载环孢素A海藻酸钙-壳聚糖微球的制备及体外释放特性

目的:针对角膜移植术后免疫抑制治疗需求,制备眼部局部给药的小粒径载环孢素A缓释微球,并进行体外释放考察。方法:以海藻酸钠、壳聚糖为载体材料,采用静电液滴工艺,通过向制备体系添加表面活性剂,制备小粒径载环孢素A微球,设计正交试验优化处方工艺,扫描电镜观察微球表面形态,动态透析法考察微球的体外释放特性。结果:所制微球形态良好,粒径分布窄,平均粒径为(12.4±0.8)μm,包封率为(82.8±1.8)%,载药量为(50.1±1.2)%,体外释放行为用Higuchi方程拟合效果最好。结论:采用静电液滴工艺,通过减小制备体系的表面张力,制备了球形度优良、粒径小、包封率和载药量较高的载环孢素A的壳聚糖-海藻酸盐缓释微球,所得制剂的体外释药规律服从扩散机制。     

利福平丝素蛋白载药微球的制备及性能研究

目的通过测定利福平丝素蛋白微球的载药量、包封率及释放度,考察乳化转速、有机溶剂与丝素蛋白溶液比例,对微球的制备方法进行优化,筛选微球的最佳制备方法。方法采用乳化法制备利福平丝素蛋白微球,以不同转速、有机溶剂与丝素蛋白溶液不同比例分别制备利福平丝素蛋白微球,采用扫描电镜观察微球的形态,用紫外分光光度法测定微球的载药量、包封率及释放度,以形态、载药量、包封率及释放度为指标,筛选微球的最佳制备方法。在此基础上,采用最佳处方制备3批利福平丝素蛋白微球,对微球的形态、粒径、包封率、载药量和释放度进行考察。结果有机溶剂与丝素蛋白溶液体积比为4∶1、转速为200 r·min^-1时所得利福平丝素微球形态均匀,近似球形,载药量和包封率较高,所得载药微球有较好的缓释作用。以最佳处方制得微球载药量为66.1%±0.87%,包封率为87.80%±2.23%。结论有机溶剂与丝素蛋白溶液体积比为4∶1、转速为200 r·min^-1时载药量、包封率和释放度较好,故选择此处方为利福平丝素蛋白微球的最佳制备处方。     

美罗培南-海藻酸钙微球的制备与性能研究

目的 针对野战条件下战创伤感染缺乏长效抑菌杀菌药物现状,研制一种高效、安全、易用的新型外用抗感染复合材料.方法 应用天然高分子海藻酸钠、无水氯化钙为基质材料,强效抗生素美罗培南为包被药物,采用静电液滴法及冷冻干燥等制备工艺,制备美罗培南-海藻酸钙微球,并对其包封率、载药量、膨胀性及体外释药性进行检测,采用模拟药敏纸片法对其抑菌效果进行评估.结果 所制备的载药微球包封率为62.27%,载药量为19.40%,膨胀率可达80%;微球的释药模式符合缓释特征,可长效抑菌.结论 静电液滴法制备美罗培南-海藻酸钙微球具有可行性,微球性质稳定,释药模式理想、抑菌效果好.     

双氯芬酸钠/海藻酸钠微球的制备与体外释药行为考察

目的以海藻酸钠为载体材料,双氯芬酸钠为模型药物,制备载药微球并考察其性质及体外释放行为。方法本文采用海藻酸钠为药物载体,采用喷雾干燥法制备双氯芬酸钠/海藻酸钠微球。考察于双氯芬酸钠/海藻酸钠投料比对载药微球理化性质的影响。采用扫描电镜对所得到的微球进行形貌观察。同时考察其体外药物释放行为。结果所得到的载药微球形态呈不规则的扁平状,粒径分布较为均匀。通过控制投料比,可以得到不同粒径(5.64～9.58μm),载药量(5.76～18.43%)和包封率(35.45～43.92%)的载药微球。体外药物释放行为结果显示微球在含有0.5%氯化钙的PBS(pH=7.4)溶液的药物释放时间可以持续96h,具有一定的缓释效果。结论通过喷雾干燥法制备的双氯芬酸钠/海藻酸钠载药微球具有较高载药量和一定的药物缓释效果。     

