甲硝唑对兰索拉唑在大鼠体内药动学的影响

目的:研究甲硝唑在大鼠体内对兰索拉唑药动学特征的影响。方法:通过对兰索拉唑及细胞色素P450酶2C19(CYP2C19)代谢产物5-羟基兰索拉唑和细胞色素P450酶3A4(CYP3A4)代谢产物兰索拉唑砜的血药浓度的测定,计算大鼠体内药动学参数,以甲硝唑联合兰索拉唑用药组与兰索拉唑单独用药组的AUC0-4h比值为指标,研究甲硝唑对大鼠体内兰索拉唑代谢的影响。结果:联用甲硝唑后,兰索拉唑的AUC0-4h降低为单独使用兰索拉唑组的(0.20±0.06)倍(P<0.05)。甲硝唑显著增加5-羟基兰索拉唑与兰索拉唑AUC0-4h的比值,从(0.24±0.08)增至(0.39±0.19)(P<0.05)。结论:甲硝唑在大鼠体内对兰索拉唑CYP3A4主导的磺化代谢抑制作用不明显,对CYP2C19主导的羟化代谢途径可能有诱导作用。     

Metabolic capabilities of cytochrome P450 enzymes in Chinese liver microsomes compared with those in Caucasian liver microsomes

AIM

The most common causes of variability in drug response include differences in drug metabolism, especially when the hepatic cytochrome P450 (CYP) enzymes are involved. The current study was conducted to assess the differences in CYP activities in human liver microsomes (HLM) of Chinese or Caucasian origin.

METHODS

The metabolic capabilities of CYP enzymes in 30 Chinese liver microsomal samples were compared with those of 30 Caucasian samples utilizing enzyme kinetics. Phenacetin O-deethylation, coumarin 7-hydroxylation, bupropion hydroxylation, amodiaquine N-desethylation, diclofenac 4′-hydroxylation (S)-mephenytoin 4′-hydroxylation, dextromethorphan O-demethylation, chlorzoxazone 6-hydroxylation and midazolam 1′-hydroxylation/testosterone 6β-hydroxylation were used as probes for activities of CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A, respectively. Mann-Whitney U test was used to assess the differences.

RESULTS

The samples of the two ethnic groups were not significantly different in cytochrome-b₅ concentrations but were significantly different in total CYP concentrations and NADPH-P450 reductase activity (P < 0.05). Significant ethnic differences in intrinsic clearance were observed for CYP1A2, CYP2C9, CYP2C19 and CYP2E1; the median values of the Chinese group were 54, 58, 26, and 35% of the corresponding values of the Caucasian group, respectively. These differences were associated with differences in Michaelis constant or maximum velocity. Despite negligible difference in intrinsic clearance, the Michaelis constant of CYP2B6 appeared to have a significant ethnic difference. No ethnic difference was observed for CYP2A6, CYP2C8, CYP2D6 and CYP3A.

CONCLUSIONS

These data extend our knowledge on the ethnic differences in CYP enzymes and will have implications for drug discovery and drug therapy for patients from different ethnic origins.     

Characterization of triptolide hydroxylation by cytochrome P450 in human and rat liver microsomes

Triptolide, the primary active component of a traditional Chinese medicine Tripterygium wilfordii Hook F, has a wide range of pharmacological activities. In the present study, the metabolism of triptolide by cytochrome P450s was investigated in human and rat liver microsomes. Triptolide was converted to four metabolites (M-1, M-2, M-3, and M-4) in rat liver microsomes and three (M-2, M-3, and M-4) in human liver microsomes. All the products were identified as mono-hydroxylated triptolides by liquid chromatography-mass spectrometry (LC-MS). The studies with chemical selective inhibitors, complementary DNA-expressed human cytochrome P450s, correlation analysis, and enzyme kinetics were also conducted. The results demonstrate that CYP3A4 and CYP2C19 could be involved in the metabolism of triptolide in human liver, and that CYP3A4 was the primary isoform responsible for its hydroxylation.     

