独活有效成分大鼠在体单向灌流肠吸收

为了考察独活提取物中二氢欧山芹醇乙酸酯、蛇床子素、二氢欧山芹醇当归酸酯等3种主要有效成分在大鼠的肠吸收性质,了解中药提纯后对大鼠肠吸收的影响，本文运用单向灌流模型并采用HPLC法测定独活提取物I(总香豆素含量＜10%)灌流液中3种成分在体肠灌流的浓度变化，并与独活提取物II(总香豆素含量≥60%)进行比较。结果表明二氢欧山芹醇乙酸酯、蛇床子素及二氢欧山芹醇当归酸酯的质量浓度分别为62～555 μg·mL^-1、101～887 μg·mL^-1和19～186 μg·mL^-1，吸收量与浓度呈线性关系,无高浓度饱和现象，吸收速率常数(K_a)、吸收渗透系数(P_app)值基本保持不变。3种成分在大鼠小肠主要以被动扩散方式吸收；在各肠段均有吸收，其中结肠吸收最好，各肠段的K_a、 P_app是结肠＞十二指肠＞空肠＞回肠，且结肠的K_a、 P_app值显著大于其他肠段；独活提取物II中3种成分的K_a、 P_app值显著小于独活提取物I中相应成分。     

水飞蓟宾磷脂复合物的制备与大鼠生物利用度的研究

目的制备水飞蓟宾磷脂复合物并对其理化性质进行考察，比较水飞蓟宾磷脂复合物与水飞蓟宾原料在大鼠体内的生物利用度。方法以丙酮为溶剂，加入水飞蓟宾和大豆磷脂，充分搅拌至澄清，真空干燥即得黄白色固体；用DSC，UV，IR等方法测定水飞蓟宾磷脂复合物的理化性质；两组大鼠分别灌胃给予水飞蓟宾磷脂复合物和水飞蓟宾原料后，用RP-HPLC法测定不同时间血浆中总的和游离的水飞蓟宾的浓度，通过3P97程序计算药代动力学参数。结果研究表明水飞蓟宾磷脂复合物是以非共价键结合，而不是新的化合物；水飞蓟宾磷脂复合物明显改善了水飞蓟宾在水中及正辛醇中的溶解性能；大鼠灌胃给予水飞蓟宾磷脂复合物，体内吸收符合一级吸收一室模型，血浆中游离药物和总的药物浓度的T_max分别为10 min和2 h；C_max分别为0.11和1.08 μg·mL^-1；T_1/2分别为2.18和3.84 h；AUC_0～∞分别为1.71和12.94 μg·mL^-1·h，而给予水飞蓟宾原料，大鼠体内吸收的浓度在检测限以下，不能测定。结论水飞蓟宾磷脂复合物与水飞蓟宾原料相比亲脂性显著增加，从而增强了水飞蓟宾在胃肠道中的吸收，提高了水飞蓟宾的口服生物利用度。     

柚皮素、橙皮素的大鼠在体肠吸收特性研究

目的 考察柚皮素、橙皮素在大鼠肠道的吸收特性,并考察P-糖蛋白(P-gp)对这2种成分吸收的影响。方法 采用大鼠在体肠灌流模型,以超高效液相色谱(UPLC)测定灌流液中柚皮素、橙皮素的含量,计算有效渗透系数(P_eff*)及10 cm肠段吸收百分比。结果 20 μmol·L^-1柚皮素在十二指肠、空肠、回肠、结肠4个肠段的P_eff*值分别为2.77±0.43,2.39±0.30,1.90±0.53,3.15±0.30;20 μmol·L^-1橙皮素分别为2.51±0.18,2.29±0.12,1.99±0.14,3.38±0.20。当两者加了P-gp抑制剂维拉帕米后,柚皮素、橙皮素在4个肠段的吸收均显著增加(P<0.05)。结论 柚皮素、橙皮素在大鼠肠道内吸收较好,但两者均可被肠黏膜上的P-gp外排。     

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1.2 mg·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。     

基于溶解氧乙酰螺旋霉素极谱平行催化氢波的研究

目的提出一种极谱测定乙酰螺旋霉素(ASPM)的新方法。方法应用单扫描极谱法,在含溶解氧的0.1 mol·L^-1 NH₄Cl-NH₃·H₂O(pH 8.9)缓冲液中ASPM产生1个灵敏的平行催化氢波［峰电位E_p=-1.63 V(vs SCE)］。结果该平行催化氢波的二阶导数峰峰电流i″与ASPM浓度在1.74×10^-3～3.48 μg·mL^-1呈良好线性关系(r=0.997 9,n=13),检出限为5.80×10^-4 μg·mL^-1(3σ)。对0.871 μg·mL^-1 ASPM溶液进行13次平行测定,RSD为1.24%。结论本方法可用于ASPM片剂中ASPM含量的测定。     

