有限取样法估算中国成年肾移植受者霉酚酸血药浓度-时间曲线下面积

目的建立有限取样方法用于估算霉酚酸(MPA)(免疫抑制药)的AUC。方法31例成年肾移植受者按每次1g,每12h给药1次口服霉酚酸酯(MMF),用线性梯形法计算MPA AUC0-12h,进行相关分析,确定MPAAUC0-12h值的可预测时间点。进行多元线性回归,确定有限取样方案。结果MPAAUC0-12h与服药后0.5h(C0.5,γ=0.60)、1h(C1,γ=0.60)、4h(C4,γ=0.6121)和10h(C10,γ=0.6371)(均P<0.001)血药浓度有较好的相关性,MPAAUC=12.61 0.37C0.5 0.49C1 3.22C4 8.17C10;有84%(26/31)估算AUC误差在10%以内,有97%(30/31)估算AUC误差在20%以内。结论有限取样法可用于估算肾移植受者口服MMF后MPAAUC0-12h。     

有限采样法估算中国肾移植受者霉酚酸体内暴露

摘 要 目的：建立中国肾移植受者霉酚酸（MPA）有限采样法模型,预测采用不同免疫抑制方案的肾移植受者MPA的体内暴露。方法: 首次肾移植术后早期受者108例,根据术后免疫抑制维持方案分为：环孢素(CsA)+ 霉酚酸钠肠溶片(EC MPS)组（n=49）,他克莫司(TAC)+吗替麦考酚酯(MMF)组（n=32）以及TAC+EC MPS组（n=27）。术后14 d在服药前（0 h）及服药后0.5,1,1.5,2,4,6,8,10,12 h采血,应用液相串联质谱法（LC MS/MS）测定MPA血浆浓度。应用多元回归分析建立MPA 0～12 h浓度曲线下面积（AUC 0 12 h）的估算模型。选择相关系数高、临床应用方便的模型应用Bootstrap法及Bland Altman法对其准确性进行验证。结果: 3种免疫抑制方案MPA的AUC0 12存在差异。应用CsA+EC MPS的患者MPA AUC0 12为（54.66±26.86） ng·ml-1·h,显著低于TAC+EC MPS及TAC+MMF组（P<0.01）。经验证,CsA+ EC MPS组较为理想的回归模型为1.32×C1+ 0.54×C1.5+1.25×C2+3.21×C4+12.53,r2=0.75;TAC+ MMF组为1.54×C0.5+2.26×C2+6.60× C4-2.57,r2=0.96;TAC+ EC MPS组为1.21×C1+0.43×C1.5+1.16×C2+4.8×C4+19.32,r2=0.89。结论: MMF或EC MPS在与CsA或TAC联用会存在不同的药动学特征,应当应用不同的有限采样法MPA AUC0 12估算公式,更为合理的评估MPA药物暴露。     

合用他克莫司或环孢素对霉酚酸酯及其代谢产物药动学的影响

目的比较合用他克莫司(FK506)与合用环孢素(Cs A)时霉酚酸酯(MMF)及其代谢产物的药动学差异。方法 20例服用MMF肾移植患者分为2组,分别为合用FK506组或合用Cs A组,于服药前和服药后共11个时间点采取外周静脉血,采用高效液相色谱法测定血浆中MMF及其代谢产物霉酚酸葡萄糖苷(MPAG)和霉酚酸酰基葡萄糖苷(Ac MPAG)浓度,计算药动学参数并进行比较。结果与FK506组相比,Cs A组霉酚酸(MPA)C0较低(1.58 vs 3.40 ng·m L-1),且代谢产物Ac MPAG的C0、Cmax和AUC0¹2 h也显著低于FK506组(C0 0.20 vs 0.45 ng·m L-1,Cmax 0.41 vs 0.72 ng·m L-1,AUC012 h也显著低于FK506组(C0 0.20 vs 0.45 ng·m L-1,Cmax 0.41 vs 0.72 ng·m L-1,AUC0¹2 h 3.04 vs 6.50ng·h·m L-1),2组间MPAG药动学参数差异无统计学意义。结论合用其他免疫抑制剂可能会对MMF及其代谢产物Ac MPAG的药动学产生显著影响。     

