大鼠在体肠灌流模型对豆腐果苷在体吸收的初步研究

目的应用大鼠在体肠灌流模型对豆腐果苷吸收机制进行研究。方法该实验在建立豆腐果苷在Krebs-Ringer缓冲液中的检测方法,及应用752紫外分光光度计测定Krebs-Ringer缓冲液中酚红溶液浓度的基础上,应用大鼠肠灌流模型研究豆腐果苷的吸收情况。结果通过该模型对豆腐果苷在大鼠十二指肠上部至回肠下部肠段中2 h内吸收情况的研究发现,豆腐果苷吸收迅速,15～20 min吸收即可达到平台。结论该实验建立了大鼠小肠灌流模型,并且将该模型用于豆腐果苷吸收情况的初步研究,为揭示豆腐果苷体内处置情况奠定了基础。     

柴胡疏肝散水提取物的肠吸收特性研究

目的 建立同时测定芍药苷、阿魏酸、芸香柚皮苷、柚皮苷、新橙皮苷、甘草酸含量的超高效液相色谱（UPLC）法,研究柴胡疏肝散水提物的肠吸收特性。方法 采用大鼠在体单向肠灌流和外翻肠囊实验模型,应用UPLC法测定柴胡疏肝散水提物中指标性成分（芍药苷、阿魏酸、芸香柚皮苷、柚皮苷、新橙皮苷和甘草酸）在不同时间点、不同部位肠道吸收量,计算吸收动力学参数,考察其肠吸收特征。结果 在体单向肠灌流模型结果表明,芍药苷、芸香柚皮苷、新橙皮苷、柚皮苷和甘草酸均为中等程度吸收的化学成分,而阿魏酸为完全吸收;外翻肠囊模型结果表明,芍药苷在空肠部位,阿魏酸、柚皮苷和新橙皮苷在十二指肠部位,芸香柚皮苷在十二指肠和空肠部位的吸收最佳,而甘草酸在各肠段的吸收无显著性差异。结论 肠道对柴胡疏肝散中6种指标性成分均有吸收,阿魏酸较其他5种指标性成分更易透过肠壁进入血液循环;不同肠段对6种指标性成分的吸收具有选择性。     

在体肠灌流模型研究灵仙新苷的大鼠肠吸收特性

目的:研究灵仙新苷在大鼠肠段的吸收特征。方法:以酚红为标示物,采用在体单向肠灌流模型,LC-MS/MS测定灵仙新苷在体肠灌流的浓度变化,研究灵仙新苷的吸收部位和吸收动力学特征。结果:灵仙新苷在大鼠小肠各肠段的吸收速率常数(Ka)、有效渗透系数(Peff)是十二指肠>空肠≈回肠,且十二指肠的Ka和Peff值与其他肠段存在显著性差异(P<0.05);灌流液中同一肠段不同浓度灵仙新苷的Ka和Peff均无统计学显著差异;盐酸维拉帕米和环孢素A均显著性降低对灵仙新苷的吸收(P<0.05)。结论:灵仙新苷在小肠有不同程度的吸收,其中在十二指肠吸收最好,药物浓度对灵仙新苷的Peff和Ka值无影响,其吸收机制为被动扩散,灵仙新苷可能不是P-糖蛋白底物。     

