SPG膜乳化法制备槲皮素缓释微球的工艺优化与表征及体外释放研究

目的 以槲皮素作为模型药物,制备聚乳酸-羟基乙酸共聚物(PLGA)缓释微球,考察其粒径及其分布、形态、包封率、载药量和体外释药性质.方法 采用SPG膜乳化法制备微球,单因素法初步优化制备处方;粒径分析仪检测微球的粒径及其分布;光学显微镜观察微球形态;通过紫外分光光度法测定微球的包封率和载药量;利用直接释药法和超速离心法...     

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。     

GM-l PLGA微球的制备及其体外释药性质研究

目的制备GM l PLGA微球，考察其一般性质和体外释药特性。方法应用W/O/W乳化溶剂干燥法制备GM l 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+0.037 05(r=0.995)。结论GM l PLGA微球的制备工艺良好，体外释药呈明显的缓释作用。     

雌二醇生物可降解缓释微球的制备四氢呋喃的加入对微球性质的影响

目的　在本实验中 ,以生物可降解和生物相容性良好的聚乳酸 (PLA)或乳酸 -乙醇酸共聚物 (PLGA)为载体材料制备含有雌二醇药物的缓释微球 ,考察在制备过程中水溶性更强的四氢呋喃的加入对微球性质的影响。方法　以乙酸乙酯和四氢呋喃为有机溶剂、采用乳化 -溶剂萃取法制备含药微球 ,分别从成球性、粒径、包封率和体外释药等方面 ,进行制备工艺研究以及微球相关性质的研究。结果　在乙酸乙酯中加入四氢呋喃 ,使包封率降低 ,但在乙酸乙酯体积比大于 5 0 %时 ,增加四氢呋喃的用量对包封率无明显影响。相同条件下 ,在考察范围内 ,粒径随四氢呋喃用量比例的增大而增大 ,而载体的性质和微球含药量是影响微球释药的主要因素。结论　尽管在制备过程中的油相中加入了水溶性更强的四氢呋喃 ,但是通过控制制备工艺和条件 ,仍然可以得到球形态好、有适当粒径分布范围、载药量高并且突释程度小的雌二醇生物可降解缓释微球     

吸附和包埋法制备洛美沙星淀粉微球及其体外释放比较研究

目的制备盐酸洛美沙星淀粉微球,并对其体外释药模式进行研究。方法以盐酸洛美沙星为模型药物,采用吸附载药法和包埋载药法制备了载药淀粉微球,通过测定微球载药量、包封率和在不同的释放介质中的体外释放情况,对上述2种方法制备的载药微球进行质量评价。结果吸附法制备的载药微球的平均载药量为14.54μg·mg^-1,药物包封率为39.72%;而包埋载药法制备的淀粉微球的平均载药量为19.32μg·mg^-1,药物包封率为48.95%。体外释药特性研究表明它们具有缓释特性,其中包埋载药法制备的淀粉微球比吸附载药法制备的淀粉微球有更好的缓释能力,在不同的释放介质中释药曲线也有所不同,在模拟胃液中累计释药量只能得到70%;而在模拟肠液中累计释药量能达到80%以上。结论吸附载药法和包埋载药法制备的载药淀粉微球都具有缓释作用,但后者体外释药具有更明显的缓释效果。     

关节腔注射用氟比洛芬PLGA缓释微球的制备及体外释放特性研究

目的制备关节腔注射用氟比洛芬(FP)缓释微球并研究其体外释药特性。方法以聚乳酸-羟基乙酸共聚物(PLGA)为材料,采用乳化-溶剂挥发法制备微球;正交设计法优化微球的制备工艺;采用透析法研究体外释药特性,UV法测定FP的含量。结果正交试验表明,PLGA的浓度是影响微球包封率的非常显著性因素。微球粒径范围为1.5~24.3μm,平均粒径为10.6μm,载药量为7.1%(W/W),包封率为92.7%,体外释药符合Higuchi方程,释放时间显著延长。结论本法制备的FP微球粒径大小适宜,具有明显的缓释作用,符合关节腔注射给药设计要求。     

