磁性壳聚糖-聚丙烯酸载药微球的释放性能研究

对合成的壳聚糖-聚丙烯酸及磁性壳聚糖-聚丙烯酸微球用扫描电镜进行形貌观察,并测定了磁性壳聚糖-聚丙烯酸微球的热稳定性.以牛血清白蛋白(BSA)为模拟蛋白药物,研究了载有BSA的磁性壳聚糖-聚丙烯酸微球的释放性能.结果表明,壳聚糖-聚丙烯酸共聚物外形呈片层状;而磁性壳聚糖-聚丙烯酸微球为致密微球,粒径约在100～400nm之间,具有较好的分散性,磁性壳聚糖-聚丙烯酸微球在温度区间(0～135℃)内具有良好的热稳定性.载有BSA的磁性微球在模拟肠液中刚开始时有一个突释过程,之后缓慢释放,在6h左右达到了平衡,最终释放率可达到80.5%;而在模拟胃液中几乎没有释放,平衡释放率只有5.8%.     

磁性壳聚糖复合微球的制备和性能研究

本文采用乳化交联法制备了可附载放射性核素的磁靶向药物载体-磁性壳聚糖复合微球.考察了壳聚糖浓度、Fe3O4/壳聚糖质量比及搅拌速度等因素对磁性壳聚糖微球粒径、粒径分布以及形貌等对复合过程的影响,确定了制备高磁响应性的磁性壳聚糖的最佳条件,并借助不同手段对磁性壳聚糖的粒径、粒径分布、形貌及磁性能进行了初步表征.     

磁性壳聚糖微球的制备及其应用研究

磁性壳聚糖微球具有成本低、无毒、无味、耐碱、耐腐蚀、易降解及易回收等特点,广泛应用于多个领域.该文综述了磁性壳聚糖微球的制备方法和工艺特点,阐述了其在固定化酶、蛋白质和外源凝集素的分离与提纯、细胞分离、释药与靶向作用、废水处理等方面的应用进展,对磁性壳聚糖研究发展方向提出了建议.     

载药壳聚糖缓释微球的制备及其释放研究

实验采用乳化交联法,使用复合交联剂(先用甲醛交联,再用戊二醛交联),制得盐酸四环素壳聚糖缓释微球,并考察不同分子量的壳聚糖、原料质量比、交联剂用量、复合交联剂用量、搅拌速度对微球的影响,筛选出最佳条件制备出戢药微球,并研究了该微球在扫描电镜和倒置式研究型显微镜下的形态及其在pH=7.4,温度为37℃时的释放规律.结果表明,采用复合交联剂的乳化交联法所制得的微球球形好,粒径分布为5～50μm之间,载药量为26.9%,包封率为56.3%,并且具有良好的缓释效果.     

壳聚糖-固态分散体载药微球的制备及性能研究

首先采用不同分子量的壳聚糖通过乳化-化学交联法制备了4种不同的壳聚糖载药微球。通过对微球的粒径、溶胀率、载药率、包封率等指标检测以及缓释性能的研究,发现分子量为240kDa的壳聚糖制备的载药微球缓释效果明显,载药率、包封率均较高,综合性能优于其它分子量壳聚糖制备的微球。利用该分子量壳聚糖包埋固态分散体制备了壳聚糖-固态分散体载药微球,改善了药物的溶解性并具有药物缓释作用。因此,壳聚糖-固态分散体载药微球是一种理想的药物缓释体系,可以用于包埋溶解性差,生物半衰期短,对胃肠刺激性强的药物。     

磁性壳聚糖微球和纳米球合成的比较研究

实验合成了磁性壳聚糖微球和磁性纳米球,比较了二者合成工艺的异同,通过透射电子显微镜（TEM）观察纳米球的尺寸和形状、用DTG-60型热失重分析仪测定Fe3O4粒子的纯度和含量,结果发现,二者的球结构类型、颗粒尺寸和磁性不同,四氧化三铁的质量分数和交联状态也不同。     

