尺寸均一的壳聚糖微球的制备及其作为胰岛素控释载体的研究

采用新型微孔膜乳化技术制备了载胰岛素的壳聚糖微球。研究表明,要制备粒径均一的壳聚糖微球,必须将亲水性膜修饰成疏水性;制得的微球粒径和所采用的膜孔径之间存在很好的线性关系,使得微球粒径可控;以胰岛素为模型药物,主要考察了交联剂用量和交联时间对微球表面形态、药物包埋率和微球体外释药特性的影响。结果表明当氨基与醛基的摩尔比为1∶0.7、交联时间为1h时,所得载药微球的包埋率最高,随着戊二醛用量的增加和交联时间的延长,药物体外释放速率减慢。     

姜黄素壳聚糖微球的制备及其在体内外释放度的研究

目的:研究响应面法优化姜黄素壳聚糖微球制备的工艺参数,提高姜黄素的溶出度.方法:采用离子交联法制备姜黄素缓释微球,以微球的载药量和包封率为考察指标,采用星点设计考察配制壳聚糖的醋酸浓度、药物载体的比例以及交联剂浓度对微球制备工艺的影响,对结果进行二次多项式拟合,并根据最佳数学模型进行预测.结果:姜黄素壳聚糖微球最优制备工艺参数为:醋酸的浓度为1％,载体药物比例为0.83,交联剂的浓度为0.15％,载药量和包封率的预测值和理论值偏差分别为0.47％和3.2％.结论:响应面法优化姜黄素壳聚糖微球制剂处方具有很好的预测性,体内外药物释放度研究表明,最优条件下制备的微球可以在提高姜黄素溶出度的前提下缓慢释放达12h.     

拟除虫菊酯微胶囊的制备

以海藻酸钠、壳聚糖为壁材,氯氟氰菊酯为芯材,通过复凝聚法制备微胶囊。用红外光谱确定复合膜的形成,光学显微镜观察微胶囊的分散性和规整度,气相色谱法测定包封率。考察油水相体积比、搅拌速度、乳液稀释水用量及壳聚糖的浓度对氯氟氰菊酯微胶囊化的影响。结果表明,最佳的实验条件是油水相体积比为1∶10、搅拌速度为1300 r/min、乳液与水体积比为1∶1.2,壳聚糖浓度为0.1%。制备的微胶囊包封率可以达到80.3%。     

均匀设计法优化硝酸咪康唑微球的制备工艺

目的：以均匀设计法筛选优化硝酸咪康唑苹果酸化壳聚糖微球的制备工艺,提供可控性及预测性,并对微球稳定性和药物释放规律进行研究。方法：采用乳化交联法制备微球。采用U5（53）试验表进行试验,分别考察各处方的制备的微球的形态和粒径、载药量和包封率。利用SPSS软件进行多元线性回归拟合,得到方程及优化工艺条件。结果：优化方程的预测值与实验值之间有较好的吻合性。制备出的微球可以在室温（25℃）条件下保存;微球的药物释放动力学可用一级动力学方程来描述。结论：本实验通过均匀设计法优化硝酸咪康唑微球的制备工艺预测性好且制备的微球性能良好。     

IBDV丝素蛋白/壳聚糖DNA微球疫苗的制备及免疫原性分析

为了制备传染性法氏囊病病毒(Infectious bursal disease virus,IBDV)DNA微球疫苗,并评价其免疫效果。以丝素蛋白(Silk fibroin,SF)/壳聚糖(Chitosan,CS)为壁材,IBDV的VP2/4/3 DNA疫苗为芯材,通过戊二醛和Na2SO4介导的乳化交联技术,制备出SF/CS复合微球疫苗,然后经肌肉注射14日龄非免疫鸡,2周后加强免疫一次,酶联免疫法(ELISA)定期监测鸡血清的IBDV抗体,以研究微球化疫苗的免疫原性。结果显示:戊二醛介导交联方法影响荷载DNA疫苗的活性,而Na2SO4介导的交联方法操作简单且不影响荷载DNA活性;建立了以壳聚糖浓度0.5%(pH 5.0)、丝素蛋白浓度0.6%,质粒DNA 500μg/mL溶解在2%Na2SO4溶液中的工作条件;SF-CS复合微球DNA疫苗荷载率89.14%,大小1.98μm,对DNaseⅠ的消化有保护作用。免疫后的抗IBDV血清ELISA抗体的检测显示,微球免疫组总体高于质粒疫苗免疫组(P0.05),而且SF/CS复合微球组免疫反应要略高于单纯CS包被的抗原组。研究表明,丝素蛋白/壳聚糖作为微球佐剂能提高IBDV DNA疫苗的临床免疫效果,有很好的应用前景。     

