首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 656 毫秒
1.
目的 利用天然抗菌剂来保护食品品质和延长食品的货架期。方法 研究利用玉米醇溶蛋白自组装的特性包覆香芹酚植物精油,然后用酪蛋白酸钠作为稳定剂来制备载香芹酚复合纳米粒子。结果 玉米醇溶蛋白纳米颗粒对香芹酚具有良好的包封率(71.52%~80.09%)。扫描电子显微镜(SEM)显示香芹酚复合纳米粒子分布均匀,呈球形,粒径为80~220 nm。同时,包覆香芹酚的纳米粒子具有良好的复溶性、储存稳定性和抗氧化性能,并且对金黄色葡萄球菌、大肠杆菌表现出良好的抗菌性能。结论 将该复合纳米颗粒应用于食品包装中,可有效地提高食品的抗氧化特性和抗菌性,抑制食品腐败变质、延长食品货架期,在食品工业中具有潜在的应用前景。  相似文献   

2.
肽聚糖制剂对日本对虾非特异免疫因子的作用   总被引:7,自引:0,他引:7  
用含不同浓度肽聚糖制剂的饵料投喂日本对虾 ,养殖 30d后取对虾血淋巴 ,分析血清中溶菌活力、凝集活力、酚氧化酶活力、超氧化物歧化酶活力、溶血活力。结果显示 :添加肽聚糖饵料组对虾比对照组对虾血清中的酚氧化酶活力、凝集活力均显著提高 (P <0 .0 5 ) ,高浓度肽聚糖饵料组 (1× 1 0 - 3)对虾血清溶血活力显著高于低浓度组及对照组中对虾的溶血活力 (P <0 .0 5 ) ;试验组与对照组中对虾的溶菌活力、总超氧化物歧化酶活力差异不明显 (P >0 0 5 )。表明饵料中使用一定浓度的肽聚糖可以通过提高对虾血清中酚氧化酶等因子活力而达到提高非特异免疫力的目的  相似文献   

3.
Ni-P-SiC(纳米)化学复合镀层的组织与性能   总被引:12,自引:0,他引:12  
利用化学镀方法制备了Ni-P-SiC(纳米)复合镀层,研究了镀液中纳米SiC微粒的含量对复合镀层组织与性能的影响,结果表:由于纳米SiC的加入,使复合镀时的镀速加快,原因是液固界面增加,从而增加了有效催化面积.由于镀层中纳米SiC的存在,使复合镀层的硬度得到显著提高,镀态下硬度可达1000~1100HV,退火处理后则可达到1650HV.与微米SiC复合镀层相比,纳米复合镀层的耐磨性也有明显改善.用DSC分析了镀层的晶化规律,发现纳米复合镀层的晶化温度大幅度提高.  相似文献   

4.
目的:建立测定阿莫西林胶囊在不同溶出介质中溶出曲线的方法。方法:采用HPLC法,色谱柱为Inertsil ODS-SP,5μm,4.6*250mm;流动相0.1361%醋酸钠溶液(用醋酸调节pH为4.5)-甲醇(947:53);检测波长:230 nm。溶出介质分别为pH1.2、pH4.0、pH6.8、水,转速100rpm,37℃。当溶出介质为pH1.2时,在取样管中预加醋酸钠溶液对溶出液进行中和。对阿莫西林胶囊溶出液进行测定并计算累计溶出度,绘制溶出曲线。结果:阿莫西林浓度在24.71-370.6μg/mL范围内有良好的线性关系(R2=0.9998),各溶出介质中的回收率在100.02%-100.41%,RSD均1%。结论:该方法简便可行,解决了阿莫西林在酸性条件下检测不稳定的问题,可用于阿莫西林胶囊在不同溶出介质中溶出曲线的测定。  相似文献   

5.
选用聚乳酸(PLA)为骨架基体,聚乙二醇(PEG)6000为致孔剂,用热熔挤出技术(HME)制备了难溶性药物双氯芬酸钠(DS)的固体分散物。通过改变PEG6000与DS含量,比较了对DS体外溶出速率的影响。结果发现,DS的溶出速率随着PEG6000与DS含量的增加而增加,且呈现良好的线性关系。当PLA、PEG6000、DS质量分数为67%、30%、3%时,体系18d药物溶出度为76.5%,若将DS质量分数提高到5%或将PEG6000质量分数提高到40%,则体系分别在4d和3d即达到最大溶出度。文中还对体系中DS的分散机制进行了研究,发现DS主要分散于PEG6000中,而PLA作为骨架材料有效稀释了药物浓度,并延长了药物的释放时间。  相似文献   

