微渗析技术在药代动力学和药物代谢研究中的应用

1　前言微渗析 (ｍｉｃｒｏｄｉａｌｙｓｉｓ)是一种在体取样技术 (ｉｎｖｉｖｏｓａｍｐｌｉｎｇｔｅｃｈｎｉｑｕｅ) ,是在线渗析技术的一个分支。最早由美国和瑞典的研究人员首先提出了这一概念[1] 。他们的构思是在动物组织内植入一个“人工毛细血管” ,用生理溶液 (灌注液 ,ｐｅｒｆｕｓａｔｅ)对其进行灌注 ,组织细胞间液中的分子则可以通过管壁进入渗析液 (ｄｉａｌｙｓａｔｅ) ,然后通过对渗析液中的物质进行分析来反映组织液中物质组成。这一技术自 80年代初逐步发展成熟起来 ,首先成为实验精神药理学和神经生理学的一个有力的实验…     

微透析在药代动力学研究中的应用

微透析是一较新的组织间隙液采样技术，近几年来在体微透析技术在药代动力学和药效学的研究中被广泛应用，本文描述了微透析采样的原理及其在药代动力学中的应用特点，并对其在人体药代动力学研究中的应用进行了介绍。     

微透析取样技术及其在药代动力学中的应用

本文综述了近年来国外有关微透析取样技术在药代动力学中的应用，介绍了微透析取样技术的原理、组成以及微透析探针的类型，重点介绍了在体微透析取样技术在动物和人药代动力学中的应用。表明微透析取样技术在药代动力学中的应用具有广阔的前景。     

微透析技术在生命科学研究中的应用

简要介绍微透析这种较新的生物采样技术及其基本原理,参考最新文献综述其在生物医学方面的多种应用,指出微透析技术将来在药代动力学、药效学以及疾病诊断控制方面极具价值.     

微透析取样技术在药物代谢研究中的应用及前景

微透析取样技术已发展了 2 0年[1-4 ] ,最初主要用于研究脑内神经递质的释放。微透析取样装置由微透析探针及微量注射泵组成 ,微透析探针由一长4 - 10ｍｍ的再生纤维透析膜固定在一根微径导液管上组成 ,可除去分子量大于 50ｋｕ的分子 ,透析膜前有保护头 ,一般微透析探针的外径为 30 0 μｍ。微型泵将灌注液泵入探针 ,当灌注液与细胞外液组成完全一致时 ,通过透析膜无水及离子交换 ,只有小分子物质顺浓度梯度泵入或泵出探针所埋入的生理环境。进入膜内腔的溶液为灌注液 ,透出膜内腔的溶液为透析液。由于微透析探针的外径只有 30 0 μｍ ,取…     

微透析技术在肿瘤药物研究中的应用进展

微透析技术具有连续动态微创取样优势,能实时在线研究正常生理和肿瘤病理情况下肿瘤药物在体内,尤其是肿瘤组织局部的分布、代谢和消除,利用PK/PD参数模型设计个体化给药方案,预防和减少肿瘤药物的毒性反应。同时,微透析技术还可以应用于肿瘤细胞外间质微环境中生化物质的监测以及肿瘤药物局部给药治疗,是肿瘤药物研究的重要技术手段。本文对近年来微透析在肿瘤药物研究中的应用进展进行检索和归纳,为微透析技术在取样、监测以及治疗领域的进一步研究应用提供参考。     

微透析技术在抗菌药物药动学和药效学中的应用

微透析技术是一项新兴的体内药物分析技术。通过微透析技术与药动学和药效学模型结合,实现对组织或细胞外游离态药物浓度及其相应药理效应的同时研究,不仅有利于进一步明确药物的剂量-效应关系,制定临床最佳给药方案,而且也为个体化给药提供了科学依据。本文综合近年文献,对微透析技术的基本原理以及在抗菌药物药动学和药效学研究中的应用作一综述。     

毛细管电泳与微透析技术在药物动力学中的应用

毛细管电泳具有操作简便,分离速度快,分离效率高,重现性好,样品用量少,分析灵敏度高,可自动化管理等优点;微透析技术是利用微透析探针等技术对生物样品等进行透析,具有取样量小,可连续取样等特点.二者结合对于药物动力学研究十分适合.     

微透析技术在药动-药效学结合研究中的应用

微透析技术能直接、有效地对作用部位细胞外液中的内源性及外源性化合物进行持续检测,是药动-药效学结合研究的重要工具,具有不可替代的作用及广阔的应用前景。本文概述了微透析技术的基本原理及特点,并重点介绍了其在药动-药效学结合研究中的应用。     

Biopharmaceutics: Drug Metabolism and Pharmacokinetics: Circadian Variations in the Pharmacokinetics of Pentoxifylline in Man

