基于纳米技术的结肠靶向给药系统研究进展

通过纳米技术将药物直接纳米化或包封于纳米载体后进行结肠靶向给药,可使药物在胃、十二指肠、空肠、回肠前端不释放药物,直至将药物运送至回盲部才释放,从而发挥结肠局部或全身治疗作用.这一纳米给药技术能消除体内生理环境的作用,防止药物进入结肠靶点前被破坏或降解.利用纳米药物载体比表面积大、界面活性高的特点,通过对其进行表面修饰,还可避免其被体内的免疫系统识别、吞噬,克服体内的"生物屏障",从而实现体内结肠靶向给药[1].     

结肠吸收及结肠靶向给药

目的：对目前结肠吸收及其靶向给药方面的研究进行综述。方法：讨论药物结肠吸收特点和结肠靶向给药方法。结果：结肠是多肽药物口服的最佳吸收部位和缓控释制度口服持续吸收的重要部位。结肠靶向制剂可用于结肠局部病患的治疗和多肽药物的口服给药。结论：结肠吸收及其靶向给药是有意义而又有许多有待研究的领域。     

口服结肠靶向给药系统的研究进展

口服结肠靶向给药系统在药物转运和治疗结肠局部疾病方面具有重要作用。本文总结了口服结肠靶向给药系统近年来的研究概况,并对结肠靶向药物制剂的体内、外评价方法作一介绍。     

肠道疾病治疗中的口服结肠靶向给药系统

口服结肠靶向给药在治疗肠道疾病方面具有使用方便、结肠部位药物浓度较高的优点；其应用类型有3种：利用结肠特殊生理特性、靶向免疫调节细胞和生物黏附原理的结肠靶向给药系统。现对此3种口服结肠靶向给药系统的制备和应用进行综述。     

结肠靶向给药系统的研究

２０年前 ,人们对用于溃疡性结肠炎的药物吡柳磺胺 (Ｓｕｌｆ＿ａｓａｌａｚｉｎｅ)的作用方式已经有了充分的了解 ,并且发现口服轻泻剂只有到达大肠后才发挥作用。因此 ,人们对结肠靶向给药产生了兴趣 ,并且不断地开发各种结肠靶向给药系统［１］。升结肠和大部分横结肠只有口服途径能接触到 ,直肠给药很少能把药物运送到结肠 ,所以发展口服结肠靶向给药系统具有重要意义。口服结肠靶向给药系统中的药物在上消化道中不释放 ,只有当药物到达人体回盲部后 ,才能使给药系统把药物释放出来 ,并且在结肠部发挥局部或全身治疗作用。１结肠靶向给…     

壳聚糖在药物制剂中的应用研究进展

综述壳聚糖在生物大分子口服给药、pH敏感释药、靶向给药、纳米药物载体等药物制剂方面的应用研究进展。     

基于炎症环境的口服结肠靶向给药系统研究进展

口服结肠靶向给药系统由于能改善结肠局部疾病的治疗效果和降低副作用而成为该领域的研究热点。口服给药系统设计方法的不断发展显著提高了药物在结肠部位的生物利用度,然而,要使药物在发病期能够发挥治疗效果,还须关注到结肠炎症时胃肠道出现生理条件变化的影响。纳米技术已经作为提高药物在结肠炎症病灶区摄取的新策略而应用于口服剂型设计中,本文主要介绍该纳米给药系统的设计方法和研究进展。     

口服结肠给药系统的研究进展

口服结肠靶向给药系统(oral colon targetting drug deliv-ery system,OCTDDS))将治疗结肠疾病的药物靶向输送至结肠,不仅降低常规的口服或直肠给药的毒副作用,且能将药物输送至病灶处,减少给药剂量,提高患者的顺应性;还能提高多肽、蛋白等类药物口服给药的生物利用度。笔者将近年有关口服结肠给药系统的研究综述如下。1口服结肠释药系统的应用1.1时控给药根据时辰药理学原理,应用药剂手段使药物在一定的时滞后释放,使之与人的生理周期相匹配,可用于治疗哮喘、高血压、心绞痛、消化道溃疡及风湿性关节炎等具有节律性的疾病。结肠靶向给药…     

