群体药代动力学及其在新药研究中的应用

近年来新药临床研究越来越重视群体药代动力学的应用。群体药代动力学可以定量地描述病理、生理、合并用药等多种因素对药物代谢的影响，可将PK参数中的各种变异区分开，指导用药方案的调整，从而增强对新药有效性和安全性的评价。本文对群体药代动力学的研究方法及其在新药研究中的应用进行综述．     

中国健康人群西布曲明的群体药动学模型的建立

目的建立中国人群中西布曲明的群体药动学模型。方法 20例男性健康志愿者口服10 mg西布曲明,于服药后0～24 h采集13个采样点采血,采用已验证的HPLC法测定血药浓度。采用非线性混合效应模型（NONMEM）进行群体药动学分析,估算药动学参数。以直观预测检验（Visual predictive check,VPC）和正态预测分布误差（Normalized predictive distribution error,NPDE）,Bootstrap法进行模型性能评估。结果以有吸收时滞的一级吸收和消除的二房室模型为西布曲明的基础药动学模型。协变量筛选未见体重、年龄可显著影响模型参数。残差模型选择指数模型。西布曲明群体药动学参数V1,V2,CL,Q,Ka,Tlag的典型值分别为：7.85 L、2.03 L、1.08 L/h、0.289 L/h、1.95/h、0.187 h;个体间变异分别为42.8%、48.2%、38.5%、27.1%、56.8%和17.8%。Bootstrape、拟合优度、VPC和NPDE的评价结果均表明模型稳定,预测结果可靠。结论用非线性混合效应模型法建立的中国人群中西布曲明的群体药动学模型,结果稳定。     

非线性混合效应模型法在群体药代动力学和群体药效学中的研究进展

群体药代动力学和群体药效学是近年来得到快速发展的药学领域，具有广阔的应用前景。本文对群体药代动力学和群体药效学重要估算方法非线性混合效应模型法进行综述，包括基本概念、常用模型、模型确定方法、数值计算和应用等方面。     

辛伐他汀在年轻健康受试者中的群体药动学研究

目的:考察口服辛伐他汀在年轻健康受试者体内的群体药动学模型。方法:利用中国知网(CNKI)、万方数据库、维普数据库、PubMed电子检索系统等收集与辛伐他汀药动学相关的文献共29篇,以文中涉及到的474名年轻健康受试者为研究对象,运用非线性混合效应模型(NONMEM)建立辛伐他汀的药动学模型。考察年龄、体质量、身高等对药动学参数的影响,并以Bootstrap法进行模型验证。结果:本研究建立了年轻人群口服辛伐他汀一级吸收和消除的一房室药动学模型。体内的辛伐他汀表观清除率(CL/F)、表观分布容积(V/F)和口服吸收系数(Ka)的群体典型值分别为1630L/h、4320L、1.46h-1;年龄、体质量、身高等因素加入模型之后,基本模型并未有明显改善(P>0.05)。结论:年轻人群CL/F和V/F值高于文献中的老年人群值。     

阿托伐他汀在健康受试者中的群体药动学研究

目的建立阿托伐他汀在健康受试者中的群体药动学模型,预测其在健康人群中群体药动学特征,为临床合理用药提供依据。方法计算机检索中国期刊全文数据库(CNKI)、中文科技期刊全文数据库维普(VIP)和万方数字化期刊全文库、Pub Med电子检索系统和美国医学文摘数据库(Medline),提取阿托伐他汀的血药浓度数据,运用非线性混合效应模型(NONMEM)法构建阿托伐他汀的群体药动学模型,考察其在健康受试者体内的群体典型值特征,并以Bootstrap法进行模型验证。结果筛选出11篇文献,共纳入394例受试群体。最终得到的群体药动学参数中表观清除率(Cl/F)和表观分布容积(V/F)的群体典型值分别为255 L/h、3 180 L。结论经Bootstrap验证,阿托伐他汀在健康受试者中的群体药动学模型稳定、可靠,所得参数稳定、可信度较好。     

