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.     

Poly(2-hydroxyethylmethacrylate-graft-folic acid), synthesis,solubility enhancement,and release dynamic of folic acid

A series of poly (2-hydroxyethylmethacrylate-graft-folic acid) (FAHEMA) systems are synthesized by grafting of folic acid (FA) into poly (2–hydroxyethylmethacrylate) via an esterification reaction. The structure of these copolymers is confirmed by NMR and CHN analyses. The thermal behavior of these materials is characterized by DSC and TGA analyses. The surface morphology of FAHEMA films before and after the release process is examined by the SEM method. The cumulative FA released in different pH media from FAHEMA materials occurred via a retro-esterification reaction at body temperature during 72 h in which the influence of the swelling degree of PHEMA, the FA content and pH media on the dynamic release is widely investigated. The results obtained revealed that the solubility of FA in water deduced from the release process is widely improved compared with literature reports. It is also revealed that the diffusion of water in different pH media through the PHEMA matrix and that of FA through FAHEMA materials perfectly obeyed the Fickian models. It was deduced from the kinetic study that the release performance is obtained with the copolymers containing initially 10 and 20 wt% of FA contents.     

Controlled drug release of 5-amino salicylic acid by poly(2-hydroxyethylmethacrylate) grafted agar

The utilization of poly (2-hydroxyethylmethacrylate) grafted agar (Ag-g-P(HEMA)) as a matrix for the controlled release of 5-aminosalicylic acid was investigated. Grafted copolymers of 2-hydroxyethylmethacrylate (HEMA) monomers on agar were synthesized by microwave assisted method. In vitro drug release studies were performed at pH values of 2 and 7 in order to investigate the possibility of pH triggered release for colon targeted drug delivery. Further, the percent grafting vs. t₅₀ (the time taken for release of 50% of the enclosed drug) value was studied and the results indicate that it may be possible to develop a programmable drug release matrix based on grafted polysaccharide. Ag-g-P(HEMA) appears to be a useful matrix for controlled release.     

负载药物替莫唑胺的纳米羟基磷灰石/聚乳酸-羟基乙酸共聚物微球的缓释行为

以聚乳酸-基乙酸共聚物(PLGA)和纳米羟基磷灰石(nHA)作为生物降解材料制备了药物替莫唑胺(Temozolomide,TMZ)的缓释系统.采用湿法化学工艺制备了球状和棒状的nHA粉末.将TMZ药物分子负载在nHA表面(nHA-TMZ),再通过乳化溶剂挥发法将nHA-TMZ包裹在PLGA微球中,同时研究了微球中nHA的形貌和含量对缓释微球物化性能的影响.用扫描电镜、紫外分光光度计分别测定了微球的结构、形貌、药物包封率和缓释行为.相比于不含有nHA的TMZ/PLGA缓释微球,nHA的介入能够显著提高药物的包封率,并且包封率与nHA的加入量有关.此外,药物释放实验表明包裹在微球中的nHA的形貌和溶解速率能够影响微球的缓释行为.     

Preparation and Controlled Drug Release Characteristics of Thermoresponsive PEG/Poly (NIPAM-co-AMPS) Hydrogels

Thermosensitive hydrogels were prepared by free radical polymerization of N-isopropylacrylamide (NIPAM) and 2-acrylamido-2-methylpropanesulphonic acid (AMPS) in presence of polyethylene glycol (PEG) as macroinitiator. The incorporation of functional monomer in the hydrogel was confirmed by infrared spectroscopy. The equilibrium swelling ratio (ESR), deswelling rate, volume transition temperature, and surface morphology of synthesized hydrogels are found to be dependent on concentration of AMPS monomer in the feed composition. The equilibrium swelling ratio (ESR) and water retention properties increase with increasing AMPS concentration in hydrogels and decrease with increasing salt concentration in external medium. The hydrogel with high dose of AMPS has high loading efficiency of theophylline drug, whereas the in-vitro release of the drug is delayed for a prolonged period in swollen gels above LCST of PNIPAM.     

