人工神经网络在药物控释系统研究中的应用

目的介绍人工神经网络在药物控释系统研究中的应用.方法查阅相关文献,总结、归纳国内外人工神经网络在药物控释系统中的应用.结果人工神经网络能优化处方组成和工艺过程,使其在控释片剂、控释微粒以及透皮吸收中得到应用.结论人工神经网络在设计和开发药物控释系统中具有广阔的前景.     

人工神经网络在药物控释系统研究中的应用

目的　介绍人工神经网络在药物控释系统研究中的应用。方法　查阅相关文献,总结、归纳国内外人工神经网络在药物控释系统中的应用。结果　人工神经网络能优化处方组成和工艺过程,使其在控释片剂、控释微粒以及透皮吸收中得到应用。结论　人工神经网络在设计和开发药物控释系统中具有广阔的前景     

可生物降解材料在药物控释系统中的应用

通过对应用较多的7类可生物降解材料(包括聚酯、聚酰胺、聚酸酐、聚磷酸酯、聚原酸酯、聚膦腈及聚丁酸酯)在释药特性、制备方法、靶向性以及毒性等方面进行具体阐述，综述了目前合成可生物降解材料在药物控释系统中的应用现状。     

海藻酸钠在临床的应用

目的：对海藻酸的临床应用的纵深发展之势提起重视。方法：微机检索近几年来海藻酸临床应用的有关文献。结果：海藻酸钠可用于制备控释制剂、用作创作修复材料、治疗返流性食管炎、防治放射性损伤、恢复血容量、降血脂、降血糖、治疗习惯性便秘、增强免疫功能等，对改善水质，净化环境有一定经济价值，海藻酸钠无明显不良反应。结论：海藻酸钠的进一步开发，很有前途。     

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。     

3M药物控释系统

3M药物控释系统是3M公司专门致力于开发和制造透皮给药和吸入给药产品及相关组件的部门,通过确立战略伙伴关系,利用3M公司的专利技术和50年的产品开发经验为各大制药公司和研发机构提供服务。吸入式药物控释系统:50年来,3M在定量吸入式药物控释系统的研发领域一直处于领导者的地位,我们研发了世界上第一个MDI(定量吸入气雾剂)产品(1956年)和第一个不含CFC的MDI产品(1995年)。如今,我们在开发各种类型MDI和DPI(干粉吸入)产品的同时,还提供各种类型的阀门,铝罐和DPI装置。     

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。     

可溶性甲壳素/海藻酸钠交联微球的制备及其表征和控释性能考察

目的制备可溶性甲壳素/海藻酸钠交联微球,表征微球的微观结构和形态。方法利用滴入法制备可溶性甲壳素/海藻酸钠交联微球,用红外光谱和扫描电镜表征微球的微观结构和形态,以牛血清蛋白为药物模型,研究微球的药物缓释性能。结果可溶性甲壳素与海藻酸钠进行了良好的混溶,并且在钙离子（Ca2+）溶剂环境下形成交联微球。该微球对药物的包封率及缓释性能与海藻酸钠微球相比都有较大改善,包封率从42%提高到74%,药物缓释时间从4 h上升到24 h。结论可溶性甲壳素/海藻酸钠微球的释药具有pH响应性,在pH为1.2的条件下释药慢,而在pH为7.0～7.4时释药快,可用于小肠或结肠定位缓释系统。     

药用缓控释辅料海藻酸钠的研究概况

海藻酸钠又称藻酸钠、海草酸钠、褐藻胶（Sodium Alginate，AGS，Algin），分子式为（C6H7O6Na）n，是一种从褐藻类的海带或马尾藻中提取的聚阴离子多糖（海藻酸）的钠盐。自1883年由海带中发现AGS以来，直至1929年开始在美国应用于工业生产，1944年用于食品工业，1983年经美国食品与药品管理局（FDA）批准其可直接作为食品的成分，用于医药工业不过近30年的时间。本文着重对其相关性质及在缓控释制剂方面的应用情况综述如下。     

Electric Current-Sensitive Drug Delivery Systems Using Sodium Alginate/Polyacrylic Acid Composites

