侧链含5-氟尿嘧啶甲壳胺的合成及其抗肿瘤活性的研究

本文报道了以不同分子量的甲壳胺为载体,制备了侧链含5-氟尿嘧啶的一系列高分子载体药物;通过定氮分析测定了H_2N-基的反应率;由IR、UV和~(13)C-NMR确定了载体药物的结构;模拟生理条件考查了在不同pH的缓冲溶液中5-氟脲嘧啶或其衍生物的水解释放率。体外初步实验结果表明,具有Ⅰ和Ⅱ结构的载体药物对艾氏腹水癌细胞有较强的杀伤作用。     

乳酸-磷酸酯共聚物为载体的高分子药物的合成及其控释研究

以5-氟尿嘧啶(5-FU)为药物模型,以乳酸-磷酸酯共聚物为高分子药物载体,合成了侧链带药的乳酸-磷酸酯共聚物药物。用¹HNMR、IR、UV谱对其结构进行了表征。测定高分子药物中5-FU的含量,研究了高分子药物的体外释药性能及共聚物组成对释药性能的影响。     

5-氟脲嘧啶的D-氨基葡萄糖衍生物的合成及其抗肿瘤活性的研究

以α-氨基酸为连接基,将5-氟脲嘧啶同D-氨基葡萄糖键连合成了4种新的5-氟脲嘧啶的衍生物,并确认了它们的结构。体外抗肿瘤活性实验结果表明:链连的D-氨基葡萄糖使5-氟脲嘧啶的抗肿瘤活性有明显的提高,表明它们之间可能存在着某种抗肿瘤的协同作用。     

8-羟基喹啉化学修饰壳聚糖亚铁配合物的合成及结构表征

为了利用高分子壳聚糖的生物特性降低药物的毒副作用,寻找理想的高分子药物载体,增加药物的生物特性,本文以高分子壳聚糖为载体,以8-羟基喹啉对其进行共价修饰,合成了喹啉类抗疟杀菌药的高分子药物前体,为增加其活性,与亚铁配位,合成了壳聚糖-8-羟基喹啉-亚铁配合物,用元素分析、TG-DTA分析、IR光谱、UV光谱和荧光光谱等研究了配合物的性质,并优化了配合物合成条件.结果表明,CTS-HQ对Fe²⁺离子的吸附等温线符合Langmuir吸附等温线方程,在室温下,pH=4时吸附8h的饱和吸附量Q_max=86.96mg/g,K=1.474J/mg.     

新型N1-(2-呋喃烷基)-5-氟脲嘧啶的α-羟基(硫代)膦酸酯衍生物的合成

通过对N^1-(2－呋喃烷基）－5－氟脲嘧啶的氧化以及与O,O－二乙基硫代亚磷酸酯的加成反应合成了新型N^1-(2－呋喃烷基）－5－氟脲嘧啶的α-羟基（硫代）膦酸酯衍生物,进一步以间氯过氧苯甲酸氧化得到相应的α-羟基膦酸酯衍生物 。     

含嘧啶碱基和膦甲酸乙酯的聚磷酸酯的合成及其抗肿瘤活性

本文通过十一种二羟基嘧啶衍生物单体与P,P-二氯膦甲酸乙酯进行缩聚反应,合成了十一种新的含5-氟脲嘧啶、尿嘧啶、胸腺嘧啶和膦甲酸乙酯的聚磷酸酯。用核磁、红外光谱及元素分析确定了聚合物的结构。进行了部分聚合物抗动物肿瘤活性试验,含5-氟脲嘧啶和膦甲酸乙酯的聚磷酯对小鼠艾氏腹水癌的抑制率可达56％。     

聚天冬酰胺衍生物药物/基因载体的合成和应用

与碳链聚合物相比,聚氨基酸类高分子由于其生物相容性好、可降解代谢、毒副作用低等优点而被广泛应用于生物医药领域。基于天冬氨酸的聚天冬酰胺衍生物,其合成方法简单多样,通过对其修饰改性可制备出具有各种环境响应性（温度、pH和还原敏感）的智能高分子,得到高效、低毒的药物/基因载体,实现可控释放、增强疗效、降低药物副作用的目的。本文重点介绍了聚天冬酰胺衍生物（特别是刺激响应性聚天冬酰胺衍生物）的合成改性方法、及其在药物和基因载体领域最新的研究进展,并对其发展前景进行了展望。     

高分子药物研究Ⅸ.1,3-二羟烷基-5-氟尿嘧啶与二氯磷酸酯缩聚物的合成

<正> 核酸的抗代谢物是研究正常细胞和肿瘤细胞代谢、发展新的抗肿瘤药物的极好来源。近年来合成含核酸碱基、核酸碱基衍生物的聚合物引起了人们的极大兴趣。在这些聚合物中,核酸碱基及其衍生物均以侧基支载在聚合物上。我们将5-氟尿嘧啶引入不同化学结构的高分子主链上,合成了一系列高分子抗癌药物,经动物试验和一期临床观察     

温度及pH敏感的树枝状高分子衍生物合成及药物控制释放研究

对合成的系列聚酰胺-胺型(PAMAM)树枝状高分子进行端基的羟基化和氯乙酰化两步修饰,使PAMAM最外层接上烷基氯.以修饰产物为引发剂,通过原子转移自由基引发甲基丙烯酸N,N-二甲氨基乙酯(DMAEMA)聚合得到树枝状PAMAM高分子衍生物,并对其结构用FTIR、1H-NMR和粒径分析进行了表征.紫外可见分光光度仪测定证实此高分子具有温度及pH敏感性.通过对小分子药物控制释放研究表明,此树枝状高分子衍生物通过环境pH值可有效地控制小分子药物的释放.     

