纳米粒沉淀法制备阳离子载基因PLA-PEG纳米粒

目的建立纳米粒沉淀法制备阳离子PLA-PEG纳米粒的方法。方法采用单因素设计考察不同影响因素对纳米粒粒径大小的影响,在单因素考察的基础上采用正交设计优化处方,制备了粒径较小,正电荷适中的阳离子PLA-PEG纳米粒。并对纳米粒的物理性质如物理形态,平均粒径,粒度分布,Zeta电位,DNA结合率,体外细胞转染能力等进行了考察。结果采用纳米粒沉淀法,通过优化处方和工艺制得的纳米粒外观圆整,呈类球形,大小均匀,平均粒径为89.7 nm,粒径分布指数为0.185,表面荷较高的正电荷,Zeta电位为+28.9 mV,能够高效的结合DNA且能够成功的转染Hela细胞。结论优化确定了纳米粒沉淀法制备阳离子PLA-PEG纳米粒的处方和工艺,可以制备满足细胞转染要求的阳离子载基因纳米粒。     

载白藜芦醇PLGA纳米粒的制备及其体内外评价

目的 通过聚乳酸-羟基乙酸共聚物[poly （lactic-co-glycolic acid）,PLGA]纳米粒的负载,改善白藜芦醇（resveratrol,RES）体内清除快、作用时间短的缺陷,延长RES镇痛作用时间。方法 利用复乳溶剂蒸发法制备PLGA纳米粒,载药后离心法除去游离药物;透射电镜考察其形态;激光粒度分析仪考察粒径、Zeta电位和稳定性; HPLC考察包封率和载药量;透析袋法考察其体外释药特性;热板法、醋酸扭体法及鼠尾测痛法考察其镇痛效果。结果 制备的PLGA@RES分布均一,无团聚现象,粒径为（210.90±1.76） nm,多分散指数为0.22±0.02,Zeta电位为（–21.81±0.75） mV;包封率与载药量分别为（89.62±2.52）%与（9.15±0.73）%;PLGA@RES较RES体外突释降低,缓释特性明显;药效学试验结果表明PLGA@RES起效快的特性仍未改变,镇痛作用时间明显延长。结论 PLGA@RES解决了RES体内清除快、作用时间短的缺陷,经过缓释后的PLGA@RES可发挥持久的镇痛效果,是一种RES的潜在递药系统。     

注射用载胸苷激酶基因质粒PLGA纳米粒的质量研究

制备了注射用载胸苷激酶（TK）基因质粒PLGA纳米粒的冻干剂，并对其形态、粒径、稳定性、体外抗核酸酶和抗超声能力等进行了观察。结果表明，纳米粒可提高TK基因对核酸酶和超声的抵抗能力。     

聚乙烯亚胺-聚甲基丙烯酸甲酯阳离子纳米粒介导基因转移的研究

目的研究聚乙烯亚胺-聚甲基丙烯酸甲酯(PEI-PMMA)纳米粒作为基因载体的性能，探讨阳离子纳米粒介导基因转移机制。方法用自由基聚合法制备PEI-PMMA阳离子纳米粒，扫描电镜观察粒子形态，zeta粒度仪测定粒径﹑表面电荷，凝胶电泳阻滞分析载基因能力和激光共焦扫描显微镜观察纳米粒介导的细胞内基因转移情况。结果PEI-PMMA纳米粒呈单分散球形，平均粒径为172 nm，zeta电位为+50.3 mV。当pGL3质粒与纳米粒以N/P为5∶1和20∶1形成复合物后纳米粒平均粒径分别为133和139 nm；zeta电位分别为+21.4和+33.7 mV。pGL3可完全与纳米粒形成复合物。PEI-PMMA纳米粒可携带pGL3质粒进入HeLa细胞，并突破吞噬小泡释放质粒于细胞质，最终质粒聚集于细胞核内进行表达。结论PEI-PMMA纳米粒通过内吞作用介导基因转移入靶细胞，可作为基因转移的非病毒型载体。     

