Biodegradable Nanoparticles-Loaded PLGA Microcapsule for the Enhanced Encapsulation Efficiency and Controlled Release of Hydrophilic Drug

Recently, nano- and micro-particulate systems have been widely utilized to deliver pharmaceutical compounds to achieve enhanced therapeutic effects and reduced side effects. Poly (DL-lactide-co-glycolide) (PLGA), as one of the biodegradable polyesters, has been widely used to fabricate particulate systems because of advantages including controlled and sustained release, biodegradability, and biocompatibility. However, PLGA is known for low encapsulation efficiency (%) and insufficient controlled release of water-soluble drugs. It would result in fluctuation in the plasma levels and unexpected side effects of drugs. Therefore, the purpose of this work was to develop microcapsules loaded with alginate-coated chitosan that can increase the encapsulation efficiency of the hydrophilic drug while exhibiting a controlled and sustained release profile with reduced initial burst release. The encapsulation of nanoparticles in PLGA microcapsules was done by the emulsion solvent evaporation method. The encapsulation of nanoparticles in PLGA microcapsules was confirmed by scanning electron microscopy and confocal microscopy. The release profile of hydrophilic drugs can further be altered by the chitosan coating. The chitosan coating onto alginate exhibited a less initial burst release and sustained release of the hydrophilic drug. In addition, the encapsulation of alginate nanoparticles and alginate nanoparticles coated with chitosan in PLGA microcapsules was shown to enhance the encapsulation efficiency of a hydrophilic drug. Based on the results, this delivery system could be a promising platform for the high encapsulation efficiency and sustained release with reduced initial burst release of the hydrophilic drug.     

Pioglitazone-Loaded PLGA Nanoparticles: Towards the Most Reliable Synthesis Method

Recent findings have proved the benefits of Pioglitazone (PGZ) against atherosclerosis and type 2 diabetes. Since the systematic and controllable release of this drug is of significant importance, encapsulation of this drug in nanoparticles (NPs) can minimize uncontrolled issues. In this context, drug delivery approaches based on several poly(lactic-co-glycolic acid) (PLGA) nanoparticles have been rising in popularity due to their promising capabilities. However, a fully reliable and reproducible synthetic methodology is still lacking. In this work, we present a rational optimization of the most critical formulation parameters for the production of PGZ-loaded PLGA NPs by the single emulsification-solvent evaporation or nanoprecipitation methods. We examined the influence of several variables (e.g., component concentrations, phases ratio, injection flux rate) on the synthesis of the PGZ-NPs. In addition, a comparison of these synthetic methodologies in terms of nanoparticle size, polydispersity index (PDI), zeta potential (ζ_p), drug loading (DL%), entrapment efficiency (EE%), and stability is offered. According to the higher entrapment efficiency content, enhanced storage time and suitable particle size, the nanoprecipitation approach appears to be the simplest, most rapid and most reliable synthetic pathway for these drug nanocarriers, and we demonstrated a very slow drug release in PBS for the best formulation obtained by this synthesis.     

缓释型固体油井防垢剂的研制及应用

针对吐哈鄯善油田油井的结垢状况,优选出性能优良的基础防垢剂HG-1,然后添加适量的增效剂、填充剂、表面活性剂、粘合剂,采用高温熔融法制备了适用于鄯善油田油井的固体防垢剂SQJ-1。固体防垢剂SQJ-1有效释放时间长达192 d,有效成分含量≥56%,当其用量达到40 mg.L-1时,防垢率≥97%。现场防垢实验结果表明,固体防垢剂SQJ-1可有效防垢增油、延长检泵周期,是一种有效时间长、效果好、安全可靠的防垢剂。     

PLGA Biodegradable Nanoparticles Containing Perphenazine or Chlorpromazine Hydrochloride: Effect of Formulation and Release

In our study, poly(dl-lactide-co-glycolide) (PLGA) nanoparticles loaded with perphenazine (PPH) and chlorpromazine hydrochloride (CPZ-HCl) were formulated by emulsion solvent evaporation technique. The effect of various processing variables, including PLGA concentration, theoretical drug loading, poly(vinyl alcohol) (PVA) concentration and the power of sonication were assessed systematically to obtain higher encapsulation efficiency and to minimize the nanoparticles size. By the optimization formulation process, the nanoparticles were obtained in submicron size from 325.5 ± 32.4 to 374.3 ± 10.1 nm for nanoparticles loaded with PPH and CPZ-HCl, respectively. Nanoparticles observed by scanning electron microscopy (SEM) presented smooth surface and spherical shape. The encapsulation efficiency of nanoparticles loaded with PPH and CPZ-HCl were 83.9% and 71.0%, respectively. The drug loading were 51.1% and 39.4% for PPH and CPZ-HCl, respectively. Lyophilized nanoparticles with different PLGA concentration 0.8%, 1.3% and 1.6% (w/v) in formulation process were evaluated for in vitro release in phosphate buffered saline (pH = 7.4) by using dialysis bags. The release profile for both drugs have shown that the rate of PPH and CPZ-HCl release were dependent on a size and amount of drugs in the nanoparticles.     

