共查询到19条相似文献,搜索用时 143 毫秒
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基于HPMCP包覆介孔SBA-15的pH敏感药物缓释系统 总被引:5,自引:0,他引:5
以肠溶性包衣材料羟丙甲纤维素邻苯二甲酸酯(HPMCP)为原料,在负载法莫替丁(Famo)的SBA-15药片表面包覆聚合物膜,成功制备了一种新型的pH敏感药物缓释系统, 并考察了此缓释系统在不同pH释放环境中的释放行为. 结果表明: 在模拟胃液中(SGF, pH=1.2),HPMCP能致密包覆在药片表面,从而明显延缓Famo的释放速度;而在模拟肠液中(SIF, pH=7.5),HPMCP能够迅速溶于缓释溶液中,因而对Famo释放速度的影响甚微. 因此,可以将这种新型智能药物缓释系统应用于肠道靶向给药. 相似文献
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含巯基/二硫键聚合物生物材料具有多种良好的性能,作为药物、基因等的释放载体在生物医学领域具有广泛的应用前景。随着基因工程和组织工程的发展,含巯基/二硫键聚合物生物材料的可生物降解性得到高度重视,而怎样改善其降解性能成为限制其应用的关键因素。由于二硫键在细胞外环境里保持稳定,在细胞溶质的还原环境中容易发生断裂,因此在制备新型基因、药物等释放载体上,二硫键充当了重要的角色,它的引入为聚合物生物材料的生物降解性能的设计与改善提供了一条重要的途径。本综述重点以聚合物水凝胶、聚合物微胶束、囊泡等为例,从巯基/烯的光聚合反应、Michael加成反应、氧化还原反应的角度,介绍了巯基/烯在聚合物中形成二硫键的不同途径的研究进展,并详细论述了基因载体、蛋白质载体、小分子药物载体三种还原敏感型材料的制备、表面修饰和改性的进展情况,进一步强调含巯基/二硫键聚合物生物材料的研究在生物医学领域应用的重要性。 相似文献
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分别利用化学法和酶促法合成了三种药物(萘普生、酮洛芬、布洛芬)乙烯酯和葡萄糖丁二酸乙烯酯(6-O-乙烯丁二酰-D-葡萄糖)两种聚合单体, 通过两种单体的自由基聚合反应制备了具有较高分子量的含糖聚合物前药. 通过IR、NMR对聚合物的结构进行了表征, 用GPC测定共聚物分子量. 含糖聚合物前药的体外释放研究表明, 将小分子原药制备成含糖聚合物前药后, 药物的释放时间大大延长, 达到了缓释的目的. 三种含糖聚合物的药物释放研究表明, 酮洛芬含糖高分子前药的药物释放速率较快, 萘普生含糖高分子前药的药物释放速率较慢. 不同的pH条件下的含糖聚合物的药物释放研究表明, 碱性环境下的药物释放较快, 酸性环境下的药物释放较慢. 相似文献
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生物可降解5-氟尿嘧啶载药微球的制备及性能研究 总被引:5,自引:0,他引:5
5-氟尿嘧啶(5-Fu)为水溶性嘧啶类抗代谢药,是治疗实体肿瘤的首选药物.但5-Fu毒性很大,血浆中停留半衰期t1/2仅为10~20min.为了减少氟尿嘧啶的毒副作用并提高药物利用率,可以将其制成聚合物载药微球.聚酯类高分子是较为常用的生物降解型药物载体材料,其中聚乳酸(PLA)及其共聚物具有良好的生物相容性及生物可降解性,常被广泛应用于药物缓释材料, 相似文献
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生物降解型聚氨酯材料的研究:Ⅰ.控制释放化肥包覆材料 总被引:13,自引:0,他引:13
以树皮为原料,合成了生物降解型聚氨酯泡沫材料,并考察了其作为化肥缓释的包膜材料对常用氮肥硫酸铵的控制释放性能。研究结果表明,以水作为发泡剂的多孔性聚氨酯包裹硫铵后,在模拟自然界雨淋的作用下,释放曲线大致呈抛物线型。释放的速度与所包裹的硫铵量关系不大;发泡时水的比例越高,释放速度越快;颗粒越大,释放越慢;树皮的比例越高,释放越慢。对包膜材料的生物降解性方面的初步实验结果表明:该材料在土壤中能够自然降 相似文献
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A carbon dioxide (CO(2))-based microencapsulation technique was used to impregnate indomethacin, a model drug, into biodegradable polymer nanoparticles. Compressed CO(2) was emulsified into aqueous suspensions of biodegradable particles. The CO(2) plasticizes the biodegradable polymers, increasing the drug diffusion rate in the particles so that drug loading is enhanced. Four types of biodegradable polymers were investigated, including poly(d,l-lactic acid) (PLA), poly(d,l-lactic acid-co-glycolic acid) (PLGA) with two different molar ratios of LA to GA, and a poly(d,l-lactic acid-b-ethylene glycol) (PLA-PEG) block copolymer. Biodegradable nanoparticles were prepared from polymer solutions through nonsolvent-induced precipitation in the presence of surfactants. Indomethacin was incorporated into biodegradable nanoparticles with no change of the particle size and morphology. The effects of a variety of experimental variables on the drug loadings were investigated. It was found that the drug loading was the highest for PLA homopolymer and decreased in PLGA copolymers as the fraction of glycolic acid increased. Indomethacin was predicted to have higher solubility in PLA than in PLGA based on the calculated solubility parameters. The drug loading in PLA increased markedly as the temperature for impregnation was increased from 35 to 45 degrees C. Drug release from the particles is a diffusion-controlled process, and sustained release can be maintained over 10 h. A simple Fickian diffusion model was used to estimate the diffusion coefficients of indomethacin in the biodegradable polymers. The diffusion coefficients are consistent with previous studies, suggesting that the polymer properties are unchanged by supercritical fluid processing. Supercritical CO(2) is nontoxic, easily separated from the polymers, can extract residual organic solvent, and can sterilize biodegradable polymers. The CO(2)-based microencapsulation technique is promising for the production of drug delivery devices without the use of harmful solvents. 相似文献
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Chang-Jiang Pan Jia-Ju Tang Ya-Jun Weng Jin Wang Nan Huang 《Colloids and surfaces. B, Biointerfaces》2009,73(2):199-206