双环醇对肝脏部分切除大鼠CYP450酶活性和表达的影响(英文)

本研究考察双环醇对肝脏部分切除(PH)后大鼠肝脏微粒体细胞色素P450(CYP)活性、基因和蛋白表达的影响及相关机制。大鼠PH前灌胃给予双环醇(300 mg.kg-1)3次,PH后处死大鼠,取其血清和肝组织进行检测,依次测定血清谷丙转氨酶(ALT)、肝微粒体丙二醛(MDA)和肝脏总CYP含量、4种CYP同工酶活性、基因和蛋白表达。结果显示,双环醇可显著抑制PH大鼠血清ALT和肝微粒体MDA的升高,抑制肝脏总CYP含量的减少,抑制CYP2C6、2C11活性和mRNA表达的下降,明显抑制CYP3A1/2活性的下降,并上调CYP3A1和2E1的mRNA和蛋白表达。结果表明,双环醇对PH大鼠肝脏CYP450酶及部分同工酶活性和表达的改变有明显改善作用,其作用机制可能与其抗氧化作用和酶诱导作用密切相关。     

注射用益气复脉(冻干)对人肝微粒体CYP450各亚型酶活性的影响

目的 研究注射用益气复脉（冻干,YQFM）对人肝微粒体的细胞色素P450亚型酶CYP1A2、CYP2B6、CYP2C8、CYP2C9、CYP2C19、CYP2D6和CYP3A4活性的影响。方法 差速离心法制备人肝微粒体,体外人肝微粒体、YQFM （6.5、32.5、65.0、325.0、650.0、3 250.0和6 500.0 μg/mL）和7种底物探针在还原型辅酶β-NADPH的作用下,37℃水浴孵育30 min,同时设置阴性对照（空白缓冲液）和阳性对照（各亚酶的选择性抑制剂）组;应用液相色谱-串联质谱（LC-MS/MS）法测定探针底物的代谢产物生成量,酶活性以相对阴性对照的百分比表示。结果 与阴性对照组比较,32.5、65.0、325.0、650.0、3 250.0浓度的YQFM对CYP2B6、CYP2C8、CYP2C9、CYP2C19、CYP2D6和CYP3A4活性均不发挥抑制作用;半数抑制浓度（IC₅₀）均大于6 500 μg/mL。结论 YQFM在临床使用过程中发生药物相互作用的概率较小。     

氟西汀的药代动力学及其与CYP450酶的作用

氟西汀是近年来开发的一种新型 5 羟色胺重摄取抑制剂 ,它通过选择性抑制突触间 5 羟色胺 (5 HT)的重摄取和代谢 ,增加突触间 5 HT的传递而发挥作用。氟西汀由细胞色素P45 0 (CYP45 0 )酶进行氧化代谢 ,现已证明CYP2C9,CYP2C19和CYP2D6是介导氟西汀N 去甲基代谢的主要CYP45 0同工酶。由于氟西汀及代谢产物去甲氟西汀分别为CYP2D6、CYP3A4、CYP2C19和CYP2C9的抑制剂 ,因此它可与经这些CYP同工酶催化代谢的药物产生明显的相互作用 ;从而导致不同个体间的药代动力学差异和疗效差异。     

混合探针底物法同时预测细胞色素P450酶5种亚型的抑制作用

本研究建立了混合探针底物法同时预测细胞色素P450(cytochrome P-450，CYP450)酶5种亚型的抑制作用。将CYP450酶5种亚型的特异性探针底物非那西丁(CYP1A2)、右美沙芬(CYP2D6)、甲苯磺丁脲(CYP2C9)、奥美拉唑(CYP2C19)及咪达唑仑(CYP3A4)同时与人肝微粒体在体外进行孵化反应，采用液相色谱-串联质谱分析方法同时测定5个特异性底物及其生成的对应的5种代谢产物(对乙酰氨基酚、右啡烷、4-羟基甲苯磺丁脲、5-羟基奥美拉唑和1′-羟基咪达唑仑)。并选择5种细胞色素P450酶的特异性抑制剂α-萘黄酮(CYP1A2)、奎尼丁(CYP2D6)、磺胺苯吡唑(CYP2C9)、氟康唑(CYP2C19)和酮康唑(CYP3A4)加入到其所对应酶的单个探针底物及混合探针底物的反应体系中，测定生成的代谢物，计算相应IC₅₀值，对方法进行验证。5种特异性的抑制剂与混合探针底物反应后所得的IC₅₀值和与单个探针底物反应后所得的IC₅₀值具有很好的一致性且与文献报道的基本一致。本研究建立的混合探针底物法可以用于快速高通量地同时预测化合物对CYP450酶5种亚型活性的抑制作用。     

