NH2-MCM-41的改性及其pH响应性释药的研究

采用正硅酸乙酯（TEOS）和3-氨丙基三乙氧基硅烷（APTES）通过共缩聚法合成介孔二氧化硅（MCM-41）。首先对其氨基修饰,再通过有机合成接枝—R基团（—R：—CHO、—OH、—CH₃、—COOH）,制备得到Me-Ph-NH-MCM-41、OHC-Ph-NH-MCM-41、HO-Ph-NH-MCM-41、HOOC-Ph-NH-MCM-41四种不同的药物载体。利用FT-IR、Zeta电位、XRD和SEM对其结构和形貌表征,结果表明NH₂-MCM-41改性成功。以罗丹明B（RhB）为模型进行载药性能测试,并考察了此释药系统在模拟不同pH的体液下的敏感释药行为,同时探究了不同—R基团对释药的影响。结果显示,四种载体在中性条件下几乎不发生药物释放,通过改变环境体系pH可以有效控制药物释放,其释药行为可以用Korsmeyer-Peppas动力学模型来描述。实验表明,释药量：RhB@HOOC-Ph-NH-MCM-41>RhB@OHC-Ph-NH-MCM-41>RhB@HO-Ph-NH-MCM-41>RhB@Me-Ph-NH-MCM-41,不同—R基团的药物载体的pH响应性不同,其中RhB@HOOC-Ph-NH-MCM-41释药量在pH=1.2时可达57.87%,在用于药物智能控释材料方面具有一定的应用潜力。     

Optimizing adsorption of arsenic(III) by NH2-MCM-41 using response surface methodology

Response surface methodology (RSM) was used to optimize process parameters for arsenic (As(III)) removal from aqueous solution using amine-functionalized MCM-41 (NH₂-MCM-41). Four independent variables such as pH, initial metal concentration, temperature and adsorbent dosage were investigated. The optimal conditions to remove As(III) by NH₂-MCM-41 was found to be pH 5.62, initial As(III) concentration 5.00 mg/L, temperature 20 °C and NH₂-MCM-41 dosage 5.00 g/L. XRD, FTIR and SEM analyses testified to the obvious change of the surface morphology and the presence of metal on the sorbent after adsorption.     

pH响应性PAA/毒死蜱/氨基化介孔硅缓释体系的制备与性能

以共缩聚法合成氨基化介孔硅,采用浸渍法制备毒死蜱/氨基化介孔硅,并以带负电荷的聚丙烯酸（PAA）为功能分子,通过静电吸附作用制备了具有pH响应的PAA/毒死蜱/氨基化介孔硅缓释体系。利用XRD、N₂吸附-脱附、TEM、SEM、TG、Zeta电位和FTIR对PAA/毒死蜱/氨基化介孔硅的结构进行了表征,并探究了其在不同pH和温度下的释药行为。结果表明,PAA通过静电作用包覆于毒死蜱/氨基化介孔硅的表面。缓释体系的药物释放主要受到PAA的阻碍作用,PAA修饰载药氨基化介孔硅显示出明显的pH响应性,当pH≤7时,其药物释放速率随pH减小而增大,而在偏碱性条件下的释药速率稍大于中性环境。同时,载药体系的释药速率还受到温度的影响。其释药行为可用Korsmeryer-Pappas动力学模型来描述。     

pH响应改性木质素纳米粒子的制备及释药性能

以酶解木质素（EHL）和N-乙烯基吡咯烷酮（NVP）为主要原料，通过自由基聚合和自组装得到了直径约为50 nm的pH响应性马来酰化木质素-g-聚乙烯吡咯烷酮（MEHL-g-PVP）纳米粒子。考察了化学修饰、聚合物浓度、水滴加速度、搅拌速度、初始水含量和投药量对纳米粒子的形貌、尺寸和载药性能的影响。结果表明，纳米粒子的最大药物负载量可达到35.1%，包封率为64.3%。体外药物释放表明，MEHL-g-PVP具有明显的pH响应能力，在模拟人体内肠道环境和胃液中，布洛芬（IBU）的72h释放量分别为11.1%和63.75%。体外细胞毒性实验结果表明，MEHL-g-PVP载药纳米粒子对正常细胞无细胞毒性，而对结肠癌细胞的具有很好地抑制作用。MEHL-g-PVP纳米粒子有望成为口服药物的理想载体材料。     