药物控释体系的研究与控释技术进展

介绍了药物控释体系的种类、作用机理及控释技术最近进展 ,指出发展控释技术意义重大     

单分散性PLGA磁性微球的制备及其缓释性

为获得单分散性PLGA磁性微球,以纳米四氧化三铁明胶分散液作为内水相(W1),PLGA(聚乳酸羟基乙酸共聚物)的二氯甲烷溶液作为油相(O),PVA(聚乙烯醇)水溶液作为外水相(W2),利用T型微通道并采用复合乳液法制备PLGA磁性微球,考察油相(O)质量浓度、外水相(W2)质量分数、流速比及油相与内水相体积比对微球制备的影响。借助FTIR、SEM、光学显微镜及VSM(振动样品磁强计)对磁性微球组分、形貌、粒径分布和磁学性能进行表征;并以阿司匹林作为药物模型进行缓释性测试。结果表明:油相中PLGA质量浓度为0.050kg/L,外水相(W2)中PVA质量分数为1%及2%,流速比v(W2)∶v(W1/O)=120∶1且体积比V(O)∶V(W1)=2∶1时可均匀成球,其粒径分布系数CV值仅为4.66%,表现出良好的单分散性;此时,比饱和磁化强度可达1.52emu/g,兼具优异顺磁性。制得的载药微球在60 h内表现出阶段性匀速释放,且有较好的磁响应性,有望用于磁响应性药物载体。     

药物与聚乳酸包埋物缓释性能的研究

采用包埋法制备了聚乳酸与药物的混合物,测定了聚乳酸相对分子质量大小、聚乳酸与药物的配比、聚乳酸与不同药物形成的包埋物及光照对药物释放量的影响,研究了包埋物在不同环境下的释放能力。     

槲皮素微胶囊的稳定性及缓释性能研究

以大豆蛋白、乙基纤维素、单甘酯作为复合壁材,将槲皮素制成微胶囊产品,探讨了槲皮素微胶囊的稳定性及在不同极性溶剂中的释放性能。结果表明,槲皮素微胶囊化后可以明显提高槲皮素的光稳定性和热稳定性,减弱了pH的影响和氧气对槲皮素的氧化降解。在极性不同的介质中微胶囊槲皮素均具有缓释作用,在极性溶剂水中其缓释能力最强,5％的微胶囊水溶液（W／V）,槲皮素的溶出平衡时间为15h。     

交联魔芋葡甘聚糖水凝胶包裹尿素的缓释效果

以魔芋粉为原料，经三级醇溶去杂工艺，得纯化魔芋葡甘聚糖；以环氧氯丙烷为交联剂，制备出交联魔芋葡甘聚糖水凝胶；交联魔芋葡甘聚糖水凝胶于尿素水溶液中强力搅拌，抽滤，制得包裹尿素的交联魔芋葡甘聚糖水凝胶。试验了交联魔芋葡甘聚糖水凝胶对尿素的包裹率；以及包裹尿素的交联魔芋葡甘聚糖水凝胶缓释尿素的效果。结果表明，交联魔芋葡甘聚糖水凝胶对尿素缓释效果良好。     

缓释/控释肥料用包膜材料的现状及发展探讨

缓释／控释包膜肥料具有提高肥料利用率、降低环境污染、提高作物产量等特点,因而成为目前肥料研究与开发的热点之一,包膜材料则是影响肥料释放速率的关键。本文简要介绍缓释／控释包膜肥料的研究现状、讨论了若干目前已被采用包膜材料的特点、并对包膜材料的发展前景进行了初步探讨。     

缓/控释肥料的新进展及特性评价

缓／控释肥料具有提高肥料利用率、降低环境污染、提高作物产量等特点,因而成为目前肥料研究与开发的热点。本文综述了各种类型缓／控释肥料的最新研究进展,介绍了几种检测缓／控释肥养分释放特性的方法。此外,文章分析了缓／控释肥料推广应用中存在的问题,并对其未来发展进行了展望。     

缓/控释肥料的研究与发展

介绍了缓释、控释肥料的概念以及区分二者的意义;概述了缓/控释肥包膜材料、技术、工艺的研究应用状况;分析了包膜材料与包膜缓/控释肥料的发展方向.     

聚丙烯酸水凝胶的制备及其对结晶紫的控制释放

通过自由基聚合制备出聚丙烯酸水凝胶,考察了交联剂、单体中和度、盐对水凝胶溶胀性能的影响,以结晶紫为模板研究了水凝胶对结晶紫的控制释放性能。结果表明,交联剂用量在0.8%,单体中和度为70%时水凝胶溶胀性能最佳;在相同条件下,聚丙烯酸水凝胶的溶胀率随盐溶液浓度的增大而降低;聚丙烯酸水凝胶对药物具有良好的控制释放性能,对结晶紫的释放为扩散机制。     

