Caco-2细胞模型——药物吸收研究的有效“工具”

吸收过程是决定口服药物生物利用度的重要因素 ,然而很多药物的吸收机制还不明确。Caco 2细胞模型是目前最好的体外吸收模型 ,在药物的吸收过程及吸收机制的研究方面有广泛的应用 ,尤其在中药吸收研究方面 ,Caco 2细胞模型的应用成为目前的热点。另外 ,Caco 2细胞模型在药物代谢方面也有应用。因此 ,Caco 2细胞模型将成为药物吸收研究的重要手段 ,有助于加快新药筛选和开发的速度。     

Caco—2模型在肽类药物吸收特性研究中的应用

Caco－2模型作为药物离体口服特性筛选模型,已广泛用于药物在小肠处的各种转运机制研究。该模型来源于人体结肠癌细胞,含有多种代谢酶,接近体内吸收的实际情况,可区分不同药物吸收时摄取和跨膜转运过程。本文对Caco－2模型的建立及其近年来在太类及肽类类似物吸收特性研究方面的应用作一综述。     

Caco-2细胞模型在药物动力学研究中的应用

药物动力学研究中 ,涵盖着吸收、分布、生物转化和排泄四个过程。口服给药是临床最常见的途径 ,药物发挥作用 ,关键在于吸收。吸收过程和排泄过程的研究对药物动力学而言至关重要。近年来 ,通过肠上皮细胞的培养来作为研究药物吸收、代谢机制的体外模型取得令人鼓舞的进展。最具有代表性的细胞是来自结肠癌细胞系的Caco 2细胞 (thehumancolonadenocarcinomacelllines的简称 )。研究发现了药物透过Caco 2单细胞层的体外过程与药物口服后在肠中的吸收和代谢有良好的相关性 ,使得Caco 2细胞成为研究药物吸收和代谢的最经典的体外细胞模型[1,2…     

Caco-2细胞模型在药物研究中的应用

Caco2细胞模型广泛用于药物的吸收、代谢以及毒性研究,Caco2细胞模型作为药物吸收研究的一种快速筛选工具,在抗癌药物、无机药物、中药的研究方面得到了广泛的应用,成为药物研究的重要手段。     

肠道药物转运体及其研究方法

口服药物在肠道中的吸收是决定药物生物利用度的重要因素。肠道中有许多药物膜转运蛋白介导药物的吸收、分布、排泄及药物相互作用等。明确其转运机制有利于提高药物的安全性和有效性,从而指导临床合理用药。通过体内外方法预测药物经转运体在肠道中的转运情况。本文介绍了肠道内转运药物的主要膜转运蛋白,阐述了口服药物经肠道转运机制,概括了研究肠道药物转运体的主要研究方法,并对多种体内外转运体研究方法的优缺点进行了比较。     

Caco-2细胞模型在天然药物吸收研究中的应用

目的Caco-2细胞模型为经典的口服药物体外吸收模型。此文介绍了Caco-2细胞模型的来源与特点,综述了Caco-2细胞模型在天然药物吸收研究中的应用现状,并对Caco-2细胞模型在天然药物研究中的应用前景进行了探讨。     

体外Caco-2细胞模型在药物吸收中的应用进展

目的:介绍Caco-2细胞模型的特征及其在药物吸收中的应用.方法:分析国内外近期相关文献,对Caco-2细胞模型在药物吸收动力学中的研究进行概述.结果:Caco-2细胞模型用于药物动力学研究,可预测药物在体内的吸收和代谢.结论:体外Caco-2细胞模型在药物吸收过程的研究中有重要意义.     

Caco-2细胞系及其在药物吸收、代谢中的应用

由于小肠的生理结构适用于药物吸收 ,所以口服给药是最广泛、最方便的给药途径之一 ,因此研究药物在肠道的吸收与代谢就显得十分必要。目前用于药物吸收的实验方法主要有 :在体肠回流法 ,肠襻法 ,分离肠粘膜法、外翻囊法等 [1 ]。由于这些方法存在采用动脉组织及其它一些局限性 ,近年来人们尝试使用人肠细胞培养系统来研究药物在肠道的吸收和代谢 ,以快速筛选口服药物。Caco-2细胞模型被认为是目前最好的体外吸收模型 ,可用于快速评估新药的细胞渗透性、阐明药物转运的途径、评价提高膜通透性的方法、确定被动扩散的药物最合适的理化性质和…     

利用Caco -2细胞模型研究五倍子水提物的降糖机制

目的 建立Caco -2细胞单层模型并探索其在筛选抗糖尿病药物方面的作用,研究五倍子水提物的降糖作用及机制.方法采用酶抑制剂模型研究五倍子水提物的α－糖苷酶抑制作用;用Caco -2细胞模型进一步研究五倍子水提物对肠上皮细胞麦芽糖酶和蔗糖酶活力的影响以及对葡萄糖转运吸收的影响.结果五倍子水提物能抑制酶抑制剂模型和小肠上...     

