节点文献
SPG膜乳化法制备单分散性载药微囊
【作者】 王超宝;
【导师】 杨亚楠;
【作者基本信息】 长春工业大学 , 高分子化学与物理, 2010, 硕士
【摘要】 在药物控释体系中,大多数的多肽、蛋白质类药物都是水溶性的,而作为包埋材料的生物可降解高分子则是油溶性的,这给载药微囊的制备造成了很大的困难。水包油包水(W/O/W)复乳溶剂蒸发法的出现有效的解决了该问题,在药物控释领域得到了广泛的应用。在制备过程中,通常采用超声、均质或机械搅拌等手段制备水包油包水(W/O/W)型双乳液。但无论采用上述何种制备方法,制备过程中都容易出现包封率低、微球中药物释放的突释及药物在微囊内聚集或失活等问题,限制了该方法在实际中的应用。上世纪90年代开发的膜乳化技术有效的解决了上述问题。膜乳化技术是一种新型的乳液制备手段,具有能耗低、操作简单、重复性好、得到的产品粒径分布窄并可有效的对产品尺寸进行控制等明显优点。首先,论文为了考察实验条件对制备载药微囊的影响,研究了乳化剂种类、乳化剂浓度以及有机溶剂的密度等因素对初乳稳定性的影响,以及膜乳化压力、搅拌速度和固化时间对载药微囊包封率的影响,并对其体外释放行为进行了考察。本章实验均以乙交酯和丙交酯的无规共聚物(PLGA)为载体材料,BSA为模型蛋白。分析表明,随着膜乳化压力的增加,包封率会不同程度的降低;搅拌速度的增加也会导致包封率的降低;固化时间为5h时,包封率最高。而后,论文还研究了初乳液滴尺寸对膜乳化法制备载药微囊性质的影响。通过实验,我们发现初乳液滴尺寸对载药胶囊的表面形态、包封率及释放行为均有重要的影响。结果表明,随着初乳液滴尺寸的减小,载药微球表面孔洞的直径也随之减少,表面变光滑,包封率逐渐提高,最大包封率达到90%以上;初乳液滴尺寸越小,载药微囊的突释现象越不明显,体外释放行为越平稳。其次,论文采用PLGA为载体材料,BSA为模型蛋白,采用膜乳化技术结合水包油包水(W/O/W)复乳溶剂蒸发法制备BSA载药微囊。结果表明:膜乳化法制备的载药微囊的包封率明显高于机械搅拌法,最高可达93.72%;采用膜乳化技术,可以有效的缓解载药微囊的突释现象,1个月内的累计释放量可以达到80%以上。最后,论文对膜乳化法结合水包油包固体(S/O/W)法制备载胰岛素微囊进行了探索。首先,实验采用等电点沉淀法成功制备出了胰岛素纳米颗粒,其粒径分布范围主要在30-50nm之间;其次,采用S/O/W法结合膜乳化技术制备胰岛素载药微囊,并对得到的载药微囊进行表征,结果表明:采用S/O/W法制备的载药微囊表面的孔洞相对较少,表面比较光滑;该方法制备的载药微囊包封率较低,最高仅能达到71.55%;与此同时,载药微囊的突释量较低,从整个释放行为上看,该方法制备的载药微囊的释放行为可持续两周左右。
【Abstract】 In the drug delivery system, a majority of polypeptides and protein drugs are water-soluble, but the biodegradable polymers, as the carrier material, are oil-soluble, it is very difficult for the preparation of drug-loaded microcapsules. The emergence of Water-oil-water (W/O/W) multiple emulsion-solvent evaporation method effectively solved the problem, had been widely used in the field of drug delivery system. Usually, the water-oil-water (W/O/W) multiple emulsions were prepared by ultrasound, homogenization or mechanical stirring. However, the problems of the lowly encapsulation efficiency, the burst release of drug and the cohesion and inactivation of drug were frequently appeared, no matter what kind of the above-mentioned preparation methods were used. In the nineties of the 20th century, the emergence of Shirasu Porous Glass(SPG) membrane emulsification technique effectively solved the above problems. Membrane emulsification technology is a new type of emulsion preparation methods, with the obvious advantages of low energy consumption, simple operation, reproducibility, narrow size distribution of the obtained products and the controlled size of products.Firstly, the paper investigated the influences of experimental conditions on BSA-loaded microspheres. The researches as follow:Firstly, the paper investigated the influences of the type of emulsifier, emulsifier concentration and the oil phase density on primary emulsion stability. The effect of press, stirrer speed and solidification time on encapsulation efficiency and the release behavior of BSA-loaded microcapsules were studied. PLGA and BSA were used in the experiment of this chapter. It was demonstrated that the encapsulation efficiency reduced when press was increased; when stirrer speed was more than 200rpm, the encapsulation efficiency also reduced by the increase of stirrer speed; the encapsulation efficiency was highest when solidification time was 5 hours. The influences of primary emulsion droplets size on BSA-loaded microspheres were investigated. It was demonstrated that primary emulsion droplets size had an important influence on microspheres surface morphology, encapsulation efficiency and release behavior. When primary emulsion droplets size was reduced, the diameter of holes on microspheres wall also was reduced, the encapsulation efficiency was increased, the highest encapsulation efficiency reached 90%, and the initial release was decreased.Secondly, BSA-loaded microcapsules were prepared by combining a Shirasu Porous Glass(SPG) membrane emulsification technique and multiple emulsion-solvent evaporation method with poly(lactic-co-glycolic acid)(PLGA) as the carrier material. Compared with mechanical stirring method, the encapsulation efficiency of microspheres which prepared by membrane emulsification technique was obviously higher, the highest encapsulation efficiency reached 93.72%. Initial release was lower when microcapsules were prepared by Shirasu Porous Glass (SPG) membrane emulsification technique, and the total release achieved 80% in a month.Lastly, the preparation of insulin-loaded microcapsules by combining a Shirasu Porous Glass(SPG) membrane emulsification technique and solid-oil-water (S/O/W) method was investigated. By using methods of isoelectric points deposition, insulin nanoparticles was successfully achieved within the range of 30-50nm. Insulin-loaded microcapsules were prepared by combining a Shirasu Porous Glass(SPG) membrane emulsification technique and solid-oil-water (S/O/W) method. It was demonstrated that the amount of holes on microspheres wall was relatively small by using S/O/W method; the encapsulation efficiency was relatively low by using S/O/W method, the highest encapsulation efficiency only reached 71.55%; initial release was relatively lower by using S/O/W method, in view of the overall situation, the behavior of drug release lasted for two weeks.
【Key words】 biodegradable polymers; controlled release of drug; Bovine Serum Albumin; insulin; membrane emulsification;