纤维素及其复合凝胶对除草剂的控制释放作用

经Al3+交联得到的羧甲基纤维素(CMC)凝胶用于包载除草剂2,4-滴,以控制其释放速度,延长药效,减轻农药污染。在CMC凝胶制剂中加入改性膨润土可以进一步延缓2,4-滴的释放,其50%释放量所需时间(t50)由9.18h延长到16.0h。不同种类的膨润土在复合凝胶制剂中的作用效果与其对2,4-滴的吸附性能密切有关,吸附性能越强,控制除草剂释放的效果越好。释放动力学分析表明,2,4-滴由凝胶制剂中的释放主要受到扩散控制。     

难溶性固体农药微胶囊化及控制释放研究进展

难溶性固体化合物广泛存在于农药、医药等领域,其稳定性受多种环境因素影响,在应用上存在微胶囊化的需要。介绍了难溶性农药微胶囊化适用的制备方法、芯材释放速率的调控方法和影响因素的研究进展。     

改性粘土作为载体在农药控制释放中的应用

粘土可与多种阳离子发生离子交换,制备具有不同吸附性能的改性粘土。后者作为农药控制释放载体,可适用于各类性质和用途不同的农药,从而提高农药利用率,控制农药污染。通常,改性粘土对农药的吸附作用越强,农药释放越慢。将改性粘土与天然水溶性高分子一起制备复合农药载体,有利于提高载药能力,进一步拓展应用范围,强化对农药释放过程的调控作用。     

两亲性三嵌段共聚物的合成、表征及其药控释放行为的研究

以三硫代碳酸双(α,α′-二甲基α-″-乙酸)酯为链转移剂,以苯乙烯(St)或甲基丙烯酸甲酯(MMA)为亲油性单体,以甲基丙烯酸二甲氨基乙酯(DMA)为亲水性单体,AIBN为引发剂,通过可逆加成断裂链转移(RAFT)聚合得到两种两亲性三嵌段共聚物,通过凝胶渗透色谱(GPC)测试其组成分别为PS16-PDMA56-PS16,PMMA11-PDMA38-PMMA11,PMMA15-PDMA40-PMMA15,Mw/Mn分别为1.20、1.27、1.29。并用1HNMR进一步表征了嵌段共聚物结构。TEM及粒度测试研究发现,PS-PDMA-PS在特定溶剂中可以自组装成球形胶束,其尺寸在380 nm左右;而PMMA-PDMA-PMMA自组装成的胶束则呈均匀的球形,胶束分散较好,粒径约在120 nm左右。并研究了3种胶束对水溶性模型药物对羟基苯甲醚(HOA)的缓释效果,发现在同一时间PS-PDMA-PS胶束的累积释放量比其他胶束的小,药物的控释遵循扩散机理,并且胶束尺寸对药物的释放速率影响较大。     

环保型控制释放多功能水处理剂的制备及性能

该文以自然界广泛存在且对环境无害的硅、硼为控制释放型水处理试剂的主要成分,并通过在玻璃中添加氧化银的方式引入抗菌活性物质,利用硅、硼自身具有的缓蚀、阻垢特性及银离子所具有的抗菌灭藻性能,制备得到控制释放型多功能水处理剂.得到了制备该产品的组成配方及工艺条件;利用X射线衍射测试及红外光谱测试评价了产品的基本性能;研究了环...     

再生丝素蛋白/海藻酸盐包药微胶囊的结构与释药性能

以模型药物消炎痛(吲哚美辛)作囊芯,再生丝素蛋白和海藻酸盐(FB/AG)作囊膜,在液体石蜡,Span-80的W/O型乳化体系中于50～60℃,高速搅拌下,采用复凝聚法制备包药微胶囊。采用扫描电镜(SEM)、激光粒度仪、X ray、FTIR、DSC等测定并表征了包药微胶囊的结构。结果显示,微胶囊呈近似球型,粒径为65μm左右,粒径呈正态分布,再生丝素蛋白与海藻酸盐之间具有相互作用,结晶程度提高。采用药物体外释放法测其释药性能,该包药微胶囊24h的释药率为24%,海藻酸盐微胶囊为42%,药粉为80%,FB/AG具有缓释效果。     

吡虫啉/羧甲基壳聚糖凝胶球的制备及释放性能

以羧甲基壳聚糖为载体材料,吡虫啉为模型药物,采用双组分交联剂的悬浮交联法制备了吡虫啉/羧甲基壳聚糖凝胶球,采用扫描电镜和红外光谱对凝胶球进行了表征,探讨了制备工艺条件对凝胶球性能影响,利用体外释放实验测定了交联羧甲基壳聚糖凝胶球的释放特性。研究表明,采用氯化钙-戊二醛双组分交联剂可获得外形规整而表面带有皱褶的载药凝胶球;交联凝胶球中吡虫啉与羧甲基壳聚糖间无化学键合;交联凝胶球的载药量和包封率随交联时间和氯化钙浓度的增加呈先升后降趋势,随戊二醛体积分数的增加呈显著下降趋势;吡虫啉释放速度,随交联剂中氯化钙浓度和戊二醛体积分数的增加呈先降后增趋势;随交联时间变化不显著。在较佳条件下可制备载药量为25.71%的吡虫啉/羧甲基壳聚糖凝胶球,控释时间可达6 d;释放机理初步确定为Super CaseⅡ型传递机理。