川芎油自微乳化软胶囊大鼠在体肠吸收研究

为了考察川芎油剂型选择的合理性,进行了原料、包合物和自微乳化软胶囊的比较吸收实验;并进一步明确自乳化软胶囊的小肠吸收特点,进行了不同浓度、不同肠段、有无胆汁分泌的在体肠吸收实验。通过药液在肠腔内循环,以藁本内酯为川芎油的指标性成分测定不同时间回流液中蒿本内酯浓度变化,得到药物的吸收情况。结果表明,自微乳化软胶囊显著提高藁本内酯的吸收 (P < 0.001), 效果最好。400 μg·mL^-1藁本内酯的吸收显著高于200和100 μg·mL^-1 (P < 0.001),而后两个浓度的吸收无差异。胆管结扎与否不影响药物吸收。自乳化软胶囊可被大鼠全肠段吸收,其中十二指肠吸收最好,各肠段K_a、P_app是十二指肠>空肠>回肠=结肠。

     

普罗布考包合物胶囊在家犬体内的药代动力学与相对生物利用度

目的研究普罗布考包合物胶囊在家犬体内的药代动力学与相对生物利用度。方法用高效液相色谱法测定6条健康犬po 250 mg普罗布考片(制剂A)或普罗布考包合物胶囊(制剂B)后不同时间血浆中活性药物的浓度,绘制药-时曲线,计算药代动力学参数及相对生物利用度。结果制剂A和制剂B的药-时曲线符合二室模型,其T_max均为(9.3±2.1) h,C_max分别为(1.5±1.0) μg·mL^-1和(2.3±0.9) μg·mL^-1,AUC_0～240分别为(85±56) μg·h·mL^-1和(134±55) μg·h·mL^-1。以制剂A为参比,制剂B中普罗布考的相对生物利用度为(198±90)%,两种制剂的AUC_0～240有显著性差异(P<0.05)。结论初步分析认为,改善普罗布考的水溶性是提高普罗布考生物利用度的关键因素之一。     

HPLC法测定化妆品原料2-羟乙基脲及杂质尿素的含量

目的 建立化妆品原料2-羟乙基脲的高效液相色谱（high performance liquid chromatography,HPLC）含量测定方法,并检测其杂质尿素的含量,以实现对2-羟乙基脲的质量控制。方法采用Capcell PAK ADME C_{18色谱柱（4.6 mm×250 mm,5 μm）;以水为流动相;柱温30℃;流速为1.0 mL·min^-1;进样量10 μL;检测波长194 nm。结果 2-羟乙基脲和尿素分别在1.168～116.8 μg·mL^-1（r=0.999 7）和1.032～206.5 μg·mL^-1（r=0.9992）范围内浓度与峰面积有良好的线性关系,平均回收率分别为98.0%和97.1%,检出限分别为0.12 μg·mL^-1和0.21 μg·mL^-1,定量限分别为0.36 μg·mL^-1和0.52 μg·mL^-1。结论 本方法准确度高,重复性好,检测灵敏度符合检测要求,可用于化妆品原料2-羟乙基脲及其杂质尿素的含量测定方法。}     

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8，16，32 μg·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。     

蒲地蓝消炎口服液对头孢克洛在大鼠肠道吸收的影响

目的 建立小肠灌流液中头孢克洛的高效液相色谱(HPLC)分析方法, 考察蒲地蓝消炎口服液对头孢克洛在大鼠小肠吸收的影响, 为临床联合用药的合理性提供实验依据。方法 采用大鼠在体单向肠灌流实验模型, 应用重量法校正灌流液体积, HPLC测定灌流液中头孢克洛, 计算头孢克洛肠吸收参数。结果 头孢克洛在各肠段均有良好吸收, 小肠不同部位头孢克洛的吸收速率常数(K_a)与有效渗透系数(P_eff)大小为十二指肠> 空肠≈回肠, 各肠段间的吸收无统计学差异;联合应用蒲地蓝消炎口服液时, 头孢克洛在全场段的吸收均有所减少, 十二指肠处显著减少(P<0.05), 其他肠段处无统计学差异(P> 0.05)。结论 研究结果表明蒲地蓝消炎口服液会影响头孢克洛的小肠吸收, 因此两药联合使用时产生较好的药效不是通过促进头孢克洛的吸收而实现的, 而是二者共同作用的结果。     

