依他硝唑纳米粒对乏氧肿瘤细胞辐射增敏作用的研究

目的 制备出具有生物活性并可控制释放的依他硝唑纳米粒,探讨其对乏氧人乳腺癌细胞(MCF-7)和人子宫颈癌细胞(HeLa)的辐射增敏作用。方法 采用复乳溶剂挥发法制备聚乳酸-聚羟基乙酸共聚物(PLGA)包裹的依他硝唑纳米粒,高效液相色谱分析纳米粒的载药率、包封率和模拟体外释药,透射电镜研究纳米粒的形态,激光衍射粒度分析仪检测纳米粒的粒径分布。经乏氧处理的MCF-7和HeLa细胞与依他硝唑纳米粒和药物单体共培养,采用平板克隆形成实验检验其辐射增敏作用。结果 成功制备依他硝唑纳米粒,呈光滑球形,粒径分布在90～190 nm之间,载药率为1.66％,包封率为18.02％,模拟体外释药曲线呈双相,即在爆发释放之后为缓慢释放。同依他硝唑纳米粒和药物单体共培养的乏氧MCF-7和HeLa细胞克隆形成能力照射后明显降低,依他硝唑纳米粒作用更为显著。结论 具有生物活性的依他硝唑从纳米粒中以可控的方式被释放,有效地增加了乏氧肿瘤细胞的辐射敏感性,为辐射增敏剂的临床应用提供了一种新的给药方式。     

5-FU纳米微粒的制备及其释药特性研究

目的 制备一种新型的载氟尿嘧啶(5-FU)纳米微粒并对其体内释药特性进行研究.方法 运用聚合物交联法制备出壳聚糖载氟尿嘧啶纳米粒,通过扫描电镜、激光粒度分析仪对其表征进行检测,紫外分光光度法测定载药量,高效液相色谱法检测体内的释药特性.结果 壳聚糖载氟尿嘧啶纳米粒呈圆形或椭圆形,分散性良好,粒径在120～150nm;载药量为31.000%±0.001%;壳聚糖-5-FU纳米粒注射入兔体内后,初期突释相约在1.5h,峰浓度为5 069.6μg/L,随即进入缓释相,浓度维持在76μg/L,时间长达48h.结论 壳聚糖纳米药物载体可改变5-FU在体内的药代动力学行为,延长其循环时间,具有良好的缓释作用.     

氟尿嘧啶纳米乳剂的制备与性质

目的研究氟尿嘧啶大豆油纳米乳剂的相图、稳定性、载药量及药物的体外释放特点。方法在三元相图的基础上优选出制备纳米乳剂的最佳处方,用透射电子显微镜观测纳米乳剂粒径的大小,HPLC法测定纳米乳剂中氟尿嘧啶的含量及体外释放性能。结果纳米乳剂颗粒为圆形或椭圆形,粒径范围20±10nm,药物包裹率85.06%,体外11h药物释放50%,50h缓释95%。结论本实验制备的纳米乳剂性质稳定,与游离的药物相比有明显的缓释性能。     

紫杉醇纳米粒对乏氧MCF-7细胞的辐射增敏作用

目的 制备出具有生物活性并可控制释放的紫杉醇纳米粒,探讨其对乏氧人乳腺癌细胞(MCF-7)的辐射增敏作用。方法 采用单乳溶剂挥发法制备聚乳酸-聚羟基乙酸共聚物［Poly (D,L- lactide-co-glycolide),PLGA］包裹的紫杉醇纳米粒,高效液相色谱分析纳米粒的载药率、包封率和模拟体外释药,扫描电镜研究纳米粒的形态。经乏氧处理的MCF-7细胞与紫杉醇纳米粒共培养,通过细胞形态和细胞周期变化来分析从纳米粒中释放出来的紫杉醇的生物活性,采用平板克隆形成实验检验其辐射增敏作用。结果 成功制备出的紫杉醇纳米粒呈光滑球形,粒径分布为200～800 nm,载药率为4.5%,包封率为85.5%,模拟体外释药曲线呈双相,即在暴发释放之后为缓慢释放。同紫杉醇纳米粒共培养的乏氧MCF-7细胞形态发生改变,极性增加,呈梭形,并且G₂期细胞比例升高,克隆形成能力明显降低。结论 本研究证实具有生物活性的紫杉醇从纳米粒中以可控的方式被释放,有效地增加了乏氧MCF-7细胞的辐射敏感性,为辐射增敏剂的临床应用提供了一种新的给药方式。     

