Population pharmacokinetics of antifibroblast activation protein monoclonal antibody F19 in cancer patients

AIMS: The population pharmacokinetics of 131I-mAbF19, a radiolabelled murine monoclonal antibody against fibroblast activation protein and a potential antitumour stroma agent, were investigated during two phase I studies in cancer patients. METHODS: 131I-mAbF19 serum concentration-time data were obtained in 16 patients from two studies involving imaging and dosimetry in colorectal carcinoma and soft tissue sarcoma. Doses of 0.2, 1 and 2 mg antibody were administered as 60 min intravenous infusions. The data were analysed by nonlinear mixed effect modelling. RESULTS: The data were described by a two-compartment model. Population mean values were 109 ml h(-1) for total serum clearance, 3.1 l for the volume of distribution of the central compartment, and 4.9 l for the volume of distribution at steady state. Mean terminal half-life was 38 h. Intersubject variability was high, but no patient covariates could be identified that further explained this variability. In particular, there was no influence of tumour type or mAbF19 dose. CONCLUSIONS: The pharmacokinetics of antistromal mAbF19 were well defined in these two studies with different solid tumour types, and were comparable with those of other murine monoclonal antibodies that do not bind to normal tissue antigens or blood cells.     

伏立康唑在肾移植患者中的群体药动学研究

目的：建立肾移植患者服用伏立康唑的群体药动学（PopPK）特征,探究影响伏立康唑药动学参数的因素,为临床个体化给药提供依据。方法：回顾性收集84例肾移植患者进行治疗药物监测的谷浓度和生理病理资料,利用Phoenix NLME软件建模,并用VPC法和Bootstrap法进行内部验证。结果：肾移植患者的伏立康唑的药动学特征符合一级消除一室模型,最终PopPK模型为：表观分布容积V（L）=183.69×[1+（HGB-98）×0.016]×exp（η_V）,清除率CL（L·h^-1）=7.24×[1+（ALB-36）×0.037]×exp（η_CL）。结论：血红蛋白（HGB）对V有显著影响,白蛋白（ALB）对CL有显著影响,所建PopPK模型较稳定,可以较好地描述肾移植患者伏立康唑的药动学特征。     

成年患者替考拉宁群体药动学研究

目的：构建中国成年患者替考拉宁（teicoplanin,TEC）群体药动学（population pharmacokinetics,PPK）模型,探讨TEC药动学参数的影响因素。方法：收集患者的用药信息、血药总浓度、性别、年龄、血清肌酐水平等信息,采用非线性混合效应模型法（nonlinear mixed effect model,NONMEM）建立替考拉宁PPK模型。用图形法、非参数自举法（bootstrap）、正态化预测分布误差法（normalized predictive distribution error,NPDE）进行模型评价。结果：共收集111例成年患者的149个替考拉宁血浆总浓度数据,建立了替考拉宁的一房室PPK模型：CL （L·h^-1）=1.26×（eGFR/82）^0.431,V（L）=83.1,协变量分析显示肌酐清除率（CKD-EPI公式）是影响替考拉宁清除率的重要因素,未发现影响替考拉宁表观分布容积的因素。经验证,最终模型具有良好的拟合优度、稳健率及预测性能。结论：临床可根据患者肌酐清除率（CKD-EPI公式）制定个体化给药方案。     

Population pharmacokinetics of doxorubicin in Indian cancer patients using NONMEM

