叶酸靶向介孔二氧化硅纳米粒的制备及其缓释研究

纳米药物缓释系统由于具有抗药性小、毒副作用低、治疗效果好等优点,得到研究者们的广泛关注。首先以双键修饰的介孔二氧化硅纳米粒为基质,叶酸和丙烯酰基-β-环糊精单体(β-CD-A)为功能单体,N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,通过自由基聚合法制备了叶酸靶向药物载体MSNs@P(CD-co-FA)。然后采用浸渍法对姜黄素进行载药吸附。结果表明：MSNs@P(CD-co-FA)的最佳载药浓度为300mg/L,对姜黄素的平衡吸附量为81.7mg/g,最佳载药时间为10h。体外释药结果显示,MSNs@P(CD-co-FA)在24h时累计释放率为11.24%。     

氧氟沙星PLGA微囊的制备、表征和影响包封率的因素

氧氟沙星在眼科临床广泛应用,本研究以氧氟沙星作为模型药物,采用水/油/水(w/o/w)的复乳化和溶剂扩散技术制备氧氟沙星聚乳酸-聚乙醇酸(PLGA)微囊,对影响包封率的工艺参数如药物浓度、PLGA使用量、初乳复乳的搅拌速率进行研究,并对微囊的粒径、表面电位和表面形态的理化性能进行了表征。测试结果表明,根据优化工艺制备的氧氟沙星PLGA微囊的平均粒径511.9±14.6nm,zeta电位-17.97±0.80mV,包封率54.2%,载药量1.94%。包封率随PLGA使用量、初乳搅拌速率的增加而上升,随内水相药物体积和浓度的增加而下降。通过优化的水/油/水(w/o/w)复乳化和溶剂扩散技术制备氧氟沙星PLGA载药微囊的粒度分布窄,载药量和包封率适中,具有较好的临床应用前景。     

低浓化医院中子照射器（IHNI-1）堆芯的物理方案设计

采用蒙特卡罗程序MCNP／4B模拟计算了功率为30kW的低浓化医院中子照射器的堆芯物理参数,设计了合理的堆芯布置方案、235U富集度、控制棒价值、后备反应性和停堆深度,得到固有安全性较高、寿期达10年且无需换料、采用低浓化UO2燃料的医院中子照射器的堆芯物理设计方案,为后续反应堆工程设计以及硼中子俘获治疗肿瘤用中子束的设计提供理论依据。     

磁性脂质体的制备及应用

磁性脂质体是掺入磁性载体材料的脂质体,由于其良好的载药性、磁靶向性以及生物相容性而受到广泛的研究.综述了磁性脂质体的制备方法,总结了磁性脂质体在靶向药物、热化疗、造影剂领域中的应用研究进展最后展望了磁性脂质体的发展方向.     

磁性脂质体的制备及应用研究进展

综述了纳米磁性粒子和磁性脂质体的制备方法,同时简要介绍了磁性脂质体在磁性分离、靶向药物、热疗、组织工程和造影剂等领域的应用进展.     

叶酸受体靶向的聚乳酸共聚物胶束的制备及性质研究

叶酸偶联的羟脯氨酸-乳酸共聚物(PLLA-PHpr-FA)是一种新型的叶酸受体靶向生物降解聚合物,研究PLLA-PHpr-FA自组装形成胶束的能力及胶束的性质。临界胶束浓度(CMC)用芘荧光探针测定,结果表明,CMC很低并依赖于乳酸/羟脯氨酸的比例。透射电子显微镜(TEM)显示共聚物胶束呈现典型的核/壳结构。动态激光光散射(DLS)测定粒径及粒径分布结果显示,粒径受乳酸/羟脯氨酸比例和丙酮量调控,但粒子几乎不受稀释的影响。用紫外分光光度法测定胶束的载药量和包封率表明,共聚物胶束对疏水性药物的包载较好。因此,PLLA-PHpr-FA胶束可以作为肿瘤靶向的药物载体。     

迈入新世纪的硼中子俘获疗法（BNCT）

扼要叙述进入21世纪之际,硼中子俘获疗法(boron neutorn capture therapy,BNCT)在国际范围内的一些显著进展,包括BNCT的临床定位、肿瘤复发的探索、硼浓度的定量探测、靶向掺硼药物的开发以及我国医院中子照射器的问世.这些BNCT长期开发中的瓶颈趋于缓解,预示了BNCT个性化与例行化的前景更为清晰.     