Optimization of therapy by chronopharmacology requires knowledge of rhythmic manifestations of disease activity and chronopharmacokinetic data of the drugs prescribed. Rhythmic functioning of the cardiovascular system in healthy and diseased subjects is manifested as circadian rhythms in blood pressure, cardiac output, heart rate, etc. The disposition of several cardiovascular drugs in man has been reported to be time-dependent. This study reports the effect of time of administration on the disposition of pentoxifylline. Twelve healthy volunteers were treated with 400 mg pentoxifylline orally at 0100, 0700, 1300 and 1900 h in a randomized crossover Latin-square design with a wash-out period of one week. Serum samples were analysed for unchanged pentoxifylline by HPLC. Pharmacokinetic parameters were calculated using a model-independent method. The mean values of various pharmacokinetic parameters after drug treatment at these times were, respectively: maximum plasma concentration (C_max) 485 ± 174, 646 ± 175, 735 ± 271 and 781±217 ng mL^?1; time to reach the maximum plasma concentration (T_max) 1.90±0.39, 1.66±0.4, 1.31 ± 0.41 and 1.32 ± 0.44 h, mean residence time (MRT) 3.8 ± 0.8, 2.9 ± 0.5, 2.9 ± 0.4 and 2.7 ± 0.3 h, elimination half-life (t1/2) 1.93 ± 0.86, 1.23 ± 0.3, 1.39 ± 0.3 and 1.23 ± 0.18 h and volume of distribution at steady state (Vd_ss/f) 11991 ± 4862, 8823 ± 3484, 8275 ± 2357 and 7063 ± 1950 mL kg^?1. The mean C_max value was significantly (P < 0.05) lower after drug administration at 0100 h than after other time-points whereas mean T_max, MRT, Vd_ss/f and t1/2 values were significantly (P < 0.05) higher. These variations might be because of time-dependent changes in absorption and biliary excretion of pentoxifylline and should be borne in mind when designing sustained action dosage forms for the drug.     

微透析技术及其在经皮给药系统中的应用

综述了经皮微透析技术及其近年来在经皮给药系统中的应用,包括经皮吸收药物的药动学研究及生物利用度和生物等效性评价。     

The Use of Microdialysis in Pharmacokinetics and Pharmacodynamics

Microdialysis is a new in vivo sampling technology applied to the study of pharmacokinetics and drug metabolism in the blood and soft tissues of living systems. A small-diameter probe containing a dialysis membrane is implanted into tissue and perfused with a suitable fluid. Low-molecular-weight substances passively diffuse through the semipermeable membrane along a concentration gradient, resulting in the collection of purified dialysate samples. The advantage of this approach over blood sampling and dissection of tissues is the ability to sample blood and extracellular fluid with minimal tissue damage or alteration of fluid balance. Sampling several tissues simultaneously and continuously in animal models allows data to be obtained that more directly reflect interactions of drugs at their sites of activity and detoxification. Techniques such as this will have a tremendous impact on preclinical and clinical pharmacologic research.     

Potential Use of Microdialysis in Pharmacokinetics: A Protein Binding Study

Pharmaceutical Research -     

Drug Metabolism and Laboratory Anesthetic Protocols in the Rat: Examination of Antipyrine Pharmacokinetics

Pharmaceutical Research -     

Microdialysis Evaluation of the Ocular Pharmacokinetics of Propranolol in the Conscious Rabbit

Purpose. This study was conducted to assess the effects of anesthesia and aqueous humor protein concentrations on ocular disposition of propranolol. Methods. Rabbits were anesthetized and a microdialysis probe was inserted into the anterior chamber of one eye; the contralateral eye served as a control. At timed intervals after probe placement, a 100-l sample of aqueous humor was aspirated from each eye to determine protein concentration. In vitro protein binding parameters were used to simulate the impact of protein concentration on propranolol disposition. To assess the influence of anesthesia, probes were implanted in the anterior chamber of each eye. After >5-day stabilization, conscious and anesthetized rabbits (n = 3/group) received a 200-g topical dose of [³H] DL-propranolol in each eye; propranolol was assayed in probe effluent. Results. Changes in aqueous humor protein concentrations were observed following probe insertion. Simulations demonstrated that the unbound propranolol AUC (2.4-fold) in aqueous humor should be reduced due to protein influx. Intraocular propranolol exposure in anesthetized rabbits was 8-fold higher than in conscious rabbits, and 1.9-fold higher than in rabbits without a post-surgical recovery period. Conclusions. Anesthesia and time-dependent aqueous humor protein concentrations may alter ocular pharmacokinetics, and must be taken into account in the design of microdialysis experiments.     

Study on In Vitro Metabolism and In Vivo Pharmacokinetics of Beauvericin

Beauvericin (BEA) is a well-known mycotoxin produced by many fungi, including Beaveria bassiana. The purpose of this study was to evaluate the in vitro distribution and metabolism characteristics as well as the in vivo pharmacokinetic (PK) profile of BEA. The in vitro metabolism studies of BEA were performed using rat, dog, mouse, monkey and human liver microsomes, cryopreserved hepatocytes and plasma under conditions of linear kinetics to estimate the respective elimination rates. Additionally, LC-UV-MSⁿ (n = 1~2) was used to identify metabolites in human, rat, mouse, dog and monkey liver microsomes. Furthermore, cytochrome P450 (CYP) reaction phenotyping was carried out. Finally, the absolute bioavailability of BEA was evaluated by intravenous and oral administration in rats. BEA was metabolically stable in the liver microsomes and hepatocytes of humans and rats; however, it was a strong inhibitor of midazolam 1′-hydroxylase (CYP3A4) and mephenytoin 4′-hydroxylase (CYP2C19) activities in human liver microsomes. The protein binding fraction values of BEA were >90% and the half-life (T_1/2) values of BEA were approximately 5 h in the plasma of the five species. The absolute bioavailability was calculated to be 29.5%. Altogether, these data indicate that BEA has great potential for further development as a drug candidate. Metabolic studies of different species can provide important reference values for further safety evaluation.