pH-independent dissolution enhancement for multiple poorly water-soluble drugs by nano-sized solid dispersions based on hydrophobic–hydrophilic conjugates

The objective of this study was to achieve an optimal formulation of hydrophilic–hydrophobic conjugates for nano-sized solid dispersions (SDs) with enhanced dissolution of multiple drugs in different gastrointestinal (GI) tract environments. A new conjugate powder with an optimized process was used to fabricate SDs that contained three poorly water-soluble drugs that were also poorly soluble in different dissolution media. The self-assembled nanoparticle formation, drug crystallinity and SD molecular interactions were investigated by measuring the particle size during dissolution testing and physicochemical property analysis (powder X-ray diffraction and Fourier transform infrared spectroscopy). Drug release studies indicated that SD containing conjugated powder significantly improved the dissolution rates of these poorly water-soluble drugs in the GI tract. In addition, particle size analysis showed nano-sized particles in the dissolution media in the early stage with a tendency to reduce smaller particles over time. Physicochemical characterizations demonstrated almost amorphous drug states and hydrogen bonding interactions between the drugs and conjugates in the SD. This study optimized a promising material for SD, and the material was shown to have a promising performance under various pH medium conditions with poorly water-soluble drugs.     

改性纳米碳酸钙用于硅酮胶挤出性研究

采用碳化法合成纳米碳酸钙,在反应过程中,调整反应起始温度合成不同晶型大小的纳米碳酸钙。通过透射电镜（TEM）、激光粒度仪对碳酸钙的物相、形貌、粒度进行分析,将改性纳米碳酸钙应用于硅酮胶基料制备及挤出性研究,分析改性纳米碳酸钙的颗粒大小、分散性、流变性能及表面改性剂对挤出性的影响。结果表明：粒径介于50~90 nm,屈服值介于66.4~148.9 Pa,黏度介于0.5~0.75 mPa·s,硬脂酸钠与LH-2、LH-3两种包覆剂进行复配改性的纳米碳酸钙用于硅酮胶基料具有较好的挤出性能。     

不同形貌纳米二硫化钼制备研究进展

纳米二硫化钼由于具有层状结构、大的比表面积和稳定的伏安特性,在摩擦、催化、电极材料等领域有着广泛的应用前景。对不同形貌纳米二硫化钼的制备研究现状进行总结归纳,比较分析富勒烯、球状、管状等纳米结构二硫化钼的制备方法和形成机理,并展望纳米二硫化钼的研究发展趋势。     

液相化学还原法制备纳米银颗粒的研究

采用液相还原法,以PVP为分散剂,甲酸铵为还原剂,在30℃ AgNO3溶液高速搅拌下制备得到纳米银颗粒。采用X射线衍射（XRD）、透射电子显微镜（TEM）和紫外-可见光吸收光谱（UV-Vis）对所制备样品进行表征。当PVP 与AgNO3的质量比为2.2∶1,陈化时间24 h,得到立方块和六棱柱的银混合颗粒。     

Product distribution and catalytic performance of nano-sized H-ZSM-5 zeolites in the methanol-to-aromatics (MTA) reaction

A study of the effect of SiO₂/Al₂O₃ molar ratio on the activity and selectivity of H-ZSM-5 catalyst in the reaction of methanol to aromatics (MTA) has been carried out in this work. Aluminosilicate zeolite (ZSM-5) zeolites with different SiO₂/Al₂O₃ molar ratios were successfully synthesized by the hydrothermal method. The SiO₂/Al₂O₃ molar ratio of the prepared ZSM-5 zeolite particles could be easily controlled by changing the ratio of tetraethylorthosilicate to aluminum nitrate nonahydrate. The effect of SiO₂/Al₂O₃ molar ratio on the activity of nano-sized H-ZSM-5 zeolites in the MTA reaction was studied. The H-ZSM-5 zeolite catalyst with low SiO₂/Al₂O₃ molar ratios shows remarkable selectivity toward aromatics and benzene, toluene, and xylene (BTX) in the MTA reaction.     