6.
粉体技术在中药中的应用   总被引:6,自引:0,他引:6  
简要介绍了粉体技术在中药加工中的应用,列举了粉体技术在中药制剂工艺和制剂疗效中所产生的影响,同时阐述了超微粉碎加工技术在中药现代化中的作用,简介了微米中药、纳米中药,并且引用中药超微粉碎一些实验研究,证明中药经超微粉碎后细粉比粗粉溶出的速度快,并且有效成分的溶出比较均匀。  相似文献   

7.
郑国渠  李波 《材料导报》2008,22(6):121-124
利用二次阳极氧化法在纯铝表面构建出具有纳-纳双重层级结构的阳极氧化膜.溶去一次阳极氧化膜所形成的纳米坑为一级结构,二次阳极氧化形成的纳米孔为二级结构.纳米坑和纳米孔的直径取决于阳极氧化电压、电解质种类、电解液温度等工艺条件,并在一定范围内独立可调.延长一次氧化时间可以提高纳米坑阵列的规整度;延长二次氧化时间将使一级结构即纳米坑的深度变浅.  相似文献   

8.
本发明涉及水性聚氨酯脲(PUU)催溶胶改性纳米CaCO3杂化水分散液的制备方法。其制备特点在于,以粒径10nm~100nm的硅溶胶改性纳米CaCO3水分散液代替部分水,采用原位法直接对聚氨酯脲预聚体进行分散,从而得到高固含量(25%-30%)的有机-无机杂化材料。该杂化材料在室温时具有很好的稳定性,且高固含量使其具有节...  相似文献   

9.
为了制备格列美脲微粉,提高格列美脲片的体外溶出度,采用气流粉碎机制备格列美脲微粉,利用高效液相色谱法测定格列美脲微粉片的体外溶出曲线,并以原研格列美脲片亚莫利为参比制剂,用美国食品和药物管理局(FDA)推荐的相似因子f2法进行溶出曲线的相似性比较。结果表明,微粉的中位粒径d50为1.30μm,粒径范围为0.40~5.85μm,3批片剂溶出曲线的相似因子分别为54.0、57.7、53.6;微粉化可以提高格列美脲片的体外溶出度,其溶出行为与原研参比制剂的相似。  相似文献   

10.
目的:建立葡醛内酯片溶出度的测定方法。方法:以水为溶出介质,50转/分钟,30min时取样,以HPLC法测定,检测波长215rim。结果:葡醛内酯在10.1~80.2mg/L的浓度范围内,线性关系良好,R2=0.9993。平均回收率为100.8%,RSD为1.32%。结论:本方法操作简便,结果准确,能有效控制产品溶出度。  相似文献   

11.
The addition of a surfactanat into a tablet formulation appears to be attractive method of improve the drug release rate. The improved release rate is often associated with the effect of surfactant increasing the hydrophilicity of the dosage form thereby promoting drug dissolution. The findings of this investigation showed tha the presence of surfactant infulenced the tablet disintegration rate, producing a finer dispersion of disintergrated particles. It follows that the action of surfactant improving drug dissolution from tablets may be attributed ot the aciton of surfactnat producing fine disintegrated particles with correspondingly larger surface area for drug dissolution. It was also demonstrated that upon tablet disintergration the disinstegrated particles have a tri-moal frequency distribution.  相似文献   

12.
Solid dispersion systems have been widely used to enhance dissolution rate and oral bioavailability of poorly water-soluble drugs. However, the formulation process development and scale-up present a number of difficulties which has greatly limited their commercial applications. In this study, solid dispersions (SDs) of desloratadine (DSL) with povidone (PVP) and crospovidone (cPVP) were prepared by spray coating technique. The process involved the spray application of 96% ethanol solution of DSL and PVP/cPVP, and subsequent deposition of the coprecipitates onto microcrystalline cellulose pellets during drying by air flow in a mini spray coater. The results from the present study demonstrated that the spray coating process is efficient in preparing SDs with enhanced drug dissolution rate and it is highly efficient in organic solvent removal. Both PVP and cPVP greatly improved drug dissolution rate by SDs, with PVP showing better solubilization capability. Very fast drug dissolution rate is achieved from SDs containing PVP regardless of differences in K grade. SD with smaller particles of cPVP have higher drug dissolution rate in comparison to the cPVP with larger particles. Results from physical state characterization indicate that DSL in SDs exist in the amorphous (high free-energy) state which is probably stabilized by PVP/cPVP. After 6-month accelerated stability study, DSL remains amorphous, while PVP and cPVP act as anti-plasticizing agents, offering efficient steric hindrance for nucleation and crystal growth.  相似文献   

