聚氧乙烯醚类表面活性剂对大鼠体内细胞色素P450 3A活性的影响

为研究药用辅料对大鼠体内细胞色素P450 3A(CYP3A)药酶活性的影响， 大鼠分别灌胃生理盐水、 酮康唑(75 mg·kg^-1·d^-1)， 曲拉通X-100(30 mg·kg^-1·d^-1)、 聚氧乙烯蓖麻油(EL35, 150 mg·kg^-1·d^-1)、 聚氧乙烯氢化蓖麻油(RH40, 150 mg·kg^-1·d^-1) 5 d后， 12 h禁食再经十二指肠给予上述试药， 20 min后给予咪哒唑仑作为探针。分别测定咪哒唑仑及其代谢物1′-羟基咪哒唑仑在大鼠体内的血药浓度并计算其药代动力学参数， 比较曲拉通X-100、 EL35和RH40处理组与生理盐水组的药代动力学差异。结果显示， 阳性对照药酮康唑对CYP3A有明显的抑制作用； 而曲拉通X-100、 EL35和RH40使1′-羟基咪哒唑仑与咪哒唑仑的AUC_0-∞比值分别从1.14降至0.90、 1.03和0.64，统计学分析表明曲拉通X-100和EL35对CYP3A没有明显的抑制作用， 而RH40对CYP3A有明显的抑制作用。因此， 在药物制剂研究及临床应用中， RH40有可能影响经细胞色素P450 3A转化的药物代谢及处置， 增加药物的生物利用度， 对药物的临床应用产生显著影响。     

探针药物法评价丁苯酞对大鼠体内CYP3A酶活性的影响

目的研究丁苯酞连续多次灌胃给药对大鼠CYP3A酶活性的影响。方法 40只Wistar大鼠随机分为4组。对照组灌胃给予橄榄油;实验组分为低、中、高3个剂量组,分别灌胃给予丁苯酞40、80、160 mg·kg^-1（以橄榄油溶解）。对照组和实验组均连续灌胃5 d,于第6日尾静脉注射探针药物咪达唑仑（4 mg·kg^-1）后由眼底静脉丛取血,高效液相色谱法测定血药浓度,以DAS 2.1.1药物动力学程序拟合药动学参数,以SPSS18.0软件对组间各参数进行统计分析。结果咪达唑仑在0.06～30μg·mL^-1内线性关系良好（r=0.999 4）;日内、日间RSD〈13%;绝对回收率为80.59%～96.5%。咪达唑仑单用及与低、中、高剂量丁苯酞合用比较,药动学参数AUC0～t、AUC0～∞、t1/2、CLZ、VZ没有显著性差别（P〉0.05）。结论丁苯酞对大鼠体内CYP3A酶活性没有影响。     

大鼠肝细胞色素P4503A活性测定及其孵育条件的优化

目的:测定大鼠肝微粒体中细胞色素P4503A(CYP3A)的活性,并对其体外孵育条件进行优化。方法:采用1’-羟基咪哒唑仑的生成量表示肝中CYP3A的活性,高效液相色谱法测定肝微粒体中1’-羟基咪哒唑仑的浓度,用单因素试验法对其体外孵育条件进行优化,用线性Lineweaver-Burk双倒数作图法研究肝CYP3A酶促动力学。结果:1’-羟基咪哒唑仑在18.20~1 820.00μg.L-1范围内线性关系良好;体外优化的孵育条件为5μmol.L-1咪哒唑仑、0.102mg肝微粒体、孵育15min;肝CYP3A酶促动力学参数Km为1.67μmol.L-1,Vmax为95.15pmol.min-1.mg-1。结论:HPLC法操作简便、灵敏、快速,适用于肝微粒体中1’-羟基咪哒唑仑的浓度测定,肝CYP3A孵育条件及其酶促动力学研究为研究经CYP3A代谢的药物相互作用及其他物质对CYP3A酶的影响提供理论依据。     

高效液相色谱法测定大鼠肝微粒体CYP3A酶的活性

目的 以咪达唑仑为探针药用HPLC法测定大鼠肝微粒体CYP3A酶活性.方法 用ZORBAX SB-C18色谱柱分离;流动相为乙腈-水-0.1％三氟乙酸;流速为1 mL· min-1;柱温40℃;检测波长为230 nm.肝微粒体加入咪达唑仑孵育5 min后,用乙腈终止反应,加入内标溶液50 μL,混匀后离心10 min,取上清进行HPLC分析;计算Km和Vmax.结果 1-羟基咪达唑仑浓度在0.06～3.00 mg· L-1内线性关系良好;日内、日间精密度均＜10％,回收率＞75％.咪达唑仑羟化反应的Km =7.32μmol· L-,Vmax=0.59 nmol·min-1·mg-1 pro.结论 本方法稳定可靠,能准确反映CYP3A酶的活性.     