均匀设计法优化壳聚糖微球的制备工艺

本实验采用均匀设计法优化甘草酸壳聚糖微球的制备工艺,提供可控性及预测性,并对微球稳定性和药物释放规律进行研究.实验方法是运用乳化交联法制备微球,利用SPSS软件进行多元线性回归拟合,得到方程及优化工艺条件.优化方程的预测值与实验值之间有较好的吻合性.制备出的微球可以在室温(15～25 ℃)或低温(4 ℃)条件下保存,微球可采用60Co辐射灭菌;微球的药物释放动力学可用一级动力学方程来描述.由此,本实验通过均匀设计法优化甘草酸壳聚糖微球的制备工艺预测性好且制备的微球性能良好.     

壳聚糖-海藻酸钠靛玉红自微乳缓释微囊制备、评价及体外释放的研究

以靛玉红自微乳为囊心物,壳聚糖和海藻酸钠为囊材,采用复凝聚法制备壳聚糖-海藻酸钠靛玉红自乳化缓释微囊,通过正交实验和单因素考察确定壳聚糖-海藻酸钠靛玉红缓释微囊的最佳制备工艺。并以载药量、包封率为评价指标对其进行质量评价,同时以体外释放度评价其释药性能。壳聚糖-海藻酸钠靛玉红缓释微囊的最佳工艺是海藻酸钠的浓度为1.5%,靛玉红自微乳体积、海藻酸钠体积、壳聚糖质量三者比例为1∶1∶0.5,氯化钙浓度的最佳浓度为2.0%。采用该工艺制备的微囊载药量为0.0416%、包封率为79.2%,体外释放24 h累积释放率为(97.1±2.68)%。该微囊的释放符合Higuchi方程和一级释药模型,具有较好的缓释作用。     

交联壳聚糖微球固定化β-葡萄糖苷酶工艺研究

目的:以戊二醛交联壳聚糖微球为载体,通过共价连接反应固定化β-葡萄糖苷酶.方法:以固定化酶比活和酶活回收率为目标,采用单因素方法优化固定化工艺、微球制备条件.结果:微球最佳制备条件:2.5%壳聚糖,2%乙酸,7.5%氢氧化钠,氢氧化钠:乙醇(v/v)=1:1.最佳固定化工艺为:0.1g壳聚糖微球在20mL 3%戊二醛溶液中50℃交联2h.加酶量为7 388mU/g干球,25℃吸附24h.固定化酶比活为6 188mU/g干球,酶活回收率为95.4%.结论:交联壳聚糖微球共价连接法可有效固定化β-葡萄糖苷酶.     

人工软骨支架中TGF-β1缓释壳聚糖微球对ATDC-5细胞生长的促进作用

为了提高本课题组前期构建的Ⅱ型胶原蛋白-透明质酸-硫酸软骨素的人工三维软骨支架对软骨细胞生长的促进作用,采用乳化交联法以壳聚糖为原料,加入细胞转化生长因子TGF-β1,并通过真空冷冻干燥技术制备了包裹TGF-β1的壳聚糖微球。然后分别将其与空白壳聚糖微球整合进软骨支架中,并接种小鼠软骨细胞ATDC-5,通过观察细胞生长状态来评价缓释微球在人工软骨支架中对软骨细胞生长是否具有促进作用。结果显示所制得的壳聚糖微球球体表面光滑,分散均匀,直径在100 nm左右,吸水率良好可达983.73%±4.38%,抗酶解作用较强,第28天时降解率仅达到51.0%±1.8%。由TGF-β1累积释放曲线可知TGF-β1在开始的24 h内释放最快,之后逐渐减慢,在120 h之后进入平台期,具有缓释效果。MTT试验以及荧光染色试验充分表明,由Ⅱ型胶原蛋白、透明质酸以及硫酸软骨素构建的三维软骨支架适合ATDC-5细胞的生长增殖,并且壳聚糖微球对TGF-β1的缓释能够显著促进细胞的生长。     

