[Evaluation of population pharmacokinetics of cyclosporin A in renal transplantation patients with NONMEM].

NONMEM program was applied for estimating population pharmacokinetic parameters of cyclosporin A (CsA). The influence of body weight, age, sex and drug administration history on clearance were investigated. There were 281 CsA concentrations in whole blood from 60 clinical renal transplantation patients. Samples were analysed by HPLC and FPIA (TDx, Abbott, monoclonal antibody). One compartment open model with first-order absorption and elimination was used to analyse the data. Population mean values of CL(L.h-1), Vd(L), and Ka(h-1) were 59.8, 227, and 1.28 respectively. The interindividual variations of CL, Vd, and Ka were 30.27%, 29.01%, and 75.10% respectively. The residual error was 31.19%. The adjustment value of weight to clearance was 0.03 times with additional model. CL increased 4.31 in male patients, and decreased 12.7 when patients were treated with CsA for a long time.