Pharmacokinetics of mycophenolic acid and its glucuronide after a single and multiple oral dose of mycophenolate mofetil in Chinese renal transplantation recipients

Purposes. To compare the pharmacokinetic parameters of mycophenolic acid (MPA) and mycophenolic acid glucuronide (MPAG) after single and multiple oral administration of mycophenolate mofetil (MMF) in Chinese renal transplant patients with those of recipients in other countries. Methods. Twelve Chinese renal transplant patients after an overnight fast received a single 1-g dose of MMF before renal transplantation. Thereafter the patients received 1 g MMF twice a day up to and on the day 12 after renal transplantation. The concentrations of MPA and MPAG were simultaneously measured by RP-HPLC. The concentration-time data were examined with Drug and Statistics pharmacokinetic software. Using paired samples t test (self-contrast) with SPSS statistical software (alpha = 0.05), we compared the pharmacokinetic parameters between single and multiple doses. Results and discussions. The MPA concentration-time profiles were fitted to a two-compartment open model; MPAG concentration-time profiles were fitted to a single-compartment open model. Compared with the literature reports, the main pharmacokinetic parameters of MPA and MPAG shown by our research revealed some differences. The parent drug MMF was undetectable in plasma during oral administration. A secondary peak of MPA occurred at 6 to 10 hours, which was attributed to enterohepatic recirculation. There was significant variation in MPA and MPAG plasma concentration-time data among subjects. It is suggested that therapeutic drug monitoring should be applied for dosage optimization.