PLGA包埋硫酸庆大霉素缓释微球的制备及体外释放行为

以生物可降解乙交酯和丙交酯的无规共聚物(PLGA)为载体,将硫酸庆大霉素分散在PLGA的有机溶液中,采用复乳溶剂挥发法制备了药物缓释微球。研究搅拌速度、PLGA浓度、乳化剂浓度和硫酸庆大霉素溶液体积对微球粒径的影响,观察微球的表面形貌,测定微球粒径、粒径分布和包封率,评价载药微球的体外释放行为。结果表明,采用甲基纤维素为乳化剂制备的微球形态完整,中粒径为(130±30)μm,微球中硫酸庆大霉素的包封率均在36%以上,平均42%,最高达56%。硫酸庆大霉素/PLGA微球具有显著的药物缓释作用,体外释放30d的累积释药率达80%以上。     

吸附和包埋法制备洛美沙星淀粉微球及其体外释放比较研究

目的 制备盐酸洛美沙星淀粉微球,并对其体外释药模式进行研究。方法 以盐酸洛美沙星为模型药物,采用吸附载药法和包埋载药法制备了载药淀粉微球,通过测定微球载药量、包封率和在不同的释放介质中的体外释放情况,对上述2种方法制备的载药微球进行质量评价。结果 吸附法制备的载药微球的平均载药量为14.54 µg·mg^-1,药物包封率为39.72%;而包埋载药法制备的淀粉微球的平均载药量为19.32 µg·mg^-1,药物包封率为48.95%。体外释药特性研究表明它们具有缓释特性,其中包埋载药法制备的淀粉微球比吸附载药法制备的淀粉微球有更好的缓释能力,在不同的释放介质中释药曲线也有所不同,在模拟胃液中累计释药量只能得到70%;而在模拟肠液中累计释药量能达到80%以上。结论 吸附载药法和包埋载药法制备的载药淀粉微球都具有缓释作用,但后者体外释药具有更明显的缓释效果。     

丹皮酚聚乳酸羟基乙酸微球的制备及体外释药考察

目的:制备丹皮酚聚乳酸羟基乙酸(PLGA)微球,考察其体外释药过程。方法:以丹皮酚为芯材,以PLGA为载体,采用乳化溶剂挥发法制备丹皮酚PLGA微球;以聚乙烯醇质量分数、PLGA质量浓度、药物与PLGA质量比及水油相体积比为考察因素,以包封率和载药量的综合评分为评价指标,采用正交试验优选制备工艺;扫描电镜和光学显微镜观察微球的外观和粒径,并测定其体外释药过程。结果:优选的工艺为聚乙烯醇质量分数0.9%、PLGA质量浓度60g/L、药物与PLGA质量比1∶3、水油相体积比1∶10。制得的微球球型规则,表面平滑,平均粒径为(31.75±0.13)μm。微球的载药量为(21.16±0.51)%,包封率为(66.91±1.62)%,8h体外累积释药量为37%。结论:所选工艺可用于制备丹皮酚PLGA微球,可为缓释药物传递系统的开发提供参考。     

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。     

乳酸/羟基乙酸共聚物的分子量及其单体组成比例对利培酮微球性质的影响

目的:制备利培酮-乳酸(LA)/羟基乙酸(GA)共聚物(R-PLGA)缓释微球,并对微球的性质及释放效果进行评价。方法:采用单乳溶剂蒸发法制备R-PLGA缓释微球;对微球的粒径分布、载药量、包封率、突释、体外释放等指标进行测定,考察PL-GA不同分子量和LA/GA不同单体组成比例对微球性质的影响。结果:所制微球外观圆整,分散良好。PLGA的单体组成比例以及分子量对微球性质尤其是释放速度有明显的影响。结论:可通过调节PLGA的分子量和LA/GA单体组成比例改变微球性质,以达到控制微球释放速率等预期目的。     

Controlled release of dexamethasone from PLGA microspheres embedded within polyacid-containing PVA hydrogels

The development of zero-order release systems capable of delivering drug(s) over extended periods of time is deemed necessary for a variety of biomedical applications. We hereby describe a simple, yet versatile, delivery platform based on physically cross-linked poly(vinyl alcohol) (PVA) microgels (cross-linked via repetitive freeze/thaw cycling) containing entrapped dexamethasone-loaded poly(lactic-co-glycolic acid) (PLGA) microspheres for controlled delivery over a 1-month period. The incorporation of polyacids, such as humic acids, Nafion, and poly(acrylic acid), was found to be crucial for attaining approximately zero-order release kinetics, releasing 60% to 75% of dexamethasone within 1 month. Microspheres alone entrapped in the PVA hydrogel resulted in negligible drug release during the 1-month period of investigation. On the basis of a comprehensive evaluation of the structure-property relationships of these hydrogel/microsphere composites, in conjunction with their in vitro release performance, it was concluded that these polyacids segregate on the PLGA microsphere surfaces and thereby result in localized acidity. These surface-associated polyacids appear to cause acid-assisted hydrolysis to occur from the surface inwards. Such systems show potential for a variety of localized controlled drug delivery applications such as coatings for implantable devices.     

