盐酸氯米帕明大鼠在体肠吸收动力学研究

目的研究盐酸氯米帕明在大鼠肠道的吸收特性。方法采用大鼠在体肠灌流实验方法,利用高效液相色谱法同时测定肠回流液中药物及酚红的浓度,通过酚红的浓度校正相应时刻供试液的体积。结果盐酸氯米帕明浓度为5、10、25μg/ml时小肠的吸收速率常数(ka)为(0.74±0.04)、(0.78±0.03)、(0.77±0.05)h-1;在十二指肠、空肠、回肠和结肠的ka分别为(0.590±0.026)、(0.670±0.032)、(0.680±0.030)和(0.560±0.031)h-1。结论盐酸氯米帕明在大鼠肠道均有良好的吸收。盐酸氯米帕明在小肠的吸收呈表观一级动力学过程,吸收机制为被动扩散。     

阿苯达唑自微乳大鼠在体肠吸收研究

目的研究阿苯达唑自微乳在小肠各部位的吸收情况。方法采用大鼠在体肠单向灌流实验,RP-HPLC法测定药物浓度,根据药物进出小肠各段中的质量减少量来求算出药物的吸收速率。结果在十二指肠、空肠、回肠中的吸收速率常数依次是1.78×10-2,2.15×10-2和1.25×10-2·min-1。结论阿苯达唑自微乳在整个小肠段都有吸收,且小肠中段吸收较好。     

炎琥宁大鼠在体肠吸收实验研究

目的考察炎琥宁在大鼠小肠中的吸收状况,为炎琥宁口服肠溶制剂的制备提供理论依据。方法采用大鼠在体肠循环法,通过测定各时间点炎琥宁的剩余药量计算吸收速率。结果低、中、高(6μg.mL-1、1 mg.mL-1和1.4mg.mL-1)三种浓度炎琥宁溶液在小肠的吸收速率(Ka)分别为1.64×10-2、5.87×10-3和8.26×10-3;吸收率分别为89%、55%和69%。1 mg.mL-1炎琥宁溶液在小肠的不同部位(十二指肠、空肠、回肠)吸收速率分别为1.11×10-2、1.20×10-2和0,吸收率分别为86%、0.86%和0。结论炎琥宁在小肠有较好的吸收,低浓度吸收优于高浓度,因此,该药适合制备小肠定位释放的缓控释制剂。     

乙酰丙酮钒在大鼠胃肠道吸收的初步研究

目的:研究乙酰丙酮钒在大鼠胃、小肠和大肠的吸收特性.方法:采用大鼠在体灌流实验,用石墨炉原子吸收法测定大鼠血浆中钒(V)浓度.结果:乙酰丙酮钒在10mg·kg-1剂量下在胃和大肠的吸收速率常数分别为2.853h-1和0.587h-1,AUC分别为158.6ng·mL-1·h和642.7ng·mL-1·h;在不同给药剂量(以钒计)10,25和50mg·kg-1时小肠的吸收速率常数分别为1.414,1.664和17.118h-1,AUC分别为1 714.0,4 641.2和5 554.7 ng·mL-1·h.结论:大鼠胃和大肠是乙酰丙酮钒的不良吸收部位,而小肠有较好吸收,吸收方式可能是被动扩散.     

马来酸曲美布汀大鼠肠吸收动力学研究

目的研究马来酸曲美布汀在大鼠不同肠段的吸收动力学特征,为其剂型设计提供生物药剂学依据。方法采用大鼠在体肠循环法研究马来酸曲美布汀的吸收部位和吸收动力学特征,利用紫外-可见分光光度法和反相-高效液相色谱法分别测定肠循环液中酚红和甲硝唑浓度。结果马来酸曲美布汀在十二指肠、空肠、回肠及结肠中的吸收速度常数分别为0.230±0.023、0.084±0.051、0.202±0.021、0.170±0.038(h-1),不同药物浓度(10、20、25μg/ml)在小肠的吸收速率常数分别为0.393±0.044、0.354±0.017、0.365±0.075(h-1),胆总管引流与不引流时药物在小肠的吸收速率常数分别为0.354±0.017、0.370±0.014(h-1)。结论马来酸曲美布汀在全肠段中均有吸收,吸收在10～25μg/ml浓度范围内符合一级动力学特征,吸收机制为被动扩散,胆汁排泄对药物吸收影响不大。     

