3种抗菌药物对辛伐他汀在人肝微粒体中代谢的影响

目的 体外研究人肝微粒体中罗红霉素、左氧氟沙星和氟康唑分别对辛伐他汀代谢的影响。方法 分别将罗红霉素、左氧氟沙星、氟康唑与辛伐他汀在人肝微粒体中共孵育,采用UPLC-MS/MS测定辛伐他汀的浓度。结果 罗红霉素和左氧氟沙星对辛伐他汀的代谢没有影响,氟康唑剂量依赖性抑制辛伐他汀的代谢,其IC₅₀值为36.6 μmol·L^-1。结论 氟康唑显著抑制辛伐他汀的代谢,罗红霉素与左氧氟沙星对辛伐他汀在人肝微粒体中代谢无明显药物相互作用。     

格列美脲对2型糖尿病合并高血压患者氯沙坦及氯沙坦羧酸血药浓度与降压效果的影响

摘 要 目的：评估格列美脲对2型糖尿病合并高血压患者氯沙坦及活性代谢产物氯沙坦羧酸（E 3174）血药浓度与降压效果的影响。方法: 采用实效性随机对照研究,2型糖尿病合并高血压患者45例随机分为格列美脲组与对照组,两组都使用氯沙坦作为降压药,降糖措施格列美脲组选用格列美脲,对照组则选用二甲双胍、胰岛素制剂。2周后测定两组患者氯沙坦及其活性代谢产物E 3174血药浓度,并记录血压下降值。结果:格列美脲组氯沙坦血药浓度不高于对照组,E 3174血药浓度亦不低于对照组（P>0.05）。两组患者血压下降值差异无统计学意义（P>0.05）。结论:2型糖尿病合并高血压患者中格列美脲并不影响氯沙坦及活性代谢产物E 3174血药浓度,亦不影响其降压效果,提示两者可能无药物相互作用。但由于本研究样本量较小,故此结论还需在大样本临床研究中予以验证。     

环丙沙星对人肝微粒体药物酶活性的影响

目的：观察环丙沙星对人肝微粒体药物代谢酶活性的影响。方法：用正常人新鲜肝组织低温匀浆,低温超速离心分离肝微粒体,测定肝微粒体细胞色素P450（CP450）的含量。以环丙沙星为处理因素,作肝微粒体药物代谢活性测定的体外试验。反应体系中微粒体蛋白的终浓度为1．0g/L,环丙沙星的终浓度为400mg/L。结果：环丙沙星对人肝微粒体药物代谢酶的活性抑制有选择性,对不同酶其抑制强度不同。对多种酶的抑制强弱顺序为：戊巴比妥侧链羟化酶＞苯并芘羟化酶＞乙基吗啡N－脱甲基酶, 其抑制率分别为0．34、0．30、和0．18。结论：环丙沙星对人肝微粒体多种药物代谢酶活性有明显的抑制作用。提示对肝功异常者、使用戊巴比妥钠麻醉的病人、经常服用吗啡类药物及高苯比芘含量环境工作人员该类药物应慎用。     

山姜素在人肝微粒体的葡萄糖醛酸化反应研究

目的研究体外肝微粒体孵育体系中山姜素的葡萄糖醛酸化代谢情况,鉴定参与山姜素葡萄糖醛酸化代谢的UGT亚型。方法用体外肝微粒体孵育体系,用HPLC-UV检测方法,检测山姜素的葡萄糖醛酸化代谢情况。将代谢产物进行纯化后,用质谱(MS)和核磁共振(NMR)法进一步鉴定其结构。用商业化重组表达的UGT单酶,鉴定代谢产物的结构和归属可能参与山姜素葡萄糖醛酸化代谢反应的葡萄糖醛酸转移酶(UGTs)亚型。结果山姜素葡萄糖醛酸代谢产生一个代谢产物,经结构鉴定为山姜素-氧-单葡萄糖醛酸化产物。人肝微粒体代谢山姜素的动力学行为,符合米方程且动力学参数:Vmax=(101.9±3.0)nmol·min-1·mg-1·pro,Km=(40.6±3.6)μmol·L-1。UGT1A1、UGT1A3、UGT1A9和UGT2B15均参与了山姜素的葡萄糖醛酸化反应。结论山姜素在人肝微粒体孵育体系中会被代谢成为一个单葡萄糖醛酸化产物,且归属了参与的UGT酶。     

