小分子自组装纳米递药系统研究进展

生物纳米技术在药物递送领域的应用为高端创新制剂的研发注入了新动力,一系列新型纳米递药系统被相继开发乃至应用于临床。其中,由小分子药物或前药自组装形成的纳米递药系统因具有制备工艺简便、载药量超高和易于实现工业化生产等优势而备受关注,已成为纳米递药系统领域的一个重要分支。本文总结了小分子自组装纳米递药系统的最新研究进展。首先,对小分子前药自组装纳米递药系统进行介绍,包括两亲性、疏水性和二聚体小分子前药自组装纳米递药系统。其次,分别介绍小分子化学药物和小分子生物药物自组装纳米递药系统的最新进展。再者,对小分子杂化共组装纳米递药系统进行总结和分析,包括小分子纯药共组装纳米递药系统、小分子前药共组装纳米递药系统及小分子前药/小分子纯药共组装纳米递药系统。最后,讨论了小分子自组装纳米递药系统的合理设计、应用前景和临床挑战,以期为新一代纳米制剂的设计与构建提供参考。     

介孔二氧化硅纳米粒介导的药物传递系统及其生物安全性的研究进展

介孔二氧化硅纳米粒(MSNs)是一种新型无机纳米材料,因具有独特的网状孔道结构、巨大的比表面积、孔径分布窄且可调节及易于表面修饰等特性,已用于药物控释系统的研究.MSNs载体的药物负载量与其介孔容积相关,表面经修饰后可实现药物的控释和靶向传递.然而,随着MSNs载体与人体接触的机会和时间日益增加,其安全性也受到广泛关注.本文综合近10年来国内外的相关文献,归纳了MSNs在递药系统中的应用,并分析了其生物安全性的影响因素.     

药用高分子在缓控释制剂中的应用现状

<正>缓控释制剂的发展除与制药设备的不断发展、革新有关外,药用高分子在该类制剂中也是不可分割的重要组成部分。近年来,一些新型高分子材料的研究和应用使缓控释制剂步入了定时、定向、定位、速效、高效、长效的精密化给药阶段,出现了口服渗透泵控释制剂、脉冲式释药系统、环境敏感型定位释药系统、结肠定位给药系统等新型缓控释制剂。辅料的成分、组成与结构对药物的释放性能有很大的影响,因此在缓控释制剂中合理应用新型高分子材料,就具有重要的意义。1药用高分子作为药物载体药用高分子的广泛研究和应用,促进了缓控释制剂的快     

脂微球载药系统的研究进展

脂微球递药系统是药剂学研究的热点,从脂微球载药系统的形成机制、构建方法及关键影响因素等方面进行综述,介绍该领域研究的进展和一些新发现,以促进脂微球作为药物载体的开发和应用。     

口服渗透泵药物传递系统

渗透泵递药系统由于其可靠性和可以长时间在预定的时间内按零级速率释放药物的性能,是最有效的药物控释系统。此类递药系统基于渗透压控制有效成分的释放。在很大程度上,这些系统中的药物传递释放不受胃肠道生理因素影响。本文简要讨论了口服渗透泵片剂的基本成分,关键的处方因素和不同类型的渗透泵控释系统。     

聚乙二醇修饰脂质小分子在胶束给药系统中的研究进展

脂质分子因具有无毒性,无免疫源性以及良好的生物兼容性,广泛应用于药物载体研究中。经聚乙二醇修饰的脂质具有双亲性,在水中可自组装形成胶束。该类聚合物载体能够增强药物的溶解度及稳定性,改善药物在体内的药动学行为,增强疗效等,在纳米给药系统中具有广阔的应用前景。本文综述了在胶束给药系统中应用较多的聚乙二醇化脂质小分子,主要包括聚乙二醇修饰的磷脂,胆固醇,脂肪酸等。     

药物缓控释制剂的研究概况

缓控释制剂是指在水中或某些特殊介质中缓慢释放药物的制剂,可适用于多种给药途径,制作成多种药用剂型。缓控释制剂作为一种特殊释药系统一直在药剂专业范围内被广泛关注。本文就缓控释制剂的载体材料及剂型进行概述。     

生物可降解聚合物及其在药物纳米控释系统中的应用

目的：介绍生物可降解聚合物及其在药物纳米控释系统中的应用。方法：查阅可降解聚合物及其在药物纳米控释系统中应用研究的国内外献。结果：医用纳米控释系统作为药物的载体具有很多优点，如它可通过组织间隙并被细胞吸收，可通过人体最小的毛细血管，具有明显的药物缓释效果及较小的不良反应，因而作为新的控释系统而被广泛研究。结论：生物可降解聚合物在药物纳米控释系统中的应用具有广阔的发展前景。     

