罗哌卡因-醋酸地塞米松PLGA微球的制备及体外释药特性研究

目的 制备罗哌卡因 醋酸地塞米松聚乳酸羟基乙酸共聚物（PLGA）微球（简称微球）并研究其体外释药特性。方法以PLGA为载体,采用W1/O/W2双重乳化 溶剂挥发法制备微球,研究实验过程中有机相PLGA浓度、外水相/有机相体积比、内水相体积、外水相聚乙烯醇（PVA）浓度几项因素变化对罗哌卡因 醋酸地塞米松PLGA微球粒径、表面形态﹑载药量﹑包封率和突释行为的影响。结果有机相PLGA浓度在制备微球的过程中是一个关键性因素。随着PLGA浓度增加,微球粒径增大,载药量﹑包封率明显提高,突释降低;外水相/有机相体积比增大,微球粒径增大, 载药量﹑包封率明显提高,微球表面更加光滑﹑微孔减少,突释降低;随着内水相体积增加使得微球表面的微孔明显增多,突释增加,载药量﹑包封率降低;当外水相PVA浓度由0.5%增加到2%,微球粒径变小,突释效应增加。通过优化条件制备的微球形状为球形,外观光滑圆整,粒径分布均匀,其中＞90%分布在20～70 μm。罗哌卡因载药量（7.48±0.33）%,包封率（70.97±2.36）%;醋酸地塞米松载药量（1.52±0.16）%,包封率（57.30±1.17）%。结论采用W1/O/W2双重乳化 溶剂挥发法成功制备罗哌卡因加醋酸地塞米松PLGA微球;以优化工艺制备的微球,在体外具有明显的缓释行为,释药曲线呈典型S形三阶段模式。     

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。     

GM-1缓释微球的制备及体外释药特性研究

目的:制备GM-1的乳酸/羟基乙酸共聚物(PLGA)微球,考察其一般性质和体外释药特性。方法:应用W/O/W型乳化溶剂干燥法制备GM-1的PLGA微球,测定微球粒径、载药量、包封率和体外释药曲线。结果:微球形态规则,粒径约为(18±8)μm,载药量约为4.9%,包封率约为61%,微球体外释药规律符合Higuichi方程Q=0.153t1/2+0.03705(r=0.9950)。结论:GM-1微球体外释药特性及其制备工艺良好,体外具有明显缓释作用。     

不同PLGA型号对奥曲肽微球的包封率和体外释放行为的影响

考察了不同型号聚乳酸-羟基乙酸共聚物(PLGA)作为水溶性药物奥曲肽微球载体对载药量、包封率和体外释放行为的影响.结果表明,PLGA中丙交酯含量降低,载药量和包封率降低,而突释量增大.PLGA型号相同时,黏度较大的PLGA微球载药量和包封率较高,突释量较小.采用PLGA与聚乳酸(PLA)混合材料制备的微球比单用PLGA材料微球的突释量小、载药量和包封率高、缓释效果好.     

阿司匹林缓释微球的制备及其体外释药性能研究

目的:制备阿司匹林缓释微球,并考察其体外释药性能。方法:采用改良的乳化溶剂挥发法,以聚乳酸-羟基乙酸共聚物(PLGA)为载体材料、载药量和包封率为指标,固定PLGA为100 mg正交设计试验优化阿司匹林缓释微球的阿司匹林用量、外水相体积、丙酮-二氯甲烷体积比和聚乙烯醇(PVA)浓度,对最优处方所制微球进行验证和体外释放度考察。倒置显微镜和电子显微镜下观察微球表面形态,激光粒度分析仪考察微球粒径。结果:PLGA为100 mg时的最优处方:阿司匹林用量为20 mg、外水相体积为150 ml、丙酮-二氯甲烷体积比为1∶1、PVA浓度为1 mg/100 ml;所制微球的平均粒径为139.95μm,电镜下微球表面光滑圆整,载药量为8.6%,包封率为33%,240 h体外累积释放度为85.56%。结论:成功制得具有明显缓释作用的阿司匹林缓释微球。     

处方和工艺参数对盐酸昂丹司琼微球体外释放度的影响

目的：考察处方工艺参数对微球体外释放度的影响.方法：采用O/O型乳化溶剂挥发法,以乳酸-羟基乙酸共聚物为载体,制备盐酸昂丹司琼（Ondansetron hydrochloride,OND）微球.采用紫外分光光度法测定微球的体外释放度.结果：选择对OND具有较好溶解能力的混合溶剂为内油相溶剂,可以降低突释;增加理论载药量,延缓正己烷加入的时间和减小粒径可以增加OND微球的释药速度.结论：通过对处方和工艺的调节可使OND微球的体外释药曲线符合Higuchi方程,2周的累积释放量在80%左右.     