In the present study, the different drug-eluting controlled biodegradable polymer coatings were fabricated on stainless steel stents. The coatings were not only uniform and smooth but also had excellent mechanical property. The drug release profiles of drug-eluting stents were studied in detail in this study. Depending on the drug type, different drug-eluting stents exhibited different drug release profile. There were two basic release profiles for different drug-eluting stents, i.e., two-phase release profile with burst release or linear release profile without burst release. Incorporating heparin in the rapamycin or curcumin eluting stents can improve the average drug release rate of both and the burst release of rapamycin. The average drug release rate increased with the increase of drug loading but was not proportional to increase of the ratio of drug/polymer. Fabricating the control release layer on rapamycin-eluting stent surface can prevent the burst release of rapamycin and prolong the release period of rapamycin. All results showed that the drug release profile of drug-eluting stents depends on many parameters including drug type, ratio of drug/polymer, and drug carrier properties. 相似文献
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药物和蛋白质与聚己内酯分层复合纳米纤维的微观结构与力学特性 总被引:11,自引:4,他引:7
应用同轴共纺技术制得芯质和表层为两种不同材料的分层复合纳米纤维.分别以乙酰螺旋酶素片剂和明胶蛋白质为芯质材料,以可生物降解的聚己内酯作为表层材料,研究了这种分层复合纳米纤维的微观结构与力学特性.结果表明,尽管药物与表层聚合物材料的溶解溶剂互不相同,但仍可以将药物包覆在壁厚小于100nm的超细纤维中.这种纤维可用作体内手术伤口缝合线或大面积创伤如烧伤伤口的敷布.在实验范围内,纤维膜的力学性能随芯质内溶质含量的提高而降低. 相似文献
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Romanski FS Winkler JS Riccobene RC Tomassone MS 《Langmuir : the ACS journal of surfaces and colloids》2012,28(8):3756-3765
In recent years, production and characterization of anisotropic particles has become of interest in a wide range of scientific fields including polymer chemistry, drug delivery, electronics, energy, and nanotechnology. In this work, we demonstrate a novel formulation for production of anisotropic particles via an internal phase separation of biodegradable components. Specifically, binary mixtures of biodegradable polymers poly(lactic-co-glycolic acid), polycaprolactone, and biodegradable lipid Precirol (glyceryl palmitostearate) were dissolved in dichloromethane, emulsified, and prepared into anisotropic particles using a modified solvent evaporation technique. During the slow evaporation process the components self-assembled into anisotropic particles with distinct morphologies. Polymer/polymer formulations resulted in compartmentalized anisotropic heterodimer particles, while polymer/lipid combinations yielded "ice cream cone" shaped particles. It was found that addition of certain active pharmaceuticals resulted in an altered, pox-like segregation at the particle surface of polymer/polymer formulations. The anisotropic nature of the particles was subsequently characterized using optical microscopy, scanning electron microscopy, zeta potential, electrophoresis, and X-ray diffraction. Successful formulations presented here may potentially be employed as multicompartmental drug carriers with staggered drug release rates or alternatively as a colloidal excipient for an arsenal of pharmaceutical applications. 相似文献
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A simple aliphatic modification demonstrated how to turn a water-soluble biodegradable triblock copolymer synthesized from PEG, L-lactide, and epsilon-caprolactone into a thermoreversible polymer of which aqueous solution underwent a sol-to-gel phase transition upon a mild temperature rise. Thermogelling behavior of the aliphatically modified polymer was dependent on the degree of aliphatic modification and polymer concentration. When the polymer solutions were subcutaneously injected into rats, immediate depot formation has been observed. The polymeric gel depots have lasted for two weeks in vivo. This aliphatically modified thermogelling polymer can find applications in drug delivery. 相似文献
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生物高分子材料在现代药物传递系统中不仅起着载体的作用,而且还影响和控制药物的缓释机理。文章为第一部分,主要介绍生物高分子材料在药物传递系统中的降解机理与表征方法。 相似文献
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A synthesized graft polymer is used as a biodegradable polymer for an in situ gel-forming injectable implant system. The amphiphilic character of the polymer in the graft structure lowered the viscosity of the polymer solution, which enabled easy injection. A micro-sized gel can be obtained with this system, which has not been found for previous in situ gel-forming systems with poly[(D,L-lactide)-co-glycolide] copolymer. In addition, a protein particle embedded gel exhibits good in vitro drug release performance as a result of the enhanced stability and shorter diffusion length. 相似文献