Identification and characterization of novel metabolites of nintedanib by ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry with in silico toxicological assessment.

Rationale Nintedanib, an oral, triple angiokinase inhibitor, is used alongside docetaxel in the management of locally recurrent non-small-cell lung cancer and idiopathic pulmonary fibrosis. The present study deals with the identification and characterization ofin vitroandin vivostable and reactive (if any) metabolites of nintedanib and sheds light on some novel metabolites of the drug which have not been reported previously. Methods The study involved an oral administration of the drug to male Wistar rats, followed by collection of the biological matrices (urine, plasma and feces) at specific intervals for determination ofin vivometabolites. In addition,in vitrostudies were performed on human and rat liver microsomes in the presence of appropriate co-factors. The samples were subjected to protein precipitation and nitrogen evaporation prior to ultra-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry analysis. The toxicities of all the metabolites were assessedin silico, employing ADMET Predictor (TM). Results A total of 18 metabolites of nintedanib were identified in all the matrices, of which nine were found to be novel and unreported previously. The unreported metabolites were elucidated as oxidative, demethylated and glucuronide conjugates of nintedanib. Interestingly, acetonitrile adducts of a few metabolites (low concentration) were also observed. No reactive metabolites were observed in this study. Conclusions Characterization of hitherto unknownin vitroandin vivometabolites of nintedanib adds to the existing knowledge on the metabolism of the drug. Identification on the basis of the solvated adducts can be a useful approach for characterization of minor metabolites, which remain undetected owing to sensitivity issues.