马来酸咪达唑仑片在汉族健康人体内的药动学研究

目的:研究马来酸咪达唑仑片在汉族健康人体内的药动学。方法:10名汉族健康受试者口服马来酸咪达唑仑片15mg后,用高效液相色谱法测定咪达唑仑血药浓度,用DAS2.0药动学软件拟合药动学参数。结果:受试者单剂量口服马来酸咪达唑仑片后的主要药动学参数分别为Cma(x103.11±26.37)ng·mL-1、tma(x1.52±0.75)h、t1/(22.96±0.77)h、Vz/F(170.08±50.97)L、CL/F(41.05±12.33)L·h-1、AUC0～1(2368.80±103.37)ng·h·mL-1、AUC0～∞(397.29±124.06)ng·h·mL-1。部分受试者的药-时曲线存在双峰现象。结论:咪达唑仑片的药动学参数个体差异较大,临床应用时应注意个体化给药。     

咪达唑仑临床药动学参数的研究

目的:研究咪达唑仑的临床药动学参数。方法:选择14例咪达唑仑复合瑞芬太尼、异氟醚全身麻醉手术患者,以恒速20μg·kg-1.min-1静脉泵注咪达唑仑20min,于给药前,给药后1、3、5、7、10、15、20min,停药后5、15、30、45min及1、2、4、6、12、18、24h分别抽取桡动脉血3mL,应用高效液相色谱法检测血浆中咪达唑仑的浓度,DAS2.1.1软件计算药动学参数。结果:咪达唑仑给药后药-时曲线可用开放性三房室模型描述,其中权重系数为1,t1/2α=9.5842min,t1/2β=85.3677min,t1/2γ=339.7365min,中央室分布容积(V1)=0.1821L.kg-1,CL=119.4344mL.h-1.kg-1,K10=0.0458min-1,K12=0.0863min-1,K21=0.0175min-1,K13=0.0133min-1,K31=0.0024min-1。结论:t1/2α、t1/2β、t1/2γ、CL与国外文献报道一致,但V1偏小,用药易于达到平衡,而清除速率较快,可能更符合中国人的药动学特征。     

五味子甲素对CYP3A活性的影响及其体内外相关性研究

目的:通过"探针"法探讨五味子甲素体内、外对大鼠肝微粒体CYP3A活性的影响及其相关性。方法:选取咪达唑仑作为CYP3A探针,用高效液相色谱法测定五味子甲素体外孵育给药和体内灌胃给药后大鼠肝微粒体酶CYP3A活性,通过药动学参数K_m确定其体内、外作用的相关性。结果:体外试验结果表明,五味子甲素非竞争性抑制咪达唑仑的代谢,其K_i为5.5μmol·L^-1,体内试验亦证实了五味子甲素能显著抑制肝微粒体CYP3A酶活性（P<0.01）并呈剂量依赖性,其体内给药的K_i值为30.67 mg·kg^-1。体内外K_m值十分接近。结论:五味子甲素在体内和体外均可非竞争性抑制大鼠肝微粒体酶CYP3A活性,其对CYP3A影响的体内、体外结果具有良好的相关性。     

候选新药对大鼠肝细胞色素P4503A4影响的研究

目的研究候选新药(HSH)对大鼠肝细胞色素P4503A4是否有抑制或诱导作用,以及这种作用是否具有性别差异。方法取大鼠雌雄各半,随机分为4个组:雄性对照组(Ⅰ)、雄性给药组(Ⅱ)、雌性对照组(Ⅲ)、雌性给药组(Ⅳ),均采用钙离子沉淀法制备肝微粒体。在各组肝微粒体中同时给予一定剂量的探针药物及目标药物,进行孵育,于不同时间点取样,测定该探针药物的剩余浓度并计算其体外半衰期。结果HSH对肝细胞色素P4503A4无影响。结论就大鼠而言,药物对肝细胞色素P4503A4无影响,HSH在同各种与CYP3A4代谢有关的药物合用时,相对安全。     

