纳米羟基磷灰石/聚氨酯载药微球的制备及性能

通过乳液聚合法制备了负载阿莫西林的纳米羟基磷灰石/聚氨酯(n-HA/PU)载药微球,通过正交设计实验对其制备工艺进行了优化,采用红外光谱、热重分析、扫描电镜等分析了微球的结构和性能,对其体外药物缓释过程进行探讨。研究结果表明,复合微球粒径大小与固含量、聚乙烯吡咯烷酮(PVP)含量、搅拌速度等有关,所制备的微球平均粒径为0.8~1.2mm;载药微球的优化制备工艺条件为:原料配比-NCO∶-OH=2∶1,预聚时间180min,预聚温度80℃,nHA含量3%,固含量7%,搅拌速度600r/min,PVP用量3%,所制备微球的载药量为6.58%,包封率为86.86%。体外缓释结果表明,载药微球的释药行为符合Higuchi动力学,半衰期(t1/2)为22.29h,具有良好的药物缓释作用。     

LiMn<Subscript>2</Subscript>O<Subscript>4</Subscript> microspheres: Synthesis,characterization and use as a cathode in lithium ion batteries

Solid and hollow microspheres of LiMn₂O₄ have been synthesized by lithiating MnCO₃ solid microspheres and MnO₂ hollow microspheres, respectively. The LiMn₂O₄ solid microspheres and hollow microspheres had a similar size of about 1.5 ?m, and the shell thickness of the hollow microspheres was only 100 nm. When used as a cathode material in lithium ion batteries, the hollow microspheres exhibited better rate capability than the solid microspheres. However, the tap density of the LiMn₂O₄ solid microspheres (1.0 g/cm³) was about four times that of the hollow microspheres (0.27 g/cm³). The results show that controlling the particle size of LiMn₂O₄ is very important in terms of its practical application as a cathode material, and LiMn₂O₄ with moderate particle size may afford acceptable values of both rate capability and tap density.     

微纳分级结构碳酸钙中空微球的可控制备

以CaCl₂和Na₂CO₃为反应原料, 以聚乙烯吡咯烷酮(PVP)和十二烷基磺酸钠(SDSN)为模板剂, 在50℃采用化学沉淀反应, 干燥、煅烧后成功制备了具有微纳分级结构的CaCO₃中空微球。采用扫描电子显微镜、透射电子显微镜和X射线衍射等检测手段对所制备的样品形貌、结构进行了表征, 结果显示：所制备的微纳分级结构CaCO₃中空微球直径为4~6 μm, 壳壁由直径约60 nm的CaCO₃颗粒组成, 壳层厚度约为200 nm, CaCO₃中空微球晶相组成为方解石和球霰石的共混体。同时, 在反应温度为50℃、PVP添加量为0.4 g, SDSN浓度为0.1 mol/L的条件下, 所制备的微纳分级结构CaCO₃中空微球分散性好, 且形貌比较完整。     

Carnauba Wax Microspheres Loaded with Valproic Acid: Preparation and Evaluation of Drug Release

To minimize unwanted toxic effects of valproic acid (1) by the kinetic control of drug release, gastroresistant carnauba wax microspheres loaded with the antiepileptic agent were prepared. The preparation was based on a technique involving melting and dispersion of drug-containing wax in an aqueous medium. The resulting emulsion after cooling under rapid stirring produced solid, discrete, reproducible free flowing microspheres which converted the liquid drug droplets into solid material. About 94% of the isolated microspheres were of particle size range 200-425 μm. The microspheres were analyzed to determine the drug content in various particle size range and to characterize the in vitro release profile. The average drug content was 26% w/w. The intestinal drug discharge of 1 from the carnauba wax microspheres was studied and compared with the release patterns observed for white beeswax and hexadecanol microspheres previously described. The drug release performance was greatly affected by the material used in the microencapsulation process. In the intestinal environment carnauba wax microspheres exhibited more rapid initial rate of release and about 80% of the entrapped drug was discharged in 120 min while complete release occurred in about 8 h.     

