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??OBJECTIVE To study the effect of levetiracetam on the absorption of methotrexate in rats and related mechanisms, and provide reference for clinical rational use of two drugs. METHODS ??Pharmacokinetic study: Sprague Dawley (SD) Rats (250??20)g were randomly divided into control group and experimental group, 5 rats in each group, administered by intragastric administration. At the design time point, blood was taken from the fundus venous plexus and centrifuged. Supernatant plasma for detection. ??The intestine experiment was performed in vitro: the rat 10 cm jejunum was taken and the intestinal segment was gently inverted with a capillary tube, and the intestinal anal side was ligated. After the 1 mL KRB buffer was added to the inverted intestinal lumen, the intestinal sac was placed vertically into the drug-containing solution. ??Caco-2 Cells uptake experiments: The Caco-2 cells were inoculated in a 24-well plate for 15 days and then subjected to an uptake experiment. After the incubation for 30 minutes, the cells were stopped for uptake and washed, and the cells were lysed for the detection of methotrexate and protein. Calculate the amount of drug intake. RESULTS ??The main pharmacokinetic parameters of control group and experimental group were as follows: ??_max(ng??mL^-1): 28.6??3.04??54.33??13.97; t_max(min): 50??8.32??70??7.32; AUC_0-t(ng??min??mL^-1): 8 230??2 274?? 15 003??3 359; AUC_0-??(ng??min??mL^-1): 8 450??2 125??15 108??3 371; CL(mL^-1??min??kg^-1): 161.8??27.6?? 90.43??13.76. In the experimental group, the ??_max, t_max, AUC_0-t and AUC_0-?? values of methotrexate increased, and the CL value descreased. The difference was statistically significant. ??Compared with the control group, levetiracetam in the experimental group significantly increased the drug concentration of the methotrexate on the serosal side of the intestine, and its effect was time-dependent. ??Verapamil, digoxin and levetiracetam increased the uptake of methotrexate in the Caco-2 cells, and the effect of levetiracetam was dose-dependent. CONCLUSION When methotrexate and levetiracetam were combined, the drug interactions mediated by the efflux transporter P glycoprotein in the intestinal tract. Methotrexate reduces efflux in the body, increases absorption, and increases plasma concentration. It is suggested that the dose of methotrexate should be adjusted when the combination of methotrexate and levetiracetam, and blood concentration should be monitored if necessary.     

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??OBJECTIVE To study the in situ small intestinal absorption mechanism of ZYS-01 in rats and discuss its absorption mechanism.METHODS Single pass intestinal perfusion model was established, intestinal perfusate concentration of ZYS-01 was measured by HPLC, using the gravimetric method corrected the perfusate volume, absorptions of different dose groups of ZYS-01 in different segments and the effect of P-glycoprotein(P-gp) inhibitors on the absorption of ZYS-01 were investigated. RESULTS ZYS-01 was absorpted in the whole small intestinal segments, its absorption rate was related to intestinal segments and perfusate concentrations, P_eff was more than 0.2??10^-4 cm??s^-1. P-gp inhibitors could obviously increase the absorption of ZYS-01 in different intestinal segments. CONCLUSION ZYS-01 is high permeable drug, it can be absorpted in the whole small intestinal segments, duodenum has the fastest absorption rate. the absorption is effected by different concentrations, low concentration has the fastest absorption rate, with the increasing of concentration,the absorption rate decreased gradually . The absorption mechanism of ZYS-01 is active transport. ZYS-01 may be a substrate for P-gp.     

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??OBJECTIVE To establish a method for determination of the total content of andrographolide sulfonate, transport of two kinds of main components in the injection in Calu-3 and Caco-2 cell model, can be applied to the assessment of lung and oral administration to the safety and effectiveness of drugs. METHODS Screening of safe concentration of drugs by cytotoxicity test. Injection of andrographolide total sulfonate in safe concentrationwere applied to Calu-3 and Caco-2 cell models. Samples were taken for a certain period of time to determine the influence of concentration and time on the transport, and the apparent osmotic coefficients of the principal components were calculated. RESULTS When the concentration of the drug was less than 500 ??g??mL^-1, the survival rate of Calu-3 and Caco-2 cells was close to 100%.The established cell model showed excellent compactness and integrity.In the Calu-3 cell model, the apparent permeability coefficients of andrographolide sulfate C and 9-dehydro-17-hydro-andrographolide were 1??10^-5 orders of magnitude.In the Caco-2 cell model, both were 1??10^-6 orders of magnitude.On two cell models, the efflux ratios were less than 2. CONCLUSION The principal component of andrographolide total sulfonate injection is not the substrate for P glycoproteins, it has moderate absorption in the intestine, and has good absorption in the respiratory tract. Pulmonary administration is safer and more effective.     