The population pharmacokinetics of doxorubicin were evaluated based on a mixed-effect model using the NONMEM (VI) program. Doxorubicin in plasma was measured using high-performance liquid chromatography. Plasma concentration measurements (85 plasma samples) of doxorubicin from 28 patients with cancer receiving doxorubicin (with other co-medication) ranging from 20–120?mg by infusion over 1–2?h were analyzed according to a two-compartment model both in FO and FOCE methods. Additive proportional error model was used to describe inter-individual and residual variability. The influence of covariates such as age, body surface area, gender, and clinical laboratory values (SGOT, SGPT) on total body clearance (CL) and volume of distribution (Vd) were examined. No covariate was found to affect the CL and Vd of unchanged doxorubicin. The CL and Vd estimated by FO method were 1.42?L/h and 51.1?L, respectively, and FOCE method are 1.43?L/h and 51.4?L, respectively. The inter-individual variability for CL and Vd and residual variability were 45.8%, 36%, and 12.6%, respectively. The population means and inter-individual and residual variability of pharmacokinetics of doxorubicin were evaluated using the NONMEM program. The results of this study show that the population pharmacokinetic approach could be useful to manage doxorubicin cardio toxicity using sparse data in a clinical setting.     

Population pharmacokinetics of raltitrexed in patients with advanced solid tumours

AIMS: To investigate the population pharmacokinetics of raltitrexed in patients with advanced solid tumours and to identify patient covariates contributing to the interpatient variability in the pharmacokinetics of raltitrexed. METHODS: Patient covariate and concentration-time data were collected from patients receiving 0.1-4.5 mg m(-2) raltitrexed during the early clinical trials of raltitrexed. Data were fitted using nonlinear mixed effects modelling to generate population mean estimates for clearance (CL) and central volume of distribution (V). The relationship between individual estimates of the pharmacokinetic parameters and patient covariates was examined and the influence of significant covariates on the population parameter estimates and their variance was investigated using stepwise multiple linear regression. The performance of the developed model was tested using an independent validation dataset. All patient data were pooled in the total cohort to refine the population pharmacokinetic model for raltitrexed. RESULTS: three-compartment pharmacokinetic model was used to fit the concentration-time data of raltitrexed. Estimated creatinine clearance (CL(CR)) was found to influence significantly the CL of raltitrexed and explained 35% of variability in this parameter, whilst body weight (WT) and serum albumin concentrations (ALB) accounted for 56% of the variability in V. Satisfactory prediction (mean prediction error 0.17 micro g l(-1) and root mean square prediction error 4.99 micro g l(-1)) of the observed raltitrexed concentrations was obtained in the model validation step. The final population mean estimates were 2.17 l h(-1)[95% confidence interval (CI) 2.06, 2.28] and 6.36 l (95% CI 6.02, 6.70) for CL and V, respectively. Interpatient variability in the pharmacokinetic parameters was reduced (CL 28%, V 25%) when influential covariates were included in the final model. The following covariate relationships with raltitrexed parameters were described by the final population model: CL (l h(-1)) = 0.54 + 0.02 CL(CR) (ml min(-1)) and V (l) = 6.64 + 0.08 WT (kg) - 0.16 ALB (g l(-1)). CONCLUSIONS: A population pharmacokinetic model has been developed for raltitrexed in patients with advanced cancer. Pharmacokinetic parameters of raltitrexed are markedly influenced by the patient's renal function, body weight and serum albumin levels, which may be taken into account in dose individualization. The use of influential covariates to guide anticancer dosage selection may result in less variability in drug exposure and potentially a better clinical outcome.     

Population pharmacokinetics of sirolimus in de novo Chinese adult renal transplant patients

AIMS

This study was aimed at determining the population pharmacokinetics of sirolimus and identifying factors that explain pharmacokinetic variability in de novo Chinese adult renal transplant patients.

METHODS

Data were retrospectively extracted from a formal multicentre clinical trial, which was originally designed to evaluate the safety and efficacy of ciclosporin dose reduction and ciclosporin elimination in patients receiving sirolimus. All patients received 12-month treatment, i.e. induction therapy with ciclosporin, sirolimus and corticosteroids during the first 3 months followed by either ciclosporin dose reduction or ciclosporin discontinuation thereafter. Eight-hundred and four sirolimus trough blood concentrations (C₀) from 112 patients were used to develop a population pharmacokinetic model using the nonmem program. A one-compartment model with first-order absorption and elimination was selected as the base model. The influence of demographic characteristics, biochemical and haematological indices, ciclosporin daily dose, ciclosporin C₀ as well as other commonly used co-medications were explored.