利多卡因在人肝微粒体中的体外生物转化

目的 建立人肝微粒体体外生物转化利多卡因的方法。方法分别改变反应体系中人肝微粒体的浓度、生物转化时间、利多卡因的浓度，以高效液相色谱(HPLC)法测定利多卡因及其代谢产物单乙基甘氨二甲基苯酰胺(MEGX)和甘氨二甲基苯酰胺(GX)的含量。结果最佳的生物转化条件为：2.0 mg·L^-1利多卡因在1.0 g·L^-1微粒体中，生物转化60 min。结论该方法快速有效，可用于利多卡因在人肝微粒体体外代谢的研究。     

二氢吡啶类钙通道阻滞药对人肝微粒体中氯吡格雷代谢的抑制作用

目的:研究二氢吡啶类(DHPs)钙通道阻滞药硝苯地平、氨氯地平、非洛地平对人肝微粒体中氯吡格雷代谢的影响,为临床合理用药提供参考。方法:采用人肝微粒体体外代谢模型,将0.1、1、5、10、25、50、100、200μmol/L的硝苯地平、氨氯地平、非洛地平分别与氯吡格雷(20μmol/L)在人肝微粒体中进行共孵育,孵育15 min后加入5倍体积的含内标氯雷他定的冰乙腈溶液(内标终质量浓度为500 ng/ml)终止反应。沉淀蛋白后取上清液,采用超高效液相色谱-质谱(UPLC-MS)法检测氯吡格雷的浓度,以不加DHPs药物为阴性对照计算各DHPs药物作用下氯吡格雷的代谢抑制率。结果:硝苯地平、氨氯地平、非洛地平对人肝微粒体中氯吡格雷的代谢均有一定程度的抑制作用,但200μmol/L浓度时代谢抑制率仍不及50%,提示半数抑制浓度均大于200μmol/L。结论:DHPs药物能抑制人肝微粒体中氯吡格雷的代谢,但抑制作用不强。提示DHPs药物不与氯吡格雷发生相互作用,不会影响两者临床联合使用。     

人肝微粒体CYP亚型在新型吲哚醌类化合物629代谢中的作用

目的研究人肝微粒体重组体系中不同CYP亚型在丝裂霉素C(MMC)的衍生物5-氮丙啶-3-羟甲基-1-甲基吲哚-4,7-二酮[5-(aziridin-1-yl)-3-hydroxymethyl-1-methylin-dole-4,7-dione,简称629]代谢中的作用。方法不同浓度629与人肝脏微粒体共孵育,给予细胞不同CYP亚型特异性抑制剂的处理,用高压液相色谱法(high pressure liquid chro-matography,HPLC)分离、检测629的消失情况。结果HPLC检测到629在肝脏微粒体中的代谢遵循酶动力学剂量效应关系,Km值为336μmol·L-1。P450酶系中CYP1A2、CYP2B6和CYP2A6被抑制后,可影响629的代谢(P<0.05),并且3者中CYP1A2的影响较大,但三者间差异无显著性(P>0.05);而CYP3A4、CYP2C19、CYP2C9、CYP2E1和CYP2D6对629的代谢无影响(P>0.05)。结论新型吲哚醌类生物还原物629可在肝脏代谢,其中CYP1A2、CYP2B6和CYP2A6可参与629的代谢,这为新型生物还原活性物设计、开发及临床上的合理用药具有重大的意义。     

磷酸川芎嗪与大鼠肝微粒体相互作用的研究

Sprague-Dawley6大鼠ig50、100和300mg/kg磷酸川芎嗪,对肝微粒体细胞色素P-450酶系无显著性影响。苯巴比妥诱导P-450b后再ig磷酸川芎嗪,其体内血药浓度明显低于正常对照组,说明川芎嗪在体内代谢可能和肝微粒体细胞色素P-450酶系统中的P-450b同功酶有关。     

UPLC-MS/MS快速鉴定乔松素在人肝微粒体中的代谢产物

目的 以超高效液相色谱质谱联用法(UPLC-MS/MS)快速鉴定乔松素在人肝微粒体中的代谢产物。 方法 以人肝微粒体体外孵育体系对乔松素进行代谢研究,以UPLC-MS/MS鉴定乔松素的体外代谢产物。 结果 建立了乔松素的体外代谢孵育体系,UPLC-MS/MS在6 min内检测到乔松素的4个代谢产物,分别鉴定为柚皮素、5,6,7-三羟基二氢黄酮、5,7,8 -三羟基二氢黄酮和乔松素-7-葡萄糖醛酸苷,这4个代谢产物均为首次发现的乔松素人肝微粒体体外代谢产物。 结论 乔松素在人肝微粒体中的主要代谢途径为羟基化和葡萄糖醛酸化,5,7,8 -三羟基二氢黄酮是其主要羟基化产物,乔松素-7-葡萄糖醛酸苷可能为乔松素的主要代谢失活形式。     

