呋塞米在Caco-2细胞单层模型中的跨膜转运研究

目的研究呋塞米口服的吸收机制。方法首先通过MTT法考察呋塞米对细胞活性和增殖的影响情况,其次采用Caco-2细胞单层模型研究呋塞米的跨膜转运机制。结果呋塞米浓度≤100μmol/L对Caco-2细胞活性和增殖无影响;25,50,100μmol/L的呋塞米从AP侧到BL侧转运的表观渗透系数分别为0.364,0.347,0.345×10^-6cm/s,外排率Pratio分别为1.74,1.7和1.67;加入维拉帕米前后的外排率Pratio分别为1.78和1.13,有显著性差异。结论呋塞米以被动扩散为主要的转运方式,存在可能由P-糖蛋白介导的主动转运。     

熊果酸在Caco-2细胞单层模型中的跨膜转运

熊果酸(Ursolic acid, UA),又名乌索酸,乌苏酸,属a-香树脂醇(a-amyri)型五环三萜类化合物.在自然界分布非常广泛,据目前所知,至少存在于26个科70多种天然植物中[1].大量的研究表明,UA具有广泛的药理作用和重要的生物活性,尤其在抗炎、护肝、抗肿瘤以及机体免疫调节等方面已经显现出令人关注的药理特性[2,3].体内药代动力学研究表明, UA的生物利用度低[4],口服吸收情况较差,而且其在体内吸收转运的方式和机制也并不清楚.Caco-2细胞系来源于人结肠类腺癌细胞,其结构和生化作用类似于人小肠上皮细胞,含有与小肠刷状缘上皮相关的转运系统以及一     

阿立哌唑在Caco-2细胞单层模型中的跨膜转运

本文研究了阿立哌唑（aripiprazole）在Caco-2细胞模型中的跨膜转运特征。一种体外培养的人小肠上皮细胞模型 —— Caco-2细胞模型应用于阿立哌唑的跨膜转运研究。评价了时间、供给液浓度、pH值、温度及P-糖蛋白抑制剂对阿立哌唑跨膜转运的影响。采用高效液相色谱法检测药物浓度。结果表明阿立哌唑主要通过被动扩散的机制转运,同时兼有载体介导转运。阿立哌唑的转运量与时间、pH值、温度成正相关。表观渗透系数P_app值随供给液浓度升高而增大,10 μg·mL^-1时趋向饱和,之后随阿立哌唑浓度的增加而逐渐减小。P-糖蛋白抑制剂环孢菌素-A显著增加阿立哌唑的跨膜转运。     

金丝桃苷在Caco-2细胞模型中的跨膜转运方式

目的研究金丝桃苷在Caco-2细胞模型中的吸收机制。方法用Caco-2细胞单层模型研究金丝桃苷的双向转运,考察pn、药物质量浓度、方向、温度、抑制剂对金丝桃苷细胞转运的影响。采用HPLC法检测金丝桃苷的含量,计算其表观渗透系数(P_app)。结果金丝桃苷的细胞转运P_app。具有pH依赖性。金丝桃苷肠腔（A）侧→基底（B）侧P_app>B→A,并且随着金丝桃苷质量浓度的增大而减小,具有浓度依赖性。P-gp抑制剂维拉帕米增加金丝桃苷的细胞正向转运P_app,降低了其逆向转运P_app。金丝桃苷较高浓度时,MRPl抑制剂吲哚美辛和ATP抑制剂叠氮化钠显著降低了金丝桃苷的转运量。结论金丝桃苷在Caco-2细胞单层模型中的转运具有pH依赖性和浓度依赖性,是以主动转运为主,被动扩散为辅,同时涉及外排蛋白作用的转运方式。     