RESULTS

The typical values with interindividual variability for apparent clearance (CL/F) and apparent volume of distribution (V/F) were 10.1 l h⁻¹ (23.8%) and 3670 l (56.7%), respectively. The residual variability was 29.9%. CL/F decreased significantly with silymarin or glycyrrhizin co-therapy in hepatically impaired patients, and with increasing total cholesterol levels or ciclosporin C₀. Moreover, CL/F increased nonlinearly with increasing sirolimus daily dose. The median parameter estimates from a nonparametric bootstrap procedure were comparable and within 5% of the estimates from nonmem.

CONCLUSIONS

These results provide important information for clinicians to optimize sirolimus regimens in Chinese renal transplant patients.     

Population pharmacokinetics of tacrolimus in Asian paediatric liver transplant patients

AIMS: The purpose of this study was to describe the population pharmacokinetics of intravenous and oral tacrolimus (FK506) in 20 Asian paediatric patients, aged 1-14 years, following liver transplantation and to identify possible relationships between clinical covariates and population parameter estimates. METHODS: Details of drug dosage histories, sampling times and concentrations were collected retrospectively from routine therapeutic drug monitoring data accumulated for at least 4 days after surgery. Before analysis, patients were randomly allocated to either the population data set (n = 16) or a validation data set (n = 4). The population data set was comprised of 771 concentration measurements of patients admitted over the last 3 years. Population modelling using the nonlinear mixed-effects model (NONMEM) program was performed on the population data set, using a one-compartment model with first-order absorption and elimination. Population average parameter estimates of clearance (CL), volume of distribution (V) and oral bioavailability (F) were sought; a number of clinical and demographic variables were tested for their influence on these parameters. RESULTS: The final optimal population models related clearance to age, volume of distribution to body surface area and bioavailability to body weight and total bilirubin concentration. Predictive performance of this model evaluated using the validation data set, which comprised 86 concentrations, showed insignificant bias between observed and model-predicted blood tacrolimus concentrations. A final analysis performed in all 20 patients identified the following relationships: CL (l h-1) = 1.46 *[1 + 0. 339 * (AGE (years) -2.25)]; V (l) = 39.1 *[1 + 4.57 * (BSA (m2)-0. 49)]; F = 0.197 *[1 + 0.0887 * (WT (kg) -11.4)] and F = 0.197 *[1 + 0.0887 * (WT (kg) -11.4)] * [1.61], if the total bilirubin > or = 200 micromol l-1. The interpatient variabilities (CV%) in CL, V and F were 33.5%, 33.0% and 24.1%, respectively. The intrapatient variability (s.d.) among observed and model-predicted blood concentrations was 5.79 ng ml-1. CONCLUSIONS: In this study, the estimates of the pharmacokinetic parameters of tacrolimus agreed with those obtained from conventional pharmacokinetic studies. It also identified significant relationships in Asian paediatric liver transplant patients between the pharmacokinetics of tacrolimus and developmental characteristics of the patients.     

Netilmicin pharmacokinetics in Hong Kong Chinese cancer patients

OBJECTIVES: To study the pharmacokinetics of netilmicin in Chinese haematology-oncology patients and to determine the pharmacokinetic differences, if any, between this patient subpopulation of Chinese and Caucasians. METHODS: A prospective study was carried out in the adult oncology unit of a major hospital in Hong Kong. During a 6 week period in 1997, all patients commencing on netilmicin therapy were monitored; the patients' demographics, clinical status, netilmicin dose and regimen, and drug administration/blood sampling time were collected. Pharmacokinetic parameters were generated using the USC*PACK package based on specifics of the patients themselves and Caucasians matched for the same patients' parameters using the Bayesian alogrithms. RESULTS: A total of 22 patients were enrolled into the study. Twenty-nine sets of levels were drawn, but only 25 sets from 18 patients (86%) were interpretable. The predicted peak (7.47+/-1.46 microg ml-1 ) and trough levels (1.39+/-0.96 microg ml-1 ) generated by USC*PACK were found to be significantly higher than the levels observed (6.01+/-1.14 microg ml-1 and 0.93+/-0.71 microg ml-1, respectively). Netilmicin clearance, volume of distribution and rate of elimination were all significantly higher in this Chinese subpopulation than those predicted for matched Caucasians. Conclusion Alterations in the netilmicin pharmacokinetics observed in our study population might be related to the disease state and/or ethics of the study patient population. Direct application of Caucasian based population pharmacokinetic parameters to this subgroup of Chinese patients may not be appropriate and may result in underdose.     

