title: An on-line solid phase extraction procedure for the routine quantification of caspofungin by liquid chromatography-tandem mass spectrometry.
abstract: BACKGROUND
  Extensive sets of data are required to investigate the potential use of a therapeutic drug monitoring with individualization of dosage of the antimycotic compound caspofungin. The goal was to develop an improved liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for this aim.
  
  
  METHODS
  Following protein precipitation, on-line solid phase extraction was performed for sample preparation. As the internal standard compound the veterinary drug tylosin was used. A standard validation protocol was applied.
  
  
  RESULTS
  Good reproducibility and accuracy of the method were observed. On-line solid phase extraction resulted in a convenient work-flow and good robustness of the method.
  
  
  CONCLUSIONS
  This improved LC-MS/MS method was found reliable and convenient. It can be suggested for further work on the clinical pharmacology of caspofungin in the setting of clinical research laboratories.
authors: Institute of Clinical Chemistry, Hospital of the University of Munich, Munich, Germany. fabian.kirchhoff@med.uni-muenchen.de
authors: Fabian
authors: F
authors: Kirchhoff
authors: Barbara
authors: B
authors: Maier
authors: Christina
authors: C
authors: Rieger
authors: Helmut
authors: H
authors: Ostermann
authors: Ute
authors: U
authors: Spöhrer
authors: Michael
authors: M
authors: Vogeser
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods*; D000077336:Caspofungin; D002853:Chromatography, Liquid / Q000379:methods*; D054714:Echinocandins / Q000097:blood* / Q000302:isolation & purification*; D006801:Humans; D055666:Lipopeptides; D009862:Online Systems; D015203:Reproducibility of Results; D052616:Solid Phase Extraction / Q000295:instrumentation / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D054714:Echinocandins; D055666:Lipopeptides; D000077336:Caspofungin