超微粒制备系统制备利培酮长效注射微球

目的:制备利培酮长效注射微球并进行体外释药动力学考察。方法:选用聚乳酸-羟基乙酸共聚物[poly(D,L-lactic-co-glycolic acid),PLGA]为载体,采用新型超微粒制备系统制备利培酮PLGA微球。以转碟上聚合物析出量、丝状物的形成和微粒表面形态为考察指标单因素实验优化制备工艺参数及处方;观察微球表面形态,测定其粒径、包封率、考察其体外释药动力学。结果:20%和30%载药量的微球表面均光滑圆整,分散性好;其包封率分别为94.7%和93.94%,中值粒径分别为31.65和28.13μm;持续释药时间均可达16 d,释放数据用释放动力学方程拟合符合一级和Higuchi方程。20%载药量微球1 h释药率仅为4.2%,突释率低,且其释放速率和释放时间与市售利醅酮微球(恒德)快速释放期基本一致而无延滞期。结论:超微粒制备系统(UPPS)可单步骤制备长效微球,工艺稳定,简单可行,有望成为一种适合工业微球制备技术。UPPS制备的20%载药量微球可开发为释放2周的制剂,由于无释放延滞期,将比市售品更具临床优势。     

白益母草总生物碱聚乳酸-羟基乙酸共聚物微球的制备

目的:优化蒙药白益母草总生物碱的聚乳酸-羟基乙酸共聚物(PLGA)微球的处方工艺,制备微球并对其进行质量考察。方法:采用复乳-液中干燥法制备白益母草总生物碱PLGA微球,以处方中PLGA质量浓度、聚乙烯醇(PVA)浓度及内水相/油相体积比为因素,以微球的载药量、包封率、收率的综合评分为指标,采用L9(34)正交试验优化制备微球的处方工艺,并考察微球形态、粒径及体外释药情况。结果:最优工艺为PLGA 200 mg/ml、PVA 2%、内水相/油相的体积比为1∶5;验证试验中平均包封率为(83.2±2.4)%,平均载药量为(4.16±0.17)%,平均收率为(86.7±3.6)%,综合评分结果为(95.7±4.4)%,RSD均小于5.0%(n=3);制备的微球形态圆整,表面光滑,粒径分布均匀,平均粒径为(22.3±2.4)μm;微球24 h体外累积释放度为(82.3±3.5)%,符合一级释放模型(r=0.972 4)。结论:优选工艺稳定;制备的微球具有良好的缓释性能,质量符合要求。     

聚乳酸-羟基乙酸共聚物载药微球性质及缓释行为的影响因素

聚乳酸-羟基乙酸共聚物（PLGA）包裹药物制成缓释微球是药物缓释方向的研究热点,PLGA微球作为载体,具有良好的生物相容性和降解性,但载药微球的性质和释药性能易受很多因素影响,如PLGA相对分子质量,LA/GA比例,微球制备工艺等,这些因素对载药体系在生物医学领域的应用造成一定限制。结合国内外相关文献,本文综述了PLGA微球在制备及释药过程中,影响其理化性质和重要性能的因素,包括载药量,包封率,突释问题等方面,为PLGA微球进一步研究和优化提供思路。     