几种常见药物的高分子衍生物的合成

小分子药物高分子化能延长药效,减小副作用,是改进现有药物的重要方法之一。目前研究的高分子药物大致有两类:(1)高分子本身有药效;(2)高分子本身无药效,但可释放出小分子药物。例如,Vogl等合成的5-乙烯基水杨酸甲酯聚合物本身有抗紫外辐射功能,李福绵等合成的聚甲基丙烯酸-β-(乙酰水杨酰氧)乙酯等本身虽不是药,但可释放出阿斯匹林。我们希望合成出兼有以上两类特点的高分子药物,为此合成了几种常见药物的高分子衍生物:聚甲基丙烯酸水杨酸酯(PSAMA),聚甲基丙烯酸对乙酰胺基苯酯(PAPMA),聚甲基丙烯酸磺胺嘧啶酰胺(PSDMA)和聚甲基丙烯酸乳酸酯(PLAMA)。     

Synthesis Structure and Behavbr of Polymeric Drugs Covalently Linked 5-Fluorouracil

Four series of polymeric drugs with 5-Fluorouracil(5-FU) cova-lently linked in side chain were synthesized by the use of starch and carboxylmethylcellulose and two new 5-FU derivatives were also synthesized by using molecular sieve as a catalyst.Their structures were determined by IR,1H NMR and mass spectra.The changes in the Nitrogen content of polymeric drugs with reaction conditions and the influences of the N content on their limiting viscosity were studied.The hydrolysis of 5-FU from starch and carboxylmethylcellulose derivatives in various of buffer were researched by simulating physiologically acid-alkali enviroment.In addition,anticancer activity(in vivo and in vitro) of some starch derivative has been preliminaryly observed.     

Polysaccharide functionality through extrusion processing

Extrusion processing is a technology applied in the food and pharmaceutical industry for affecting product microstructure, product chemistry or the macroscopic shape of products. Starch based products are often extruded to break down the starch granule to render it digestible and to produce a shaped product. Encapsulation of flavors, nutrients and drugs is another frequent application of extrusion processing. This short review article is concerned with the use of extrusion processes to modify polysaccharide functionality. Extrusion processes are applied to polysaccharides for specific purposes such as physical modification or chemical modification (reactive extrusion), manufacture of confectionary gels and encapsulation of flavors or drugs. Non-starch polysaccharides and confectionary gels have also been extruded. Another application area is in the field of dietary fibers, obtained through extrusion processing of by- or waste-products of the food industry. The focus of this article is on extruding starch and other polysaccharides as an ingredient rather than as part of a final food product obtained by extrusion processing. It concludes with a discussion on extrusion as microstructure generating process and the relevance of this application to taste perception in semi-liquid foods.     

Pore-Forming Agents for the Supporting Ni-Based SOFC Anode

The effect of the type (semolina, starch, and ashless filter paper) and amount (5 and 10 wt %) of pore-forming agents on the structure of supporting Ni-cermet anodes and characteristics of solid-oxide fuel cells on their basis has been studied. It has been found that the use of paper fibers as the pore-forming agent doubles the open porosity of the anode as compared with equal amounts of semolina or starch. It has been shown that the long cylindrical pores formed by fibers allow fast transport of gases through the anode bulk, which has a positive effect on the fuel cell characteristics.     

Synthesis and characterization of a starch‐modified hydrogel as potential carrier for drug delivery system

Synthesis and characterization of a new hydrogel were carried out using a chemically modified starch (starch‐M) consisting of coupling C?C bounds coming from glycidil methacrylate (GMA) onto the polysaccharide structure. ¹³C NMR, ¹H NMR, and FT‐IR spectroscopies were used to confirm the incorporation of such groups onto the starch‐M. The hydrogel was prepared by a crosslinking polymerization of starch‐M using sodium persulfate as an initiating agent. The starch‐M hydrogel shows morphology clearly different from that of the raw starch film due to the presence of voids on its surface. The swelling process of the starch‐M hydrogel was not significantly affected by changes on the temperature or on pH of the surrounding liquid, indicating the such behavior can be then understood by a diffusional process, resulting from its physical–chemical interactions with the solvent. The values of the diffusional exponent n were on the order of 0.45–0.49 for the range of pHs investigated, demonstrating that the water transport mechanism of starch‐M hydrogel is more dependent on Fickian diffusion, that is, controlled by water diffusion. Such starch‐M hydrogel is a promising candidate to be used in transporting and in preserving acid‐responsive drugs, such as corticoids, for the treatment of colon‐specific diseases, for example, Crohn's disease. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2567–2574, 2008     

