Innovative and high performance synthesis of microcapsules containing methyl anthranilate by microsuspension iodine transfer polymerization

In this research, preparations of polymer microcapsule encapsulated methyl anthranilate (MA) as an essential oil model by both microsuspension conventional radical polymerization (ms CRP) and microsuspension iodine transfer polymerization (ms ITP) using methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA) copolymer as the polymer shell were studied. In the case of ms CRP, a large amount of free polymer particles nucleated in aqueous medium were obtained. Using ms ITP, the free polymer particle formation was significantly depressed. Iodoform (CHI₃) as a chain transfer agent with 0.8 wt% relative to the monomer, such a phenomenon was not observed. Various emulsifiers (oleic acid, Span 80 and PEG 30 dipolyhydroxystearate (DPHS)) with low hydrophile–lipophile balance value were used to retain MA in the monomer droplets or polymerizing particles. DPHS is the most effective emulsifier to retain MA in microcapsules giving 58% encapsulation at 20 wt% of DPHS relative to MA. In addition, from the controlled release study, only 55 wt% of the encapsulated MA was released by 90 days. Polymer microcapsule encapsulated MA using an MMA‐EGDMA copolymer shell with a high percentage of encapsulation and without free polymer particles was successfully prepared for the first time. Based on slow release of the encapsulated MA, the prepared microcapsules could be used in various applications. © 2017 Society of Chemical Industry     

Preparation and characterization of controlled-release microencapsulated acids for deep acidizing of carbonate reservoirs

Based on the deficiency of traditional acidification or acid pressure technology in the development of carbonate oil and gas resources, a microcapsule which wraps hydrochloric acid and can be released through temperature control was prepared by using microcapsule technology. The microcapsules were prepared with polyurethane prepolymer (PUA) and 1,6-hexadiol diacrylate (HDDA) polymer as wall material and hydrochloric acid as core material by two emulsification and photocatalysis methods. Its parcel rate is 61.9%. Fourier transform infrared spectroscopy characterization confirmed the successful photopolymerization of PUA prepolymer and HDDA in a strong acid environment. The microscopic morphology analysis of electron microscope showed that the microcapsule was regular and uniform spherical with smooth and dense surface. The particle size analysis showed that the microcapsules were mainly distributed between 40 and 300 μm, and the average particle size was 114.02 μm.The glass temperature of microcapsule wall material was 97°C by DSC method. The release rate of microcapsules was accelerated with the increase of release temperature. The cumulative release rate of acid solution of microcapsules for 3 h reached 28.4%, and the final release rate of microcapsules for 12 h reached 90.7% under 100°C. In addition, the release of microcapsules is less affected by the formation salinity. At 90°C, the maximum release rate of 7.5 g/L CaCL₂ was 49.1%, lower than that of 59.4% in pure water, showing the good salt resistance of the wall materials of microcapsules.     

界面聚合法制备农药微胶囊剂的研究

选取杀螟硫磷作为有效成分,介绍了界面聚合法制备农药微胶囊剂的改进方法,将多异氰酸酯预处理后再进行聚合反应,并与农药微胶囊剂的传统制备方法进行了对比,发现方法改进后,微胶囊的囊皮特性得到很好改善,微胶囊的包药率提高约一倍,达到95％以上,热贮稳定性有很大程度提高,分解率从15％降低到2％左右,释放速度更加缓慢,而且可以通过不同的条件控制释放速度,说明改进后方法制得的微胶囊剂能更好地提高农药的持效性,可以减少施药量一文中还着重研究了多种反应条件对农药微胶囊化的影响,测定了农药微胶囊在水中的释放速度,实验表明：释放速度可以通过界面聚合反应的时间、微胶囊剂粒子的大小、农药与囊材的不同用量比、两种水相单体的不同用量比等因素进行控制和调节,以获得适合实际要求的微胶囊：     

Microencapsulation of sulphur in polyurea

Abstract

Polyurea microcapsules containing 33, 50 and 67 wt-% sulphur were prepared by interfacial polymerisation. The characteristics of the fabricated microcapsules were investigated for morphology, thermal property and release property in vulcanising rubber. The morphology showed that microcapsules loading 33 wt-% sulphur were spherical and smooth. The microcapsule sizes decreased going from 33 to 50 to 67 wt-% sulphur. Thermal analysis demonstrated that the microcapsules were thermally stable below 250°C. The process of sulphur released from polyurea microcapsules was put forward in vulcanising nitrile butadiene rubber (NBR) and verified by vulcanising property and tensile strength and elongation of the vulcanised NBR.     