微球中聚乳酸羟基乙酸共聚物浓度与微球结构、释药、降解的关系研究

目的:研究微球中聚乳酸羟基乙酸共聚物(PLGA)浓度与微球结构、释药、降解的关系。方法:以牛血清白蛋白(BSA)为药物,采用复乳法制备PLGA浓度分别为10%、15%、20%的BSA-PLGA微球,以包封率、载药量、粒径为指标考察PLGA浓度对3种微球性质的影响;采用扫描电子显微镜观察3种微球和降解40 d内的外观和内部形态;使用荧光蛋白-异硫氰酸荧光素牛血清白蛋白代替BSA作为模型药物制备PLGA微球,并采用激光共聚焦显微镜观察荧光蛋白在微球骨架内的分布情况;采用BCA法考察3种微球的体外释药情况;采用压汞仪考察降解28 d内20%PLGA所制微球的孔径、孔隙率、截面孔隙率的变化;采用凝胶渗透色谱法检测10%、20%PLGA所制微球降解28 d内分子质量及其降解模型拟合。结果:与10%、15%PLGA所制微球比较,20%PLGA所制微球的包封率[(81.96±1.84)%]和粒径[(139.50±0.21)μm]最大,载药量[(7.28±0.45)%]最低,截面孔隙率[(32.35±1.98)%]和孔径[(12.43±0.14)μm]最小,释药突释率最低,40 d内的释放速率相对较慢,降解后截面孔隙率最大,降解均遵循假一级模式(r2=0.065 3)。结论:在考察范围内,随着PLGA浓度的增加,微球的结构更致密,释药更平稳,降解更易形成中空结构。     

Microspheres made by w/o/o emulsion method with reduced initial burst for long-term delivery of endostar, a novel recombinant human endostatin

The purpose of this work is to design biodegradable Poly(lactide-co-glycolide) (PLGA) microspheres with low initial burst for sustained delivery of Endostar (a novel recombinant human endostatin) and investigate effects of PLGA molecular weight and composition on the release behavior of Endostar microspheres. Endostar microspheres were prepared by using novel w/o/o multiple emulsification-evaporation technique. Effects of polymer molecular weight and copolymer composition on particle properties and release behavior (in vitro and in vivo) have been reported. Drug release in vitro decreased with increase in molecular weight and lactide content of PLGA. Zero order release and low initial burst were obtained with all microsphere formulations. The in vivo performance of Endostar microspheres were also found to be dependent on the polymer molecular weight and copolymer composition. Together, these results suggest that the initial burst release can be reduced by w/o/o emulsion method and the release of Endostar can be changed significantly by varying the polymer molecular weight and copolymer composition.     

盐酸倍他洛尔蒙脱石微球的制备及其体外释放性能的研究

目的制备可满足缓释要求的镶嵌蒙脱石的离子交换缓释微球。方法采用S/O1/O2/O3复乳-溶剂挥发法制备微球,考察处方因素包括复乳相体积比例、药物质量浓度、膜材用量和乳化剂质量分数对微球制备的影响。以微球体外释放为考察指标,优化微球处方。结果研究所得到的微球最佳处方为大豆油∶药物=6∶1,药物∶膜材=1∶5,乳化剂质量分数为0.5%²%。除乳化剂外,其他因素对微球体外释放均有较大影响。所制备微球的体外释放可以达到10h,基本无突释现象。进行形态观察发现,微球较为圆整,粒径比较均匀。结论采用优化处方以复乳-溶剂挥发法所制备盐酸倍他洛尔蒙脱石微球体外具有缓释性能。     

胸腺肽α1缓释注射微球的研究

制备胸腺肽α₁(Tα₁)的长效注射微球，并对微球的体外释放特性、体外活性及药效学进行考察。采用复乳法(W/O/W)制备了载Tα₁聚乳酸-羟基乙酸嵌段共聚物(PLGA)的微球；考察微球的粒径大小、外观及包封率等理化特性；以HPLC法测定微球的体外释放速率；采用CCK-8法评价微球制备工艺和体外释放过程中Tα₁的生物学活性；体内药效学研究中采用流式细胞仪检测免疫抑制模型大鼠给予Tα₁微球后所产生的CD₄⁺，CD₈⁺因子的量，根据CD₄⁺/CD₈⁺的比值变化评价体内药效。微球球形圆整，分散性好，两个优选处方(外水相中加入5%氯化钠和10%葡萄糖)的微球包封率分别为87.8%和90.2%；Tα₁微球1个月的体外累积释放可达90%以上。使用含10%葡萄糖的PVA溶液作为外水相，较好地保持了制备工艺过程中的Tα₁生物学活性，在体外释放过程中Tα₁的生物学活性略有下降；Tα₁微球可显著提高免疫抑制模型小鼠的免疫力。用可生物降解的聚合物PLGA作为载体材料，可以将Tα₁制备成缓释1个月的注射微球。     