超细氧化钛无机改性研究

通过对超细TiO2进行无机包硅改性实验,研究了氧化钛分散性、加酸方式、包覆pH值、改性温度及陈化时间等对包覆效果的影响,分析了致密二氧化硅包覆膜的形成机理,并利用透射电子显微镜TEM和红外分析仪IR对产物进行分析表征,得出无机包硅氧化钛的最佳条件:采用撞击流 旋转填料床反应器(IS RPB),包膜pH=9～10,温度为80～90℃,陈化1h。     

Synthesis of biodegradable thermo- and pH-responsive hydrogels for controlled drug release

Novel intelligent hydrogels composed of biodegradable and pH-sensitive poly(l-glutamic acid) (PGA) and temperature sensitive poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate) (PNH) were synthesized and characterized for controlled release of hydrophilic drug. The influence of pH on the equilibrium swelling ratios of the hydrogels was investigated. A higher PNH content resulted in lower equilibrium swelling ratios. Although temperature had little influence on the swelling behaviors of the hydrogels, the changes of optical transmittance of hydrogels as a function of temperature were marked, which showed that the PNH part of hydrogel exhibited hydrophobic property at temperature above the lower critical solution temperature (LCST). The biodegradation rate of the stimuli-sensitive hydrogels in the presence of enzyme was directly proportional to the PGA content. Lysozyme was chosen as a model drug and loaded into the hydrogels. The in vitro drug release experiment was carried out at different pH values and the release data suggested that both the pH and PNH content played important roles in the drug release behaviors of the hydrogels.     

二步法合成十二烷基多苷机理及动力学探讨

二步法合成十二烷基多苷,生成丁基多苷的催化反应是在固体葡萄糖表面进行的,并且和十二烷基多苷的反应一样都是由亲核反应控制,正丁醇在整个反应过程中起到相当于一种相转移催化剂的作用。在此基础上建立了化学反应控制条件下的动力学模型并给出了相关参数。经验证,实验值与计算值平均误差分别小于4．0％和4．8％。     

Effect of graphene oxide on the pH-responsive drug release from supramolecular hydrogels

Polypseudorotaxane (PPR) hydrogels formed by inclusion complexes between poly(ethylene glycol) (PEG) and α-cyclodextrin (α-CD) are highlighted as promising biomaterial for drug delivery. Here, we report a novel injectable PPR hydrogel containing graphene oxide (GO) for pH-responsive controlled release of doxorubicin hydrochloride (DOX). Our results showed that the gelation rates of the PEG/α-CD supramolecular structures could be tailored depending on the reagent concentrations. The formation of PEG/α-CD inclusion complexes was confirmed by TEM and XRD, the latter further confirming that GO restricts their formation. The supramolecular hydrogels were easily loaded with DOX by simple addition into the PEG solution before the complex formation with the α-CD solution. Noteworthy, disruption of ionic interactions between DOX and GO in the nanocomposite at pH = 5.5 resulted in higher DOX release than under physiological conditions (pH = 7.4). This pH dependence was barely observed in pure PPR hydrogel. These findings introduce DOX-loaded supramolecular hydrogels nanocomposites as promising carriers for pH-responsive and therefore localized, drug delivery systems.     

Preparation,modification and characterisation of polymer-supported species

Techniques for the preparation of polymer supports are described. Details of suspension polymerisation reactions are given using novel resins based on poly(methacrylonitrile) as an example. The structure of supports is discussed, including both macroporous vinyl polymer based systems, and macroporous polysaccharide based species. Methods of derivatising supports are summarised with recent examples illustrating the ‘chemical modification’ approach, and the ‘functional monomer’ approach. Newer inert supports are introduced and the technique of γ-ray irradiation grafting described as one method of achieving derivatisation of these potentially very useful materials.     

