Intestinal permeability of metformin using single-pass intestinal perfusion in rats

AIM： To characterize the intestinal transport and mechanism of metformin in rats and to investigate whether or not metformin is a substrate for P-glycoprotein （P-gp）. METHODS： The effective intestinal permeability of metformin was investigated using single-pass intestinal perfusion （SPIP） technique in male Waster rats. SPIP was performed in three isolated intestinal segments （duodenum, jejunum and ileum） at the same concentration of metformin （50 μg/mL） to test if the intestinal transport of metformin exhibited site- dependent changes, and in a same isolated intestinal segment （duodenal segment） at three different concentrations of metformin （10, 50, 200 μg/mL） to test if the intestinal transport of metformin exhibited concentration-dependent changes. Besides, P-gp inhibitor verapamil （400 μg/mL） was co-perfused with metformin （50 μg/mL） in the duodenum segment to find out if the intestinal absorption of metformin was affected by P-gp exiting along the gastrointestinal track. Stability studies were conducted to ensure that the loss of metformin could be attributed to intestinal absorption. RESULTS： The effective permeability values （Peff） of metformin in the jejunum and ileum at 50μg/mL were significantly lower than those in the duodenum at the same concentration. Besides, Peff values in the duodenum at high concentration （200 μg/mL） were found to be significantly lower than those at low and medium concentrations （10 and 50 μg/mL）. Moreover the coperfusion with verapamil did not increase the Peff value of metformin at 50 μg/mL in the duodenum.CONCLUSION： Metformin could be absorbed from the whole intestine, with the main absorption site at duodenum. This concentration-dependent permeability behavior in the duodenum indicates that metformin is transported by both passive and active carrier-mediated saturable mechanism. The Peff value can not be increased by co-perfusion with verapamil, indicating that absorption of metformin is not efficiently transported by P-gp in the gut wall. Furthermore metformin is neither a substrate nor an inducer of P-gp. Based on the Peff values obtained in the present study and using established relationships, the human fraction dose absorbed for metformin is estimated to be 74%-90% along human intestine.

The preparation of Garcinia Glycosides solid dispersion and intestinal absorption by rat in situ single pass intestinal perfusion

Garcinia Glycosides is a candidate drug obtained by structural modification of Gambogic Acid (GA), which was acquired through High Throughput Screening(HTS). As Garcinia Glycosides is an effective but insoluble anti-tumor drug, the aim of this study was to obtain a solid dispersion form Garcinia Glycosides by using solvent-melt method so that improve the solubility and dissolution rate. The solid dispersion was characterized by High Performance Liquid Chromatography (HPLC), infrared spectroscopy and evaluated the intestinal absorption of the drug by rat in situ single pass intestinal perfusion. The results showed the increase of solubility, dissolution velocity and absorption compared to other forms. This indicated that solid dispersion could greatly improve the relative bioavailability of Garcinia Glycosides in vivo.

Impact of machine perfusion of the liver on post-transplant biliary complications: A systematic review

AIM To review the clinical impact of machine perfusion(MP) of the liver on biliary complications post-transplantation, particularly ischaemic-type biliary lesions(ITBL). METHODS This systematic review was performed in accordance with the Preferred Reporting Systematic Reviews and MetaAnalysis(PRISMA) protocol. The following databases were searched: PubMed, MEDLINE and Scopus. The keyword "liver transplantation" was used in combination with the free term "machine perfusion". Clinical studies reporting results of transplantation of donor human livers following ex situ or in situ MP were analysed. Details relating to donor characteristics, recipients, technique of MP performed and post-operative biliary complications(ITBL, bile leak and anastomotic strictures) were critically analysed.RESULTS Fifteen articles were considered to fit the criteria for this review. Ex situ normothermic MP was used in 6 studies, ex situ hypothermic MP in 5 studies and the other 4 studies investigated in situ normothermic regional perfusion(NRP) and controlled oxygenated rewarming. MP techniques which have per se the potential to alleviate ischaemia-reperfusion injury: Such as hypothermic MP and NRP, have also reported lower rates of ITBL. Other biliary complications, such as biliary leak and anastomotic biliary strictures, are reported with similar incidences with all MP techniques. There is currently less clinical evidence available to support normothermic MP as a mitigator of biliary complications following liver transplantation. On the other hand, restoration of organ to full metabolism during normothermic MP allows assessment of hepatobiliary function before transplantation, although universally accepted criteria have yet to be validated.CONCLUSION MP of the liver has the potential to have a positive impact on post-transplant biliary complications, specifically ITBL, and expand extended criteria donor livers utilisation.