候选新药对大鼠肝细胞色素P4503A4影响的研究

目的研究候选新药(HSH)对大鼠肝细胞色素P4503A4是否有抑制或诱导作用,以及这种作用是否具有性别差异。方法取大鼠雌雄各半,随机分为4个组:雄性对照组(Ⅰ)、雄性给药组(Ⅱ)、雌性对照组(Ⅲ)、雌性给药组(Ⅳ),均采用钙离子沉淀法制备肝微粒体。在各组肝微粒体中同时给予一定剂量的探针药物及目标药物,进行孵育,于不同时间点取样,测定该探针药物的剩余浓度并计算其体外半衰期。结果HSH对肝细胞色素P4503A4无影响。结论就大鼠而言,药物对肝细胞色素P4503A4无影响,HSH在同各种与CYP3A4代谢有关的药物合用时,相对安全。     

咪达唑仑片在中国回族、朝鲜族和汉族受试者体内的药动学比较

目的比较研究中国回族、朝鲜族和汉族健康志愿者单剂量口服咪达唑仑片的药动学。方法回族和汉族志愿者各10名,朝鲜族9名,单剂量口服15mg咪达唑仑片后,高效液相色谱法测定咪达唑仑的血浆浓度,用DAS2.0药动学软件拟合主要药动学参数,并采用单因素方差分析和KrusKal-Wallis秩合检验对药动学参数进行比较。结果咪达唑仑片的药动学参数Cmax、MRT0-12h和Tmax等在回族、朝鲜族和汉族3个民族间的差异有统计学意义(P<0.05),在同一民族和不同民族的个体间差异都非常大。超过半数男、女受试者的药-时曲线都存在双峰现象。结论咪达唑仑片在回族、朝鲜族和汉族健康受试者间的药动学存在民族差异和个体差异,临床应用时应该注意调整剂量。     

CYP3A4酶介导的人类药物代谢性别差异

药代动力学的性别差异是临床上药物疗效的重要影响因素。引起药代动力学性别差异的比较重要的分子因素包括药物代谢酶和药物转运体等。CYP3A4是人体含量最丰富的酶,具有广泛的代谢底物。大部分体内、外研究表明CYP3A4底物的代谢具有明显的性别差异,女性体内的代谢快于男性。该文系统综述人肝脏CYP3A4酶介导的药物代谢性别差异的研究进展。     

以睾酮为探针测定大鼠CYP3A酶活性的实验研究

目的建立一种简便、快速、可靠的以睾酮作为探针药物,评价大鼠CYP3A酶活性的高效液相色谱检测方法。方法色谱柱为HypersilBDSC18柱(4.6mm×150mm,5μm),柱温为25℃,检测波长为254nm,内标为氢化可的松,流动相为甲醇-10mmol·L-1Na2HPO4水溶液(pH8.25)(55∶45),流速为1mL·min-1。睾酮以大鼠肝微粒体温孵后,用乙酸乙酯萃取,离心取上清液挥干后用甲醇-水(1∶1)复溶进样分析。结果睾酮和氢化可的松的保留时间分别为17.74min和6.05min;睾酮的孵育产物6β-羟基睾酮的保留时间为4.72min,回归方程为Y=0.0756X-0.0214(r=0.9980),线性范围为0.3125～20μg·mL-1,检测限下限质量浓度为(0.078±0.016)μg·mL-1(S/N≥3),提取回收率为79.3%～95.1%,方法回收率为98.0%～104.0%,低、中、高三个浓度日内、日间RSD均小于10.4%;温孵体系中其他内源性物质不干扰测定。结论所建立的HPLC稳定、高效,适合睾酮及其代谢产物6β-羟基睾酮的测定,可应用于药物对大鼠CYP3A酶活性的评价。     