载药纳米粒的研究进展

综述了聚合物、固体脂质及长循环3种纳米粒的载体材料、制备方法的研究进展。     

RP-HPLC法测定盐酸青藤碱PLGA纳米粒的包封率及载药量

目的：建立盐酸青藤碱PLGA纳米粒的包封率及载药量的测定方法。方法：SHIM-PACK VP-ODS柱,流动相为甲醇-10mol·L-1 NaH2PO4溶液（38∶62）,柱温为30℃,检测波长为262nm,流速1mL·min-1。结果：盐酸青藤碱在0.5～50μg·mL-1范围内线性关系良好,R2=0.9999,溶剂和辅料对其无明显干扰,平均回收率为95.31%,日内和日间RSD分别为1.31%和1.59%（n=5）。结论：该方法简便快速,准确可靠,可用于盐酸青藤碱PLGA纳米粒包封率及载药量的测定。     

右旋糖苷衍生物纳米粒对人乳腺癌细胞的转染作用研究

目的以右旋糖苷为起始反应物制备对人乳腺癌细胞具有高转染活性的右旋糖苷衍生物纳米粒非病毒基因载体。方法先将右旋糖苷40与高碘酸钠以不同的配比进行反应,生成醛基含量不同的氧化右旋糖苷;氧化右旋糖苷与精胺以不同的配比反应,共生成9种右旋糖苷衍生物纳米粒;以绿色荧光蛋白基因为报告基因、mda-mb-435人乳腺癌细胞为转染细胞,考察9种合成物的基因转染活性,从中选出转染活性最高的生成物。结果高碘酸钠与右旋糖苷40按摩尔比为0.8∶1反应生成氧化右旋糖苷;该氧化右旋糖苷再与精胺按1∶1的摩尔比继续反应,生成的终产物的转染效率最高。结论制备出了对mda-mb-435人乳腺癌细胞具有高转染活性的右旋糖苷衍生物纳米粒非病毒基因载体。     

紫杉醇PLGA纳米粒大鼠生物利用度的测定

目的制备紫杉醇PLGA纳米粒,以紫杉醇注射液为参比制剂,进行生物利用度考察。方法以乳化-溶剂挥发法制备紫杉醇纳米粒,用HPLC法测定全血中的药物浓度,计算紫杉醇纳米粒的生物利用度。结果紫杉醇纳米粒外观圆整,平均粒径为99.0nm,Zeta电位58.3mV,平均包封率为56.77%,载药量为7.10%。大鼠口服给药后,紫杉醇纳米粒的绝对生物利用度达到19.5%。结论纳米载药系统的制备有利于促进紫杉醇的吸收,提高了其口服生物利用度。     

复乳法制备胰岛素PLGA纳米粒影响包封率因素考察

以Poloxamer188为乳化剂，乙酸乙酯为有机溶剂，采用复乳法制备了胰岛素乳酸／羟基乙酸共聚物（PLGA）纳米粒，考察了乳化剂和PLGA的浓度。内水相中胰岛素的浓度为pH，溶剂挥发方法和内水相中加入聚乙烯醇（PVA）等实验各因素对胰岛素PLGA纳米粒包封率的影响。结果表明，乳化剂的浓度较高，PLGA的浓度较小，内水相的pH接近胰岛素的pI(5．3），胰岛素的浓度较低，缩短有机溶剂挥发时间及内水相中加入PVA有利于提高胰岛素的包封率，经实验条件优化后制备的胰岛素PLGA纳米纳平均粒径为149．6nm，多分散性系数小于0．1，包封率提高到42．8％。     

载药纳米粒透过血脑屏障机制的研究进展

血脑屏障是维持中枢神经系统内环境稳定的结构基础,有效保护脑组织避免外源性有害物质侵害,但也阻碍许多治疗药物进入脑内,限制了中枢神经系统药物的临床应用。如何有效透过血脑屏障成为此类药物发挥治疗作用的关键环节。纳米粒作为一种新型药物载体,能携载药物透过血脑屏障进入脑组织,提高脑内药物浓度,实现脑内靶向给药。本文对载药纳米粒及其透过血脑屏障机制的研究进展作一综述。     

Antibacterial activity of clarithromycin loaded PLGA nanoparticles

Novel drug delivery systems such as nanoparticles (NPs) have been proved to enhance the effectiveness of many drugs. Clarithromycin is a broad spectrum macrolide antibiotic, used in many infectious conditions like upper and lower respiratory tract infections, and skin and other soft tissue infections. This paper describes the preparation and enhanced in vitro antibacterial activities of clarithromycin loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles. A modified quasi-emulsion solvent diffusion (MQESD) method was used to prepare clarithromycin (CLR) NPs. The antibacterial activity of the NPs was evaluated using the agar well diffusion method against Escherichia coli (PTCC 1330), Haemophilus influenzae (PTCC 1623), Salmonella typhi (PTCC 1609), Staphylococcus aureus (PTCC 1112) and Streptococcus pneumoniae (PTCC 1240). The inhibition zone diameters related to each nano formulation were compared with those for untreated CLR at the same concentrations. The results indicated that the mean inhibition zone diameters of NPs against all the bacteria tested were significantly higher than those of untreated CLR, particularly in the case of S. aureus. The increased potency of CLR NPs may be related to some physicochemical properties of NPs like modified surface characteristics, lower drug degradation, and increased drug adsorption and uptake.     