Caco-2细胞模型对毛萼乙素的摄取与转运

目的研究Caco 2细胞对毛萼乙素（ERB）的摄取和跨膜转运特性。方法采用体外培养的人肠腺癌上皮细胞模型研究Caco 2细胞对ERB的摄取与跨膜转运,考察时间、浓度及温度对Caco 2摄取和转运ERB的影响。采用高效液相色谱法测定ERB含量,计算其表观渗透系数（Papp）。结果Caco 2摄取和转运ERB过程中,A B侧表观渗透系数在45 min前与时间、温度呈正相关,与有效浓度也呈正相关。结论ERB主要以被动扩散方式被小肠上皮细胞吸收并实现跨膜转运。     

Caco-2 monolayers in experimental and theoretical predictions of drug transport

This review examines the use of Caco-2 monolayers in the prediction of intestinal drug absorption. First, the different routes of drug transport in Caco-2 monolayers are compared with those seen in vivo. Second, the prediction of drug absorption in vivo from transport experiments in cell monolayers is discussed for different classes of drugs. Finally, the use of Caco-2 monolayers as a reference model in physico-chemical and theoretical predictions of drug absorption is discussed. We conclude that Caco-2 monolayers can be used to identify drugs with potential absorption problems, and possibly also to select drugs with optimal passive absorption characteristics from series of pharmacologically active molecules generated in drug discovery programs.     

Caco-2 monolayers in experimental and theoretical predictions of drug transport

This review examines the use of Caco-2 monolayers in the prediction of intestinal drug absorption. First, the different routes of drug transport in Caco-2 monolayers are compared with those seen in vivo. Second, the prediction of drug absorption in vivo from transport experiments in cell monolayers is discussed for different classes of drugs. Finally, the use of Caco-2 monolayers as a reference model in physico-chemical and theoretical predictions of drug absorption is discussed. We conclude that Caco-2 monolayers can be used to identify drugs with potential absorption problems, and possibly also to select drugs with optimal passive absorption characteristics from series of pharmacologically active molecules generated in drug discovery programs.     

细胞共培养模型在口服药物吸收研究中的应用

细胞共培养体系能很好地模拟人体小肠生理环境,准确预测药物在肠道内的转运和代谢情况,增强体外细胞模型与整体动物实验研究之间的相关性,近年来在评价口服药物吸收方面发挥着越发重要的作用,已成为新药研发过程中评价药物口服吸收的热点。综述体外模拟肠道环境的细胞共培养模型,并对其应用于口服药物研发的体外评价吸收做出展望。     

Enhancing effect of N-octyl-O-sulfate chitosan on etoposide absorption

P-glycoprotein (P-gp), expressed in the apical membranes of the epithelial cells of the intestine, can reduce the oral bioavailability of a wide range of drugs. Many surfactants/excipients have been demonstrated to potentially increase drug absorption by inhibiting P-gp. The purpose of the present study was to evaluate the effect of N-octyl-O-sulfate chitosan (NOSC) on the absorption of etoposide (VP16), a substrate of P-gp with low water solubility. The rat intestinal circulating perfusion in situ and Caco-2 cell uptake and monolayer membrane penetration in vitro were performed to investigate the enhancing ability of NOSC in comparison with some other P-gp inhibitors. The results indicated that various concentrations of NOSC all increased the intestinal absorption of VP16 in rat jejunum and ileum obviously and there was no significant difference in ileum between the enhancing effects of NOSC and other P-gp inhibitors. The VP16 uptake of Caco-2 cell was increased by NOSC solution with different concentrations. As the NOSC concentration was close to its critical micelle concentration (CMC), the cell uptake of VP16 reached to a maximum value. Both NOSC and verapamil (Ver) enhanced dramatically the transport of VP16 from apical side to basolateral side in Caco-2 cell monolayers. Moreover, they both decreased notably the transport of VP16 from basolateral side to apical side, but this effect of NOSC was weaker than that of Ver. However, transepithelial electrical resistance (TEER) of Caco-2 cell monolayers had no significant change during the study. These studies demonstrated that NOSC had the potential by inhibiting P-gp to improve the absorption of oral drugs which were P-gp substrates.     

