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Chitosan-g-PAA Hydrogels for Colon-Specific Drug Delivery: Preparation, swelling behavior and in vitro Degradability

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Journal of Wuhan University of Technology(Materials Science) 2010年第2期25卷 248-251页

作者：龚时琼殷以华 School of Chemistry and Chemical Engineering Huazhong University of Science and Technology Department of Pharmaceutical Engineering School of Chemistry Engineering Wuhan University of Technology

A series of cross-linked hydrogels for colon-specific drug delivery were synthesized by graft copolymerization of Chitosan and acrylic acid using N, N＇-methylene-bis-（acrylamide） as a cross-linker. Their swelling behavior in different pH buffer solutions and colonic enzymatic degradability were studied. The obtained results show that these hydrogels have good pH sensitivity which can avoid drug release in stomach, and their swelling kinetics in stimulant intestinal environment follow second-order swelling kinetics equation. The factors influencing the swelling kinetics include the degree of cross-linking and the composition, which may control no release or a little amount release of drug inside the hydrogels in the small intestine by tailoring these factors. The gels are degradable by colonic enzymes and there is a correlativity between the degradation of networks and the swelling degree of the gels, which may trigger the release of drug in the colon. The hydrogels show a great potential for their application in oral colon-specific drug delivery system.

关键词： hydrogel pH sensitivity swelling behavior colonic enzymatic degradability colon-specific drug delivery

Preparation and swelling behavior of polyvinyl alcohol physiological saline gel

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Journal of Central South University of Technology 2006年第1期13卷 27-31页

作者：潘育松熊党生马如银 Department of Materials Science and Engineering Nanjing University of Science and Technology Nanjing 210094 China

Polyvinyl alcohol(PVA) physiological saline gel was prepared using physiological saline solution of the polymer by freezing and thawing method. The influences of the concentration of PVA, freezing and thawing cycle times and solvent swelling media on the swelling properties of PVA saline gel were investigated. The result show that the electrolytical ions have great effect on the swelling behavior of PVA saline gel. The equilibrium swelling ratio of PVA saline gel in aqueous swelling media is larger than that in saline swelling media. Also, the equilibrium swelling ratios of PVA saline gel in aqueous and in saline media decrease with the increase of gel concentration and the increase of freezing and thawing cycle times. The decreasing speed of equilibrium swelling ratio with the increase of freezing and thawing cycle times of PVA gel in distilled water is faster than that in physiological saline. The swelling kinetic equation can sufficiently describe the swelling behavior of PVA physiological saline gel.

关键词： freezing and thawing polyvinyl alcohol saline gel swelling behavior

Research on swelling behavior of HPC/PAN Films

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Research on Swelling Behavior of HPC/PAN Films

Preparation and properties of physically and chemically cross-linked hybrid hydrophobic association hydrogels with good mechanical strength

绿色纺织，健康生活——第三届纺织生物工程及信息学国际会议

作者： Hui Li1, Xiao-Yan Li2, Xiao-Ning Yan3 1Key Laboratory of Aids Chemistry and Technology for Light Chemical Industry, Ministry of Education, College of Resource and Environment, Shaanxi University of Science and Technology, Xi’an 710021, China 2Clothing and Art Design College, Xi’an Polytechnic University, Xi’an 710048, China 3Xi’an Aerospace Propulsion Testing Technique Institute

A series of thermo-sensitive blending films were prepared from hydroxypropylcellulose and polyarcylonitrile. The effects of materials ratio, pH value and temperature on these blended films swelling velocity were characterized. As temperature was lower than LCST, different results are found while dipping blend films samples in acid or base condition respectively. Results from pH value was 1.4 which showed that swelling velocity of HPC/PAN blending films increased with the addition of HPC, film’s swelling was mainly controlled by polymer chain relaxation. But, it was controlled by water molecules diffusion under pH value of 7.4. swelling velocity was also effected by both temperature and pH value.

关键词： hydroxypropylcellulose polyarcylonitrile swelling behavior

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Science China Chemistry 2016年第3期59卷 282-292页

作者： Guoqing Jiang Li Huang Bo Li Quan Zhou Zhiying Li Enhanced Oil Recovery Laboratory Exploration and Development Research InstituteDaqing Oilfield Company LimitedDaqing163712China State Key Laboratory of Enhanced Oil Recovery Petrochina Research Institute of Petroleum Exploration&DevelopmentBeijing100083China Production Engineering&Research Institute Daqing Oilfield Company LimitedDaqing163453China College of Chemistry Jilin UniversityChangchun130012China

