刺激响应性聚合物纳米胶束在药物控释中的应用研究

聚合物纳米胶束不仅可以提高药物的溶解度、生物利用度,延长药物在人体内的循环时间,还可以有效控制药物的释放而实现靶向治疗效果,极大地减少药物对人体的副作用。通过嵌段共聚物的纳米工程,可制备出具有细胞或组织靶向性且对物理或化学刺激敏感的高分子药物载体。本文综述了对pH值、温度、超声波和光具有响应性的聚合物纳米胶束的制备及其在药物控制释放领域的应用。     

刺激响应型药物释放体系的研究进展

刺激响应型聚合物在药物释放领域的应用越来越广泛,研究也越来越受到重视.根据不同类型的刺激条件,综述了pH响应型、温度响应型、葡萄糖响应型、场响应型等一系列刺激响应型药物释放体系的应用和研究进展.     

Stimuli‐responsive molecularly imprinted hybrid polymer gel as a potential system for controlled release

The purpose of this study is to develop a stimuli‐responsive hybrid polymer gel system with an improved mechanical stability as a controlled drug delivery carrier that can undergo phase transition by the stimulation of ethanol–water mixture. For this aim, trimethoxysilane terminated poly(propylene glycol) by coupling of 3‐isocyanatopropyl‐triethoxysilane with the hydroxyl end groups of poly(propylene glycol) through urethane bonds was synthesized. Hybrid polymer gels prepared in the presence of tryptophan (Trp), as a model of drug, were characterized and gelation time of polymer network was obtained by monitoring the fluorescence emission of Trp in pre‐gel solution. Swelling, solvent uptake and release kinetic of polymer gels were evaluated depending on time. The diffusional exponents (n) and diffusion constants (k) of each gel were calculated by using the swelling kinetic data. The effect of precursors as a monomer on Trp release profile was analyzed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42913.     

Preparation of superabsorbent polymer with slow‐release phosphate fertilizer

A superabsorbent polymer with slow‐release phosphate fertilizer was prepared by esterification of polyvinyl alcohol (PVA) and phosphoric acid (H₃PO₄), which was a slow‐release fertilizer at the same time. The product's water absorbency (WA) was about 480 times its own weight if it was allowed to swell in distilled water at room temperature for 24 h. WA under various conditions, such as varying the reaction time, the amount of sodium carbonate (Na₂CO₃), the reaction temperature, and the concentration of phosphoric acid ([H₃PO₄]), were investigated and optimized. The optimal sample of the product was characterized by FTIR and elemental analysis. The results showed that phosphoric groups had grafted on PVA molecule chains, and the content of P₂O₅ in the product was 31.2%. The water retention property and phosphate slow‐release mechanism of the product were studied as well. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3417–3421, 2004     

Drug transport in stimuli responsive acrylic and methacrylic interpenetrating polymer networks

The interpenetrating polymer networks (IPNs) are recently gaining attention as sustained drug delivery systems because they could ensure a proper combination of functionality and network density to control the drug release profiles. This study aims to reveal how the functionality of two IPNs based on polyacrylamide and respectively poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA) influences their smart behavior as well as their properties as delivery systems of the cationic drug verapamil hydrochloride (VPM). The “extra” α‐methyl group of PMAA results into a loss of the temperature sensitivity in the studied region and changes the pH responsivity of the PMAA/PAAM IPNs as compared to the PAA/PAAM IPNs. Moreover, the VPM diffusion in both IPNs depends on their composition due to the change in their functionality as well as of their network density. The “extra” α‐methyl group of PMAA defines its enhanced hydrophobicity and hence influences the VPM diffusion mechanism. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45380.     