Pharmaceutical Research -     

Synthesis and Characterization of Sodium Alginate Conjugate and Study of Effect of Conjugation on Drug Release from Matrix Tablet

The aim of the present research work to study the effect of conjugation of the polymer on drug release from the matrix tablets. Sodium alginate L-cysteine conjugate was achieved by covalent attachment of thiol group of L-cysteine with the primary amino group of sodium alginate through the amide bonds formed by primary amino groups of the sodium alginate and the carboxylic acid group of L-cysteine. The synthesised sodium alginate L-cysteine conjugate was characterised by determining of charring point, Fourier transmission-infrared and differential scanning calorimetric analysis. To study the effect of conjugation on drug release pattern, the matrix tablets were prepared using various proportions of sodium alginate and sodium alginate L-cysteine conjugate along with atorvastatin calcium as model drug. The wet granulation technique was adopted and prepared matrix tablets were evaluated for various physical parameters. The in vitro drug release study results suggested that tablet formulated in combination of sodium alginate and sodium alginate L-cysteine conjugate S4 showed 100% after 8 h drug release whereas formulated with only sodium alginate S0 released 40% in 8 h.     

A Critical Review of Gastric Retentive Controlled Drug Delivery

The promise of gastric retentive drug delivery systems has propagated numerous investigations and the formation of a number of companies. Three technologies have involved a substantial number of human clinical trials: mucoadhesion, density modification, and expansion. Standard, nondisintegrating controlled-release tablets can display significant gastric retention times, with that retention time being proportional to the calorie intake. When these data for standard tablets are factored in, gastric retention technologies do not appear to offer significant additional retention times. Although the goal remains valuable, the promise of gastric retentive drug delivery systems remains unfulfilled at this time.     

Polyanhydride Mierospheres that Display Near-Constant Release of Water-Soluble Model Drug Compounds

A new method to prepare polyanhydride microspheres capable of near-constant sustained release of low molecular weight, water-soluble molecules is presented. The polyanhydrides used were poly-(fatty acid dimer) (PFAD), poly(sebacic acid) (PSA), and their co-polymers [P(FAD-SA)]. Acid orange 63 (AO), acid red 8 (AR), and p-nitroaniline, were used as model release molecules. P(FAD-SA) microspheres containing the molecules with or without gelatin were prepared by a modified solvent evaporation method using a double emulsion. The microspheres were spherical with diameters of 50–125 µm and encapsulated more than 85% of the molecule, irrespective of the compound used. Near-zero-order degradation kinetics were observed for 5 days as judged by sebacic acid (SA) release. Microsphere degradation was pH sensitive, being enhanced at high pH, and became more stable in acidic conditions, irrespective of the incorporation of gelatin in the matrix. For the gelatin-free microspheres, a close correlation of SA release and AO release was observed (2% loading), suggesting a release mechanism that was controlled dominantly by degradation. However, the incorporation of gelatin into the microsphere significantly extended the periods of molecule release from P(FAD-SA) microspheres, although the degradation profile of the microspheres themselves was quite similar to that of gelatin-free microspheres. It is possible that an interaction between FAD monomers and gelatin molecules causes continued release, even after the polymer matrix completely degrades (even after complete degradation, FAD monomers remain because of their poor water solubility). Thermal analysis of polyanhydride microspheres at different degradation stages demonstrated that a crystalline structure was formed between gelatin and the FAD monomers produced with microsphere degradation. This gelatin effect on the extended period of drug release was not observed for microspheres prepared from other polyanhydrides: poly (sebacic acid) and its co-polymer of bis(p-carboxyphenoxy) propane and sebacic acid. It is therefore likely that the crystalline structure formed between gelatin and FAD monomers may function as a reservoir for water-soluble drugs, leading to an extended period of molecule release from the gelatin-loaded P(FAD-SA) microspheres.     