洛伐他汀-PLGA纳米粒的制备及其性质

目的采用星点设计优化洛伐他汀-聚(乳酸-羟基乙酸)共聚物[poly(lactic-co-glycolic acid),PLGA]纳米粒的制备工艺。方法采用纳米沉淀法制备纳米粒,以药物在有机相中的浓度、水相与有机相的体积比、PLGA与药物的用量比为自变量,以载药量、包封率和药物利用率为因变量,计算"总评归一值",根据星点设计原理进行试验安排,对结果分别进行多元线性回归和二项式拟合,效应面法选取最佳工艺条件进行预测分析。结果各指标与"总评归一值"的二项式拟合方程均优于多元线性回归方程,根据优化工艺制备的洛伐他汀-PLGA纳米粒的载药量、包封率和药物利用率分别为(1.70±0.09)%、(86.83±1.75)%和(17.48±0.52)%,纳米粒平均粒径为122 nm,各指标实测值与预测值偏差较小。结论星点设计可用于洛伐他汀-PLGA纳米粒制剂处方的优化,所建立的数学模型预测性良好。     

盐酸维拉帕米PLGA纳米粒的成型工艺及制剂学性质研究

目的 优化影响盐酸维拉帕米乳酸/羟基乙酸共聚物(PLGA)纳米粒成型工艺的参数,并评价优化工艺后所制纳米粒的制剂学性质.方法 采用O/W超声乳化-溶剂挥发法制备盐酸维拉帕米PLGA纳米粒(VRP-PLGANP),以粒径、包封率和载药量为评价指标,采用单因素试验系统考察PLGA浓度、PLGA/VRP质量比、PVA浓度、有机相中丙酮浓度、外水相pH、内外相(O/W)体积比、探头超声时间、旋蒸时间共8个参数对纳米粒成型工艺的作用规律.结果 用优化处方工艺制备的纳米粒的包封率和载药量分别为65.78%±6.32%和22.75%±1.48%、平均粒径为150.4±6.9 nm、PDI=0.070±0.018(n=3),体外释放规律符合Weibull方程,具有一定的缓释特性.结论 所用方法可用于制备载两亲性药物的PLGA纳米粒.     

pDNA loaded calcium phosphate nanoparticles: highly efficient non-viral vector for gene delivery

Nanoparticles of calcium phosphate encapsulating plasmid DNA (pDNA) of size 100-120 nm in diameter were prepared. XRD studies of these nanoparticles showed them to be crystalline in nature having hydroxyapatite structure. The maximum loading of pDNA and its release from nanoparticles were studied using gel electrophoresis. The time dependent size measurement of these particles demonstrated that these particles show strong aggregational behaviour in aqueous dispersion. Calcium phosphate nanoparticles were found to be dissolved even in low acidic buffer (pH 5.0) releasing the pDNA, which suggested that DNA release from these particles in the endosomal compartment was possible. In vitro transfection efficiency of these calcium phosphate nanoparticles was found to be higher than that of the commercial transfecting reagent Polyfect.     

Unraveling the cytotoxic potential of Temozolomide loaded into PLGA nanoparticles

Background

Nanotechnology has received great attention since a decade for the treatment of different varieties of cancer. However, there is a limited data available on the cytotoxic potential of Temozolomide (TMZ) formulations. In the current research work, an attempt has been made to understand the anti-metastatic effect of the drug after loading into PLGA nanoparticles against C6 glioma cells.Nanoparticles were prepared using solvent diffusion method and were characterized for size and morphology. Diffusion of the drug from the nanoparticles was studied by dialysis method. The designed nanoparticles were also assessed for cellular uptake using confocal microscopy and flow cytometry.

Results

PLGA nanoparticles caused a sustained release of the drug and showed a higher cellular uptake. The drug formulations also affected the cellular proliferation and motility.