玳玳果黄酮降脂滴丸的肠吸收动力学特性

目的：考察玳玳果黄酮降脂滴丸的肠吸收特性并探讨其作用机制。方法：采用大鼠外翻肠囊模型,建立同时测定大鼠肠吸收液中玳玳果黄酮降脂滴丸特征药效成分新橙皮苷和柚皮苷含量的液-质联用（UPLC-MS）分析法,比较玳玳果黄酮降脂滴丸与原料玳玳果黄酮降脂提取物在大鼠不同肠段的累积吸收量,分析不同质量浓度大鼠空肠段的吸收过程,探讨其肠吸收部位及机制。结果：玳玳果黄酮降脂滴丸特征药效成分新橙皮苷和柚皮苷90 min时的累积吸收量由多到少依次是空肠、十二指肠、回肠和结肠;玳玳果黄酮降脂滴丸在高、中、低剂量下空肠的累积吸收量随时间的增加而增加,相关系数r>0.95,且随着药液质量浓度的增加新橙皮苷和柚皮苷的Ka均增加,符合一级药动学过程;在等剂量给药下,玳玳果黄酮降脂滴丸中新橙皮苷和柚皮苷的累积吸收量约是玳玳果黄酮降脂提取物的1.6倍。结论：玳玳果黄酮降脂滴丸在全肠道均有吸收,小肠的上中段为最佳吸收部位,新橙皮苷和柚皮苷吸收可能为被动吸收循环入体,制成的玳玳果黄酮降脂滴丸可显著改善提取物在肠道的吸收,提高其口服生物利用度。     

基于Ussing Chamber技术评价阿苯达唑纳米晶体在大鼠不同肠段的吸收特性

目的:研究阿苯达唑纳米晶体(ABZ-NCs)在大鼠不同肠段的吸收动力学特征.方法:采用尤斯室技术进行肠吸收试验,利用高效液相色谱法测定ABZ-NCs在大鼠十二指肠、空肠、回肠、结肠4个肠段的吸收状况,并考察不同浓度药物对肠吸收的影响,同时与ABZ片剂(T-ABZ)进行比较.结果:ABZ-NCs不同浓度在不同肠段均有吸收...     

建立大鼠原位肠-肝灌流模型评价绿原酸的代谢

目的：建立大鼠原位肠-肝灌流模型，运用该模型研究绿原酸在大鼠肠、肝中的代谢转化。方法：采用液相色谱质谱联用（HPLC-MS）法测定大鼠原位肠-肝灌流模型灌流液中绿原酸及其代谢产物咖啡酸、阿魏酸和马尿酸。结果：绿原酸十二指肠给药后，灌流液中主要活性代谢产物为阿魏酸，同时在灌流液中也检测到少量活性代谢产物咖啡酸和大量代谢终产物马尿酸。结论：大鼠原位肠-肝灌流模型适用于绿原酸生物转化和代谢动力学的研究；绿原酸在肠中存在广泛的代谢。     

芒果苷大鼠肠吸收特性研究

目的研究芒果苷在大鼠肠道的吸收动力学特征。方法采用大鼠在体肠循环实验,用超高效液相色谱法和紫外分光光度法分别测定芒果苷和酚红的浓度,考察药物浓度、pH值和不同肠段对芒果苷吸收的影响,并与知母水煎液比较芒果苷在大鼠肠道吸收的差异。结果芒果苷浓度为2.0,5.0,10.0,20.0μg.mL-1时,吸收速率常数(ka)分别是0.0541,0.0467,0.0491,0.0220 h-1,吸收百分率(Fa)分别是14.05%,13.14%,12.43%和5.82%;随肠液pH升高,ka和Fa依次增加;芒果苷在肠段内吸收存在差异,各肠段的吸收速率常数按结肠、十二指肠、回肠和空肠依次下降;知母水煎液组中,肠循环液中芒果苷含量的上升和新芒果苷含量的下降呈同步变化。结论芒果苷在大鼠小肠段的吸收存在高浓度饱和现象,并且受到药物浓度、肠循环液pH值、肠段等因素的影响。     