金雀异黄酮在体内对CYP3A活性的影响

目的:阐明金雀异黄酮在体内对细胞色素氧化酶P-4503A(CYP3A)活性的影响。方法:本试验采用双周期交叉临床试验。临床试验按照两阶段交叉方案进行。第一阶段随机分成的2组受试者随机给予金雀异黄酮片或安慰剂处理14 d,第15天给所有受试者米哒唑仑探针药,经过14 d洗脱期后交叉重复试验,分别以0~36 h血浆中米哒唑仑的血浆曲线下面积、半衰期作为CYP3A的活性指标。HPLC测定其活性。服药后0~36 h血中咪达唑仑以及1’-羟基咪达唑仑用HPLC-MS/MS方法测定。结果:经金雀异黄酮处理后,咪达唑仑AUC0-36 h明显降低[(144±55)ng.mL-1.hvs(126±40)ng.mL-1.h,P<0.05],AUC0-∞显著降低[(209±57)vs(181±43)ng.mL-1.h,P<0.05],Cmax显著降低[(49±20)vs(36±14),P<0.05]。结论:金雀异黄酮对体内CYP3A酶活性具有显著的诱导作用,应当关注经CYP3A代谢的药物与金雀异黄酮合用时可能发生的潜在的药物相互作用。     

淫羊藿苷对不同月龄大鼠肝微粒体细胞色素P450的影响

目的 揭示淫羊藿苷(Ica)对大鼠肝微粒体细胞色素P450的含量及部分亚型的影响,并比较月龄的差异.方法 ig给予6月龄和18月龄的♂SD大鼠Ica( 60 mg· kg -1),4周后取肝脏,用钙沉淀法提取肝微粒体,BCA法测定微粒体蛋白浓度;用一氧化碳还原差示光谱法测定CYP450的含量;用ELISA法测定CYP1 A1、CYPb5的含量;用比色法测定苯胺羟化酶(反映CYP2E1活性)和红霉素-N-脱甲基酶(反映CYP3A活性)的活性;用real - time RT - PCR检测CYP1 A1、CYP2A3、CYP2E1、CYP3A1、CYP3A2和CYP4B1 mRNA的表达.结果 60 mg· kg-1 Ica明显增加了CYP450的总酶和CYP1 A1的含量、CYP3A的活性及CYP1 A1、CYP3A1、CYP3A2 mRNA的表达,降低了CYP2E1的活性及其mRNA的表达;但Ica对上述各指标的诱导或抑制作用在大鼠月龄方面差异不明显;Ica对CYPb5的含量及CYP2A3、CYP4B1 mRNA的表达未见明显影响.结论 Ica对大鼠肝微粒体CYP450总酶、CYPI A1和CYP3A具有诱导作用,对CYP2E1具有抑制作用,该作用未见明显月龄差异.     

In vitro study on the effect of peucedanol on the activity of cytochrome P450 enzymes

ContextPeucedanol is a major extract of Peucedanum japonicum Thunb. (Apiaceae) roots, which is a commonly used herb in paediatrics. Its interaction with cytochrome P450 enzymes (CYP450s) would lead to adverse effects or even failure of therapy.ObjectiveThe interaction between peucedanol and CYP450s was investigated.Materials and methodsPeucedanol (0, 2.5, 5, 10, 25, 50, and 100 μM) was incubated with eight human liver CYP isoforms (CYP1A2, 2A6, 3A4, 2C8, 2C9, 2C19, 2D6, and 2E1), in pooled human liver microsomes (HLMs) for 30 min with specific inhibitors as positive controls and untreated HLMs as negative controls. The enzyme kinetics and time-dependent study (0, 5, 10, 15, and 30 min) were performed to obtain corresponding parameters in vitro.ResultsPeucedanol significantly inhibited the activity of CYP1A2, 2D6, and 3A4 in a dose-dependent manner with IC₅₀ values of 6.03, 13.57, and 7.58 μM, respectively. Peucedanol served as a non-competitive inhibitor of CYP3A4 with a K_i value of 4.07 μM and a competitive inhibitor of CYP1A2 and 2D6 with a K_i values of 3.39 and 6.77 μM, respectively. Moreover, the inhibition of CYP3A4 was time-dependent with the K_i/K_inact value of 5.44/0.046 min/μM.Discussion and conclusionsIn vitro inhibitory effect of peucedanol on the activity of CYP1A2, 2A6, and 3A4 was reported in this study. As these CYPs are involved in the metabolism of various drugs, these results implied potential drug-drug interactions between peucedanol and drugs metabolized by CYP1A2, 2D6, and 3A4, which needs further in vivo validation.     

