微囊化大鼠胰岛异种移植的实验研究

目的　通过动物实验明确微囊化胰岛是否具有免疫隔离作用。方法　SD大鼠胰腺原位消化 ,Ficoll间断密度梯度离心法纯化、分离胰岛 ,气流吹喷制作海藻酸钠 /聚赖氨酸 /海藻酸钠(APA)微囊化大鼠胰岛 ,比较微囊化与未微囊化胰岛的胰岛素释放试验 ;将微囊化 (实验组 )与未微囊化 (对照组 )大鼠胰岛植入链脲佐菌素 (STZ)诱导的I型糖尿病小鼠中 ,作两组间血糖正常持续时间比较。结果　实验组与对照组的胰岛素释放试验差异无显著性 (P >0 .0 5 ) ;实验组血糖正常持续时间为 2 3～ 6 5d(平均 48d) ,对照组为 3～ 6d(平均 5d) ,两组差异有极显著性 (P <0 .0 1)。已排斥的实验组小鼠腹腔灌洗发现部分微囊化胰岛存活 ,部分已坏死 ,但微囊膜皆完整 ,囊壁无纤维化。结论　微囊具有良好的免疫隔离作用 ,可使胰岛移植物存活时间明显延长。同时推测微囊内移植物死亡与细胞因子、自由基作用或营养不足等有关。     

包裹胰岛微囊的物理性能研究

用３％海藻酸钠及２．２％ＣａＣｌ＿２所制备的微囊在高流速及高浓度的蔗糖溶液冲击下未见破裂，且微囊包裹活细胞经过二小时的剧烈搅拌，亦无损漏。改进法所制备的微囊具有良好的机械强度，其物理性能已达到临床进行包膜胰岛移植治疗糖尿病的要求。     

APA微胶囊免疫隔离生物膜制备中的质量控制

为了优化制备条件, 简化工艺, 控制质量, 本文观测了APA(海藻酸盐-聚赖氨酸-海藻酸盐)微胶囊免疫隔离生物膜制备过程中部分物理因素和化学因素与质量的关系.结果表明: 微囊的粒径与静电微囊发生仪脉冲频率呈负相关; 与推进泵速度呈正相关; 与针头内径呈正相关.随着聚赖氨酸浓度的增加, 膜厚度显著增加.微囊的粒径不随聚赖氨酸成膜反应时间延长而改变, 但影响膜的厚度.柠檬酸钠的液化时间对微囊的粒径与厚度均无明显影响.通过优化制备条件, APA微胶囊免疫隔离生物膜将具有更好的通透性、柔韧性、生物相容性和强度.     

红霉素缓释微囊的制备及其释药机理的研究

本文旨在探讨红霉素微囊的制备及体外缓释机理。以明胶等为囊材,用红霉素制成微囊,研究微囊的厚度及孔隙度对药物释放速率的影响。进行理论分析,与实验结果相符性较好。     

丙戊酸钠缓释片的制备及其释放度的测定

目的 研制丙戊酸钠缓释片并进行体外释放度测定。方法 采用喷雾干燥法制备丙戊酸钠微囊，通过电镜和X-射线衍射等检测方法对微囊进行质量评价。采用永停滴定法测定丙戊酸钠微囊含量及缓释片的体外释放度。结果 喷雾干燥法制备的丙戊酸钠微囊质量较好，所制缓释片体外释放符合一级动力学过程。结论 运用丙戊酸钠微囊制备缓释片的工艺简便、可靠，体外释放证明有明显的缓释作用。     

The release of diazepam from poly(hydroxybutyrate-hydroxyvalerate) microspheres

Microspheres based on a poly(hydroxybutyrate-hydroxyvalerate) copolymer (PHBV) (Mw = 630 kD, 21% mol HV) were loaded with diazepam using different emulsion-solvent evaporation processes. Gelatin was used as a strategy to alter the release profile of the incorporated drug. The mean diameter of microspheres was from 30-40 micron. Drug-release from the microspheres over a 30-day period showed a characteristic triphasic release pattern with an initial burst effect, but was linear over the same period and without a burst effect when gelatin was used as a coating agent. Scanning electron microscopy revealed that the microspheres had different structures depending upon their method of preparation.     