霉酚酸酯在肾移植受者的多剂量药代动力学研究

目的 研究肾移植受者口服多剂霉酚酸酯(MMF)后霉酚酸(MPA)的药代动力学特征.方法 24例肾移植受者分为2组,口服MMF 1.5 g/d,于术后第7 d、14 d检测服药后不同时点静脉血MPA浓度,计算药动学参数.结果 术后第7 d、14 Dmpa 峰浓度Cmax分别为(12.3±5.7)和(12.3±5.4)μg/ml(p>0.05);谷浓度C0分别为(0.7±0.5)和(1.8±1.0)μg/ml(P<0.05);Tmax分别为(1.5±0.9)和(1.3±0.6)h(P>0.05);AUC0-12 h分别为(27.0±10.1)和(39.8±16.4)μg·h/ml(P<0.05);MRT0-12 h分别为(3.2±0.8)和(4.0±0.6)h(P<0.05).结论 肾移植受者口服多剂MMF后,MPA在体内存在明显蓄积现象,需要对MPA进行血药浓度监测.     

肾移植受者霉酚酸临床药代动力学研究

目的研究肾移植受者的霉酚酸(MPA)药代动力学。方法 采用高效液相色谱法监测19名肾移植受者术后多剂量口服霉酚酸酯(MMF)后的MPA血药浓度,采用非线性混合效应模型法计算多剂量口服达稳态的MPA药代动力学参数。结果 MPA达峰时间Tmax为1.0 h,峰浓度Cmax为8.3μg/ml,谷浓度Cmin为2.6μg/ml,药时曲线下面积AUC0～12 h为44.9μg.h/ml。MPA药动学参数群体值CL=27.7 L/h,Vd=85.3 L,个体间变异分别为22.0%2、5.7%。结论本研究建立的群体药动学模型可较准确地描述MPA在肾移植受者的药动学特征,其预测能力尚需进一步评估。     

肾移植患者霉酚酸暴露量的影响因素分析及其对血液系统不良反应的预测价值

目的:研究麦考酚钠肠溶片(enteric-coated mycophenolate sodium, EC-MPS)在肾移植患者体内的药动学特征，分析影响其活性成分霉酚酸(mycophenolic acid, MPA)暴露量的临床因素以及MPA暴露量对血液系统不良反应的预测价值。方法:纳入2016年5月至2019年1月于南京医科大学第一附属医院行同种异体肾移植手术或术后常规随访的164例成人患者，采用“EC-MPS+他克莫司+糖皮质激素”免疫抑制方案。采用酶增强免疫分析技术测定MPA浓度，非房室模型计算药动学参数，梯形法计算MPA AUC。采用单因素方差分析、多元线性回归等方法对MPA暴露量与临床变量的相关性进行分析，采用受试者工作特征曲线计算截断值。结果:EC-MPS药动学符合肠溶片的吸收特点，平均MPA AUC为(76.53±28.64) mg·h·L^-1,在目标范围内的比例为40.24%。白蛋白水平与MPA暴露量呈显著正相关，而白细胞水平则与其呈显著负相关。白蛋白水平、MPA AUC预测MPA暴露不足和白细胞减少的界值分别为39.5 g·L^-1     