纳米二氧化硅在外墙涂料中的改性研究

在传统的建筑用外墙涂料中加入纳米SiO2得到纳米涂料,比较了加入纳米SiO2前、后涂料涂膜的性能.结果表明,涂料中纳米SiO2的最佳用量为0.3～1.0 g,在此用量内,所得纳米涂料的稳定性,流平性均有所提高;涂膜的耐洗刷性为原来的2倍,耐碱性从原来的48 h无异常增强为7 d无异常,耐老化时间从之前的500 h延长至1 000 h.     

One-pot synthesis and modification of silica nanoparticles with 3-chloropropyl-trimethoxysilane assisted by microwave irradiation

Industry and academia have shown great interest in the synthesis of organic–inorganic hybrid material because the modification of inorganic supports with organic groups increases the options for using these materials. Microwave irradiation as a heat source is an alternative tool compared with conventional heating (oil bath or furnace) to reduce the reaction times during the synthesis of these materials. Thus, the purpose of this work was to synthesize an organic–inorganic hybrid material, more specifically silica nanoparticles modified with 3-chloropropyl-trimethoxysilane, using microwave irradiation as the heat source. The hybrid materials were synthesized using the sol–gel method, with microwave irradiation for 10, 25, and 40?min, at 300?W of power and temperature of 40, 60, and 80°C. Elemental analyses, FTIR, and N₂ adsorption–desorption isotherms were developed to characterize the materials. It can be concluded that when microwave irradiation is used as a heat source, the reaction rate is accelerated and the surface area of hybrid materials increases considerably.     

FeCl3-HCl-C2Cl4体系浸出硫化锌矿的动力学研究

针对FeCl3-HCl-C2Cl4体系浸出硫化锌精矿过程，建立了以固体产物层扩散控制和混合扩散控制浸出的核收缩动力学模型。动力学研究和浸出过程矿粒表面的SEM分析结果表明，在相同的搅拌强度下，FeCl3-HCl体系符合固体产物层扩散控制的核收缩过程，四氯乙烯能有效地溶解矿粒表面形成的固体硫层，提高固体产物层扩散控制的速度，并且随四氯乙烯加入量的增大；对于FeCl3-HCl-C2Cl4体系则由固体产物层扩散控制变为混合扩散控制的的核收缩过程，显著地提高了浸出速率。     

月桂酸二乙醇酰胺缩合反应动力学研究(一)

在实验室条件下,通过选择优化的工艺条件,从理论上对月桂酸二乙醇酰胺缩合反应进行了研究。并通过对实验数据分析,提出了月桂酸二乙醇酰胺缩合反应的二级不可逆动力学模型。     

聚酰亚胺的合成与改性研究

聚酰亚胺树脂是一种耐热性好、机械强度高且介电性能优异的高分子材料。该文综述了聚酰亚胺的合成与改性方面的研究,并对聚酰亚胺的发展进行了展望。     

Synthesis and characterization of a novel pH-responsive nanocomposite hydrogel based on chitosan for targeted drug release

Over the last decade, nanocomposite hydrogels have been provided a new approach for the biomedical field. In this work, a novel pH-responsive nanocomposite hydrogel was fabricated using simultaneous in situ formation of magnetite iron oxide nanoparticles and hydrogel networks of poly(acrylic acid) grafted onto chitosan. The effects of various types of precursor molecules, pH, salt, and loading pressure were examined on the swelling properties of resulting nanocomposite hydrogels. The synthesized nanocomposite hydrogel was well characterized using different instruments. In vitro drug releasing behavior of doxorubicin was studied at pH 5.4 and 7.4. The drug release mechanism was investigated through different kinetic models. These experimental results open a new opportunity to make pH-responsive nanocomposite hydrogel devices for controlled delivery of drug.     

