An accurate quantitative LC/ESI-MS/MS method for sirolimus in human whole blood

Nariyasu Mano, Mayumi Sato, Marina Nozawa, Yotaro Matsumoto, Masaru Mori, Hiroaki Yamaguchi, Junichi Goto, Miki Simada

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


Sirolimus is a widely used immunosuppressant that requires therapeutic drug monitoring (TDM). We optimized a preanalytical procedure that allows for the accurate quantiation of sirolimus in whole blood by LC/ESI-MS/MS with minimal matrix effects. Sirolimus is highly lipophilic, and solvents containing greater than 50% methanol were required to maintain sirolimus recovery. The final pretreatment procedure developed consists of a zinc sulfate protein precipitation, an extraction using octadecyl silyl-silica gel for eliminating water-soluble and hydrophilic compounds, and HybridSPE cartridge treatment to eliminate phospholipids. Using this procedure prior to LC/ESI-MS/MS led to the accurate and reproducible quantitation of sirolimus in human whole blood. The linear range of detection was 0.5-50. ng/mL, a range appropriate for TDM, and the method demonstrated good repeatability and intermediate precision within this quantitative range. In order to investigate the quantitative performance of this method, we compared it to two commercially available sirolimus immunoassays and our previously reported LC/ESI-MS/MS method. The immunoassays gave consistently greater values for the sirolimus concentration, and this may be related to antibody cross-reactivity with sirolimus metabolites and/or other matrix effects. Although our procedure is too long to support real-time TDM for outpatients, it can serve as reference method to assess the performance of other analytical methods that are currently available or may be developed in the future.

Original languageEnglish
Pages (from-to)987-992
Number of pages6
JournalJournal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences
Issue number13-14
Publication statusPublished - 2011 Apr 15


  • Immunoassay
  • Sirolimus
  • Therapeutic drug monitoring

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Clinical Biochemistry
  • Cell Biology


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