多囊脂质体在递药系统中的应用研究进展

目的:为多囊脂质体在递药系统中的应用提供参考。方法:以"多囊脂质体""multivesicular liposomes"等为关键词,在中国知网、Pub Med等数据库中查阅1983-2013年的相关文献,对多囊脂质体作为药物载体在递药系统的研究情况进行归纳与总结。结果与结论:共查询到文献609篇,其中有效文献20篇。经分析表明,多囊脂质体为非同心腔室构成的新型脂质体,包封率高,可多途径给药,且具有良好的缓释作用,目前已在抗肿瘤药物、镇痛药物、抗菌药物、抗病毒药物和蛋白质多肽药物上广泛运用。但如今多囊脂质体在稳定性、贮存和运输等方面仍存在一些问题,相信随着对多囊脂质体研究的深入,其必将在递药系统中得到更广泛的运用。     

离子交换树脂在药剂学中的应用进展

离子交换树脂药物载体在给药系统中的应用由于具有很多优点而得到了人们的重视。目前在控释、透皮给药、定位给药、速溶、离子导入透皮、鼻腔、局部给药和掩盖药物苦味等方面都有很深入的研究，在缓控释给药中占有特殊的地位。综述了这一药物载体在给药系统和作用部位应用的新进展，并对其应用前景进行了展望。     

Functional multilayered capsules for targeting and local drug delivery

One of the key challenges in the field of bio-nanotechnology for drug delivery systems (DDS) is the development of nano- or micro-sized delivery carriers possessing both targeting functionalities for specific tissues or cells, and controlled release properties for encapsulated drug molecules, proteins and genes. Hollow capsules developed by layer-by-layer (LbL) assembly have attracted much attention over the past few years owing to their ability to be modified, their capacity to encapsulate a wide range of chemicals, and the variety of functionalities with which they can be enhanced. Current research on LbL capsules focuses on the development of functionalized capsules for specific targeting of cancer or immune cells, and on controlling their release properties by environmental stimuli. This review discusses recent advances in DDS using functional hollow capsules specific for the cellular and tissue-targeted delivery, as well as stimuli-responsive controlled release. DDS based on functional hollow capsules may contribute to the development of new nano-medicines.     

pH- and sugar-sensitive layer-by-layer films and microcapsules for drug delivery

The present review provides an overview on the recent progress in the development of pH- and sugar-sensitive layer-by-layer (LbL) thin films and microcapsules in relation to their potential applications in drug delivery. pH-sensitive LbL films and microcapsules have been studied for the development of peptide and protein drug delivery systems to the gastrointestinal tract, anti-cancer drugs to tumor cells, anti-inflammatory drugs to inflamed tissues, and the intracellular delivery of DNA, where pH is shifted from neutral to acidic. pH-induced decomposition or permeability changes of LbL films and microcapsules form the basis for the pH-sensitive release of drugs. Sugar-sensitive LbL films and microcapsules have been studied mainly for the development of an artificial pancreas that can release insulin in response to the presence of glucose. Therefore, glucose oxidase, lectin, and phenylboronic acid have been used for the construction of glucose-sensitive LbL films and microcapsules. LbL film-coated islet cells are also candidates for an artificial pancreas. An artificial pancreas would make a significant contribution to improving the quality of life of diabetic patients by replacing repeated subcutaneous insulin injections.     

Emerging trend in nano-engineered polyelectrolyte-based surrogate carriers for delivery of bioactives

Importance of the field: In recent decades a new colloidal drug delivery system based on layer-by-layer (LbL) technology has emerged, which offers promising means of delivering bioactive agents, specifically biological macromolecules including peptides and DNA. Nano-engineered capsules specifically fabricated from biocompatible and biodegradable polyelectrolytes (PEs) can provide a better option for encapsulation of cells thereby protecting cells from immunological molecules in the body, and their selective permeability can ensure the survival of encapsulated cells.

Areas covered in this review: This review encompasses a strategic approach to fabricate nano-engineered microcapsules through meticulous selection of polyelectrolytes and core materials based on LbL technology. The content of the article provides evidence for its wide array of applications in medical therapeutics, as indicated by the quantity of research and patents in this area. Recent developments and approaches for tuning drug release, biocompatibility and cellular interaction are discussed thoroughly.

What the reader will gain: This review aims to provide an overview on the development of LbL capsules with specific orientation towards drug and macromolecular delivery and its integration with other drug delivery systems, such as liposomes.

