水凝胶在青光眼缓控释递药中的研究进展

青光眼严重影响正常视觉功能,但目前药物治疗效率低下。眼部缓控释制剂可以延长药物作用时间,减少给药次数,提高患者顺应性。水凝胶是一类在眼科中用途极其广泛的材料,预制凝胶和原位凝胶在眼科药物的缓控释递送中显示出极大潜力。以接触镜为代表的预制凝胶则可提供持续的药物释放和眼前滞留。原位凝胶兼具溶液剂给药方便和凝胶剂延缓释药的优势。本文就近几年不同给药途径中将水凝胶应用于抗青光眼药物缓控释研究中的进展进行归纳和总结,并讨论水凝胶在青光眼的治疗中存在的挑战,希望能为其临床使用提供参考。     

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。     

局部药用凝胶剂的研究新进展和新应用

凝胶剂（Gel）是指药物与能形成凝胶剂的辅料制成的均一、混悬或乳剂型的乳胶稠厚液体或半固体制剂.凝胶剂作为新型的药物制剂,广泛用于缓释、控释及脉冲释放等新型给药系统,可分为全身用凝胶剂和局部用凝胶剂两类.     

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。     

体外蔗糖聚酯基质的水杨酸钠释放

水凝胶在药物控释方面有潜在的用途,已研究过它的抗生素、类固醇、无机氟化物、抗肿瘤药和麻醉性拮抗剂的给药系统以及眼科的应用。在控释药物给药系统的发展中,释放速率按零级动力学进行是特别重要的。只有这种方法,才能保证给药装置的最佳性能和效果。本文目的是检验田蔗糖聚酯制备的贮库     

阿莫西林脉冲释药微丸的研制

目的:制备阿莫西林脉冲释药微丸。方法:取空白丸芯分别以含药层、溶胀层(羧甲基淀粉钠)和控释层(乙基纤维素水分散体)顺序依次进行包衣制备阿莫西林脉冲释药微丸。采用紫外法和篮法考察溶胀层(12%、16%、20%)和控释层包衣增重(24%、28%、32%)及不同介质(水、盐酸、pH6.8磷酸盐缓冲液)对药物释放的影响。结果:溶胀层和控释层包衣增重对脉冲控释微丸的释药时滞和释放速率具有显著影响,药物释放情况不受介质pH值的影响;溶胀层和控释层包衣增重分别为16%、28%时制备的微丸时滞时间约为4h,时滞后4h累积释药率达到80%。结论:所制备的阿莫西林脉冲释药微丸具有体外脉冲释放作用。     

新型凝胶给药系统研究进展

凝胶在现代药学中应用广泛,以凝胶为基质的缓释控释剂型,如胃滞留控释系统、凝胶骨架片等,得到了全面的研究。适用于凝胶给药系统的药物甚多,亲水性药物、疏水性药物、酸性药物、阳离子药物、大分子药物、细胞组织等均可作为它的模型药物。而且可以从口腔、鼻腔、眼粘膜、消化道粘膜、阴道、直肠、皮肤等途径给药。     

微凝胶的制备及其在药物缓控释系统中的应用

微凝胶是一种具有分子内交联网状结构,粒径在0.1~100 μm之间的功能性聚合物,具有粒径小、载药量高、环境响应性灵敏、生物相容性好等特点,在药物缓控释系统中的应用具有独特优势。笔者在查阅近年国内外文献的基础上综述了微凝胶的基本特性、制备方法、制备材料及在药物缓控释系统中的应用。     

Hydrogels: from controlled release to pH-responsive drug delivery

Hydrogels are one of the upcoming classes of polymer-based controlled-release drug delivery systems. Besides exhibiting swelling-controlled drug release, hydrogels also show stimuli-responsive changes in their structural network and hence, the drug release. Because of large variations in physiological pH at various body sites in normal as well as pathological conditions, pH-responsive polymeric networks have been extensively studied. This review highlights the use of hydrogels (a class of polymeric systems) in controlled drug delivery, and their application in stimuli-responsive, especially pH-responsive, drug release.     