球晶造粒法制备硝苯地平缓释微球

目的考察硝苯地平缓释微球的制备工艺及其体外释放度。方法以邻苯二甲酸羟丙甲纤维素酯(HP55)为载体材料,采用球晶造粒技术制备硝苯地平缓释微球。考察硝苯地平微球的粒径、形态、载药量、包封率及体外释放度。结果所得微球外观圆整度好,粒径分布在70~150μm,载药量为18.91%,包封率为94.95%。结论该法可用于硝苯地平缓释微球的制备。     

海洋多糖BTH缓释微球的制备及释放特性研究

目的 以海藻酸钠与壳聚糖为载体材料制备苯并[l,2,3]噻二唑-7-硫代羧酸甲酯(BTH)缓释微球并研究其释放特性。 方法 采用乳化-外源凝胶法制备BTH缓释微球,通过傅里叶变换红外光谱(FT-IR)验证BTH包封于微球当中,利用高效液相(HPLC)外标法测定微球的包封率、载药量以及不同pH溶液中的释放曲线。结果 BTH被均匀的分散在缓释微球当中,平均载药量为11.14%,平均包封率为81.52%,微球可持续释放12天,累计释放量达到61%。 结论 制备的BTH缓释微球形态圆整,表面光滑,成球性好,载药量与包封率较高,具有显著的缓释效果。     

水溶性药物聚丙交酯微球的研究

目的考察内相乙醇加入量及其他制备因素对聚丙交酯微球性质的影响。方法以水略溶性药物氟尿嘧啶和水溶性药物地基米松磷酸钠为模型药物，乳化／溶剂挥发法制备微球。维持其他制备条件不变，改变内相乙醇加入量、理论载药量、聚丙交酯浓度、溶剂挥发时间及聚丙交酯分子质量，考察微球载药量、包封率、粒径和释放的影响。结果随着内相乙醇加入量的增多，微球形成加快，微球的粒径减小，模型药物的载药量及包封率略有升高，但乙醇加入量太多时载药量及包封率均明显降低。内相聚丙交酯浓度越大，形成的微球粒径越大，载药量及包封率也愈大。理论载药量对微球粒径影响不大，地基米松磷酸钠的包封率随理论载药量的增加而减小，而氟尿嘧啶为理论载药量为15％时，包封率最大。溶剂挥发时间在0．5～3h，微球的性质无明显变化。分子质量愈小，微球的粒径愈小，载药量及包封率亦随之减小。结论内相中加入一定量乙醇可以提高药物的包封率，并减少有毒含氯溶剂的用量。     

ZnS-壳聚糖海藻酸钠包裹布洛芬纳米微球的制备和性能研究

目的以壳聚糖-海藻酸钠为基质材料,掺杂入纳米ZnS包裹非甾体抗炎药物布洛芬,制备缓、控释性能优异的载药纳米微球;为研发四代新剂型打下基础。方法利用复凝聚法,通过调整添加基质材料速度、反应温度、搅拌速度等,制备含ZnS的壳聚糖海藻酸钠布洛芬纳米微球,透射电镜观察纳米微球的形态,测试纳米微球的载药量与包封率,拟肠液条件下测试所致纳米微球的释放特性。结果含ZnS壳聚糖海藻酸钠布洛芬纳米载药微球的粒径约为80~100nm,载药量为40.2%药物包封率78.2%,ZnS粒径3nm。在水溶液、0.9%NaCl和磷酸盐缓冲液中的吸水膨胀程度小于不含ZnS的载药纳米微球;体外拟肠条件溶出表明含ZnS的载药纳米微球具有良好的缓控释性能,药代动力学特征为被动扩散。结论掺入了ZnS的壳聚糖海藻酸钠布洛芬纳米微球,形状圆整,包封率理想,具有良好的缓控释性能。     

盐酸维拉帕米缓释微球的制备及其质量评价

目的:制备维拉帕米缓释微球,并对其进行质量评价.方法:采用低温喷雾干燥法制备盐酸维拉帕米缓释微球,评价内容包括:微球的粒径及其分布、微球含药量、载药量和包封率、收率以及不同pH值下的释放速率.结果:成功制备了盐酸维拉帕米缓释微球,平均收率为28.97%,所得微球55%以上的粒径在3.0~5.0μm,载药量为26.11%,包封率为76.40%.结论:微球的体外累积释放度完全符合Higuchi方程,初步证实该微球的释放属于骨架溶蚀性过程.     