Time-dependent changes in hepatic and intestinal induction of cytochrome P450 3A after administration of dexamethasone to rats

Abstract

1.?We investigated the effects of the dose of and the number of times an inducer was administered and the duration of induction of hepatic and intestinal cytochrome P450 3A (CYP3A) in rats using dexamethasone 21-phosphate (DEX-P) and midazolam (MDZ) as an inducer and a substrate to CYP3A, respectively.

2.?The number of times DEX-P was administered was not a significant factor in the induction of either hepatic or intestinal CYP3A; however, administration of DEX-P multiple times markedly decreased the bioavailability of DEX-P by self-induction of CYP3A.

3.?CYP3A induction in the liver increased depending on the dose of DEX-P, whereas that in intestine showed a mild increase, but the induction level was almost constant regardless of the dose of DEX-P.

4.?Administration of a single dose of DEX-P showed a temporal increase in CYP3A activity in both tissues and the induction ratios reached maximum values at 12?h after DEX-P administration. On the other hand, a mild increase of CYP3A activity, which lasted for at least 48?h, was observed in both tissues after administration of multiple doses.

5.?Some physiological compounds such as cytokines might be involved in decreasing the CYP3A activity to maintain homeostasis of the body.     

Effects of cytochrome P450 3A4 and non-genetic factors on initial voriconazole serum trough concentrations in hematological patients with different cytochrome P450 2C19 genotypes

1.?Polymorphisms of cytochrome P450 2C19 (CYP2C19) is an important factor contributing to variability of voriconazole pharmacokinetics. Polymorphisms of CYP3A4, CYP3A5, CYP2C9 and non-genetic factors such as age, gender, body mass index (BMI), transaminase levels, concomitant medications might also affect voriconazole initial steady serum trough concentration (VIC_min) in haematological patients, but the effects were not clear.

2.?Eighteen single-nucleotide polymorphisms in CYP2C19, CYP3A4, CYP3A5, CYP2C9 were genotyped. Patients were stratified into two groups according to CYP2C19 genotype. Group 1 were patients with CYP2C19*2 or CYP2C19*3, and Group 2 were homozygous extensive metabolizers. The effects were studied in different groups. VIC_min was adjusted on daily dose (VIC_min/D) for overcoming effect of dose.

3.?A total of 106 blood samples from 86 patients were included. In final optimal scaling regression models, polymorphisms of rs4646437 (CYP3A4), age, BMI was identified to be factors of VIC_min/D in Group 1 (R^2?=^?.255, p?<?.001). Only age was confirmed as a factor of VIC_min/D in Group 2 (R^2?=^?0.144, p?=?.021).

4.?Besides polymorphisms of CYP2C19, in individualized medication of voriconazole in haematological patients, polymorphisms of CYP3A4, and non-genetic factors as BMI, age should also be taken into account, especially for individuals with CYP2C19*2 or CYP2C19*3.     

Effect of genistein on the activities of cytochrome P450 3A and P-glycoprotein in Chinese healthy participants

1. To determine the effect of genistein on cytochrome P450 3A (CYP3A) and P-glycoprotein (P-gp) function using the probe substrates midazolam and talinolol, respectively. Eighteen healthy adult male participants were enrolled in a two-phase randomized crossover design. In each phase, the participants received placebo or genistein for 14 days. On the 15th day, midazolam and talinolol were administered and blood samples were obtained. Midazolam and talinolol pharmacokinetic parameter values were calculated and compared before and after genistein administration.

2. Co-administration of genistein decreased the area under the concentration–time curve from 0 to 36?h (AUC 0-36) (143.65?±?55.40?ng h/mL versus 126.10?±?40.14?ng h/mL, p?<?0.05), and the area under the concentration–time curve from zero to infinity (AUC 0-∞) (209.18?±?56.61?ng h/mL versus 180.59?±?43.03?ng h/mL, p?<?0.05), and also maximum concentration (Cmax) of midazolam (48.86?±?20.21?ng/mL versus 36.25?±?14.35?ng/mL p?<?0.05). Similarly, AUC 0-36 (2490.282?±?668.79?ng h/mL versus 2114.46?±?861.11?ng h/mL, p?<?0.05), AUC 0-∞ (2980.45?±?921.09?ng h/mL versus 2626.92?±?1003.78?ng h/mL, p?<?0.05) and Cmax of talinolol (326.58?±?197.67?ng/mL versus 293.42?±?127.19?ng/mL, p?<?0.05) were reduced by genistein co-administration. The oral clearance of midazolam (1.68?±?0.85 h-1 versus 3.98?±?0.59 h-1, p?<?0.05) and talinolol (3.34?±?1.24 h-1 versus 3.79?±?1.55 h-1, p<0.05) were increased by genistien significantly.