内水相结构对微球包封率及控释行为的影响

采用水-油-水双乳化溶剂挥发法制备了聚乳酸-羟基乙酸共聚物(PLGA)/氧氟沙星载药微球,并考察了介孔硅、透明质酸、多聚赖氨酸不同内水相成分对微球粒径及其分布、表面形态、包封率以及释放特性的影响。研究结果表明,采用该方法制备出了内部具有多孔结构的载药微球;透明质酸内水相组微球平均粒度最大,粒径分布最小;介孔硅和透明质酸的加入提高了微球包封率;3种内水相组的初期爆释均高于对照组;多聚赖氨酸内水相组释放速率最快,透明质酸内水相组释放速率最慢。释放拟合曲线表明,4组不同内水相的微球,在释放区间内,释放行为都符合Slogistic方程式。     

叶酸受体靶向的聚L-丙氨酸-聚乙二醇单甲醚嵌段共聚物的合成及表征

以端氨基聚乙二醇单甲醚(MPEG-NH2)为引发剂,聚合N-羧基-丙氨酸-环内酸酐(NCA)得到聚L-丙氨酸-聚乙二醇单甲醚嵌段共聚物(PLAM),并接枝叶酸,制得叶酸偶联的叶酸-聚L-丙氨酸-聚乙二醇单甲醚嵌段共聚物(FOL-PLAM).利用FT-IR、1HNMR等分析方法确认了聚合物PLAM和FOLPLAM的结构及...     

甘草酸羧甲基壳聚糖纳米粒的制备及其性能研究

通过正交试验设计优化钙离子交联法制备羧甲基壳聚糖纳米粒工艺条件,以透射电镜观察,纳米粒外观形态圆整;以激光粒度分析仪测定,纳米粒平均粒径为(131.2±5.27)nm;以高效液相色谱法测定,纳米粒包封率为(51.2±0.41)%,载药量为(16.7±0.29)%。对模型药物甘草酸的体外释放性能考察结果表明,所制备的纳米粒具有较好的控制药物释放的作用。     

硼中子俘获治疗人脑胶质母细胞瘤的前景和困惑

硼中子俘获疗法是一种可以选择性杀伤肿瘤细胞的放射疗法,其产生的α粒子对临床治疗新诊断和复发的脑胶质母细胞瘤有较好的疗效.发达国家20世纪五六十年代就已进入临床试验,但一直受到硼携带载体和中子源发展的限制.现就其治疗脑胶质母细胞瘤的前景做一综述.     

硼中子俘获疗法治疗脑胶质瘤及难治性垂体腺瘤的现状及展望

硼中子俘获疗法在脑胶质瘤治疗研究中已经取得很大进展,但由于脑胶质瘤的特性以及缺乏与肿瘤高亲和力的掺硼药物,硼中子俘获治疗的效果并不十分理想.此外,难治性垂体腺瘤具有很多与脑胶质瘤相同的特点,硼中子俘获疗法可能具有一定的意义.文章重点介绍硼中子俘获疗法治疗脑胶质瘤的研究现状和治疗难治性垂体腺瘤的可能性.     