单向肠灌流法研究芍药苷和刺芒柄花苷的肠吸收特性

目的:采用在体单向肠灌流法研究芍药苷和刺芒柄花苷在大鼠不同肠段的吸收特性,探索复方给药对单一活性成分吸收的影响。方法:采用高效液相色谱法进行含量测定和方法学验证。色谱柱:Shim Pack ODS C₁₈(250 mm×4.6 mm,5μm);流动相:测定芍药苷时为甲醇-乙腈-1.0 mL·L^-1磷酸水溶液(15∶15∶70),测定刺芒柄花苷时为乙腈-1.0 mL·L^-1甲酸水溶液(55∶45);流速:1.0 mL·min^-1;检测波长:230 nm(芍药苷)、254 nm(刺芒柄花苷);柱温:30℃。通过对相同药物浓度在不同肠段、不同药物浓度对同一肠段有效渗透系数(Peff)的影响研究芍药苷和刺芒柄花苷的主要吸收途径,在灌流液中添加维拉帕米研究糖蛋白抑制剂对药物在十二指肠Peff的影响,通过比较单一成分与复方灌流后的Peff差异,研究复方形式对单一活性成分在肠道吸收的影响。结果:芍药苷和刺芒柄花苷的质量浓度均在0.5~60μg·mL^-1范围内,与相应的峰面积呈良好的线性关系,相关系数分别为0.9999和0.9998;日内精密度RSD分别小于2.5%和2.9%,日间精密度RSD均小于3.1%,稳定性RSD分别小于3.6%和3.3%。芍药苷和刺芒柄花苷在大鼠小肠的Peff由大到小顺序均为十二指肠、空肠、回肠。糖蛋白抑制剂维拉帕米对二者在十二指肠的吸收无显著影响,同时不同浓度的含药灌流液的Peff又具有显著的差别,具有浓度饱和现象,复方灌流液补阳还五汤中芍药苷和刺芒柄花苷的Peff高于单一成分灌流。结论:十二指肠为芍药苷和刺芒柄花苷最佳吸收肠段,以复方形式给药能够提高部分有效成分在肠道的吸收。     

芒果苷大鼠在体肠道吸收机制研究

目的:研究芒果苷大鼠在体肠道吸收机制。方法:采用大鼠在体肠段灌流模型,建立高效液相色谱/紫外分光光度法测定肠循环液中芒果苷的浓度,研究不同芒果苷浓度、胆汁及吸收部位对芒果苷吸收参数的影响。结果:芒果苷在5.0~25.0μg.mL-1浓度范围内对小肠吸收速率常数(Ka)无影响;在12.5μg.mL-1浓度下对结扎胆管大鼠的小肠Ka有影响;各肠段的Ka回肠>空肠>结肠>十二指肠,分别为0.164、0.132、0.125、0.107h-1。结论:芒果苷的吸收符合一级动力学特征,吸收机制为被动扩散;芒果苷在各肠段均有较好的吸收,胆汁使芒果苷在小肠的透过系数增大。     

白芷提取物对黄芩活性成分黄芩苷的吸收促进作用

研究白芷提取物对黄芩苷肠吸收的影响,初步探讨白芷促进黄芩苷吸收的机制。采用大鼠外翻肠囊模型研究黄芩苷在十二指肠、空肠、回肠及结肠的吸收特点,以及白芷对黄芩苷不同肠段吸收的影响,确定最佳促吸收部位;采用在体单向肠灌流模型研究黄芩苷不同浓度在最佳促吸收部位的吸收特性和白芷对黄芩苷的促吸收作用;建立大鼠肠灌流后肝门静脉取血模型,分析血中药物浓度,进一步验证白芷对黄芩苷的促吸收作用。结果发现黄芩苷吸收顺序为:回肠>结肠>空肠>十二指肠。加入白芷后十二指肠的吸收显著增加,因此选择十二指肠为研究肠段。黄芩苷在十二指肠的表观通透系数(Papp)和吸收速率常数(Ka)随着浓度的增加而逐渐增加,当浓度达到一定时,吸收具有自身浓度抑制作用,说明黄芩苷吸收机制可能是载体中介转运。加入盐酸维拉帕米后,黄芩苷的Papp和Ka值基本保持不变,说明黄芩苷可能不是P-糖蛋白(P-gp)底物。加入白芷后,两种吸收模型均表明黄芩苷在十二指肠的单位面积吸收量显著增加(P<0.01),肝门静脉血中药物分析也显示白芷可增加黄芩苷的吸收。     

