Development and validation of an ultrafast chromatographic method for quantification of the immunosuppressant mycophenolic acid in canine, feline and human plasma

Mycophenolic acid (MPA) is the active metabolite of the prodrug mycophenolate mofetil. In this study, we developed and validated a novel ultra-high performance liquid chromatography (UHPLC) method for the rapid quantification of MPA in plasma from dogs, cats and humans. Following the protein precipitation, calibration standards and quality controls were separated by UHPLC reversed-phase on a 1.5 μm 2.1 × 100 mm C18 column and quantified using UV detection at 215 nm. The procedure produced a linear curve (r2 > 0.997) over the concentration range 0.4-50 μg/mL and exhibited a high degree of repeatability (CV% <11%). The limit of detection (LOD) and lower limit of quantitation (LLOQ) were 0.1 and ≤0.4 μg/mL, respectively and the overall recovery was ≥87%. By combining isocratic conditions with a UHPLC column containing solid core particles, we were able to elute MPA and the internal standard (mycophenolic acid carboxybutoxy ether) within 3.0 min. The short total run time makes this method ideal to study the disposition of MPA in large batches of plasma samples and/or monitor plasma drug concentrations, as recommended for patients that require optimized immunosuppression.