Metabolism of myclobutanil and triadimefon by human and rat cytochrome P450 enzymes and liver microsomes

Metabolism of two triazole-containing antifungal azoles was studied using expressed human and rat cytochrome P450s (CYP) and liver microsomes. Substrate depletion methods were used due to the complex array of metabolites produced from myclobutanil and triadimefon. Myclobutanil was metabolized more rapidly than triadimefon, which is consistent with metabolism of the n-butyl side-chain in the former and the t-butyl group in the latter compound. Human and rat CYP2C and CYP3A enzymes were the most active. Metabolism was similar in microsomes prepared from livers of control and low-dose rats. High-dose (115?mg?kg^?1?day^?1 of triadimefon or 150?mg?kg^?1?day^?1 of myclobutanil) rats showed increased liver weight, induction of total CYP, and increased metabolism of the two triazoles, though the apparent K_m appeared unchanged relative to the control. These data identify CYP enzymes important for the metabolization of these two triazoles. Estimated hepatic clearances suggest that CYP induction may have limited impact in vivo.     

Chemical inhibitors of CYP450 enzymes in liver microsomes: combining selectivity and unbound fractions to guide selection of appropriate concentration in phenotyping assays

Abstract

1.?Chemical inhibition is the widely used method in reaction phenotyping assays for estimation of specific enzyme contribution to a given metabolic pathway. The results from phenotyping assays depend on the selectivity of chemical inhibitor and the concentration of inhibitor used in the incubation.

2.?The higher protein concentrations used in the in vitro phenotyping assays will impact the inhibitory potency of chemical inhibitors. The objective of the study is to evaluate comprehensively the selectivity of chemical inhibitors and to guide in selecting appropriate concentration of the chemical inhibitors to be used in the phenotyping assays based on unbound fractions.

3.?Selectivity of chemical inhibitors against nine major CYP450 isoforms was determined in liver microsomes using standard probe substrates. The unbound fractions of the selective inhibitors were determined in human liver microsomes using high-throughput equilibrium dialysis. Combining unbound inhibitor concentrations that are required to inhibit the CYP450 activities by 90% and unbound fractions of the chemical inhibitors in liver microsomes appropriate total concentrations of the inhibitors to be used in the phenotyping assays were reported.

4.?The findings suggest that non-specific binding of the chemical inhibitors need to be taken into account while selecting concentrations for phenotyping assays.     

脉络宁注射液酚酸类成分在大鼠体内的药代动力学研究

目的：研究脉络宁注射液中酚酸类成分在大鼠体内药代动力学规律。方法：大鼠尾静脉注射给予脉络宁注射液10 mL/kg,给药前及给药后不同时间采集血样或尿样,LC-MS法测定酚酸类成分浓度,血药浓度-时间数据和尿药排泄量-时间数据用DAS软件进行动力学分析。结果：绿原酸（CGA）、1 ,5-二咖啡酰奎宁酸（1 ,5-DCQA）、3 ,4-二咖啡酰奎宁酸（3 ,4-DCQA）、3 ,5-二咖啡酰奎宁酸（3 ,5-DCQA）和咖啡酸（CA）血药浓度迅速下降达峰,消除t1/2分别为0 .649、0 .334、0 .479、0 .486、0 .330 h,AUC0 -∞分别是（22 .522±2 .716）（CGA）、（0 .353±0 .062）（1 ,5-DCQA）、（3 .620±1 .246）（3 ,4-DCQA）、（5 .287±1 .627）（3 ,5-DCQA）和（2 .257±0 .360）（CA） mg.L-1.h。CGA、1 ,5-DCQA、3 ,4-DCQA、3 ,5-DCQA和CA在尿中0 -24 h累积排泄率分别为（122 .22±26 .49） %、（3 .30±1 .26） %、（0 .24±0 .11） %、（1 .93±0 .77） %和（18 .61±4 .99） %,尿排泄t1/2在1 -4 h。结论：脉络宁注射液中酚酸类成分在体内迅速被排泄出体外,CGA、1 ,5-DCQA、3 ,4-DCQA、3 ,5-DCQA和CA均可从尿排泄,但其中1 ,5-DCQA、3 ,4-DCQA、3 ,5-DC-QA和CA尿药排泄量较少,存在其他代谢途径。     