海藻酸钠胰岛素纳米粒对糖尿病大鼠的降血糖作用

目的研究海藻酸钠胰岛素纳米粒的制备方法及其对糖尿病大鼠的降血糖作用。方法采用离子交联法制备海藻酸钠胰岛素纳米粒,分别用透射电镜和纳米粒度分析仪测定纳米粒形态和粒径。建立Wistar大鼠糖尿病模型,观察海藻酸钠胰岛素纳米粒灌胃给药后的降血糖作用。结果制备得到的纳米粒形态为球形或近球形,粒径为236.4±19.3nm,胰岛素包封率为78.5%±6.1%,载药量为22.6%±4.4%。降血糖试验表明,海藻酸钠胰岛素纳米粒灌胃(26U/kg)后7h,血糖含量开始下降,这种降血糖作用可维持12h,其中血糖维持在正常水平的时间可达6h(血糖值≤7.0mmol/L)。结论海藻酸钠胰岛素纳米粒具有一定的缓释功能,灌胃给药后可降低糖尿病大鼠血糖水平。     

具核磁共振成像功能的可再生介孔硅作为抗肿瘤药物新型载体的性能研究

目的 构建一种具核磁共振成像（magnetic resonance imaging,MRI）功能的再生含钆介孔硅纳米粒(gadolinium-containing renewable mesoporous silica nanoparticles,rMSN-Gd),探究其作为抗肿瘤药物载体的可行性。方法 以稻壳为硅源,通过软模板法制备rMSN Gd纳米粒。对新型纳米粒形态、粒度、介孔状态、元素含量、生物相容性、载药量、体外释放度等方面进行表征,并检测其在体外与荷瘤BALB/c裸鼠体内MRI成像特点。以抗肿瘤药物盐酸阿霉素为模型药物,以人肝癌HepG2细胞与人肺癌A549细胞为模型,对纳米载体的细胞摄取、体外抗肿瘤活性进行评价。结果rMSN-Gd纳米粒呈球形,分散性良好,平均粒径为150 nm,钆含量为4.7%wt,材料具有良好生物相容性。rMSN-Gd体外与体内均有较好MRI成像能力。载药后,其释药速率呈pH依赖性。纳米粒的细胞摄取效率较高,其对HepG2与A549细胞毒性显著高于游离阿霉素。结论 多功能纳米材料rMSN-Gd可以成功作为药物递送系统并整合MRI成像功能实现诊断治疗一体化。     

不同粒径石杉碱甲纳米粒的制备及其在小鼠体内分布特性研究

目的研究不同粒径石杉碱甲纳米粒在小鼠体内的分布情况。方法以聚乳酸-羟基乙酸（PLGA）为载体材料,采用乳化溶剂挥发法制备不同粒径的石杉碱甲纳米粒;采用小动物活体成像技术研究不同粒径纳米粒在小鼠体内的分布情况。结果制备了粒径从43．1nm到316nm的石杉碱甲纳米粒,载药量从0．11％到2．42％。不同粒径纳米粒在小鼠体内的动态分布研究表明,粒径为50nm左右的纳米粒可以分布于全身各个器官,并能透过血脑屏障,且能起到缓释的效果;粒径为100～300nm左右的纳米粒主要分布于肝脏,且较难透过血脑屏障。结论该研究为进一步开发高效、低毒的石杉碱甲新型制剂提供了重要参考。     

血管内皮生长因子长效缓释微球不同配比对体外释放行为改善的研究

目的用生物可降解聚乳酸羟基乙酸共聚物(PLGA)制备载药微球包埋血管内皮生长因子(VEGF),并探索不同配比对释放行为的影响。方法采用不同分子量的PLGA制备不同粒径的载药微球,并经载药微球的合理配比改善其体外释放行为,达到优化工艺、降低成本的目的。结果载药微球粒径约为20μm、分子量10 kU:24 kU的配比为1:2组,粒径为20μm、分子量为24 kU和分子量为10 kU、粒径为6μm的载药微球配比为2:1组的体外释放突释较低,且在14 d内呈线性的零级释放趋势,体外释放行为得到改善。结论 VEGF长效缓释PLGA微球经优化配比后的持续释放能力较传统VEGF微球明显提高。     