Dual responsive polymeric bionanocomposite gel beads for controlled drug release systems

Scientists are searching potential solutions for cancer treatments as well as ways to avoid the side effects of anti‐cancer agents, via targeted drug delivery. The aim of this research is to propose dual responsive beads based on sodium alginate (SA), methylcellulose (MC), and magnetic iron oxide nanoparticles (MIONs) for controlled release of 5‐Fluorouracil (5‐FU) as model drug. The beads were prepared by the dual crosslinking of SA and MC in the presence of MIONs. The structural, thermal, morphological, magnetic characteristics as well as the release profile of 5‐FU were studied. The characterization results showed that the drug molecules and MIONs were well dispersed in the polymeric matrix. The cumulative release percentage was ca. 80% at pH = 4.2 and 40% at pH = 7.2 after 6 h. Thus, the sensitivity of beads on the pH value was verified. Moreover, the release profile exhibited reduction with an increase in the concentration of MIONs under an external magnetic field. The obtained results confirmed the dual sensitive release of 5‐FU (i.e., PH/magnetic) that can be used for the targeted and controlled drug delivery systems. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45143.     

Biocompatible polymer nanoparticles for intra-cellular applications

Polymeric styrene microspheres have a great potential at the interface of chemistry and biology. The progress of the synthetic development of multifunctional microspheres and their use as delivery agents of different biomolecules into cells is discussed. Their multifunctional properties open a wide range of applications from intracellular real-time sensors, to the use of microspheres as catalysts performing exogenous chemistry within cells.     

Composite chitosan/poly(ethylene oxide) electrospun nanofibrous mats as novel wound dressing matrixes for the controlled release of drugs

The aim of this study was to develop novel biomedical electrospun nanofiber mats for controlled drug release, in particular to release a drug directly to an injury site to accelerate wound healing. Here, nanofibers of chitosan (CS), poly(ethylene oxide) (PEO), and a 90 : 10 composite blend, loaded with a fluoroquinolone antibiotic, such as ciprofloxacin hydrochloride (CipHCl) or moxifloxacin hydrochloride (Moxi), were successfully prepared by an electrospinning technique. The morphology of the electrospun nanofibers was investigated by scanning electron microscopy. The functional groups of the electrospun nanofibers before and after crosslinking were characterized by Fourier transform infrared spectroscopy. X‐ray diffraction results indicated an amorphous distribution of the drug inside the nanofiber blend. In vitro drug‐release evaluations showed that the crosslinking could control the rate and period of drug release in wound‐healing applications. The inhibition of bacterial growth for both Escherichia coli and Staphylococcus aureus were achieved on the CipHCl‐ and Moxi‐loaded nanofibers. In addition, both types of CS/PEO and drug‐containing CS/PEO nanofibers showed excellent cytocompatibility in the cytotoxicity assays. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42060.     

聚合物乳液包膜控释肥料技术研究进展

综述了包膜控释肥料聚合物乳液包膜剂的研究现状和基本特性,分析了流化床和转鼓流化床包膜过程中的主要影响因素,对目前聚合物乳液包膜控释肥料的释放性能进行了评述,分析了乳液包膜控释肥料研发中的关键问题,并对其发展前景进行了展望。     

Sustained release of CIP from TiO2-PVDF/starch nanocomposite mats with potential application in wound dressing

Electrospinning is an economical and alluring method to fabricate wound dressing mats from a variety of natural and synthetic materials. In this study, polyvinylidene fluoride (PVDF) and starch composite mats containing ciprofloxacin (CIP) loaded on titanium dioxide nanoparticles (TiO₂) were prepared. Fourier Transform Infrared spectra of CIP, synthesized TiO₂ NPs, TiO₂/CIP, and PVDF/starch composite mats are analyzed. Scanning electron microscopy images revealed that the fiber diameter of PVDF nanofibers thickens by increasing starch, which varies between 180 nm and 550 nm. Strain at break of PVDF, starch, PVDF/starch (2:1 w:w; P2S1), PVDF/starch (1:1 w:w; P1S1), PVDF/starch (1:2 w:w; P1S2), and nanofibers were 103 ± 11, 3 ± 0.6, 27 ± 4, 52 ± 5.2, 7.7 ± 1%, respectively. Based on strain at break and young modulus, P2S1 was selected as a suitable candidate for wound dressing to which load TiO₂/CIP as a bioactive agent. The release rate of CIP showed that about 40% of the drug is released in the first 2 days. Furthermore, the antibacterial activity of dressings was investigated using Escherichia coli and Staphylococcus aureus microorganisms and zones of clearance were obvious around the specimen on the agar plate. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48916.     