荧光光谱法研究青蒿素及双氢青蒿素与肝微粒体的相互作用

目的研究抗疟药青蒿素(ART)与双氢青蒿素(DHA)和大鼠肝微粒体(RLM)以及人肝微粒体(HLM)之间的相互作用。方法在模拟人体生理条件下,采用荧光光谱法,得出青蒿素、DHA与RLM和HLM的结合参数。结果青蒿素和DHA对RLM和HLM的猝灭机制不同,它们对RLM的猝灭机制均为静态猝灭,而对HLM的猝灭作用为混合猝灭;其相互间作用力均为氢键和范德华力,其结合反应均为自发的热力学反应。结论青蒿素和DHA对大鼠和人肝微粒体均有结合,且结合力存在种属差异,同时青蒿素和DHA与同种肝微粒体的结合能力也存在差异。     

Stereoselective glucuronidation of formoterol by human liver microsomes

AIMS: Formoterol is a beta2-adrenoceptor agonist marketed as a racemic mixture of the active (R; R)- and inactive (S; S)-enantiomers (rac-formoterol). The drug produces prolonged bronchodilation by inhalation but there is significant interpatient variability in duration of effect. Previous work has shown that in humans formoterol is metabolized by conjugation with glucuronic acid but little is known about the stereoselectivity of this reaction. The aim of the present study was to investigate the glucuronidation of formoterol enantiomers in vitro by human liver microsomes. METHODS: The kinetics of formation of formoterol glucuronides during incubation of racemate and of single formoterol enantiomers with human liver microsomes (n=9) was characterized by chiral h.p.l.c. assay. RESULTS: The kinetics of glucuronidation of the two formoterol enantiomers obeyed the Michaelis-Menten equation. Glucuronidation of formoterol was stereoselective and occurred more than two times faster for (S; S)-formoterol than for (R; R)-formoterol. In incubations with single formoterol enantiomers, the median (n=9) Km values for (R; R)-glucuronide and (S; S)-glucuronide were 827.6 and 840.4 microm, respectively, and the median V max values were 2625 and 4304 pmol min-1 mg-1, respectively. Corresponding values determined in incubations with rac-formoterol were 357.2 and 312.1 microm and 1435 and 2086 pmol min-1 mg-1 for (R; R)- and (S; S)-glucuronide, respectively. Interindividual variation was large with the ratio of V max/Km (S; S/R; R) ranging from 0.57 to 6.90 for incubations with rac-formoterol. CONCLUSIONS: Our study demonstrates that glucuronidation of formoterol by human liver microsomes is stereoselective and subject to high interindividual variability. These findings suggest that clearance of formoterol in humans is subject to variable stereoselectivity which could explain the variation in duration of bronchodilation produced by inhaled formoterol in patients with asthma.     

In-vitro metabolism of glycyrrhetinic acid by human and rat liver microsomes and its interactions with six CYP substrates

Objectives Glycyrrhetinic acid is the main metabolite of glycyrrhizin and the main active component of Licorice root. This study was designed to investigate the in‐vitro metabolism of glycyrrhetinic acid by liver microsomes and to examine possible metabolic interactions that glycyrrhetinic acid may have with other cytochrome P450 (CYP) substrates. Methods Glycyrrhetinic acid was incubated with rat liver microsomes (RLM) and human liver microsomes (HLM). Liquid chromatography tandem mass spectrometry was used for glycyrrhetinic acid or substrates identification and quantification. Key findings The K_m and V_max values for HLM are 33.41 µm and 2.23 nmol/mg protein/min, respectively; for RLM the K_m and V_max were 24.24 µm and 6.86 nmol/mg protein/min, respectively. CYP3A4 is likely to be the major enzyme responsible for glycyrrhetinic acid metabolism in HLM while CYP2C9 and CYP2C19 are considerably less active. Other human CYP isoforms have minimal or no activity toward glycyrrhetinic acid. The interactions of glycyrrhetinic acid and six CYP substrates, such as phenacetin, diclofenac, (S)‐mephenytoin, dextromethorphan, chlorzoxazone and midazolam were also investigated. The inhibitory action of glycyrrhetinic acid was observed in CYP2C9 for 4‐hydroxylation of diclofenac, CYP2C19 for 4′‐hydroxylation of (S)‐mephenytoin and CYP3A4 for 1′‐hydroxylation of midazolam with half maximal inhibitory concentration (IC50) values of 4.3‐fold, 3.8‐fold and 9.6‐fold higher than specific inhibitors in HLM, respectively. However, glycyrrhetinic acid showed relatively little inhibitory effect (IC50 > 400 µm ) on phenacetin O‐deethylation, dextromethorphan O‐demethylation and chlorzoxazone 6‐hydroxylation. Conclusions The study indicated that CYP3A4 is likely to be the major enzyme responsible for glycyrrhetinic acid metabolism in HLM while CYP2C9 and CYP2C19 are considerably less active. The results suggest that glycyrrhetinic acid has the potential to interact with a wide range of xenobiotics or endogenous chemicals that are CYP2C9, CYP2C19 and CYP3A4 substrates.     

