title: Modified high-performance liquid chromatographic method to measure both dextromethorphan and proguanil for oxidative phenotyping.
abstract: The activities of the polymorphic enzymes cytochromes P450 2D6 and 2C19 can be assessed by administering the probe drugs, dextromethorphan and proguanil, respectively. An existing high-performance liquid chromatographic technique, which measures dextromethorphan and its metabolites, has been modified to also measure proguanil and its polymorphic metabolite, cycloguanil in urine. Proguanil and cycloguanil are assayed in separate aliquots of urine to that used for dextromethorphan/dextrorphan as pretreatment with beta-glucuronidase is required for the analysis of dextrorphan. To assay all four compounds a common extraction procedure is used and a single reversed-phase column and isocratic mobile phase with UV and fluorescence detectors connected in series are required. This technique is specific and sensitive for each analyte (limits of detection, dextrorphan/dextromethorphan/proguanil: 0.1 microgram/ml, cycloguanil: 0.2 microgram/ml). All assays are linear over the concentration ranges investigated (dextromethorphan/dextrorphan: 0.5-10 micrograms/ml, proguanil/cycloguanil: 1-20 micrograms/ml). The method described therefore uses laboratory resources very efficiently for all the assays required for hydroxylation phenotyping using proguanil and dextromethorphan.
authors.affiliation: Department of Clinical Pharmacology, Royal North Shore Hospital, St. Leonards, NSW, Australia.
authors.forename: J M
authors.initials: JM
authors.lastname: Hoskins
authors.forename: G M
authors.initials: GM
authors.lastname: Shenfield
authors.forename: A S
authors.initials: AS
authors.lastname: Gross
mesh_terms: D000962:Antimalarials / Q000008:administration & dosage / Q000378:metabolism / Q000652:urine*; D000996:Antitussive Agents / Q000008:administration & dosage / Q000378:metabolism / Q000652:urine*; D001189:Aryl Hydrocarbon Hydroxylases; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002940:Circadian Rhythm; D065731:Cytochrome P-450 CYP2C19; D019389:Cytochrome P-450 CYP2D6 / Q000032:analysis / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis / Q000378:metabolism*; D003915:Dextromethorphan / Q000008:administration & dosage / Q000378:metabolism / Q000652:urine*; D006801:Humans; D006899:Mixed Function Oxygenases / Q000032:analysis / Q000378:metabolism*; D009994:Osmolar Concentration; D010641:Phenotype; D011110:Polymorphism, Genetic; D002727:Proguanil / Q000008:administration & dosage / Q000378:metabolism / Q000652:urine*; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000962:Antimalarials; D000996:Antitussive Agents; D003915:Dextromethorphan; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19; D019389:Cytochrome P-450 CYP2D6; D002727:Proguanil