转运体介导中药与化学药相互作用研究进展

ATP结合盒转运体家族和溶质转运体家族的转运体参与众多的中药与化学药相互作用过程,因其可介导内外源性药物及其代谢物的跨膜转运。转运体同细胞色素P450酶类似,会对特征底物的血药浓度和组织分布产生一定影响,从而改变药物的药效或者毒副作用。本文综述了具有重要临床意义的P-糖蛋白、乳腺癌耐药蛋白、有机阴离子转运体、有机阳离子转运体和有机阴离子转运多肽等5种转运体所介导的中药与化学药相互作用,以期为临床联合用药提供一定的理论依据。     

肝脏“代谢-转运互作”及其对药物药代动力学、疗效和毒性影响的研究进展

肝脏是药物代谢和排泄的主要器官。肝脏药物代谢酶和膜转运体对肝细胞内药物处置及其临床疗效和毒性产生重要影响。近年来,国内外学者发现被称为"代谢-转运互作"的动力学现象,其对药物药代动力学(生物利用度)、药物相互作用具有显著影响。药物代谢酶与转运体间的功能相互作用是目前药物代谢和药代动力学研究的热点之一。本文对肝脏代谢-转运互作进行了探究,并系统阐述了这种互作对药物(特别是Ⅱ相药物代谢)的药物相互作用、药代动力学、临床疗效和毒性反应的影响。今后应进一步阐明肝脏代谢-转运互作机制,有助于研究体内药物处置及药物相互作用,为临床合理用药提供新思路和新技术。     

转运体在药物肾脏排泄中的重要作用

转运体是细胞膜上的功能性蛋白,在肾脏中表达广泛,对许多内源性或外源性物质的肾脏分泌及重吸收起到了至关重要的作用。许多药物（包括有机阴离子药物、有机阳离子药物及肽类药物等）在肾脏排泄的过程中,经主要集中在近端肾小管的转运体主动转运介导。临床合用某些药物时可能在肾脏发生转运体介导的相互作用。从肾脏主要转运体的分布及功能出发,综述其在药物肾脏排泄中的作用。     

药用辅料对药物转运体影响研究现状

药用辅料是药物制剂中不可缺少的组成成分,其通常作为惰性物质影响药物制剂的崩解、溶出等过程。近年来,随着研究的深入,许多常见药用辅料如表面活性剂,稳定剂,润滑剂等均在体内外表现出一定的生理和药理活性。研究表明药用辅料可通过影响药物转运体和肝药酶,进而影响药物的体内处置过程,导致药动学和药效学行为发生改变,甚至引起临床药物不良反应的发生。药用辅料对常见ATP结合盒转运体,如P-糖蛋白转运体、乳腺癌耐药蛋白和多药耐药相关蛋白,以及溶质载体转运体,如有机阴离子转运肽,有机阴离子转运体,有机阳离子转运体和寡肽转运蛋白等多具有一定的抑制作用,也有少量报道辅料对转运体具有诱导作用,但其抑制和诱导机制尚未完全阐明。本文就目前药用辅料对药物转运体影响的研究及其可能存在的机制展开综述,以期为仿制药及创新药物制剂方面研发提供新思路。     

肾近端小管细胞系在药物肾毒性评价中的应用

肾脏是药物毒副作用的主要靶器官，而肾近端小管拥有庞大的转运系统和丰富的生物转化酶，对外源性毒物的损害特别敏感，是研究药物肾毒性可靠的细胞模型。利用肾近端小管上皮细胞系在药物开发早期优化筛选先导化合物，并比较结构相似化合物的相对肾毒性，是近年来药物发现毒理学研究的重点和热点。本文就国内外常用的几株肾近端小管上皮细胞系的生理生化特点、常见检测终点和指标及其在药物研究开发中的应用作一简要综述。     

代谢酶和转运体介导的中药-西药相互作用的药动学机制研究进展

随着中草药的广泛应用,中药-西药相互作用(herb-drug interaction,HDI)问题日益凸显。代谢酶和转运体是影响药物体内处置过程的重要因素,其表达和功能的改变常常引起药代动力学的变化,是药物相互作用的主要靶点。代谢酶负责药物的代谢清除,主要包括细胞色素P450超家族(CYP)、UDP-葡萄糖醛酸基转移酶(UGT)以及磺酸化酶(SULT);转运体参与药物的口服吸收、体内分布以及排泄,主要包括肠道转运体、肾脏转运体、肝脏转运体以及脑转运体等。葛根、银杏叶、人参、圣约翰草等中草药在临床上应用广泛,且常与西药联合应用,其成分与代谢酶以及转运体存在相互作用,容易产生HDI。本文综述代谢酶、转运体介导的HDI的药代动力学机制,阐述常用中草药在与西药联合应用时应注意的问题。     

转运体介导的核苷类抗病毒药与其他药物联合应用的相互作用研究

有机阳离子转运体、有机阴离子转运体、P糖蛋白、多药耐药蛋白和核苷转运体是机体内参与核苷类抗病毒药转运及消除的蛋白,转运体通过介导药物的摄取和排出,能够调节体内抗病毒药的浓度,从而影响药物在体内的药动学和药效学行为。本文通过对核苷类抗病毒药和机体转运体相关文献进行综述,探究转运体介导的核苷类抗病毒药与其他药物联合应用时的相互作用,为临床合理用药提供参考。     

