A rapid liquid chromatography-tandem mass spectrometry analysis of whole blood sirolimus using turbulent flow technology for online extraction.
BACKGROUND
Sirolimus is an immunosuppressant used in solid organ transplantation. Due to variable individual pharmacokinetics and narrow therapeutic ranges, therapeutic drug monitoring (TDM) is critical to the success of post-transplantation patient care. We developed a rapid method quantifying whole blood sirolimus using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with an automated online extraction technology.


METHODS
Whole blood (100 microL) was mixed with a precipitation solution containing internal standard (32-desmethoxyrapamycin) and centrifuged at 15,634 x g for 10 min. The supernatant (50 microL) was injected onto a turbulent flow preparatory column and then a C18 analytical column. The mass spectrometer was set for positive electrospray to monitor the ammonium adducts.


RESULTS
Analytical time was 4 min/injection. Inter- and intra-assay variation coefficients across three concentration levels ranged from 2.3% to 7.4%. The method was linear from 1.0 to 100.0 ng/mL with an accuracy of 93.3%-100.0%. No carryover was detected from samples at 313.6 ng/mL. There was no obvious ion suppression from patient samples or interference from other commonly used immunosuppressants. Good correlation with an in-house commercial LC-MS was observed.


CONCLUSIONS
The LC-MS/MS method coupled with turbulent flow technology is rapid and efficient in TDM of whole blood sirolimus.
Department of Clinical Pathology, Cleveland Clinic, Cleveland, OH 44195, USA. Wangs2@ccf.org
Sihe
S
Wang
Abby
A
Miller
D002138:Calibration; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D011090:Polyenes / Q000032:analysis / Q000592:standards; D012015:Reference Standards; D015203:Reproducibility of Results; D020123:Sirolimus / Q000032:analysis / Q000097:blood*; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry / Q000379:methods*
C113323:32-desmethoxyrapamycin; D011090:Polyenes; D020123:Sirolimus