13.
Abstract

The addition of a surfactanat into a tablet formulation appears to be attractive method of improve the drug release rate. The improved release rate is often associated with the effect of surfactant increasing the hydrophilicity of the dosage form thereby promoting drug dissolution. The findings of this investigation showed tha the presence of surfactant infulenced the tablet disintegration rate, producing a finer dispersion of disintergrated particles. It follows that the action of surfactant improving drug dissolution from tablets may be attributed ot the aciton of surfactnat producing fine disintegrated particles with correspondingly larger surface area for drug dissolution. It was also demonstrated that upon tablet disintergration the disinstegrated particles have a tri-moal frequency distribution.  相似文献   

14.
The effect of super-paramagnetism is limited to magnetite particles at the nano scale [1–5]. Agglomerated particles exceeding a diameter of 20 nm do not show super-paramagnetism any longer. To transfer this special nano property to a bulk material it is necessary to ensure maximum dispersion of the fine particles within the polymer matrix. The focus of this paper is on the production process for super-paramagnetic magnetite PMMA nano composite material. The polymer PMMA is highly filled up to 50 mass-% with magnetite particles. The solution process uses a stabilized magnetic fluid, in which the polymer is dissolved. This solution/dispersion is atomized and dried in a spray tower to produce a fine powder of composite material. This powder is characterized (SAXS, XRD, VSM, AGM) and further processed e.g. in an injection moulding machine to manufacture structural parts. The structural parts still show super-paramagnetic properties.  相似文献   

15.
Objectives: This study employed electrospray deposition (ESD) for simultaneous synthesis and particle engineering of cocrystals.

Significance: Exploring new methods for the efficient production of cocrystals with desired particle properties is an essential demand.

Methods: The possibility of cocrystal formation by ESD was examined for indomethacin-saccharin, indomethacin-nicotinamide, naproxen-nicotinamide, and naproxen-iso-nicotinamide cocrystals. Solutions of the drug and coformer at stoichiometric ratios were sprayed to a high electric field which caused rapid evaporation of the solvent and the formation of fine particles. The phase purity, size, and morphology of products were compared with reference cocrystals. Experiments were performed to evaluate the effects of stoichiometric ratio, concentration and solvent type on the cocrystal formation. Physical stability and dissolution properties of the electrosprayed cocrystals were also compared with reference cocrystals.

Results: ESD was found to be an efficient and rapid method to produce cocrystals for all studied systems other than indomethacin-nicotinamide. Pure cocrystals only formed at a specific drug:coformer ratio. The solvent type has a weak effect on the cocrystal formation and morphology. Electrosprayed cocrystals exhibited nano to micrometer sizes with distinct morphologies with comparable physical stability with reference cocrystals. Nanococrystals of indomethacin-saccharin with a mean size of 219?nm displayed a threefold higher dissolution rate than solvent evaporated cocrystal.

Conclusion: ESD successfully was utilized to produce pure cocrystals of poorly soluble drugs with different morphologies and sizes ranging from nano to micrometer sizes in one step. This study highlighted the usefulness of ESD for simultaneous preparation and particle engineering of pharmaceutical cocrystals.  相似文献   

16.
Gene therapy has been considered a strategy for delivery of therapeutic nucleic acids to a specific site. Calcium phosphates are one gene delivery vector group of interest. However, low transfection efficiency has limited the use of calcium phosphate in gene delivery applications. Present work aims at studying the fabrication of strontium substituted calcium phosphate nanoparticles with improved gene delivery related properties. Strontium substituted calcium phosphate was prepared using a simple sol gel method. X-ray diffraction analysis, Fourier transform infrared spectroscopy, transmission electron microscopy, specific surface area analysis, zeta potential measurement and ion release evaluation were used to characterize the samples. This characterization showed strontium and carbonate co-substituted calcium phosphate which resulted in nano size particles with low crystallinity, high specific surface area, positive surface charge, and a high dissolution rate. These improved properties could increase the DNA concentration on the vector as well as the endosomal escape of the complex that leads to higher transfection efficiency of this novel gene delivery vector.  相似文献   

