Metabolism profile of quinocetone in swine by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry

With the profile of ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC/ESI-QTOF-MS), the metabolites of quinocetone (QCT) in swine were identified and investigated. On the basis of finding, the biodistribution and elimination characters of them were revealed. Through data-dependent acquisition ways, both MS and MS/MS scans of metabolites were simultaneously acquired on the same sample injection. The metabolites were reliably characterized by their accurate MS/MS spectra and their different fragmentation pathways. A total of 42 metabolites were found in swine, 11 (Q32–Q42) of them were identified to be novel in vivo. The results demonstrated that QCT was extensively metabolized and distributed in vivo, especially in gastrointestinal tract. The reductions of the N → O group, carbonyl, double-bond in QCT were the main metabolic pathways observed in swine. Elimination of the four major metabolites (Q1, Q2, Q7, Q39) of QCT suggest that QCT was mainly metabolized at 12 h in swine, then excreted gradually together with its main metabolites after that. QCT and its major metabolites are excreted more and more rapidly in swine liver, kidney and muscle, respectively. It afforded prima research of QCT metabolism in vivo of swine and given an important basis for further study of its toxicological safety evaluation and marker residue finding.