title: Determination of dextromethorphan and dextrorphan in human plasma by liquid chromatography/tandem mass spectrometry.
abstract: Rapid, sensitive and selective methods were developed for the determination of dextromethorphan and its major metabolite, dextrorphan, in human plasma using liquid chromatography/tandem mass spectrometry (LC/MS/MS). Plasma samples spiked with stable-isotope internal standards were prepared for analysis by a liquid-liquid back-extraction procedure. Dextromethorphan and dextrorphan were chromatographed on a short reversed-phase column, using separate isocratic mobile phase conditions optimized to elute each compound in approximately 1.1 min. For both analytes, calibration curves were obtained over four orders of magnitude and the limit of quantitation was 5 pg ml-1 using a 1 ml plasma sample volume. The accuracy across the entire range of spiked DEX and DOR concentrations was, in general, within 10% of the spiked value. The precision was generally better than 6% for replicate sample preparations at levels of 50 pg ml-1 or higher and typically better than 12% at levels below 50 pg ml-1. The method was applied for the evaluation of the pharmacokinetic profiles of dextromethorphan and dextrorphan in a human volunteer following peroral administration of a commercially available cough formulation.
authors.affiliation: Procter & Gamble Pharmaceuticals, Health Care Research Center, Mason, Ohio 45040, USA.
authors.forename: T H
authors.initials: TH
authors.lastname: Eichhold
authors.forename: L J
authors.initials: LJ
authors.lastname: Greenfield
authors.forename: S H
authors.initials: SH
authors.lastname: Hoke
authors.forename: K R
authors.initials: KR
authors.lastname: Wehmeyer
mesh_terms: D000328:Adult; D000996:Antitussive Agents / Q000097:blood* / Q000493:pharmacokinetics; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D003915:Dextromethorphan / Q000097:blood* / Q000493:pharmacokinetics; D003917:Dextrorphan / Q000097:blood* / Q000493:pharmacokinetics; D018691:Excitatory Amino Acid Antagonists / Q000097:blood* / Q000493:pharmacokinetics; D005615:Freezing; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D012996:Solutions
chemical_list: D000996:Antitussive Agents; D018691:Excitatory Amino Acid Antagonists; D012996:Solutions; D003917:Dextrorphan; D003915:Dextromethorphan