单向灌流法评价芦荟大黄素大鼠体内肠吸收的研究

目的:研究芦荟大黄素在大鼠不同肠段的吸收特性,以及P-糖蛋白(P-gp)和多药耐药相关蛋白(MRP2)对芦荟大黄素肠吸收的影响.方法:采用大鼠在体单向肠灌流实验,用HPLC测定灌流液中芦荟大黄素的含量,计算芦荟大黄素在大鼠各肠段及加入P-gp抑制剂和MRP2抑制剂后的吸收速率常数(Ka)和表观吸收系数(Papp).结果:各实验组的Ka,Papp从大到小依次为十二指肠组、空肠组、结肠组和回肠组,十二指肠组与回肠组比较有明显增加(P＜0.05),其他各组之间无统计学差异;含P-gp抑制剂组与不含抑制剂组比较,Ka,Papp均有极显著的增加(P＜0.01).含MRP2抑制剂高、中浓度组与不含抑制剂组比较,Ka,Papp均显著增加(P＜0.05).结论:芦荟大黄素在十二指肠段吸收相对较好,在回肠段的吸收相对较差;P-gp和MRP2的抑制剂均可促进芦荟大黄素的肠吸收.     

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??OBJECTIVE Investigate different intestinal segments absorption of salvianolic acids and compatibility of different concentration of sodium caprate in rats. METHODS Using single-pass intestinal perfusion model, three concentrations of lithospermic acid, rosmarinic acid and salvianolic acid B was determined by HPLC, and the intestinal absorption parameters of K_a and P_app was calculated. RESULTS When salvianolic acids concentrion was 800 ??g??mL^-1 salvianolic acids concentration, absorption of lithospermic acid of various intestinal segmentsduodenum??jejunum??ileum; absorption of rosmarinic acidileum??jejunum??duodenum; absorption of salvianolic acid Bileum??jejunum??duodenum. After salvianolic acids combined with different concentrations of sodium caprate, low concentration of sodium caprate slightly inhibited the lithospermic acid and salvianolic acid B uptake, middle and high concentration sodium caprate were able to better promote salvianolic acids intestinal absorption. CONCLUSION Sodium caprate can promote intestinal absorption of salvianolic acids. With sodium caprate concentration increasing, absorption enhancing effect is more significant.     

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??OBJECTIVE To study the absorption characteristics of cajanonic acid A using in vitro Caco-2 cell model. METHODS The toxicity of cajanonic acid A on Caco-2 cells was investigated by MTS, the bi-directional transport of cajanonic acid A from AP??BL and BL??AP was investigated, the cumulative transport and apparent permeability(P_app) were calculated,and the relationships between the transport amount and concentration, time, and the P-glycoprotein inhibitor verapamil were further studied. RESULTS The transport amount of cajanonic acid A increased with time and concentration, the P_app from apical(AP) side to basolateral(BL) side was 2.01??10^-6-3.95??10^-6 cms^-1, and the P_app from basolateral(BL) side to apical(AP) side was 2.51??10^-6-6.03??10^-6 cms^-1. CONCLUSION The current data suggests that the absorption of cajanonic acid A in the Caco-2 cell model is not a simple passive diffusion, the efflux ratio indicates that the efflux protein of P-gp may be involved, and the P_app suggests that the oral absorption is medium.     