Dual thermo- and pH-responsive poly(N-isopropylacrylamide-co-(2-dimethylamino) ethyl methacrylate)-g-PEG nanoparticle system and its potential in controlled drug release

Polymer Bulletin - Stimulus-responsive nanoparticles have been widely used for many applications in biotechnology and medicine. In this study, dual thermo- and pH-responsive...     

Ibuprofen grafted on poly(2-hydroxyethylmethacrylate): Synthesis,mass transfer,and in vitro drug release investigations

Poly(2-hydroxyethylmethacrylate-graft-ibuprofen) (IpGH) of different ibuprofen (Ibu) contents was prepared by grafting of Ibu groups on poly(2-hydroxyethyl methacrylate) (PHEMA) in an esterification reaction route. The resulted copolymers were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, differential scanning calorimetry, thermal gravimetric analysis, X-ray diffraction, and scanning electron microscope analysis. The cytotoxicity test and the free radical scavenging ability of this material were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium (MTT) and 1,1-diphenyl-2-picryl-hydrazyl assay methods, respectively. The in vitro release study of Ibu through a retro-esterification reaction of IpHG material during 3 days reveals that the release dynamic depends on the initial Ibu grafted, pH media, and the swelling degree of PHEMA. It was also revealed that the water solubility of Ibu easily reached a maximum of 0.216?mg?mL^?1. The diffusion of Ibu through the polymer matrix obeys the Fickian model. The estimated distribution of the cumulative drug released in different simulated digestive organs reveals that the IpHG7 containing 6.69?mol% of Ibu content showed the best performance.     

Preparation and characterization of Co/SiO2, Co-Mg/SiO2 and Mg-Co/SiO2 catalysts and their activity in CO hydrogenation

Co/SiO₂, Mg-Co/SiO₂ and Co-Mg/SiO2 catalysts were prepared from acetate, nitrate or carbonyl precursors. The catalysts were characterized by XRD, XPS, SIMS and TGA. The steady-state activity and product distribution of the catalysts were evaluated in synthesis gas reactions at 0.5 MPa and 235-290°C using 3 : 1 : 3 molar ratio of Ar : CO : H₂. The activity in CO hydrogenation decreased in the precursor order Co₂(CO)₈>Co(NO₃)₂> Co(CH₃COO)₂, and the probability of chain growth decreased in the precursor order Co(NO₃)₂>Co₂(CO)₈>Co(CH₃COO)₂. Alcohol yields were highest with Co₂(CO)₈, and lowest with Co(NO₃)₂, Magnesium promotion influenced the catalyst activity and decreased the CO₂ formation, but the promotion effects were less profound than those of the precursor. Surface studies on partially magnesium covered cobalt foil model catalysts suggested that magnesium promotes CO dissociation and chain growth, neither of which were, however, observed in the supported catalysts.     

MCM-41介孔分子筛的合成、改性及应用研究进展

介绍了MCM-41介孔分子筛的优点,主要表现在具有较大的比表面积,孔体积与孔径和可调变等。综述了MCM-41介孔分子筛的合成方法与改性研究现状,阐述了MCM-41介孔分子筛的应用研究进展。     

A novel polymeric biomaterial based on carboxymethylstarch and its application in controlled drug release

This study reports investigation of the sustained release behavior of a model drug (acetylsalicylic acid) from carboxymethylstarch (CMS) based matrix. CMS was prepared by incorporation of carboxymethyl groups in the starch moiety; by reacting starch with sodium salt of monochloro acetic acid in presence of sodium hydroxide. The in vitro drug release study was performed by United States Pharmacopeia rotating paddle method, at various pH. The rate of drug release from the above matrix was found to increase with increase in pH. Further, the release behavior of the drug from the CMS based matrix was found to be non‐Fickian, n value being between 0.80 and 0.85, suggesting that the release was controlled by a combination of tablet erosion and diffusion of the drug from the swollen matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009