Characterization of in vitro metabolites of cudratricusxanthone A in human liver microsomes

Cudratricusxanthone A (CTXA), isolated from the roots of Cudrania tricuspidata, exhibits several biological activities; however, metabolic biotransformation was not investigated. Therefore, metabolites of CTXA were investigated and the major metabolic enzymes engaged in human liver microsomes (HLMs) were characterized using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). CTXA was incubated with HLMs or human recombinant CYPs and UGTs, and analysed by an LC‐MS/MS equipped electrospray ionization (ESI) to qualify and quantify its metabolites. In total, eight metabolites were identified: M1–M4 were identified as mono‐hydroxylated metabolites during Phase I, and M5–M8 were identified as O‐glucuronidated metabolites during Phase II in HLMs. Moreover, these metabolite structures and a metabolic pathway were identified by elucidation of MSⁿ fragments and formation by human recombinant enzymes. M1 was formed by CYP2D6, and M2–M4 were generated by CYP1A2 and CYP3A4. M5–M8 were mainly formed by UGT1A1, respectively. While investigating the biotransformation of CTXA, eight metabolites of CTXA were identified by CYPs and UGTs; these data will be valuable for understanding the in vivo metabolism of CTXA. Copyright © 2015 John Wiley & Sons, Ltd.     

Effects of anticancer drugs on the metabolism of the anticancer drug 5,6-dimethylxanthenone-4-acetic (DMXAA) by human liver microsomes

AIMS: To investigate the effects of various anticancer drugs on the major metabolic pathways (glucuronidation and 6-methylhydroxylation) of DMXAA in human liver microsomes. METHODS: The effects of various anticancer drugs at 100 and 500 microM on the formation of DMXAA acyl glucuronide (DMXAA-G) and 6-hydroxymethyl-5-methylxanthenone-4-acetic acid (6-OH-MXAA) in human liver microsomes were determined by high performance liquid chromatography (h.p.l.c.). For those anticancer drugs showing significant inhibition of DMXAA metabolism, the inhibition constants (Ki) were determined. The resulting in vitro data were extrapolated to predict in vivo changes in DMXAA pharmacokinetics. RESULTS: Vinblastine, vincristine and amsacrine at 500 microM significantly (P < 0.05) inhibited DMXAA glucuronidation (Ki = 319, 350 and 230 microM, respectively), but not 6-methylhydroxylation in human liver microsomes. Daunorubicin and N-[2-(dimethylamino)-ethyl]acridine-4-carboxamide (DACA) at 100 and 500 microM showed significant (P < 0.05) inhibition of DMXAA 6-methylhydroxylation (Ki = 131 and 0.59 microM, respectively), but not glucuronidation. Other drugs such as 5-fluoroucacil, paclitaxel, tirapazamine and methotrexate exhibited little or negligible inhibition of the metabolism of DMXAA. Pre-incubation of microsomes with the anticancer drugs (100 and 500 microM) did not enhance their inhibitory effects on DMXAA metabolism. Prediction of DMXAA-drug interactions in vivo based on these in vitro data indicated that all the anticancer drugs investigated except DACA appear unlikely to alter the pharmacokinetics of DMXAA, whereas DACA may increase the plasma AUC of DMXAA by 6%. CONCLUSIONS: These results indicate that alteration of the pharmacokinetics of DMXAA appears unlikely when used in combination with other common anticancer drugs. However, this does not rule out the possibility of pharmacokinetic interactions with other drugs used concurrently with this combination of anticancer drugs.     