氟维司群PLA-block-mPEG微球在大鼠体内的药动学研究

分别以嵌段共聚物(聚乳酸-单甲氧基聚乙二醇,分子量比为40 000:2 000)和非嵌段共聚物(聚乳酸-聚羟乙酸,分子量均为40 000,摩尔比分别为75:25、50:50)作为载体材料,采用乳化-液中干燥法制备包载氟维司群的微球.大鼠单剂量(50 mg/kg)皮下注射3种氟维司群微球,采用LC-MS/MS法测定血药浓度,计算药动学参数.结果表明,使用嵌段共聚物制备的微球,药-时曲线较平稳,释放效果较好.     

胰高血糖素样肽-2/聚乳酸-羟基乙酸微球的制备及其体外释药性质研究

目的:制备胰高血糖素样肽-2(GLP-2)/聚乳酸-羟基乙酸(PLGA)微球,并对其体外释药特性进行研究。方法:通过L(93)4正交试验设计优选微球最佳制备工艺条件,采用复乳-溶剂挥发法制备GLP-2/PLGA微球,并对制备工艺的重现性、所制微球的性质及体外释药性能进行考察。结果:优选的GLP-2/PLGA微球的最佳制备工艺稳定、重现性好;微球形态圆整,粒度分布均匀,平均粒径为14.49μm,载药量为13.48%,包封率为36.97%,微球在6 d内释药缓慢而均匀。结论:建立的制备工艺条件稳定、可行,所制微球初步达到了预期的试验目的。     

A novel approach to stabilization of protein drugs in poly(lactic-co-glycolic acid) microspheres using agarose hydrogel

A novel approach has been taken to stabilize protein drugs in poly(lactic-co-glycolic acid) (PLGA) microspheres. This approach creates a new protein drug delivery system, which is based on the combination of agarose hydrogel particles and PLGA microspheres. This combination produces a heterogeneously structured polymeric composite. The protein drug molecules are encapsulated in the agarose hydrogel particles and the drug-containing agarose hydrogel particles are further dispersed in the PLGA microspheres. One PLGA microsphere may contain many agarose hydrogel particles to form a PLGA–agarose composite microsphere. The PLGA–agarose composite microspheres have spherical shape and a smooth surface. They possess a normal or Gaussian size distribution and an average diameter of 150 μm. The PLGA–agarose composite microspheres have higher protein loading efficiency than that of the conventional PLGA microspheres. The hydration of the PLGA–agarose composite microsphere matrix is faster than that of the conventional PLGA microspheres. Protein drugs can be slowly released from the PLGA–agarose composite microspheres. The agarose hydrogel particles can stabilize protein drugs in the PLGA matrix, which is the major advantage of this novel protein drug delivery system over the conventional PLGA microspheres.     

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。     

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。     

Enhancing Alendronate Release from a Novel PLGA/Hydroxyapatite Microspheric System for Bone Repairing Applications