Population pharmacokinetics of carbamazepine in Singapore epileptic patients

AIMS: To document the population pharmacokinetics of carbamazepine in patients with epilepsy living in Singapore, the majority of whom are of Chinese origin and others of minority races. METHODS: Steady-state plasma carbamazepine concentration data were gathered during routine care from various hospitals in Singapore for patients with epilepsy. Age, body weight, gender, race, formulation and concurrent medication (for other illnesses) were the fixed effects (covariates) tested simultaneously for their influence on the population mean of carbamazepine clearance, using the nonlinear mixed-effects model, in the NONMEM program. RESULTS: No age, gender, race, or formulation-related effect was found. Body weight (W), age (A) and concurrent medication with phenobarbitone (PB) emerged as the determinants of carbamazepine clearance (CL). The final regression model for carbamazepine clearance found best to describe the data was CL = 40.7 x A(0.494) x W(-1.17) x 1.44PB where CL is in l day(-1) kg(-1), A is in years, W is in kg and PB = 0 for a patient on carbamazepine only and PB = 1 for a patient on concomitant PB. The corresponding interindividual variability (CV%) in CL, described by using an exponential model, was 21.4%, and the residual error, described by using an exponential error model, was 18.2%. Predictive performance of this population covariate model was evaluated by Bayesian forecasting in a similar, but independent cohort of patients. There was no statistically significant bias between predicted and measured plasma carbamazepine concentrations. The population mean value of carbamazepine clearance obtained was similar to that previously reported for patients with a very different ethnic (Caucasians and Blacks) or geographical background (South Africa, Europe and USA). CONCLUSIONS: The derived covariate regression model reasonably predicted concentrations in the separate validation Singapore patient data set. The correlation between carbamazepine clearance and patient-specific characteristics may thus allow dosage adjustment to be made to achieve target steady-state plasma concentrations.     

Population pharmacokinetics of high-dose methotrexate in Chinese pediatric patients with medulloblastoma

Methotrexate (MTX) pharmacokinetics has substantial inter-individual variability and toxicity. In children with medulloblastoma treated with high-dose methotrexate (HD-MTX), the pharmacokinetic properties of methotrexate have not been established. A total of 660 serum samples from 105 pediatric patients with medulloblastoma were included in a population pharmacokinetic (PPK) analysis of methotrexate by using the nonlinear mixed-effects modeling method. The basic one-compartment population pharmacokinetic model was established by NONMEM software and the first-order conditional estimation (FOCE) method, and the final covariate model was obtained by the stepwise regression method. Weight (WT), creatinine clearance (CrCL), and whether the treatment was combined with dexamethasone (DEX) were covariates that had significant effects on the clearance rate (CL) of the model. The pharmacokinetic equation of CL in the final covariate model was as follows: CL_i = 9.23× (1 + 0.0005× (θ_CrCL-105.78)) × (1 + 0.0017× (θ_WT-16)) × e^ηcl,i (L/h), IF (θ_DEX) CL_i = 1.19× CL_i (L/h). The estimation accuracy of all pharmacokinetic parameters were acceptable (relative standard error < 14.74%). The goodness-of-fit diagram and bootstrap tests indicated that the final PPK model was stable with acceptable predictive ability. The PPK model may be useful for determining personalized medication levels in pediatric medulloblastoma patients undergoing HD-MTX therapy.     

