Pharmacokinetics of enteric-coated mycophenolate sodium in stable pediatric renal transplant recipients

This study aims to characterize the pharmacokinetics of mycophenolic acid (MPA) and its glucuronide metabolite (mycophenolic acid 7-O-glucuronide, MPAG) following single oral administration of enteric-coated mycophenolate sodium (EC-MPS, myfortic) at an approximate dose level of 450 mg/m(2) body surface area (BSA) to 25 stable renal transplant recipients (aged 5-16 yr), and to evaluate the safety and tolerability of EC-MPS in this pediatric population. Patients had been maintained on a cyclosporine emulsion, Neoral-based immunosuppressive regimen for at least 3 months and had received their first or second renal transplant more than 6 months prior to entry into the study. After a brief lag phase (t(lag) 0.75 h), MPA was rapidly absorbed (t(max) 2.5 h) and rapidly converted to MPAG (t(max) 3.25 h), with relatively high plasma concentrations of MPAG (C(max) 67.7 microg/mL) compared with MPA (C(max) 36.3 microg/mL). The elimination half-life for MPAG was slightly longer than for MPA (approximately 13 h vs. 8.5 h), and the apparent oral clearance of MPA was approximately 0.2 L/h/kg. The pharmacokinetics of MPA or MPAG were not affected by age, body weight or BSA, within the study population. The pharmacokinetic results for pediatric patients are comparable with those obtained previously in adults, although exposure based on AUC(0-infinity) was approximately 23% higher, and this finding may be a result of dosing on the basis of BSA, rather than body weight. The recommended dose of EC-MPS in pediatric patients is 400-450 mg/m(2) twice daily or, alternatively, approximately 10-14 mg/kg twice daily when used in combination with cyclosporine microemulsion.