载药肿瘤微血管栓塞颗粒制备及其抗肿瘤作用初探

目的 制备加载化疗药物的纳米微粒,研究其性质及体外释药特点,探讨体外对人原代肝癌细胞的毒性作用,为用于临床肿瘤微血管介入栓塞提供理论依据.方法 以盐酸吉西他滨-复方甘草酸苷共聚物为药物载体,加载化疗药物多柔比星制备载药纳米微粒.扫描电镜观察微粒形态,纳米粒度电位仪检测微粒粒径分布及电位,高效液相色谱法计算载药率及包封率,透析袋扩散法作体外释放动力学试验,体外考察纳米药物稳定性及释药性能.CCK-8法检测纳米药物在体外对人原代肝癌细胞的毒性作用.结果 本法制备的载药纳米微粒外观呈圆球形,平均粒径(62.83±5.19) nm,平均电位-17.9 mV;载药率、包封率分别为3.16％、66.27％;有良好的缓释特性,对人原代肝癌细胞生长有明显抑制作用.结论 本法制备的载药纳米微粒具有较好的药物缓释性及抗肿瘤效应,是一种具有良好应用前景的抗肿瘤纳米药物.     

葛根素肠溶纳米粒的制备及体外释放度研究

目的制备葛根素肠溶纳米粒,并对其体外释放度进行考察。方法采用离子交联法制备葛根素肠溶纳米粒,HPLC法测定药物的包封率及体外释放度,透射电镜考察纳米粒的表面形态,激光粒度分析仪测定粒径分布。结果制备的纳米粒,粒径较小,分布均一,包封率较高,理化性质合乎要求,并在pH7.2的磷酸盐缓冲液中释放达到70%以上。结论葛根素肠溶纳米粒体外释药良好,能达到良好肠溶效果。     

131I标记共载两种靶向药物的多功能纳米载体的构建

目的构建131I标记的、共载17-丙烯胺基-17-去甲氧基格尔德霉素（17-AAG）与Torin2两种分子靶向性药物的新型多功能介孔二氧化硅（mSiO₂）纳米载体,测定其表征,了解其释药动力学,以及甲状腺未分化癌（ATC）细胞对其摄取的情况。方法采用传统的模板法制作mSiO₂,按照浓度比为1:1的比例装载两种靶向药物17-AAG与Torin2,并在其表面进行氨基化修饰后连接胎牛血清白蛋白（BSA）,测定其基本表征、药物的载药量及包封率。采用高效液相色谱法分析纳米载体所载药物的体外释放情况。采用氯胺T法对纳米载体进行131I标记,测定其标记率及放化纯度。通过核素胞内摄取定量实验了解该纳米载体被ATC细胞的摄取及滞留情况。采用SPSS19.0统计学软件,对数据进行独立样本t'检验。结果成功制备mSiO₂并完成装载（17-AAG+Torin2）@mSiO₂-BSA-131I纳米载体,经测定得到两者的有效直径分别约为170~250 nm和200~300 nm,并证实所得纳米载体的分散性好且具有理想的球形形态。131I标记率为66.31%~78.25%,放化纯度为98.80%~99.42%,mSiO₂对17-AAG及Torin2的载药量分别为（7.31±0.22）%和（6.04±0.79）%,包封率分别为（86.21±1.32）%和（85.17±2.05）%。证实所得纳米载体对17-AAG与Torin2均具有一定的缓释效果。ATC细胞内核素摄取定量实验结果显示（17-AAG+Torin2）@mSiO₂-BSA-131I可被细胞快速摄取且于3 h时达摄取高峰,其细胞摄碘量明显高于Na131I溶液,差异有统计学意义（t=32.63~109.31,均P < 0.01）。结论mSiO₂纳米载体可以实现两种靶向药物的共载及131I的标记,且具有一定的药物缓释作用,ATC细胞能够明显、快速地摄取（17-AAG+Torin2）@mSiO₂-BSA-131I。     

Magnetic poly(lactide‐co‐glycolide) and cellulose particles for MRI‐based cell tracking