血脑屏障的膜蛋白对药物转运及临床治疗的影响

P-糖蛋白,乳腺癌耐药蛋白,多药耐药相关蛋白,有机阴离子转运多肽,有机阴离子转运体,有机阳离子转运体,单羧酸转运体是血脑屏障上常见的膜蛋白,它们与药物的中枢转运密切相关。本文对上述蛋白的底物、转运特点及对临床治疗的影响做了系统的回顾,为药物的优化使用提供参考。     

大黄酸对药物转运体和代谢酶影响的研究进展

药物转运体和药物代谢酶是影响药物体内处置过程中至关重要的因素。大黄酸作为传统中药大黄的主要活性成分,具有广泛药理活性。研究发现,大黄酸与药物转运体和代谢酶密切相关,能够直接激活或抑制多种转运体的功能及其蛋白表达。而且大黄酸对药物代谢酶细胞色素P450（CYP450）的功能及其蛋白表达同样有抑制作用。因此,大黄酸与其他药物合用时,可能发生基于药动学的药物相互作用（drug-drug interaction,DDI）。从药物转运体和代谢酶的体内分布、大黄酸对转运体及代谢酶的影响等方面进行综述。     

药物转运体和代谢酶在抗生素药动学中的作用

近年来,对体内药物转运体的研究取得了重大进展,越来越多的转运体被发现及研究,其对药物的跨膜转运,具有重要的意义。各种转运体包括摄取转运体和外排转运体对药物的体内过程以及药物相互作用均有着重要影响。研究表明大多数抗生素的体内过程都与转运体和代谢酶有关,因此,归纳总结了转运体和代谢酶在抗生素的药动学和药物相互作用中的最新研究进展,为临床合理用药提供参考。     

转运蛋白在药物肾脏转运中的重要作用

肾脏转运蛋白对药物在体内排泄和重吸收过程重要作用.本文对肾脏转运蛋白的种类、分布、作用机制及其对药物排泄过程的影响和可能产生的药物相互作用做了综述.     

Mechanisms and clinical implications of renal drug excretion.

The body defends itself against potentially harmful compounds like drugs, toxic compounds, and their metabolites by elimination, in which the kidney plays an important role. Renal clearance is used to determine renal elimination mechanisms of a drug, which is the result of glomerular filtration, active tubular secretion and reabsorption. The renal proximal tubule is the primary site of carrier-mediated transport from blood to urine. Renal secretory mechanisms exists for, anionic compounds and organic cations. Both systems comprises several transport proteins, and knowledge of the molecular identity of these transporters and their substrate specificity has increased considerably in the past decade. Due to overlapping specificities of the transport proteins, drug interactions at the level of tubular secretion is an event that may occur in clinical situation. This review describes the different processes that determine renal drug handling, the techniques that have been developed to attain more insight in the various aspects of drug excretion, the functional characteristics of the individual transport proteins, and finally the implications of drug interactions in a clinical perspective.     

Modeling and predicting drug pharmacokinetics in patients with renal impairment

Current guidance issued by the US FDA to assess the impact of renal impairment on the pharmacokinetics of a drug under development has recently been updated to include evaluation of drugs with nonrenal elimination routes. Renal impairment not only affects elimination of the drug in the kidney, but also the nonrenal route of drugs that are extensively metabolized in the liver. Renal failure may influence hepatic drug metabolism either by inducing or suppressing hepatic enzymes, or by its effects on other variables such as protein binding, hepatic blood flow and accumulation of metabolites. Prior simulation of the potential exposure of individuals with renal impairment may help in the selection of a safe and effective dosage regimen. In this article, we discuss the application of a systems biology approach to simulate drug disposition in subjects with renal impairment.     

Dealing with the complex drug–drug interactions: Towards mechanistic models

Unmanageable severe adverse events caused by drug‐drug interactions (DDIs), leading to market withdrawals or restrictions in the clinical usage, are increasingly avoided with the improvement in our ability to predict such DDIs quantitatively early in drug development. However, significant challenges arise in the evaluation and/or prediction of complex DDIs caused by inhibitor drugs and/or metabolites that affect not one but multiple pathways of drug clearance. This review summarizes the discussion topics at the 2013 AAPS symposium on “Dealing with the complex drug‐drug interactions: towards mechanistic models”. Physiologically based pharmacokinetic (PBPK) models, in combination with the established in vitro‐to‐in vivo extrapolations of intestinal and hepatic disposition, have been successfully applied to predict clinical pharmacokinetics and DDIs, especially for drugs with CYP‐mediated metabolism, and to explain transporter‐mediated and complex DDIs. Although continuous developments are being made towards improved mechanistic prediction of the transporter‐enzyme interplay in the hepatic and intestinal disposition and characterizing the metabolites contribution to DDIs, the prediction of DDIs involving them remains difficult. Regulatory guidelines also recommended use of PBPK modeling for the quantitative prediction and evaluation of DDIs involving multiple perpetrators and metabolites. Such mechanistic modeling approaches culminate to the consensus that modeling is helpful in predicting DDIs or quantitatively rationalizing the clinical findings in complex situations. Furthermore, they provide basis for the prediction and/or understanding the pharmacokinetics in populations like patients with renal impairment, pediatrics, or various ethnic groups where the conduct of clinical studies might not be feasible in early drug development stages and yet some guidance on management of dosage is necessary. Copyright © 2014 John Wiley & Sons, Ltd.     