3. Administration of genistein can result in a modest induction of CYP3A and possibly P-gp activity in healthy volunteers.

     

Thiomers: Inhibition of cytochrome P450 activity

The aim of the present study was to investigate the potential of different thiolated polymers (thiomers) on the catalytic activity of CYP450s on one hand and to explore new inhibitors for CYP activity on the other hand. Several thiolated polymers including poly(acrylic acid)-cysteine (PAA-cysteine), chitosan-thioglycolic acid (chitosan-TGA), and thiolated PEG-g-PEI copolymer along with brij® 35, myrj® 52 and the well-established CYPP450 inhibitor verapamil were screened for their CYP3A4 and CYP2A6 inhibitory activity, and their IC₅₀ values were determined. Both enzyme inhibition assays were performed in 96-well microtiter plates. 7-Benzyloxy-4-(trifluoromethyl)-coumarin (BFC) and 7-hydroxycoumarin (7-HC) were used as fluorescent substrates in order to determine CYP3A4 and CYP2A6 catalytic activity, respectively. All investigated compounds inhibited CYP3A4 as well as CYP2A6 activity. All tested (thiolated) polymers were found to be more potent inhibitors of CYP3A4 than of CYP2A6 catalytic activity. Apart from verapamil that is a known CYP3A4 inhibitor, brij® 35 and myrj® 52 were explored as potent inhibitors of CYP3A4 and CYP2A6 catalytic activity. Among the tested polymers, the rank order for CYP3A4 inhibition was PAA-cysteine (100 kDa) > brij® 35 > thiolated PEG-g-PEI copolymer (16 kDa) > myrj® 52 > PAA (100 kDa) > PAA-cysteine (450 kDa) > verapamil > PAA (450 kDa) > chitosan-TGA (150 kDa) > chitosan (150 kDa). On the other hand, the rank order of CYP2A6 inhibition was brij® 35 > PAA-cysteine (100 kDa) > chitosan-TGA (150 kDa) > PAA (100 kDa) > thiolated PEG-g-PEI copolymer (16 kDa) > PAA-cysteine (450 kDa) > chitosan (150 kDa) > verapamil > PAA (450 kDa) > myrj® 52. Thus, this study suggests that (thiolated) polymers display a promising potential to inhibit cytochrome P450s activity and might turn out to be potentially valuable tools for improving the oral bioavailability of actively secreted compounds by avoiding intestinal metabolism.     

Effect of classic and atypical neuroleptics on cytochrome P450 3A (CYP3A) in rat liver

BackgroundCytochrome P450 3A (CYP3A) subfamily is involved in the metabolism of xenobiotics (e.g., drugs) and endogenous substances (e.g., steroids). The aim of the present study was to investigate the influence of classic and atypical neuroleptics on the level and activity of CYP3A in rat liver, measured as a rate of testosterone 2β- and 6β-hydroxylation.MethodsThe reactions were studied in control liver microsomes in the presence of neuroleptics, as well as in the microsomes of rats treated intraperitoneally (ip) with pharmacological doses of the drugs (promazine and thioridazine 10 mg/kg; chlorpromazine 3 mg/kg; haloperidol 0.3 mg/kg; risperidone 0.1 mg/kg; sertindole 0.05 mg/kg) for one day or two weeks (twice a day), in the absence of the neuroleptics in vitro.ResultsThe investigated neuroleptics added in vitro to control liver microsomes produced a moderate or week inhibitory effects on CYP3A activity. After one-day exposure of rats to neuroleptics, only chlorpromazine significantly increased the activity of CYP3A. Chronic treatment of rats with thioridazine diminished the protein level and activity of CYP3A, while risperidone induced this enzyme.ConclusionThe observed changes in the CYP3A expression after prolonged exposition to neuroleptics suggest their influence on the enzyme regulation.