口服结肠定位给药系统的研究进展

口服结肠定位给药系统（oral colon—specific drug delivery system，OCDDS）是通过多种制剂技术使药物口服后，在胃及小肠内不释放，只有到达回盲部或结肠部位才定位释放药物的一种新型药物控释系统。利用结肠定位给药系统可将治疗结肠疾病的药物靶向输送至结肠，不仅降低了常规的口服或直肠给药的毒副作用，且能将药物输送至病灶处，可减少给药剂量，提高疗效，从而提高患者的顺应性；同时结肠靶向给药可以避免药物在胃肠道上端被胃肠道酶所降解，提高了多肽、蛋白、疫苗类药物的口服给药的生物利用度。     

抗肿瘤药物靶向载体系统的研究与开发

综述肿瘤靶向给药的基础和抗肿瘤药物靶向载体系统的发展。分类介绍普通被动靶向载药系统（如微乳、传统脂质体、聚合物纳米粒、固体脂质纳米粒、纳米脂质载体、药-脂结合物纳米粒等）、表面修饰的被动靶向载药系统及主动靶向载药系统（如免疫脂质体、免疫聚合物纳米粒及受体-配体介导靶向纳米载体）的研究与开发。在传统药物制剂的基础上，发展抗肿瘤药物的新型靶向载体系统，改善药物在体内的代谢动力学特性，增加药物定向富集到肿瘤部位甚至肿瘤细胞内，提高疗效，降低毒副作用，是近年来备受关注的课题。     

Polysaccharide-based micro/nanocarriers for oral colon-targeted drug delivery

Oral colon-targeted drug delivery has attracted many researchers because of its distinct advantages of increasing the bioavailability of the drug at the target site and reducing the side effects. Polysaccharides that are precisely activated by the physiological environment of the colon hold greater promise for colon targeting. Considerable research efforts have been directed towards developing polysaccharide-based micro/nanocarriers. Types of polysaccharides for colon targeting and in vitro/in vivo assessments of polysaccharide-based carriers for oral colon-targeted drug delivery are summarised. Polysaccharide-based microspheres have gained increased importance not just for the delivery of the drugs for the treatment of local diseases associated with the colon (colon cancer, inflammatory bowel disease (IBD), amoebiasis and irritable bowel syndrome (IBS)), but also for it’s potential for the delivery of anti-rheumatoid arthritis and anti-chronic stable angina drugs. Besides, Polysaccharide-based micro/nanocarriers such as microbeads, microcapsules, microparticles, nanoparticles, nanogels and nanospheres are also introduced in this review.     

Poly(butylcyanoacrylate) and Poly(ε-caprolactone) Nanoparticles Loaded with 5-Fluorouracil Increase the Cytotoxic Effect of the Drug in Experimental Colon Cancer

The clinical use of 5-fluorouracil, one of the drugs of choice in colon cancer therapy, is limited by a nonuniform oral absorption, a short plasma half-life, and by the development of drug resistances by malignant cells. We hypothesized that the formulation of biodegradable nanocarriers for the efficient delivery of this antitumor drug may improve its therapeutic effect against advanced or recurrent colon cancer. Hence, we have engineered two 5-fluorouracil-loaded nanoparticulate systems based on the biodegradable polymers poly(butylcyanoacrylate) and poly(ε-caprolactone). Drug incorporation to the nanosystems was accomplished by entrapment (encapsulation/dispersion) within the polymeric network during nanoparticle synthesis, i.e., by anionic polymerization of the monomer and interfacial polymer disposition, respectively. Main factors determining 5-fluorouracil incorporation within the polymeric nanomatrices were investigated. These nanocarriers were characterized by high drug entrapment efficiencies and sustained drug-release profiles. In vitro studies using human and murine colon cancer cell lines demonstrated that both types of nanocarriers significantly increased the antiproliferative effect of the encapsulated drug. In addition, both nanoformulations produced in vivo an intense tumor growth inhibition and increased the mice survival rate, being the greater tumor volume reduction obtained when using the poly(ε-caprolactone)-based formulation. These results suggest that these nanocarriers may improve the antitumor activity of 5-fluorouracil and could be used against advanced or recurrent colon cancer.KEY WORDS: 5-fluorouracil, colon cancer, poly(butylcyanoacrylate), poly(ε-caprolactone), polymeric nanoparticles     

口服结肠靶向释药系统的制备及应用

目的由于在治疗肠道或某些全身性疾病中具有特殊的优点,口服结肠靶向给药系统受到更多的关注。但消化道的复杂性导致影响药物在结肠靶向释药的因素较多,重现性不好。本文对经口服药物结肠靶向释药的生理因素、目前已有的制备技术及应用进行综述。     