分级介孔结构组成的ZnO微球及光催化性能

以硝酸锌、脲素及酒石酸为反应物, 采用水热法制备碱式碳酸锌前驱体微球, 通过煅烧前驱体制备了介孔氧化锌微球。通过扫描电子显微镜(SEM)可以观察到, 氧化锌微球的直径约为2~4 μm, 由大量厚度约为10 nm的介孔纳米片组装而成。X 射线衍射(XRD)和透射电镜(TEM)结果表明: ZnO微球为六方纤锌矿结构, 并结晶较好。比表面积测试(BET)表明ZnO微球为介孔材料, 孔径为20~50 nm, ZnO微球比表面积约为29.8 m²/g。以亚甲基蓝为目标降解物, 对介孔氧化锌微球进行了光催化降解实验。实验结果表明, 所合成的介孔ZnO微球对亚甲基蓝的光催化性能较好。     

Hollow Alumina Microspheres From Boehmite Sols

Hollow alumina microspheres were obtained from emulsified boehmite sols by an ion extraction method. The viscosity and the equivalent alumina content of the sols were found to affect the characteristics of the derived microspheres. High-viscosity sols produced broken microspheres. A temperature of about 400–500 °C for boehmite to -Al2O3 transformation in the gel microspheres was observed by differential thermal analysis and X-ray diffraction. Complete crystallization of the gel microspheres to -Al2O3 occurred at 1200 °C. A tentative mechanism for the formation of the hollow microspheres is presented.     

聚（N-异丙基丙烯酰胺-co-丙烯酸）/Fe3O4复合微球的制备及表征

采用Fe3O4、N-异丙基丙烯酰胺(NIPAM)和丙烯酸(AA)制备了具有磁敏、温敏和pH敏感的多重敏性复合微球。先使用共沉淀法制备Fe3O4磁性纳米颗粒,并用油酸对其改性。继而采用种子聚合法制备P(NIPAM-co-AA)磁性微球。研究表明,在pH值为10的合成条件下,复合微球的分散性较好。采用疏水性引发剂可相对增加有机、无机相之间的亲和性。通过扫描电镜(SEM)、红外光谱(FT-IR)、动态光散射(DLS)和超导量子干涉磁强计(SQUID)等对微球进行了结构与形态表征,结果证明,复合微球形貌统一,各组分之间聚合良好。复合微球的粒径约为249 nm,对温度、pH可作出预期的响应,饱和磁化强度为40 emu/g。     

Carnauba Wax Microspheres Loaded with Valproic Acid: Preparation and Evaluation of Drug Release

Abstract

To minimize unwanted toxic effects of valproic acid (1) by the kinetic control of drug release, gastroresistant carnauba wax microspheres loaded with the antiepileptic agent were prepared. The preparation was based on a technique involving melting and dispersion of drug-containing wax in an aqueous medium. The resulting emulsion after cooling under rapid stirring produced solid, discrete, reproducible free flowing microspheres which converted the liquid drug droplets into solid material. About 94% of the isolated microspheres were of particle size range 200-425 μm. The microspheres were analyzed to determine the drug content in various particle size range and to characterize the in vitro release profile. The average drug content was 26% w/w. The intestinal drug discharge of 1 from the carnauba wax microspheres was studied and compared with the release patterns observed for white beeswax and hexadecanol microspheres previously described. The drug release performance was greatly affected by the material used in the microencapsulation process. In the intestinal environment carnauba wax microspheres exhibited more rapid initial rate of release and about 80% of the entrapped drug was discharged in 120 min while complete release occurred in about 8 h.     

A novel method for the synthesis of polyamide 6 magnetic microspheres

Polyamide 6 (PA6) magnetic microspheres were firstly prepared via successively in situ polymerization using phase inversion technology of polymer pairs polyamide 6/polystyrene (PA6/PS) at extremely low PS content. The properties of PA6 magnetic microspheres, such as morphologies, diameter size distribution, magnetic properties, thermal stability, and the functional groups of the magnetic microspheres, were investigated by different techniques (i.e. SEM, TEM, DLS, VSM, FTIR, and DSC). The results indicated that the diameter distribution of PA6 magnetic microspheres was narrow, and the mean diameter size was about 7.7 μm. The saturation magnetization of magnetic microspheres reached 12.50 emu/g. Furthermore, the magnetic microspheres had abundant functional groups and better thermal stability.     