Mechanisms of Membrane Transport of Poorly Soluble Drugs: Role of Micelles in Oral Absorption Processes

Micelles formed in the GI tract by bile acid and lecithin play an important role in oral absorption of poorly soluble drugs. In this situation, the drug molecules are present in equilibrium between the free and micellar states. In this study, the relationship between the free drug concentration and the membrane permeability of poorly soluble drugs was examined. Permeability across a Caco‐2 monolayer and a dialysis membrane were measured in a side‐by‐side chamber system. The concentrations of sodium taurocholate (NaTC) and lecithin were varied to allow measurement of membrane permeability at different concentrations of free drugs. For troglitazone, hexylparaben, and heptylparaben, an increase in the NaTC and lecithin concentrations caused the permeability across the Caco‐2 monolayer to decrease slightly, whereas the permeability across the dialysis membrane decreased markedly. In contrast, the changes in permeability of griseofulvin with an increased micelle concentration were similar for the Caco‐2 monolayer and the dialysis membrane. Assuming that the permeability for the dialysis membrane reflects the free drug concentration in the medium, these results suggest that troglitazone and alkylparabens, but not griseofulvin, can partition directly from micelles to Caco‐2 monolayers. This mechanism may contribute to oral absorption of drugs that are poorly soluble in water. © 2009 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 1336–1345, 2010     

Involvement of intestinal permeability in the oral absorption of clarithromycin and telithromycin

The involvement of intestinal permeability in the oral absorption of clarithromycin (CAM), a macrolide antibiotic, and telithromycin (TEL), a ketolide antibiotic, in the presence of efflux transporters was examined. In order independently to examine the intestinal and hepatic availability, CAM and TEL (10 mg/kg) were administered orally, intraportally and intravenously to rats. The intestinal and hepatic availability was calculated from the area under the plasma concentration–time curve (AUC) after administration of CAM and TEL via different routes. The intestinal availabilities of CAM and TEL were lower than their hepatic availabilities. The intestinal availability after oral administration of CAM and TEL increased by 1.3‐ and 1.6‐fold, respectively, after concomitant oral administration of verapamil as a P‐glycoprotein (P‐gp) inhibitor. Further, an in vitro transport experiment was performed using Caco‐2 cell monolayers as a model of intestinal epithelial cells. The apical‐to‐basolateral transport of CAM and TEL through the Caco‐2 cell monolayers was lower than their basolateral‐to‐apical transport. Verapamil and bromosulfophthalein as a multidrug resistance‐associated proteins (MRPs) inhibitor significantly increased the apical‐to‐basolateral transport of CAM and TEL. Thus, the results suggest that oral absorption of CAM and TEL is dependent on intestinal permeability that may be limited by P‐gp and MRPs on the intestinal epithelial cells. Copyright © 2014 John Wiley & Sons, Ltd.     

Permeability Characteristics of Calu-3 Human Bronchial Epithelial Cells: In Vitro - In Vivo Correlation to Predict Lung Absorption in Rats

The goal of this study was to evaluate the permeability characteristics of Calu-3, human bronchial epithelial cells to passive and actively transported drugs and to correlate the data with other in vitro models and rat lung absorption in vivo. Air-interface cultured Calu-3 cells grown on collagen-coated permeable filter supports formed "tight" polarized and well differentiated cell monolayers with apical microvilli and tight-junctional complexes. Within 8-10 days, cell monolayers developed transepithelial electrical resistance (TEER)>1000 ohm cm 2 and potential difference about 11-16 mV. Solute permeability was dependent on lipophilicity, and inversely related to molecular size. Calu-3 cells actively transported amino acids, nucleosides and dipeptide analogs, but not organic anions, organic cations or efflux pump substrates. The permeability characteristics of Calu-3 cells correlated well with primary cultured rabbit tracheal epithelial cells in vitro (r 2 =0.91), and the rate of drug absorption from the rat lung in vivo (r 2 =0.94). The absorption predicted from the regression equation correlated well with observed values. In conclusion, in vitro - in vivo correlation studies indicate that the Calu-3 cell culture model is a potentially useful model to predict absorption of inhalation delivery drug candidates.     