托美丁在大鼠肠道的吸收动力学

目的:研究托美丁在大鼠各肠段的吸收动力学特征。方法:采用大鼠离体肠外翻模型,用HPLC法对托美丁进行检测,计算托美丁在肠道的吸收参数。结果:托美丁在全肠段均有良好吸收,吸收速率按空肠、十二指肠、结肠、回肠的顺序依次下降,吸收速率常数依次为0.292 8,0.214 5,0.186 9,0.080 9 h-1。结论:托美丁在大鼠整个肠段的吸收呈现一级动力学特征,吸收机制为被动扩散。     

广枣提取物大鼠肠外翻的吸收研究

目的研究广枣提取物中2种主要代表性成分没食子酸和原儿茶酸在大鼠不同肠段、不同时间的吸收规律。方法构建大鼠肠外翻模型,应用HPLC法测定广枣提取物肠吸收液中没食子酸和原儿茶酸含量,计算其吸收参数,并分析其在大鼠小肠不同部位、不同时间的吸收特征。结果 2.5h为肠外翻最终检测时间点,在建立的分析色谱条件下,没食子酸和原儿茶酸色谱峰处台氏液和广枣提取物中其他成分对其无干扰,专属性良好。广枣提取物中原儿茶酸和没食子酸在各肠段均为线性吸收,r2值均达到0.90以上,不同肠道部位的累计吸收结果为:十二指肠>空肠>回肠>结肠。结论广枣提取物中原儿茶酸和没食子酸在肠道的吸收特征符合零级吸收速率,其最佳吸收部位为十二指肠。     

Intestinal absorption of digoxin and interaction with nimodipine in rats

It is known that digoxin, which is a liposoluble cardiac glycoside, is well absorbed from intestine. In the present study, the absorption rates of digoxin from rat duodenum and the proximal and terminal parts of small intestine were determined in vitro. The isolated everted duodenum and intestinal sacs were put into oxygenated Tyrode solution at 37 degrees C. The Tyrode solution on the outer, mucosal side of intestinal segments contained 0.3 microM digoxin. Samples from the internal serosal side of the intestinal sacs were taken at 30, 60 and 120 min after the start of the experiments. The concentration of digoxin in the samples of fluid were determined using a radioimmunoassay method. The effect of nimodipine (0.1 and 0.2 mM) on digoxin absorption was also evaluated on the terminal segment of rat intestine. The interaction of nimodipine (0.5 mg/kg) and digoxin (0.2 mg/kg) was investigated in vivo when they were given perorally to rats. The duodenal absorption of digoxin was lower than in the small intestine. The highest absorption occurred in the terminal segment of the small intestine. Nimodipine increased the absorption of digoxin from the terminal segment of intestine in vitro, while it did not affect the serum digoxin concentration in vivo.     

Use of everted sacs of mouse small intestine as enzyme sources for the study of drug oxidation activities in vitro

1. The use of everted sacs of the small intestine as an enzyme source for the study of the first-pass metabolism of xenobiotics by cytochrome P450s (P450, CYP) is described. Several drug oxidation activities for testosterone, chlorzoxazone, tolbutamide, bufuralol and warfarin were observed when everted sacs (1-cm segment) from different parts of mouse small intestine were incubated with an NADPH-generating system and each substrate. 2. Most of the drug hydroxylase activities resided in the upper part of mouse small intestine and these activities were much higher than those of intestinal microsomes. Drug oxidation activities decreased along the distance from the upper part of the small intestine except for warfarin hydroxylation. 3. Testosterone 6beta-hydroxylation in the everted sacs exhibited the highest catalytic activities among the drug oxidations tested here. In the upper part of the small intestine, the testosterone 6beta-hydroxylase activities of everted sacs subjected once to freezing and thawing were substantially decreased compared with the untreated everted sacs. 4. Testosterone 6beta-hydroxylase activities in the everted sacs of the small intestine were significantly inhibited by ketoconazole. Immunoreactive proteins using anti-CYP3A antibodies were detected in the upper and middle parts of the small intestine. 5. The results demonstrated that the upper part of the mouse small intestine serves as the major site for intestinal P450 mediated first-pass metabolism. Everted sacs of the small intestine are therefore useful for the study of drug metabolism as well as of transport and absorption.     

