聚乙烯醇衍生物作为水凝胶材料的应用研究进展

目的介绍PVA衍生物作为水凝胶材料的应用研究进展,为进一步开发它提供依据和参考。方法参阅近年来国内外相关文献资料,对其进行综合、分析和归纳。结果 PVA水凝胶具有亲水性、柔软性、温和性和良好的生物相容性,其衍生物作为普通水凝胶和智能水凝胶材料被广泛应用于生物医药学领域。结论 PVA是一种极具再次开发潜力的优良药用辅料,具有很大的应用价值。     

刺激响应型DNA水凝胶及其在生物传感和药物控释方面的应用

目的介绍近年发展起来的刺激响应型DNA水凝胶的研究进展。方法参考近年来发表的文献共31篇,根据外界的刺激方式的不同将DNA水凝胶进行分类并对其应用进展进行了介绍和评述。结果 DNA水凝胶可以根据不同的外部刺激做出响应,如pH、温度、光照、配体分子等,并介绍了DNA水凝胶在生物传感和药物控释中的应用进展。结论刺激响应型DNA水凝胶作为一种新型的智能水凝胶,在快速诊断检测,药物传递等生物医学及药学领域展现了良好的应用前景。     

温敏水凝胶在药物缓控释技术中的应用

温敏水凝胶是近几年来发展比较快的一种高分子材料,属于智能水凝胶的一种。虽然迄今为止多数仍停留在实验研究阶段,但可以预见该类水凝胶在医学、农学、生物学等研究领域都有着广阔的应用前景。目前在药物控制释放、组织工程以及生物免疫等多个领域备受关注。本文结合近年来国内外对温敏水凝胶的研究报道,主要介绍了温敏水凝胶的性质及其在药物缓控释中的应用,包括其在药物缓控释制剂中应用的优点、适用的药物类型以及存在的问题等。     

“智能”水凝胶研究进展及其在医药与生物工程中的应用

“智能”高分子水凝胶是一类对于外界环境微小的物理和化学刺激 (如 :温度、pH等 ) ,其自身性质会发生明显改变的聚合物 ,具有传感、处理和执行功能。本文综述了“智能”高分子水凝胶的各种类型、研究进展以及它们在医药与生物工程中的应用和良好的发展前景。     

自愈型水凝胶制备原理及应用于组织工程产品中的现状

目的：考察自愈型水凝胶的生产及应用现状,并探讨其在医疗器械领域的应用前景,为开展下一步的研究工作提供参考。方法：通过查阅近年的文献资料,总结自愈型水凝胶包含的不同结构单元的性质,阐述其实现自愈的原理,以及应用于组织工程产品的研究进展,并对其在生物医药领域的应用进行展望。结果与结论：自愈型水凝胶具有良好的自修复性、可降解性及生物相容性,但力学性能不足等问题限制了其在临床中使用。在未来的研究中,通过对结构改性解决现存问题,自愈型水凝胶会在医疗器械领域中具有很好的应用前景。     

水凝胶递药系统的研究进展及应用

水凝胶是一种具有优异亲水性、柔韧性、溶胀特性的三维网状空间结构聚合物。由于良好的载药特性，水凝胶在药物递送、诊断、治疗、组织工程等领域应用广泛。该研究总结了国内外有关水凝胶的近期文献，就水凝胶的分类、材料及性能改进、水凝胶的形成机制与交联剂等方面进行了综述，并展望水凝胶递药系统的发展前景，以期为相关研究提供参考。     

基于动态共价键的多糖水凝胶在药物递送及组织修复中的应用研究进展

水凝胶具有良好的生物相容性和生物降解性,广泛应用于药物递送、伤口敷料和组织工程等生物医学领域。按照材料来源可分为合成材料水凝胶和天然材料水凝胶,其中天然多糖水凝胶不仅可以作为材料应用,还具有独特的药理活性和较好的机械性能,逐渐成为首选材料。动态共价键水凝胶由于其结构灵活性、自愈合性能和环境响应性备受关注。本文对采用动态键方式的天然多糖水凝胶体系进行归类和总结,并对该类水凝胶在药物递送以及组织修复方面的研究现状进行概述,以期为新型多糖水凝胶的临床应用提供借鉴。     

智能水凝胶在脉冲控释制剂中的应用

智能水凝胶是一种新型功能高分子材料,在药物脉冲控释方面具有智能化、可自调式化和安全等优点,在药物脉冲控释方面有广泛应用前景。本文综述了温度、葡萄糖、pH值、磁场及电场敏感水凝胶的响应原理及在脉冲控释制剂中的最新应用。     

凝胶控释注射给药系统研究进展

此文综述了可注射高分子水凝胶在药物控释领域的研究进展,主要包括天然、半天然以及人工合成的高分子水凝胶,重点介绍了两类研究比较深入的水凝胶-壳聚糖水凝胶和泊洛沙姆水凝胶。     