有限取样法估算中国肾移植患者单个核细胞内 他克莫司的暴露量

目的:建立预测肾移植患者服用他克莫司后外周血单个核细胞(PBMC)内暴露量的有限取样法(LSS)模型.方法:23例接受包括他克莫司在内的三联免疫疗法的肾移植患者,收集给药后0、0.5、1、1.5、2、4、6、8、10、12 h全血标本提取PBMC,采用LC-MS/MS法测定PBMC中他克莫司浓度.以多元线性分析法,获得他克莫司AUC0～12h的LSS估算模型.用Bland-Altman评价模型的预测值和实际测量值的一致性.结果:建立了包含1～4个采样时间点的LSS模型(r2=0.570～0.989).预测他克莫司AUC0～12h的最佳模型为C2-C4-C6-C10(r2=0.989).C0.5-C6模型(r2=0.849)则适用于短期需要监测的门诊患者.结论:由2-4个时间点组成的LSS模型是评估中国肾移植患者他克莫司AUC0～12 h的有效方法,可为临床监测他克莫司细胞内暴露量提供参考.     

霉酚酸对肝移植受者外周血单核细胞IMPDH活性的影响

目的 探讨中国肝移植受者术后早期外周血单核细胞次黄嘌呤核苷酸脱氢酶(IMPDH)活性变化与血浆霉酚酸(MPA)浓度变化之间的相关性。方法 22例肝移植受者术后应用他克莫司、霉酚酸酯(MMF)和糖皮质激素三联免疫抑制方案。移植后早期采集口服MMF前及服药后0.5,1,1.5,2,4,6,8,10,12 h外周血,检测MPA血药浓度,同时测定口服MMF前及后1,2 h外周血单核细胞IMPDH活性。结果 肝移植受者外周血单核细胞IMPDH活性存在个体间差异,与血浆MPA浓度之间呈显著负相关(P<0.05)。与服药前相比,服药后1 h IMPDH活性显著下降(P<0.05)。结论 肝移植受者口服MMF后外周血单核细胞IMPDH活性显著下降,可以作为MPA药效学监测指标。     

有限采样策略应用于中国器官移植患者霉酚酸暴露量估算的研究进展

霉酚酸（mycophenolic acid,MPA）是一种抗代谢免疫抑制药,广泛应用于实体器官移植术后,其具有治疗窗窄、药动学个体差异大等特点,常常需要治疗药物监测（therapeutic drug monitoring,TDM）测定药-时曲线下面积（area under the concentration-time curve,AUC）指导个体化剂量调整。由于监测AUC需密集采样,TDM实施过程中呈现患者依从性差、监测耗时长、所需费用高等缺点。目前临床开展MPA的TDM多采用有限采样策略（limited sampling strategy,LSS）估算MPA-AUC。本文针对LSS估算中国实体器官移植患者MPA暴露量的研究进展进行综述,发现中国人群中MPA的LSS模型主要集中于成人肝、肾移植患者,大部分研究推荐3~4个点估算MPA-AUC;同时免疫抑制方案、霉酚酸剂型、检测方法、采血时间点等导致LSS公式存在差异,临床应用时应针对目标人群选择最佳公式进行MPA-AUC估算。     

霉酚酸在肾移植病人术后首次给药和稳态后的药代动力学

目的 研究免疫抑制剂霉酚酸酯(MMF)的活性代谢产物霉酚酸(MPA)在肾移植病人首次给药和稳态后的药代动力学,评价其蓄积情况。方法选择肾移植病人8例(男3例,女5例),在术后第1天首剂服用MMF1g,按每次1g,每12h给药1次,连续服药7天达稳态,用高效液相色谱法测定MPA血药浓度,血药浓度数据用3P87药代动力学软件,按两室模型拟合并计算药代动力学参数。结果 首次服药及稳态后的药代动力学参数t1/2β分别为12.78±7.29和12.30±5.57 h(P>0.05);Cmax分别为14.29±6.85和19.72±5.83 mg·L-1(P<0.01);AUC0-12h分别为44.57±9.61和64.26±16.59 mg·h·L-1(P<0.01);CL(s)分别为15.51±2.53和11.16±3.53 L·h-1(P<0.01);稳态后,Cmax和AU0-12h与首次服药的比值分别为1.54±0.56和1.48±0.36,均增加了50％。结论MMF连续给药后,MPA在体内存在明显蓄积现象,临床用药时需要对MPA的血药浓度进行常规监测。     