纤维素/聚乙二醇/维生素共混膜的制备与缓释性能研究

介绍了在纤维素/聚乙二醇体系中加入维生素C制备成药物缓释膜的过程,并研究了其在水中的药物缓释性能。结果表明,固液比、pH和温度这三个条件都对药物缓释有非常明显的影响。例如,药物在中性条件下的缓释一般是随着固液比的增大和温度的升高而加快的,但在高分子材料的结晶温度区域进行时也受到抑制。此外,在酸性环境中药物缓释在初始时是受到抑制而后逐渐以脉冲式进行。值得指出的是,药物缓释在碱性条件下完全不发生,并出现与缓释相反的吸附现象。     

聚过氧马来酸消毒剂的制备及性能

用过氧化氢对聚马来酸酐进行氧化,制备出了一种聚过氧马来酸消毒剂。研究了氧化反应的条件、产物的稳定性和杀菌效果。结果表明,在n(酸酐基)∶n(H2O2)=1∶1.25,温度5℃的条件下反应6 h,可得到过氧羧基浓度为2.95 mol/L的消毒剂溶液。向此溶液中加入稳定剂乙二胺四甲叉膦酸(EDTMP)后,在20℃保存,60 d内过氧羧基的浓度基本不变,100 d后浓度只降低10%。过氧羧基浓度为0.012 5 mol/L和0.025 mol/L的聚过氧马来酸稀释液,可分别在10 m in和5 m in内完全杀灭金黄色葡萄球菌和大肠杆菌,并且对金属基本无腐蚀或只有轻度腐蚀。该消毒剂已经过扩大实验,杀菌性能良好。     

改性聚天冬氨酸/聚丙烯酸/羧甲基纤维素复合高吸水性树脂的制备和性能研究

以改性聚天冬氨酸（KPAsp）、丙烯酸(AA)和羧甲基纤维素(CMC)为原料,采用水溶液聚合法合成改性聚天冬氨酸/聚丙烯酸/羧甲基纤维素(KPAsp/PAA/CMC)复合高吸水性树脂。通过红外光谱（FTIR）、热重分析(TGA)和扫描电镜（SEM）对产物组成结构、热稳定性和表面形态进行表征。探讨了CMC和AA用量对复合高吸水性树脂吸液性能的影响,结果表明当m(CMC)/m(AA)/m(KPSI)=0.15:3:1时,树脂的吸液性能最佳,在去离子水和0.9% NaCl溶液中的吸水倍率分别达到830 g/g和130 g/g。研究了不同组成KPAsp/PAA/CMC吸水性树脂的盐敏感性、温度敏感性和pH敏感性,以及树脂在人工血、人工尿和不同浓度乙醇水溶液的吸液性能,结果表明复合树脂盐敏感性提高,在盐溶液中的吸液倍率为NaCl>FeCl3>CaCl2;低临界溶解温度(LCST)比KPAsp提高了15℃;在溶液pH=5和pH=9出现了两吸液高峰;在人工血和人工尿中的吸液倍率最大为211 g/g和142 g/g,在50%的乙醇水溶液中吸液倍率最大为295 g/g。     

壳聚糖/聚丙烯酸共聚物微球的制备及性能

以环己烷为油相,壳聚糖溶液为水相,运用反相乳液聚合法制得了具有pH敏感性的壳聚糖/聚丙烯酸共聚物微球。讨论了微球在pH=1～10缓冲溶液中的溶胀率变化,研究表明,微球在强酸性(pH≈1)和碱性(pH>7)条件下,溶胀率均在10倍以上;而在pH=2～6时溶胀较差,当pH=4时出现最低值,溶胀率低于1倍。光学显微镜所观察到的微球粒径均在40μm以内,且大小均匀。采用傅里叶红外光谱仪分析了不同配比样品特征峰的峰值和峰面积的变化。用722光栅分光光度计研究了共聚物微球包埋考马斯亮蓝的溶胀释放过程。     

异佛尔酮二异氰酸酯溶液扩链合成聚乳酸类药物缓释剂

以外消旋乳酸(D,L-LA)直接熔融聚合得到的低相对分子质量聚外消旋乳酸(PDLLA)为原料,通过二异氰酸酯扩链合成了聚乳酸类药物缓释材料。当采用异佛尔酮二异氰酸酯(IPD I)为扩链剂,反应在四氢呋喃溶液中进行时,扩链反应工艺条件为:扩链剂用量n(NCO)∶n(OH)=2∶1时,66℃下回流反应2 h,相对分子质量增加近2.92倍。与2,4-甲苯二异氰酸酯(TD I)扩链法相比,IPD I溶液扩链法不仅提高产物相对分子质量的效果非常接近,具有反应温和、条件易调控等优点,而且使所得聚乳酸类药物缓释材料具有较高的生理安全性。     