阿司匹林鼻粘膜给药淀粉微球的制备工艺及其质量控制

目的：对阿司匹林鼻粘膜给药淀粉微球的制备工艺进行考察，并评价其体外质量。方法：以羧甲基淀粉钠为原料，对苯二甲酰氯为交联剂，采用界面缩聚法制备空白再微球，用吸附载药法制备阿司匹林淀粉微球，并对其形态、载药量、包封率、体外释放度等进行了研究。结果：微球形态圆整，大小均匀，粒径在20－100μm，平均粒径为53．4μm，载药量16．65％，包封率92．5％，体外释药符合Weibull方程。结论：本微球制备工艺较简便，各种因素较易控制，重现性好，载药量与包封率均较高，符合鼻腔给药微球要求。     

Evaluation of furosemide-loaded alginate microspheres prepared by ionotropic external gelation technique

Alginate microspheres containing furosemide were prepared by the ionotropic external gelation technique using Ca2+, Al3+ and Ba2+ ions. The incorporation efficiency of the prepared microspheres ranged between 65% and 93%. The effect of sodium alginate concentration, cross-linking ions and drying conditions was evaluated with respect to entrapment efficiency, particle size, surface characteristics and in vitro release behavior. Infrared spectroscopic study confirmed the drug-polymer compatibility. Differential scanning calorimetric analysis revealed that the drug was molecularly dispersed in the alginate microsphere matrices. Scanning electron microscopic study of microspheres showed the rough surface due to higher concentration of drug molecules dispersed at molecular level in the alginate matrices. The mean particle size and entrapment efficiency were found to be varied by changing various formulation parameters. The in vitro release profile could be altered significantly by changing various formulation parameters to give a sustained release of drug from the microspheres. The kinetic modeling of the release data indicate that furosemide release from the alginate microspheres follow anomalous transport mechanism after an initial lag period when the drug release mechanism was found to be Fickian diffusion controlled.     

Influence of partially cross-linked alginate used in the production of alginate microspheres by emulsification

Spherical and discrete calcium alginate microspheres had been produced by the emulsification technique. The microencapsulation process was highly efficient, but drug release from microspheres was rapid. A more orderly chain arrangement of the polymeric chains would give rise to a stronger and less permeable matrix capable of sustaining drug release. Therefore, the potential of using partially cross-linked alginate in the production of microspheres by emulsification was explored. The size and roundness of the microspheres, its drug content and drug release property were determined. The more viscous alginate solutions when reacted with more calcium salt added resulted in larger microspheres produced. Microspheres made from partially cross-linked alginate exhibited lower drug content and higher T75% values in drug release studies. This was due to decreased flexibility of the polymer chains which were partially held together by calcium ions, reducing subsequent interaction with the calcium ions resulting in lower drug entrapment efficiency and a more permeable microsphere matrix.     

布比卡因缓释微球的制备及体外释药特性评价

目的研究布比卡因缓释微球制备方法并对其体外释药特性进行评价。方法采用紫外分光光度法测定布比卡因微球载药量、包封率;采用HPLC法测定微球体外释放;通过正交设计优选微球制备工艺;以乳酸羟基乙酸共聚物为载体,使用乳化溶剂挥发法制备布比卡因微球;用扫描电镜观察所得微球的粒径和形态;通过体外释药实验考察布比卡因乳酸羟基乙酸共聚物微球的缓释作用。结果微球载药量、包封率和体外释放的测定方法符合方法学要求;按照优选处方制备所得的微球为圆整球体,表面多孔,呈蜂窝状,粒径50~100μm之间的微球占80%;体外释放符合Ritger-Peppas方程,t1/2=242.05 h。结论乳化溶剂挥发法适用于布比卡因乳酸羟基乙酸共聚物微球的制备,所制得的微球形态圆整,在体外具有明显缓释作用。     

Design and characterization of chitosan-alginate microspheres for ocular delivery of azelastine