Conclusion

PLGA coated nanoparticles prolong the activity of the loaded drug while retaining the anti-metastatic activity.     

Brain delivery and systemic effect of cationic albumin conjugated PLGA nanoparticles

Cationic bovine serum albumin (CBSA)-conjugated poly(ethylene glycol)–poly(d,l-lactide-co-glycolide) (PEG–PLGA) nanoparticle (CBSA–NP) is an innovative protein and genes carrier for brain delivery. In the present study, single factor and orthogonal experiments have been carried out to optimize the formulation of preparing CBSA. Effects of varying formulation parameters on NP size were also determined. Quantitative and qualitative analyses of CBSA–NP and NP uptake by brain capillary endothelial cells were evaluated using 6-coumarin as the fluorescent probe. Uptake process was demonstrated to be dependent on the concentration of NPs, incubation time, and energy. Biodistribution indicated that our optimized CBSA–NP was efficiently taken up by the brain tissue, but did not lead to a general enhanced uptake into all tissues. Splenic accumulation of CBSA–NP was prominently decreased when compared with results from our previous studies. The optimized CBSA pI value was 8.9 and the achieved CBSA–NP obtained a concentration that was 2.31-fold compared with NP. Moreover, the splenic AUC of CBSA–NP was only 0.29-fold compared with that of NP. These results indicated that CBSA–NP was an ideal carrier for targeted brain delivery.     

G-CSF loaded biodegradable PLGA nanoparticles prepared by a single oil-in-water emulsion method

A new formulation method was developed for preparing poly(D,L-lactic-co-glycolic acid) (PLGA) nanoparticles loaded with recombinant human granulocyte colony-stimulating factor (rhG-CSF). Lyophilized rhG-CSF powder and PLGA polymer were directly co-dissolved in a single organic phase, and the resulting solution was dispersed into an aqueous solution. PLGA nanoparticles encapsulating rhG-CSF were produced by a spontaneous emulsion/solvent diffusion method. In this manner, rhG-CSF was molecularly dissolved in the polymer phase. Release profile of rhG-CSF from PLGA nanoparticles was compared with those from two kinds of PLGA microparticles which were separately prepared by either single oil-in-water (O/W) or double water-in-oil-in-water (W/O/W) emulsion technique. The sizes of rhG-CSF loaded nanoparticles, O/W microparticles, and W/O/W microparticles were about 257 nm, 4.7 microm, and 4.3 microm, respectively. For rhG-CSF nanoparticles, about 90% of encapsulated rhG-CSF was released out in a sustained manner from PLGA nanoparticles over a 1 week period, but for rhG-CSF microparticles, only about 20% of rhG-CSF could be released out during the same period. Reversed phase and size exclusion chromatograms revealed that the structural integrity of released rhG-CSF from nanoparticles was nearly intact, compared to that of native rhG-CSF.     

PLGA nanoparticles loaded with KMP-11 stimulate innate immunity and induce the killing of Leishmania

We recently demonstrated that immunization with polyester poly(lactide-co-glycolide acid) (PLGA) nanoparticles loaded with the 11-kDa Leishmania vaccine candidate kinetoplastid membrane protein 11 (KMP-11) significantly reduced parasite load in vivo. Presently, we explored the ability of the recombinant PLGA nanoparticles to stimulate innate responses in macrophages and the outcome of infection with Leishmania braziliensis in vitro. Incubation of macrophages with KMP-11-loaded PLGA nanoparticles significantly decreased parasite load. In parallel, we observed the augmented production of nitric oxide, superoxide, TNF-α and IL-6. An increased release of CCL2/MCP-1 and CXCL1/KC was also observed, resulting in macrophage and neutrophil recruitment in vitro. Lastly, the incubation of macrophages with KMP-11-loaded PLGA nanoparticles triggered the activation of caspase-1 and the secretion of IL-1β and IL-18, suggesting inflammasome participation. Inhibition of caspase-1 significantly increased the parasite load. We conclude that KMP-11-loaded PLGA nanoparticles promote the killing of intracellular Leishmania parasites through the induction of potent innate responses.From the Clinical EditorIn this novel study, KMP-11-loaded PLGA nanoparticles are demonstrated to promote the killing of intracellular Leishmania parasites through enhanced innate immune responses by multiple mechanisms. Future clinical applications would have a major effect on our efforts to address parasitic infections.