Preparation and Characterization of Electroactive Biopolymers

Biopolymers have the potential for use as a matrix for applications such as controlled release devices, environmentally sensitive membranes, mimic materials and energetic applications. Renewable resources (such as starch) can be utilized as polymer matrices for electroactive materials that are sensitive to their environment. Natural polymers are generally more environmentally-friendly and biocompatible than existing synthetic products. Thermoplastic starch is naturally insulative; however, the chemical, electrical, and mechanical properties of the biopolymer matrix can be tailored for specific functionality in a continuous process utilizing reactive extrusion. Conductance can be measured in the solid state by a direct-current resistance method. Ion-conducting materials, produced by doping thermoplastic starch and biopolymers with metal halides, have 5 orders of magnitude greater conductance than native materials. There is a correlation between polymer mobility and conductance. Plant or microbial biopolymers with ionic functional groups have shown promise for higher levels of conductance. The conductance approaches the level of synthetic polymer electrolytes.     

Iodine-starch clathrate complexes in low-field acoustic fields

Experimental data on the kinetics of formation and decomposition of iodine-starch clathrate complexes (amyloiodine and amylopectoiodine) in low-frequency (5–45 Hz) acoustic fields are reported. The biological activity of these compounds suggests their use as a model of biocatalysts, in which iodine represents the coenzyme active group and starch homopolysaccharides (amylopectin and amylose) represents the apoenzyme.     

Genetically Modified Starch as an Industrial Raw Material

Abstract

Starch is an important raw material for industrial applications, both for food and nonfood purposes. Of particular interest is the use of starch as a nonpetroleum chemical stock for the manufacture of biodegradable polymers. Annual EC starch production is nearing 10 million tons, with 80% from cereals and 20% from potatoes, and grows at 4?5% annually. The potential for genetically modified starch is considered very high. Such starch offers significant advantages: 1) chemical modifications, which are expensive and environmentally hazardous, are replaced; 2) novel carbohydrates can be produced.     

Short-term changes in carbon isotope composition of soluble carbohydrates and starch: from canopy leaves to the root system

Changes in the 13C discrimination of current leaf photosynthesis might have profound impacts on root respiratory substrates. Therefore, the aim of this study was (1) to refine a method for the isolation of root and leaf starch and soluble sugars (neutral fraction) for stable carbon isotope analysis and (2) to assess the short-term temporal variability of the C isotope composition (delta13C) of starch and of the neutral fraction of beech roots and leaves at different canopy heights. An existing method for isolating starch for stable C isotope analysis based on enzymatic hydrolysis was modified to account for the low starch content of the samples. This was achieved by removing the enzyme (alpha-amylase) by ultrafiltration after the hydrolysis, resulting in very low carbon blanks. The neutral fraction was separated from organic acids and cations by ion-exchange chromatography. An anion-exchange resin in the [HCO3]--form was chosen that ensured high precision of C blanks. Beech leaves at 5, 10 and 20 m above the forest floor as well as roots were sampled six times during a day/night cycle in July 2003. Delta13C values of bulk material, starch and the neutral fraction increased from the lower to the higher canopy with mean differences between 5 and 20 m of 3.8, 3.4 and 2.7 per thousand for the delta13C values of starch, neutral fraction and bulk foliage, respectively. The delta13C value of foliar starch increased from the morning to the afternoon and decreased during the night, but diurnal differences (up to 3.1 per thousand) were only statistically significant for leaves sampled at 5 and 10 m height. In roots, no diurnal variation in the delta13C of starch was observed during the short time frame of one day and the delta13C of the neutral fraction did not differ between samples taken at 16:30 and 22:00. Calculated delta13C values of starch, which was mobilised during the night, were more positive than the total starch (all sampling times pooled) in leaves. Furthermore, the delta13C values of mobilised starch were approximately 5 per thousand more positive than that of the mobilised neutral fraction. Hence, the delta13C of potential sources for export from canopy leaves to roots varied considerably in their C isotope composition.     

Synthesis of CMS under ultrasonic irradiation

Starch is a granular mixture of nomopolymers of α-D-glucopyranosyl units. These polymer molecules are hydrogen bonded and aligned radially in the granule. Starch is an important ingredient in manufacturing a wide range of industrial products such as food, paper, textiles, and building materials. Today, starch is chemically modified for speciality use. Modification of starch properties by derivatization is an important factor in the continued and increased use of starch to provide thickening, gelling, binding, adhesive, and film forming functionality. Carboxymethylstarch (CMS) is one of important starch derivatives. The study in exploitation and use of CMS has been acitvated since 1980s. At present, it is widely used in medicine, functional food, commodity, dope and so on.     

Spectrochemical determination of impurities in telluric acid

An emission spectrographic method is described for determination of 20 elements present as impurities in telluric acid. Samples are excited in a 12-A. d.c. arc with the use of NaCl-KCl as a spectrographic buffer and germanium as internal standard. The limit of determination lies between 10(-5) and 10(-2)%. The precision of the method calculated as relative standard deviation is 10-25%.