A validated SIM GC/MS method for the simultaneous determination of dextromethorphan and its metabolites dextrorphan, 3-methoxymorphinan and 3-hydroxymorphinan in biological matrices and its application to in vitro CYP2D6 and CYP3A4 inhibition study.
Dextromethorphan is used as a probe drug for assessing CYP2D6 and CYP3A4 activity in vivo and in vitro. A SIM GC/MS method without derivatization for the simultaneous determination of dextromethorphan and its metabolites, dextrorphan, 3-methoxymorphinan and 3-hydroxymorphinan, in human plasma, urine and in vitro incubation matrix was developed and validated. Calibration curves indicated good linearity with a coefficient of variation (r) better than 0.995. The lower limit of quantitation was found to be 10 ng/mL for all analytes in all matrices. Intra-day and inter-day precision for dextromethorphan and its metabolites was better than 9.02 and 9.91%, respectively and accuracy ranged between 91.76 and 106.27%. Recovery for dextromethorphan, its metabolites and internal standard levallorphan was greater than 72.68%. The method has been successfully applied for the in vitro inhibition of metabolism of dextromethorphan by CYP2D6 and CYP3A4 using known inhibitors of CYPs such as quinidine and verapamil.
Spanakis
Marios
M
Department of Pharmacognosy, School of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Vizirianakis
Ioannis S
IS
Mironidou-Tzouveleki
Maria
M
Niopas
Ioannis
I
D000996:Antitussive Agents / Q000097:blood / Q000378:metabolism / Q000652:urine; D002138:Calibration; D019389:Cytochrome P-450 CYP2D6 / Q000378:metabolism; D065690:Cytochrome P-450 CYP2D6 Inhibitors; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism; D065692:Cytochrome P-450 CYP3A Inhibitors; D003915:Dextromethorphan / Q000031:analogs & derivatives* / Q000032:analysis* / Q000097:blood / Q000378:metabolism* / Q000652:urine; D003917:Dextrorphan / Q000032:analysis* / Q000097:blood / Q000652:urine; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000996:Antitussive Agents; D065690:Cytochrome P-450 CYP2D6 Inhibitors; D065692:Cytochrome P-450 CYP3A Inhibitors; D003917:Dextrorphan; C028657:3-methoxymorphinan; D003915:Dextromethorphan; D019389:Cytochrome P-450 CYP2D6; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; C054116:norlevorphanol