Permeability characteristics of calu-3 human bronchial epithelial cells: in vitro-in vivo correlation to predict lung absorption in rats

The goal of this study was to evaluate the permeability characteristics of Calu-3, human bronchial epithelial cells to passive and actively transported drugs and to correlate the data with other in vitro models and rat lung absorption in vivo. Air-interface cultured Calu-3 cells grown on collagen-coated permeable filter supports formed "tight" polarized and well differentiated cell monolayers with apical microvilli and tight-junctional complexes. Within 8-10 days, cell monolayers developed trans-epithelial electrical resistance (TEER) > 1000 ohm cm2 and potential difference about 11-16 mV. Solute permeability was dependent on lipophilicity, and inversely related to molecular size. Calu-3 cells actively transported amino acids, nucleosides and dipeptide analogs, but not organic anions, organic cations or efflux pump substrates. The permeability characteristics of Calu-3 cells correlated well with primary cultured rabbit tracheal epithelial cells in vitro (r2 = 0.91), and the rate of drug absorption from the rat lung in vivo (r2 = 0.94). The absorption predicted from the regression equation correlated well with observed values. In conclusion, in vitro-in vivo correlation studies indicate that the Calu-3 cell culture model is a potentially useful model to predict absorption of inhalation delivery drug candidates.     

Optimized conditions for prediction of intestinal drug permeability using Caco-2 cells.

The effects of various experimental conditions on in vitro drug permeability to Caco-2 monolayers were investigated to determine the optimized conditions for the prediction of intestinal drug absorption. Concerning the pH of the transport medium in the Caco-2 study, two different pH values, 6.0 and 7.4, were tested for the apical medium with the pH of the basolateral medium fixed to 7.4. The change in the apical pH showed pronounced effects on the permeability of both passively and actively transported drugs. It was found that the transport study under the condition of an apical pH value of 6.0 showed a better prediction of in vivo drug absorption in human. The appropriate conditions for determining the permeability of poorly soluble drugs were also examined. First, the effects of bile acids, surfactant and some agents used for solubilizing drugs on the permeability and transepithelial electrical resistance (TEER) of Caco-2 monolayers were investigated. Taurocholic and cholic acid showed no effects on the permeability of 3H-Dexamethasone (DEX) and TEER at 10 mM concentration, suggesting the possibility of use in the Caco-2 study. Polyethyleneglycol-400 and dimethylsulfoxide reduced the permeability of DEX concentration dependently, whereas ethanol induced no significant changes in the permeability. Furthermore, it was demonstrated that the addition of plasma protein (bovine serum albumin) to the basolateral medium apparently facilitated the transport of poorly soluble drugs with high lipophilicity across Caco-2 monolayers. These findings clearly suggest the importance of considering the physiological conditions of in vivo drug absorption in optimizing the in vitro experimental conditions for transport study using Caco-2 cells, in order to obtain a satisfactory in vitro-in vivo correlation.     

Effect of P-glycoprotein expression levels on the concentration-dependent permeability of drugs to the cell membrane

The purpose of this study is to develop a kinetic model that can predict the in vivo absorption of P-glycoprotein (P-gp) substrates from in vitro data. Apical (AP) to basal (BL) absorptive permeability of typical P-gp substrate drugs including quinidine, verapamil, vinblastine, and digoxin, were measured in several cell monolayers with different levels of P-gp expression, normal, P-gp induced, P-gp highly induced and MDR1-knockdown Caco-2 cells and MDR1-MDCKII cells. In all cell monolayers, AP to BL permeability of P-gp substrates increased when their AP concentration was increased, showing a sigmoid-type relationship to donor (AP) concentrations. At the higher concentration range, permeability reached a maximum value, suggesting saturation of P-gp-mediated efflux, and at the lower concentration range, permeability decreased depending on P-gp expression level. A simple kinetic model was applied to the permeability-concentration curve of each drug to obtain the fundamental parameters for P-gp-mediated transport, K(m(app)) and V(max). Both K(m(app)) and V(max) of each drug were found to show linear correlations with expression level of P-gp. This study clearly demonstrated the possibility to estimate the permeability of P-gp substrate drugs in human intestine from the expression level of P-gp, and thus the possibility to predict oral absorption of those drugs.