Population pharmacokinetics of total and unbound plasma cisplatin in adult patients

AIMS: To investigate the pharmacokinetics of unbound (ultrafilterable) and total plasma platinum using a population approach and to identify patient characteristics that may influence the disposition of the drug. METHODS: Pharmacokinetic and demographic data were collected from adult patients treated with 30-min daily infusions of cisplatin for various malignancies. Unbound and total platinum concentration-time data were analysed using a nonlinear mixed effects model. RESULTS: Data from 43 patients were available for analysis. A linear two-compartment model best described total and unbound platinum plasma concentration-time data. The mean population estimates for total and unbound drug were, respectively, 0.68 and 35.5 l h(-1) for clearance and 21.1 and 23.4 l for central distribution volume (V(1)). Unbound clearance (CL) was dependent on body surface area (BSA) and creatinine clearance, and V(1) was dependent on BSA. The elimination rate constant for plasma-bound platinum (modelled as metabolite formation) was 0.014 h(-1). The pharmacokinetic parameter, f(m)/V(m), a measure of the clearance of unbound platinum due to irreversible plasma binding, was related to serum protein concentration and to the inverse of dose per m(2). The covariate modelling of CL, V(1) and f(m)/V(m) improved the intersubject variabilities associated with these parameters. The final pharmacokinetic models were validated using 200 bootstrap samples from the original datasets. CONCLUSIONS: The results support the conventional dose adjustment of cisplatin based on BSA. They also support the need for a dose reduction in case of renal insufficiency.     

Population pharmacokinetics of ceftazidime in burn patients

AIM: The aim of this study was to characterize, via a population pharmacokinetic approach, the pharmacokinetics of ceftazidime in burn patients who were not in the acute post-injury phase. METHODS: The development of the pharmacokinetic model was based on data from therapeutic drug monitoring (41 patients, 94 samples). The estimation of population pharmacokinetic parameters and the selection of covariates (age, gender, body weight, size of burn and creatinine plasma concentration) that could affect the pharmacokinetics were performed with a nonlinear mixed effect modelling method. RESULTS: No relationship between covariates and the pharmacokinetic parameters was established with the exception of an inverse-linear relationship between creatinine plasma concentration and ceftazidime total clearance. The total clearance of ceftazidime was 2.72 l h-1[coefficient variation (CV) = 56.3%] and the distribution volume of the central compartment was 0.28 l kg-1 (CV = 13.2%) The transfer rate constants (k12, k 21) between the central and peripheral compartments were 0.06718 h-1 (CV = 87.2%) and 0.001823 h-1 (CV = 82.7%), respectively. From these parameters, the total ceftazidime volume of distribution (10.64 l kg-1) was calculated. CONCLUSION: The population parameters were different from those obtained in a previous study performed in fewer patients and in the early period after burn injury. In our study, the lower ceftazidime clearance could be explained by the relative decrease in ceftazidime elimination in relation to the burn area, and the higher ceftazidime volume of distribution in the presence of interstitial oedema, which could act as a reservoir from which ceftazidime returns slowly to the circulation.     

Population pharmacokinetics of teicoplanin in patients with endocarditis

Teicoplanin is a new glycopeptide antibiotic, active against aerobic and anaerobic gram-positive bacteria. The drug is intended for the treatment of systemic infections including endocarditis. In two U.S. clinical safety and efficacy trials, loading doses of 6 to 30 mg/kg doses of teicoplanin were administered initially to 197 patients, followed by once-a-day treatment of approximately the same doses over several weeks. Blood samples were collected sporadically during the study to monitor serum teicoplanin concentrations either by FPIA or microbiological assay. Nonlinear mixed-effects modeling was performed on these data to characterize the population pharmacokinetics of teicoplanin that were best described by a two-compartment model. Patient body weight, concomitant gram-positive drug treatment, and serum creatinine had significant influences on systemic clearance(CL) of the glycopeptide. In addition, body weight affected the volume of distribution of the central compartment(Vc). Other demographic factors such as age, gender, etc., had no effects. The FPIA assay method was more precise than the microbiological assay.     

