title: Validated Method for the Quantification of Baclofen in Human Plasma Using Solid-Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry.
abstract: A highly sensitive and fully validated method was developed for the quantification of baclofen in human plasma. After adjusting the pH of the plasma samples using a phosphate buffer solution (pH 4), baclofen was purified using mixed mode (C8/cation exchange) solid-phase extraction (SPE) cartridges. Endogenous water-soluble compounds and lipids were removed from the cartridges before the samples were eluted and concentrated. The samples were analyzed using triple-quadrupole liquid chromatography-tandem mass spectrometry (LC-MS-MS) with triggered dynamic multiple reaction monitoring mode for simultaneous quantification and confirmation. The assay was linear from 25 to 1,000 ng/mL (r(2) > 0.999; n = 6). Intraday (n = 6) and interday (n = 15) imprecisions (% relative standard deviation) were <5%, and the average recovery was 30%. The limit of detection of the method was 5 ng/mL, and the limit of quantification was 25 ng/mL. Plasma samples from healthy male volunteers (n = 9, median age: 22) given two single oral doses of baclofen (10 and 60 mg) on nonconsecutive days were analyzed to demonstrate method applicability.
authors.affiliation: Toxicology Unit, Imperial College London, London W6 8RP, UK l.nahar@imperial.ac.uk.
authors.forename: Limon Khatun
authors.initials: LK
authors.lastname: Nahar
authors.affiliation: Toxicology Unit, Imperial College London, London W6 8RP, UK.
authors.forename: Rosa Elena
authors.initials: RE
authors.lastname: Cordero
authors.affiliation: Centre for Neuropsychopharmacology, Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK.
authors.forename: David
authors.initials: D
authors.lastname: Nutt
authors.affiliation: Centre for Neuropsychopharmacology, Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK.
authors.forename: Anne
authors.initials: A
authors.lastname: Lingford-Hughes
authors.affiliation: Centre for Neuropsychopharmacology, Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK.
authors.forename: Samuel
authors.initials: S
authors.lastname: Turton
authors.affiliation: Centre for Neuropsychopharmacology, Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK.
authors.forename: Claire
authors.initials: C
authors.lastname: Durant
authors.affiliation: Centre for Neuropsychopharmacology, Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK.
authors.forename: Sue
authors.initials: S
authors.lastname: Wilson
authors.affiliation: Toxicology Unit, Imperial College London, London W6 8RP, UK.
authors.forename: Sue
authors.initials: S
authors.lastname: Paterson
mesh_terms: D000328:Adult; D001418:Baclofen / Q000008:administration & dosage / Q000032:analysis* / Q000097:blood; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003903:Deuterium / Q000737:chemistry; D058786:GABA-B Receptor Agonists / Q000008:administration & dosage / Q000032:analysis* / Q000097:blood; D006801:Humans; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D008297:Male; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry / Q000379:methods*; D055815:Young Adult
chemical_list: D058786:GABA-B Receptor Agonists; D003903:Deuterium; D001418:Baclofen