建立阿奇霉素在中国健康人群中的群体药代动力学模型

目的建立中国人群中阿奇霉素(大环内酯类抗生素)的群体药代动力学模型。方法对20例健康自愿者的血药浓度和生化指标,用非线性混合效应模型法进行群体药代动力学分析,估算药代动力学参数,分析固定效应的影响以及个体内/间的变异,建立群体药代动力学模型。结果口服阿奇霉素呈一级吸收的二室模型,体质量对CL1和CL2及年龄对V1均有影响。结论用非线性混合效应模型法建立的中国人群中阿奇霉素的群体药代动力学模型,结构稳定,预测准确。     

头孢克洛在中国健康志愿者体内的群体药代动力学研究

目的:建立头孢克洛口服给药在健康志愿者体内的群体药代动力学模型,探讨个体因素对代谢反应的影响。方法:基于头孢克洛生物等效性试验数据,应用非线性混合效应模型的群体方法分析头孢克洛口服给药的生物等效性试验数据,估算相关药代动力学参数及变异。结果:头孢克洛在健康志愿者中符合一级吸收的二室模型。药物表观清除率(CL)、中央分布容积(V2)、中央分布容积(V3)、吸收速率常数(KA)的群体典型值分别为0.219L/min、35.9L、598L和0.042min-1。体重对清除率(CL)有显著影响。结论:群体药代动力学最终模型可对个体药代参数做出精确的估计,体重对表观清除率有影响。     

群体药代动力学研究方法

本文着重对群体药代动力学研究方法和研究过程进行介绍,使读者进一步了解非线性混合效应模型方法的特点和具体应用。     

银屑病患者甲氨蝶呤的群体药动学研究

目的:研究银屑病患者甲氨蝶呤(MTX)的群体药动学特征,为临床调整个体化用药提供新途径。方法:收集皮肤科50例银屑病患者单剂量静脉滴注MTX后稀疏血药浓度数据137个,采用荧光偏振免疫法(FPIA)测定,应用非线性混合效应模型(NONMEM)程序一步法估算MTX的群体药动学参数,并定量分析患者年龄、性别、体质量、肌酐清除率、尿素氮等因素对MTX药动学参数的影响。结果:按静脉滴注二房室线性开放模型估算的群体药动学参数中央室清除率(CL)、中央室表观分布容积(Vc)、外周室表观分布容积(Vp)及外周室清除率(Q)分别为10.4L·h-1、11.7L、6.61L及2.8L·h-1,其个体间变异ωCL、ωVc、ωVp、ωQ分别为16.8%、2.8%、11.7%及287.9%。且最终回归模型的MTX浓度估算值与实测值具有一致性。效应中尿素氮对Vp的影响具有显著意义(P>0.05),其协变量参数为(尿素氮/4)-0.845。结论:NONMEM法以二室模型群体参数估算的血药浓度值与实测值有良好相关性,此研究结果有助于MTX的临床合理应用。     

奥特康唑在中国成年健康受试者中的群体药代动力学研究

目的：建立奥特康唑在中国成年健康受试者的高脂餐后群体药代动力学（popPK）模型。方法：30例成年健康受试者在高脂餐后分别单次口服150、450、600 mg奥特康唑,采用液相色谱-串联质谱法（LC-MS/MS）测定血药浓度。使用非线性混合效应模型（NONMEM）分析奥特康唑PK特征,估算popPK参数。结果：以带有吸收迟滞的一级吸收和消除的二室模型作为结构模型,PK参数以体重（WT）异速放大形式进行校正。协变量分析发现,性别（SEX）对外周分布容积有明显影响。中央室清除率（CL1/F）、中央室分布容积（V1/F）、室间清除率（CL2/F）、外周室分布容积（V2 /F）、吸收速率常数（Ka）及迟滞时间（ALAG）的群体典型值分别为0.282 × （WT/70）0.75 L·h-1、200 × （WT/70）1.66 L、22.5 × （WT/70）0.75 L·h-1、333 × （WT/70）■1.66 × （1 + 1.09 × SEX）L、0.252 h-1和0.951 h。CL1/F、V2/F和Ka的个体间变异分别为30.3%、18.8%和69.7%;个体内变异分别为30.8%、24.92 ng·mL-1。结论：本研究所建立的模型稳健,较好地描述了奥特康唑在中国健康成人中的群体药代动力学特征。     