Population pharmacokinetics of tipifarnib in healthy subjects and adult cancer patients

AIMS: To characterize the population pharmacokinetics of tipifarnib. METHODS: A total of 1083 subjects treated orally with a solution, capsule or tablet formulations of tipifarnib, given as a single dose or as multiple twice-daily doses (range 25-1300 mg) were combined with data from 1, 2 and 24 h intravenous infusions. A total of 3445 concentrations in the index data set were fitted by an open three-compartment linear disposition model with sequential zero-order input into the depot compartment, followed by a first-order absorption process, and lag time, using NONMEM V. The effect of patient covariates on tipifarnib pharmacokinetics was explored. The model was evaluated using goodness of fit plots and relative error measurements for 3894 concentrations in the test data set. Computer simulations were undertaken to evaluate the effect of covariates on tipifarnib pharmacokinetics. RESULTS: Tipifarnib oral bioavailability (26.7%) did not differ between the formulations. The absorption rate from the solution was faster than from the solid forms. Whereas the absorption rate and systemic clearance were more rapid in healthy subjects, the extent of absorption and the steady-state volume of distribution were comparable in cancer patients and healthy subjects. Systemic clearance in cancer patients (21.9 l h-1) exhibited a statistically significant relationship with total bilirubin. The typical volume of the central compartment in cancer patients (54.6 l 70 kg-1) was directly proportional to body weight. The clinical relevance of these covariates in cancer patients is questionable as there was a substantial overlap in simulated concentration-time profiles across a wide range of covariate values. CONCLUSIONS: A population PK approach has been used to integrate data gathered during clinical development and to characterize the pharmacokinetics of tipifarnib. Individualization of dose based on body weight or total bilirubin concentration in adult cancer patients is not warranted.     

老年心衰患者口服地高辛群体药动学模型的建立

目的:应用非线性混合效应模型计算国人老年心衰患者口服地高辛(digxion)群体药动学参数,以促进个体化给药。方法:采用荧光偏振免疫法(FPIA)测定84例老年患者120例次地高辛的血清浓度并收集相关临床指标,运用NONMEM软件建立群体药动学模型。结果:地高辛的药动学符合一室线性开放模型,固定效应参数中,体质量、剂量、血肌酐及尿素氮对参数有影响。最终回归模型中地高辛血药浓度估算值与实测浓度间线性关系良好。结论:用群体药动学模型分析常规监测数据可为老年患者个体化给药提供依据。     

Population pharmacokinetics of dolutegravir in HIV-infected treatment-naive patients

Aim

Dolutegravir is the newest integrase inhibitor approved for HIV treatment and has demonstrated potent antiviral activity in patient populations with a broad range of treatment experience. This analysis aimed to characterize the population pharmacokinetics of dolutegravir in treatment-naive patients and to evaluate the influence of patient covariates.

Methods

A population pharmacokinetic model was developed using a non-linear mixed effect modelling approach based on data from 563 HIV-infected, treatment-naive adult patients in three phase 2/3 trials who received dolutegravir (ranging from 10–50 mg once daily) alone or in combination with abacavir/lamivudine or tenofovir/emtricitabine.

Results

The pharmacokinetics of dolutegravir were adequately described by a linear one compartment model with first order absorption, absorption lag time and first order elimination. Population estimates for apparent clearance, apparent volume of distribution, absorption rate constant and absorption lag time were 0.901 l h^–1, 17.4 l, 2.24 h⁻¹, and 0.263 h, respectively. Weight, smoking status, age and total bilirubin were predictors of clearance, weight was a predictor of volume of distribution and gender was a predictor of bioavailability. However, the magnitude of the effects of these covariates on steady-state dolutegravir plasma exposure was relatively small (<32%) and was not considered clinically significant. Race/ethnicity, HBV/HCV co-infection, CDC classification, albumin, creatinine clearance, alanine aminotransferase or aspartate aminotransferase did not influence the pharmacokinetics of dolutegravir in this analysis.

