Characterization of stress degradation products of nintedanib by UPLC, UHPLC-Q-TOF/MS/MS and NMR: Evidence of a degradation product with a structure alert for mutagenicity

•Stress testing of nintedanib conducted according to ICH Q1A (R2) guideline.•Identification and characterization of nine degradation products by UPLC, UHPLC-Q-TOF/MS/MS, and NMR.•Degradation pathway and mechanism of nintedanib outlined.•Prediction of in silico toxicity of degradation products by employing ADMET PredictorTM software.•Identification of a degradation product having a free aromatic amine moiety, which is considered as structural alert for mutagenicity.