Population pharmacokinetics of arginine glutamate in healthy Chinese volunteers

1.?The present study developed population pharmacokinetic models of arginine and glutamate in healthy Chinese volunteers. Two nonlinear mixed-effect models were developed using NONMEM® software (ICON Development Solutions, Ellicott City, MD) to describe the pharmacokinetic properties and to assess the relevant parameters as well as the inter-individual variability. The potential covariates were screened using stepwise approach and the stability and predictive capability of the models were performed using bootstrap and visual predictive check.

2.?The concentration time curves of arginine and glutamate were best described by a first-order elimination two-compartment model and a nonlinear elimination one-compartment model, respectively. The final parameter estimation of arginine for CL was 44.1?L/h. Q, V₁ and V₂ were 23?L/h, 20.3?L and 46?L, respectively. The final parameter estimation of glutamate for V_max and K_m were 18.8?mg/h and 77.2?mg/L, respectively. V for low dose and high dose was 23.1?L and 36.3?L, respectively.

3.?For arginine, weight was significant covariate on the apparent distribution volume of peripheral compartment. The gain in weight remarkably increases V_2. For glutamate, dose as a significant covariate on the apparent distribution volume was included, subjects received high dose (20?g) have remarkably higher V compared to subjects received low dose (10?g).     

Pharmacokinetics and bioequivalence analysis of amlodipine tablets in Chinese female and male volunteers by HPLC-MS/MS

In the present study, we determined the pharmacokinetics and bioequivalence of two amlodipine tablets in Chinese male and female volunteers using HPLC-MS/MS method. A randomized, two-period and crossover design was conducted in 20 healthy volunteers (14 male subjects and six female subjects). A single dose of either the reference or test formulation was given at the start of each period. Blood samples were collected before drug administration and at 1, 2, 3, 4, 5, 6, 8, 10, 12, 24, 48, 72, 96, 120 and 144 h after drug administration. Plasma amlodipine was detected by HPLC-MS/MS method, and the pharmacokinetic parameters were analyzed using DAS 3.2.8. The developed HPLC-MS/MS method was suitable for the analysis of amlodipine in biological matrix samples. The main pharmacokinetic parameters between the trial preparation and the reference preparation met the regulatory criteria for bioequivalence, and the two preparations were both well tolerated.     

Effect of grapefruit juice on the pharmacokinetics of amlodipine in healthy volunteers

Objective: This study was performed to assess whether coadminstration with grapefruit juice significantly affects the pharmacokinetics of amlodipine, a dihydropyridine class calcium antagonist with slow absorption, distribution and low plasma clearance. The primary objective was to evaluate whether short exposure to grapefruit juice could affect the metabolism of amlodipine to an extent similar to that previously demonstrated for other dihydropyridines (e.g. felodipine, nisoldipine, nitrendipine). Methods: Twelve healthy male volunteers followed a randomised, open crossover study design, comparing the effect of a single oral dose of amlodipine (5 mg) taken together with a glass of grapefruit juice (250 ml) vs water. Blood samples to determine plasma concentration were taken and blood pressure (BP) and heart rate (HR) were measured throughout the study. Results: When amlodipine was coadministered with grapefruit juice, C_max was 115% and AUC(0–72 h) was 116% compared with water, but t_max was not significantly changed. There were no significant differences in BP and HR between the two treatments. A small decrease in diastolic BP, however, was observed in both treatments 4–8 h after drug administration, coinciding with C_max, but this was normalised after 12 h. The BP reduction seen was compensated by a slight increase in HR, which remained throughout the study. Conclusion: An interaction between grapefruit juice and amlodipine was demonstrated. The haemodynamic data showed that a dose of 5 mg was sufficient to achieve a BP reduction in healthy subjects, but the increase in amlodipine plasma concentration seen after intake of grapefruit juice was too small to significantly affect BP or HR. The clinical significance of this food/drug interaction, however, cannot be ignored since there is considerable variation between individuals and a more extensive intake of grapefruit juice might give more pronounced effects. Received: 7 November 1995/Accepted in revised form: 27 March 1996     