Caco-2细胞对酸枣仁皂苷A的跨膜转运

目的研究酸枣仁皂苷A（Jujuboside A,JuA）在Caco-2细胞的跨膜转运特性。方法采用体外培养的Caco-2细胞单层模型,考察时间、介质pH值、药物浓度、抑制剂对JuA在Caco-2细胞上转运的影响。结果 Caco-2细胞转运JuA呈时间及浓度依赖性;在pH为5.0～8.0范围内,Caco-2细胞对JuA的转运不受pH值的影响;P-糖蛋白（P-glycoprotein,P-gp）抑制剂维拉帕米（Verapamil,Ver）对Caco-2细胞转运JuA无影响;线粒体呼吸链复合体Ⅳ抑制剂叠氮化钠（Sodium azide）对Caco-2细胞转运JuA有抑制作用;JuA的AP-BL侧的Papp与BL-AP侧的Papp的两组均数比较无统计学意义。结论 JuA不是P-gp的底物,其跨膜转运是被动转运与主动转运共同参与的过程。     

硅质体的形状对其跨Caco-2细胞单层转运的影响

本文旨在构建球形和盘状两种不同形状的硅质体,以研究纳米载体的形状对其细胞摄取及跨膜能力的影响。经卤代、亲核加成及酰化反应合成硅质体复合脂质(cerasome-forming lipid, CFL),并利用质谱和核磁共振氢谱进行鉴定。将CFL与短链脂材1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC)通过薄膜水化法制备有机-无机杂化的纳米盘(nanodisc,简称纳米盘),并使用CFL制备球形硅质体(nanosphere,简称硅质体)。用激光粒度仪测定硅质体和纳米盘的粒径及电位,透射电镜观察其形状。以人源结肠癌Caco-2细胞为模型,采用激光共聚焦显微镜定性考察形状对纳米载体在细胞上摄取和转运的影响,采用高效液相色谱法定量考察形状对其跨膜量的影响。结果表明:制得的硅质体及纳米盘粒径相近,均约为110 nm,电位约为-25 mV,在电镜下形状规则均一。在20 min内,纳米盘的入胞速率显著快于硅质体,进一步在Caco-2细胞单层模型上的研究结果表明,摄取更快的纳米盘在细胞单层中累积量更少,即更快地被转运出胞,在2 h内纳米盘的跨膜量均高于硅质...     

肠道转运Caco-2细胞单层模型的建立及验证评价

目的建立Caco-2细胞单层模型用于药物转运研究。方法按照常规的细胞培养方法,将Caco-2细胞接种到Millicell小室内(接种密度1×10⁶个·mL^-1),培养21 d。定期用细胞电位仪监测跨上皮细胞电阻（TEER）,评价细胞单层的紧密性与完整性;通过荧光黄转运实验检查Caco-2细胞单层模型细胞旁路转运通透性;通过普萘洛尔转运实验验证Caco-2细胞单层模型跨细胞被动转运通透性。结果培养21 d后,TEER值达到（981±123）Ω·cm²,荧光黄和普萘洛尔的表观通透系数分别为0.33×10及16.7×10^-6cm·s^-1。结论本研究建立的Caco-2细胞单层模型紧密、完整,具有良好通透性,可用于药物转运研究。     

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。     

牡荆素鼠李糖苷在Caco-2细胞模型中的跨膜转运研究

目的 研究牡荆素鼠李糖苷(RHV)在Caco-2细胞模型中的跨膜转运机理.方法 采用Caco-2细胞模型,考察不同浓度、不同吸收促进剂(十二烷基硫酸钠、牛胆盐)对RHV跨膜转运的影响.结果 RHV从肠腔侧到基底侧的转运与从基底侧到肠腔侧的转运相似,前者表观渗透系数随浓度的增大逐渐降低,但差异不具有统计学意义(P>0.05).与对照组比较,加入吸收促进剂后,其表观渗透系数增大.结论 RHV在Caco-2细胞模型中主要表现为被动转运,十二烷基硫酸钠和牛胆盐都能增大RHV从肠腔侧到基底膜侧的转运量.     

布洛芬在Caco-2细胞模型中的转运行为考察

采用Caco-2细胞单层模型考察了布洛芬的吸收机制.用HPLC法测定了磷酸盐缓冲液中布洛芬的转运量.结果显示,布洛芬的转运量受培养时间、浓度和P-糖蛋白抑制剂维拉帕米的影响,其表观渗透系数为1×10-6～7×10-6cm/s,且双向转运的表观渗透性存在方向性差异.这提示布洛芬在Caco-2细胞模型中以主动转运和被动扩散两种机制吸收,且存在P-糖蛋白介导的外排机制.     

