反应结晶法制备琥珀酸舒马普坦干粉吸入剂及其评价

在四氢呋喃体系中以舒马普坦(碱)和丁二酸为反应物,采用反应结晶法制备琥珀酸舒马普坦干粉吸入剂.对影响产物粒径和形貌的因素,如反应物的配比、反应温度、搅拌速度等进行了考察,并对最优条件下所得的干粉进行了相关的物化性质表征.结果表明,当反应物的配比nST:n丁二酸为1:2、反应温度范围为0～15℃、搅拌速度为10000 r/min时,可以得到平均粒径大约为1 μm、且粒度分布窄的琥珀酸舒马普坦颗粒,其体外沉积实验结果明显优于现有市售琥珀酸舒马普坦产品,肺部沉积值大约提高了5倍.     

超声机械法制备纳米二氧化硅及影响因素分析

引言 20世纪,人们发现了纳米粒子具有传统常规颗粒材料所不具备的优良的理化性质和特殊的光、电、磁等特性,从而开始了对纳米粒子的研究,其中包括对纳米粉体粒子基本制备方法的探索[1].纳米粉体粒子的制备方法可以归结为两大类:一类是粉碎法,即将宏观物体逐步细化得到纳米颗粒;另一类是构筑法,即从原子、离子或分子出发,通过成核和长大两个阶段来构筑纳米粒子[2].构筑法制备纳米粉体粒子所用的能量主要为热能和化学能,需要较高的温度,消耗较高能量,后续的除杂工艺较为繁杂,生产过程中还有可能造成环境污染等.而粉碎法制备纳米粉体粒子,设备投资少、能耗低、效率高、生产能力大、生产过程和产品性能易于控制.     

机械粉碎法制备纳米HMX及其机械感度研究

采用机械粉碎法制备了纳米HMX,用纳米激光粒度仪和场发射扫描电子显微镜(FESEM)对其粒度分布、颗粒的大小和形貌进行了表征,测试了原料HMX和纳米HMX的摩擦感度、撞击感度和冲击波感度.结果表明,制备的HMX粒径基本小于100 nm;与原料HMX相比,纳米HMX的摩擦感度有较大幅度降低,撞击感度和冲击波感度分别降低107.0％和62.1％,安全性明显提高.     

硬脂酸修饰纳米氧化钇的制备及其亲油特性

引 言 氧化钇独特的4f电子层结构[1-2],使其具有了诸多的优良性能.在催化、陶瓷、光学玻璃、荧光、涂料等领域得到了广泛的应用[3-4].作为润滑油添加剂,其抗磨减摩效果明显,抗磨润滑性能卓越,潜在发展空间较大[5].纳米化后的氧化钇具有更多的新性能,然而,纳米氧化钇颗粒的粒径小、比表面积大、表面活性高、容易团聚使得纳米氧化钇的应用受到一定的局限[6].     

水性聚氨酯涂层胶复配凝胶问题探究

探索水性聚氨酯涂层胶复配凝胶的影响因素。从乳液粒径及其分布、Zeta电位、pH值以及电导率等方面进行了考察,确定了样品中大颗粒粒子体积含量和样品平均粒径大小为主要影响因素,其中大颗粒粒子体积含量对凝胶程度影响最为显著,并通过合成不同粒径大小和分布的样品加以验证。     

共沉淀法与水热法制备磁性四氧化三铁纳米颗粒的比较研究

本实验通过共沉淀法和水热法制备并表征四氧化三铁磁性纳米颗粒。考察了不同方法对生成物的影响作用。结果显示,两种制备方法到的产物均为反尖晶石结构,结晶度高;共沉淀法得到的Fe_3O_4纳米颗粒主要为大小较均匀的球形结构,纳米颗粒粒径约为12~15 nm,产物团聚现象较为明显;水热法制备的Fe_3O_4纳米颗粒为准球形状,粒径分布均匀,与共沉淀法合成Fe_3O_4纳米颗粒相比,水热法合成的Fe_3O_4纳米颗粒粒径明显增大,约到20 nm左右,团聚现象有缓解。     

扁平式气流粉碎机超微粉碎布洛芬的工艺研究

采用扁平式气流粉碎技术进行了布洛芬微粉化试验研究,考察了工质压力、进样速度、布洛芬原料粒度及分布等对布洛芬微粉颗粒大小和粒径分布的影响.实验结果表明采用扁平式气流粉碎技术进行超细粉碎,可使布洛芬微粉平均粒径达到6μm,达到制备布洛芬缓释胶囊的要求.     

