Spectro-electrochemical and DFT study of tenoxicam metabolites formed by electrochemical oxidation

•Tenoxicam deprotonation and electrochemical oxidation were studied.•Both spectro-electrochemical and theoretical DFT studies were considered.•It was found that the ampholitic species of tenoxicam is a zwitterion.•Electrochemical oxidation of tenoxicam yields two non-electroactive products.•The nature of these fragments was further confirmed by a chromatography study. From experimental (spectro-electrochemical) and theoretical (DFT) studies, the mechanisms of tenoxicam deprotonation and electrochemical oxidation were assessed. From these studies, new insights on the nature of the ampholitic species involved during tenoxicam's deprotonation in aqueous solution are presented; see scheme A. Moreover, it is shown that, after the analysis of two different reaction schemes that involve up to 10 different molecules and 12 reaction paths, the electrochemical oxidation of tenoxicam, yields two non-electroactive products that are predominately formed by its fragmentation, after the loss of two electrons. The nature of these fragments was further confirmed by a chromatography study.