尼莫地平在人肝微粒体内的代谢

:采用人肝微粒体在体外研究尼莫地平 (Nim)在人体内的代谢物及代谢途径 . Nim在人肝微粒体内被迅速代谢成 3个代谢物 ,分别是 Nim二氢吡啶环脱氢代谢物 M1,二氢吡啶环侧链脱甲基代谢物M2 ,二氢吡啶环脱氢及其侧链脱甲基代谢物 M3.Nim在人肝微粒体中的最初的两步代谢反应是其二氢吡啶环脱氢氧化及其侧链脱甲基反应 ,两者的代谢产物可以被进一步代谢为代谢物 M3.CYP3A的特异性抑制剂醋竹桃霉素和酮康唑可以抑制Nim的二氢吡啶环脱氢氧化及其侧链脱甲基反应 ,使 Nim的代谢速率明显下降 ,结果提示 CYP3A参与了 Nim在人肝微粒体内的代谢     

氟伐他汀和格列美脲人体内的药动学相互作用

目的:探讨氟伐他汀(FV)和格列美脲(GMD)合用后其药动学特征和相互作用。方法:12名健康男性志愿者随机分成6组,按拉丁方设计先后服用FV(40 mg·d~(-1),8d),GMD(4 mg·d~(-1),7d),FV (40 mg·d~(-1),8d)+GMD(4mg·d~(-1),8d)。采用HPLC测定血药浓度,用DAS 2.0软件对数据进行处理,计算药动学参数。结果:合用GMD前后,FV的药动学参数无明显改变;合用FV前后,GMD的c_(max)~(ss)、c_(min)~(ss)、c_(av)~(ss)、AUC_(0-24)~(ss)、t_(1/2)和MRT显著增加(P<0.05),CL(F)和DF显著减少(P<0.05)。结论:2药合用后GMD的肝脏代谢受到抑制,临床合用应注意监测病人体内GMD的血药浓度,避免不良反应的发生。     

Identification of CYP isozymes involved in benzbromarone metabolism in human liver microsomes

Benzbromarone (BBR) is metabolized to 1′‐hydroxy BBR and 6‐hydroxy BBR in the liver. 6‐Hydroxy BBR is further metabolized to 5,6‐dihydroxy BBR. The aim of this study was to identify the CYP isozymes involved in the metabolism of BBR to 1′‐hydroxy BBR and 6‐hydroxy BBR and in the metabolism of 6‐hydroxy BBR to 5,6‐dihydroxy BBR in human liver microsomes. Among 11 recombinant P450 isozymes examined, CYP3A4 showed the highest formation rate of 1′‐hydroxy BBR. The formation rate of 1′‐hydroxy BBR significantly correlated with testosterone 6β‐hydroxylation activity in a panel of 12 human liver microsomes. The formation of 1′‐hydroxy BBR was completely inhibited by ketoconazole in pooled human liver microsomes. On the other hand, the highest formation rate of 6‐hydroxy BBR was found in recombinant CYP2C9. The highest correlation was observed between the formation rate of 6‐hydroxy BBR and diclofenac 4′‐hydroxylation activity in 12 human liver microsomes. The formation of 6‐hydroxy BBR was inhibited by tienilic acid in pooled human liver microsomes. The formation of 5,6‐dihydroxy BBR from 6‐hydroxy BBR was catalysed by recombinant CYP2C9 and CYP1A2. The formation rate of 5,6‐dihydroxy BBR was significantly correlated with diclofenac 4′‐hydroxylation activity and phenacetin O‐deethylation activity in 12 human liver microsomes. The formation of 5,6‐dihydroxy BBR was inhibited with either tienilic acid or α‐naphthoflavone in human liver microsomes. These results suggest that (i) the formation of 1′‐hydroxy BBR and 6‐hydroxy BBR is mainly catalysed by CYP3A4 and CYP2C9, respectively, and (ii) the formation of 5,6‐dihydroxy BBR is catalysed by CYP2C9 and CYP1A2 in human liver microsomes. Copyright © 2012 John Wiley & Sons, Ltd.     

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。     

The metabolism of valerylfentanyl using human liver microsomes and zebrafish larvae

Valerylfentanyl, a novel synthetic opioid less potent than fentanyl, has been reported in biological samples, but there are limited studies on its pharmacokinetic properties. The goal of this study was to elucidate the metabolism of valerylfentanyl using an in vitro human liver microsome (HLM) model compared with an in vivo zebrafish model. Nineteen metabolites were detected with N-dealkylation—valeryl norfentanyl and hydroxylation as the major metabolic pathways. The major metabolites in HLMs were also detected in 30 day postfertilization zebrafish. An authentic liver specimen that tested positive for valerylfentanyl, among other opioids and stimulants, revealed the presence of a metabolite that shared transitions and retention time as the hydroxylated metabolite of valerylfentanyl but could not be confirmed without an authentic standard. 4-Anilino-N-phenethylpiperidine (4-ANPP), a common metabolite to other fentanyl analogs, was also detected. In this study, we elucidated the metabolic pathway of valerylfentanyl, confirmed two metabolites using standards, and demonstrated that the zebrafish model produced similar metabolites to the HLM model for opioids.