液-质联用测定大鼠血浆中氯吡格雷羧酸代谢物SR26334浓度及其药动学研究

目的建立大鼠血浆氯吡格雷羧酸代谢物SR26334的液-质联用检测方法,研究氯吡格雷代谢物SR26334的药代动力学。方法血浆经乙酸乙酯和正己烷提取,以ZORBAX SB-C18为色谱柱;流动相为乙腈-0.1%甲酸,流速为0.3mL·min-1;通过电喷雾离子源,以多反应监测方式(MRM)进行离子检测,通道为(m/z)为m/z 308.1→m/z 198.1(SR26334)和m/z 383.2→337.0(氯雷他定)。6只雄性大鼠单剂量灌胃给予7.5mg·kg-1氯吡格雷,分别在给药后多点尾静脉采血;用该方法检测血浆中SR26334的浓度。用DAS(数据采集系统)计算药代动力学参数。结果 SR26334浓度在1～5000ng·mL-1范围内线性关系良好(r=0.9991);最低检测限为1ng·mL-1;方法回收率大于97%,提取回收率大于85%,日内和日间RSD小于8%。结论本方法准确可靠、简便快速,适用于大鼠血浆SR26334浓度的测定及其药代动力学研究。     

硫酸氢氯吡格雷片在PCI术后患者体内的药动学研究

目的建立HPLC法测定人血清中氯吡格雷及其羧酸代谢物SR26334,研究硫酸氢氯吡格雷片在PCI术后患者体内的药动学情况。方法采用CLC-ODS色谱柱(250 mm×4.6 mm,5μm);流动相:乙腈–0.1%甲酸溶液(60∶40);检测波长:235 nm;体积流量:1.0 m L/min;柱温:40℃;进样体积10μL。收集到7例PCI术后口服硫酸氢氯吡格雷片75 mg/d超过7 d的患者,在当天早上服药后0、0.5、1、1.5、2、3、4、6、8、12、16、24 h从静脉采血,检测氯吡格雷和SR26334的血药浓度,制备平均药时曲线,使用DSA 2.0计算氯吡格雷和SR26334的药动学参数。结果氯吡格雷、SR26334在0.2~8μg/m L线性关系良好,定量限均为0.2μg/m L。绝对、相对回收率均大于80%,日内、日间精密度RSD值均小于5%。氯吡格雷、SR26334的C_(max)、t_(max)、t_(1/2)分别为(65±0.57)、(0.77±0.22)μg/m L,(3.02±0.69)、(2.88±0.48)h,(7.66±3.65)、(8.52±3.37)h。结论本方法简便、快速,适用于硫酸氢氯吡格雷片血药浓度的临床监测。     

氯吡格雷在人血浆浓度的液质联用测定法

目的建立测定人血浆中氯吡格雷(抗心肌及抗脑梗死药)血药浓度的HPLC/MS/MS法。方法血浆样品用叔丁基甲醚提取,内标为噻氯匹定;色谱柱用X-Terra MS C_(18)(2.1 mm×50 mm,5μm),柱温30℃,流动相:乙腈-水(含10 mmol·L~(-1)醋酸铵,调pH为4.0)为70:30,流量为0.3 mL·min~(-1);质谱用ESI离子源,定量分析的离子反应分别为m/z 322→z 212 (氯吡格雷),m/z 264→m/z 154(内标噻氯匹定)。结果氯吡格雷的线性范围为10×10~4～1.2×10~4pg·mL~(-1)(γ=0.9993),日内、日间RSD均小于10%,提取回收率约为80%。结论该方法快速、准确、灵敏度高,可用于氯吡格雷血药浓度测定。     