银杏内酯B注射液在健康人体的药代动力学

目的研究中国健康志愿者单次静滴银杏内酯B(抗脑梗塞药)的药代动力学。方法26名健康志愿者随机分成3组,分别单次静滴银杏内酯B注射液20、40、60mg。用LC-MS-MS法测定给药后不同时间点血浆中的银杏内酯B浓度,并用DASver2.0软件计算其药代动力学参数。结果血药浓度-时间曲线符合二房室模型,药代动力学参数中,3组的t1/2z无显著性差异,并与给药剂量无关;3组的AUC0-t随给药剂量的加大而增加;3组的AUC/dose,c/dose间差异具有统计学意义。结论在20～60mg内,银杏内酯B注射液的体内过程,基本符合线性动力学特征。     

Cocktail法研究CYP450酶活性影响因素的探讨

细胞色素P450酶(cytochrome P450, CYP450)是药物代谢的重要酶系,研究CYP450对阐明药物代谢通路、相互作用、代谢多态性、指导临床合理用药等方面具有重要意义.混合探针底物法(Cocktail法)在研究CYP450亚型酶活性应用广泛,具有高效、准确、灵敏、高通量的特点.但CYP450亚型酶存在种属差异、性别差异、探针药物的特异性等方面的问题.查阅国内外相关文献,探讨Cocktail法研究CYP450酶活性的影响因素.     

Effects of notoginsenoside R1 on CYP1A2, CYP2C11, CYP2D1, and CYP3A1/2 activities in rats by cocktail probe drugs

Context: Notoginsenoside R1 (NGR1) is the main component with cardiovascular activity in Panax notoginseng (Burk.) F. H. Chen, an herbal medicine that is widely used to enhance blood circulation and dissipate blood stasis.

Objective: The objective of this study is to investigate NGR1's effects on CYP1A2, CYP2C11, CYP2D1, and CYP3A1/2 activities in rats in vivo through the use of the Cytochrome P450 (CYP450) probe drugs.

Materials and methods: After pretreatment with NGR1 or physiological saline, the rats were administered intraperitoneally with a mixture solution of cocktail probe drugs containing caffeine (10?mg/kg), tolbutamide (15?mg/kg), metoprolol (20?mg/kg), and dapsone (10?mg/kg). The bloods were then collected at a set of time-points for the ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) analysis.

Results: NGR1 was shown to exhibit an inhibitory effect on CYP1A2 by increased caffeine C_max (43.13%, p?<?0.01) and AUC_0???∞ (40.57%, p?<?0.01), and decreased CL/F (62.16%, p?<?0.01) in the NGR1-treated group compared with those of the control group, but no significant changes in pharmacokinetic parameters of tolbutamide, metoprolol, and dapsone were observed between the two groups, indicating that NGR1 had no effects on rat CYP2C11, CYP2D1, and CYP3A1/2.

Discussion and conclusion: When NGR1 is co-administered with drugs that are metabolized by CYP1A2, the pertinent potential herb–drug interactions should be monitored.     