酮戊二酸改性壳聚糖微球的制备及其对来氟米特的缓释

采用反相悬浮法制备交联壳聚糖微球,再与α-酮戊二酸反应生成Schiff碱,以NaBH_4还原制得改性壳聚糖微球.用FT-IR,SEM和XRD进行表征.并以来氟米特(LEF)为模型药物,考察了其缓释效果.结果显示:微球对药物的最大包封率为94%,载药量为62%,在缓释初期2 h内微球平均释放药量的16%,后期则呈现缓慢释放的趋势.本论文采用的微粒的药物承载量和释放速度既保证了药物的药效又降低了药物释放速率过快引起的对人体的不良反应.     

The study of gelation kinetics and chain-relaxation properties of glutaraldehyde-cross-linked chitosan gel and their effects on microspheres preparation and drug release

The effects of gelation kinetics and chain-relaxation properties of glutaraldehyde-cross-linked chitosan gel on microspheres preparation or drug release were studied. The rate of gelation is zero order corresponding to the chitosan concentration but non-zero order corresponding to the glutaraldehyde concentration. It was suggested that the cross-linking reaction was mainly dominated by the concentration of small molecule reactant, glutaraldehyde. The relaxation of an entangled polymer chain in a gel network as a result of the swelling of cross-linked chitosan hydrogel was investigated by the stress–strain determination. The higher the cross-linking density of chitosan hydrogel, the lower the swelling ability of chitosan hydrogel due to the slower relaxation rate of polymer chain, which then results in the decreased drug-release rate.     

PLGA微球复合明胶组织工程支架缓释蛋白药物的研究

目的：研究PLGA微球复合明胶支架对蛋白药物的释放影响。方法：将模型蛋白BSA通过复乳法制备成缓释PLGA微球,然后将微球埋置于明胶支架中,形成担载蛋白的PLGA微球复合明胶组织工程支架。考察复合支架体外蛋白释放行为,并用MicroBCA法定量测定释放的BSA量,采用β-半乳糖苷酶催化ONPG的方法检测制备前后蛋白的活性,并与不含PLGA微球直接担载蛋白的支架做对照。结果：PLGA微球复合支架蛋白的包封率能达到73．2％,其中第一天释放20％,对蛋白活性的保持达到70％以上。结论：微球复合明胶支架可以改善一般组织工程支架蛋白药物的突释,提高蛋白药物在制剂,贮存,释放过程中的稳定性。     

Glutaraldehyde and glyoxal cross-linked chitosan microspheres for controlled delivery of centchroman

Glutaraldehyde and glyoxal cross-linked microspheres were prepared using chitosan with different molecular weights (MWs) and degrees of deacetylation (DDAs) for sustained release of centchroman under physiological conditions. The DDA in chitosan was determined by different methods, and the samples were categorized as chitosan with low (48%), medium (62%), and high (75%) DDA. The size and shape of the microspheres were determined by scanning electron microscopy (SEM), and hydrophobicity was determined by adsorption of Rose Bengal dye on microspheres cross-linked with glutaraldehyde or glyoxal. The effect of MW, DDA, and degree of cross-linking in microspheres was studied on the degree of swelling, as well as by the loading and release of centchroman. The glyoxal cross-linked microspheres were more compact and hydrophobic and showed better sustained release in companion to chitosan microspheres and glutaraldehyde cross-linked microspheres. The linear fractional release of centchroman with the square root of time indicated a Fickian behavior of centchroman, and the microspheres also showed zero-order release kinetics for centchroman.     

