Determination of Mycophenolic Acid and Mycophenolic Acid Glucuronide Using Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS)

Abstract

Mycophenolic acid (MPA) is an immunosuppressant that is used in renal, liver, and heart transplantation. Due to its narrow therapeutic range, monitoring of MPA levels is essential to avoid toxicity and organ rejection. Although immunoassays are available for the determination of MPA, due to their higher specificity, mass spectrometry methods are preferred. In this unit, we describe a liquid chromatography tandem mass spectrometry (LC/MS/MS) method utilizing positive ionization electrospray and multiple reaction monitoring (MRM) for the quantification of levels of MPA and its conjugate MPA glucuronide (MPAG). Blood collected in a plain, EDTA, or heparin-containing tube is centrifuged to separate the serum or plasma. Proteins are precipitated using a solution containing zinc sulfate and acetonitrile that has been spiked with deuterated internal standards. The resulting protein-free supernatant is injected into the LC/MS/MS system for analysis. The chromatography involves the use of a C18 column and ammonium acetate/water/formic acid and ammonium acetate/methanol/formic acid mobile phases. Quantification of MPA and MPAG levels is achieved by comparing the MRM peak area ratios of analytes and internal standards, consisting of specific precursor/product pairs, with those of calibrators at various concentrations. Calibration curves are constructed from the MRM peak area ratios of calibrators and internal standards versus concentration. © 2018 by John Wiley & Sons, Inc.

Therapeutic Drug Monitoring of Micophenolate Mofetil in Cardiac Transplant Patients by Limited Sampling Strategy: An Update

“…Those with a large number of sample loads and those with research interests are likely to use the chromatographic technique. HPLC with MS detection is often described as the gold standard technique [49,50]. One of the problems that can create a bias and alter the calculation of the nomograms are the analytical methods used.…”

Quantitation of mycophenolic acid and metabolites by UPLC-MS/MS in renal transplant patients

“…It has therefore been suggested that monitoring plasma concentrations of MPA is useful to overcome the variable, especially in patients after kidney transplantation [ 4 , 5 ]. Assays for monitoring MPA include immunoassays [ 6 , 7 ], high-performance liquid chromatography with ultraviolet detection (HPLC-UV) [ 8 ], and LC-MS/MS [ 9 – 13 ]. The immunoassays approved by the FDA in 2001 are fast and easy to carry out but can over-estimate MPA concentrations due to nonspecific cross-reactions between antibodies andMPAG or AcMPAG [ 8 , 12 ].…”