Enteric-coated mycophenolate sodium provides higher mycophenolic acid predose levels compared with mycophenolate mofetil: implications for therapeutic drug monitoring

The delayed release of mycophenolic acid (MPA) from enteric-coated mycophenolate sodium (EC-MPS) may lead to different MPA predose (C0) levels compared with mycophenolate mofetil (MMF). A post hoc analysis was performed on MPA morning predose values assessed in 88 maintenance renal transplant patients from three studies converted from MMF (1000 mg twice a day) to equimolar EC-MPS (720 mg twice a day) or vice versa, both in combination with cyclosporine. The median MPA predose level was approximately 30% higher when patients received EC-MPS (2.40 microg/mL; range, 0.49-39.30 microg/mL) compared with MMF (1.83 microg/mL; range, <0.1-12.80 microg/mL). Rare cases (3.0%) of high MPA C0 levels 15 microg/mL or greater were observed with EC-MPS consistent with a very prolonged release of MPA from this formulation. Both EC-MPS and MMF exhibited a poor correlation between MPA C0 levels and exposure as assessed by MPA area under the curve. Physicians targeting a certain MPA predose level have to be aware of the higher morning C0 levels with EC-MPS, whereas the overall MPA exposure is not different to MMF.     

Omeprazole impairs the absorption of mycophenolate mofetil but not of enteric-coated mycophenolate sodium in healthy volunteers

In 2 crossover studies, 12 healthy volunteers (6 male/6 female) received a single oral dose of mycophenolate mofetil (MMF) 1000 mg or an equimolar dose of enteric-coated mycophenolate sodium (EC-MPS) 720 mg fasting with and without coadministered omeprazole 20 mg bid. The plasma concentrations of mycophenolic acid (MPA) and of the inactive metabolite mycophenolic acid glucuronide (MPA-G) were measured by high-performance liquid chromatography (HPLC). In addition, dissolution of MMF 500 mg or EC-MPS 360 mg tablets was determined using an USP paddle apparatus in aqueous buffer of pH 1 to 7. The bioavailability of MPA following administration of MMF or EC-MPS was similar except for the time to peak concentration, which was longer in the EC-MPS group. Concomitant treatment with omeprazole lowered significantly C(max) and AUC(12h) of MPA following administration of MMF. The pharmacokinetics of EC-MPS was not affected. Dissolution of MMF in aqueous buffer decreased dramatically at pH above 4.5. The EC-MPS tablet was stable up to pH 5. Above, EC-MPS was quantitatively disintegrated and MPS quantitatively dissolved. There is strong evidence that impaired absorption of MMF with concomitant proton pump inhibitors is due to incomplete dissolution of MMF in the stomach at elevated pH.     

Review of the immunosuppressant enteric-coated mycophenolate sodium

Enteric-coated mycophenolate sodium (EC-MPS; myfortic, Novartis Pharma AG) is an advanced formulation delivering mycophenolic acid (MPA). EC-MPS was designed to improve MPA-related upper gastrointestinal adverse events by delaying the release of MPA until reaching the small intestine. At a dose of 720 mg, EC-MPS exhibits equivalent MPA exposure (area under the concentration curve [AUC]) and maximal MPA concentration (C(max)) to mycophenolate mofetil (MMF; CellCept, Roche AG) 1000 mg. The time to maximal MPA concentration (T(max)) for EC-MPS is delayed relative to that for MMF, consistent with a functioning enteric coating. EC-MPS 720 mg b.i.d. has demonstrated therapeutic equivalence to MMF 1000 mg b.i.d. in renal transplant patients. Recent clinical trials have demonstrated that EC-MPS is as effective and safe as MMF in both de novo and maintenance renal transplant patients. Furthermore, studies have confirmed that maintenance patients can be safely converted from MMF to EC-MPS with no compromise of efficacy or safety. EC-MPS therefore presents physicians and patients with a valid alternative MPA therapy with a comparable efficacy and safety profile to MMF.     

