Comparison of two high-performance liquid chromatography methods for measuring blood mycophenolic acid concentrations

This study aimed to determine the accuracy of the evaluation system for LM1010 （HITACHI High-Tech Science, Tokyo, Japan） based on high-performance liquid chromatography coupled with ultraviolet-visible spectroscopy for therapeutic drug monitoring of the active metabolite mycophenolic acid （MPA） of mycophenolate mofetil （MMF） following renal transplantation and immunosuppressant therapy. We included six patients （including 4 males and 2 females; mean age, 49±13 years） who provided written informed consent. Blood sampling was performed at 0, 1, 2, 3, 4, 6, and 9hr after the administration of 750mg of MMF. The resulting measurements using the LM1010 method and the outsourcing method, high-performance liquid chromatography-mass spectrometry （HPLC-MS/MS）, were compared. The serum concentration of MPA was not significantly different between the LM1010 and HPLC-MS/MS methods for the 42 samples from six patients （4.2±3.5 vs. 4.5±4.1µg/ml）. MPA measurements were correlated with LM1010 and HPLC-MS/MS （r2＝0.9459）. No significant differences in pharmacokinetic parameters, that is, peak serum concentration （Cmax） （8.6±4.7 vs. 8.9±5.7µg/ml）, time to peak serum concentration （Tmax） （2.4±1.1 vs. 2.4±1.1hr）, estimated serum concentration 12hr after oral administration （C12） （1.3±1.6 vs. 1.4±1.8µg/ml）, and area under the serum concentration-time curve 0-12hr after oral administration （AUC0-12） （40.6±28.2 vs. 36.9±34.1µg/ml）, were observed between LM1010 and HPLC-MS/MS. In clinical settings, LM1010 can help determine the MPA concentration in patients treated with MMF after renal transplantation.