To correct the defects of hydrophobic association hydrogels （HA-gels）, new physically and chemically cross-linked hybrid hy- drophobic association hydrogels （hybrid HA-gels） were prepared by radical copolymerization of acrylamide （AM）, octylphe- nol polyoxyethylene （n） acrylate （OPnAC, n stands for the number of ethoxy group, and is 10 and 21） and N,N＇-methylene- bisacrylamide （MBA）. On the basis of the statistical molecular theory of rubber elastic, the Mooney-Rivlin model and using the tensile true stress （O＇true） tested at room temperature, the number of network strands per unit volume （o~） and the num- ber-average molar mass of a network strand （Me） were evaluated for hybrid HA-gels. For the hydrogels, the effect of the con- tent of MBA and OP10AC on their tensile mechanical properties was studied by using o0 and Mc; also, the effect of the com- positions and temperature on their swelling behavior in distilled water was discussed in detail. In addition, hybrid HA-gels in- cluding a small quantity of MBA possessed the capabilities of secondary self-healing and remolding. In contrast with HA-gels prepared by the same compositions besides MBA, hybrid HA-gels showed good mechanical strength and long-term thermal stability in distilled water in the range of 25 to 80℃. Furthemore, hybrid HA-gels also avoided the self-deswelling behavior of HA-gels. The results show that the application fields of HA-gels will be greatly broadened after introducing a chemical cross-linking network.

关键词： hydrophobic association hydrogels hybrid hydrogels mechanical properties swelling behavior reforming capability

Sintering mechanism of Cu-9Al alloy prepared from elemental powders

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Progress in Natural Science:Materials International 2019年第4期29卷 425-431页

作者： Zhenghua Deng Haiqing Yin Cong Zhang Guofei Zhang Tong Zhang ZiKui Liu Haibao Wang Xuanhui Qu Collaborative Innovation Center of Steel Technology University of Science and Technology Beijing Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and Technology University of Science and Technology Beijing Department of Materials Science and Engineering The Pennsylvania State University Chongqing Engineering Technology Research Center for Light Alloy and Processing Chongqing Three Gorges University

The sintering behavior of Cu-9A1 alloys prepared from die pressing of elemental powders was *** experimental results and kinetic analysis showed the formation of three consecutive layers of Al;Cu,Al;Cu;,and AlCu phases,with Al;Cu appearing first in the initial solid phase sintering stage.A liquid phase formed in the intermediate stage,resulting from the eutectic reaction between A1 and Al;Cu phases at 500℃,which is 47℃lower than the equilibrium reaction *** occurred when the liquid phase infiltrated the gaps between the copper particles,leaving pores at the original sites of A1 particles and Al;*** the final stage of sintering,the Al-rich phases（Al;Cu and AlCu） transformed to Al-poor phases（Al;Cu;and a-Cu） in the temperature range of 500-565℃.Al;Cu;and a-Cu then transformed to AlCu;（β） above the eutectoid reaction temperature（565℃）,whereas AlCu;transformed to a-Cu and eutectoid phases（α-Cu+Al;Cu;） during *** pure copper transformed to AlCu;) and the pore volume decreased at 1000℃.The microstructure study helps manipulate precisely the sintering process of Cu-Al alloys and optimize the microstructure with a high dimensional accuracy.

关键词： Cu-9Al alloy Liquid phase sintering swelling behavior Diffusion

Dynamic Properties of Polyampholyte Hydrogel Elucidated by Proton NMR Spin-spin Relaxation Time

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Chemical Research in Chinese Universities 2013年第6期29卷 1203-1207页

作者： LU Cui-ge XU Kun LI Wen-bo LI Peng-chong TAN Ying WANG Pi-xin Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied Chemistry Chinese Academy of SciencesChangchun 130022 P.R.China Graduate University of Chinese Academy of Sciences Beijing 100049 P.R.China

1H spin-spin relaxation time（T2） measurement of polyampholyte hydrogel poly（methylacrylic acidacryloyloxyethyl trimethylammonium chloride）[P（MA-DAC）] in different pH, ionic strength and temperature was carried out to reveal the molecular mobility. Spontaneous volume transition of the polyampholyte hydrogel was also investigated by spin-spin relaxation time measurement. Meanwhile T2 and the proton component fraction were acquired to study the swelling behaviour of the hydrogel. Moreover the changes of T2 characterized the molecular mo- bility of polyampholyte hydrogel in various swelling states. And the results suggest that the mobility of the main chains and a few free side chains（the long T2） of P（MA-DAC） was dominated by the mesh size in the hydrogel net- work, depending on the swelling ratio（Q） and the mobility of the side chains（the short T2） was influenced by electrostatic interaction between different charges in polymer side chains. Finally the T2 measurements of P（MA-DAC） hydrogel in the spontaneous swelling-deswelling process demonstrated the electrostatic interaction of the charged side chains caused deswelling behavior. At the same time, the mobility state transition temperature of the charged side chains was also studied by the lH spin-spin relaxation time measurements, and the transition activation energy of the side chains is 2.72 kJ.

关键词： Spin-spin relaxation time Molecular mobility Polyampholyte hydrogel swelling behavior