异功散中人参皂苷类成分在脾虚大鼠模型肠吸收动力学变化及其陈皮的影响

目的基于脾虚大鼠模型探讨异功散中陈皮对人参皂苷类成分肠吸收变化的影响及其影响是否与P-gp蛋白外排作用有关。方法分组设计加入P-gp蛋白激动剂利福平与抑制剂维拉帕米,将36只SD大鼠随机分为空白对照组(6只)与模型组(30只),予以皮下注射利血平建立脾虚模型后将模型组分为异功散组(Y组)、去陈皮异功散组(Y-C组)、异功散利福平组(Y+R组)、去陈皮异功散利福平组(Y-C+R组)、去陈皮异功散维拉帕米组(Y-C+V组),以人参皂苷Rb1、人参皂苷Re及人参皂苷Rg1为指标成分,进行在体单向肠灌流实验,采用HPLC-MS测定指标成分含量并计算肠吸收动力学参数有效渗透系数(P_(eff))与吸收速率常数(K_(a))。结果与Y组相比,Y-C组中人参皂苷Rb1和人参皂苷Re在多个灌流时段的P_(eff)显著降低,Y+R组中人参皂苷Rb1、人参皂苷Re及人参皂苷Rg1的P_(eff)和K_(a)在多个灌流时段降低,表明陈皮促进人参皂苷Rb1和人参皂苷Re肠吸收且该作用与P-gp蛋白活性有关,但未能影响人参皂苷Rg1的肠吸收;与Y-C组相比,Y-C+V组中P-gp蛋白抑制剂维拉帕米使人参皂苷Rb1和人参皂苷Re在多个灌流时段P_(eff)显著升高,而Y-C+R组中P-gp蛋白激动剂利福平使人参皂苷Rb1、人参皂苷Re及人参皂苷Rg1的P_(eff)和K_(a)在多个灌流时段显著降低,说明无陈皮干预下,人参皂苷Rb1、人参皂苷Re及人参皂苷Rg1也可能是P-gp蛋白的底物。结论异功散中陈皮通过发挥抑制P-gp蛋白活性的类维拉帕米作用来促进人参皂苷Rb1和人参皂苷Re肠吸收。

Absorption characteristics of the total alkaloids from Mahonia bealei in an in situ single-pass intestinal perfusion assay

AIM: To investigate the absorption characteristics of the total alkaloids from Mahoniae Caulis(TAMC) through the administration of monterpene absorption enhancers or protein inhibitors. METHOD: The absorption behavior was investigated in an in situ single-pass intestinal perfusion(SPIP) assay in rats. RESULTS: The intestinal absorption of TAMC was much more than that of a single compound or a mixture of compounds(jatrorrhizine, palmatine, and berberine). Promotion of absorption by the bicyclic monoterpenoids(borneol or camphor) was higher than by the monocyclic monoterpenes(menthol or menthone), and promotion by compounds with a hydroxyl group(borneol or menthol) was higher than those with a carbonyl group(camphor or menthone). The apparent permeability coefficient(Papp) of TAMC was increased to 1.8-fold by verapamil, while it was reduced to one half by thiamine. The absorption rate constant(Ka) and Papp of TAMC were unchanged by probenecid and pantoprazole. CONCLUSION: The intestinal absorption characteristics of TAMC might be passive transport, and the intestinum tenue was the best absorptive site. In addition, TAMC might be likely a substrate of P-glycoprotein(P-gp) and organic cation transporters(OCT), rather than multidrug resistance protein(MRP) and breast cancer resistance protein(BCRP). Compared with a single compound and a mixture of compounds, TAMC was able to be absorbed in the blood circulation effectively.