Intestinal permeability of forskolin by in situ single pass perfusion in rats

The intestinal permeability of forskolin was investigated using a single pass intestinal perfusion (SPIP) technique in rats. SPIP was performed in different intestinal segments (duodenum, jejunum, ileum, and colon) with three concentrations of forskolin (11.90, 29.75, and 59.90 μg/mL). The investigations of adsorption and stability were performed to ensure that the disappearance of forskolin from the perfusate was due to intestinal absorption. The results of the SPIP study indicated that forskolin could be absorbed in all segments of the intestine. The effective permeability (P (eff)) of forskolin was in the range of drugs with high intestinal permeability. The P (eff) was highest in the duodenum as compared to other intestinal segments. The decreases of P (eff) in the duodenum and ileum at the highest forskolin concentration suggested a saturable transport process. The addition of verapamil, a P-glycoprotein inhibitor, significantly enhanced the permeability of forskolin across the rat jejunum. The absorbed fraction of dissolved forskolin after oral administration in humans was estimated to be 100 % calculated from rat P (eff). In conclusion, dissolved forskolin can be absorbed readily in the intestine. The low aqueous solubility of forskolin might be a crucial factor for its poor oral bioavailability.     

Biopharmaceutics classification and intestinal absorption study of apigenin

The aim of the study was to characterize the biopharmaceutics classification system (BCS) category of apigenin (AP) using intrinsic dissolution rate (IDR) and rat intestinal permeability, and to investigate the intestinal absorption mechanism of AP in rats. In the present investigation, equilibrium solubility and intrinsic dissolution rate (IDR) of AP were estimated in phosphate buffers. Effective intestinal permeability (P(eff)) of AP was determined using single-pass intestinal perfusion (SPIP) technique in four segments (duodenum, jejunum, ileum and colon) of rat intestine at three concentrations (10, 50 and 100μg/ml). The aqueous solubility of AP in tested phosphate buffers was very poor with maximum solubility of 2.16μg/ml at pH 7.5. The IDR of AP was very low with a value of 0.006mg/min/cm(2). The minimum and maximum P(eff)s determined by SPIP were 0.198×10(-4) and 0.713×10(-4)cm/s at jejunum and duodenum site, respectively. In addition, the concentration-dependent permeability behavior was observed in the duodenum and jejunum, which suggested that AP was transported by both passive and active carrier-mediated saturable mechanism in these two intestinal segments. However, the observed concentration-independent permeability behavior in ileum and colon indicated primarily passive transport mechanism of absorption of AP in the last two intestinal segments. AP was classified as class II drug of the BCS due to its low solubility and high intestinal permeability. AP could be well absorbed in the whole intestine with the main absorption site at duodenum. The absorption of AP in four intestinal segments exhibited different transport mechanisms.     

Intestinal permeability of chlorpyrifos using the single-pass intestinal perfusion method in the rat

The intestinal transport of chlorpyrifos (CPF), an organothiophosphate pesticide, was investigated using the single-pass intestinal perfusion (SPIP) technique in male, Sprague-Dawley rats. SPIP was performed in each isolated region of the small intestine (i.e. duodenum, jejunum and ileum) with three concentrations of CPF (0.1, 2.0 and 10 microM) at a flow rate of 0.25 ml/min. Preliminary binding and stability studies were conducted to ensure that the loss of CPF in the SPIP study can be attributed to intestinal absorption. The effective permeability (P(eff)) of CPF was determined for each segment and concentration. CPF exhibits a high intestinal permeability over the length of the small intestine indicative of compounds that are well absorbed. Decreases in permeability values at the highest CPF concentration studied in the duodenum and ileum suggest a saturable transport process. Based on these results, passive, transcellular diffusion dominates the intestinal transport mechanism of CPF, with a saturable transport process evident in the duodenum and ileum. The P(eff) of CPF is in the range of drugs with high intestinal permeability and high fraction of dose absorbed indicating that CPF readily crosses the intestine. The dependence of CPF's P(eff) on concentration in the duodenum and ileum suggests that CPF is transported by a combination of mechanisms across the intestine. Using established relationships, the human fraction dose absorbed for CPF was estimated to be >99%. The permeability values obtained from this study may be useful in models of exposure assessment.     

The effect of amiloride on the in vivo effective permeability of amoxicillin in human jejunum: experience from a regional perfusion technique.

