title: Population pharmacokinetics of tacrolimus and CYP3A5, MDR1 and IL-10 polymorphisms in adult liver transplant patients.
abstract: OBJECTIVE
  Tacrolimus, an immunosuppressant widely used after liver transplantation, is characterized by a large inter-individual variability in its pharmacokinetics. The aim of this study was to perform population pharmacokinetic analysis of oral tacrolimus in liver transplant recipients and clarify the potential role of CYP3A5, MDR1 and IL-10 genetic polymorphisms in the variability of population pharmacokinetic parameters.
  
  
  METHODS
  Tacrolimus blood concentration data (n = 1106) were collected from 104 full liver transplant patients and were analysed using a non-linear mixed-effects modelling program (nonmem). The CYP3A5*3, MDR1 G2677T/A and C3435T genetic polymorphisms were determined using polymerase chain reaction (PCR)-restriction fragment length polymorphism analysis. The IL-10 G-1082A variant was studied by allele-specific PCR method.
  
  
  CONCLUSIONS
  The liver function in patients as indicated by the total bilirubin level (TBIL) and different CYP3A5*3 genotypes in donors (CYPD) and recipients (CYPR) were observed to influence tacrolimus pharmacokinetic parameter of apparent clearance (Cl/F). The final regression model can be expressed as Cl/F = 15.9 - 1.88 TBIL + 7.65 CYPD + 7.00 CYPR. The relative standard errors (%RSE) of the parameter estimation were lower than 30% and the residual variability of tacrolimus trough blood concentration was 2.81 ng/mL. No significant effect of MDR1 and IL-10 polymorphisms was observed on population pharmacokinetic parameter of tacrolimus within 175 days after liver transplantation.
  
  
  CONCLUSIONS
  The TBIL in patients and CYP3A5*3 genetic polymorphism in both donors and recipients contribute to the inter-individual variability of oral tacrolimus apparent clearance in Chinese adult liver transplant patients.
authors.affiliation: Department of Pharmacology, Basic Medical School, Health Science Centre, Beijing (Peking) University, Beijing, China.
authors.forename: D
authors.initials: D
authors.lastname: Li
authors.forename: W
authors.initials: W
authors.lastname: Lu
authors.forename: J-Y
authors.initials: JY
authors.lastname: Zhu
authors.forename: J
authors.initials: J
authors.lastname: Gao
authors.forename: Y-Q
authors.initials: YQ
authors.lastname: Lou
authors.forename: G-L
authors.initials: GL
authors.lastname: Zhang
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D000328:Adult; D000368:Aged; D000483:Alleles; D019540:Area Under Curve; D044466:Asian People; D001663:Bilirubin / Q000097:blood; D002681:China; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D016753:Interleukin-10 / Q000235:genetics*; D008099:Liver / Q000378:metabolism; D016031:Liver Transplantation; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D008954:Models, Biological; D011110:Polymorphism, Genetic; D016559:Tacrolimus / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D007166:Immunosuppressive Agents; D016753:Interleukin-10; D003577:Cytochrome P-450 Enzyme System; C510164:CYP3A5 protein, human; D051544:Cytochrome P-450 CYP3A; D001663:Bilirubin; D016559:Tacrolimus