基于在体单向肠灌流模型探究去氢骆驼蓬碱衍生物HM-Y-A的肠吸收特性

目的考察去氢骆驼蓬碱衍生物(HM-Y-A)在小肠不同肠段、不同条件下的吸收特性,探究HM-Y-A的吸收机制。方法采用大鼠在体单向肠灌流模型结合HPLC测定法,考察不同肠段、不同药物浓度、不同pH值及P-糖蛋白抑制剂对HM-Y-A吸收参数(K_(a)和P_(app))的影响。结果HM-Y-A在小肠各段均有吸收,最佳吸收肠段是十二指肠和空肠;随着药物浓度升高,吸收参数K_(a)和P_(app)不断降低,低浓度与中、高浓度间差异具有统计学意义(P<0.05);在pH 6.4和7.4时K_(a)和P_(app)显著增高(P<0.05);加入P-糖蛋白抑制剂前后,吸收参数差异无统计学意义。结论HM-Y-A在小肠全段均有吸收,在十二指肠和空肠吸收较好;吸收机制可能以主动吸收或促进扩散为主;药物在偏碱性条件下吸收较好;HM-Y-A可能不是P-gp的底物。

壳聚糖及其衍生物包覆脂质体对胰岛素肠道吸收的影响

目的考察壳聚糖及其衍生物包覆脂质体对胰岛素肠道吸收的影响。方法采用逆相蒸发制备胰岛素脂质体;采用在体肠灌流法研究壳聚糖及其衍生物包覆胰岛素脂质体的肠道吸收;用酶-苯酚法测定血糖值;用放射免疫法测定血清和肠组织中胰岛素含量。结果壳聚糖(CH)、壳聚糖-EDTA 轭合物(CEC)包覆胰岛素脂质体和CH-CEC 双层包覆胰岛素脂质体的最佳吸收部位均集中在十二指肠,胰岛素溶液的最佳吸收部位在结肠,而未包覆胰岛素脂质体和 N-三甲基壳聚糖盐酸盐(TMC)包覆胰岛素脂质体的最佳吸收部位尚不能确定。在各肠段中,以CH-CEC 双层包覆胰岛素脂质体的吸收最佳。结论壳聚糖及其衍生物包覆脂质体能促进胰岛素经肠道吸收,并可提高其在肠道中的稳定性。

运用单向灌流模型研究莪术油中三成分对大鼠在体肠的吸收

目的 研究莪术油中三成分对大鼠在体肠的吸收情况。方法 运用单向灌流模型并采用HPLC法(配备二极管阵列检测器)同时测定莪术油中三成分在灌流液中的浓度。结果 灌流液中莪术油浓度为0.4,0.8和1.2mg·mL-1时,莪术醇、莪术二酮和吉玛酮表观吸收系数均较低,且均无显著性差异(P>0.05),各肠段的表观吸收系数也无显著性差异(P>0.05);吉玛酮和莪术二酮二者在体肠吸收情况无显著性差异(P>0.05),但均高于莪术醇,且存在显著性差异(P<0.01)。结论 灌流液中莪术油在0.4—1.2 mg·mL-1时,三成分的吸收无自身浓度抑制作用,在肠黏膜的转运均为被动扩散过程,且三成分无特殊的吸收窗。

黄芩苷和黄芩素大鼠在体胃、肠的吸收动力学研究

目的:研究黄芩苷和黄芩素在大鼠胃、肠的吸收动力学特征。方法:采用大鼠在体胃、肠吸收模型,以高效液相色谱法测定胃、肠灌注液中药物的含量。结果:黄芩苷在胃、小肠及结肠中的每小时吸收率分别为8.05%,-0.94%,2.32%;黄芩素在胃、小肠及结肠中的每小时吸收率分别为34.53%,30.61%,4.89%。黄芩素在十二指肠、空肠、回肠及结肠的每小时吸收速率常数分别为0.090 7,0.083 7,0.076 6,0.048 3。结论:黄芩苷只在胃中有一定程度的吸收,在小肠和结肠基本不吸收;黄芩素在胃和小肠中吸收良好,在结肠有少量吸收。黄芩素在各部位的吸收程度明显优于黄芩苷,提示黄芩素比黄芩苷更适于制成口服吸收制剂;黄芩素具有广泛的吸收窗,提示适宜制成缓控释制剂。