彩色纳米碳酸钙的研制

以纳米碳酸钙中试装置为平台,通过控温碳化、加热湿法染色、加热湿法改性和分散处理,制得了具有良好一次粒子形态的彩色纳米碳酸钙产品。激光粒度仪测试表明,彩色纳米碳酸钙产品的D₅₀约为350 nm,具有粒度分布均匀、分布范围窄等特点。产品在空气中长期放置不氧化、不褪色,说明具有良好的化学稳定性。亲水性实验表明,彩色纳米碳酸钙产品在水中长时间放置、反复搅拌,仍然不沉降、不掉色,说明染色和活化都是牢固的。以酸性媒染蓝黑B染料和硬酯酸为例,分析了纳米碳酸钙的湿法染色和湿法活化机理,并且探讨了硬酯酸分子、染色剂分子和碳酸钙颗粒之间的化学交联作用。     

石墨烯负载纳米二硫化钴的制备及其在锂离子电池方面的应用研究

采用二次水热法将纳米二硫化钴负载于石墨烯上,并通过结构表征和电化学性能测试,探讨了纳米二硫化钴/石墨烯材料作为锂离子电池负极的性能。电容量测试结果表明：在电流密度为100 mA/g条件下,二硫化钴/石墨烯复合材料的首周充放电容量分别为1 610 mA·h/g和774 mA·h/g,测算出的库伦效率为48.1%;循环性能测试结果表明：经过50次循环测算后的复合材料的放电比容量为302 mA·h/g,容量保持率为33.4%;倍率性能测试结果表明：当电流密度回复到100 mA/g时,复合材料的比容量恢复至550 mA·h/g。实验制备的纳米二硫化钴/石墨烯复合材料在锂电池负极的应用上表现出了优异的循环性能和倍率性能。     

纳米SiC颗粒增强NiTi形状记忆复合材料制备及其力学性能和阻尼行为

采用粉末冶金梯级烧结法成功制备出轻质、高强且具有一定孔隙率的纳米SiC颗粒增强NiTi合金基形状记忆复合材料(SiC/NiTi).研究发现,所制备的SiC/NiTi复合材料具有稳定的线性超弹性;SiC颗粒的引入使SiC/NiTi复合材料具有较高的压缩强度和等效压缩强度,且强度随SiC含量的增加而提高.研究还表明,SiC...     

纳米CuCr_2O_4的制备及其对AP热分解性能的影响

采用HLG-5型纳米化粉碎机制备了粒径约为60nm的纳米CuCr2O4,用X射线衍射仪(XRD)、透射电子显微镜(TEM)表征了样品的结构及形貌,分析了纳米CuCr2O4的形成机理,用差示扫描量热仪(DSC)研究了原料CuCr2O4和纳米CuCr2O4对AP热分解性能的影响。结果表明,与原料CuCr2O4相比,质量分数2%的纳米CuCr2O4对AP具有更好的催化性能,可使AP的低温分解峰减弱,高温分解峰温降低67℃,反应速率常数提高数倍,使AP的表观分解热从821J/g提高到1 393J/g,增长率为69.7%。     

Super-hydrophobic property of nano-sized cupric oxide films

Nano-sized cupric oxide (CuO) films with biomimetic super-hydrophobic surfaces were fabricated by isothermally oxidizing nano-sized Cu films prepared by electroless plating on smooth glass substrate following modification with octadecanethiol (CH₃-(CH₂)₁₇-SH). The microstructure characterization showed that CuO films with 54 nm thickness have a dual-scale structure consisting of the 150-200 nm agglomerates composed of the 30-50 nm granules, a similar structure to lotus-leaf. The measurement of wettability showed that CuO films modified with octadecanethiol exhibit a super-hydrophobic property with a water contact angle of ~ 154°. The mechanism leading to the super-hydrophobic property of CuO films was also analyzed based on the results of X-ray photoelectron spectroscopy (XPS).