High-performance liquid chromatography determination of dextromethorphan and dextrorphan for oxidation phenotyping by fluorescence and ultraviolet detection

Y. W.Francis Lam, S. Y. Rodriguez

Research output: Contribution to journalArticlepeer-review

46 Scopus citations

Abstract

To establish the usefulness of fluorescence detection to quantify urinary concentrations of dextromethorphan and dextrorphan for oxidation phenotyping, we determined the molar concentration ratio of dextromethorphan to dextrorphan in 38 subjects by UV and fluorescence detection. Dextromethorphan and dextrorphan concentrations were quantified after overnight hydrolysis of urine samples and organic solvent extraction with heptane and butanol. The compounds were separated by high-performance liquid chromatography using a phenyl column and a mobile phase consisting of acetonitrile and an aqueous mixture of 0.01 M heptane sulfonic acid and 0.01 M phosphate buffer. The eluents were detected in series by a UV detector (280 nm) and fluorescence detector (excitation 280 nm and emission 310 nm). The dextromethorphan to dextrorphan molar concentration ratio by UV and fluorescence detection was highly correlated (r = 0.997) and not statistically different (p = 0.1036). However, increased sensitivity with fluorescence detection enabled detection of lower dextromethorphan and dextrorphan concentrations when compared with UV detection. Fluorescence detection was able to detect dextromethorphan as low as 0.02 μg/ml, which may be helpful in phenotyping individuals with extremely rapid metabolism of dextromethorphan. Fluorescence detection also produced chromatograms with significantly less interference and allows a more accurate quantitation of dextromethorphan and dextrorphan concentrations.

Original languageEnglish (US)
Pages (from-to)300-304
Number of pages5
JournalTherapeutic Drug Monitoring
Volume15
Issue number4
StatePublished - Aug 1993

Keywords

  • Drug metabolism
  • Fluorescence detection
  • High-performance liquid chromatography
  • Oxidation phenotyping

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)

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