克拉霉素对兰索拉唑及其代谢产物在大鼠体内药动学特征的影响

目的研究克拉霉素对兰索拉唑及其代谢产物5-羟基兰索拉唑和兰索拉唑砜药动学特征的影响。方法 24只大鼠随机分为4组,分别十二指肠给予兰索拉唑(8 mg·kg^-1)+生理盐水、兰索拉唑(8 mg·kg^-1)+酮康唑(5 mg·kg^-1)、兰索拉唑(8 mg·kg^-1)+反苯环丙胺(5 mg·kg^-1)、兰索拉唑(8 mg·kg^-1)+克拉霉素(8 mg·kg^-1)。于给药后不同时间点采集血样,用LC-MS/MS法测定药物浓度。通过对兰索拉唑及5-羟基兰索拉唑和兰索拉唑砜血药浓度的测定,计算大鼠体内药动学参数。以5-羟基兰索拉唑、兰索拉唑砜与兰索拉唑AUC_0→4h的比值分别作为原药经CYP2C19和CYP3A4代谢程度的指标,研究克拉霉素对兰索拉唑代谢的影响。结果克拉霉素显著增加兰索拉唑的AUC_0→4h、MRT和t_1/2,显著降低其CLz。克拉霉素显著降低兰索拉唑砜与兰索拉唑AUC_0→4h的比值,从0.63±0.17降至0.15±0.09（P<0.05）,兰索拉唑砜的ρ_max显著降低,MRT和t_1/2显著延长。克拉霉素对5-羟基兰索拉唑的药动学参数无明显影响。结论克拉霉素在大鼠体内对兰索拉唑CYP3A4主导的磺化代谢抑制作用明显,可明显增加兰索拉唑的生物利用度,对临床治疗消化性溃疡有积极意义。     

CYP3A catalyses schizandrin biotransformation in human,minipig and rat liver microsomes

1. Schizandrin is recognized as the major absorbed effective constituent of Fructus schisandrae, which is extensively applied in Chinese medicinal formula. The present study aimed to profile the phase I metabolites of schizandrin and identify the cytochrome P450 (CYP) isoforms involved.

2. After schizandrin was incubated with human liver microsomes, three metabolites were isolated by high-performance liquid chromatography (HPLC) and their structures were identified to be 8(R)-hydroxyl-schizandrin, 2-demethyl-8(R)-hydroxyl-schizandrin, 3-demethyl-8(R)-hydroxyl-schizandrin, by liquid chromatography-mass spectrometry (LC-MS), ¹H-nuclear magnetic resonance (NMR), and ¹³C-NMR, respectively. A combination of correlation analysis, chemical inhibition studies, assays with recombinant CYPs, and enzyme kinetics indicated that CYP3A4 was the main hepatic isoform that cleared schizandrin. Rat and minipig liver microsomes were included when evaluating species differences, and the results showed little difference among the species.

3. In conclusion, CYP3A4 plays a major role in the biotransformation of schizandrin in human liver microsomes. Minipig and rat could be surrogate models for man in schizandrin pharmacokinetic studies. Better knowledge of schizandrin’s metabolic pathway could provide the vital information for understanding the pharmacokinetic behaviours of schizandrin contained in Chinese medicinal formula.

     

肝细胞微粒体的制备和细胞色素P450氧化酶活性测定

目的：为测定人肝细胞微粒体细胞色素Ｐ４５０氧化酶的活性。方法：用差速离心法制备３例人肝细胞微粒体。结果：细胞色素Ｐ４５０的含量为０．５２３±０．００５ｎｍｏｌ·ｍｇ－１；细胞色素ｂ５为０．２８５±０．０２５ｎｍｏｌ·ｍｇ－１；氨基比林Ｎ－脱甲基酶的活力为０．５±０．６ｎｍｏｌ·ｍｇ－１；乙基吗啡Ｎ－脱甲基酶活力为０．９８±０．０８ｎｍｏｌ·ｍｇ－１。结论：Ｐ４５０酶活性影响因素较多，个体差异大。临床用药时应考虑患者的个体情况。     

