title: Isolation, characterisation and synthesis of a new quinidine metabolite.
abstract: 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.
mesh_terms: D001711:Biotransformation; D001826:Body Fluids / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D011802:Quinidine / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D014961:X-Ray Diffraction
chemical_list: D011802:Quinidine