Isolation, characterisation and synthesis of a new quinidine metabolite

Eur J Drug Metab Pharmacokinet. 1982 Jan-Mar;7(1):31-8. doi: 10.1007/BF03189540.


In addition to the well-known quinidine metabolites, 2'-quinidinone and 3-hydroxy-quinidine, a third metabolic product was detected in the plasma of cardiac patients receiving quinidine therapy. Mass spectroscopic, 13C- and 1H-NMR studies, together with information on UV and IR properties of the isolated and also synthetically accessible compound, suggested the presence of an aliphatic N-oxide group. The structure of quinidine-N-oxide for the hitherto unknown metabolite was finally confirmed by X-ray diffraction analysis. Evidence was found to indicate that a contaminant in quinidine preparations, dihydroquinidine, is metabolized with respect to N-oxidation in the same way as quinidine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biotransformation
  • Body Fluids / analysis
  • Chromatography, High Pressure Liquid / methods
  • Humans
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Quinidine / metabolism*
  • Spectrophotometry, Ultraviolet
  • X-Ray Diffraction


  • Quinidine