羧基化聚苯乙烯微球的制备及其自组装行为研究

采用分散聚合法,以乙醇、水为分散介质,苯乙烯为共聚单体,聚乙烯吡咯烷酮（PVP）为稳定剂,AIBN为引发剂,丙烯酸（AA）为功能共聚单体,制备了粒径为100—1000nm羧基化聚苯乙烯微球,研究醇水比、分散剂、引发剂用量对微球粒径及分布的影响,分析微球表面形貌、粒径分布、表面羧基含量,结果表明,胶体晶体是面心立方密排结构,微球单分散性好,表面光滑,球形度好,表面羧基含量最高可达到0．206mmol／g。同时,用垂直沉积法制备出较大范围内呈现高度有序的密排结构聚苯乙烯胶体晶体。     

单分散聚硅氧烷微球的制备表征及作为光散射剂的应用

以乳液聚合法制备粒径分布均匀、球形度良好的聚硅氧烷微球。采用扫描电镜(SEM)、动态光散射(DLS)、红外光谱(FT-IR)、X射线衍射(XRD)、热重分析(TGA)和接触角等测试技术对微球的微观形貌、粒径大小及分布、聚集态结构、耐热性、疏水性等进行了表征。将平均粒径为1.5μm的聚硅氧烷微球作为光散射剂添加到光学级聚甲基丙烯酸甲酯(PMMA)树脂中,可制备出性能优良的光散射材料。当聚硅氧烷微球添加质量分数约0.6%时,光散射材料的透光率是86.1%,雾度是91.25%,拉伸强度达到最大值77.2 MPa,弯曲强度是87.2 MPa,简支梁缺口冲击强度是2.16 kJ/m2,悬臂梁缺口冲击强度是2.71 kJ/m2,综合性能良好。     

Fabrication and characterization of porous hydroxyapatite microspheres by spray-drying method

In the present paper, porous hydroxyapatite (HA) microspheres were fabricated using gelatin as a pore-forming agent by spray-drying method. The mean particle size of the microspheres is about 7 μm and the surface area is about 53.4 m²/g. The experimental results showed that the porosity of the prepared microspheres is higher and the pores are more interconnected compared with the microspheres obtained without any additives.     

A novel solid-stabilized emulsion approach to CuO nanostructured microspheres

Nanostructured CuO microspheres were prepared by a novel solid-stabilized emulsion for the first time. SEM, TEM, XRD, size analysis and BET measurement were used to characterize the CuO microspheres. The average diameter of the CuO microspheres was 2.8 μm. The surfaces of the CuO microspheres were made of pin-like nanostructures with a pin diameter of 95 nm and a pin length of at least 600 nm. The XRD analysis indicated that the CuO nanostructured microspheres were of monoclinic lattice. The specific surface area of the CuO nanostructured microspheres was about 56.8 m²/g. A mechanism for the formation of the CuO microspheres with nanostructured surfaces was proposed.     

Gd_2O_3空心微球的制备及Gd_2O_3/丁基橡胶复合材料低频阻尼性能

以分散聚合法制备的聚苯乙烯(PS)微球作为模板,通过均相沉淀法制备前驱体PS-Gd(OH)CO_3复合微球,高温煅烧后得到Gd_2O_3空心微球,将其与丁基橡胶复合制备低频高阻尼Gd_2O_3/丁基橡胶复合材料。采用FTIR、SEM、TEM分析、TG分析仪、XRD分析和XPS对Gd_2O_3空心微球的形貌与结构组成进行表征。将Gd_2O_3空心微球与粉体分别作为填料加入丁基橡胶中制备Gd_2O_3/丁基橡胶复合材料。结果表明:Gd_2O_3空心微球由立方萤石结构的颗粒组成,外空心直径为0.9μm,壳层厚度约为100nm;添加空心微球的复合材料阻尼性能较好;与纯丁基橡胶相比,Gd_2O_3/丁基橡胶复合材料的低频阻尼性能明显提高。     

PLLA-PEG-PLLA/Fe_3O_4磁性微球的制备及性能

以聚乙二醇为引发剂,L-丙交酯为单体,开环聚合得到聚乳酸-聚乙二醇三嵌段共聚物(PLLA-PEG-PLLA),采用溶剂挥发法制备了PLLA-PEG-PLLA/Fe_3O_4磁性微球,并通过扫描电镜对其形态进行了表征。利用振动样品磁强计和Tg研究了微球的磁含量和磁性能,结果发现,相同粒径不同磁含量的磁性微球,磁含量越高,升温速率越快,当磁含量为70.57%时,升温速率最快,能达到磁热疗的有效温度42℃。对于磁含量相同,粒径不同的微粒,粒径越小,升温速率越快,粒径约为10μm时升温速率最快。     