Biodegradable, superparamagnetic microparticles and nanoparticles of poly(lactide‐co‐glycolide) (PLGA) and cellulose were designed, fabricated, and characterized for magnetic cell labeling. Monodisperse nanocrystals of magnetite were incorporated into microparticles and nanoparticles of PLGA and cellulose with high efficiency using an oil‐in‐water single emulsion technique. Superparamagnetic cores had high magnetization (72.1 emu/g). The resulting polymeric particles had smooth surface morphology and high magnetite content (43.3 wt % for PLGA and 69.6 wt % for cellulose). While PLGA and cellulose nanoparticles displayed highest r values per millimole of iron (399 sec^?1 mM^?1 for cellulose and 505 sec^?1 mM^?1 for PLGA), micron‐sized PLGA particles had a much higher r per particle than either. After incubation for a month in citrate buffer (pH 5.5), magnetic PLGA particles lost close to 50% of their initial r molar relaxivity, while magnetic cellulose particles remained intact, preserving over 85% of their initial r molar relaxivity. Lastly, mesenchymal stem cells and human breast adenocarcinoma cells were magnetically labeled using these particles with no detectable cytotoxicity. These particles are ideally suited for noninvasive cell tracking in vivo via MRI and due to their vastly different degradation properties, offer unique potential for dedicated use for either short (PLGA‐based particles) or long‐term (cellulose‐based particles) experiments. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.     

Intramuskuläre Applikation von Depotmedikamenten

Drug-loaded microparticles (microspheres) based on poly(lactic-co-glycolic) acid (PLGA) are used for long-term drug release mainly after intramuscular injection. The particles are rarely seen in histological sections from autopsy specimens. The case of a 65-year-old woman who died following a generalized infection and erysipelas is presented where the origin of histologically detected microparticles could only be identified with great difficulty.     

In vitro release of vascular endothelial growth factor from gadolinium-doped biodegradable microspheres.

A drug delivery vehicle was constructed that could be visualized noninvasively with MRI. The biodegradable polymer poly(DL-lactic-co-glycolic acid) (PLGA) was used to fabricate microspheres containing vascular endothelial growth factor (VEGF) and the MRI contrast agent gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA). The microspheres were characterized in terms of size, drug and contrast agent encapsulation, and degradation rate. The PLGA microspheres had a mean diameter of 48 +/- 18 microm. The gadolinium loading was 17 +/- 3 microg/mg polymer and the VEGF loading was 163 +/- 22 ng/mg polymer. Electron microscopy revealed that the Gd was dispersed throughout the microspheres and it was confirmed that the Gd loading was sufficient to visualize the microspheres under MRI. VEGF and Gd-DTPA were released from the microspheres in vitro over a period of approximately 6 weeks in three phases: a burst, followed by a slow steady-state, then a rapid steady-state. Biodegradable Gd-doped microspheres can be effectively used to deliver drugs in a sustained manner, while being monitored noninvasively with MRI.     

Photodynamic antimicrobial chemotherapy through photosensitizers loaded poly-l-glycolic acid on Candida albicans in denture lining material: Release,biological and hardness study

AimThe aim of this in-vitro study was to formulate poly-l-glycolic acid nanoparticles loaded with methylene blue (PLGA-MB) and to characterize their physicochemical features, photosensitizer-release kinetics and antimicrobial efficacy against Candida albicans (C. albicans) after incorporating in polymethyl methacrylate (PMMA) denture lining materials.Material and methodsMB-PLGA nanoparticles were synthesized according to the modified nanoprecipitation method. The morphological characterization of the nanoparticles was studied under scanning and transmission electron microscope. Particle size, surface charge, polydispersity index (PDI) and MB release were evaluated. The effect of 660 nm semiconductor AlGaInP diode laser on C. albicans was studied in vitro. The PMMA was weighed and PLGA free and PLGA-MB were added in the lining material according to the weight percentage as 2.0 wt.% and 5.0 wt.% and tested for the diameter of the inhibition zones of C. albicans growth and shore A hardness.ResultsHomogenous spherical nanoparticles with round morphology with size ranging between 60–80 nm were observed while PLGA-MB were seen to have irregular structure within the nanoparticle under TEM. PLGA-Free was larger in size than the loaded PLGA (∼62 nm) that evidenced reduction in size by adding the MB photosensitizer. PDI recordings reduced from 0.198 for the PLGA-Free nanoparticles to 0.164 for the PLGA-MB nanoparticles. The entrapment efficiency of MB inside PLGA showed an average percentage of ∼75 % uptake that resulted in the overall loading of ∼15 %. An overall inhibition of 78 %, 41 % and 28 % of C. albicans growth was seen with a concentration of 0.1, 0.5 and 1.0 μg/mL, respectively. The application of PLGA nanoparticles loaded with MB evidenced >75 % of C. albicans. MB incorporation did not lead to a clinically relevant change on shore A hardness.ConclusionPLGA loaded with MB is believed to have promising target therapy against C. albicans in denture soft lining materials in terms of PACT in vitro. The synergistic association between PLGA and MB proved enhanced antifungal activity. PLGA-MB could be an important tool in nanobiotechnology and photodynamic therapy for novel formulations with higher antimicrobial efficacy and improved drug delivery from denture soft lining materials.     