冰片对利福平大鼠小肠的吸收动力学影响

目的研究冰片对利福平大鼠小肠吸收动力学影响。方法将大鼠分为单用利福平和合用冰片利福平 2组 ,采用高效液相色谱法研究大鼠灌胃给药后药物在大鼠小肠动力学的情况 ,计算出合用组和单用利福平组的大鼠小肠吸收速度常数和每小时吸收速率。结果合用组和单用组的吸收速度常数分别为 (0 12 98± 0 0 2 6 4 )和 (0 0 934± 0 0 12 9)h-1,吸收速率分别为 (11 2 115±2 35 6 2 ) %和 (7 5 985± 1 4 4 11) % ,两组间的小肠吸收速度常数及吸收速率有显著性差异。结论冰片显著提高大鼠对利福平的生物利用度 ,可能是因为冰片能促进大鼠小肠的吸收     

翻转肠囊法研究吸收促进剂对小肠吸收苦参碱的作用

目的 :研究不同吸收促进剂对苦参碱小肠吸收的促进作用。方法 :采用离体小肠翻转肠囊实验 ,考察了卵磷脂、脱氧胆酸钠、吐温 80、波洛沙姆 188和十二烷基硫酸钠对苦参碱小肠吸收的促进效果 ,并根据对计算苦参碱的表观渗透系数Papp和增渗比ER来选择最佳的吸收促进剂及用量。结果 :苦参碱在空肠、十二指肠、回肠吸收速率没有显著性差异 (Ρ >0 0 5 )。在几种促进剂中 ,以 0 2 %SDS对苦参碱的吸收促进作用最为明显 ,Papp =3 36×10 5cm s,ER =1 99。结论 :加入促进剂 0 2 %SDS可以增加苦参碱的离体小肠吸收。     

阿替洛尔大鼠在体胃肠道吸收动力学研究

目的:研究阿替洛尔在大鼠胃、肠及各肠段的吸收动力学特征,为其剂型设计提供生物药剂学依据.方法:采用大鼠在体肠灌流实验,利用紫外-可见分光光度法和HPLC法分别测定酚红和阿替洛尔的含量.结果:药物在胃和小肠中2 h的吸收百分率分别为8.63%±1.04%、8.91%±2.73%;阿替洛尔在十二指肠、空肠、回肠、结肠的吸收速率常数各为(0.0706±0.0161)h-1、(0.0360±0.0111)h-1、(0.0465±0.0126)h-1、(0.0479±0.0083)h-1;药物质量浓度为20、50、100 μg·mL-1时,在肠的吸收速率常数分别为(0.0568±0.0308)h-1、(0.0360±0.0111)h-1、(0.0531±0.0095)h-1;当pH值为5.0、6.5、7.4时,肠的吸收速率常数分别为(0.0528±0.0051)h-1、(0.0603±0.0322)h-1、(0.0465±0.0126)h-1.结论:阿替洛尔在大鼠肠道各部分均有吸收,且吸收呈一级动力学过程,吸收机制为被动扩散;药物在大鼠肠内的吸收不受药物浓度和pH的影响;药物的吸收按十二指肠、结肠、回肠、空场的顺序依次下降.     