5-Fluorouracil in topical liposome gels for anticancer treatment--formulation and evaluation

Liposome gels bearing an antineoplastic agent, 5-fluorouracil, intended for topical application have been prepared and drug release properties in vitro have been evaluated. Different formulations of liposomes were prepared by the film hydration method by varying the lipid phase composition (PL 90H/cholesterol mass ratio) and hydration conditions of dry lipid film (drug/aqueous phase mass ratio). Topical liposome gels were prepared by incorporation of lyophilized liposomes into a structured vehicle (1%, m/m, chitosan gel base). Also, hydrogels containing different concentrations of 5-fluorouracil were prepared and drug release properties were investigated. The rate of drug release from liposome gels was found to be dependent on the bilayer composition and the dry lipid film hydration conditions. Also, liposomes embedded into a structured vehicle of chitosan showed significantly slower release than hydrogels. The drug release obeyed the Higuchi diffusion model, while liposomes acted as reservoir systems for continuous delivery of the encapsulated drug.     

Hydrogels: properties and application in the technology of drug form. II. Possibilities of use of hydrogels as active substance carriers

In first unit of running was described the properties, method the obtention and kinds sensitive on factors such how the temperature, pH, the electrolytes, the chosen substances, light, of hydrogels and hydrogel delivery systems. The following study is a review of literature related to application of hydrogel as healing substances carriers, possibility of application of hydrogels in oral, applied on skin and the rectal, vaginal systems of release, applied on nasal as well as passed to eyes and parenteral. The utilization the hydrogels in construction the new systems of release the substance allows to remain the aspect ratio time of substance at the application place, the obtainment of prolonged release the medicine, by parallel of applied dose and the system undesirable effects. The hydrogels on the basis of were received the form of medicine about controlled release the substance, bioadhesive drug carriers as well targetable devices of therapeutic agents.     

pH敏感型羧甲基壳聚糖水凝胶的制备及体外释药考察

目的:研制一种新型羧甲基壳聚糖基pH敏感性水凝胶,考察其在药物传输体系中的应用.方法:采用钙离子交联方法制备有良好pH响应性能的羧甲基壳聚糖基水凝胶,并对其pH响应性能进行相关的表征.以磺胺嘧啶钠为模型药物,考察载药水凝胶在不同pH环境条件下(pH =2和pH =7.4)的药物释放行为.结果:所制备的羧甲基壳聚糖水凝胶具有明显的孔洞结构和良好的pH响应性能,在中性磷酸盐缓冲溶液(pH=7.4)中吸水率显著大于在酸性溶液(pH=2)中的吸水率.载有磺胺嘧啶钠的羧甲基壳聚糖水凝胶在中性磷酸盐缓冲溶液(pH=7.4)中的4h的药物累计释放率达到95％,而在酸性溶液(pH=2)中的4h的药物累计释放率却只有50％.结论:本文所制备的羧甲基壳聚糖pH敏感性水凝胶具有良好的孔隙率和pH响应性能,在口服药物传输体系中有一定的应用前景.     

Release of theophylline from polymer blend hydrogels

Polymer blending is a simple yet attractive method to obtain combined physical and mechanical properties of polymers. In this paper, three types of blend hydrogels were prepared, each by physically blending two different natural polymers, and a model drug, theophylline (TPH), was immobilized into these hydrogels for the studies of drug release. The release profiles of TPH from various types of hydrogels were determined by UV-vis absorption measurement at 272 nm. The experimental results show that the releases of TPH from these hydrogels are dependent upon the composition of the hydrogel, the type of component, the possible interactions between two component polymers, as well as external temperature. All the release profiles clearly demonstrate a temperature effect. Among the three blend hydrogels, the slowest release was observed from the blend hydrogel of gelatin and agar with a weight ratio of 1:1. The drug release patterns and release mechanisms have been discussed by considering the possible molecular interactions and gel network structures.     