Investigation on pharmacokinetics of mycophenolic acid in Chinese adult renal transplant patients

AIMS: To characterize the pharmacokinetics of mycophenolic acid (MPA) in Chinese renal transplant patients. METHODS: Thirty-one renal transplant patients (17 male, 14 female) receiving mycophenolate mofetil (MMF) 1.0 g twice daily were included in this study. A pharmacokinetic study was performed during an interval in dosing after steady state had been reached within 2 months after transplantation. The plasma MPA concentration were measured by high-performance liquid chromatography (HPLC) at 0.5, 1, 1.5, 2, 4, 6, 8, 10 and 12 h after the administration of a single dose. Pharmacokinetic parameters were calculated with 3P97 software. SAS software was used for statistical analysis. Multiple linear regression analysis was used to determine limited sampling approaches. RESULTS: The mean peak plasma concentration (C(max)) and area under the concentration-time curve (AUC(0-12)) were 19.67 +/- 8.21 microg ml(-1) and 52.16 +/- 12.50 microg h ml(-1), but there was large variability in these pharmacokinetic parameters. Regression analysis between each plasma concentration and AUC for the limited sampling strategy of MMF therapeutic drug monitoring demonstrated that each of the concentrations at 0.5, 1, 4 and 10 h was positively correlated with AUC (r = 0.60, P = 0.0004; r = 0.60, P = 0.0003; r = 0.61, P = 0.0003; r = 0.64, P = 0.0001, respectively). The combined use of these four samples explained over 90% of the variance in the total (nine-point) AUC(0-12). A formula was obtained for the assessment of MPA AUC based on four samples: MPA AUC = 12.61 + 0.37 x C(0.5) + 0.49 x C(1) + 3.22 x C(4) + 8.17 x C(10). CONCLUSIONS: Chinese renal transplant patients had higher median AUCs than caucasians and African-Americans. As in other studies, there was large interindividual variability. A limited four-point AUC was in good agreement with the 12-h AUC and provided the basis of a predictive formula.     

Therapeutic drug monitoring of mycophenolate mofetil and enteric-coated mycophenolate sodium in patients with systemic lupus erythematosus

Objective: Mycophenolic acid (MPA), the active form of mycophenolate mofetil (MMF) and enteric-coated mycophenolate sodium (EC-MPS), is used to treat systemic lupus erythematosus (SLE). MMF and EC-MPS pharmacokinetics were examined to devise guidance for therapeutic drug monitoring (TDM) for SLE patients with normal renal function.

Research design and methods: This observational study included 21 patients receiving MMF (1000 mg twice daily) and 14 taking EC-MPS (720 mg twice daily). MPA AUC between 0 and 12 h (AUC_0–12h), C_max, T_max, and 12-h trough concentrations (C_12h) were determined.

Results: Means of dose-normalized MMF– or EC-MPS–MPA C_max were 64.6 ± 25 and 61.4 ± 27.1 h mg/l, respectively. MPA T_max for EC-MPS was longer and more variable than for MMF. MMF-MPA AUC_0–12h and C_12h were correlated (r = 0.78, p = 0.0001), but EC-MPS–MPA C_max and single concentrations were weakly correlated. A limited-sampling strategy (LSS) combining C_max and C_12h gave satisfactory predictive performance to estimate MPA AUC_0–12h after EC-MPS administration.

Conclusions: For TDM in SLE patients with GFR >?60 ml/min/1.73 m², C_12h after MMF ingestion could predict MPA AUC_0–12h, while an LSS around T_max should be used for patients on EC-MPS.     

