Abstract
Mycophenolate mofetil (MMF) is a widely used drug for the maintenance of immunosuppressive therapy in renal‐transplant recipients. MMF is rapidly metabolized in vivo to mycophenolic acid (MPA), a reversible, noncompetitive inhibitor of inosine monophosphate dehydrogenase, which represents a limiting enzyme in lymphocyte proliferation. MPA shows large interindividual pharmacokinetic variability: its monitoring is therefore of primary importance to achieve adequate immunosuppression with minimized risk of graft rejection or toxicity. We developed a CE method for the determination of total MPA (tMPA) in plasma, based on easy sample preparation; CE evaluation of tMPA was performed in 30 mmol/L sodium‐borate with 10 mmol/L SDS (pH 10.00) at 25°C using a 60 cm (54.5 to window) uncoated capillary with UV detection at 254 nm wavelength. MPA was readily detectable in plasma; the CE method was linear in the range of 0.7–120 μg/mL (r >0.992). Intra‐ and interassay imprecision was <7% except for the lowest spiked MPA concentration, which had an intra‐assay RSD% of 14.7 compared to 18.3 interassay. Data by CE were compared with results obtained by a validated HPLC method. CE assay of tMPA exhibited a very good correlation (r^2^ >0.988) with respect to HPLC; Bland–Altman difference versus average showed a mean of −0.18 μg/mL ± 1.14 SD. CE determination of tMPA is a robust, sensitive and reproducible method with the advantage over HPLC of being fast, simple and unexpensive, also enabling quick assessment of MPA for pharmacokinetic studies.