A simple HPLC method for monitoring mycophenolic acid and its glucuronidated metabolite in transplant recipients.

摘要

Mycophenolic acid (MPA) is nowadays in broad clinical use as a substitute for azathioprine. An immunoassay for MPA recently received approval for clinical applications. The high performance liquid chromatography (HPLC) assay for measuring MPA and its glucuronide conjugate (MPAG) we describe here is not only rapid and simple but also extremely sensitive at plasma levels obtained during standard immunosuppressive regimens. The determination of MPAG is possible without any change of the chromatographic conditions (detection wavelength of 214 nm, mobile phase: acetonitrile and 50 mmol/l o-phosphoric acid (50:50, V/V), run time: 15 min). The required equipment is a standard HPLC system including a simple UV-detector. Sample volume of 400 microl is required for both determinations. Detection limit is 0.25 micromol/l for MPA and 5 micromol/l for MPAG. Linearity is excellent for serial dilutions (0.5-25 micromol/l for MPA, 25-500 micromol/l for MPAG) and high accuracies favour the method described. More than 2000 plasma samples tested for MPA in patients after heart transplantation within one year and more than 500 samples for MPAG underline the clinical applicability of this assay.