Push-Pull Controlled Drug Release Systems: Effect of Molecular Weight of Polyethylene Oxide on Drug Release

First, an elementary osmotic pump (EOP) with a simple structure was prepared using polyethylene oxide (PEO) and NaCl as an excipient, and the influence of the molecular weight (Mw) of PEO on drug release was investigated. In the dissolution test of EOP, it was observed that the gelated core tablet was pushed out through the orifice. The dissolution profile of EOP was sigmoidal, and despite the short time, a zero-order release region was observed. The gel swelling rate in the zero-order region was independent of the Mw of PEO. It was also found that higher the Mw of PEO, the larger the saturated swelling amount. Next, a push-pull pump (PPP) with almost identical formulation to that of EOP was prepared, and its drug release characteristics were investigated. PPPs were prepared by varying the combination of Mws of PEO in both layers, and their dissolution profiles were compared. It was found that PPP using a low-Mw PEO for the drug layer and PEO with a high-Mw in the push layer showed the longest dissolution profile of the linear region. The obtained findings suggested that the properties of PEO and its hydrogel play a crucial role in the drug release of PPP.     

口服脉冲控释给药系统的释药机制及其应用

口服脉冲控释给药系统因具有定时或定位释放的特点而成为当前药剂研究领域的热点.本文介绍了其释药机制,包括有机酸诱导、渗透压调节、pH依赖、时间依赖、酶依赖、pH-时间依赖及各释药机制应用实例.提出了该给药系统在应用中,尤其是对中药复方制剂所存在的一些问题,期望为口服中药脉冲控释给药系统的研究提供思路.     

Polymer Microneedles for Controlled-Release Drug Delivery

Purpose As an alternative to hypodermic injection or implantation of controlled-release systems, this study designed and evaluated biodegradable polymer microneedles that encapsulate drug for controlled release in skin and are suitable for self-administration by patients. Methods Arrays of microneedles were fabricated out of poly-lactide-co-glycolide using a mold-based technique to encapsulate model drugs—calcein and bovine serum albumin (BSA)—either as a single encapsulation within the needle matrix or as a double encapsulation, by first encapsulating the drug within carboxymethylcellulose or poly-l-lactide microparticles and then encapsulating drug-loaded microparticles within needles. Results By measuring failure force over a range of conditions, poly-lactide-co-glycolide microneedles were shown to exhibit sufficient mechanical strength to insert into human skin. Microneedles were also shown to encapsulate drug at mass fractions up to 10% and to release encapsulated compounds within human cadaver skin. In vitro release of calcein and BSA from three different encapsulation formulations was measured over time and was shown to be controlled by the encapsulation method to achieve release kinetics ranging from hours to months. Release was modeled using the Higuchi equation with good agreement (r² ≥ 0.90). After microneedle fabrication at elevated temperature, up to 90% of encapsulated BSA remained in its native state, as determined by measuring effects on primary, secondary, and tertiary protein structure. Conclusions Biodegradable polymer microneedles can encapsulate drug to provide controlled-release delivery in skin for hours to months.     

Controlled Drug Release of Highly Water-Soluble Pentoxifylline from Time-Limit Disintegration-Type Wax Matrix Tablets

A pulsatile drug release system with a dry-coated tablet containing pentoxifylline was investigated for controlling drug release in the gastrointestinal tract. The system consisted of a core tablet with disintegrator and outer layer, which obtained compression from the ground mixtures of pentoxifylline and behenic acid. Drug release from a dry-coated tablet was investigated at 37°C in JPXII 2nd fluid at pH 6.8. The drug release from the outer layer was fitted to the Cobby model. The drug release from the wax matrix increased significantly after tablet disintegration; therefore, the drug release profiles showed typical sigmoidal curves. The disintegration time depended on the weight fraction of the core tablet, and the drug release rate after disintegration increased with increasing drug concentration in the core tablet. The relationship between the time required for 50% drug release and the disintegration time was linear, indicating that the drug release rate was controlled by regulating the disintegration time.     

脂质乳剂释药机制及其靶向性的研究进展

简要介绍了脂质乳剂释药机制、体内外试验方法及影响释药特性和靶向性的因素，如粒径、药物性质、表面修饰等研究进展。     

缓控释注射给药系统载体--温度敏感型聚合物概述

综述了作为缓、控释注射给药系统载体的温度敏感型聚合物的概况,介绍了几种聚合物的胶凝机理和特点.