温敏在体凝胶给药系统的研究与应用

综述N-异丙基丙烯酰胺类聚合物、聚氧乙烯-聚氧丙烯共聚物、聚氧乙烯-聚乳酸羟基乙酸共聚物和多糖类衍生物等温敏聚合物的性质、特点、胶凝机制及在温敏在体凝胶给药系统中的应用进展。温敏在体凝胶作为一种智能水凝胶,可用作药物缓、控释和靶向输送的有效载体。     

新型药物凝胶剂研究进展

新型药物凝胶剂是近年来兴起的一种新剂型,其在医药领域的应用研究逐渐引起关注。笔者概述其几种常见类型,如智能型水凝胶剂、脂质体凝胶剂、包合物凝胶剂,望为这方面的研究提供参考。     

Development of smart delivery system for ascorbic acid using pH-responsive P(MAA-co-EGMA) hydrogel microparticles

pH-Responsive P(MAA-co-EGMA) hydrogel microparticles were prepared and their feasibility as intelligent delivery carriers was evaluated. P(MAA-co-EGMA) hydrogel microparticles were synthesized via dispersion photopolymerization. There was a drastic change in the swelling ratio of P(MAA-co-EGMA) microparticles at a pH of ~ 5 and, as the amount of MAA in the hydrogel increased, the swelling ratio increased at a pH above 5. The loading efficiency of the ascorbic acid into the hydrogel was affected more by the degree of swelling of the hydrogel than the electrostatic interaction between the hydrogel and the loaded ascorbic acid. The P(MAA-co-EGMA) hydrogel microparticles showed a pH-sensitive release behavior. Thus, at pH 4 almost none of the ascorbic acid permeated through the skin while at pH 6 relatively high skin permeability was obtained. The ascorbic acid loaded in the hydrogel particles was hardly degraded and its stability was maintained at high temperature.     

Intelligent hydrogels for drug delivery system

Intelligent hydrogel, also known as smart hydrogels, are materials with great potential for development in drug delivery system. Intelligent hydrogel also has the ability to perceive as a signal structure change and stimulation. The review introduces the temperature-, pH-, electric signal-, biochemical molecule-, light- and pressure- sensitive hydrogels. Finally, we described the application of intelligent hydrogel in drug delivery system and the recent patents involved for hydrogel in drug delivery.     

Postfabrication encapsulation of model protein drugs in a negatively thermosensitive hydrogel

A postfabrication encapsulation technique was developed for loading model protein drugs into an intelligent and biodegradable hydrogel film, which exhibits negative thermosensitivity with a desirable phase transition temperature between refrigerator temperature and body temperature. The hydrogel comprises mainly poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymer, and oligo(lactide). The model proteins Hemoglobin and Bovine Serum Albumin were loaded into the hydrogel films by soaking the gels at 4 degrees C, at which the hydrogel film was swollen. The loaded drug was released gradually in PBS at 37 degrees C, where the hydrogel film was shrunken. Because the hydrogel is biodegradable, the loaded drug could be released completely. It is confirmed that proteins can, in their native structures, be included in the hydrogel via the present technique, as characterized by FTIR, Raman spectrum, UV/VIS spectrum, and circular dichroism spectrum. The highlight of our approach is avoidance of high temperatures and organic solvents in encapsulation, making it ideal for protein drug delivery systems.     

A thermo- and pH-sensitive hydrogel composed of quaternized chitosan/glycerophosphate

The quaternized chitosan was synthesized by the reaction of chitosan and glycidyltrimethylammonium chloride (GTMAC) and named as N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride (HTCC). A novel hydrogel system composed of HTCC/glycerophosphate (HTCC/GP) with thermo- and pH-sensitivity was synthesized and used as an intelligent drug carrier. The formulation was solution below or at room temperature, which allowed it injectable and to incorporate living cells, proteins, enzymes or other therapeutic drugs easily. Once the surrounding temperature was up to 37 degrees C, the system was transformed to a non-flowing hydrogel, and the formed hydrogel can release the trapped drug as a function of pH values. The swelling behavior of the system and the release profiles of doxorubicin hydrochloride (DX) as a model drug at different pH values were investigated. At acidic condition the hydrogel dissolved and released drug quickly, while it absorbed water and released drug slowly at neutral or basic conditions. Hydrogel composed of chitosan hydrochloride and glycerophosphate (CS/GP) was also prepared to compare with HTCC/GP hydrogel. The HTCC/GP hydrogel in this study was transparent which made it suitable for some specific uses such as ocular drug formulation.     

Chitosan-based hydrogels for controlled, localized drug delivery

Hydrogels are high-water content materials prepared from cross-linked polymers that are able to provide sustained, local delivery of a variety of therapeutic agents. Use of the natural polymer, chitosan, as the scaffold material in hydrogels has been highly pursued thanks to the polymer's biocompatibility, low toxicity, and biodegradability. The advanced development of chitosan hydrogels has led to new drug delivery systems that release their payloads under varying environmental stimuli. In addition, thermosensitive hydrogel variants have been developed to form a chitosan hydrogel in situ, precluding the need for surgical implantation. The development of these intelligent drug delivery devices requires a foundation in the chemical and physical characteristics of chitosan-based hydrogels, as well as the therapeutics to be delivered. In this review, we investigate the newest developments in chitosan hydrogel preparation and define the design parameters in the development of physically and chemically cross-linked hydrogels.     