聚乳酸耐热改性的研究

研究了一种耐热聚乳酸,并对其进行了红外光谱、示差扫描量热分析、热重分析、X-射线衍射、热收缩及断裂强力等测试。同样条件下,这种耐热聚乳酸的热收缩率是普通聚乳酸的1/4,耐热性有了明显改善,强力略有提高。     

聚乳酸-羟基乙酸聚合物载入羟基喜树碱载药纳米粒子的制备及表征

以抗癌药物羟基喜树碱作为模型药物,可降解材料聚乳酸-羟基乙酸(PLGA)为药物负载体,采用溶剂-抗溶剂沉淀法制备聚乳酸-羟基乙酸/羟基喜树碱的载药纳米微球,考察不同溶剂-反溶剂体系对载药包封效果的影响。结果表明,以丙酮-水为溶剂体系制备的载药微球性能较好,形貌外观呈圆球形,球表面圆润光滑,粒度均一,分散效果良好,平均粒径为160 nm,载药微球包封率随着载药量的增加而减小,实测载药量为7.83%的PLGA载药微球,其载药包封率为87.68%,在28 d后溶出累计量约50%,可见以聚乳酸-羟基乙酸为载体制备的羟基喜树碱剂型,缓释作用良好。     

聚乳酸纤维的静电纺丝及其形态结构研究

采用二氯甲烷为溶剂,以滚筒为收集装置,利用静电纺丝法制备了聚乳酸纳米纤维。分析了溶液体系和滚筒转速对纤维形态结构的影响。结果表明:在质量分数相同的条件下,采用相对分子质量较大的聚乳酸切片所纺纤维直径细而均匀;质量分数增加时,电纺丝产品由一些高分子微/纳米液滴渐变为成形较好、珠状较少的平滑纤维,其平均纤维直径先增加后减小;控制收集滚筒的转速在一定范围内,可以获得排列取向较好的纤维。     

Synthesis,Characterization, and Release Dynamic of Acetylsalicylic Acid From Acetylsalicylic Acid/Poly(vinylalcohol-co-ethylene) Membrane

A series of poly(vinylalcohol-co-ethylene)/acetylsalicylic acid blends (PEVA/AcSa) of different AcSa contents were prepared and characterized by the solubility test, differential scanning calorimetry, and scanning electron microscopic analyses. The results revealed that AcSa was perfectly soluble in PEVA at certain composition and uniformly distributed throughout the polymer matrix. The release dynamic of AcSa from PEVA/AcSa material was studied at body temperature during 92 h in which the influence of AcSa initially incorporated in PEVA, the pH of media, the membrane thickness, and the stability of AcSa release rate on the release dynamic were detailed.     

聚乙烯醇改性固体淀粉胶粘剂的研制

介绍新型固体淀粉胶的制备方法。以淀粉为主要原料，经加热催化分步氧化，再加入聚乙烯醇合成树脂改善其性能，然后用硬脂酸钠作为赋型剂。制得的淀粉胶剪切强度比泡花碱高0.01MPa。     

改性聚天冬氨酸/聚丙烯酸复合吸水性树脂的制备与敏感性研究

以丙烯酸(AA)为单体,过硫酸钾(KPS)为引发剂,改性聚天冬氨酸(MKPAsp)作为交联剂,通过水溶液聚合法制得新型改性聚天冬氨酸/聚丙烯酸(MKPAsp/PAA)复合吸水性树脂。通过红外光谱、热失重分析(TGA)和扫描电镜(SEM)对复合吸水性树脂进行了表征。SEM表明AA的加入,改善了孔道结构,使孔密度增加,孔径更加均匀规则。研究了具有不同组成复合吸水性树脂在不同温度、pH和盐溶液中的溶胀性能,结果表明MKPAsp/PAA复合吸水性树脂低临界溶解温度(LCST)比聚天冬氨酸(KPAsp)提高了10℃,表现出良好的温度敏感性;在pH为6和10的溶液中出现2个吸液峰值;复合吸水性树脂的耐盐性较KPAsp得到了提高,且在不同价态的氯盐中吸液倍率顺序为Na~+Fe~(3+)Ca~(2+)。制得的MKPAsp/PAA复合吸水性树脂在去离子水和90mmol/L的Na Cl溶液中的最佳吸液倍率达到886.7和165.1 g/g,分别比KPAsp树脂提高了3.8倍和2.3倍。     