川芎嗪大鼠在体肠吸收动力学

目的:探讨川芎嗪在大鼠各肠段的吸收动力学特征.方法:采用大鼠在体小肠回流装置,以UV法和HPLC法分别测定酚红和川芎嗪的含量.结果:川芎嗪在小肠的吸收速率常数(Ka)于不同药物浓度2.5,5,10,25 mg·L-1时分别为0.360 8,0.388 1,0.444 6,0.385 9 h-1;不同pH值7.8,6.8,5.4时分别为0.466 4,0.413 9,0.270 5 h-1;在十二指肠,空肠,回肠和结肠时分别为0.291 3,0.220 9,0.172 8,0.133 3 h-1.结论:药物浓度对Ka无影响;在pH 7.8～5.4范围内,随药液pH值的增大,药物的Ka显著增加;药物在十二指肠、空肠和回肠的吸收较好,在结肠的吸收较差;川芎嗪在肠道的吸收呈一级动力学过程,吸收机制为被动扩散.     

原钒酸钠对小肠糖吸收的影响

目的　观察原钒酸钠对葡萄糖及麦芽糖吸收的影响 ,并初步探讨其影响糖吸收的机制。方法　①正常Wistar大鼠分为正常对照组、生理盐水对照组、阿卡波糖组 (30mg·kg-1)、原钒酸钠大剂量 (16mg·kg-1)、中剂量 (4mg·kg-1)和小剂量 (1mg·kg-1)组 ,分别灌胃葡萄糖和麦芽糖后 ,用氧化酶法测空腹血糖值及糖耐量。②从小肠上段提取α 葡萄糖苷酶 ,检测原钒酸钠对酶的抑制作用。结果　①原钒酸钠可延迟灌胃葡萄糖 (2 2g·kg-1)引起的血糖升高且 3个剂量组血糖曲线下面积 (AUC)均低于对照组 ,分别为 (8 2 4±0 6 3)mmol·h-1·L-1(P <0 0 1) ,(9 6 9± 0 38)mmol·h-1·L-1(P <0 0 1) ,(13 76± 0 39)mmol·h-1·L-1(P <0 0 5 ) ;②原钒酸钠和阳性对照组均可延缓灌胃麦芽糖 (2 2g·kg-1)引起的血糖升高 ,且大、中剂量可抑制血糖峰值升高 (P <0 0 5 ) ,各给药组AUC均低于对照组 ,大剂量和中剂量为(8 97± 1 5 6 )和 (6 19± 0 4 7)mmol·h-1·L-1均低于阳性对照组 (13 10± 0 4 3)mmol·h-1·L-1(P <0 0 5 ) ;③原钒酸钠 1、10、10 0 μmol·L-1均可抑制正常大鼠小肠α 葡萄糖苷酶的活性 ,其抑制百分率分别为 5 9 76 %、6 8 18%、87 2 2 % ,且大剂量和中剂量均大于阳性对照组的 6 0 94 % ,分别为P<0     

Saturable rate of cefatrizine absorption after oral administration to humans

This study examined the absorption kinetics of cefatrizine, an amino-beta-lactam antibiotic, after oral administration of a single 500-mg dose to 12 healthy volunteers. Plasma concentrations were determined by high performance liquid chromatography. The plots of the percentage of drug unabsorbed and the apparent rate of cefatrizine absorption as a function of time showed, first, a delay and, then, an almost constant rate of absorption with a tendency to move toward first-order kinetics at the end of the process. Three compartmental models incorporating a lag time and first-order elimination kinetics, but differing in their input rate, were used for analysis of the time course of cefatrizine plasma concentrations. The model with first-order absorption kinetics was clearly inadequate. The results were improved with the model for which the rate of absorption is constant, but a model incorporating saturable absorption kinetics of the Michaelis-Menten type improved the fit further. This last model was statistically superior to the constant-rate input model in 6 out of 12 subjects, according to the likelihood-ratio method. Because of the innovative feature of the model incorporating the Michaelis-Menten equation, simulations of the effect of altering the model parameters and the dose administered on the concentration-time profile, were performed. Different hypotheses which might explain why cefatrizine absorption kinetics fits the Michaelis-Menten equation were examined. The observation of saturable absorption kinetics is consistent with a carrier-mediated transport previously reported to occur in the gastrointestinal tract of rats.     