Targeted pharmaceutical nanocarriers for cancer therapy and imaging

The use of various pharmaceutical nanocarriers has become one of the most important areas of nanomedicine. Ideally, such carriers should be specifically delivered (targeted) to the pathological area to provide the maximum therapeutic efficacy. Among the many potential targets for such nanocarriers, tumors have been most often investigated. This review attempts to summarize currently available information regarding targeted pharmaceutical nanocarriers for cancer therapy and imaging. Certain issues related to some popular pharmaceutical nanocarriers, such as liposomes and polymeric micelles, are addressed, as are different ways to target tumors via specific ligands and via the stimuli sensitivity of the carriers. The importance of intracellular targeting of drug- and DNA-loaded pharmaceutical nanocarriers is specifically discussed, including intracellular delivery with cell-penetrating peptides.     

Polymers for colon targeted drug delivery

The colon targeted drug delivery has a number of important implications in the field of pharmacotherapy. Oral colon targeted drug delivery systems have recently gained importance for delivering a variety of therapeutic agents for both local and systemic administration. Targeting of drugs to the colon via oral administration protect the drug from degradation or release in the stomach and small intestine. It also ensures abrupt or controlled release of the drug in the proximal colon. Various drug delivery systems have been designed that deliver the drug quantitatively to the colon and then trigger the release of drug. This review will cover different types of polymers which can be used in formulation of colon targeted drug delivery systems.     

An updated review of folate-functionalized nanocarriers: A promising ligand in cancer

The uncontrolled release of drugs in conventional drug delivery systems has led to the introduction of new nanotechnology-based drug delivery systems and the use of targeted nanocarriers for cancer treatment. These targeted nanocarriers, which consist of intelligent nanoparticles modified with targeting ligands, can deliver drugs to specified locations at the right time and reduce drug doses to prevent side effects. Folate is a suitable targeting ligand for folate receptors overexpressed on cancer cells and has shown promising results in the diagnosis and treatment of cancer. In this review, we highlight the latest developments on the use of folate-conjugated nanoparticles in cancer diagnosis and treatment. Moreover, the toxicity, biocompatibility and efficacy of these nanocarriers are discussed.     

Use of prebiotics in oral delivery of bioactive compounds: a nanotechnology perspective

The oral route is considered the most patient-convenient means of drug administration. In recent years there has been a tendency to employ smart carrier systems that enable controlled or timed release of a bioactive material, thereby providing a better dosing pattern and minimizing side effects. Nano-encapsulation systems (nanocarriers) offer important advantages over conventional drug delivery techniques. Nanocarriers can protect the drug from chemical/enzymatic degradation and enhance bioavailability. Prebiotics are ideal ingredients for the nano-encapsulation and oral drug delivery due to their natural ability to protect the encapsulated compound in the upper gasterointestinal (GI) tract. Here the potential of prebiotics for oral delivery of drugs and other bioactives is reviewed.     

Raman microscopy for noninvasive imaging of pharmaceutical nanocarriers: intracellular distribution of cationic liposomes of different composition

Nanotechnology is playing an increasing role in targeted drug delivery into pathological tissues. Drug-loaded pharmaceutical nanocarriers can be delivered into diseased sites by passive targeting (spontaneous accumulation of nanocarriers in the areas with affected vasculature) or by active targeting (via site-specific ligands attached to the surface of drug-loaded nanocarriers). Subsequent level of targeting requires cellular internalization of nanocarriers and their specific association with certain individual cell organelles. The control over intracellular distribution of pharmaceutical nanocarriers requires effective and noninvasive methods of their visualization inside cells. In an attempt to enhance cellular internalization of pharmaceutical nanocarriers and their association with mitochondria specifically, we have prepared three types of cationic liposomes and investigated their intracellular distribution. The analysis was performed using Raman microspectroscopy in order to provide morphological information as well as biochemical signatures of the sample. It was demonstrated that Raman microscopy allows evaluation of the extent of mitochondrial association depending on the liposome composition.     

口服结肠释药系统的研究进展

目的:综述近年来口服结肠释药系统临床和药学研究动态,为今后在此领域的研究和临床应用提供参考。方法:通过对国内外相关文献资料的整理,对比和分析,总结口服结肠释药系统制剂进展和临床应用的发展方向。结果结论:口服结肠释药系统是通过口服给药,在结肠处定位释放药物的靶向制剂。此类制剂以其靶向释药方式和独特的临床使用价值,越来越广泛地引起了临床医生的关注,同时也成为药学研究领域的一大热点。