Reactively Modified Poly(lactic acid): Properties and Foam Processing

Summary: In order to produce modified poly(lactic acid) (PLA) resins for applications requiring high melt viscosity and elasticity (e.g., low‐density foaming, thermoforming), a commercial PLA product has been reactively modified in melt by sequentially adding 1,4‐butanediol and 1,4‐butane diisocyanate as low‐molecular‐weight chain extenders. By varying amounts of the two chain extenders associated to the end group contents of PLA, three resulted samples were obtained. They were then structurally characterized by FTIR spectroscopy and molecular structure analysis. Their thermal, dynamic mechanical thermal properties and melt viscoelastic properties were investigated and compared along with unmodified PLA. The results indicated that chemical modification may be characterized as chain scission, extension, crosslinking, or any combination of the three depending on the chain extender amounts. The increase of PLA molecular weight could be obtained by properly controlling amounts of two chain extenders. The samples with increased molecular weights showed enhanced melt viscosity and elasticity. Such property improvements promised a successful application for modified PLA in a batch foam processing by producing foams with reduced cell size, increased cell density and lowered bulk foam density in comparison with plain PLA foam.

Cellular morphology of a modified PLA foam.     

聚乳酸/聚(已二酸-对苯二甲酸丁二酯)共混物的非等温结晶动力学

采用熔融挤出法制备了聚乳酸/聚(已二酸-对苯二甲酸丁二酯)共混物。利用差示扫描量热仪研究了聚乳酸及其共混体系的非等温结晶过程。用经Jeziorny修正的Avrami方程和Mo法对其非等温结晶动力学进行了分析。结果表明:Avrami方程和Mo法都适用于处理聚乳酸及其共混体系的非等温结晶过程,共混物的结晶速率大于聚乳酸的结晶速率。此外,用Huffman-Lauritzen理论计算了非等温结晶的结晶活化能,发现共混体系的结晶活化能绝对值小于聚乳酸。     

含聚氧乙烯链端树枝状聚（胺-酯）的合成及性能

以端基为8个伯氨基的树枝状化合物〔PAE(NH2)8〕和聚氧乙烯〔PEO-A(454)〕或丙烯酸钠(SAA)与聚氧乙烯为原料合成了含聚氧乙烯链端树枝状聚(胺-酯)(PAE-PEO-A和PAE-SAA-PEO-A)。通过正交实验讨论了反应温度、反应时间及原料配比对产物产率的影响,并用FTIR、1HNMR、13CNMR及GPC对试样进行结构表征。测定了含聚氧乙烯链端树枝状聚(胺-酯)的表面张力及对苯甲酸、水杨酸的增溶性。实验结果表明,当反应温度为65℃,反应时间为96 h,原料的配比量n〔PAE(NH2)8〕∶n[(PEO-A(454)]=1∶16,以甲醇为溶剂,产物产率为88.30%。PAE-PEO-A溶液的临界胶束质量浓度为0.007 5 g/L,最小表面张力为43.8 mN/m。PAE-PEO-A对苯甲酸、水杨酸都有增溶性,且增溶能力随着它们的表面官能团数的增多和浓度的增加而增大。当反应温度为50℃,反应时间为96 h,原料的配比量n〔PAE(NH2)8〕∶n(SAA)∶n〔PEO-A(454)〕=1∶12∶8,以甲醇为溶剂,产物产率为48.83%。PAE-SAA-PEO-A水溶性极好,其表面张力与水接近,几乎不具有表面活性。PAE-SAA-PEO-A对苯甲酸和水杨酸有良好的增溶性,尤其是对水杨酸的增溶性明显。在相同质量浓度0.500 g/L时,PAE-SAAPEO-A对水杨酸的增溶量约为PEG-400的2.4倍。     

羟基保护法制备聚(D-乳酸-葡萄糖)共聚物及其性能研究

以α-D-葡萄糖为原料,采用羟基保护法制备1,2:5,6-双-O-异丙叉基-α-D-呋喃葡萄糖(ODG),并与聚D-乳酸(PDLA)熔融共聚合成聚(D-乳酸-1,2:5,6-双-O-异丙叉基-α-D-呋喃葡萄糖)共聚物(PDLAODG),然后水解脱羟基制备聚(D-乳酸-葡萄糖)共聚物(PDLAG).采用核磁共振氢谱、傅...