Quantification of sirolimus by liquid chromatography-tandem mass spectrometry using on-line solid-phase extraction

Vogeser, Michael; Fleischer, Claudia; Meiser, Bruno; Groetzner, Jan; Spöhrer, Ute und Seidel, Dietrich (2002): Quantification of sirolimus by liquid chromatography-tandem mass spectrometry using on-line solid-phase extraction. In: Clinical Chemistry and Laboratory Medicine, Bd. 40, Nr. 1: S. 40-45

Abstract

Quantification of the new immunosuppressant sirolimus (syn. rapamycin; Rapamune((R))) in whole blood by chromatography is essential for its clinical use since no immunoassay is available although monitoring is mandatory. Here we report on a rapid and convenient liquid chromatography (LC)-tandem mass spectrometry method and describe our practical experience with its routine use. Whole blood samples were hemolyzed and deproteinized using an equal volume (150 mul) of a mixture of methanol/zinc sulfate solution containing the internal standard desmethoxy-rapamycin. After centrifugation, the clear supernatants were submitted to an on-line solid-phase extraction procedure using the polymeric Waters Oasis HLB(R) material, with elution of the extracts onto the analytical column in the back-flush mode by column switching. For analytical chromatography a RP-C18 column was used with 90/10 methanol/2 mM ammonium acetate as the mobile phase. A 1:10 split was used for the transfer to the mass spectrometer, a Micromass Quattro LC-tandem mass spectrometry system equipped with a Z-spray((R)) source and used in the positive electrospray ionization mode. The following transitions were recorded: sirolimus, 931>864 m/z, and desmethoxy-rapamycin (I.S.), 901>834 m/z. The analytical running time was 5 min, including on-line extraction. The method has a linear calibration curve (r>0.99; range 1.6-50 mug/l) and is rugged and precise with monthly CVs <7% at a sirolimus concentration of 13.1 mug/l in routine use; the instrumentation proved to be reliable and required minimal maintenance.

• Dokumententyp: Zeitschriftenartikel
• Publikationsform: Publisher's Version
• Fakultät: Medizin
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 1434-6621
• Allianz-/Nationallizenz: Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
• Sprache: Englisch