纳米SiO2改性石蜡相变微胶囊涂料的制备及性能表征

相变微胶囊在能源节约方面可以起到重要作用.以石蜡为芯材,三聚氰胺树脂为壳材,并使用纳米SiO2作为改性剂,采用原位聚合法制备相变微胶囊.研究了纳米SiO2用量对微胶囊性能的影响.通过差示扫描量热仪(DSC)、扫描电子显微镜(SEM)以及同步热分析仪(TGA)等对相变微胶囊的相变特性、表面形貌、热稳定性以及包裹率等进行了...     

5％阿维菌素·噻唑膦复配型微胶囊悬浮剂制备及性能

[目的]为了降低阿维菌素和噻唑膦的分解以及对作物的药害,提高其药效,制备阿维菌素·噻唑膦复配型微胶囊悬浮剂。[方法]以甲苯二异氰酸酯(TDI)和乙二胺为反应单体,阿维菌素和噻唑膦为芯材,二甲苯为溶剂,采用界面聚合法制备微胶囊。[结果]该微胶囊的平均粒径为6.095μm,近似圆球形,表明光滑,阿维菌素和噻唑膦的包封率分别达到99.51%和80.86%,载药量分别为1.03%和4.02%,悬浮率分别为85.43%和97.74%。该微胶囊悬浮剂的缓释性能优于85%噻唑膦原药、20%噻唑膦水乳剂、1.8%阿维菌素乳油和3%阿维菌素水乳剂;该微胶囊悬浮剂具有优异的屏蔽紫外光降解性能。[结论]阿维菌素和噻唑膦通过界面聚合法微胶囊化后可以显著增强其缓释和屏蔽紫外光降解性能。     

Preparation and properties of poly(propylene carbonate maleate) microcapsules for controlled release of pazufloxacin mesilate

A novel biodegradable aliphatic polycarbonate, poly(propylene carbonate maleate) (PPCMA) was synthesized by terpolymerization of carbon dioxide, propylene oxide, and maleic anhydride (MA), using a polymer supported bimetallic complex as catalyst. The utility of PPCMA to encapsulate and control the release of drug pazufloxacin mesilate (PZFX), via microcapsules, was investigated. PPCMA microcapsules containing PZFX were elaborated by solvent evaporation method based on the formation of double W/O/W emulsion. The manufacturing parameters such as the volume ratio of V(PPCMA) : V(PZFX), the concentration of stabilizer gelatin in outer aqueous phase played major roles on microcapsule characters, and were altered to optimize the process parameters. The PPCMA‐PZFX microcapsules were obtained with smooth and spherical surface under optimum condition, the mean diameter of microcapsules was ～ 2 μm, and the drug loading and drug encapsulation efficiency of the microcapsules were 22.9 ± 1.05% and 82.1 ± 2.03%, respectively. PZFX released from PPCMA microcapsules was found to reach 89.8 ± 2.89% after 36d in a pH 7.4 phosphate‐buffered solution, and the release profile obeyed the Higuchi equation. The results suggest that the new polymer PPCMA provides an alternative to degradable matrix polymers for long‐term sustained releasing drug delivery systems. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Control of release characteristics in pH‐sensitive poly(vinyl alcohol)/poly(acrylic acid) microcapsules containing chemically treated alumina core

The pH‐sensitive poly(vinyl alcohol)/poly(acrylic acid) hydrogel microcapsules containing vitamin B₁₂‐loaded Al₂O₃ core were prepared with a three‐step emulsion polymerization. Al₂O₃ was chemically treated with HCl or NaOH solutions at room temperature for 24 h to modify the binding properties with vitamin B₁₂. The colon‐targeted release characteristics of vitamin B₁₂ from the microcapsules were evaluated at different pHs. These microcapsules showed the faster and larger release of vitamin B₁₂ due to the high swelling of microcapsule shell as the pH was changed into more basic condition. However, these microcapsules showed the slower and less release of vitamin B₁₂ as the acid value of Al₂O₃ increased due to the strong binding interaction between Al₂O₃ core and vitamin B₁₂ even though the initial loading of vitamin B₁₂ was higher. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

辣椒碱微胶囊的释放动力学研究

测定合成辣椒碱微胶囊在盐水、碱性及酸性三种释放环境下的释放曲线.在三种释放环境下,合成辣椒碱的释放率(ARP)具有显著的差异,盐水环境下的释放率最小.通过零级动力学方程、一级动力学方程、Higuchi模型方程对所得数据进行拟合,结果表明,三种释放环境中合成辣椒碱的释放动力学均适用于一级动力学方程.     