Saturable rate of cefatrizine absorption after oral administration to humans

This study examined the absorption kinetics of cefatrizine, an amino--lactam antibiotic, after oral administration of a single 500-mg dose to 12 healthy volunteers. Plasma concentrations were determined by high performance liquid chromatography. The plots of the percentage of drug unabsorbed and the apparent rate of cefatrizine absorption as a function of time showed, first, a delay and, then, an almost constant rate of absorption with a tendency to move toward first-order kinetics at the end of the process. Three compartmental models incorporating a lag time and first-order elimination kinetics, but differing in their input rate, were used for analysis of the time course of cefatrizine plasma concentrations. The model with first-order absorption kinetics was clearly inadequate. The results were improved with the model for which the rate of absorption is constant, but a model incorporating saturable absorption kinetics of the Michaelis-Menten type improved the fit further. This last model was statistically superior to the constant-rate input model in 6 out of 12 subjects, according to the likelihood-ratio method. Because of the innovative feature of the model incorporating the Michaelis-Menten equation, simulations of the effect of altering the model parameters and the dose administered on the concentration-time profile, were performed. Different hypotheses which might explain why cefatrizine absorption kinetics fits the Michaelis-Menten equation were examined. The observation of saturable absorption kinetics is consistent with a carrier-mediated transport previously reported to occur in the gastrointestinal tract of rats.     

阿克他利大鼠在体肠吸收动力学

目的研究阿克他利大鼠在体肠吸收动力学特征。方法采用大鼠在体单向灌流法进行肠吸收实验,以吸收速率常数(ka)和表观吸收系数(Papp)为指标,从灌流速度、药物浓度和吸收部位3个方面对阿克他利肠吸收动力学特征进行考察。结果不同灌流速度下的ka和Papp有极其显著性差异(P<0.01);药物浓度在一定范围内对ka和Papp无显著性影响(P>0.05);小肠各段(十二指肠、空肠、回肠)的ka和Papp无显著性差异(P>0.05);小肠与结肠的ka存在极其显著性差异(P<0.01),Papp存在显著性差异(P<0.05)。结论阿克他利在整个肠道吸收良好,但吸收窗主要在小肠,在结肠段的吸收相对较差。     

不同纯度葛根素提取物的大鼠小肠吸收动力学研究

目的研究不同纯度葛根素提取物的大鼠小肠吸收动力学参数的差异。方法利用大鼠在体肠吸收模型,以HPLC法测定不同纯度葛根素提取物中葛根素的小肠吸收情况,计算动力学参数。结果不同纯度葛根提取物中葛根素在大鼠小肠内的吸收为一级动力学过程。葛根素纯度越高,其吸收速率越低,半衰期越长,累积吸收率降低。结论葛根素纯度提高,并不利于其肠道吸收。     

盐酸去氢骆驼蓬碱大鼠肠吸收动力学的研究

目的　研究盐酸去氢骆驼蓬碱在大鼠胃肠道各段的吸收动力学特征 ,为其剂型设计提供生物药剂学依据。方法　采用大鼠在体肠循环法分别研究盐酸去氢骆驼蓬碱在大鼠十二指肠、空肠、回肠及结肠中的吸收动力学特征。采用反相高效液相色谱法测定循环液中的药物浓度。结果　盐酸去氢骆驼蓬碱在十二指肠、空肠、回肠及结肠中的吸收速度常数Ka分别为 :( 0 .30 92± 0 .0 5 9) ,( 0 .2 0 6 4± 0 .0 4 4 ) ,( 0 .2 85 8± 0 .0 81) ,( 0 .2 0 0 9± 0 .0 80 )h-1。结论　盐酸去氢骆驼蓬碱在十二指肠、空肠、回肠及结肠中均能较好地吸收     