Dexamethasone sodium phosphate-loaded Chitosan based delivery systems for buccal application

Chitosan (CH) was used as a biocompatible and bioadhesive polymer material to prepare solid dispersions as well as hydrogels loaded with dexamethasone sodium phosphate (DSP), a steroidal anti-inflammatory agent clinically used for treatment of different mouth diseases. Binary solid dispersions at various drug-to-polymer weight ratios were prepared by freeze-drying; their direct compression gave tablets which were characterized for the swelling behaviour and drug release in vitro. Similarly, DSP-loaded hydrogels composed of CH and glycerine were prepared and characterized. CH and DSP showed a good physical compatibility. A slow and prolonged release of the drug was observed in vitro from both kinds of systems. The swelling properties of the polymer seemed to be the main parameter affecting the drug release profile from both tablets and hydrogels at the pH value of mouth. In vivo buccal application of both the systems allowed to obtain a prolonged release of DSP, as compared with a glycerine solution of the drug. From the in vitro swelling studies and in vivo test, the 2:1 CH-DSP solid dispersion in particular can be designated for further investigation.     

Surface crosslinking for delayed release of proxyphylline from PHEMA hydrogels

Delayed release systems find applications in chronotherapeutics and colon-specific delivery. They have also been considered suitable carriers for the oral delivery of peptides and proteins. In prior work, our research group has reported surface crosslinking as an effective technique to modify drug release profiles for poly(vinyl alcohol) (PVA) hydrogels, reducing the early burst effect in particular. Here, we demonstrate the feasibility of delayed release of proxyphylline from poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels via surface crosslinking. Studies on in vitro drug release and the morphology changes of PHEMA hydrogels during swelling and drug release showed that the highly surface crosslinked layers and the ruptures occurring in these layers during swelling were likely responsible for the delayed release. In addition, the initial burst was significantly reduced or even eliminated from the drug release profile for PHEMA to achieve near zero-order release by judicious selection of two surface crosslinking parameters: crosslinking reagent concentration and exposure time used for the surface crosslinking treatment.     

Slow release of two antibiotics of veterinary interest from PVA hydrogels

Two antibiotics, tylosin tartrate and oxytetracycline hydrochloride, were entrapped in poly(vinyl alcohol) (PVA) hydrogels (MW 31,000-50,000) by a cryogen procedure obtaining a controlled release system suitable for veterinary application. It was found that at a low drug matrix loading (10 mg/ml), the in vitro release rate of both antibiotics could be reduced by a previous freeze drying of the gel, while no reduction in drug rate took place in heavily loaded matrices (300 mg/ml). When PVA hydrogels containing tylosin were administered to rats per os the drug could not be detected in the blood, but it was found in organs,: liver, kidneys, and muscles, for up to 120 h. On the other hand, when the same amount of drug was administered orally as powder, no appreciable organ accumulation was detected, while the drug was found in faeces and urine. These data show that PVA hydrogels can be a suitable slow release system for tylosin administration. Oxytetracycline could also be quantitatively entrapped and released from PVA hydrogels, but once administered per os to rats, it was not detected in blood or organs.     

一种pH敏感水凝胶的性质及用于胰岛素口服给药的研究

目的研究pH敏感水凝胶的性质及其用于胰岛素口服给药的降血糖作用。方法制备了聚(甲基丙烯酸 泊洛沙姆 )共聚物水凝胶 ;在不同pH值的介质中研究凝胶溶胀、药物扩散和药物释放性质 ;含胰岛素的凝胶经口服给予糖尿病大鼠。结果水凝胶具有 pH敏感的性质 ;糖尿病大鼠口服给予含胰岛素的聚合物后有明显的剂量依赖的降血糖作用。结论这种水凝胶有望用作药物传递的载体。     

Chitosan glutamate hydrogels with local anesthetic activity for buccal application

Hydrogels for the buccal application of the anesthetic drug lidocaine hydrochloride (LDC) were prepared using chitosan glutamate (CHG), a soluble salt of chitosan, or a binary mixture of CHG and glycerin, at different weight ratios. The in vitro drug release was studied at the pH value of saliva to assess the effect of the different formulations on drug delivery. The anesthetic activity of mucoadhesive LDC-CHG hydrogels was assessed in vivo after application on the buccal mucosa, compared to commercial semisolid formulations containing the same drug. LDC-loaded hydrogels can be proposed for the symptom relief of aphthosis or other painful mouth diseases.