Abstract

The use of mucoadhesive biopolymers is one of the best approaches to prolong the drug residence inside the cul-de-sac, consequently increasing the bioavailability. Thus, the focus of this work was to develop mucoadhesive microspheres to overcome the limitations of ocular drug delivery. The chitosan-sodium alginate microspheres of azelastine hydrochloride were fabricated using modified ionotropic gelation technique. The particle size, zeta potential, entrapment efficiency and drug release kinetics were evaluated and characterized by SEM, FT-IR, DSC, in vitro mucoadhesion and in vivo study. The microspheres had average particle size in the range of 3.55 to 6.70?µm and zeta potential +24.55 to +49.56?mV. The fabricated microspheres possess maximum drug entrapment of 73.05% with 65% mucin binding efficiency and revealed a controlled release over the 8-h period following a non-Fickian diffusion. SEM showed that microspheres were distinct solid with irregular shape. FT-IR and DSC results concluded the drug entrapment into microspheres. In vivo studies on ocular rat model revealed that azelastine microspheres had better efficacy. Chitosan sodium alginate microspheres prepared were in particle size range suitable for ocular purpose. In vitro release and in vivo efficacy studies revealed that the microspheres were effective in prolonging the drug’s presence in cul de sac with improved therapeutic efficacy.     

多层海藻酸-壳聚糖聚电解质膜微球的制备与体外释放特性研究

目的：制备牛血清白蛋白-海藻酸-壳聚糖微球（BSA-ACM）,牛血清白蛋白-海藻酸-壳聚糖-海藻酸钠微球（BSA-ACAM）,牛血清白蛋白-海藻酸-壳聚糖-海藻酸-壳聚糖-海藻酸钠微球（BSA-ACACAM）。方法：以海藻酸钠和壳聚糖溶液为囊材,对BSA进行反复包裹,采用乳化-交联法制备BSA-ACM、BSA-ACAM、BSA-ACACAM;采用扫描电镜测定微球粒径,Micro-BCA试剂盒测定载药量,考察包封率和24h体外释药特性,并进行Higuchi方程拟合。结果：BSA-ACM、BSA-ACAM、BSA-ACACAM微球球形圆整,分散性好,平均粒径分别为（3.79±1.33）、（3.52±0.96）、（3.07±1.17）μm;载药量分别为（17.97±1.33）%、（16.95±0.46）%、（16.47±1.49）%;包封率分别为（65.78±4.98）%、（63.99±4.83）%、（55.00±1.50）%。微球体外释放速率与聚电解质膜包裹层数呈负相关,均符合Higuchi方程（r分别为0.9787、0.9869、0.9808）,24h内累积释放量分别为32.15%、25.59%、16.72%,无明显突释现象。结论：多层海藻酸-壳聚糖聚电解质膜微球能减少药物的突释,具有良好的缓释效果。     

Preparation and in vitro dissolution profile of zidovudine loaded microspheres made of Eudragit RS 100, RL 100 and their combinations

The objective of present investigation was to evaluate the entrapment efficiency of the anti-HIV drug, zidovudine, using two Eudragit polymers of different permeability characteristics and to study the effect of this entrapment on the drug release properties. In order to increase the entrapment efficiency optimum concentration of polymer solutions were prepared in acetone using magnesium stearate as droplet stabilizer. The morphology of the microspheres was evaluated using a scanning electron microscope, which showed a spherical shape with smooth surface. The mean sphere diameter was between 1000-3000 microm and the entrapment efficiencies ranged from 56.4-87.1%. Polymers were used separately and in combination to prepare different microspheres. The prepared microspheres were studied for drug release behavior in phosphate buffer at pH 7.4, because the Eudragit polymers are independent of the pH of the dissolution medium. The release profiles and entrapment efficiencies depended strongly on the structure of the polymers used as wall materials. The release rate of zidovudine from Eudragit RS 100 microspheres was much lower than that from Eudragit RL 100 microspheres. Evaluation of release data reveals that release of zidovudine from Eudragit RL 100 microspheres followed the Higuchi rule, whereas Eudragit RS 100 microspheres exhibited an initial burst release, a lag period for entry of surrounding dissolution medium into polymer matrix and finally, diffusion of drug through the wall material.     