17.
纳米氧化锌的表面修饰及其机理的研究   总被引:2,自引:0,他引:2  
朱磊  江红  王滨  魏佳  朱红 《无机材料学报》2007,22(2):219-222
采用改进的直接沉淀法制备了Φ10nm氧化锌. 分别用油酸(OA), 山梨醇酐单硬脂酸酯(Span-60), 月桂酸钠(SL)三种表面活性剂修饰纳米氧化锌颗粒. 宏观沉降实验分析了修饰后的纳米氧化锌在液体石蜡中的稳定性, 发现油酸修饰的纳米氧化锌能在液体石蜡有机相中长时间分散而不沉淀, 具有优异的修饰效果, 而山梨醇酐单硬脂酸酯和月桂酸钠则无法长期稳定存在于有机相中; 微观红外光谱分析表明, 油酸与纳米氧化锌以共价键和氢键两种形式结合, 在无机纳米颗粒表面形成单分子膜; 而山梨醇酐单硬脂酸酯和月桂酸钠的修饰则不牢固.  相似文献   

18.
In this paper, composite particles of nano zinc oxide coated with titanium dioxide were prepared and characterized by TEM, XRD, XPS and FT-IR, and the properties of the composite particles for photo catalysis and light absorption were studied. Tetrabutyl titanate (TBT) was hydrolyzed in an alcoholic suspension of nano zinc oxide with diethanolamine (DEA) as an additive, resulting in a film with a thickness of 20–30 nm being coated on the surface of nano zinc oxide, and the composite particles contained ZnTiO3 after drying and calcination. Photocatalysis capabilities of the composite particles for the degradation of phenol in an aqueous solution were greatly improved as compared with nano zinc oxide particles before coating, with pure nano ZnO and nano TiO2 with similar average sizes, or with the mixture of nano ZnO and TiO2 with the similar composition as the composite particles. The light absorption scope of the composite particles was enlarged when compared to nano titanium dioxide with same average size.  相似文献   

19.
选择在低密度聚乙烯(LDPE)中掺杂无机纳米ZnO和蒙脱土(MMT)颗粒,探讨不同形态无机纳米颗粒对LDPE介电性能的影响。利用熔融共混法配合不同冷却方式制备不同结晶形态的纳米ZnO/LDPE和MMT/LDPE复合材料。通过FTIR、偏光显微镜(PLM)、SEM、DSC和热刺激电流(TSC)对试样进行表征,并。研究了纳米ZnO/LDPE和MMT/LDPE复合材料的交流击穿特性,结果表明:掺杂适当质量分数并经表面修饰的无机纳米颗粒可有效的避免其团聚现象,提高纳米ZnO/LDPE和MMT/LDPE复合材料的结晶速率,使结晶结构更完善,同时无机纳米颗粒掺杂使LDPE的陷阱密度和深度均有所增加,载流子入陷在试样内部形成界面"局域态"。经油冷却方式制备的纳米ZnO/LDPE和MMT/LDPE复合材料击穿场强比空气自然冷却分别高13.6%和14.4%,当掺杂纳米粒子质量分数为3wt%时,复合材料击穿场强出现最大值,其中纳米ZnO/LDPE复合材料比MMT/LDPE复合材料的击穿场强值高0.68%;电导率试验结果表明:纳米ZnO/LDPE复合材料电导率比MMT/LDPE复合材料低。介电性能测试表明,在1~105 Hz的测试频率范围内,纳米ZnO/LDPE复合材料和MMT/LDPE复合材料介电常数降低,介质损耗角正切值有所提高。  相似文献   

20.
The objectives of this paper are to examine the effect of nano particles on the bubble type absorption by experiment and to find the optimal conditions to design highly effective compact absorber for NH3/H2O absorption system. The initial concentrations of NH3/H2O solution and the kinds and the concentrations of nano particles are considered as key parameters. The results show that the addition of nano particles enhances the absorption performance up to 3.21 times. Moreover, the absorption rate increases with increasing concentration of nano particles and the nano particles are more effective for lower absorption potential solution. The potential enhancement mechanism for binary nanofluid is suggested. The experimental correlations of the effective absorption ratio for each nano particles, Cu, CuO, and Al2O3, are suggested within ±10% error-band.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号