液相色谱-质谱联用法测定人血浆中氯吡格雷及其3种代谢产物的浓度

目的:建立同时测定人血浆中氯吡格雷(CLP)及其中间代谢产物2-氧-氯吡格雷(2-O-CLP)、非活性代谢产物氯吡格雷羧酸代谢物(CLPCA)和活性代谢产物氯吡格雷硫醇代谢物(CLPTM)浓度的方法。方法:选取陆军军医大学第一附属医院确诊为脑卒中的90名患者,早晨空腹口服1片氯吡格雷片(75 mg/片),于服药2 h后采集血样,将CLPTM经2-溴-3’-甲氧基苯乙酮衍生形成CLPTM-D后与其余3种待测物一起通过乙腈蛋白沉淀提取后,采用液相色谱-串联质谱法(LC-MS/MS)测定其浓度。色谱柱为Agilent poroshell 120 EC-C18,流动相为0.1%甲酸的乙腈溶液-0.1%甲酸水溶液(90∶10,V/V),采用多反应监测模式进行正离子检测,检测离子对分别为CLPCA质荷比(m/z)308.1→198.1、CLP m/z 322.3→212.0、2-O-CLP m/z 338.3→155.0、CLPTM-D m/z504.4→354.1、内标噻氯吡啶m/z 264.0→154.1。结果:CLPCA、CLP、2-O-CLP、CLPTM-D和内标的保留时间分别为2.01、3.32、2.83、2.68、1.87 min,CLPCA、CLP、2-O-CLP、CLPTM-D检测质量浓度的线性范围分别为100～10 000、0.2～20、0.3～30、0.5～50ng/mL(r均≥0.999 5),日内、日间精密度试验的RSD均≤9.5%(n=5),准确度为93.5%～98.9%(n=5),提取回收率为85.4%～95.9%(n=5),基质效应的CV为2.7%～6.2%(n=5)。稳定性(-80℃放置3个月、3次冷冻-解冻循环、4℃放置8 h)试验中,CLPCA、CLP、2-O-CLP和CLPTM-D的RE均≤10.0%(n=5)。结论:建立的LC-MS/MS法特异性强,测定结果准确可靠,可用于检测人血浆中CLP及其3种代谢产物的浓度。     

雷贝拉唑对氯吡格雷在大鼠体内药动学的影响

目的 研究雷贝拉唑对氯吡格雷在大鼠体内的药动学的影响。 方法 将16只大鼠随机分成2组,单独给予氯吡格雷(Ⅰ组)和联用雷贝拉唑(Ⅱ组),于给药后不同时间点采集血样,HPLC-DAD法测定血浆中氯吡格雷代谢产物SR26334的浓度,用DAS药动学软件对SR26334血药浓度-时间数据采用非房室模型分析,求得氯吡格雷在大鼠体内主要的药动学参数,并对其进行统计分析。 结果 与单用组比较,雷贝拉唑组的主要药动学参数(AUC_(0-48),AUC_(0-∞),MRT_(0-48),t_1/2,CL_z/F,C_max 差异均无统计学意义(P > 0.05),t_max 由(1.17 ± 0.41)h 减少为(0.58 ± 0.20)h(P < 0.01)。结论 雷贝拉唑对氯吡格雷在大鼠体内动力学过程无影响,但有加快氯吡格雷体内代谢为SR26334 的速度,但对于其代谢程度没有显著性影响。     

HPLC-MS法测定鸡肉中氯吡多的残留

目的:建立鸡肉中氯吡多残留的 HPLC—MS 检测方法。方法:鸡肉组织经乙腈提取,用氧化铝柱和葡聚糖凝胶阴离子交换柱净化,洗脱液浓缩后用含内标物对乙酰氨基酚的甲醇溶液溶解。采用 Ultimate XB—C_(18)色谱柱(100 mm×4.6 mm,5μm),以0.1%甲酸溶液-乙腈(85:15)作为流动相;定量离子通道为[M H]~ m/z 192(氯吡多)和 m/z 152(内标),以同位素离子通道 m/z 194,196,192中氯吡多的峰面积比值作为定性依据。结果:氯吡多的线性范围为20～400 ng·mL~(-1)(r=0.9994);将氯吡多以0.005,0.010,0.015 mg·kg~(-1)。分别添加到空白鸡肉组织中,测得回收率分别为84.0%,86.8%,84.8%,RSD 均小于7%;用该方法测定鸡肉中氯吡多残留的检测限、CCα和 CCβ分别为0.0002,0.011,0.012 mg·kg~(-1)。结论:该方法专属性好、灵敏度高,可用作鸡肉中氯吡多残留的检测。     