桂枝茯苓胶囊中有效成分的大鼠在体肠吸收研究

目的:研究桂枝茯苓胶囊中苦杏仁苷、芍药苷、丹皮酚等主要的3种成分在大鼠的肠吸收性质,了解中药组方对吸收的作用.方法:运用单向灌流模型并采用HPLC法分别测定桂枝茯苓胶囊内容物的灌流液以及直接溶解有这3种成分的灌流液在肠灌流过程中的浓度变化.结果:苦杏仁苷、芍药苷、丹皮酚分别在19.2～304.8、 18.4～329.5、 7.8～125 μg/mL浓度范围内,吸收量与浓度呈线性关系,无高浓度饱和现象,Ka、Kapp值基本保持不变;除丹皮酚外,在pH 5.0至pH 7.4范围内苦杏仁苷、芍药苷的吸收不受pH影响;3成分在各肠段的Ka、Kapp均无明显差异;仅含有上述3成分中一种成分的各个提取物的苦杏仁苷、芍药苷的Ka、Kapp值显著小于由配方药材提取得到的胶囊内容物的相应成分的Ka、Kapp值.结论:桂枝茯苓胶囊中3种有效成分在大鼠小肠主要以被动扩散方式吸收,且3成分无特殊的吸收窗;桂枝茯苓胶囊组方配伍显著增加苦杏仁苷、芍药苷的吸收.

卡马西平大鼠在体肠吸收动力学

目的研究卡马西平在大鼠各肠段的吸收动力学特征。方法采用大鼠在体肠灌流方法,研究卡马西平大鼠肠吸收动力学。结果卡马西平在整个肠道均吸收良好,吸收速度按十二指肠、结肠、回肠、空肠的顺序依次下降,吸收速度常数依次为0.230、0.182、0.178、0.165 h-1。药物在肠道的吸收呈现一级吸收动力学,吸收机制为被动吸收。结论卡马西平的吸收窗比较长,适合于制备日服一次的缓释给药系统。

淫羊藿黄酮类化合物的大鼠在体肠吸收研究

目的研究淫羊藿中黄酮类化合物在大鼠各肠段的吸收动力学特征。方法采用大鼠在体肠灌流模型对淫羊藿苷和淫羊藿总黄酮在大鼠各肠段的吸收特性进行研究。结果淫羊藿苷在大鼠各肠段的渗透系数按空肠、十二指肠、回肠、结肠顺序依次分别为(5.25±0.17),(4.27±0.28),(1.99±0.09),(0.80±0.03);淫羊藿总黄酮中淫羊藿苷在大鼠各肠段的渗透系数按空肠、十二指肠、回肠、结肠顺序依次分别为(3.65±0.18),(4.68±0.17),(1.64±0.08),(0.58±0.26)。结论淫羊藿总黄酮中有多种成分在大鼠肠段会发生代谢转化,其中淫羊藿苷经过大鼠肠段后代谢最为明显。

长春西汀的大鼠在体肠吸收研究

采用单向灌流技术考察长春西汀的大鼠在体肠吸收性质。结果表明,灌流速度对药物吸收速率常数(Ka)和表观吸收系数(Papp)有极显著影响(P<0.01);药物浓度对Ka和Papp无显著影响(P>0.05);药物在全肠道吸收较好,吸收窗主要在小肠,且小肠内无明显的特定吸收部位;羟丙基-β-环糊精在1%～4%范围内对药物的肠吸收无显著影响。

尼莫地平大鼠在体肠吸收动力学

目的研究尼莫地平在大鼠各肠段的吸收动力学特征。方法采用大鼠在体肠段灌流实验 ,主要从吸收部位、药物浓度、pH值等 3方面对尼莫地平的肠段吸收特性进行研究。结果尼莫地平在大鼠肠道内无特定吸收部位 ,各肠段吸收速率常数按十二指肠、空肠、结肠、回肠顺序依次下降 ,吸收速率常数分别为 0 0 6 87、0 0 6 2 0、0 0 5 97、0 0 4 89h-1。在 4 8～ 14 3μmol·L-1浓度内药物吸收量与浓度呈线性关系 ;在 pH 5 0～ 7 4内药物吸收不受 pH值影响。 结论尼莫地平在大鼠全肠段均有吸收 ,吸收符合一级动力学特征 ,吸收机制为被动扩散 ,适于制备日服

原位循环灌流法分离大鼠肝星状细胞

目的：为深入探讨肝纤维化的细胞机制，探索经济、稳定的肝星状细胞分离和培养方法。方法：采用胶原酶原位循环灌流法分离大鼠肝星状细胞，１８％Ｎｙｃｏｄｅｎｚ密度梯度离心纯化星状细胞。结果：星状细胞的得率为１×１０７～３×１０７／肝，纯度为９０％，存活率为９６％。结论：原位循环灌流法是有效的大鼠肝星状细胞的分离和培养方法。