磁性壳聚糖微球的制备及其吸附行为研究

采用乳化交联法,以戊二醛为交联剂,制得磁性壳聚糖微球(MCTS),研究其对刚果红染料的吸附行为。考察戊二醛用量、反应温度和反应时间对刚果红染料吸附效果的影响。并通过正交试验确定最佳吸附条件及主要影响因素。结果表明:在最佳吸附条件下,刚果红染料的脱色率可达95.68%。磁性壳聚糖微球对刚果红染料的吸附遵循Langmuir等温吸附式。磁性壳聚糖微球可再生使用,再生4次后,脱色率仍高于90%。     

壳聚糖-海藻酸钠载药微球的缓释性能研究

采用滴球法制备了壳聚糖-海藻酸钠载四环素微球,考察了原料浓度配比、四环素投药量、添加戊二醛、滴球体积和壳聚糖分子量对微球的影响,并利用紫外分光光度计测试了载药微球在PBS溶液中1h、5h、1d、2d、5d、10d时的药物释放.结果表明,以8.5×104 Da壳聚糖为原料、壳聚糖与海藻酸钠的浓度比为1.2:1、未添加戊二醛、并用大针管滴定的实验组拥有比较理想的缓释性能和良好的生物相容性.     

磁性载药微球的制备

合成了含有铁粉和抗癌药的明胶微球,这种微球在体外磁场的作用下具有定位作用。微球的粒径在０２～１３ｍｍ之间,粒径大小是由制备条件决定的。微球可用戊二醛进行固化。研究了微球体外药物的释放规律     

双氯灭痛壳聚糖水凝胶微球的制备及其性能研究

在Span80与植物油形成的反相胶束体系中,通过戊二醛交联制备出壳聚糖水凝胶微球(CHM)。采用红外光谱和透射电镜等方法对CHM结构及粒子形态进行了研究。同时对CHM的溶胀度及其对模型药物双氯灭痛的体外释放行为进行了考察。结果表明,CHM具有较好的控制药物释放的作用。交联程度对微球粒径、溶胀度及药物释放性能影响较大。     

聚丙烯酸-聚乳酸接枝共聚物涂膜的制备及性能

采用溶液聚合法合成了生物降解材料聚丙烯酸-聚乳酸接枝共聚物(PAA-g-PLLA),通过红外、核磁和凝胶渗透色谱对其结构进行了表征,测定了涂膜的附着力、黏度和硬度等基本性能。正交实验结果表明最佳的合成工艺条件为:硬软单体的质量比为55∶35,过氧化苯甲酰(BPO)的用量为3%,反应温度为85℃,甲基丙烯酸羟乙酯-聚乳酸大单体(HEMA-PLLA)与软硬单体的质量比为1∶2,单体与溶剂的质量比为2∶2。对比聚丙烯酸涂膜和PAA-g-PLLA涂膜的接触角,以及PLLA降解性能看出,PAA-g-PLLA涂膜具有降低表面能和自抛光的双重特性。     

Oral-based controlled release formulations using poly(acrylic acid) microgels

Aim: To investigate the release of hydrophobic and hydrophilic substances from tablets containing Pemulen and Carbopol as excipients. Method: The dissolution patterns of a hydrophobic (diazepam) and a hydrophilic active substance (midodrine-HCl) from different tablet formulations containing a nonmodified polyacrylic microgel (Carbopol 981 F) or a hydrophobically modified polyacrylic microgel (Pemulen®) have been studied. Possible differences in dissolution in phosphate buffer (pH 6.8) and in 0.1 M HCl between tablets produced using wet granulation and direct compression were also investigated. Results: Tablets produced by wet granulation had a greater effect on the release of active substance from the tablets. No major differences were observed in the release patterns of the hydrophilic substance midodrine-HCl from wet granulated tablets based on Carbopol and Pemulen. However, the release pattern of the more hydrophobic drug substance, diazepam, differed considerably between the two polymers. Wet granulation gave reproducible release patterns. The release patterns from the polymers differed considerably at pH 6.8 but were similar at low pH. Conclusions: The release of the diazepam from the hydrophobic polymer Pemulen was very slow, and the release was close to zero order.     

