title: Inclusion of MPA and in a rapid multi-drug LC-tandem mass spectrometric method for simultaneous determination of immunosuppressants.
abstract: BACKGROUND
  [corrected] Mycophenolic Acid (MPA) is often co-prescribed as part of a multiple immunosuppressant drug regimen. In this study an established LC-MS/MS method for the measurement of immunosuppressants cyclosporine A, tacrolimus, sirolimus and everolimus was optimized to include MPA without changing the sample pre-treatment and the LC-MS/MS configuration.
  
  
  METHODS
  The sample pretreatment for EDTA-plasma was used as for whole blood. After protein precipitation of 50 mul EDTA-plasma fast on-line matrix clean-up was performed using a column switching program. The chromatographic step was optimized to separate MPA and its glucuronide metabolite (MPAG). Multiple reaction monitoring (MRM) was used for detection of MPA (337.7>207.2) and MPAG (513.6>207.2).
  
  
  RESULTS
  A total analysis time of 5 min was needed to separate MPA and MPAG. The method was linear between 0.05 and 50 mg/L for MPA. Analytical recoveries were >95%. Variation coefficients ranged between 3.1 and 4.1%. Method comparison for MPA was performed using a commercial HPLC-UV test. The Pearson correlation coefficients were >0.9. The Bland-Altman plot showed an excellent agreement between LC-MS/MS and HPLC-UV quantification.
  
  
  CONCLUSIONS
  We present a robust online SPE-LC-MS/MS platform for a simultaneous and fast daily therapeutic drug monitoring of five immunosuppressive drugs in whole blood and plasma samples.
authors.affiliation: Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Hospital Leipzig, Liebigstrasse 27, 04103 Leipzig, Germany. uta.ceglarek@medizin.uni-leipzig.de
authors.forename: Uta
authors.initials: U
authors.lastname: Ceglarek
authors.forename: Bruno
authors.initials: B
authors.lastname: Casetta
authors.forename: Jan
authors.initials: J
authors.lastname: Lembcke
authors.forename: Sven
authors.initials: S
authors.lastname: Baumann
authors.forename: Georg M
authors.initials: GM
authors.lastname: Fiedler
authors.forename: Joachim
authors.initials: J
authors.lastname: Thiery
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods; D016572:Cyclosporine / Q000097:blood; D000068338:Everolimus; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood*; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D009173:Mycophenolic Acid / Q000097:blood*; D012680:Sensitivity and Specificity; D020123:Sirolimus / Q000031:analogs & derivatives / Q000097:blood; D016559:Tacrolimus / Q000097:blood; D013997:Time Factors
chemical_list: D007166:Immunosuppressive Agents; D016572:Cyclosporine; D000068338:Everolimus; D009173:Mycophenolic Acid; D020123:Sirolimus; D016559:Tacrolimus