Take home message: Selection of PEs for the fabrication of LbL microcapsules has a profound effect on stability, drug release, biocompatibility and encapsulation efficacy. The release can be easily modulated by varying different physicochemical as well as physiological conditions. Scale-up approaches for the fabrication of LbL microcapsules by means of automation must be considered to improve the possibility of application of LbL microcapsules on a large scale.     

Layer-by-Layer assembled nano-drug delivery systems for cancer treatment

Nano-drug delivery systems (NDDS) are functional drug-loaded nanocarriers widely applied in cancer therapy. Recently, layer-by-layer (LbL) assembled NDDS have been demonstrated as one of the most promising platforms in delivery of anticancer therapeutics. Here, a brief review of the LbL assembled NDDS for cancer treatment is presented. The fundamentals of the LbL assembled NDDS are first interpreted with an emphasis on the formation mechanisms. Afterwards, the tailored encapsulation of anticancer therapeutics in LbL assembled NDDS are summarized. The state-of-art targeted delivery of LbL assembled NDDS, with special attention to the elaborately control over the passive and active targeting delivery, are represented. Then the controlled release of LbL assembled NDDS with various stimulus responsiveness are systematically reviewed. Finally, conclusions and perspectives on further advancing the LbL assembled NDDS toward more powerful and versatile platforms for cancer therapy are discussed.     

Modulating the release kinetics through the control of the permeability of the layer-by-layer assembly: a review

The layer-by-layer (LbL) self-assembly technique has emerged as a simple and versatile method for coating biological and non-biological templates for various biomedical applications. A promising avenue of this technique lies in the encapsulation of drugs and other biological substances for controlled release. Fundamental studies of LbL assembly on flat surfaces have provided a sound understanding of film deposition theory and its pertinence to ionic and molecular transport and diffusion through polyelectrolyte multilayer (PEM) films. However, there is a lack of information on the permeability of three-dimensional PEM shell systems. In either PEM films or shells, it has been shown that drug release is a function of the ionic strength, pH and/or multilayer thickness. This report aims to provide an overview of the physicochemical parameters affecting the permeability of two- and three-dimensional multilayer shells, including ionic strength, layer number and pH. Furthermore, their synergic effect on loading and release of biologically active molecules from LbL multilayers are discussed.     

Layer-by-layer capsules for magnetic resonance imaging and drug delivery

Layer-by-layer (LbL) self-assembled polyelectrolyte capsules have demonstrated their unique advantages and capability in drug delivery applications. These ordered micro/nano-structures are also promising candidates as imaging contrast agents for diagnostic and theranostic applications. Magnetic resonance imaging (MRI), one of the most powerful clinical imaging modalities, is moving forward to the molecular imaging field and requires the availability of advanced imaging probes. In this review, we are focusing on the design of MRI visible LbL capsules, which incorporate either paramagnetic metal-ligand complexes or superparamagnetic iron oxide (SPIO) nanoparticles. The design criteria cover the topics of probe sensitivity, biosafety, long-circulation property, targeting ligand decoration, and drug loading strategies. Examples of MRI visible LbL capsules with paramagnetic or superparamagnetic moieties were given and discussed. This carrier platform can also be chosen for other imaging modalities.     

Controlled Release of Dexamethasone from Microcapsules Produced by Polyelectrolyte Layer-by-Layer Nanoassembly

Purpose. In an effort to expand the application of core-shell structures fabricated by electrostatic layer-by-layer (LbL) self-assembling for drug delivery, this study reports the controlled release of dexamethasone from microcrystals encapsulated with a polyelectrolyte shell.Methods. The LbL self-assembly process was used to produce dexamethasone particles encapsulated with up to five double layers formed by alternating the adsorption of positively charged poly(dimethyldiallyl ammonium chloride), negatively charged sodium poly(styrenesulfonate) and depending on the pH positively or negatively charged gelatin A or B onto the surface of the negatively charged dexamethasone particles. The nano-thin shells were characterized by quartz crystal microbalance measurements, microelectrophoresis, microcalorimetry, confocal microscopy, and scanning electron microscopy. In vitro release of dexamethasone from the microcapsules suspended in water or carboxymethylcellulose gels were measured using vertical Franz-type diffusion cells.Results. Sonication of a suspension of negatively charged dexamethasone microcrystals in a solution of PDDA not only reduced aggregation but also reduced the size of the sub-micrometer particles. Assembly of multiple polyelectrolyte layers around these monodispersed cores produced a polyelectrolyte multilayer shell around the drug microcrystals that allowed for controlled release depending on the composition and the number of layers.Conclusions. Direct surface modification of dexamethasone microcrystals via the LbL process produced monodispersed suspensions with diffusion-controlled sustained drug release via the polyelectrolyte multilayer shell.