Mycophenolic acid formulation affects cyclosporine pharmacokinetics in stable kidney transplant recipients

A novel monitoring strategy based on the blood concentration at two hours post-dose (C2) has been recently proposed for the assessment of cyclosporine (CsA) absorption and daily exposure, and therapeutic windows for C2 levels have been identified. These guidelines have been derived from patients given mycophenolate mofetil (MMF) or azathioprine, and never tested in those treated with the enteric-coated formulation of mycophenolic acid (EC-MPS).The authors have compared full CsA pharmacokinetic evaluations in 12 kidney transplant recipients given EC-MPS with those from 20 patients on MMF at months 6, 12, 18 and 24 postsurgery. At month 6 postsurgery, patients on EC-MPS had a shift to the right in the CsA peak concentration as compared to that in patients given MMF, an effect associated with significant differences in CsA Tmax (1.9 +/- 0.3 h vs. 1.5 +/- 0.6 h, P < 0.05), C2 (988 +/- 259 vs. 720 +/- 214 ng/mL, P < 0.01), and C3 levels (539 +/- 119 vs. 435 +/- 119 ng/mL, P < 0.05). Interestingly, the authors found that the majority of patients on EC-MPS had CsA peaking at 2-h postdosing, whereas most of patients on MMF had CsA Cmax at 1 h. Similar results were observed also at months 12, 18, and 24 postsurgery.These findings indicate that the pharmacokinetics of CsA is significantly affected by the concomitant administration of different MPA formulations. This would imply the need of specific algorithms to adequately estimate CsA dose adjustment in patients given, in addition to CsA, EC-MPS or MMF.     

Mycophenolic acid in diabetic renal transplant recipients: pharmacokinetics and application of a limited sampling strategy

Limited sampling strategies may be useful in optimizing therapeutic drug monitoring of mycophenolic acid (MPA). Their use, however, may be limited by several patient factors, including comorbidity. In this study the pharmacokinetics of MPA in diabetic and nondiabetic renal transplant recipients were compared, and it was evaluated whether a limited sampling strategy developed and validated for nondiabetic patients can also be used in diabetic patients. The pharmacokinetics of MPA were analyzed on days 7 and 11 after transplantation in 136 renal transplant patients, among whom 7 patients had diabetes. All patients received cyclosporine and corticosteroids as maintenance immunosuppressive therapy. A limited sampling strategy [AUC (mg x h/L) = 7.182 + 4.607 C0 + 0.998 C0.67 + 2.149 C2] was developed and validated for nondiabetic patients and was subsequently tested for its usefulness in diabetic patients. Diabetic renal transplant patients did not have significantly different dose-normalized MPA area under concentration-time curve (AUC), MPA clearance, or MPA maximum concentration (Cmax). However, in diabetic patients Tmax (time of Cmax, 1.59 hours) was higher than for nondiabetic patients (0.67 hours) on day 11 (P = 0.04). The developed and validated limited sampling strategy performed acceptably, estimating MPA AUC in nondiabetic patients with a mean bias of 0.2 mg x h/L (95% confidence interval from -1.3 to 1.6 mg x h/L). Applying the limited sampling strategy in diabetic patients revealed a mean bias of -1.5 (-5.7, 2.7 mg x h/L). In conclusion, although diabetic renal transplant patients exhibit increased Tmax, this does not affect the accuracy of the limited sampling strategy.     