Purpose  The goal of this study was to exploit the multifunction of PLGA based microsphere as efficient alendronate delivery and also as potential injectable cell carrier for bone-repairing therapeutics. Materials and Methods  Novel poly (lactic-co-glycolic acid) (PLGA)-hybridizing -hydroxyapatite (HA) microspheres loaded with bisphosphonate-based osteoporosis preventing drugs, alendronate (AL), are prepared with solid/oil/water (s/o/w) or water/oil/water (w/o/w) technique. Macrophage resistance was evaluated by MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, DNA assay and Live/dead staining, and osteoblast proliferation and maturation was assessed by MTT assay, Alkaline phosphatase (ALP) activity assay and Real time-PCR. Results  In such fabricated AL laden PLGA/HA microspheric composites (abbreviated “PLGA/HA-AL”), the introduction of HA component has been proven capable of largely enhancing drug encapsulation efficiency especially when the single emulsion protocol is adopted. The in-vitro drug (AL) releasing profile of PLGA/HA-AL system was plotted basing over 30 days’ data collection. It indicates a sustained releasing tendency despite a minimal burst at the very beginning. The in-vitro bone-repairing efficacy of PLGA/HA-AL system was first tested with macrophages that are identified as precursors of osteoclasts and potentially responsible for osteoporosis. The results indicated that the AL release significantly inhibited the growth of macrophages. Additionally, as a central executor for osteogenesis, osteoblasts were also treated with PLGA/HA-AL system in vitro. The outcomes confirmed that this controlled release system functions to improve osteoblast proliferation and also enables upregulation of a key osteogenic enzyme ALP. Conclusions  By pre-resisting osteoclastic commitment and promoting osteoblastic development in vitro, this newly designed PLGA/HA-AL controlled release system is promoting for bone-repairing therapeutics.     

Effect of Polymer Blending on the Release of Ganciclovir from PLGA Microspheres

Purpose The aim of the study is to investigate the effect of polymer blending on entrapment and release of ganciclovir (GCV) from poly(d,l-lactide-co-glycolide) (PLGA) microspheres using a set of empirical equations. Methods Two grades of PLGA, PLGA 7525 [d,l-lactide:glycolide(75:25), MW 90,000–126,000 Da] and Resomer RG 502H [d,l-lactide:glycolide(50:50), MW 8000 Da], were employed in the preparation of PLGA microspheres. Five sets of microsphere batches were prepared with two pure polymers and their 1:3, 1:1, and 3:1 blends. Drug entrapment, surface morphology, particle size analysis, drug release, and differential scanning calorimetric studies were performed. In vitro drug-release data were fitted to a set of empirical sigmoidal equations by nonlinear regression analysis that could effectively predict various parameters that characterize both diffusion and degradation cum diffusion-controlled release phases of GCV. Results Entrapment efficiencies of GCV ranged from 47 to 73%. Higher amounts of GCV were entrapped in polymer blend microspheres relative to individual polymers. Triphasic GCV release profiles were observed, which consisted of both diffusion and degradation cum diffusion-controlled phases. In vitro GCV release was shortest for Resomer RG 502H microsphere (10 days) and longest for PLGA 7525 microspheres (90 days). Upon blending, the duration of release gradually decreased as the content of Resomer RG 502H in the matrix was raised. Equations effectively estimated the drug-release rate constants during both the phases with high R² values (>0.990). GCV release was slower from the blend microsphere during the initial diffusion phase. Majority of entrapped drug (70–95%) was released during the matrix degradation cum diffusion phase. Conclusions Drug entrapment and release parameters estimated by the equations indicate more efficient matrix packing between PLGA 7525 and Resomer RG 502H in polymer-blended microspheres. The overall duration of drug release diminishes with rising content of Resomer RG 502H in the matrix. Differential scanning calorimetry studies indicate stronger binding between the polymers in the PLGA 7525/Resomer RG 502H∷ 3:1 blend. Polymer blending can effectively alter drug-release rates of controlled delivery systems in the absence of any additives.     

Biodegradable poly(D,L-lactide-co-glycolide) (PLGA) microspheres for sustained release of risperidone: Zero-order release formulation

The preparation and investigation of sustained-release risperidone-encapsulated microspheres using erodible poly(D, L-lactide-co-glycolide) (PLGA) of lower molecular weight were performed and compared to that of commercial Risperdal Consta^? for the treatment of schizophrenia. The research included screening and optimizing of suitable commercial polymers of lower molecular weight PLGA50/50 or the blends of these PLGA polymers to prepare microspheres with zero-order release kinetics properties. Solvent evaporation method was applied here while studies of the risperidone loaded microsphere were carried out on its drug encapsulation capacity, morphology, particle size, as well as in vitro release profiles. Results showed that microspheres prepared using 50504A PLGA or blends of 5050-type PLGAs exerted spherical and smooth morphology, with a higher encapsulation efficiency and nearly zero-order release kinetics. These optimized microspheres showed great potential for a better depot preparation than the marketed Risperdal Consta^?, which could further improve the patient compliance.