Imaging Guided PTT-PDT Combination Therapy of Prostate Cancer Utilizing Ag2S-Fe3O4 Hybrid Nanoparticles and 5-ALA

Superparamagnetic iron oxide nanoparticles (SPIONs) and luminescent semiconductor quantum dots (QDs) have been at the center of biomedicinal research in the last decades, utilized for imaging, diagnostics, and therapy. SPIONs are known and utilized for magnetic resonance imaging (MRI), magnetic hyperthermia and photothermal therapy (PTT) and drug delivery [1, 2]. QDs, on the other hand, are very well established in the bioimaging and theranostics as an alternative to organic fluorophores due to their unique properties such as narrow emission bands, size-tunable and strong fluorescence and excellent photostability [3, 4]. Light-induced localized therapies, namely photodynamic therapy (PDT) and PTT, emerge as an alternative and/or complementary treatments along with conventional chemotherapy in the field of cancer therapeutics [5, 6]. Hybrid nanoparticles composed of magnetic-luminescent properties are highly appealing as they provide dual-imaging ability and enhanced photothermal properties, along with being excellent drug delivery vehicles [7]. In this study, luminescent-superparamagnetic Ag₂S-Fe₃O₄ (AS-SPION) hybrid nanoparticles were developed via a simple ligand exchange method using 2-mercaptopropionic acid (2-MPA) coated AS QDs replacing lauric acid (LA) coating on SPIONs. Synthesis of both particles and the hybrids were previously reported [8, 9]. Final hybrids were then loaded with 5-aminolevulinic acid (5-ALA), which is an FDA approved natural precursor of PDT agent protoporphyrin IX (PPIX), to achieve imaging guided enhanced PDT-PTT combination therapy on prostate cancer cells. By loading 5-ALA to nanoparticles, its bioavailability and the efficiency of the combination therapy can be increased. The hydrodynamic size of the hybrids were less than 100 nm and they had strong emission in the medical imaging window (850-900 nm). The comparative PTT potential of the QDs vs. hybrids were initially investigated in the solution by irradiating the samples at 640 nm (215 mW) and 808 nm (400 mW) at different Ag concentrations. After determining the optimal PTT conditions in the solution, followed by in-vitro dark cytotoxicity of AS-2MPA QDs, AS-SPION hybrids, free ALA, and AS-SPION-ALA particles for LnCap, PC3 and Du145 cell lines, best treatment parameters were defined. Additionally, L929 cells were used to prove the non-toxic nature of the particles. PDT-PTT combination therapy was applied via co-irradiation of the cells with 640 and 808 nm laser at 300 mW and 700 mW power, respectively, for 5 minutes and cell death was evaluated with standard MTT assay. Additionally, cell death mechanisms were investigated in terms of ROS generation, apoptosis/necrosis and live/dead imaging. This study was focused on the determination of advantages of having hybrid nanoparticles providing dual-modality, enhanced phototherapy effect and the difference generated from combination therapy in comparison to monotherapies in the treatment of prostate cancer.     

口服降钙素微粒制备工艺的研究

目的:制备口服降钙素微粒给药系统.方法:选用氨基酸环合脱水、环二聚化的方法合成二酮哌嗪,以二酮哌嗪作为包裹材料采用固化凝聚法制备降钙素微粒,通过正交设计筛选降钙素微粒的制备工艺,并对其物理形态、体外释放进行了研究.结果:微粒的物理性质稳定,在水溶液中的分散性好,平均粒径1～3μm,药物回收率74%,微球主药含量1.36%,体外释放符合零级方程.结论:此微粒系统在低pH条件下稳定,在生理环境中可溶解,可作为在胃液中不稳定药物特别是蛋白质和多肽类药物口服给药载体.