胶质瘤细胞系摄取BPA的实验研究

目的:探讨BPA(2,2-双(4-羟基苯基)丙烷,Bisphenol A)浓度和温度对胶质瘤细胞系摄取和析出10B的影响.方法:将C6和U251两种胶质瘤细胞系,及大鼠正常脑胶质细胞培养在含不同浓度BPA(10B浓度分别为20、40、60、80、100 μg/mL)的培养基中24h后,采用感应耦合等离子体原子发射光谱(ICP-AES)法测定细胞内硼的含量;将C6细胞培养在含不同浓度BPA的培养基中培养24h后,更换为不含10B培养基,在不同温度条件(4、25、37℃)下继续培养,并分别于换液后的1、2、3h,用ICP-AES方法检测细胞内的硼含量.结果:细胞内硼浓度随培养基中BPA浓度的增加而增高,胶质瘤细胞内10B浓度约为正常胶质细胞的2.2倍;温度越高,细胞内硼析出速度越快.结论:BPA对胶质瘤细胞系具有一定亲和力;细胞对10B的析出速率具有温度依赖性.     

Fluorescent liposomes as contrast agents for in vivo optical imaging of edemas in mice

This study assesses if specially designed fluorescent liposomes can be used as contrast agent for near-infrared fluorescence (NIRF) optical imaging of cultured macrophages in vitro and for NIRF imaging of inflammatory processes, like edema, in an in vivo mouse model. Fluorescent liposomes are prepared by the film hydration and extrusion method using cholesterol, L-phosphatidylcholine, and the NIR fluorescent dye DY-676-C(18) ester. Photon correlation spectroscopy and flow cytometry reveal that fluorescent liposomes are structurally stable for up to 133 days. Distinct uptake/labeling of cultured murine J774 macrophages is demonstrated by confocal laser scanning microscopy (CLSM), flow cytometry, and macroscopic NIRF imaging system at wavelengths >670 nm. Moreover, CLSM analysis reveals fluorescence signals within intracellular compartments. Ear edema is induced in mice (n = 16) by subcutaneous injection of zymosan A. Whole-body NIRF imaging is performed after intravenous injection (0-24 h) of fluorescent liposomes (55 nmol dye per kg body weight). Distinctly higher fluorescence intensities (1613.6 +/- 61.7 a.u.) are detected at inflamed areas of diseased mice as compared to controls (892.8 +/- 19.4 a.u.). Furthermore, cell isolated from ear lavage reveals the presence of labeled F4/80 positive tissue macrophages. Taken together, the results indicate both that mouse macrophages labeled with fluorescent liposomes can be detected in vitro with fluoro-optical methods and that in vivo optical imaging of inflammatory processes with fluorescent liposomes as contrast agent is feasible. Possibly, early stages of other inflammatory diseases could also be detected by the proposed diagnostic tool in the long term.     

Studies on pectins as potential hydrogel matrices for controlled-release drug delivery

Polymeric hydrogels are widely used as controlled-release matrix tablets. In the present study, we investigated high-methoxy pectins for their potential value in controlled-release matrix formulations. The effects of compression force, ratio of drug to pectin, and type of pectin on drug release from matrix tablets were also investigated. The results of the in vitro release studies show that the drug release from compressed matrix tablets prepared from pectin can be modified by changing the amount and the type of pectin in the matrix tablets. However, compression force did not significantly affect the drug release. The mechanisms controlling release rate were discussed with respect to drug diffusion through the polymer matrices, but may be more complex.     

Self-assembled liquid crystalline nanoparticles as an ophthalmic drug delivery system. Part I: influence of process parameters on their preparation studied by experimental design

To develop self-assembled liquid crystalline nanoparticles as a drug delivery system for keratoconus treatment, a formulation containing riboflavin a water-soluble drug, two surfactants (poloxamer 407 and mono acyl glycerol – monoolein-) and water was optimized and prepared by emulsification and a homogenization process. A fractional factorial design was applied to estimate the main effects and interaction effects of five parameters on two responses, namely particle size and encapsulation efficiency. The five parameters are the temperature of the two phases, the duration of emulsification, the presence of heating during homogenization, the number of passes and pressure. The most influent parameters are the presence of heating during the homogenization and the pressure that led to the production of nanoparticles with an average size of 145?nm and an average encapsulation efficiency of 46%.