Temperature-sensitive poly(N-isopropylacrylamide)/poly(ethylene glycol) diacrylate hydrogel microspheres

Objective

To develop and characterize a new class of temperature-sensitive hydrogel microspheres composed of poly(N-isopropylacrylamide)/poly(ethylene glycol) diacrylate (PNIPAAm/PEG-DA).

Methods

The PNIPAAm/PEG-DA hydrogel microspheres were fabricated in two aqueous systems as a result of polymer/polymer immiscibility. Both PNIPAAm and PEG-DA were used as the precursors; the PEG-DA was also used as a cross-linker for the formation of the hydrogel microspheres. Bovine serum albumin was used as the model protein drug to examine the effects of the thermo-responsive properties of the hydrogel microspheres on the release of a protein at two different temperatures (22°C and 37°C).

Results

The hydrated PNIPAAm/PEG-DA hydrogel microspheres exhibited a swollen diameter of 50µm, with a narrow particle-size distribution. Scanning electron microscopy and environmental scanning electron microscopy observations revealed that, upon swelling, the resulting hydrogel microspheres had a regular spherical and rough surface morphology. The lower critical solution temperature (LCST) of the PNIPAAm/PEG-DA hydrogel microspheres was around 29.1°C, based on differential scanning calorimetric data. The release of BSA from the hydrogel microspheres at 37°C was slower than that at 22°C because of the thermo-responsive nature of PNIPAAm at temperatures above its LCST.

Conclusions

We believe that these kinds of PNIPAAm/PEG-DA hydrogel microspheres may have wide applications as promising drug delivery systems, because of their intelligent nature upon external temperature change.     

嵌段共聚物OSM1-PCLA-PEG-PCLA-OSM1的pH和温度敏感性质及体外释药特性考察

目的 为嵌段共聚物磺胺甲嘧啶低聚物-聚-ε-己内酯-丙交酯-聚乙二醇-聚-ε-己内酯-丙交酯-磺胺甲嘧啶低聚物（sulfamerazine oligomers-poly(ε-caprolactone-co-DL-lactide-b-ethyleneglycol-b-ε-caprolactone-co-DL-lactide)-sulfamerazine oligomers,OSM₁-PCLA-PEG-PCLA-OSM1)作为缓控释给药系统的载体提供依据。方法 采用激光粒度仪对不同pH和温度下嵌段共聚物OSM₁-PCLA-PEG-PCLA-OSM₁胶束粒径大小、分布进行考察;通过表面张力和相转变温度测定对其临界胶束浓度和溶液-凝胶相转变行为进行考察;以5-氟尿嘧啶为模型药,通过透射电镜观察载药和空白共聚物胶束形态;采用物理混合法制备5-氟尿嘧啶载药水凝胶;采用HPLC法测定载药水凝胶中药物释放速率。结果 嵌段共聚物OSM₁-PCLA-PEG-PCLA-OSM₁胶束溶液具有pH和温度双重敏感的性质,在一定pH和温度条件下可发生溶液-凝胶相转变;5-氟尿嘧啶载药水凝胶体外释放可持续9 d,具有较好的缓释作用。结论 pH和温度双重敏感型嵌段共聚物OSM₁-PCLA-PEG-PCLA-OSM₁作为注射缓释给药系统载体材料具有良好的应用前景。     

Characterization of pH- and Thermosensitive Hydrogel as a Vehicle for Controlled Protein Delivery

N-[(2-Hydroxy-3-trimethylammonium)propyl] chitosan chloride (HTCC) was chemically modified using glycidyltrimethylammonium chloride (GTMAC). A new composite hydrogel was prepared using the mixture of HTCC and α-β-glycerophosphate (α-β-GP). The gelation of HTCC/GP mainly depended on the concentration and proportion of HTCC and GP. Thermogravimetric analysis exhibited high stability of HTCC/GP hydrogels. Surface morphology assay demonstrated that HTCC/GP hydrogels were well constructed with three-dimensional (3D) porous structures in the range of 5 of 40 μm. The insulin was entrapped during the formation of hydrogel. In vitro, the insulin release was controlled by modifying the composition, drug loading, and pH condition. The hydrogel dissolved and released drug quickly under acidic condition, whereas it absorbed water and released drug slowly under neutral or basic conditions. The hydrogels were biocompatible, and the cells could adhere to and then migrated to the hydrogels. Furthermore, these cells were viable and retained 3D morphology inside the hydrogels. Interestingly, HTCC/GP hydrogel showed both thermo- and pH-sensitive properties. There are potential applications in tissue engineering, cell encapsulation, and intelligent drug delivery systems.