A novel honey‐based nanofibrous scaffold for wound dressing application

In this study, nanofiber meshes were produced from aqueous mixtures of poly(vinyl alcohol) (PVA) and honey via electrospinning. The Electrospinning process was performed at different PVAs to honey ratios (100/0, 90/10, 80/20, 70/30, and 60/40). Dexamethasone sodium phosphate was selected as an anti‐inflammatory drug and incorporated in the electrospinning solutions. Its release behavior was determined. Uniform and smooth nanofibers were formed, independent of the honey content. In case honey content increased up to 40%, some spindle‐like beads on the fibers were observed. The diameter of electrospun fibers decreased as the ratio of honey increased. The release characteristics of the model drug from both the PVA and PVA/honey (80/20) nanofibrous mats were studied and statistical analysis was performed. All electrospun fibers exhibited a large initial burst release at a short time after incubation. The release profile was similar for both PVA and PVA/honey (80/20) drug‐loaded nanofibers. This study shows that an anti‐inflammatory drug can be released during the initial stages and honey can be used as a natural antibiotic to improve the wound dressing efficiency and increase the healing rate. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci, 2013     

Poly(vinyl alcohol)/chitosan/honey/clay responsive nanocomposite hydrogel wound dressing

Many efforts have been made to develop modern wound dressings to overcome limitations of traditional ones. Smart nanocomposite hydrogels are appropriate candidates. In this work, a novel responsive nanocomposite hydrogel based on poly(vinyl alcohol)/chitosan/honey/clay was developed and evaluated as a novel wound dressing. The morphology and properties of synthesized nanocomposite hydrogels loaded with honey as a drug model were investigated. The exfoliated morphology of nanocomposite was confirmed by X‐ray diffractometry. Swelling studies were performed at 20 and 37 °C at various pH. The results showed that swelling increased as a result of temperature rise and maximum swelling occurred at a pH of 2. In vitro release of honey was also studied at the same conditions. Corresponding results indicated faster honey release rate at higher pH values. MTT results exhibited no cytotoxicity in nanocomposite hydrogel system. Investigation of antibacterial activity revealed more than 99% antibacterial activity for proposed system. In vivo results confirmed the wound healing ability of developed system. Generally, appropriate properties of proposed system made it ideal in wound dressing applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46311.     

卫生用高吸水性树脂的生产及市场前景

介绍了国内外高吸水性树脂（SAP）的生产和市场发展前景,详细叙述了在卫生用品方面的市场需求情况。简述了SAP的生产技术及其生产工艺,并介绍了国内外有关SAP的技术发展趋势。在我国,由于卫生用品（婴儿尿布、成人失禁垫、妇女卫生巾等）的普及水平不断提高,SAP消费量每年以两位数的速度增长,市场前景广阔。     

Controlled release of organic substances using polymer membrane with responsive function for amino compounds

In order to regulate the release of a water-soluble organic substance from a polymer device, an amphiphilic polymer membrane having a dinitrophenyl group was prepared and the effects of an amino compound on the release of such a substance in an aqueous medium were investigated. When the amino compound, triethylamine (TEA), was added to the medium, the release rate of methyl orange (MO) in solution from the polymer device increased; the same was noted with an increase in the concentration of TEA. However, on removal of the TEA from solution, the rate resumed its initial level of that in water. These results were explained by the change in the swelling degree of the polymer membrane induced by the addition of TEA. This change was considered to result from the formation of a charge transfer complex between the dinitrophenyl group in the polymer membrane and the added TEA, since a charge transfer spectrum was observed in the polymer membrane–TEA system.     

