Determination of dextromethorphan and its o-demethylated metabolite from urine

Peter S. Marshall, Robert J Straka, Kjel Johnson

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21 Scopus citations


A high-performance liquid chromatography (HPLC) assay for the simultaneous quantitation of dextromethorphan and its O-demethylated metabolite dextrorphan from urine is described. A cyano analytical column was used with a mobile phase consisting of MeOH 16%, acetonitrile 3%, and triethylamine 0.06% at pH 2.8 and a flow rate of 1.0 ml/min. Betaxolol was used as the internal standard. Standard curves from 50 ng/ml to 10,000 ng/ml (dextrorphan), and from 50 ng/ml to 8,000 ng/ml (dextromethorphan) were developed. The peaks eluted at 7.8 min (dextrorphan), 12.2 min (betaxolol), and 17.8 min (dextromethorphan). The coefficients of variance ranged from 1.3 to 4.5% at 250 ng/ml and 0.9 to 2.5% at 5,000 ng/ml. This assay was used to determine dextromethorphan/dextrorphan molar ratios in healthy male volunteers for the purpose of determining phenotype status for the P450IID6 isozyme.

Original languageEnglish (US)
Pages (from-to)402-407
Number of pages6
JournalTherapeutic drug monitoring
Issue number5
StatePublished - Oct 1992

Bibliographical note

Copyright 2017 Elsevier B.V., All rights reserved.


  • Debrisoquinetype
  • Dextromethorphan
  • Metabolic ratio
  • P450IID6
  • Phenotyping


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