Separation of Oxidative Degradation Products of the Anti-Cancer Drug Gilteritinib Fumarate by Liquid Chromatography with Photodiode Array and Mass Spectrometric Detection

Gilteritinib (GTB) is used for the treatment of refractory or relapsed acute myeloid leukemia and inhibits several receptor tyrosine kinases, including FMS-like tyrosine kinase 3 and AXL. The main objective of the current study was to determine how GTB degrades under forced conditions (hydrolysis, oxidation, and photolysis) in accordance with ICH Q1A and Q1B criteria. Zeneth software was used to predict the in-silico deterioration profile of GTB before the study was carried out. GTB was found to be stable under hydrolytic (acidic, basic, and neutral) and photolytic degradation conditions, but it was labile under oxidative (H₂O₂) conditions, producing three novel degradation products. The degradation products were identified and separated using a Phenomenex Gemini C18 column (250 × 4.6 mm, 5 µm) in a reversed-phase high-performance liquid chromatography with a gradient program. Mobile phases consisted of 10 mM ammonium formate with 0.01% acetic acid (pH unadjusted, %A) and methanol (%B). High-resolution mass spectrometry was used for the structural elucidation of the degradation products. The resulting data enabled the proposal of a mechanism for the formation of the degradation products. Using in silico techniques (DEREK Nexus, SARAH Nexus, and ProTox-3.0), the toxicity and mutagenicity of GTB and its degradation products were predicted. In summary, this study highlights safety monitoring and storage conditions for GTB.