Preparation of polyethersulfone–alginate microcapsules for controlled release

In this study, polyethersulfone (PES)–alginate microcapsules were prepared for drug‐controlled release, and vitamin B₁₂ (VB₁₂), rifampicin (RFP), and bovine serum albumin (BSA) were used as model drugs. Different microcapsules were prepared by the variation of the crosslinking degree of alginate and the variation of the chemical components of the microcapsule membrane, including the PES and polyethylene glycol (PEG) contents. Systematic experiments were carried out to study their influences on the release profile of the model drugs. The results showed that with the increase of the crosslinking degree of the alginate, the drug release rate increased; whereas with the increase of the PES concentration used to prepare the microcapsule membrane, the drug release rate decreased. The contents of the PEG in the microcapsule membrane also affected the drug release. This study enriched the methodology of the fabrication of the microcapsules, and the microcapsules may have a potential use for controlled release. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

阿司匹林微胶囊的制备及其体外释放行为的研究

近年来,微胶囊技术在生物医药、化工、食品等行业得到了广泛应用和发展.以液中干燥法制备阿司匹林微胶囊,研究了微胶囊的形成过程、表观形貌、粒度及其体外释放行为.研究结果表明,阿司匹林微胶囊形成过程中,乙基纤维素分散成球,继而在各微球表面析出,微球越来越细密,表面空洞减小,最终形成完整的微胶囊.微胶囊表面致密、光滑,有少量细小的孔洞,多数呈球形,但粒度不均匀,有不规则杂片存在.粒度基本呈正态分布,平均粒径为1 445 nm.随着制备微胶囊过程中阿司匹林原料药加入量的增加,微胶囊成品的实际载药量增加,但其包覆率却随之减小.在体外释放初始阶段,微胶囊中阿司匹林的释放较快,继而释放速率减慢呈缓慢上升趋势.加入少量药品制备的微胶囊中阿司匹林释放速度较大.     

维生素E微胶囊的制备及其干燥后释放性研究

本文采用微胶囊造粒仪制备出不同尺寸及不同含量的维生素E微胶囊(BUCHI,B-395)。并通过实验研究了微胶囊的尺寸和维生素E含量对干燥后产品的维生素E释放性的影响。发现利用微胶囊造粒仪制备微胶囊时,微胶囊的尺寸约为喷嘴直径的两倍。得出微胶囊尺寸越小,干燥产品的维生素E释放速率越快,释放比越高。干燥产品维生素E的含量越高时,释放量达到饱和的时间越短,释放性越好。     

Control and enhancement of permselectivity of membrane‐based microcapsules for favorable biomolecular transport and immunoisolation

The success of membrane‐based, cell‐encapsulating microcapsules depends on the membrane permselectivity that provides efficient inward transport of nutrients, therapeutic protein egress, and complete exclusion of immunoglobulins. Microcapsules with a calcium crosslinked alginate core and a genipin‐crosslinked chitosan alginate (GCA) were prepared with good control over size, membrane thickness and density. Importantly, in this study, we report a novel approach of using three relevant biomolecules and investigating the effects of the membrane characteristics (thickness and density) and microcapsule size on biomolecular mass transport across the GCA microcapsules using mathematical models based on a balance of the chemical potential. Scaling analysis was used to interrelate the membrane thickness, chitosan–alginate reaction rate constant, and diffusion coefficient. The resistance to diffusion of the three biomolecules increased with membrane density and thickness. Interestingly, swelling in the large microcapsules resulted in an increase in permeability, allowing larger biomolecules (immunoglobulin and carbonic anhydrase) to diffuse more readily. In the case of the smaller biomolecule, vitamin B₁₂, a shorter diffusion path length in smaller microcapsules allowed better ingress. When compared with other microcapsules, the GCA microcapsules possess improved permselectivity for them to allow diffusion of small nutrient molecules and proteins, whereas completely excluding antibodies. Also, these results elucidate the importance of membrane properties and microcapsule size to realize favorable transport of biomolecules. © 2011 American Institute of Chemical Engineers AIChE J, 2011     

高压静电法制备载阿糖胞苷海藻酸钙-几丁聚糖微胶囊

采用海藻硅酸钠和几丁聚糖为原料制备海藻酸钙-几丁聚糖药物缓释微胶囊,初步考察了载阿糖胞苷微胶囊的制备以及不同分子量几丁聚糖、静/动态载药方式对阿糖胞苷释放性能的影响。     