In vitro and in vivo methods to assess pharmacokinetic drug– drug interactions in drug discovery and development

Drug–drug interactions (DDIs) caused by the co-administration of multiple drugs are major safety concerns in the clinic. Several drugs have been withdrawn from the market due to perpetrator or victim DDIs. Strategies have been developed to assess DDI risks early in drug discovery to reduce DDI liabilities. High-to-medium throughput assays are available to identify undesirable scaffolds and to guide structural modifications to minimize DDIs. Definitive methods are used at later stages of drug discovery and development to provide a more accurate measurement of DDI parameters and to enable clinical translations. Physiologically based pharmacokinetic modeling and simulations are powerful tools to accurately predict DDIs and to assess risks in the clinic. Although significant advances have been made over the years, many challenges remain for clinical DDI translations. This includes DDIs involving non-cytochrome P450 enzymes, transporters, enzyme-transporter interplay, indirect effects from biologics, and pharmacodynamic based DDI. This review focuses on methods that are used to assess hepatic DDIs caused by enzyme inhibition and induction.     

Overview of SLC22A and SLCO families of drug uptake transporters in the context of cancer treatments

The effectiveness of many anticancer agents is dependent on their disposition to the intracellular space of cancerous tissue. Accumulation of anticancer drugs at their sites of action can be altered by both uptake and efflux transport proteins, however the majority of research on the disposition of anticancer drugs has focused on drug efflux transporters and their ability to confer multidrug resistance. Here we review the roles of uptake transporters of the SLC22A and SLCO families in the context of cancer therapy. The many first-line anticancer drugs that are substrates of organic cation transporters (OCTs) organic cation/carnitine transporters (OCTNs) and organic anion- transporting polypeptides (OATPs) are summarized. In addition, where data is available a comparison of the localization of drug uptake transporters in healthy and cancerous tissues is provided. Expression of drug uptake transporters increases the sensitivity of cancer cell lines to anticancer substrates. Furthermore, early observational studies have suggested a causal link between drug uptake transporter expression and positive outcome in some cancers. Quantification of drug transporters by mass spectrometry will provide an essential technique for generation of expression data during future observational clinical studies. Screening of drug uptake transporter expression in primary tumors may help differentiate between susceptible and resistant cancers prior to therapy.     

Pharmacokinetic interplay of phase II metabolism and transport: a theoretical study

Understanding of the interdependence of cytochrome P450 enzymes and P-glycoprotein in disposition of drugs (also termed "transport-metabolism interplay") has been significantly advanced in recent years. However, whether such "interplay" exists between phase II metabolic enzymes and efflux transporters remains largely unknown. The objective of this article is to explore the role of efflux transporters (acting on the phase II metabolites) in disposition of the parent drug in Caco-2 cells, liver, and intestine via simulations utilizing a catenary model (for Caco-2 system) and physiologically based pharmacokinetic (PBPK) models (for the liver and intestine). In all three models, "transport-metabolism interplay" (i.e., inhibition of metabolite efflux decreases the metabolism) can be observed only when futile recycling (or deconjugation) occurred. Futile recycling appeared to bridge the two processes (i.e., metabolite formation and excretion) and enable the interplay thereof. Without futile recycling, metabolite formation was independent on its downstream process excretion, thus impact of metabolite excretion on its formation was impossible. Moreover, in liver PBPK model with futile recycling, impact of biliary metabolite excretion on the exposure of parent drug [(systemic (reservoir) area under the concentration-time curve (AUC(R1))] was limited; a complete inhibition of efflux resulted in AUC(R1) increases of less than 1-fold only. In intestine PBPK model with futile recycling, even though a complete inhibition of efflux could result in large elevations (e.g., 3.5-6.0-fold) in AUC(R1), an incomplete inhibition of efflux (e.g., with a residual activity of ≥ 20% metabolic clearance) saw negligible increases (<0.9-fold) in AUC(R1). In conclusion, this study presented mechanistic observations of pharmacokinetic interplay between phase II enzymes and efflux transporters. Those studying such "interplay" are encouraged to adequately consider potential consequences of inhibition of efflux transporters in humans.     

Role of organic cation transporter OCT2 and multidrug and toxin extrusion proteins MATE1 and MATE2-K for transport and drug interactions of the antiviral lamivudine

The antiviral lamivudine is cleared predominantly by the kidney with a relevant contribution of renal tubular secretion. It is not clear which drug transporters mediate lamivudine renal secretion. Our aim was to investigate lamivudine as substrate of the renal drug transporters organic cation transporter 2 (OCT2) and multidrug and toxin extrusion proteins MATE1 and MATE2-K.