Sodium alginate microspheres of metformin HCl: formulation and in vitro evaluation

Metformin microspheres with sodium alginate alone and in combination with gellan were prepared using an emulsion-cross linking method. The prepared microspheres were evaluated for their physico-chemical characteristics like particle size, morphology using SEM, incorporation efficiency, equilibrium water content (swelling) and in vitro drug release. The effect of various formulation variables like polymer concentration (sodium alginate; and proportion of gellan in microspheres prepared by a combination of sodium alginate and gellan), drug loading, crosslinking agent concentration and cross-linking time on the in vitro dissolution of the prepared microspheres were evaluated. The results showed that both the particle size and the incorporation efficiency were proportional to the polymer concentration. In case of microspheres containing both sodium alginate and gellan, the mean diameter and the incorporation efficiency were higher than the corresponding microspheres containing only alginate, both increasing with an increase in proportion of gellan. The prepared microspheres were found to be discrete and spherical in shape and were successful in sustaining the drug release for 8 hours. Incorporation of gellan caused a significant decrease in drug release. The release followed a biphasic profile, in all cases, characterized by an initial phase of moderate drug release followed by a phase of higher release. Further, the kinetic treatment of the dissolution data revealed the prevalence of matrix diffusion kinetics.     

利培酮长效注射微球的制备及体外释放的研究

目的：制备利培酮长效注射微球并考察其体外释放行为。方法：使用乳酸-羟基乙酸共聚物（PLGA）为材料,采用乳化-溶剂挥发法制备利培酮微球,观察微球的形态及粒径,测定微球的载药量和包封率,考察微球的体外释放情况。结果：利培酮微球表面圆整,粒径集中在40～80μm之间。微球的包封率较高,达到80％以上,以低分子量PLGA（50：50）制备的微球,体外突释很高达到40％以上;以高分子量PLGA（75：25）制备的微球,在高载药量时突释较小,可持续释放达3周以上。结论：以高分子量PLGA制备的高载药量的利培酮微球,体外突释较小可缓释达3周以上。     

Studies on microencapsulation of 5-fluorouracil with poly(ortho ester) polymers

Microencapsulation of 5-fluorouracil was successfully accomplished with poly(ortho ester) polymers by the emulsification-solvent evaporation method. While actual drug loading increased with increasing drug load (5-15% w/w), the entrapment efficiency remained essentially unaffected, under a given set of experimental conditions. Incorporation of sorbitan sesquioleate enhanced entrapment efficiency, decreased the volume-surface mean diameter of the poly(ortho ester) microspheres and provided controlled release of 5-fluorouracil. The volume of the aqueous phase was more important than the concentration of polyvinyl alcohol in it. The entrapment efficiency improved from 13 to 33% when the volume of the aqueous phase was increased from 20 to 80 ml. The volume of organic phase (methylene chloride) and the concentration of polymer in it played an important role. The use of smaller volumes of more concentrated polymer solution enhanced actual drug loading, entrapment efficiency and produced larger microspheres. The release studies conducted in 0.01 M phosphate buffer at 37+/-1.0 degrees C demonstrated that the release of 5-FU from the microspheres prepared with sorbitan sequioleate was nearly independent of the initial drug load with a mean zero-order rate constant of 0.0063% per hour. The data suggested that drug release was largely a diffusional process with contributions from dissolution and polymer degradation.     

A novel impinging aerosols method for production of propranolol hydrochloride-loaded alginate gel microspheres for oral delivery

Propranolol hydrochloride was directly encapsulated in alginate gel microspheres (40-50?μm in diameter) using a novel method involving impinging aerosols of CaCl(2) cross-linking solution and sodium alginate solution containing the drug. Microspheres formulated using 0.1?M CaCl(2) exhibited the highest drug loading (14%, w/w of dry microspheres) with 66.5% encapsulation efficiency. Less than 4% and 35% propranolol release occurred from hydrated and dried microspheres, respectively, in 2?h in simulated gastric fluid (SGF). The majority of the drug load (90%) was released in 5 and 7?h from hydrated and dried microspheres, respectively, in simulated intestinal fluid (SIF). Prior incubation of hydrated microspheres (cross-linked using 0.5?M CaCl(2)) in SGF prolonged the time of release in SIF to 10?h, which has implications for the design of protocols and correlation with in?vivo release behaviour. Restricted propranolol release in SGF and complete extraction in SIF demonstrate the potential of alginate gel microspheres for oral delivery of pharmaceuticals.