纳米硫酸钡的制备及表征

以硫酸钠和碳酸钡为原料,碳酸钡经过浆化处理后,与硫酸钠直接反应制备纳米硫酸钡。实验考察了浆化溶剂用量对纳米硫酸钡粒度的影响,随着浆化溶剂用量的增加,纳米硫酸钡的产率提高,颗粒分布更均匀,粒径更小。经SEM和XRD测试分析,计算得出粒子的平均粒径为20nm左右。结果表明,该法可以制备出粒径小、分布窄的纳米硫酸钡粒子。     

纳米金溶胶的合成及紫外-可见吸收光谱的研究

在弱酸性或近中性条件下,用化学还原剂还原较高浓度的氯金酸溶液,制得纳米金种子溶液,然后用晶种法制备金溶胶。通过透射电镜、激光粒度分布仪等测定了纳米颗粒的粒径和分布情况,并对纳米金溶胶的紫外可见吸收曲线进行了研究。结果表明,以硼氢化钠为还原剂可以得到粒径小且分布均匀的产品,采用不同大小的晶种制备的纳米金颗粒的粒径不同,且随粒径变大紫外-可见吸收曲线上的最大吸收波长红移也越大,分布变宽。     

共沉淀法制备纳米Fe3O4影响因素的研究

利用正交设计的数学方法进行实验设计,采用液相共沉淀法制备纳米级Fe3O4颗粒,考察不同影响因素对微球平均粒径大小的影响,寻找制备纳米颗粒的最佳条件.所考察的因素分别为胶溶化时HCl加入量、Fe3+与Fe2+的比例、共沉淀时的pH值、制备Fe3O4的晶化温度.结果表明,以胶溶化时加入HCl3mL、Fe3+与Fe2+的比例2:3、共沉淀时的pH值11和制备Fe3O4的晶化温度80℃为最佳实验条件为,此时制得的纳米粉体平均粒径可达16.3nm;并利用粒径分析仪和HRTEM对所制备纳米粉进行结构表征.     

Preparation and Physicochemical Properties of Vinblastine Microparticles by Supercritical Antisolvent Process

The objective of the study was to prepare vinblastine microparticles by supercritical antisolvent process using N-methyl-2-pyrrolidone as solvent and carbon dioxide as antisolvent and evaluate its physicochemical properties. The effects of four process variables, pressure, temperature, drug concentration and drug solution flow rate, on drug particle formation during the supercritical antisolvent process, were investigated. Particles with a mean particle size of 121 ± 5.3 nm were obtained under the optimized process conditions (precipitation temperature 60 °C, precipitation pressure 25 MPa, vinblastine concentration 2.50 mg/mL and vinblastine solution flow rate 6.7 mL/min). The vinblastine was characterized by scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, mass spectrometry and dissolution test. It was concluded that physicochemical properties of crystalline vinblastine could be improved by physical modification, such as particle size reduction and generation of amorphous state using the supercritical antisolvent process. Furthermore, the supercritical antisolvent process was a powerful methodology for improving the physicochemical properties of vinblastine.     

Synthesis of 5-Fluorouracil nanoparticles via supercritical gas antisolvent process

The micronization of an anticancer compound (5-Fluorouracil) by supercritical gas antisolvent (GAS) process was investigated. 5-Fluorouracil was dissolved in dimethyl sulfoxide (DMSO) and subsequently carbon dioxide as an antisolvent was injected into this solution thus, the solution was supersaturated and nanoparticles were precipitated. The influence of antisolvent flow rate (1.6, 2 and 2.4 mL/min), temperature (34, 40 and 46), solute concentration (20, 60 and 100 mg/mL) and pressure (9, 12 and 15 MPa) on particle size and particle size distribution were studied. Particle analyses were performed by scanning electron microscopy (SEM) and Zetasizer Nano ZS. The mean particle size of 5-Fluorouracil was obtained in the range of 260–600 nm by varying the GAS effective parameters. The High performance liquid chromatography (HPLC) and Fourier transforms infrared spectroscopy (FTIR) analyses indicated that the 5-Fluorouracil nanoparticles were pure and the nature of the component did not change. The experimental results indicated that increasing the antisolvent flow rate and pressure, while decreasing the temperature and initial solute concentration, led to a decrease in 5-Fluorouracil particle size.     