经皮冠状动脉介入术术后病人 CYP2C19*2、CYP2C19*3和 PON1基因多态性与氯吡格雷血药浓度及疗效的相关性分析

目的探讨经皮冠状动脉介入术( PCI)术后病人 CYP2C19*2、CYP2C19*3及 PON1基因多态性与氯吡格雷血药浓度及疗效的相关性。方法采用定时定量焦磷酸测序技术检测 CYP2C19*2、CYP2C19*3及 PON1基因型。使用反相高效液相色谱法(RP?HPLC)法,以艾司唑仑为内标,测定氯吡格雷、羧酸氯吡格雷( SR26334)血药浓度。结果共纳入 51例 PCI术后病人,果显示 CYP2C19快代谢型血药浓度( 1.09±0.61)μg/mL与慢代谢型 SR26334血药浓度( 1.54±0.48)μg/mL之间差异有统计学意结义( P＝0.038 9)PON1(126C>G)野生型( CC型)病人 SR26334血药浓度( 1.45±0.63)μg/mL与突变型( CG+GG型)病人 SR26334血药浓度( 1.09±0.3,2)μg/mL差异有统计学意义( P＝0.0408)。 SR26334峰浓度与终点事件相关性分析中可见,正常组病人血药浓度( 1.51±0.48)μg/mL VS心血管事件组病人血药浓度( 1.06±0.65)μg/mL差异有统计学意义( P＝0.0481)CYP2C19基因型与终点事件的发生无明显相关。结论基因检测和血药浓度检测可为 ACS病人 PCI术后个体化抗血小板治疗,方案的制订提供依据,可作为临床药师开展药学服务的切入点之一。     

液-质联用法测定人血浆伊潘立酮的药物浓度

目的:建立高效液相串联质谱方法测定人血浆中伊潘立酮的药物浓度。方法:方法色谱柱为Kromasil 60-5CN(100mm×2.1mm,5μm),流动相:乙腈与5mmol·L-1醋酸铵缓冲液(含0.1%甲酸)体积比为35∶65,流速为0.3mL·min-1,吡格列酮为内标,采用电喷雾离子源,以多反应监测(MRM)方式进行正离子检测。用于定量分析的离子分别为m/z 427.2→m/z261.2(伊潘立酮),m/z357.2→m/z133.8(吡格列酮,内标)结果:伊潘立酮的血浆浓度在20～20 000pg·mL-1范围内线性良好,定量下限为20pg·mL-1,日内精密度<3%,日间精密度<9%,回收率为96.9%～101%。结论:该法操作简单,灵敏,准确,重现性好,适用于伊潘立酮人体药动学研究及生物等效性研究。     

PON1基因Q192R多态与氯吡格雷临床疗效及安全关联性的Meta分析（英文）

目的系统性评价PON1基因Q192R多态与氯吡格雷临床疗效及安全的关联性,以期为其临床研究及应用提供有效证据。方法计算机检索Embase、Medline、Pub Med、Web of Science、CNKI、万方、VIP、CBM数据库查找研究PON1基因Q192R多态与氯吡格雷临床疗效及安全相关性的临床研究,文献检索时限均从建库至2014年10月24日。对符合条件的研究,由两位研究者按照纳入和排除标准,独立筛选文献、提取资料、评价质量,并交叉核对后,采用Stata12.0软件对氯吡格雷抵抗、出血、主要不良心血管事件(MACE)、血小板反应活性及其抑制率进行Meta分析。结果共纳入32篇文献,包含34个研究(n=26 831)。Meta分析结果显示,PON1基因Q192R多态与服用氯吡格患者发生氯吡格雷抵抗和出血无关,氯吡格雷抵抗:192QR+192RR vs.192QQ[OR=0.92,95%CI(0.58~1.48),P=0.735],192RR vs.192QR+192QQ[OR=1.06,95%CI(0.87~1.29),P=0.583],192RR vs.192QQ[OR=1.00,95%CI(0.56~1.79),P=0.995];出血:192QR+192RR vs.192QQ[OR=0.92,95%CI(0.74~1.16),P=0.489],192RR vs.192QR+192QQ[OR=0.75,95%CI(0.56~1.02),P=0.066],192RR vs.192QQ[OR=0.70,95%CI(0.48~1.02),P=0.066)];同样,PON1基因Q192R多态对服用氯吡格雷患者发生MACE无影响,MACE:192QR+192RR vs.192QQ[OR=0.85,95%CI(0.71~1.03),P=0.092],192RR vs.192 QR+192QQ[OR=0.90,95%CI(0.71~1.15),P=0.406],192RR vs.192QQ[OR=0.89,95%CI(0.63~1.27),P=0.521]。此外,PON1基因Q192R多态可能增加服用氯吡格雷患者治疗中血小板活性反应及降低其抑制率,血小板反应活性抑制率:192QR+192RR vs.192QQ[WMD=-1.04,95%CI(-4.83~2.75),P=0.591],192RR vs.192QR+192QQ[WMD=-3.67,95%CI(-7.84~0.50),P=0.084],192RR vs.192QQ[WMD=-4.99,95%CI(-9.96~0.02),P=0.049];血小板反应活性:192QR+192RR vs.192QQ[WMD=0.85,95%CI(-0.47~2.16),P=0.209],192RR vs.192QR+192QQ[WMD=0.57,95%CI(-2.28~3.43),P=0.694],192RR vs.192QQ[WMD=2.12,95%CI(-1.42~5.65),P=0.240]。结论 PON1基因多态尽管可能影响血小板反应活性,但对服用氯吡格雷患者发生氯吡格雷抵抗、出血和MACE无影响,总之,PON1基因多态对服用氯吡格雷患者的疗效及安全性无影响。     