Evaluation of mucoadhesive properties of chitosan microspheres prepared by different methods

The mucoadhesive properties of chitosan microspheres prepared by different method were evaluated by studying the interaction between mucin and microspheres in aqueous solution. The interaction was determined by the measurement of mucin adsorbed on the microspheres. A strong interaction between chitosan microspheres and mucin was detected. The intensity of the interaction was dependent upon the method of preparation of chitosan microspheres and the amount of mucin added. The extent of mucus adsorption was proportional to the absolute values of the positive zeta potential of chitosan microspheres. The zeta potential in turn was found to be dependent upon the method of preparation of microspheres. The adsorption of type III mucin (1% sialic acid content) was interpreted using Freundlich or Langmuir adsorption isotherms. The values ofr ² were greater for Langmuir isotherm as compared with Freundlich isotherm. The adsorption of a suspension of chitosan microspheres in the rat small intestine indicated that chitosan microspheres prepared by tripolyphosphate cross-linking and emulsification ionotropic gelation can be used as an excellent mucoadhesive delivery system. The microspheres prepared by glutaraldehyde and thermal cross-linking showed good stability in HC1 as compared with microspheres prepared by tripolyphosphate and emulsification ionotropic gelation.     

装载于PLGA中的5-氟尿嘧啶缓释微球的制备及其体外释放的研究

目的：研究装载于不同分子量的PLGA中的5-氟尿嘧啶微球的制备方法及其在体外条件下的缓释行为。方法：以水包油包固复乳法将5-氟尿嘧啶包裹在高分子聚乳酸-聚羟基乙酸共聚物（PLGA）中,形成缓释微球,考察其大小,外观,包封率等理化性质,以紫外分光光度法为检测方法研究其体外释放行为。结果：经扫描电子显微镜观察,所制备的微球形态完整,大小较均匀。具有一定得包封率和载药量,体外释放研究表明其处方1和处方2的缓释时间为8天和23天。结论：以水包油包固复乳法制备的PLGA 5-氟尿嘧啶微球能够达到缓释的目的。     

Evaluation of Ionotropic Cross-Linked Chitosan/Gelatin B Microspheres of Tramadol Hydrochloride

Microspheres of tramadol hydrochloride (TM) for oral delivery were prepared by complex coacervation method without the use of chemical cross-linking agents such as glutaraldehyde to avoid the toxic reactions and other undesirable effects of the chemical cross-linking agents. Alternatively, ionotropic gelation was employed by using sodium-tripolyphosphate as cross-linking agent. Chitosan and gelatin B were used as polymer and copolymer, respectively. All the prepared microspheres were subjected to various physicochemical studies, such as drug–polymer compatibility by thin layer chromatography (TLC) and Fourier transform infrared (FTIR) spectroscopy, surface morphology by scanning electron microscopy, frequency distribution, drug entrapment efficiency, in vitro drug release characteristics and release kinetics. The physical state of drug in the microspheres was determined by differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). TLC and FTIR studies indicated no drug–polymer incompatibility. All the microspheres showed initial burst release followed by a fickian diffusion mechanism. DSC and XRD analysis indicated that the TM trapped in the microspheres existed in an amorphous or disordered-crystalline status in the polymer matrix. From the preliminary trials, it was observed that it may be possible to formulate TM microspheres by using biodegradable natural polymers such as chitosan and gelatin B to overcome the drawbacks of TM and to increase the patient compliance.     

Preparation and characterization of sodium hexameta phosphate cross-linked chitosan microspheres for controlled and sustained delivery of centchroman

The cross-linked microspheres using chitosan with different molecular weights and degree of deacetylation have been prepared in presence of sodium hexameta polyphosphate (SHMP) as physical cross-linker. The degree of cross-linking through electrostatic interactions in chitosan microspheres has been evaluated by varying the charge density on chitosan and varying degree of dissociation of sodium hexameta polyphosphate by solution pH. The degree of deacetylation and molecular weight of chitosan has controlled electrostatic interactions between hexameta polyphosphate anions and chitosan, which played significant role in swelling, loading and release characteristics of chitosan microspheres for centchroman. The microspheres prepared by hexameta polyphosphate anions cross-linker were compact and more hydrophobic than covalently cross-linked microspheres, which has been attributed to the participation of all amino groups of chitosan in physical cross-linking with added hexameta polyphosphate anions. The microspheres prepared under different experimental conditions have shown an initial step of burst release, which was followed by a step of controlled release for centchroman. The extent of drug release in these steps has shown dependence on properties of chitosan and degree of cross-linking between chitosan and added polyanions. The degree of swelling and release characteristics of microspheres was also studied in presence of organic and inorganic salts, which shown significant effect on controlled characteristics of microspheres due to variations in ionic strength of the medium. The initial step of drug release has followed first order kinetics and become zero order after attaining an equilibrium degree of swelling in these microspheres. The microspheres prepared using chitosan with 62% (w/w) degree of deacetylation and molecular weight of 1134 kg mol⁻¹ have shown a sustained release for centchroman for 50 h at 4% (w/w) degree of cross-linking with SHMP.     

