title: A six-hour extrapolated sampling strategy for monitoring mycophenolic acid in renal transplant patients in the Indian subcontinent.
abstract: BACKGROUND
  Therapeutic drug monitoring for mycophenolic acid (MPA) is increasingly being advocated. The present therapeutic range relates to the 12-hour area under the serum concentration time profile (AUC).However, this is a cumbersome, tedious, cost restricting procedure. Is it possible to reduce this sampling period?
  
  
  OBJECTIVE
  To compare the AUC from a reduced sampling strategy with the full 12-hour profile for MPA.
  
  
  METHODS
  Clinical Pharmacology Unit of a tertiary care hospital in South India. Retrospective, paired data.
  
  
  METHODS
  Thirty-four 12-hour profiles from post-renal transplant patients on Cellcept were evaluated. Profiles were grouped according to steroid and immunosuppressant co-medication and the time after transplant. MPA was estimated by high performance liquid chromatography with UV detection. From the 12-hour profiles the AUC up to only six hours was calculated by the trapezoidal rule and a correction factor applied. These two AUCs were then compared.
  
  
  METHODS
  Linear regression, intra-class correlations (ICC) and a two-tailed paired t-test were applied to the data.
  
  
  RESULTS
  Comparing the 12-hour AUC with the paired 6-hour extrapolated AUC, the ICC and linear regression(r2) were very good for all three groups. No statistical difference was found by a two-tailed paired t-test. No bias was seen with a Bland Altman plot or by calculation.
  
  
  CONCLUSIONS
  For patients on Cellcept with prednisolone +/- cyclosporine the 6-hour corrected is an accurate measure of the full 12-hour AUC.
authors.affiliation: Clinical Pharmacology Unit, Christian Medical College, Vellore, Tamil Nadu, India. clinpharm@cmcvellore.ac.in
authors.forename: D H
authors.initials: DH
authors.lastname: Fleming
authors.forename: B S
authors.initials: BS
authors.lastname: Mathew
authors.forename: G T
authors.initials: GT
authors.lastname: John
authors.forename: S J
authors.initials: SJ
authors.lastname: Chandy
authors.forename: J
authors.initials: J
authors.lastname: Manivannan
authors.forename: V
authors.initials: V
authors.lastname: Jeyaseelan
mesh_terms: D000293:Adolescent; D000328:Adult; D019540:Area Under Curve; D016903:Drug Monitoring / Q000379:methods*; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood* / Q000493:pharmacokinetics*; D007194:India; D016030:Kidney Transplantation; D008875:Middle Aged; D009173:Mycophenolic Acid / Q000097:blood* / Q000493:pharmacokinetics*; D013997:Time Factors
chemical_list: D007166:Immunosuppressive Agents; D009173:Mycophenolic Acid