胰高血糖素样肽-1长效注射微球的研究

目的制备载胰高血糖素样肽-1(GLP-1)的长效注射微球，并对其体外释放特性及药效学进行考察。方法采用复乳法(W/O/W)制备载GLP-1聚乳酸-羟基乙酸嵌段共聚物(PLGA)的微球；考察微球的粒径大小、外观及包封率等理化特性；以HPLC法测定微球的体外释放速率；在体动物法评价微球制备工艺和体外释放过程中GLP-1的生物学活性。在糖尿病模型小鼠体内考察了微球的降血糖作用。结果微球球形圆整，分散性好，包封率在80%以上；GLP-1微球1个月的体外累积释放可达85%，其释放行为符合近似零级释放模式；使用明胶溶液作为内水相，较好地保持了制备工艺过程中的GLP-1生物学活性，在体外释放过程中GLP-1的生物学活性略有下降；GLP-1微球可显著降低糖尿病模型小鼠的血糖水平，降糖作用可维持1个月。结论用可生物降解的聚合物PLGA作为载体材料，可以将GLP-1制备成缓释1个月的注射微球。     

Microfluidic-based fabrication and characterization of drug-loaded PLGA magnetic microspheres with tunable shell thickness

To overcome the shortcoming of conventional transarterial chemoembolization (cTACE) like high systemic release, a novel droplet-based flow-focusing microfluidic device was fabricated and the biocompatible poly(lactic-co-glycolic acid) (PLGA) magnetic drug-eluting beads transarterial chemoembolization (TACE) microspheres with tunable size and shell thickness were prepared via this device. Paclitaxel, as a model active, was loaded through O/O/W emulsion method with high efficiency. The size and the shell thickness vary when adjusting the flow velocity and/or solution concentration, which caters for different clinical requirements to have different drug loading and release behavior. Under the designed experimental conditions, the average diameter of the microspheres is 60 ± 2 μm and the drug loading efficiency has reached 6%. The drug release behavior of the microspheres shows the combination of delayed release and smoothly sustained release profiles and the release kinetics differ within different shell thickness. The microspheres also own the potential of magnetic resonance imaging (MRI) visuality because of the loaded magnetic nanoparticles. The microsphere preparation method and device we proposed are simple, feasible, and effective, which have a good application prospect.     

PLGA微球的制备及其用于脉冲给药的初步研究

目的：制备聚乳酸-羟基乙酸共聚物（PLGA）微球,并考察其用于脉冲式释药系统的可行性。方法：以牛血清白蛋白（BSA）为模型药物,用S/O/W（Solid-in-oil-in-water）法和S/O/O（Solid-in-oil-in-oil）法制备PLGA（75：25）和PLGA（50：50）微球,比较2种方法制备的微球的表面形态、包封率及载药量等,并考察2种微球的体外释放行为。结果：S/O/W法和S/O/O法制备的微球均圆整、无粘连、形态良好,但S/O/W法制备的微球表面较为平整,而S/O/O法表面均匀分布有较大的凹陷。S/O/W法制备的PLGA（75：25）和PLGA（50：50）微球包封率分别为（60.15±5.95）%、（49.50±3.69）%,载药量分别为（2.56±0.25）%、（2.10±0.16）%,10h内药物释放均为10%左右,而后随着聚合物的降解药物的释放量突然增加;S/O/O法所制微球包封率分别为（84.36±1.11）%、（77.94±1.42）%,载药量分别为（3.58±0.05）%、（3.31±0.06）%,24h内药物释放均可达50%左右,而后呈现较为平稳的释放行为。S/O/O法制备的微球包封率及载药量均较S/O/W法高;S/O/W法制备的PLGA微球药物释放呈现一定的脉冲行为,其中PLGA（75：25）微球体外释放行为受微球粒径的影响较大。结论：S/O/W法制备的PLGA微球具有一定的脉冲式释药效果,微球的粒径最好控制在120μm以下。     

蛋白质/多肽药物聚乳酸/乳酸-羟基乙酸共聚物微球研究进展

缓释微粒给药系统是蛋白质/多肽药物传输系统的一个重要研究方向，聚乳酸和乳酸-羟基乙酸共聚物是制备缓释微球最常用的载体材料。蛋白质/多肽药物聚乳酸/乳酸-羟基乙酸共聚物微球常用的制备方法包括溶剂萃取/挥发法(复乳法)、相分离法和喷雾干燥法。本文总结了微球制备中面临的难点如蛋白质/多肽药物稳定性、包封率、药物突释和药物吸附等问题，并综述了保持药物结构稳定性和生物活性、提高包封率、改善药物释放曲线等微球制备方法和进展。     