吗替麦考酚酯胶囊和麦考酚钠肠溶片在早期肾移植患者中的药动学

目的：探讨肾移植术后早期患者口服吗替麦考酚酯胶囊（MMF）和麦考酚钠肠溶片（EC-MPS）的药动学特点,为临床合理用药提供依据。方法：选取26例肾移植患者,按随机数字表法分为MMF组（n=13）和EC-MPS组（n=13）,两组患者分别于术后第1天给予MMF（750 mg q12 h）或EC-MPS（720 mg q12 h）、他克莫司、甲泼尼龙预防排斥反应。于术后第7天的早上服药前及服药后0.5,1,1.5,2,3,4,6,8,10,12 h采集静脉血样3 mL,采用UPLC-UV分析方法测定霉酚酸（MPA）血浆浓度。以 DAS 2.0药动学软件进行药动学分析,所有与剂量相关的两组药动学参数分别进行了剂量校正（C_max/D,C₀/D,AUC_{0-12 h}/D及AUMC_{0-12 h}/D）。用SPSS 17.0软件进行统计学分析。结果：术后第7天MMF和EC-MPS的主要药动学参数t_max分别为（1.54±0.9）h和（2.19±1.56）h（P> 0.05）;C_max/D分别为（5.12±2.83）mg·L^-1·g^-1和（9.51±7.38）mg·L^-1·g^-1（P> 0.05）;AUC_{0-12 h}/D分别为（19.13±7.78）mg·h·L^-1·g^-1和（25.96±11.78）mg·h·L^-1·g^-1（P> 0.05）。两组患者的药-时曲线个体间差异均较大,大部分患者观察到有双峰现象,极个别患者观察到有多峰。MMF组和EC-MPS组患者的MPA-AUC_{0-12 h}低暴露组比例分别为84.6%和46.15%,目标暴露组比例分别为15.4%和46.15%,仅有1例EC-MPS组患者为高暴露组。结论：MMF和EC-MPS在早期肾移植患者体内的药动学个体差异较大,需要常规监测MPA-AUC_{0-12 h},同时可结合C₀作为参考,以指导临床调整用药剂量。MMF和EC-MPS常规剂量下的MPA-AUC_{0-12 h}在早期肾移植患者中偏低,建议增加给药剂量。     

成年与老年肾移植受者霉酚酸药代动力学比较

目的：比较霉酚酸（MPA）在成年与老年肾移植受者药代动力学差异。方法采用高效液相色谱法监测成年组和老年组共21名肾移植术受者术后多剂量口服霉酚酸酯（MMF）达稳态后血液中MPA浓度,采用非房室模型计算MPA药动学参数,并进行组间比较。结果MPA达峰时间：成年（1.0±0.85）h,老年（1.38±1.02）h;峰浓度：成年（13.77±7.49）μg/mL,老年（9.80±6.46）μg/mL;药时曲线下面积AUC 0～12 h：成年（35.41±20.26）μg/（mL·h）,老年（21.62±8.15）μg/（mL·h）。成年组与老年组间峰浓度差异无统计学意义（P＞0.05）, AUC 0～12 h差异有统计学意义（P＜0.05）。结论MMF在体内的吸收有明显的差异;老年人的MMF生物利用度显著低于成年人,服用MMF需要适当增加剂量或缩短用药间隔。     

Limited sampling strategy for the estimation of mycophenolic acid area under the plasma concentration-time curve in adult patients undergoing liver transplant

Mycophenolate mofetil (MMF), the oral prodrug of mycophenolic acid (MPA), is increasingly used in liver transplantation and plays a central role in the immunosuppressive regimen in liver transplantation. To study pharmacokinetic-pharmacodynamic relationships and therapeutic drug monitoring of MPA in the clinical setting, limited sampling strategies have been investigated for the estimation of MPA areas under the curves (AUCs). Thirty-eight adult patients undergoing liver transplant (31 males, seven females) receiving 1.0 g MMF twice daily and concomitant tacrolimus provided a total of 72 pharmacokinetic profiles. Multiple stepwise regression analysis was used to determine the algorithms for limited sampling strategies. Twenty-eight one-, two-, three-, and four-sampling estimation models were fitted (r = 0.288-0.964) to all the profiles using linear regression and were used to estimate MPA AUC0-12h comparing those estimates with the corresponding AUC0-12h values calculated with the linear trapezoidal rule, including all 10 timed MPA concentrations. The four-point estimates at C1h, C2h, C6h, and C8h resulted in the best correlation between estimated AUC and true AUC when using the formula AUC = 6.03 + 0.89C1h + 1.94C2h + 2.24C6h + 4.64 C8h (r = 0.911). Bland and Altman analysis revealed good agreement between estimated AUC and AUC from the full profile. This limited sampling strategy provides an effective approach for estimation of full MPA AUC0-12h in patients undergoing liver transplant receiving concomitant tacrolimus therapy.