丙烯酸(钠)-壳聚糖吸水树脂的合成

以丙烯酸和壳聚糖为原料,硝酸铈铵为引发剂,N,N-亚甲基双丙烯酰胺为交联剂,在醋酸溶液中合成了丙烯酸壳聚糖吸水树脂。研究了氯化钠、引发剂硝酸铈铵、丙烯酸与壳聚糖配比及交联剂N,N-亚甲基双丙烯酰胺对产物吸水性能的影响,采用正交实验对工艺条件进行了优化。结果表明:氯化钠0.6g、硝酸铈铵96mg、丙烯酸与壳聚糖比例为14.5∶1.5及N,N-亚甲基双丙烯酰胺48mg时合成树脂吸水率最高。     

粉体辐射接枝丙烯酸的聚偏氟乙烯超滤膜的制备

采用粉体辐射接枝丙烯酸的聚偏氟乙烯(PVDF-g-PAA)为材料,以浸没沉淀相转化法制备PVDF-g-PAA超滤膜,研究了接枝后材料溶解性能的变化、以及溶剂种类、聚合物浓度、添加剂种类及浓度、凝胶浴温度制膜参数对PVDF-g-PAA膜结构及性能的影响.结果表明:辐射接枝丙烯酸后,聚合物的溶度参数增大,同时聚合物的极性也增强.在溶剂影响的考察中,以二甲基甲酰胺(DMF)和N-甲基吡咯烷酮(NMP)为溶剂制备的PVDF-g-PAA膜表面致密,透过通量小,对牛血清蛋白(BSA)截留率高;而以二甲基亚砜(DMSO)为溶剂制备的PVDF-g-PAA膜表面孔径较大,透过通量最大,对BSA截留率迅速下降;聚合物浓度的增加使得PVDF-g-PAA膜结构更加致密,纯水通量降低,截留率增加;随着添加剂PEG400浓度的增加,PVDF-g-PAA膜透过通量增加,膜的皮层多孔性增加,厚度增加,大孔发生的起始点向膜内部迁移;在考察的温度区间内(12～23℃),随着凝胶浴温度的升高,PVDF-g-PAA膜通量变大,截留率降低.     

Controlled release behaviors of chitosan/α, β- glycerophosphate thermo-sensitive hydrogels

Chitosan/α, β-glycerophosphate (CS/α, β-GP) thermo-sensitive hydrogels presented flowable solution state at low temperature and semisolid hydrogel when the ambient temperature increased. In this research, different concentrations of metronidazole encapsulated, CS and α, β-GP, as well as different acid solvents, were chosen to evaluate their influences on the drug release behaviors from CS/α, β-GP hydrogels. It was found that there was a sustaining release during the first 3 h followed by a plateau. SEM images showed that drugs were located both on the surface and in the interior of hydrogels. The optimal preparation conditions of this hydrogel for drug release were as follows: 1.8% (w/v) CS in HAc solvent, 5.6% (w/v) α, β-GP and 5 g/L metronidazole encapsulation. Cytotoxicity evaluation found no toxic effect. In order to control the release rate, 2.5 g/L chitosan microspheres with spherical shape and smooth surface were incorporated, and it was found that the initial release process was alleviated, while drug concentration had no obvious effect on the release rate. It could be concluded that the metronidzole release behaviors could be optimized according to practical applications.     