用液相色谱-质谱联用法同时测定人血浆中阿司匹林和氯吡格雷的浓度

目的：建立液相色谱-质谱联用（LC-MS）法同时测定人血浆中阿司匹林和氯吡格雷的浓度。方法 ：以苯甲酸为内标,色谱柱为Kromasil C18柱（150mm×4.6mm,5μm）;流动相为甲醇-0.2%乙酸溶液（60∶40）,流速为0.8ml/min。采用正离子选择性离子监测模式进行检测,参比离子m/z分别为322.1（氯吡格雷）、178.9（阿司匹林）和121.1（苯甲酸）。结果：阿司匹林和氯吡格雷分别在10~5000ng/ml和1~200ng/ml的浓度范围内呈良好线性关系（r≥0.996 8）,低、中、高浓度阿司匹林（40、800、4000ng/ml）和氯吡格雷（4、40、160ng/ml）的日内、日间RSD均〈15%,提取回收率为82.4%~92.4%（n=5）,稳定性良好。结论：本方法准确、灵敏,可同时测定人血浆中阿司匹林和氯吡格雷的浓度。     

HPLC-MS法测定氯吡格雷酸人体尿药浓度及氯吡格雷酸经尿排泄研究

目的：建立测定氯吡格雷酸人体尿药浓度的高效液相色谱-质谱联用方法,并通过监测硫酸氢氯吡格雷片经健康受试者口服后其主要Ⅰ相代谢物氯吡格雷酸尿药浓度的经时变化过程,考察氯吡格雷酸经尿排泄特征。方法：色谱采用Lichrospher C18柱（150 mm×2.1 mm,5μm）,以甲醇-10 mmol·L^-1醋酸铵水溶液（含0.1%甲酸）（42∶58）为流动相。质谱采用电喷雾离子源四级杆质谱,以选择性离子监测方式进行正离子检测。6名健康受试者单次口服硫酸氢氯吡格雷片75 mg后,定时收集尿样。采用甲醇直接稀释法处理尿样后,评价氯吡格雷酸经尿排泄特征。结果：氯吡格雷酸在4.780～9 559μg·L^-1质量浓度范围内线性关系良好,平均回收率大于93.4%。受试者服药后0～2小时间,氯吡格雷酸经尿排泄速率最大;36小时内有（1.1±0.5）%的氯吡格雷以氯吡格雷酸形式从尿中排出。结论：该测定方法符合生物样品分析要求;氯吡格雷在体内以氯吡格雷酸形式经尿排泄迅速,24小时内基本排泄完全。     

Pharmacokinetics and platelet aggregation inhibitory effects of a novel intravenous formulation of clopidogrel in humans

1. PM103 is an intravenous formulation of clopidogrel being developed as an alternative to oral clopidogrel to provide for dosing flexibility in the emergent clinical setting. The present first-in-human study assessed the pharmacokinetic and pharmacodynamic effects of PM103 and its safety in 144 healthy human subjects. 2. The present was a randomized open-label parallel-group trial. Single intravenous doses of PM103 (0.1, 1.0, 10, 30, 100 or 300 mg) were administered to each group (n = 24 subjects per group). Platelet aggregation was assessed at baseline and then 15 and 30 min and 2, 5 and 24 h after drug administration. Determination of plasma concentrations of clopidogrel, clopidogrel carboxylic acid metabolite and the clopidogrel thiol metabolite were assessed at baseline and at 1, 5, 10, 20 and 30 min and 1, 2, 3, 4, 6, 8, 12 and 24 h after drug administration. 3. PM103 produced a rapid, persistent and dose-related inhibition of platelet aggregation. The onset of the ant platelet effect paralleled the appearance in plasma of the clopidogrel thiol active metabolite. PM103 was well tolerated and no subjects discontinued treatment because of adverse events. 4. These data suggest that PM103 may be a suitable alternative to oral clopidogrel for patients in whom the desired clinical management would include administration of clopidogrel after coronary angiography but prior to percutaneous coronary intervention.     