豆腐果苷对人肝微粒体CYP450酶体外抑制作用研究

目的:通过评价豆腐果苷在体外对人肝微粒体CYP450酶的7种亚型酶活性的影响,预测服用豆腐果苷可能出现的食物-药物及药物-药物代谢的影响。方法:将豆腐果苷与CYP450酶7种亚型的特异性探针底物咖啡因(CYP1A2)、右美沙芬(CYP2D6)、甲苯磺丁脲(CYP2C9)、S-美芬妥因(CYP2C19)、氯唑沙宗(CYP2E1)、香豆素(CYP2A6)及咪达唑仑(CYP3A4)与人肝微粒体进行孵育反应,采用HPLC和LC-MS/MS法测定对应的7种代谢产物(1,7-二甲基黄嘌呤、去甲右美沙芬、4-羟基甲苯磺丁脲、4-羟基美芬妥因、6-羟基氯唑沙宗、7-羟基香豆素和1-羟基咪达唑仑)的浓度,与对照组比较,确定豆腐果苷对以上7种亚酶活性的影响。结果:豆腐果苷在1～100μmol.L-1时对7种酶的抑制作用均无明显统计学意义(P>0.05)。结论:豆腐果苷可能不会引起有临床意义的CYP450酶抑制现象的发生。     

甲基莲心碱在大鼠肝微粒体CYP450系统中的代谢特征

目的研究甲基莲心碱(Nef)在大鼠肝微粒体系的代谢特性,探明参与Nef代谢的CYP450亚酶种类及其在Nef代谢中的作用。方法应用CYP3A特异性诱导剂地塞米松(DEX)、CYP2B诱导剂苯巴比妥(PB)、CYP1A诱导剂β-萘黄酮(β-NF)分别对W istar大鼠进行在体诱导,建立肝微粒体温孵及NADPH再生体系,HPLC紫外检测法测定Nef及其代谢产物。观察Nef代谢消失率与代谢特征,研究上述各诱导剂和CYP3A特异性抑制剂三乙酰竹桃霉素(TAO)对Nef体外代谢的影响。结果Nef在大鼠微粒体系代谢呈饱和现象;温孵液中代谢产物生成的量与底物Nef的浓度具有良好的相关性(r=0.993);Nef在DEX、PB诱导组大鼠肝微粒体温孵液中的生物转化较对照组明显加快(P<0.01),DEX组又较PB组的Nef药物代谢率差异有显著性(P<0.01),而β-NF组未显现诱导作用,其药物代谢率分别为:DEX组80.6%±9.5%;PB组61.5%±6.7%;β-NF组20.7%±1.5%;对照组19.9%±1.6%;TAO呈量效依赖性抑制Nef在肝微粒体温孵液中的代谢。结论研究结果提示Nef具有酶促动力学代谢特性;CYP3A及CYP2B是介导Nef在大鼠体内生物转化的CYP450亚酶,其中主要参与Nef代谢的为CYP3A。     

Pharmacokinetics of verproside after intravenous and oral administration in rats

Verproside, a catalpol derivative iridoid glucoside isolated from Pseudolysimachion longifolium, is a candidate for anti-asthmatic drug. The dose-dependency of the pharmacokinetics of verproside was evaluated in rats after intravenous and oral administration. After intravenous administration of verproside (2, 5 and 10 mg/kg doses), the systemic clearance (Cl) was significantly reduced and AUC was significantly increased at 10 mg/kg dose compared to 2 and 5 mg/kg doses. The volume of distribution at steady state (V _ss) remained unchanged as the dose was increased. The extent of urinary excretion was low for both intravenous (3.3–6.2%) and oral (0.01–0.04%) doses. Isovanilloylcatalpol was identified as a metabolite after intravenous administration of verproside and showed the significant decreases in AUC and C _max at 10 mg/kg verproside dose. The reduced systemic clearance of verproside at high doses appears to be due to the saturable metabolism. Upon oral administration of verproside (20, 50 and 100 mg/kg doses), C _max was nonlinearly increased. The extent of verproside recovered from the gastrointestinal tract at 24 h after oral administration was 0.01–0.72% for all three doses studied. The absolute oral bioavailability (F) was 0.3 and 0.5% for 50 and 100 mg/kg doses, respectively. Low F appears to be due to first-pass metabolism.