原位聚合法制备壳聚糖-g-聚丙烯酸/高岭土复合树脂

利用无机粘土矿物与烯类单体的接枝共聚反应制备复合高吸水性树脂,具有改善树脂吸水性能、增强凝胶强度、降低产品成本的优点。以高岭土、壳聚糖和丙烯酸为原料,在水溶液中通过接枝共聚反应合成了壳聚糖接枝共聚丙烯酸/高岭土复合吸水树脂。以丙烯酸量为基准,研究了交联剂、引发剂、壳聚糖、高岭土等与丙烯酸的不同质量比对复合树脂吸水倍率的影响。红外光谱分析结果表明,丙烯酸、壳聚糖和高岭土共同参与了接枝聚合反应。以过硫酸胺为引发剂,N,N-亚甲基双丙烯酰胺为交联剂,丙烯酸中和度为70%,引发剂用量0.3%,交联剂用量为0.05%,壳聚糖与丙烯酸的质量比为0.13,高岭土与丙烯酸质量比为0.13时,高吸水性树脂具有较好的综合吸液性能。     

Preparation and properties of calcium sulfate bone cement incorporated with silk fibroin and Sema3A-loaded chitosan microspheres

To search for new bioactive materials which can be used as the substitute of bone repairing and drug carriers, Sema3A-loaded chitosan microspheres (SLCM) and silk fibroin (SF) were mixed with calcium sulfate cement (CSC). SEM, particle size analysis and swelling rate determination were performed to study properties of the microspheres. The drug loading, encapsulation efficiency and drug release rate were determined by ELISA. Microspheres with different SLCM weight contents (0.5%, 1% and 5%) were prepared to determine which one has the strongest mechanical properties and the appropriate setting time. It was revealed that CSC/SF/0.5SLCM has satisfactory mechanical properties, and its in vitro biocompatibility was assessed by MTS. Chitosan microspheres (5--18 μm) were globular, the surface was smooth, and the swelling rate is (77.02±5.57)%. With this formula, the setting time was increased with the addition of SLCM in CSC/SF, and the cumulative drug release rate is 44.62% in 28 d. XRD results demonstrate that the main component is calcium sulfate. Also it was found that CSC/SF/0.5SLCM supports the growth of MC3T3 cells. Thus the preparation of CSC/SF/0.5SLCM was reliable, and the products had good structures, physical properties and biocompati-bility, appearing to be a promising bone substitute material.     

腐植酸/丙烯酸型吸水性树脂的合成及吸水性能研究

以腐植酸、丙烯酸为单体,丙三醇为交联剂,采用溶液聚合法合成了腐植酸/丙烯酸型吸水性树脂,并考察腐植酸加入量、中和度、交联剂、引发剂用量对吸水倍率的影响。结果表明,各组分含量对合成树脂的吸水倍率影响较大。     

Release behavior and kinetic evaluation of berberine hydrochloride from ethyl cellulose/chitosan microspheres

Novel ethyl cellulose/chitosan microspheres （ECCMs） were prepared by the method of w/o/w emulsion and solvent evaporation. The microspheres were spherical, adhesive, and aggregated loosely with a size not bigger than 5 pm. The drug loading efficiency of berberine hydrochloride （BH） loaded in microspheres were affected by chitosan （CS） concentration, EC concentration and the volume ratio of V（CS）/V（EC）. ECCMs prepared had sustained release efficiency on BH which was changed with different preparation parameters. In addition, the pH value of release media had obvious effect on the release character of ECCMs. The release rate of BH from sample B was only a little more than 30% in diluted hydrochloric acid （dHCl） and that was almost 90% in PBS during 24 h. Furthermore, the drug release data were fitted to different kinetic models to analyze the release kinetics and the mechanism from the microspheres. The released results of BH indicated that ECCMs exhibited non-Fickian diffusion mechanism in dHCI and diffusion-controlled drug release based on Fickian diffusion in PBS. So the ECCMs might be an ideal sustained release system especially in dHCl and the drug release was governed by both diffusion of the drug and dissolution of the polymeric network.