Chitosan microcapsules loaded with either miconazole nitrate or clotrimazole,prepared via emulsion technique

In this paper, a simple and versatile coacervation technique has been developed by using an ultrasound-assisted oil/water emulsion method for the preparation of antifungal agent-loaded microcapsules. Two types of chitosan microcapsules are successfully prepared. The mean particle size of the chitosan/miconazole nitrate microcapsules is 2.6 μm and that of the chitosan/clotrimazole microcapsules is 4.1 μm. The encapsulation efficiency of the chitosan/miconazole nitrate microcapsules (77.58–96.81%) is relatively higher than that of the chitosan/clotrimazole microcapsules (56.66–93.82%). The in vitro drug release performance of the microcapsules shows that the chitosan/miconazole nitrate microcapsules release about 49.5% of the drug while chitosan/clotrimazole microcapsules release more than 66.1% of the drug after 12 h under a pressure of 5 kg at pH 5.5, which is similar to the pH of human skin. The prepared drug-loaded microcapsules could be applied onto bandages or socks, and will continuously release antifungal drugs in a controlled manner under pressure.     

粒细胞-巨噬细胞集落刺激因子微球制剂的体外释放研究

目的：开发一种粒细胞-巨噬细胞集落刺激因子（GM—CSF）长效缓释微球剂型。方法：采用S／O／hO法制备了包裹粒细胞一巨噬细胞集落刺激因子多糖玻璃体颗粒的PLGA微球,考察了微球的表面形态、粒径分布等,并且运用ELISA方法考察了微球的体外释放效果。结果：本方法制备的粒细胞-巨噬细胞集落刺激因子微球光滑圆整,粒径分布均匀,体外可以缓释达32天,累积释放率接近90％。结论：本方法制备的粒细胞-巨噬细胞集落刺激因子微球能有效地保护蛋白活性,同时实现长效缓释的目标,是一种可行的蛋白缓释方案。     

桦褶孔菌漆酶固定化及其对染料的降解

采用壳聚糖交联法和海藻酸钠-壳聚糖包埋交联法固定化桦褶孔菌产生的漆酶,探讨最佳固定化条件,固定化漆酶的温度,pH稳定性及操作稳定性,并以两种固定化酶分别对4种染料进行了降解.结果表明:(1)壳聚糖交联法固定化漆酶的最佳条件为:壳聚糖2.5%,戊二醛7%,交联时间2h,固定化时间5h,给酶量1g壳聚糖小球:1mL酶液(1U/mL),固定化效率56%;(2)海藻酸钠-壳聚糖包埋交联法固定化漆酶的最佳条件为:海藻酸钠浓度4%,壳聚糖浓度0.7%,氯化钙浓度5%,戊二醛浓度0.6%,给酶量4mL 4%海藻酸钠:1mL酶液(1U/mL),固定化效率高达86%;(3)固定化的漆酶相比游离漆酶有更好的温度和pH稳定性;(4)比较两种固定化漆酶,海藻酸钠-壳聚糖包埋交联法固定化酶的温度及酸度稳定性要优于壳聚糖固定化酶,但可重复操作性要弱于后者,两者重复使用8次后的剩余酶活比率分别为71%及64%;(5)两种固定化酶对所选的4种不同结构的合成染料均有较好的降解效果,其中壳聚糖固定化酶对茜素红的降解效果及重复使用性极佳,重复降解40mg/L的茜素红10次,降解率仍保持在100%.