Si02气凝胶微球的制备及表征

以正硅酸乙酯（TEOS）为先驱体制备硅溶胶,再以硅油为分散介质,在吐温80为乳化剂的油相与SiO2溶胶为水相的乳化体系中,应用雾化法和乳液成球技术制备微米级SiO2凝胶小球,然后,通过超临界CO2干燥技术制备微米级siO2气凝胶小球,用光学显微镜、SEM、红外光谱（FT—IR）及cBET技术对其表征,结果表明,微米及SiO2气凝胶小球表观粒径较为均匀,平均粒径约为30μm,密度为216kg／m2,平均孔径6．72nm,BET比表面积为802．35m2／g,孔体积为1．15cm3／g,是一种具有典型气凝胶结构的微粒状轻质纳米多孔材料。     

MgO nanostructured microspheres synthesized by an interfacial reaction in a solid-stabilized emulsion

Nanostructured MgO microspheres were prepared by a novel solid-stabilized emulsion for the first time. SEM, XRD, size analysis and BET measurement were used to characterize the MgO microspheres. The diameter of the MgO microspheres was in a range of 5.1 to 5.4 μm. The surfaces of the MgO microspheres were made of leaf-like nanostructures with a leaf thickness of 65 nm. The XRD analysis indicated that the MgO nanostructured microspheres were of cubic lattice. The specific surface area of the MgO nanostructured microspheres was about 105.8 m²/g. The MgO microspheres with nanostructured surfaces had a larger specific surface area than the MgO polyhedral particles prepared by the comparing experiment (via a conventional homogeneous precipitation route). An interfacial reaction mechanism for the formation of the MgO microspheres with nanostructured surfaces was proposed.     

葡萄糖基炭微球的制备与结构表征

以葡萄糖为碳源制备炭微球,考察了原料浓度、反应时间和反应温度对所得炭微球形貌和产率的影响,并测定了其表面官能团的种类和数量。结果表明,葡萄糖浓度为0．5mol／L、反应温度为180℃、反应时间为7h的条件下制备了粒径300nm左右、分数性较好的炭微球。所得炭微球表面合有丰富的羟基、羰基、羧基等含氧官能团,采用联碱中和法定量测定了上述官能团的含量。     

Enhanced oral bioavailability of piroxicam in rats by hyaluronate microspheres

To enhance the dissolution and oral bioavailability of poorly water soluble piroxicam, the piroxicam-loaded hyaluronic microspheres were prepared with various ratios of piroxicam, sodium hyaluronate and polyethylene glycol 4000 (PEG) using a spray dryer, and their physicochemical properties such as shape, size, drug-loading efficiency and dissolution were investigated. The pharmacokinetic study of piroxicam-loaded hyaluronic micropheres in rats was then performed compared to piroxicam powder. The piroxicam-loaded hyaluronic microspheres, spherical in shape, had the geometric mean diameters of about 1.5 μm and drug loading efficiency of about 90%, irrespective of ratio of piroxicam/sodium hyaluronate/PEG. The hyaluronic microspheres containing PEG gave significantly higher dissolution rates of drug than did piroxicam powder, PEG-based solid dispersion system and hyaluronic microspheres without PEG, suggesting that the hyaluronic microsphere with sodium hyaluronate and PEG was more useful for improving the dissolution rate of poorly water soluble piroxicam. The piroxicam-loaded hyaluronic microcapsule composed of (piroxicam/sodium hyaluronate/PEG; 2: 20: 1) gave about threefold improved dissolution of drug in water for 4 h compared to piroxicam powder. It showed higher plasma concentrations of drug compared to piroxicam powder. It gave significantly higher AUC and faster T_max of piroxicam than did piroxicam powder. In particular, the AUC of piroxicam from hyaluronic microsphere was about twofold higher than that from piroxicam powder, suggesting that it could enhance the oral bioavailability of piroxicam. Thus, the hyaluronic microsphere developed using spray-drying technique with sodium hyaluronate and PEG was a more effective oral dosage form for poorly water soluble piroxicam.     

Hollow MCM-41 microspheres derived from P(St-MMA)/MCM-41 core/shell composite particles

In soap-free latex media, poly(styrene-methyl methacrylate)/MCM-41 core/shell composite microspheres have been fabricated by adding silicate source in batches. In this process, silicate species and the surfactant micelles were self-assembled into 2-dimensional hexagonal arrangement on the surface of P(St-MMA) microspheres. Hollow MCM-41 microspheres were obtained via removing polymer core by solvent. XRD, TEM, IR and N₂ adsorption-desorption analysis were applied to characterize products. The results showed that average diameter and wall thickness of hollow MCM-41 microspheres is about 240 nm and 20 nm, respectively. Results of N₂ adsorption-desorption indicate that hollow MCM-41 microspheres possess a highly ordered mesoporous structure and a narrow pore distribution with a mean value of 2.34 nm.