title: The kinetics of mycophenolic acid and its glucuronide metabolite in adult kidney transplant recipients.
abstract: BACKGROUND
  Mycophenolic acid kinetics have been reported to vary after renal transplantation, and mycophenolic acid area under the concentration-time curve (AUC) is the best predictor of suppression of graft rejection.
  
  
  METHODS
  To determine whether mycophenolic acid kinetics vary after renal transplantation and to examine the potential role of enterohepatic recirculation, we investigated the kinetics of mycophenolic acid and mycophenolic acid glucuronide on days 2, 5, and 28 after transplantation in 10 kidney transplant recipients (male/female ratio, 1.5; mean age, 41.7 +/- 5.0 years) given 1 g mycophenolate mofetil twice a day. To facilitate therapeutic drug monitoring, we examined a limited sampling strategy for estimating 12-hour mycophenolic acid [AUC(0-12)].
  
  
  RESULTS
  The mean +/- SE AUC(0-12) for mycophenolic acid on day 28 was 38.5 +/- 1.6 mg x h/L, with a secondary peak 4 to 8 hours after dosing that was attributable to enterohepatic recirculation. Marked variability was shown in the kinetic profile of mycophenolic acid among patients across the three sampling days. Mycophenolic acid AUC(0-12) was positively predicted by both serum creatinine (P = .01) and serum albumin (P = .03) but not by time after transplantation, body weight, or trough concentration. Limited sampling (at 0, 1, 3, and 6 hours) accounted for 84.1% of the variability in the mycophenolic acid AUC(0-12) data and predicted the AUC(0-12) closely (r2 = 0.954) when evaluated in 10 different kidney transplant recipients.
  
  
  CONCLUSIONS
  Mycophenolic acid AUC(0-12) is predicted by serum albumin and creatinine after kidney transplantation, and the AUC(0-12) may be determined during the early posttransplant period while the patient remains hospitalized with use of a limited sampling strategy to facilitate therapeutic drug monitoring.
authors.affiliation: University Department of Medicine, University of Queensland, Princess Alexandra Hospital, Brisbane, Australia. agj34419@glaxowellcome.co.uk
authors.forename: A G
authors.initials: AG
authors.lastname: Johnson
authors.forename: R J
authors.initials: RJ
authors.lastname: Rigby
authors.forename: P J
authors.initials: PJ
authors.lastname: Taylor
authors.forename: C E
authors.initials: CE
authors.lastname: Jones
authors.forename: J
authors.initials: J
authors.lastname: Allen
authors.forename: K
authors.initials: K
authors.lastname: Franzen
authors.forename: M C
authors.initials: MC
authors.lastname: Falk
authors.forename: D
authors.initials: D
authors.lastname: Nicol
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D019540:Area Under Curve; D003404:Creatinine / Q000097:blood; D004791:Enzyme Inhibitors / Q000097:blood / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D009173:Mycophenolic Acid / Q000097:blood / Q000493:pharmacokinetics*; D012709:Serum Albumin / Q000378:metabolism; D013997:Time Factors
chemical_list: D004791:Enzyme Inhibitors; D012709:Serum Albumin; D003404:Creatinine; D009173:Mycophenolic Acid