title: Determination of 8-methoxypsoralen in human plasma, and microdialysates using liquid chromatography-tandem mass spectrometry.
abstract: The validation of a LC/MS/MS method for the determination of 8-methoxypsoralen (8-MOP) in human plasma and microdialysates after topical application is described. Plasma samples were extracted by liquid-liquid extraction with diisopropylether using 4,5',8-trimethylpsoralen (TMP) as internal standard. Chromatographic separation of plasma sample extracts was carried out using a short narrow-bore Nucleosil C18 column (30 mm x 2.0 mm i.d.) with acetonitrile/(2 mM ammonium acetate buffer, 2 mM acetic acid) (80:20, v/v). For mass spectrometric analysis an API 3000 triple quadrupole mass spectrometer was employed. The mass transitions used were m/z 217.2-->174.0 for 8-MOP and m/z 229.1-->142.1 for TMP. Microdialysis samples diluted with an equal amount of acetonitrile did not require any extraction and were analyzed directly on a narrow-bore Nucleosil C18 column (70 mm x 2.0mm i.d.) with acetonitrile/(2 mM ammonium acetate buffer, 2 mM acetic acid) (50:50, v/v) with the mass transition m/z 217.2-->174.0. The assays were validated over the concentration ranges of 0.5-50 ng/ml for plasma samples and 0.25-50 ng/ml for microdialysates, respectively.
authors.affiliation: pharmazentrum frankfurt, Institut für Klinische Pharmakologie, Klinikum der Johann Wolfgang Goethe-Universität Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Bräutigam
authors.forename: Maic
authors.initials: M
authors.lastname: Seegel
authors.forename: Irmgard
authors.initials: I
authors.lastname: Tegeder
authors.forename: Helmut
authors.initials: H
authors.lastname: Schmidt
authors.forename: Silke
authors.initials: S
authors.lastname: Meier
authors.forename: Maurizio
authors.initials: M
authors.lastname: Podda
authors.forename: Roland
authors.initials: R
authors.lastname: Kaufmann
authors.forename: Marcella
authors.initials: M
authors.lastname: Grundmann-Kollmann
authors.forename: Gerd
authors.initials: G
authors.lastname: Geisslinger
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D008730:Methoxsalen / Q000097:blood*; D017551:Microdialysis; D012015:Reference Standards
chemical_list: D008730:Methoxsalen