Determination of clopidogrel main metabolite in plasma: a useful tool for monitoring therapy?

This study was performed to determine whether analysis of clopidogrel and its main carboxylic acid metabolite in plasma provides additional information about the wide variability of platelet aggregation inhibition in clopidogrel-treated patients with peripheral arterial occlusive disease. Consecutive outpatients (n = 56) with stable peripheral arterial occlusive disease treated with 75 mg clopidogrel daily, without co-administration of aspirin, were investigated. With use of a standardized questionnaire, the time of drug intake was documented. Blood sampling was performed within 24 hours after the most recent drug intake. Platelet function was measured by optical aggregometry using adenosine diphosphate (ADP) (2 mumol/L) as the agonist. Plasma concentrations of clopidogrel and its main metabolite, clopidogrel carboxylic acid, were quantitated using high-performance liquid chromatography analysis coupled to mass spectrometry. In 95% (53/56) of patients, clopidogrel carboxylic acid was detected. In 40% (22/56) of patients, the ADP-induced aggregation response was within the normal range despite clopidogrel treatment. In 14% (3/22) of these patients, neither clopidogrel nor its main metabolite could be detected. Two of these patients agreed to ingest 75 mg/d clopidogrel under observation and to undergo blood sampling after 2, 12, and 24 hours. Clopidogrel carboxylic acid and a significant inhibition of platelet aggregation were detected even after 24 hours in both patients, confirming noncompliance as the reason for the lack of inhibition of ADP-induced platelet aggregation observed in the initial measurements. In the subgroup of patients who had taken clopidogrel within 4 hours before blood sampling, a large range of carboxylic acid concentrations was detected, indicating a high variability of drug metabolism among patients. In conclusion, determining clopidogrel metabolite plasma concentrations could be a useful tool for identifying poor compliance and variable metabolism in clopidogrel-treated patients. Nevertheless, in the majority of clopidogrel-treated patients, the variability of platelet response is not caused by noncompliance.     

Very slow chiral inversion of clopidogrel in rats: a pharmacokinetic and mechanistic investigation.

Clopidogrel hydrogen sulfate, a thienopyridine derivative, is an ADP receptor antagonist that inhibits platelet aggregation. Clopidogrel is an enantiopure carboxylic ester of S-configuration. The R-enantiomer is devoid of antithrombotic activity and can provoke convulsions at high doses in animals. During preclinical safety evaluation, the possible chiral inversion of clopidogrel has, therefore, been investigated in vivo after repeated oral administration of different dose levels of clopidogrel to male and female rats. Due to rapid metabolism in the liver and low plasma levels of unchanged drug, possible chiral inversion was assessed by monitoring the plasma concentrations of the carboxylic acid metabolites, i.e., the (S)- and (R)-acid, by means of a stereoselective assay. The production of 4 to 8% of (R)-acid was observed. This could be the result of chiral inversion of either clopidogrel or its main metabolite, the (S)-acid. Thus, the possibility of nonenzymatic and enzymatic inversion of clopidogrel and its carboxylic acid metabolite was studied in vitro by chiral HPLC and (1)H NMR. Nonenzymatic chiral inversion of clopidogrel at 37 degrees C in 0.1 M phosphate buffers could be observed but was found to be slow, with estimated half-lives of 7 to 12 days, depending on the pH. The (S)-acid was configurationally fully stable up to 45 days in phosphate buffers. Neither clopidogrel nor its carboxylic acid metabolites were subject to enzymatic chiral inversion in isolated rat hepatocyte suspensions. We conclude that the nonenzymatic inversion of clopidogrel accounts for the 4 to 8% of chiral inversion seen in vivo in the rat.     

