Oral solid compritol 888 ATO nanosuspension of simvastatin: optimization and biodistribution studies

The purpose of the present investigation was to develop solid lipid nanoparticles (SLNs) of simvastatin in order to enhance its oral bioavailability by minimizing its first-pass metabolism. To achieve our goal, SLNs were prepared by solvent injection technique and optimized by 2³ full factorial experimental design using Design Expert software. The SLN formulations were optimized for amount of compritol, concentration of poloxamer, and volume of acetone in order to achieve desired responses of particle size, entrapment efficiency (EE), and cumulative drug release (CDR). Response surface plots were constructed to study the influence of each variable on each response and the interactions between any two variables were also analyzed. Formulation F₁₀ with particle size of 271.18?nm, % EE of 68.16% and % CDR of 76.23%, and highest desirability value of 0.645 was selected as optimized formulation. The optimized formulation was evaluated for biodistribution and pharmacokinetics by technetium-99m (Tc-99m) radiolabeling technique in mice. The relative bioavailability of simvastatin from optimized SLNs was found to be 220%, substantiating the protective action of SLNs against liver metabolism. However, though the drug initially bypassed the liver metabolism, simvastatin continuously entered in liver to exert its therapeutic action that was evidenced by biodistribution study.     

A Stability-Indicating HPLC Method to Determine Celecoxib in Capsule Formulations

ABSTRACT

A simple and accurate high-performance liquid chromatographic (HPLC) method was developed to determine Celecoxib in capsule formulations. The drug was chromatographed on a reversed-phase C-18 column. Eluents were monitored at a wavelength of 251 nm using a mixture (85:15) of methanol and water. Solution concentrations were measured on a weight basis to avoid the use of an internal standard. The method was statistically validated for linearity, accuracy, precision, and selectivity. Due to its simplicity and accuracy, we believe that the method will be useful for routine quality control analysis.     

ATO透明涂料的隔热性能研究

氧化锡锑（ATO）具有良好的可见光透过性并能有效阻隔红外线,是一种比较理想的透明隔热材料,本文以SnCl4和 SbCl3为原料,氨水为沉淀剂,采用化学共沉淀法制备出纳米ATO粉体,再制成透明隔热涂料,用旋涂法将ATO隔热涂料涂在黑色底漆的薄铁基板上,测试其隔热效果。ATO隔热涂层可使基板的温度下降21.3℃。     

石墨烯/ATO纳米复合材料的制备与表征

以石墨烯、五水四氯化锡、三氯化锑为原料制备了石墨烯/ATO纳米复合材料,并通过XRD,FT-IR,SEM,TEM等分析测试方法对合成的复合材料进行了表征。结果表明:ATO纳米粒子吸附在石墨烯的表面,增加了导电结点、形成了导电网络结构,有效地避免了石墨烯片的堆叠,同时增强了石墨烯的导电性能。     

共沉淀法制备ATO纳米粉末及其光吸收性能

以SnCl4.5H2O和SbCl3为主要原料,采用共沉淀法制备ATO纳米粉末,用DSC-TG、XRD、FESEM、反射率测试等方法对制得的ATO粉末的形貌、微观结构和激光吸收性能等进行表征。研究结果表明:324℃附近有一个结晶放热峰,说明样品开始发生晶化;XRD分析表明ATO为SnO2四方金红石结构,煅烧温度提高到800℃以后,结晶趋于完善;合成的ATO粉末为不规则球形,初始粒径约为30nm;由于锑的掺杂引起的非化学计量缺陷产生了大量载流子,产生等离子激元效应,并且随着纳米尺寸的减小,纳米晶比表面积增大,因此造成红外吸收峰宽化。     

ATO纳米粉体的性能特点与制备研究现状

详细介绍了锑掺杂二氧化锡(ATO)纳米粉体良好的导电抗静电性能、浅色透明性、良好的耐候性和稳定性、纳米粒子特性、多功能性等性能特点,简述了ATO纳米粉体的应用领域;综述了目前制备ATO纳米粉体的固相法、水热法和化学共沉淀法等方法,对几类制备方法优缺点进行分析,进一步确定改进的化学共沉淀法和水热法制备ATO纳米粉体时的最佳实验条件.指出了目前ATO纳米粉体制备存在的几点问题,为进一步研究ATO纳米粉体的制备提供参考依据.     

导电PMMA/ATO纳米复合材料的制备及性能

以掺锑二氧化锡(ATO)粉为导电填料,聚甲基丙烯酸甲酯(PMMA)为基体,采用原位聚合法制备了导电PMMA/ATO纳米复合材料;分析了ATO粉的预处理对复合材料导电性能的影响,并对其热性能和力学性能进行了研究。结果表明,延长球磨时间,可大幅度降低复合材料的体积电阻率;ATO纳米粒子的加入使PMMA主分解温度范围变窄,残余量增大,热稳定性提高;随着纳米粒子含量的增加,复合材料的储能模量提高,玻璃化温度降低。第二分相促使ATO颗粒在基体中形成明显的导电网络结构,使导电性能得到进一步提高。     

4-氨基-1，2，4-三唑-5-酮的制备和快速热分解过程研究

报道了4－氨基－1,2,4－三唑－5－酮（ATO）的制备方法,通过DSC热分析研究了其常规热分解,通过采用T-jump/FT-IR技术对ATO的快速热分解过程进行了研究,提出了其主要气相产物的浓度变化曲线。     

包覆型导电填料的制备及在防静电陶瓷中的应用

以氧化硅粉体为载体,采用非均匀成核法制备了ATO包覆氧化硅导电粉.对比了该导电粉与ATO在防静电陶瓷中的应用效果.结果表明:以包覆型导电粉作为导电填料制备防静电陶瓷能够大大地减少ATO的用量,其中包覆物加入率为12.5%、25%、50%、75%和100%的ATO包覆氧化硅粉体加入陶瓷后分别能节省大约66%、40%、35%、30%和25%的ATO用量.     

Highly transparent low resistance ATO/AgNWs/ATO flexible transparent conductive thin films

Indium-free flexible transparent conductive thin films (TCFs) composed of silver nanowire (AgNW) networks and Sb doped SnO₂ (ATO) layers were prepared on polyethylene terephthalate (PET) substrates. The ATO layers were deposited via radio frequency (RF) magnetron sputtering at room temperature. The AgNWs were achieved via a modified polyol reduction method and embedded between the ATO layers. The effects of AgNW networks and ATO layers on electrical and optical properties of the ATO/AgNWs/ATO flexible tri-layer thin films are investigated. The ATO layers can improve the optical transmittance and reduce the resistivity of tri-layers, and the corresponding mechanisms are proposed. Typically, an ATO/AgNWs/ATO flexible tri-layers show a high figure of merit value (30.06 × 10^-3 Ω^-1) with a low sheet resistance of 7.1 Ω/sq. and a high transmittance of 85.7%. Meanwhile, the tri-layers present excellent mechanical flexibility, and the ATO layers acted as the protecting layers improve the adhesive and environmental stability at high temperature and humidity for the ATO/AgNWs/ATO flexible tri-layers. These results indicate that ATO/AgNWs/ATO flexible tri-layer thin films can be useful for the fabrication of wearable electronic devices.