Use of everted sacs of mouse small intestine as enzyme sources for the study of drug oxidation activities in vitro

1. The use of everted sacs of the small intestine as an enzyme source for the study of the first-pass metabolism of xenobiotics by cytochrome P450s (P450, CYP) is described. Several drug oxidation activities for testosterone, chlorzoxazone, tolbutamide, bufuralol and warfarin were observed when everted sacs (1-cm segment) from different parts of mouse small intestine were incubated with an NADPH-generating system and each substrate. 2. Most of the drug hydroxylase activities resided in the upper part of mouse small intestine and these activities were much higher than those of intestinal microsomes. Drug oxidation activities decreased along the distance from the upper part of the small intestine except for warfarin hydroxylation. 3. Testosterone 6β-hydroxylation in the everted sacs exhibited the highest catalytic activities among the drug oxidations tested here. In the upper part of the small intestine, the testosterone 6β-hydroxylase activities of everted sacs subjected once to freezing and thawing were substantially decreased compared with the untreated everted sacs. 4. Testosterone 6β-hydroxylase activities in the everted sacs of the small intestine were significantly inhibited by ketoconazole. Immunoreactive proteins using anti-CYP3A antibodies were detected in the upper and middle parts of the small intestine. 5. The results demonstrated that the upper part of the mouse small intestine serves as the major site for intestinal P450 mediated first-pass metabolism. Everted sacs of the small intestine are therefore useful for the study of drug metabolism as well as of transport and absorption.     

外翻肠囊法研究茶芎苯酞类有效部位中4种成分的肠吸收特性

目的：研究茶芎苯酞类有效部位（CPTA）中4种成分在大鼠离体肠中的最佳吸收部位、吸收机制和吸收动力学过程,为CPTA剂型与处方设计提供生物药剂学依据。方法：采用大鼠离体外翻肠囊模型,利用HPLC法建立CPTA中4种成分在小肠液中的含量测定方法。取麻醉后大鼠的十二指肠、空肠、回肠和结肠段作为受试肠段建立外翻肠囊模型,计算各肠段中各成分的累积吸收量、吸收速率常数K_a和表观渗透系数P_app值。结果：建立了HPLC法测定CPTA中4种成分在SD大鼠肠道中的方法。4种成分随着浓度的增大,120 min累积吸收呈现不断增加趋势,低、中、高3种药物浓度相比具有显著性差异（P<0.05）;中、高两种吸收液浓度时,药物累积吸收量十二指肠>结肠>回肠>空肠。同一肠段的4种成分比较,洋川芎内酯A吸收最强,Z-藁本内酯次之,新蛇床内酯和正丁基苯酞的吸收最少;4种肠段中,十二指肠的P_app值最大,回肠与空肠的最小,洋川芎内酯A与Z-藁本内酯的P_app具有显著性差异（P<0.05）。结论：茶芎苯酞类有效部位中4种成分在不同肠段皆有较好吸收,药物吸收方式可能为被动转运,可以制备成速释制剂、缓控释制剂等。离体肠翻转模型成本较低,操作简单,结果可靠,可以用于初步研究药物在不同肠段的吸收特性。     

