title: Simultaneous determination of buprenorphine, norbuprenorphine and the enantiomers of methadone and its metabolite (EDDP) in human plasma by liquid chromatography/mass spectrometry.
abstract: A previously reported enantioselective LC-MS assay for the determination of (R)- and (S)-methadone [Met] and (R)- and (S)-2-ethylidene-1,5-dimethyl-3,3-diphenyl-pyrrolidine [EDDP] (the primary metabolite of Met) has been adapted for use in the simultaneous determination of the plasma concentrations of Met, EDDP, buprenorphine (Bu) and norbuprenorphine (norBu). All of the target compounds were separated within 15 min using an alpha1-acid glycoprotein chiral stationary phase, a mobile phase composed of acetonitrile: ammonium acetate buffer [10 mM, pH 7.0] in a ratio of 18:82 (v/v), a flow rate of 0.9 ml/min at 25 degrees C. Deuterium labeled compounds were used as internal standards [d4-Bu, d3-norBu, (R,S)-d3-Met and (R,S)-d3-EDDP] and linear relationships between peak height ratios and drug concentrations were obtained for Bu and norBu in the range 0.2-12 ng/ml with correlation coefficients greater than 0.999. The relative standard deviations (%R.S.D.) for the intra- and inter-day precision of the method were <4.5% and for accuracy was <4.0%. The method was validated and used to analyze plasma samples obtained from opioid dependent methadone-maintained adults enrolled in a research study.
authors.affiliation: Bioanalytical and Drug Discovery Unit, Gerontology Research Center, National Institute on Aging, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224-6825, USA. rdrgzrss@yahoo.com
authors.forename: Maria Esther
authors.initials: ME
authors.lastname: Rodriguez-Rosas
authors.forename: Michelle R
authors.initials: MR
authors.lastname: Lofwall
authors.forename: Eric C
authors.initials: EC
authors.lastname: Strain
authors.forename: Danuta
authors.initials: D
authors.lastname: Siluk
authors.forename: Irving W
authors.initials: IW
authors.lastname: Wainer
mesh_terms: D002047:Buprenorphine / Q000031:analogs & derivatives* / Q000097:blood*; D002138:Calibration; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D008691:Methadone / Q000097:blood*; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D002047:Buprenorphine; C043585:norbuprenorphine; D008691:Methadone