Population pharmacokinetics and pharmacodynamics of warfarin in healthy young adults

The population pharmacokinetics and pharmacological response — prothrombin complex activity and factor VII activity — were studied in a group of 48 normal, healthy young volunteers. Population parameter estimates were obtained using a standard two-stage method, a nonlinear mixed effect model (NONMEM) and a two-stage Bayesian method (EM algorithm). A modified sigmoid-Imax model was used to relate the concentration of s-warfarin to the rate of clotting factor synthesis. The three methods produced similar estimates of the population pharmacokinetic parameters, although the standard two-stage method overestimated the contribution of the pharmacokinetic parameters to the interindividual variability. It was not possible to partition the interindividual variability in response between the pharmacodynamic parameters with the NONMEM procedure: the estimates obtained from the EM algorithm were generally in good agreement with those obtained using the standard two-stage approach. The variability in the warfarin concentration contributed at most only 40% of the observed variability in the pharmacological response, and then only for times greater than 96 h after the dose. Most of the variability in the pharmacodynamics was due to interindividual differences in the clotting factor degradation rate constant and C_50,s, the s-warfarin concentration causing a 50% decrease in synthesis rate.     

Population pharmacokinetics of higher-dose mizoribine in healthy male volunteers

The population pharmacokinetic parameters of mizoribine in healthy subjects were estimated using a nonlinear mixed effects model (NONMEM) program. Pharmacokinetic data for population analysis were obtained in the previous study, in which 24 healthy Caucasian male subjects participated in a single-dose (3, 6, 9, 12 mg/kg) study, and 12 subjects participated in a multiple-dose (6, 12 mg/kg/d) study. The mean value of the absorption lag time, absorption rate constant (KA), and apparent distribution volume (V/F) was estimated to be 0.349 h, 0.869 h-1, and 0.834 l/kg, respectively. Oral clearance (CL/F) was modeled with creatinine clearance (CLcr), and the mean value was estimated to be 1.93.CLcr l/h. In addition, pharmacokinetic parameters in individual 36 subjects were obtained from population estimates according to Bayes' theorem. Pharmacokinetic parameters (KA, V/F, and CL/F) in the single-dose study were almost constant at a dose range of 3-12 mg/kg, and were similar to those in the multiple-dose study. These findings indicated that the pharmacokinetics of mizoribine is well described by a simple one-compartment model with first-order absorption.     

The pharmacokinetics of ofloxacin in healthy adult male volunteers

Conclusion In healthy subjects ofloxacin pharmacokinetics were found to be linear in the dose range studied (100–400 mg). The terminal half-time was 7.5–8 h and plasma ofloxacin concentrations were still detectable at 16 and 24 h after administration. The ratio of renal ofloxacin clerance: creatinine clearance was 1.35–1.82 and was not significantly different for the three doses. The non-renal clearance of ofloxacin was 40–60 ml·min^–1, i.e. 20–30% of the total body clearance.Food intake delayed the absorption of ofloxacin but did not significantly modify its elimination.     

来氟米特在中国健康人群中的群体药动学研究

目的：建立来氟米特口服给药在中国健康受试者体内的群体药动学模型,探讨其药动学特征及可能的影响因素。方法：21名健康男性受试者参与本次研究,应用Phoenix NLME（Vision 8.0）软件中的群体模块分析来氟米特口服给药后其代谢产物的血药浓度数据,估算相关药动学参数及其变异情况。结果：来氟米特活性代谢产物特立氟胺在健康志愿者中符合一级吸收的一室模型。吸收速率常数K_a、分布容积V、药物清除率CL的群体典型值分别为0.691 h^-1、12.843 L和0.031 L·h^-1。协变量筛选结果显示,BMI对分布容积V有显著影响（P<0.01）。结论：本研究成功建立了来氟米特在中国健康人群中的群体药动学模型,最终模型可对个体药代参数做出精确的估计,BMI对分布容积V有显著影响。