The purpose of this human intestinal perfusion study (in vivo) was twofold. Firstly, we aimed to determine the effective in vivo jejunal permeability (P(eff)) of amoxicillin and to classify it according to the Biopharmaceutics Classification System (BCS). Secondly, we investigated the acute effect of amiloride on the jejunal P(eff) of amoxicillin. Amoxicillin, a beta-lactam antibiotic, has been reported to be absorbed across the intestinal mucosa by both passive diffusion and active transport. A regional single-pass perfusion of the jejunum was performed using a Loc-I-Gut perfusion tube in 14 healthy volunteers. Each perfusion lasted for 200 min and was divided into two periods of 100 min each. The concentration of amoxicillin entering the jejunal segment was 300 mg/l in both periods, and amiloride, an inhibitor of the Na+/H+ exchanger, was added at 25 mg/l in period 2. The concentrations of amoxicillin and amiloride in the outlet jejunal perfusate were measured with two different HPLC-methods. Antipyrine and [14C]PEG 4000 were added as internal standards to the perfusion solution. Amiloride had no significant effect on the jejunal P(eff) of amoxicillin. The human in vivo jejunal P(eff) for amoxicillin was 0.34+/-0.11 x 10(-4) and 0.46+/-0.12 x 10(-4) cm/s in periods 1 and 2, respectively. The high jejunal P(eff) for amiloride was 1.63+/-0.51 x 10(-4) cm/s which predicts an intestinal absorption of more than 90%. Following the BCS amoxicillin was classified as a low P(eff) drug, and amiloride had no acute effect on the in vivo jejunal P(eff) of amoxicillin.     

盐酸麻黄碱的大鼠肠吸收研究

目的：研究盐酸麻黄碱的肠吸收机制。方法：利用大鼠在体单向肠灌流模型,采用HPLC法测定灌流液中盐酸麻黄碱含量,分别考察灌流速度、盐酸麻黄碱质量浓度、不同肠段以及P-糖蛋白抑制剂对盐酸麻黄碱肠吸收的影响。结果：灌流速度对盐酸麻黄碱吸收速率常数（Ka）和表观吸收系数（Papp）有极显著影响（P〈0.01）;灌流液中盐酸麻黄碱质量浓度对Ka和Papp无显著影响（P〉0.05）;盐酸麻黄碱在小肠各肠段（十二指肠、空肠和回肠）的Ka和Papp无显著性差异（P〉0.05）,但其Ka值显著大于在结肠处的值（P〈0.05）,而各肠段的Papp无显著性差异（P〉0.05）,P-糖蛋白抑制剂对盐酸麻黄碱在各肠段的Ka和Papp无显著影响（P〉0.05）。结论：盐酸麻黄碱在大鼠肠道内的吸收机制为被动扩散,不存在饱和吸收;其在全肠道吸收较好,吸收窗主要在小肠,且小肠内无明显的特定吸收部位;盐酸麻黄碱可能不是P-糖蛋白的底物。     

甘草主成分及其提取物肠吸收差异的多元化分析

考察甘草苷、甘草酸及甘草提取物中相应成分的大鼠在体肠吸收差异。运用大鼠在体肠灌流模型,采用UPLC和HPLC法同时测定肠灌流液、胆汁和颈静脉血样中甘草苷和甘草酸浓度,并结合肠道酶共孵育实验及对两种成分表观油水分配系数的测定,多元化比较分析甘草中甘草苷、甘草酸及提取物中相应成分在大鼠体内的吸收代谢特性。结果发现,甘草苷、甘草酸及甘草提取物中相应成分在大鼠肠道的有效渗透系数Peff值均小于0.3,表明两种成分肠道吸收均较差。各成分在十二指肠、空肠、回肠和结肠中吸收均无显著性差异;各成分单体与甘草提取物中相应成分比较发现,甘草提取物中甘草酸的各肠段Peff值略有增加,但无显著性差异;甘草提取物中甘草苷在回肠段的Peff值有显著性提高(P<0.05),其余肠段均无显著性差异,提示甘草提取物中其他成分促进甘草苷的吸收,但对甘草酸无明显影响。同时收集的提取物及单体的胆汁、血浆及肠道酶共孵育样品中均未检测到甘草苷、甘草酸及代谢产物,表明提取物中其他成分对于两种成分的影响在短时间(1～3 h)内可能未能提高其吸收入血及胆汁中的含量。     

五味子有效成分的大鼠在体单向灌流肠吸收

考察五味子提取物中五味子醇甲、五味子甲素、五味子乙素3种主要有效成分在大鼠的肠吸收性质。本文以酚红为标示物,运用在体单向肠灌流模型并采用HPLC法测定五味子提取物中3种主要有效成分在大鼠十二指肠、空肠、回肠及结肠灌流的浓度变化。结果发现,五味子提取物中3种有效成分的每种成分在不同浓度的吸收速率常数(Ka)和有效渗透系数(Peff)均有显著性差异(P<0.05)。随着浓度的增加,其Ka、Peff值均先升高而后下降,存在高浓度饱和现象,提示其在机体内的转运可能存在主动转运或促进扩散;3种有效成分在各肠段均有较好吸收,其中十二指肠吸收最好,空肠与回肠的吸收相近无显著差异(P>0.05);3种有效成分之间在不同肠段的吸收均存在显著性差异(P<0.05),十二指肠中五味子甲素吸收最好,其他肠段的Ka、Peff大小顺序依次是五味子甲素>五味子乙素>五味子醇甲,且两两之间都存在显著性差异(P<0.05)。