大鼠口服硫酸氢氯吡格雷的多晶型吸收特点研究

本文采用多种分析检测技术对硫酸氢氯吡格雷的4种晶型物质进行了表征,并采用高效液相色谱(high performance liquid chromatogram,HPLC)技术测定大鼠血浆中硫酸氢氯吡格雷及其代谢产物的含量,研究了大鼠口服硫酸氢氯吡格雷4种不同晶型的吸收特点。结果显示大鼠灌胃给予硫酸氢氯吡格雷后血浆中可以检测到反应吸收过程的代谢产物,硫酸氢氯吡格雷4种晶型的代谢产物曲线下面积有显著性差异。故认为硫酸氢氯吡格雷的不同晶型物质表现出不同的药代动力学特征,提示晶型物质状态不同可能会影响药物的体内作用。     

Impaired liver cytochrome P450 2C11 activity after dual antiplatelet therapy with aspirin and clopidogrel in rats

1. Aspirin (ASA) and clopidogrel (CLP) are used in combination as dual antiplatelet therapy (DAPT) for acute coronary syndrome based on their complementary mechanisms for platelet aggregation inhibition. However, the pharmacokinetics of such drug combination usage has not been thoroughly investigated.

2. In the current study, an LC–MS/MS method was developed to simultaneously determine the plasma concentrations of ASA and its metabolite salicylic acid (SA) with CLP and its metabolites, clopidogrel carboxylic acid (CLPM) and clopidogrel active metabolite derivative (CAMD). The pharmacokinetics of ASA, SA, CLP, CLPM and CAMD in rats receiving two-week DAPT with ASA and CLP were then determined.

3. After two-week DAPT with ASA and CLP in rats, the activities of aspirin esterase and rCyp2c11, enzymes mediating rat metabolism of ASA and CLP, respectively, in prepared rat liver microsomes were measured followed by further determination of rCyp2c11 mRNA expressions. The results demonstrated that DAPT led to minimal impact on aspirin esterase activity but significant decrease in rCyp2c11 activity and mRNA expression.

4. In conclusion, our findings on impairment in rCyp2C11 activity and mRNA expression by DAPT in rats could provide guidance on its safe clinical use with other CYP 2C19 substrates.     

Clopidogrel variability: role of plasma protein binding alterations

Aim

The large inter-individual variability in clopidogrel response is attributed to pharmacokinetics. Although, it has been used since the late 1990s the pharmacokinetic fate of clopidogrel and its metabolites are poorly explained. The variable response to clopidogrel is believed to be multi-factorial, caused both by genetic and non-genetic factors. In this study, we examined whether the inactive metabolite can alter the plasma protein binding of the active metabolite, thus explaining the large inter-individual variability associated with clopidogrel response.

Methods

Female subjects (n = 28) with stable coronary disease who were not taking clopidogrel were recruited. Serial blood samples were collected following 300 mg oral dose of clopidogrel, plasma was isolated and quantified for total and free concentrations of active and inactive metabolites. Inhibition of platelet aggregation was measured using the phosphorylated vasodilator stimulated phosphoprotein (VASP) assay.

Results

A significant correlation was observed between VASP and both free (r = 0.49, P < 0.05) and total (r = 0.49, P < 0.05) concentrations of the active metabolite. Surprisingly, we observed a significant correlation with both free (r = 0.42, P < 0.05) and total (r = 0.67, P < 0.001) concentrations of the inactive metabolite as well. Free fractions of the active metabolite rose with increasing protein binding of the inactive metabolite (P < 0.05).

Conclusions

The above in vivo data suggest that the inactive metabolite displaces the active metabolite from binding sites. Thus, the inactive metabolite might increase the free concentration of the active metabolite leading to enhanced inhibition of platelet aggregation. The plasma protein binding mechanism would offer an additional therapeutic strategy to optimize clopidogrel pharmacotherapy.     

Population pharmacokinetic analysis of clopidogrel in healthy Jordanian subjects with emphasis optimal sampling strategy