左旋多巴微囊漂浮片的处方优选

摘 要 目的： 优选左旋多巴微囊漂浮片的处方。方法: 高效液相色谱法测定左旋多巴与苄丝肼的含量,以漂浮片释放度得分为指标,采用正交试验优选左旋多巴微囊漂浮片的处方,并对其体外释药特性进行评价。结果: 建立的测定左旋多巴胃内漂浮片中左旋多巴与苄丝肼含量的高效液相色谱法,符合方法学要求。优化的微囊漂浮片处方组成为硬脂酸：主药：丙烯酸树脂：HPMC=2∶5∶2∶1,平均片重为550 mg。验证试验结果表明该微囊漂浮片具有漂浮、缓释、可分剂量使用等特性。结论: 优选出的复方左旋多巴微囊漂浮片处方合理,生产工艺稳定、可行。     

正交实验设计优化岩白菜素微囊的制备工艺

目的优化岩白菜素微囊的制备工艺,并对制备的岩白菜素微囊进行质量评价。方法以明胶为囊材,单凝聚法制备岩白菜素微囊,通过正交实验设计优化其制备工艺,并对包封率、载药量、平均粒径、体外溶出率进行研究。结果明胶制备岩白菜素微囊的最佳工艺条件为:明胶质量分数为6%,囊心囊材质量比为1∶2,搅拌速度为750r·min^-1。此最佳工艺制备的岩白菜素微囊包封率为75.90%,载药量为23.09%,体外溶出度测定30min为28.6%,12h累计释放达到90%以上。结论以最佳工艺条件制备岩白菜素微囊工艺稳定,包封率高,同时体外释放实验表明,该微囊具有较好的缓释作用。     

原位聚合法制备脲醛树脂微囊的处方工艺研究

目的 确定制备脲醛树脂微囊的最佳处方和工艺,特别是包括抗微囊粘连效果最佳的抗黏剂和添加剂.方法 采用原位聚合一步法制备微囊,考察系统稳定剂种类及用量、多种抗粘剂及添加剂对成囊过程及囊粒粒径的影响.结果 以1.5％PVA作为系统稳定剂,在pH值为3.5、搅拌速度为700r/min的工艺条件下,制备的微囊粒径均匀、不粘连.反应结束后调节系统pH值为7,加入固化剂间苯二酚和增稠剂黄原胶,具有良好抗粘连效果.结论 系统稳定剂的作用是使芯材形成稳定油滴,促使囊材包覆其表面上,最佳的系统稳定剂可降低囊材自身成核的几率.     

A new approach in gastroretentive drug delivery system using cholestyramine

We prepared cellulose acetate butyrate (CAB)-coated cholestyramine microcapsules as a intragastric floating drug delivery system endowed with floating ability due to the carbon dioxide generation when exposed to the gastric fluid. The microcapsules also have a mucoadhesive property. Ion-exchange resin particles can be loaded with bicarbonate followed by acetohydroxamic acid (AHA) and coated with CAB by emulsion solvent evaporation method. The drug concentration was monitored to maintain the floating property and minimum effective concentration. The effect of CAB: drug-resin ratio (2:1, 4:1, 6:1 w/w) on the particle size, floating time, and drug release was determined. Cholestyramine microcapsules were characterized for shape, surface characteristics, and size distribution; cholestyramine/acetohydroxamic acid interactions inside microcapsules were investigated by X-ray diffractometry. The buoyancy time of CAB-coated formulations was better than that of uncoated resin particles. Also, a longer floating time was observed with a higher polymer:drug resin complex ratio (6:1). With increasing coating thickness the particle size was increased but drug release rate was decreased. The drug release rate was higher in simulated gastric fluid (SGF) than in simulated intestinal fluid (SIF). The in vivo mucoadhesion studies were performed with rhodamine-isothiocyanate (RITC) by fluorescent probe method. The amount of CAB-coated cholestyramine microcapsules that remained in the stomach was slightly lower than that of uncoated resin particles. Cholestyramine microcapsules were distributed throughout the stomach and exhibited prolonged gastric residence via mucoadhesion. These results suggest that CAB-coated microcapsules could be a floating as well as a mucoadhesive drug delivery system. Thus, it has promise in the treatment of Helicobacter pylori .