Formation of biodegradable polymeric fine particles by supercritical antisolvent precipitation process

The supercritical antisolvent (SAS) precipitation process as a “green” alternative to specialty particles recrystallization was successfully used to generate poly(L ‐lactide) acid (L‐PLA) from dichloromethane (DCM) solution using CO₂ as antisolvent. The influence of main operating parameters on the synthesis of L‐PLA particles in the SAS process was methodically examined. In particular, antisolvent addition rate (30, 40, 50, and 60 g/min), temperature (35, 40°C, 45°C, and 50°C), solute concentration (50, 75, 100, and 150 mg/10 ml), and solution addition rate (1, 2.5, 5, and 7.5 ml/min). These parameters could be tuned to give a mean particle diameter of 0.62 μm. It was found using scanning electron microscopy and laser diffraction that increasing the antisolvent addition rate and the solution addition rate, while decreasing the temperature and solute concentration, led to a decrease in the L‐PLA mean particle diameter. Furthermore, a unimodal particle size distribution was obtained at the higher solution and antisolvent addition rates. Spherical‐like primary particles have been obtained in all the experimental runs; thus, no change of particle morphology with the process parameters has been noticed. These results manifested that SAS recrystallization process is a valuable technique to generate reproducibly polymer particles with controlled size and size distribution. POLYM. ENG. SCI. 2013. © 2012 Society of Plastics Engineers     

New Insights into Acrylic Polymer Precipitation by Supercritical Fluids

Nanosystems based on polymers have attracted much attention due to the almost infinite diversity. In the past decades, the application of supercritical fluids for polymeric particle precipitation has been developed as an alternative to conventional processes. Here, precipitation of an acrylic copolymer was attempted by the rapid expansion of supercritical solutions (RESS) and successful by supercritical antisolvent (SAS) processes. In addition, the nanoparticles were characterized with different techniques. The polymer concentration, pressure, temperature, liquid solution flow rate and nozzle diameter effects were also evaluated with regard to particle size and the particle size distribution of this polymer.     

Micronization of taxifolin by supercritical antisolvent process and evaluation of radical scavenging activity

The aim of this study was to prepare micronized taxifolin powder using the supercritical antisolvent precipitation process to improve the dissolution rate of taxifolin. Ethanol was used as solvent and carbon dioxide was used as an antisolvent. The effects of process parameters, such as temperature (35-65 °C), pressure (10-25 MPa), solution flow rate (3-6 mL/min) and concentration of the liquid solution (5-20 mg/mL) on the precipitate crystals were investigated. With a lower temperature, a stronger pressure and a lower concentration of the liquid solution, the size of crystals decreased. The precipitation temperature, pressure and concentration of taxifolin solution had a significant effect. However, the solution flow rate had a negligible effect. It was concluded that the physicochemical properties and dissolution rate of crystalline taxifolin could be improved by physical modification such as particle size reduction using the supercritical antisolvent (SAS) process. Further, the SAS process was a powerful methodology for improving the physicochemical properties and radical scavenging activity of taxifolin.     

反溶剂沉淀法制备阿托伐他汀钙微粉

采用反溶剂沉淀法制备阿托伐他汀钙微粉,考察了表面活性剂类型、药物溶液浓度、体系温度和干燥方法对颗粒形貌和大小的影响,得到了适宜的微粉化条件。实验分别利用扫描电镜（SEM）、X射线衍射（XRD）、红外光谱分析（FT-IR）和比表面积（BET）等分析方法对原料及产品的性质进行了表征。研究结果表明：表面活性剂甲基纤维素（MC₂₀）可以有效地控制颗粒形貌;改变溶液浓度及体系温度可以调整颗粒大小;混悬液经喷雾干燥得到的干粉是粒度分布均匀的团粒状类球形颗粒,粒径约为1 μm。微粉化产品为无定形,比表面积高于原料药。此外,还探讨了团粒状类球形颗粒的形成机理。     

Preparation and Physicochemical Properties of 10-Hydroxycamptothecin (HCPT) Nanoparticles by Supercritical Antisolvent (SAS) Process

