A Population Pharmacokinetic And Pharmacodynamic Study Of Warfarin In Patients With Deep Venous Thrombosis

Objective:To establish a population pharmacokinetic model of warfarin in patients with deep vein thrombosis,screening out the covariates that affect the pharmacokinetic parameters of warfarin and to investigate the correlation between pharmacokinetics and pharmacokinetics,in order to provide reference for guiding clinical rational drug useMethods:1)To establish a simple,rapid and reliable HPLC-MS/MS method for the determination of both of SIR warfarin diastereomers in plasmas from patients with deep venous thrombosis with warfarin-d5 as internal standard and the specificity,precision,stability and recovery of this method were verified.2)Collect demographic information,clinical basic information and blood samples of patients that informed consent with clinically diagnosed deep venous thrombosis and who are treated with warfarin,collect clinical pharmacodynamic indicators and combined medication information,extract blood DNA,and perform genotyping detection.To obtain genetic polymorphism information,including CYP2C9*3(1075A>C,rs1057910),VKORC1(-1639G>A,rs9923231),VKORC1(1173C>T,rs9934438),EPHX1(G>A,rs2292566).3)To establish a population pharmacokinetic model of warfarin in patients with deep vein thrombosis by comparing the plasma concentration data of warfarin in the tested patients,the genotypes corresponding to the patient,basic demographic information,and clinical information.NONMEM software was used to screen out the covariates affecting the pharmacokinetic parameters of warfarin and to investigate the pharmacodynamic effectsResults:1)HPLC-MS/MS established in this experiment to detect the concentration of S/R warfarin diastereomers in human plasma,R-warfarin standard curve regression equation is y=0.00982 x+0.00388(r=0.9990);S-warfarin standard curve regression equation is y=0.00939x+0.00212(r=0.9988),the linear range is 5～1500ng·mL-1,and the concentration of all calibration standards is within ± 15%of the indicated value.The minimum limit of quantification is 5 ng.mL’1 and the signal to noise ratio is greater than 10.2)A total of 77 patients with deep venous thrombosis taking warfarin were collected in this study,and a total of 108 blood samples were collected.Two of the patients switched to other anticoagulant drugs.Of the remaining 75 patients,43 were male and 32 were female;the mean age was 61.28 ± 12.7 years;the average height was 1.64±0.08 m;the average body weight was 67.29± 10.62 kg;The BMI value was 24.83 ±3.12 kg/m2.In addition,genotype analysis showed that there were 70 cases no mutation genotypes;5 cases in the single mutant genotype and no double mutation locus was observed in the CYP2C9*3(rs1057910)locus.There were 67 cases no mutation genotypes;7 cases in the single-mutant genotype and 1 cases in the double-site mutant genotype in the VKORC1(rs9923231)locus.There were 65 cases no mutation genotype;10 cases of single mutation genotype and no double site mutation in the VKORC1(rs9934438)locus.There were 42 cases no mutation genotype;27 cases of single mutation genotype and 6 cases of double-site mutation genotype in the EPHX1(rs2292566)locus.3)Based on 75 patients,106 warfarin plasma concentrations,139 INR、PT values and other drug efficacy test values and related information to establish the model.Warfarin pharmacokinetics conforms to the one-compartment model,and the residual model conforms to the additive model.CL=TVCL*COVCL_wt*COVCL_CYP2C93(1)COVcL_Wt=(WT/70)θCL-Wt(2)INR=2.03*CONC/(45.25+ CONC)PT= 23.18*CONC/(36.57+ CONC)APTT=44.59*AUCss/(0.58+ AUCss)where CL/F was described as a function of WT by using equation(1),equation(2)and equation(3),TVCL(0.441 L/h)is the population parameter of CL,θCL_wt is 0.98,and θCL_C2C93 is-0.445,and CONC is the predicted blood concentration of S-warfarin in patients,AUCss is the area under the steady-state plasma concentration-time curve.Conclusion:1)HPLC-MS/MS established in this study to detect the concentration of S/R warfarin diastereomers in human blood has been verified by comprehensive method,with good specificity and sensitivity,which can quickly and accurately determine the concentration of warfarin diastereomers in human plasma and the obtained results are accurate and reliable,and meet the general pharmacokinetic and biological sample analysis and determination.2)This study is the first to study the population pharmacokinetic model of warfarin in patients with deep vein thrombosis based on NONMEM.The diagnosis results are stable and good.The results of covariate study showed that the gene polymorphism of body weight and CYP2C9＊3 locus.It may affect the pharmacokinetic parameters of warfarin in patients with deep vein thrombosis,and provide a methodological reference for guiding clinical rational drug use.