季铵化壳聚糖包覆腐殖酸微胶囊的制备与性能研究

以季铵化壳聚糖（QCTS）为壁材、腐殖酸(HA)为芯材,制备季铵化壳聚糖包覆腐殖酸(QCTS/HA)微胶囊。采用傅里叶红外光谱(FTIR)、偏光显微镜(POM)、扫描电子显微镜(SEM)对微胶囊的性能进行表征。以芯壁比〔m(HA):m(QCTS)〕、固化剂用量和搅拌速度作为单因素,探讨了微胶囊的最佳制备条件。并且对最佳制备条件下的微胶囊进行了形貌观测以及吸水和保水性能测试。结果表明,QCTS/HA微胶囊的最佳工艺参数为：m(HA):m(QCTS)=3:1,固化剂用量为总质量的1%,搅拌速度为500r/min;与相同条件下未改性的微胶囊CTS/HA相比,改性后的QCTS/HA微胶囊包覆层表面孔隙结构比较完善,分布均匀,孔洞较多,具有更加优异的吸水和保水性能,其12h的吸水率和保水率分别高达348%和208%。 关键词：季铵化壳聚糖;腐殖酸;核壳结构;微胶囊;吸水性能,保水性能     

响应面法优化微胶囊复合壁材配比

采用高压静电微胶囊制备装置,以成囊合格率为检测指标,选择海藻酸钠等为壁材,运用Box-Behnken中心组合设计和响应面分析,研究了壁材配比对微胶囊特性的影响。得到的最优条件是:壁材组成为质量分数1.53%(以下都是质量分数)海藻酸钠,4.52%聚乙烯醇,1%明胶,1%甘油,成囊溶液氯化钙质量浓度为22.86g/L,微胶囊合格率为87.37%。在最优条件下制备出的微胶囊内外表面光滑,囊壁透明,分散性好,形态完整。可为食品、医药、化工等微胶囊化壁材配比选择提供参考。     

溶剂蒸发法制备高效氯氟氰菊酯微胶囊及其性能表征

针对高效氯氟氰菊酯使用过程中对人体皮肤的刺激性以及对水生生物的高毒性,以乙基纤维素为壁材,二氯甲烷为溶剂,通过设计L9（34）正交试验,采用溶剂蒸发法制备高效氯氟氰菊酯微胶囊,同时对微胶囊的理化性质和缓释特性进行表征。根据微胶囊平均粒径和未包封率的综合评分确定最佳制备工艺为：25%二氯甲烷,0.75%乙基纤维素,2%乳化剂,剪切8 min。扫描电子显微镜观察发现,所制微胶囊具有粒径大小均匀,表面光滑等特性;红外光谱图表明,高效氯氟氰菊酯被乙基纤维素包埋;释放特性曲线也表明微胶囊具有较好的缓释性能。该工艺操作简单,制备周期短,成囊性好,可为农药微胶囊的制备提供有效途径。     

Preparation of poly(vinyl alcohol)/poly(acrylic acid) microcapsules and microspheres and their pH-responsive release behavior

The pH-responsive poly(vinyl alcohol)/poly(acrylic acid) hydrogel microparticles containing vitamin B₁₂ were prepared with emulsion polymerization. Both microcapsule and microsphere were easily produced by simply changing the sequence of ingredient addition during the emulsion polymerization. The microparticles showed the faster and larger release of vitamin B₁₂ due to the higher swelling of hydrogel by electrostatic repulsion of carboxylate groups in poly(acrylic acid) as the pH was changed into more basic condition. The microcapsules showed a faster release than the microspheres did due to the less hindered passage through the thinner shell of microcapsules. The poly(vinyl alcohol)/poly(acrylic acid) hydrogel microparticles either protected or released the vitamin B₁₂ effectively depending on pH.     

干扰素壳聚糖/海藻酸钠微囊控释制剂载体的初步研究

目的研究蛋白质类药物口服控释给药的可行性。方法壳聚糖与海藻酸钠通过聚电解质络合反应制备成壳聚糖/海藻酸钠微囊,以干扰素为模型药物,研究不同pH条件下,药物的控制释放情况。结果微囊的粒径为1 mm左右,其干扰素的包封率达90.0%以上,微囊在模拟胃液(pH1.0)中,3h药物释放不到5%;在模拟肠液(pH7.4)中,3h药物释放近100%。结论壳聚糖/海藻酸钠微囊有可能成为蛋白质类药物口服控释制剂的载体。     

毛细管破碎法制备尼莫地平漂浮缓释微囊

为增加尼莫地平在体内的停留时间,以海藻酸魔芋葡甘聚糖壳聚糖微囊为缓释载体,利用毛细管破碎法,制备了尼莫地平漂浮缓释微囊。在破碎频率50Hz条件下,利用0.3mm和0.43mm内径的针头,分别制备了粒径1.055mm±10.6%与1.295mm±9.3%的漂浮微囊,扫描电镜照片表明漂浮微囊球形度好,内部中空。药物释放实验表明,普通尼莫地平缓释片剂在1h内完全释放,而尼莫地平漂浮微囊持续释放可达12h,粒径1.055mm微囊由于覆壳聚糖比例相对较高,药物释放速率相对较低。