【作者】 赵彬然；

【导师】 薛伟明；

【作者基本信息】 西北大学 ， 化学工艺， 2010， 硕士

【摘要】 载药微球具有提高药物的生物利用度、延长药物的作用时间等优点,因此近年来成为新型控释制剂的研究热点。本文以天然多糖海藻酸钠和壳聚糖为主要载体材料,以临床上常用免疫抑制剂-环孢素为药物模型,采用脉冲电场工艺制备了载环孢素壳聚糖／海藻酸钙微球。对载环孢素壳聚糖／海藻酸钙微球的制备工艺、膜强度、体外释放等进行了详细研究,并进行了初步的应用实验。得到如下结论：1.为了得到小粒径微球,对微球制备的配方进行了研究。原料液中加入表面活性剂能够有效降低原料液的表面张力,提高环孢素在水中的溶解度,这有利于制备小粒径的微球；凝胶浴中加入表面活性剂和适当浓度的NaCl降低了凝胶浴的表面张力,有利于得到较好形态的微球。这些添加剂在短时间内不会对环孢素的稳定性产生影响。2.在加入以上添加剂的基础上,确定了制备微球的最优工艺：Tween20浓度1%(V／V),CsA浓度2g/L,CaCl2浓度30g/L,NaCl浓度80g/L,海藻酸钠浓度10g/L,1631浓度0.1g/L。此工艺条件下制备的微球粒径小而且均匀,并且对于保证高的环孢素包封率具有良好的可靠性和重复性。3.为得到高脱乙酰度壳聚糖,对壳聚糖进行脱乙酰化反应,确定壳聚糖脱乙酰化的最优工艺条件：片状壳聚糖,微波加热时间20min,功率900W,50%(wt／v)NaOH溶液。4.系统研究了成膜条件对载药微球在模拟体液中的强度性能的影响：表面活性剂的添加会提高载药微球的稳定性；壳聚糖膜强度随壳聚糖分子量和溶液pH的增加呈现先减弱后增强的趋势：20万分子量、pH=6.3时,膜强度最好；膜强度随壳聚糖脱乙酰度的升高而增强,DD=94%时最好。5.考察了载药微球在模拟体液中的体外释放过程。释放分四个阶段完成：突释、慢速释放、较快速的稳态释放和缓慢释放阶段。在纯水和生理盐水中释放机制为扩散-溶蚀扩散,在模拟肠液中为骨架溶蚀机制。6.本文还对微球的体内应用做了初步研究,微球通过黏附在小肠壁上来延长在体内的停留时间,通过血药浓度检测也得到微球延长药物作用时间的结论。但在兔眼结膜注射实验中兔眼出现了炎症反应,原因需要进一步研究。更多还原

【Abstract】 Drug-loaded microspheres can improve the bioavilability and extend the drug’s action time, so in recent years it has been the hotpoint of new-model controlled-release preparation.Taking the natural polysaccharide-chitosan and sodium alginate as the main carrier material, the classical immunosuppressants-cyclosporine as the drug model, the mild and efficient Impulsine Electrostatic Technique as the preparation technology, the cyclosporine-loaded Chitosan/Algnate Microspheres are prepared. Its preparation process, membrane strength, and release in vitro are studied in detail. The microspheres have also been applied tentatively.Experimental results show that:1. The formula for making small microsphere has been studied. Adding surfactant in sodium alginate solution can reduce the surface tension of the solution and increase cyclosporine’s solubility, which favor the preparation of small microsphere; Adding surfactant and NaCl in CaCl2 solution can reduce the surface tension of the solution which is helpful to keep microsphere’s shape. It also confirmed that tween20, Hexadecyl trimethyl ammonium Bromide, NaCl will not affect the stability of cyclosporine in a short period of time.2. The optimum conditions to prepare cyclosporine-loaded Chitosan/Algnate Microspheres are as follows:1%(V/V) tween20,2g/L CsA,30g/L CaCl2,80g/L NaCl, 10g/L sodium alginate,0.1 g/L 1631. The conditions can not only ensure the small and uniform grading grain-size, but have good reliability and repeatability in guaranteeing high drug encapsulation ratio.3. In order to get the chitosan with higher DD, the paper studys the process of romoving the acetyl. the optimum conditions should be:flake chitosan,20min, the maximum power of 900W,50%(wt/v)NaOH.4. The effect of membrane formation conditions on the chitosan membrane strength in the simulated body fluid has been systimatically investigated.The microsphere stability has been improved adding the surfactant; As the increase of the molecular weight of chitosan and pH of chitosan solution, the membrane strength becomes weak first and strengthened then.When twenty thousand molecular weight, and pH=6.3, the best membrane strength is got. While the DD of chitosan increase, membrane strength is improved. When the DD is 94%, the stability is the best.5. The release process of the cyclosporine-loaded microspheres in the simulated body fluid is investigated.The whole release has four stages:burst release;low speed release; fast stable release and the last low speed release. Other than the framework erosion mechanism in the simulative intestine juice, in H2O and 0.9%NaCl the release mechanism is erosion-diffusion.6. The paper also study the tentative application in vivo. Drug-loaded microspheres prolong the residence time by adhering the intestinal wall.The conclusion that microsphere can extend the drug’s action time is got from the cyclosporine concentration in blood. But we observed the Eye irritation after subconjunctival injection in rabbits, It still need further study.更多还原