Conclusions

A population model that adequately characterizes dolutegravir pharmacokinetics has been developed. No dolutegravir dose adjustment by patient covariates is necessary in HIV-infected treatment-naive patients.     

卡培他滨在结直肠癌患者中的群体药动学研究

目的 评价卡培他滨在肠癌患者的群体药动学特征及可能的影响因素.方法 选取56例肠癌(包括结肠癌及直肠癌)患者为研究对象,餐后单次口服卡培他滨0.6 g(0.15 g×4片)后进行多点采集血样,以高效液相色谱-质谱联用法(HPLC-MS/MS)检测受试者给药后血浆中的卡培他滨的血药浓度,以非线性混合效应模型及程序(NON...     

危重症患者替加环素的群体药动学

目的: 建立替加环素在危重症患者中的群体药动学模型,探究该类人群中影响替加环素药动学的因素。方法: 收集静脉使用替加环素的危重症患者的血样,使用高效液相色谱-质谱联用技术测定替加环素的血药浓度。利用NONMEM软件估算替加环素的药动学参数,通过向前纳入法和逆向剔除法建立替加环素群体药动学模型,并对该模型进行验证和评价。结果: 收集54名患者的143个血药浓度建立替加环素的群体药动学模型,静脉给药的一室模型较好地描述替加环素的药动学特征,替加环素的清除率(CL)、表观分布容积(V_d)的群体典型值分别为11.3 L·h^-1和105 L,患者的APACHE Ⅱ评分和年龄对模型有显著影响。结论: 建立的替加环素群体药动学模型预测性能稳定良好,APACHE Ⅱ评分影响替加环素CL,年龄影响替加环素V_d,可为临床替加环素在危重症患者中的个体化给药提供参考。     

氯氮平在中国精神分裂症人群的群体药物动力学研究

本研究旨在考察口服氯氮平 (clozapine) 在中国精神分裂症患者中的群体药物动力学特征, 探讨各项动力学参数与人口统计学因素及CYP1A2酶基因多态性的关系, 通过建立群体药物动力学模型指导临床个体化给药。研究中采集了临床服用氯氮平的183例精神分裂症患者的626份稳态血样本资料, 随机分组为建模组 (168例) 和外部验证组 (15例)。用非线性混合效应模型 (NONMEM) 程序中的一级评估法 (first-order estimation, FO) 对建模组的数据进行分析, 估算清除率 (CL/F)、表观分布容积 (V/F) 和吸收速率常数 (K_a) 的群体值, 并且定量评价人口统计学指标和CYP1A2酶基因型因素对药物动力学参数的影响。建模中单室一级吸收和消除模型能够较好地拟合数据。最终模型包含了经体表面积归一化的单日剂量 (DBSA) 和吸烟 (SMOK) 因素对CL/F的影响。CL/F (非吸烟组)、V/F和K_a的群体典型值分别为28.5 L·h⁻¹ (5.05%)、1 290 L (16.7%) 和2.26 h⁻¹ (fixed), 相应的个体间变异分别为42.2%和10.0%。研究发现吸烟组的清除率有所上升。观测值与预测值之间的残留误差SD为45.8 μg·L⁻¹。     

环孢素A在重症肌无力患者中的群体药动学模型的建立

目的:建立环孢素A在重症肌无力患者中的群体药动学模型,了解影响环孢素A代谢的显著影响因素。方法:回顾性搜集82例服用环孢素A的重症肌无力患者的91个血药浓度及其相关资料,利用SPSS软件和逐步回归法分两次建立群体药动学模型,运用内部验证法对模型进行验证。结果:最终所得模型为Ln(Cl/F)=-4.418+1.598Ln(HGB)+0.008W,表明患者的体质量(W)及血红蛋白(HGB)含量对环孢素A在重症肌无力患者体内的代谢影响较大,模型对血药浓度的预测值与实测值误差为15.96%。结论:用SPSS软件和逐步回归法建立的群体药动学型有一定的预测能力,可以用于指导临床给药,并且在样本量增大时,模型会逐渐完善,此法简单易行,值得推广。