injection volume. The LOQ was 0.05%, and the LOD was 0.02% of the nominal concentration. Four DPs were identified, with DP-I predominant under acidic and alkaline conditions and DP-II under basic and oxidative conditions. Oxidative and photolytic conditions produced DP-III and DP-IV respectively. A novel HRMS-MS/TOF method was developed to identify and characterize these DPs, with each analyzed in an ESI-positive mode. Finally, Glide software was used to predict docking scores, while TOPKAT software was used to evaluate the in silico toxicity of ISB and its DPs. The in silico findings revealed that DP-III is the most active and is the least toxic.