Profound Effect of Plasma Protein Binding on the Polarized Transport of Furosemide and Verapamil in the Caco-2 Model

Pharmaceutical Research -     

蜕皮甾酮在Caco-2细胞模型中的摄取和跨膜转运研究

目的以Caco-2细胞单层模型,首次研究了蜕皮甾酮的口服吸收与转运特性。方法采用普通Caco-2细胞模型、表达活性CYP3A4酶的Caco-2细胞模型,分别从AP→BL方向和BL→AP方向研究蜕皮甾酮的摄取和跨膜转运规律。结果蜕皮甾酮在2种模型中的表观渗透系数(Papp)在0.1×10-6～1×10-6cm.s-1之间,药物吸收情况为1%～10%;在4 h的实验过程中,4种浓度蜕皮甾酮的ER值均小于1.5。结论研究表明,蜕皮甾酮主要以被动扩散的方式被细胞摄取和转运,其跨膜转运特性未受到CYP3A4-介导机制的影响。     

Transport of levovirin prodrugs in the human intestinal Caco-2 cell line

The transport of 10 amino acid ester prodrugs of levovirin (LVV) was investigated in the human intestinal Caco-2 cell line in order to overcome the poor oral bioavailability of LVV, an investigational drug for the treatment of hepatitis C infection. The prodrugs were designed to improve the permeability of LVV across the intestinal epithelium by targeting the di/tri-peptide carrier, PepT1. Caco-2 cell monolayers were employed to study the transport and hydrolysis properties of the prodrugs. Among all mono amino acid ester prodrugs studied, the LVV-5'-(L)-valine prodrug (R1518) exhibited the maximum increase (48-fold) in permeability with nearly complete conversion to LVV within 1 h. Di-amino acid esters did not offer significant enhancement in permeability comparing with mono amino acid esters and exhibited slower conversion to LVV in Caco2 cell monolayers. Pharmacokinetic screening studies of the prodrugs in rats yielded the highest fold increase (6.9-fold) of AUC with R1518 and in general displayed a similar trend to that observed in increases of permeability in Caco-2 cells. Mechanisms involved in the Caco-2 cell transport of R1518 were also investigated. Results of bi-directional transport studies support the involvement of carrier-mediated transport mechanisms for R1518, but not for the LVV-5'-(D)-valine prodrug or LVV. Moreover, the permeability of R1518 was found to be proton dependent. PepT1-mediated transport of R1518 was supported by results of competitive transport studies of R1518 with the PepT1 substrates enalapril, Gly-Sar, valganciclovir, and cephalexin. R1518 was also found to inhibit the permeability of valganciclovir and cephalexin. These results suggest that R1518 is a PepT1 substrate as well as an inhibitor.     

蛇床子素及其制剂在Caco-2细胞模型中转运机制的研究

I摘要】目的：研究蛇床子素及其制剂在Caco-2细胞模型中的摄取、转运机制。方法：建立Caco-2细胞单层模型,研究蛇床子素、蛇床予素β-环糊精包合物及其包合物分散片的摄取和跨膜转运,考察其时间、温度、浓度、吸收促进剂和抑制剂对药物摄取及跨膜吸收的影响,并比较原料药与制剂吸收过程的差异。结果：Caco-2细胞对蛇床子素及其制剂溶液的摄取与时间、温度、浓度均呈正相关,p-糖蛋白抑制剂（CyA）与能量抑制剂（NaN3）对摄取无显著性影响,其摄取量的大小依次为分散片〉包合物〉原料药;转运实验中,随浓度和温度的增加,蛇床子素及其制刑的溶液在Caco-2细胞中的转运量均增加,而只r与Rt比值无明显变化,P-糖蛋白抑制剂（CyA）、能量抑制剂（NaN,）、细胞内吞抑制剂．氧化苯砷（oxophenylarsine）7L胞旁路转运促进剂一去氧胆酸钠（sodiumdeoxycholate,SDCh）对蛇床子素的转运无影响,而去氧胆酸钠对包合物和分散片的转运有明显的影响,3种制刑AP—BL方向上的Papp为分散片〉包合物〉原料药。结论：蛇床子素主要以被动扩散的方式被吸收,包合物和分散片中的药物以被动转运为主,少部分以细胞旁路转运途径被细胞吸收;难溶性药物经包合物可促进其吸收,制剂辅料对药物的吸收有一定的促进作用。     

