Cosolvency of Dimethyl Isosorbide for Steroid Solubility

Dimethyl isosorbide (DMI), which is currently under investigation for its potential use as a pharmaceutical vehicle and drug permeation enhancer, is a water-miscible liquid with relatively low viscosity. The solubilization behavior of DMI as a cosolvent for nonpolar drugs was characterized via dielectric constant measurements of binary solvent systems containing DMI and either water, propylene glycol (PG), or polyethylene glycol (PEG). Evidence from the dielectric constant profiles and NMR studies suggest that DMI undergoes complexation with water and PG, but not with PEG, through hydrogen bonding interactions. The solvent complexation exhibited a major effect on the solubilities of prednisone, dexamethasone, and prednisolone in the mixed solvent systems. Maximum solubility of each drug was found to occur near a DMI/water or DMI/PG concentration ratio of 1:2. In the DMI–PEG mixed system, while there is no apparent interaction between DMI and PEG molecules, the solubility of prednisone was found to increase with decreasing dielectric constant.     

多官能度活性橡胶增韧环氧树脂的研究：Ⅲ.三元共混增韧环氧树脂

本文研究了双酚A对多官能度环氧基和羧基聚丙烯酸正丁酯橡胶增韧环氧树脂的影响。结果表明,加入双酚A,拉伸断裂能有大幅度提高,同时不降低弹性模量。这可能是由椽胶提高断裂伸长与双酚A提高屈服应力产生协同效应的结果。对羧基橡胶增韧的三元共混体系,拉伸断裂能随羧基官能度上升而增加。断裂面的形态研究表明,由于羧基橡胶与双酚A的酯化反应,大大减少了羧基橡胶聚集对增韧的不利影响。     

橡胶活性官能团对增韧环氧树脂动态力学性能的影响

用动态扭摆法测试聚丙烯酸丁酯橡胶增韧环氧树脂的动态力学行为,研究在环氧树脂低固化度和高固化度时,橡胶活性官能团种类(环氧基官能团与羧基官能团)和数量(官能度)对其影响。研究体系中橡胶玻璃化转变温度(Tg)的移动大小,与橡胶和基体树脂健合程度之间的关系。     

Ethylene vinylacetate copolymer particles dissolved in polyvinyl alcohol (2,000-mer) solution as an embolic material for vascular anomalies

We have prepared a new material for embolisation: ethylene vinylacetate copolymer dissolved in polyvinyl alcohol. When in contact with blood, polyvinyl alcohol rapidly becomes a soft gel, which is accompanied by wedging of the ethylene vinylacetate copolymer. We analysed the histopathology of intra-arterial microemboli in rats, after intracarotid injection of this material. We confirmed that it was applicable to embolisation for neurosurgical treatment.     

Aspects of silicone rubber as an encapsulant for neurological prostheses

Silicone rubber is not, at first sight, a promising material with which to encapsulate a piece of implantable microelectronics expected to last ten or twenty years. It is well known to be very permeable to water. In fact, if correctly applied, it performs very well for ten years, possibly longer. The paper considers the part player by osmosis in achieving satisfactory performance combined with simple technology.     

ZMW型环氧乙烷灭菌箱对骨移植材料灭菌效果的初步观察

目的 :观察ZMW型环氧乙烷灭菌箱对异体骨材料灭菌效果 ,旨在寻找一种安全、经济的灭菌方法。方法 :清洁条件下取骨 ,制成 0 .5cm× 0 .5cm× 2cm湿润骨材料和干燥骨材料 ,抽取样本 ,用ZMW型环氧乙烷灭菌箱 (15 0L)在不同温度及时间下消毒 ,以环氧乙烷指示胶带是否变色作为灭菌指标 ,样本在消毒前后分别作细菌培养。结果 :不同消毒条件下 ,每批样本均有细菌生长 ,干燥骨材料有菌率高于湿润的骨材料。结论 :ZMW型环氧乙烷灭菌箱不能使异体骨移植材料完全达到灭菌的要求 ,环氧乙烷指示胶带不能作为骨移植材料的灭菌指标 ,干燥可能使细菌的抗环氧乙烷能力增加 ,从而间接的影响了环氧乙烷的消毒效果。     

橡胶木粉填充LLDPE复合材料的结构和力学性能

用橡胶木粉填充线性低密度聚乙烯(LLDPE)，研究了酸、碱溶液预处理木粉的效果和硅烷偶联荆(KH-570)、MMA接枝的天然橡胶胶乳(MGL-30)两种改性剂对橡胶木粉表面改性的效果，以及未粉粒径和填充量等对木粉／LLDPE复合材料力学性能的影响，并用SEM对复合材料拉伸断面的形态结构进行了分析。结果表明：木粉的拉径、木粉填充量和改性荆用量对复合材料的力学性能有较大的影响，经碱溶液预处理再用改性荆改性后的木粉能有效地改善木粉与LLDPE的界面粘结强度，提高橡胶木粉／LLDPE复合材料的力学性能。     

A method for reducing background tracks in plastic detectors

The purpose of the present study was to reduce background tracks by removing a given surface layer of the 250 μm thick lexan polycarbonate foils before exposure to alpha particles. Ethylenediamine solution was used for taking layers from the surface of the foils.     

Use of an in Vitro Model for the Assessment of Muscle Damage from Intramuscular Injections: in Vitro-in Vivo Correlation and Predictability with Mixed Solvent Systems

The potential of binary mixtures of propylene glycol–water, ethanol–water, and polyethylene glycol 400–water to cause skeletal muscle damage (myotoxicity) following intramuscular injection was examined with an in vitro model using the isolated rat muscle. At moderate concentrations (20–40%, v/v) of the organic cosolvent, the order of myotoxicity was propylene glycol > ethanol polyethylene glycol 400. The in vitro results were then compared with in vivo toxicity in rabbits after injection of normal saline, 40% (v/v) polyethylene glycol 400, 40% (v/v) propylene glycol, indocyanine green in normal saline, and indocyanine green in 40% (v/v) propylene glycol. Employing the area under the creatine kinase activity curve from 0 to 72 hr as the index of skeletal muscle damage, an excellent in vitro–in vivo correlation was observed. The basic myotoxicity relationships obtained from the binary cosolvent systems were then used to examine the myotoxicity of ternary organic cosolvent mixtures. Several mixed solvent systems with the same theoretical molar solubilization power for a model compound, diazepam, were selected to determine (1) if myotoxicity can be reduced by changing the composition of the ternary mixtures and (2) if myotoxicity of the individual components is additive. For the solvent systems containing propylene glycol, ethanol, and water, the total myotoxicity equaled the sum of the individual myotoxicity of each component. In contrast, for the solvent systems containing polyethylene glycol 400, the total myotoxicity was only half of the sum of individual toxicities. These results suggest that polyethylene glycol 400 in mixed cosolvent systems might have a protective effect on the myotoxicity generated by intramuscular injections.