溴吡斯的明在大鼠离体肠的吸收动力学

目的观察溴吡斯的明在各肠段的吸收动力学特征。方法采用大鼠外翻肠囊模型,反相离子对色谱法测定不同浓度(25、50、100 mg.L-1)的溴吡斯的明在各肠段的吸收量,计算吸收速率常数(Ka)和表观渗透系数(Papp),并考察P-糖蛋白抑制剂(环孢素和维拉帕米)对药物吸收的影响。结果在25、50、100 mg.L-1溴吡斯的明条件下,Ka按十二指肠、空肠、回肠、结肠依次减小,不同浓度溴吡斯的明对同一肠段的Ka无显著影响(P>0.05),十二指肠、空肠、回肠间的Ka无显著差异(P>0.05),在50、100 mg.L-1溴吡斯的明条件下,结肠的Ka与十二指肠、空肠、回肠比较有显著差异(P<0.05,P<0.01)。随着溴吡斯的明浓度增加,各肠段Papp显著降低,不同肠段间的Papp有显著差异(P<0.05,P<0.01)。P-糖蛋白抑制剂对溴吡斯的明吸收无影响(P>0.05)。结论溴吡斯的明在十二指肠有较好吸收,在空肠和回肠有一定吸收,在结肠中吸收较少。     

Absorption and metabolism of acetaminophen by the in situ perfused rat small intestine preparation

The in situ perfused rat small intestine preparation was used to examine the extents of segmental absorption and metabolism of acetaminophen (A). Additionally, the preparation was employed to investigate any intestinal excretion of A and its conjugates from the circulation to the intestinal lumen. In this preparation, blood perfusate (300 ml) recirculated the intestinal preparation at 7.5 ml/min, entering via the superior mesenteric artery and returned to the reservoir via the portal vein. To demonstrate the extent of segmental absorption, metabolism, and excretion by different segments of the intestine, tracer doses of 3H-A (0.41 to 0.55 mumol in 0.3 ml of saline) were administered into the (a) entire intestine; (b) segments (first, second, and third) of one-third the length of the intestine, by instillation of the dose into the lumens of the segments; and (c) reservoir of perfusate. Exudates of luminal fluid from the injected segment and segments not exposed to drug were monitored for A and its conjugates during the experiment and at the end of 2 hr. Absorption of A was usually complete by 60 min; the extent of absorption of A at the end of 2 hr by the entire length of the intestine and by its three (first, second, and third) individual segments were 71.7 +/- 2.6, 50.5 +/- 4.0, 73.9 +/- 2.1, and 58.8 +/- 6.1% of dose (mean +/- SE), respectively. At the end of 2 hr, the total amount of acetaminophen glucuronide in perfusate and luminal fluid accounted for 3.1-5.5% and 0.14-0.1% of dose, respectively, among these preparations; acetaminophen sulfate was present only as a small percentage of dose in the lumen. Glucuronidation activity, when expressed as a percentage of the absorbed dose, was fairly constant for the entire intestine and first and second segments (8%) but decreased slightly for the third segment (7%). When A was present in blood perfusing the intestine, no metabolite was detected in perfusate or luminal fluid. Instead, unchanged A was excreted (5.6% dose) into the lumen. The effect of dose and vehicle on the extents of absorption and metabolism of A in the preparation was investigated by the instillation of different doses of A (0.16, 99.2, and 396.9 mumol in 0.3 ml of polyethene glycol 400) into the entire intestine at the duodenum.(ABSTRACT TRUNCATED AT 400 WORDS)     

千金藤素对非索非那定肠吸收的影响

目的研究千金藤素对非索非那定大鼠肠吸收的影响。方法采用大鼠肠外翻模型,以维拉帕米为阳性对照,研究千金藤素对非索非那定肠吸收的影响,并用反相高效液相色谱法测定大鼠肠黏膜内外两测的非索非那定浓度。结果非索非那定在大鼠十二指肠有吸收,千金藤素能增加非索非那定的吸收。结论千金藤素能增加非索非那定吸收,机制可能是抑制了P-糖蛋白的外排。