Aim: Clopidogrel is metabolized primarily into an inactive carboxyl metabolite (clopidogrel‐IM) or to a lesser extent an active thiol metabolite. A population pharmacokinetic (PK) model was developed using NONMEM® to describe the time course of clopidogrel‐IM in plasma and to design a sparse‐sampling strategy to predict clopidogrel‐IM exposures for use in characterizing anti‐platelet activity.Methods: Serial blood samples from 76 healthy Jordanian subjects administered a single 75 mg oral dose of clopidogrel were collected and assayed for clopidogrel‐IM using reverse phase high performance liquid chromatography. A two‐compartment (2‐CMT) PK model with first‐order absorption and elimination plus an absorption lag‐time was evaluated, as well as a variation of this model designed to mimic enterohepatic recycling (EHC). Optimal PK sampling strategies (OSS) were determined using WinPOPT based upon collection of 3–12 post‐dose samples.Results: A two‐compartment model with EHC provided the best fit and reduced bias in C_max (median prediction error (PE%) of 9.58% versus 12.2%) relative to the basic two‐compartment model, AUC_0‐24 was similar for both models (median PE% = 1.39%). The OSS for fitting the two‐compartment model with EHC required the collection of seven samples (0.25, 1, 2, 4, 5, 6 and 12 h). Reasonably unbiased and precise exposures were obtained when re‐fitting this model to a reduced dataset considering only these sampling times.Conclusions: A two‐compartment model considering EHC best characterized the time course of clopidogrel‐IM in plasma. Use of the suggested OSS will allow for the collection of fewer PK samples when assessing clopidogrel‐IM exposures. Copyright © 2013 John Wiley & Sons, Ltd.     

氯吡格雷单次和多次给药在大鼠体内的药动学特征

目的建立并确证氯吡格雷羧酸代谢物SR26334血浆药物浓度的HPLC检测法,研究氯吡格雷单次和多次大剂量给药后在大鼠体内的药动学特征。方法12只SD大鼠随机分成2组（单次给药组和多次给药组）,单次和多次灌胃给予氯吡格雷30mg·kg-1,多次给药为每天1次,共7d。采用HPLC法测定给药后不同时间点血浆中SR26334浓度,用DAS3．0处理经时血药浓度数据,计算主要药动学参数。结果单次给药和多次给药后SR26334血药浓度均于给药后约1h达峰,pmax分别为（35．57±10．25）mg·L。和（54．28±10．39）mg·L-1;两者g1／2z相近,分别为（6．88±1．54）h和（6．54±1．04）h;AUC0—24h分别为（304．63±63．07）mg·h·L-1和（543．81±43,27）mg·h·L-1;AUC0-∞分别为（334．00±66．24）mg·h·L-1和（594．91±46．84）mg·h·L-1;Vz／F分别为（0．92±0．23）L·kg。和（0．48±0．07）L·kg-1;CLz／F分别为（0．09±0．02）L·h-1·kg-1和（0．05±0．00）L·h-1·kg-1。结论氯吡格雷单次与多次给药后的主要药动学参数AUC0-24h、AUC0-∞、Vz／F、ck／F和pmax差异具有统计学意义（P〈0．01,P〈0．05）,说明多次大剂量给药时其代谢物SR26334在体内有蓄积。     

Comparison of formation of thiolactones and active metabolites of prasugrel and clopidogrel in rats and dogs

1. Prasugrel and clopidogrel are antiplatelet prodrugs that are converted to their respective active metabolites through thiolactone intermediates. Prasugrel is rapidly hydrolysed by esterases to its thiolactone intermediate, while clopidogrel is oxidized by cytochrome P450 (CYP) isoforms to its thiolactone. The conversion of both thiolactones to the active metabolites is CYP mediated. This study compared the efficiency, in vivo, of the formation of prasugrel and clopidogrel thiolactones and their active metabolites.

2. The areas under the plasma concentration versus time curve (AUC) of the thiolactone intermediates in the portal vein plasma after an oral dose of prasugrel (1 mg kg^?1) and clopidogrel (0.77 mg kg^?1) were 15.8 ± 15.9 ng h ml^?1 and 0.113 ± 0.226 ng h ml^?1, respectively, in rats, and 454 ± 104 ng h ml^?1 and 23.3 ± 4.3 ng h ml^?1, respectively, in dogs, indicating efficient hydrolysis of prasugrel and little metabolism of clopidogrel to their thiolactones in the intestine.

3. The relative bioavailability of the active metabolites of prasugrel and clopidogrel calculated by the ratio of active metabolite AUC (prodrug oral administration/active metabolite intravenous administration) were 25% and 7%, respectively, in rats, and 25% and 10%, respectively, in dogs.

4. Single intraduodenal administration of prasugrel showed complete conversion of prasugrel, resulting in high concentrations of the thiolactone and active metabolite of prasugrel in rat portal vein plasma, which demonstrates that these products are generated in the intestine during the absorption process.

5. In conclusion, the extent of in vivo formation of the thiolactone and the active metabolite of prasugrel was greater than for clopidogrel’s thiolactone and active metabolite.