酚红法和改良重量法分别研究葛根素的大鼠在体肠吸收机制

目的通过在体单向肠灌流法研究葛根素的肠吸收机制,比较酚红法与改良重量法在研究葛根素吸收机制上的适用性。方法采用酚红法、改良重量法校正灌流液体积,并用HPLC法对灌流前后葛根素的含量进行测定,研究不同质量浓度(100、200和400μg.mL-1)的葛根素在大鼠不同肠段的吸收情况。结果酚红法测得的葛根素的吸收参数基本为负值,其结果不符合常理。改良重量法测得葛根素在各肠段均有吸收,但各肠段之间差异无统计学意义,不存在明显吸收窗;葛根素浓度升高,肠吸收有所增加,且不存在饱和现象。结论改良重量法相对酚红法更适用于葛根素的在体肠吸收研究。

大鼠肠道对左旋延胡索乙素及其消旋体的吸收差异研究

考察延胡索乙素(THP)的吸收机制,并研究其消旋体与左旋延胡索乙素(l-THP)在大鼠肠道的吸收差异。应用单向灌流模型,采用HPLC法测定THP及l-THP在灌流液中的浓度变化。灌流液中THP质量浓度为8,16,32μg.mL-1时,THP吸收速率常数和有效吸收系数均无统计差异(P>0.05),各肠段的吸收速率常数和有效吸收系数也无统计差异(P>0.05);l-THP和THP在大鼠肠道吸收存在显著性差异(P<0.05);在肠道灌流液中加入P-糖蛋白(P-gp)抑制剂维拉帕米后,THP吸收显著增加,而l-THP吸收几乎不变。THP在肠黏膜的转运为被动扩散过程,无特殊吸收窗口;THP消旋体与l-THP的吸收差异可能与P-gp与右旋THP的选择性结合有关。

淫羊藿苷大鼠在体肠吸收动力学的研究

目的:研究淫羊藿苷在大鼠各肠段的吸收动力学特征。方法:采用大鼠在体肠灌流模型对淫羊藿苷在大鼠各肠段的吸收特性进行研究。结果:淫羊藿苷在大鼠各肠段的渗透系数按空肠、十二指肠、回肠、结肠顺序依次分别为(5.25±0.17)、(4.27±0.28)、(1.99±0.09)、(0.80±0.03),各肠段均能检测到淫羊藿次苷。结论:淫羊藿苷在大鼠肠段代谢成淫羊藿次苷后被吸收。

柚皮素大鼠在体肠吸收动力学的研究

目的研究柚皮素在大鼠小肠内的吸收特性。方法运用大鼠在体肠灌流模型,采用紫外分光光度法测定灌流液中柚皮素和酚红的浓度,计算柚皮素的吸收率和吸收速率常数。结果不同浓度的柚皮素在小肠的吸收率为(34.24±2.31)%,(38.35±2.20)%,(43.61±0.16)%,吸收速率常数为(0.195±0.002)h-1,(0.203±0.006)h-1,(0.211±0.009)h-1;柚皮素在不同肠段的吸收率为(15.96±0.25)%,(12.67±0.78)%,(7.42±1.43)%,(5.46±0.51)%,吸收速率常数为(0.101±0.008)h-1,(0.085±0.011)h-1,(0.063±0.009)h-1,(0.035±0.013)h-1;柚皮素在未结扎胆管和结扎胆管大鼠的小肠吸收率为(38.35±2.20)%和(30.77±4.80)%,吸收速率常数为(0.203±0.005)h-1和(0.164±0.004)h-1。结论质量浓度对于柚皮素的吸收无影响;柚皮素在不同肠段的吸收有显著性差异,十二指肠为最佳吸收部位。胆汁的分泌有利于柚皮素的吸收;初步推测柚皮素在小肠的吸收主要为被动转运方式,吸收动力学为一级吸收。

盐酸青藤碱大鼠肠吸收实验研究

目的研究盐酸青藤碱在大鼠不同肠段的吸收特性,为其剂型设计提供理论依据。方法以酚红为标示物,采用在体单灌流法进行肠吸收实验研究,高效液相色谱法测定灌流液中盐酸青藤碱和酚红的浓度,计算吸收性能参数。结果盐酸青藤碱在十二指肠、空肠、回肠、结肠的有效渗透系数(Peff)分别为0.65±0.15,0.54±0.26,0.45±0.14,0.28±0.12(×10-4cm.s-1),表明该药在大鼠各肠段均有较好的吸收。结论盐酸青藤碱适于制成日服1次的缓控释制剂。