Heparin Immobilized Porous PLGA Microspheres for Angiogenic Growth Factor Delivery

Purpose Heparin immobilized porous poly(d,l-lactic-co-glycolic acid) (PLGA) microspheres were prepared for sustained release of basic fibroblast growth factor (bFGF) to induce angiogenesis.Materials and Methods Porous PLGA microspheres having primary amine groups on the surface were prepared using an oil-in-water (O/W) single emulsion method using Pluronic F-127 as an extractable porogen. Heparin was surface immobilized via covalent conjugation. bFGF was loaded into the heparin functionalized (PLGA-heparin) microspheres by a simple dipping method. The bFGF loaded PLGA-heparin microspheres were tested for in vitro release and in vivo angiogenic activity.Results PLGA microspheres with an open-porous structure were formed. The amount of conjugated amine group onto the microspheres was 1.93 ± 0.01 nmol/mg-microspheres, while the amount of heparin was 95.8 pmol/mg-microspheres. PLGA-heparin microspheres released out bFGF in a more sustained manner with a smaller extent of initial burst than PLGA microspheres, indicating that surface immobilized heparin controlled the release rate of bFGF. Subcutaneous implantation of bFGF loaded PLGA-heparin microspheres in mice significantly induced the formation of new vascular microvessels.Conclusions PLGA microspheres with an open porous structure allowed significant amount of heparin immobilization and bFGF loading. bFGF loaded PLGA-HP microspheres showed sustained release profiles of bFGF in vitro, demonstrating reversible and specific binding of bFGF to immobilized heparin. They also induced local angiogenesis in vivo in an animal model.     

Doxorubicin loading and eluting characteristics of bioresorbable hydrogel microspheres: in vitro study

Non-bioresorbable drug eluting microspheres are being increasingly used for the treatment of unresectable liver tumors, whereas bioresorbable microspheres have not received much attention. In this study, bioresorbable microspheres prepared from chitosan and carboxymethyl cellulose were loaded with doxorubicin (Doxo) via ion-exchange interactions with carboxylic groups in the microspheres. With a 25-40% decrease in the microsphere size depending on their size ranges, the microspheres could load a maximum of 0.3-0.7 mg Doxo/mg dry spheres. As confirmed by confocal microscopy, Doxo was mainly concentrated in the outer 20±5 μm surface layer of the microspheres. The loaded microspheres were stable in aqueous dispersions without aggregation for a prolonged period of time but degradable in a lysozyme solution. Furthermore, the loaded microspheres exhibited a noticeable pH-sensitive behavior with accelerated release of Doxo in acidic environment due to the protonation of carboxylic groups in the microspheres. Compared to commercial non-resorbable drug eluting beads, the loaded bioresorbable microspheres showed a sustained release manner in phosphate buffered saline (PBS). The release data were fitted to an empirical relationship, which reveals a non-Fickian transport mechanism (n=0.55-0.59). These results demonstrate that the bioresorbable microspheres are promising as attractive carriers for Doxo.     

长春西汀聚乳酸-聚乙醇酸缓释微球的研制

目的:制备长春西汀聚乳酸-聚乙醇酸(PLGA)缓释微球,并研究其药剂学性质。方法:采用改良O/W乳化-溶剂挥发法制备微球,以PLGA浓度、理论载药量、有机相与分散介质的比例和分散介质中明胶的浓度为4因素,每个因素选定3个水平,按L9(34)的正交设计方案,以载药量、包封率和粒径分布为指标,优化处方。用扫描电镜观察微球的形态,用光学显微镜观察并计算微球的粒径分布,用差示扫描量热(DSC)法研究药物在载体中的分散状态,用紫外分光光度法检测微球中长春西汀含量并计算载药量和包封率,用动态透析释药法进行微球的体外释放研究。结果:最佳处方为PLGA浓度16%,理论载药量20%,有机相与分散介质的比例1:10,分散介质中明胶的浓度1%;制备的长春西汀PLGA缓释微球的形态圆整、光滑,粒径分布均匀,平均粒径为(10.0±0.18)μm(n=500),DSC法分析药物确已被包裹于微球中,载药量为(18.46±0.26)%,包封率为(91.30±0.98)%(n=3),24h累积释药率约为18%。结论:长春西汀PLGA缓释微球制备工艺稳定,质量符合药剂学要求,缓释性好。