Transport properties of bovine and reindeer beta-lactoglobulin in the Caco-2 cell model

Beta-lactoglobulin (betaLG) is a protein that binds ligands like fatty acids and retinol into the hydrophobic pocket. Our purpose was to study bovine and reindeer betaLG as transporter molecules and compare their transport properties across Caco-2 cell membrane. The reindeer betaLG has more valuable binder characteristics than bovine betaLG because it has only one genetic phenotype and it seems to exhibit better immunological properties. The permeation of betaLG in Caco-2 cells was evaluated by immunoblotting, and the permeation of the model substances retinol, palmitic acid and cholesterol with and without betaLG was determined using [(3)H]-labelled ligands. Both bovine and reindeer betaLG were able to pass across a Caco-2 cell monolayer similarly. Unbound and betaLG-bound [(3)H]retinol and [(3)H]palmitic acid were equally transported across the Caco-2 cell layer, whereas [(3)H]cholesterol could not pass across Caco-2 cells with or without betaLG at any of the studied circumstances. Thus, the bovine and reindeer milk betaLG is not a suitable protein to enhance transport of ligands across the Caco-2 cell membrane, used for predicting intestinal absorption.     

坎地沙坦与坎地沙坦酯在Caco-2细胞模型中的转运特性

目的 研究坎地沙坦(Cand)与坎地沙坦酯(Cil)在Caco-2细胞中的跨膜转运特征.方法 采用Caco-2细胞单层膜模型来考察药物的浓度、介质pH与P-gp抑制剂维拉帕米对Cand与Cil跨膜转运的影响,并比较两者双向跨膜转运的差异.结果 两者的吸收转运具有pH依赖性,分泌转运具有浓度依赖性,其分泌(BL-AP)方向转运均快于吸收(AP-BL)方向转运,且Cil的AP-BL方向转运比Cand快;在P-gp抑制剂维拉帕米存在下,两者的转运外排率显著下降(P<0.01).结论 Cil容易通过Caco-2细胞的单层膜,且外排蛋白参与了Cand与Cil的跨膜转运.     

Transport of chlorpromazine in the Caco-2 cell permeability assay: a kinetic study

The intestinal transport of compounds can be measured in vitro with Caco-2 cell monolayers. We took a closer look at the exposure and fate of a chemical in the Caco-2 cell assay, including the effect of protein binding. Transport of chlorpromazine (CPZ) was measured in the absorptive and secretory direction, with and without albumin basolaterally. Samples were taken from medium, cells, and well plastic. For the secretory transport experiments with albumin, the free CPZ concentration at the start of the experiment was measured by negligible depletion-solid phase microextraction (nd-SPME). Recovery of CPZ from the medium was low, especially in the absorptive transport direction. CPZ was found in the cells (≤20%) and bound to the well plastic (≤25%), and 94% of CPZ was bound to albumin. An initial lag phase was observed, which was likely caused by partitioning of CPZ between the donor concentration and the Caco-2 cells; after 20 min, transport of CPZ to the receiver compartment was linear. The low recovery and the test compound found both inside the Caco-2 cells and bound to the well plastic complicate the calculation of the fraction transported and render reliable estimates of permeability constants impossible. For a chemical like chlorpromazine, which is hydrophobic in its neutral form, but in general also for more lipophilic compounds, the Caco-2 cell assay might not be straightforward, and a more detailed study into the fate and exposure of the test compound might be needed to arrive at meaningful data for transport and permeability.