Investigation of Absorption Kinetics by the Phase Plane Method

Purpose. To develop a simple approach for investigating absorption kinetics, which does not require modeling assumptions or intravenous data. Methods. The concentration (C) -time (t) data are plotted as a phase plane plot (dC/dt versus C). Errorless C,tdata were generated from one and two compartment models employing first-order, zero-order and Michaelis-Menten input kinetics, and the phase plane plots were constructed. A simple test based on the ratio of slopes of the separate linear regression analyses of absorption and elimination data of the phase plane plot is proposed to justify or not the presence of zero-order input kinetics. Errant data were used to assess the performance of the test developed. Literature data of theophylline and nitroglycerin formulations were analyzed using the phase plane plot. Input rate-time profiles were constructed for one compartment model drugs utilizing the data of the phase plane plot. Results. The geometric forms of the phase plane plots derived from the errorless data of the various pharmacokinetic models were found to be indicative of the absorption kinetics. Very good results were obtained when the test for the discernment of absorption kinetics was applied to errant data. Zero-order absorption kinetics were justified (i) for the transdermal absorption of nitroglycerin and (ii) only for a certain period of time, for the gastrointestinal absorption of theophylline. Conclusions. Investigation of absorption kinetics can be accomplished with the phase plane method. The cumulative character of the classical percent absorbed versus time plots can be misleading in justifying the presence of zero-order input kinetics.     

氧化苦参碱大鼠肠道吸收机理及吸收部位的研究

目的探明氧化苦参碱在大鼠肠道各区段的吸收动力学特征、吸收部位及吸收机制,以期对药物长效缓释制剂的设计提供重要依据。方法采用大鼠在体肠灌流吸收实验,研究了氧化苦参碱的吸收部位和吸收动力学特征。结果氧化苦参碱在肠道的吸收呈现一级吸收动力学特征且吸收机制为被动转运。药物在小肠部位吸收良好,吸收速度按空肠、回肠、十二指肠、结肠的顺序依次下降,吸收速率常数依次为0.237、0.225、0.200和0.062h-1。结论氧化苦参碱的吸收窗比较长,适于制备缓释给药系统。     

绞股蓝总皂苷的大鼠在体肠吸收动力学研究

目的研究绞股蓝总皂苷在大鼠各肠段的吸收动力学特征,为制剂设计提供理论依据。方法采用大鼠在体肠吸收模型和紫外分光光度法研究药物在大鼠各肠段的吸收特性。结果绞股蓝总皂苷在0.17~0.37mg/mL范围内对小肠吸收速率常数Ka无显著性影响;十二指肠、空肠、回肠、结肠各肠段的吸收速率常数Ka无显著性差异。结论绞股蓝总皂苷在大鼠肠道的吸收呈一级动力学过程,为被动扩散,吸收窗较广,可开发成缓释制剂。     

Evaluation of a chronically isolated internal loop in the rat for the study of drug absorption kinetics

A model is described to study absorption kinetics of drugs in the unanesthetized rat. The surgical technique consists of a long-term isolation of an intestinal segment inside the animal. This isolated loop is used in perfusion experiments. In this model the effects of anesthesia and surgical trauma on absorption kinetics are absent. In addition, this model allows for cross-over experimental schemes. Absorption kinetics are evaluated on the basis of steady-state blood levels (Css) of the perfused drug, since the animal can be used in experiments over a long time period. Steady-state blood levels can be used as a measure of the absorption if the compound under investigation shows linear elimination kinetics. Dantrolene sodium was used as a model compound to evaluate this technique. The elimination of dantrolene sodium followed linear kinetics after different intravenous doses in the same rat. The half-life of elimination (t1/2 beta) of dantrolene sodium was approximately 45 min. Perfusions of two different concentrations of dantrolene sodium in the same rat showed that an increase of the perfusate concentration results in a proportional increase in the Css. A prerequisite for performing cross-over experiments is that the absorption characteristics of the isolated segment are constant during the experimental period. This model showed a constant absorption of dantrolene sodium on consecutive days, over a two-week period, in the same rat.     

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 1次缓释给药系统