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??OBJECTIVE To clarify the effect of total glucosides from paeony(PTG) on irritable bowel syndrome (IBS), and to explore the molecular mechanism of PTG on alleviating diarrhea symptoms and abdominal pain.METHODS The diarrhea model was conducted by exposing rat to restraint stress stimulation and bellyache model was conducted by subcutaneous injection of neostigmine to mice. Based on these two models, the curative effect of PTG on IBS was investigated. To investigate the regulative effects of PTG on Caco-2 cells, the Caco-2 monolayer cell model with barrier dysfunction was established by trypsin stimulation, and the inflammatory Caco-2 cell model was established by interleukin-1?? (IL-1??) stimulation.RESULTS PTG could significantly reduce the frequency of defecation in diarrhea rat model (P<0.05) and relieve abnormal bowel movements in bellyache mice model (P<0.05). After PTG treatment, the TEER value of Caco-2 monolayer was significantly increased (P<0.01), the transmittance of fluorescence yellow was significantly decreased (P<0.001) and the expression of tight junction (ZO-1)protein was notably up-regulated (P<0.001). In addition, the gene and protein expression of nuclear factor profilin kappa B(I??B??)in inflammatory Caco-2 cell model was significantly improved (P<0.001) after PTG treatment.CONCLUSION PTG significantly ameliorates IBS symptoms by protecting the barrier function of Caco-2 cell monolayer and relieving inflammation of Caco-2 cells.     

白桦脂酸在大鼠体肠吸收动力学的研究

目的:建立同时测定肠循环液中白桦脂酸和酚红浓度的HPLC-DAD法,并探讨白桦脂酸在大鼠各肠段的吸收动力学特征及不同药物浓度对吸收的影响。方法:采用大鼠在体肠吸收实验模型,并考察吸收部位、药物浓度和pH对药物吸收的影响。结果:在75～125 mg.L-1白桦脂酸的吸收速率与质量浓度呈线性关系,Ka基本保持不变;各肠段的吸收速率无显著性差异,十二指肠、空肠、回肠和结肠的Ka分别为(0.151±0.004 9),(0.159±0.005 6),(0.156±0.008 3),(0.149±0.004 1)h-1。结论:白桦脂酸在小肠中吸收良好,没有特定吸收部位;不同浓度对白桦脂酸在大鼠全肠道的吸收无显著影响,其在肠道的吸收呈一级吸收动力学特征,吸收机制为被动扩散。白桦脂酸是难溶性药物,可以通过增加药物的溶出度,进而提高药物的生物利用度。     

补骨脂素在Caco-2细胞模型中的吸收特性研究

 目的 研究补骨脂素在Caco-2细胞模型中的吸收特性,为设计合理的给药方式提供依据。方法 利用MTT实验筛选出 补骨脂素在Caco-2细胞中的安全浓度,然后用Caco-2细胞单层模型研究补骨脂素的双向转运,采用高效液相色谱法检测药物 浓度,计算其表观渗透系数,考察时间、药物浓度对补骨脂素吸收的影响。结果 补骨脂素在Caco-2细胞模型中的转运中对 应时间点表观渗透系数值(P_app)A→B约等于B→A,随时间增加P_app逐渐下降,而在所测浓度范围内P_app值基本保持恒定。 结论 补骨脂素在Caco-2细胞模型中的吸收机制主要是被动转运。     

阿魏酸在Caco-2细胞模型的通透性及其在大鼠体内吸收特性研究

目的 研究阿魏酸在大鼠体内的绝对生物利用度(Fabs)及其吸收特点.方法 建立人源结肠腺癌细胞系Caeo-2单层细胞模型,LC-MS/MS法分析阿魏酸由绒毛面(AP侧)到基底面(BL侧)和由BL侧到AP侧两个方向的转运过程;用大鼠原位肠肝血管灌流模型研究阿魏酸在肠道的吸收率;通过测定大鼠ig和iv阿魏酸后的血药浓度计算其Fabs.结果 阿魏酸的表观渗透系数(Papp)分别为Papp AP→BL:(10.24±1.58)×10 6cm/s,Papp BL→AP:(11.25±1.45)×10-6 cm/s;在肠肝血管灌流模型中的吸收率为59.00％;在大鼠体内的Fabs为64.91％.结论 LC-MS/MS定量分析法灵敏、简单、专属性强;阿魏酸在Caco-2细胞具有良好的转运,在肠肝血管灌流模型中吸收速度快,主要吸收部位为小肠,阿魏酸ig给药后在大鼠体内达峰时间短,吸收、分布、消除较快.