The goal of the present work was to study the feasibility of 10-hydroxycamptothecin (HCPT) nanoparticle preparation using supercritical antisolvent (SAS) precipitation. The influences of various experimental factors on the mean particle size (MPS) of HCPT nanoparticles were investigated. The optimum micronization conditions are determined as follows: HCPT solution concentration 0.5 mg/mL, the flow rate ratio of CO(2) and HCPT solution 19.55, precipitation temperature 35 °C and precipitation pressure 20 MPa. Under the optimum conditions, HCPT nanoparticles with a MPS of 180 ± 20.3 nm were obtained. Moreover, the HCPT nanoparticles obtained were characterized by Scanning electron microscopy, Dynamic light scattering, Fourier-transform infrared spectroscopy, High performance liquid chromatography-mass spectrometry, X-ray diffraction and Differential scanning calorimetry analyses. The physicochemical characterization results showed that the SAS process had not induced degradation of HCPT. Finally, the dissolution rates of HCPT nanoparticles were investigated and the results proved that there is a significant increase in dissolution rate compared to unprocessed HCPT.     

Supercritical CO2 precipitation of poly(l-lactic acid) in a wide range of miscibility

Polymer microparticles are useful for numerous applications such as stationary phases in chromatography, adsorbents and catalyst supports, as well as for drug delivery systems. In recent decades the application of supercritical fluids for microparticle precipitation has been developed to a point where it is an ideal alternative to conventional processes. In this work poly(l-lactic acid) (PLLA), a biodegradable and biocompatible thermoplastic aliphatic polyester, has been processed using supercritical fluids, particularly by rapid expansion of supercritical solutions (RESS) and supercritical antisolvent (SAS) processes over a wide miscibility range. Particle morphology was greatly improved from irregular blocks to spherical microparticles on applying the SAS process. The effects of changes in polymer concentration, liquid flow rate, nozzle diameter, solvent, pressure and temperature have also been evaluated on the particle size of PLLA in the SAS precipitation. A higher concentration of the initial solution led to a decrease in particle size. Dichloromethane was the best of the chlorinated solvents investigated. The nozzle diameter had a negligible effect on particle size and the highest liquid flow rate gave the largest particle size. A larger particle size was also obtained on increasing the operating temperature. In contrast, the particle size decreased on increasing the operating pressure.     

Antisolvent crystallization of carbamazepine from organic solutions

Carbamazepine was crystallized from organic solutions using an antisolvent crystallization technique. Ethanol was used as a solvent for the carbamazepine and distilled water was used as an antisolvent. The carbamazepine was dissolved in the solvent, and the drug solution was injected into the antisolvent causing the particle precipitation. During the crystallization experiments, the effects of the process parameters such as solution concentration, temperature, injection rate of the solution, and the presence of ultrasound, were investigated. An analysis of the produced particles showed that external characteristics such as particle size and its distribution were a strong function of the process parameters, while the internal structures such as crystallinity and thermal stability were nearly unaffected. Smaller particles were obtained when solutions with high drug concentrations were used. Higher temperature resulted in larger crystals. Particle size was also influenced by the injection rate of the drug solutions. Carbamazepine particle size was significantly reduced when the ultrasonic wave was selectively applied.     

Membrane dispersion precipitation method to prepare nanopartials

In this paper, a new method for preparing nanoparticles with membrane dispersion technology was developed by integrating direct chemical precipitation and membrane emulsification. Barium sulfate nanoparticles were prepared with the new method in a membrane dispersion module with a plate microfiltration membrane as dispersion medium. Barium chloride solution and sodium sulfate solution with pure water or 20% ethyl alcohol in water as solvents were selected as the reactants. The influences of the reactant concentrations, two-phase flow rate and membrane pore size were investigated. The morphology of the nanoparticles was characterized by TEM images, and the particle-size distribution was measured. The results showed that the spheric nanoparticles of barium sulfate could be prepared with the new method. The average size was in the range of 20-200 nm. The particles prepared by the new method were much more uniform, compared with those by direct precipitation method. The average size of barium sulfate nanoparticles was decreased with an increase of the concentration and the flow rate of sodium sulfate solution quickly. However, those of barium chloride solution had little influence on barium sulfate nanoparticles. The decreasing of the membrane pore size resulted in the decrease of the average size of barium sulfate nanoparticles. And by changing 20% ethyl alcohol in water as solvent instead of pure water, the nanoparticle size was decreased from 70 to 20 nm.