Thermo‐ and pH‐responsive microgels for controlled release of insulin

Microgel particles were prepared, made of hydroxypropylcellulose‐graft‐(acrylic acid) (HPC‐g‐AA) and acrylic acid(AA). The particles undergo reversible volume phase transitions in response to both pH and temperature changes while keeping the inherent properties of PAA and HPC‐g‐AA. Dynamic light scattering measurements reveal that the average hydrodynamic radius and hydrodynamic radius distributions of the microgel particles depend on temperature and pH. The microgels exhibit excellent pH sensitivity and a higher swelling ratio at higher pH in aqueous solution. In vitro release study shows that the amount of insulin released from the microgels is less at pH = 1.2 than at pH = 6.8. The results indicate that the resultant microgels seem to be of great potential for intelligent oral drug delivery. Copyright © 2012 Society of Chemical Industry     

Magnetic field responsive methylcellulose-polycaprolactone nanocomposite gels for targeted and controlled release of 5-fluorouracil

5-Fluorouracil loaded magnetic field sensitive methylcellulose and polycaprolactone gels were prepared and characterized by FTIR, XRD, TGA, SEM, and VSM. Swelling analysis supplied important information on drug diffusion properties. The release profile of gels was investigated in different buffer solutions and the highest release values were observed at pH = 7.2. Release kinetic was analyzed using an empirical equation to clarify the transport properties of drug. The effects of nanoparticle concentration and applying external magnetic field were investigated on release profile. The results indicated that the drug release decreased by both, applying external magnetic field and increasing the concentration of Fe₃O₄ nanoparticles.     

超吸水材料的研究进展

超吸水材料具有吸水倍数高、保水能力强、外观柔软、内部呈多孔网状结构等优点,但存在对含电解质水溶液吸收能力有限的问题。本文首先分析了超吸水材料的吸附机理,在此基础上着重介绍了超吸水树脂、超吸水纤维、超吸水膜、超吸水织物基气凝胶吸水材料的制备原理与特点,其次概述了不同形式吸水材料对去离子水、盐水、合成尿、尿素的吸附机理差异,指出增加吸水材料的比表面积、亲水基团数量、分子量,适当的交联度和中和度,并结合高的渗透压、静电排斥力、额外添加无机粒子可提高吸液能力,随后简述了高分子气凝胶与纺织品相结合构筑超吸水织物在安全防护领域的应用情况,最后对超吸水材料的可增长点进行了展望,以期为提高超吸水材料对含电解质水溶液的吸收能力提供理论参考和技术支持。     

Simultaneous and sequential micro-porous semi-interpenetrating polymer network hydrogel films for drug delivery and wound dressing applications

Novel semi-interpenetrating polymer networks (so-called simultaneous SIPNs) of various compositions were synthesized using segmented polyurethane urea (SPUU), N-isopropylacrylamide (NIPAM), acrylic acid (AA), and butylmethacrylate (BMA), resulting in an SIPN film denoted as SPUU/poly(NIPAM-co-AA-co-BMA). The resulting simultaneous SIPN films were neutralized by exposure to pH 7.4 phosphate buffer solution (PBS). The neutralized films were dried and then characterized by differential scanning calorimetry (DSC). The DSC results showed that the T_g of the SIPNs depends mostly on SPUU content and on the composition of the acrylate monomers. PNIPAM was incorporated as a second network in one composition of simultaneously prepared SIPN film through a sequential polymerization method (so-called sequential SIPNs). Both simultaneous and sequential SIPN films were examined by scanning electron microscopy (SEM) after freeze drying at their equilibrium states. The SEM study revealed that simultaneous SIPNs had a porous morphology in the absence of BMA, but the porosity disappeared at higher BMA content. The morphology of the sequential SIPN film was almost similar to that of pure PNIPAM. Finally, simultaneous and sequential SIPNs were used for swelling and drug release studies at different pH values and at different temperatures to determine the environmental sensitivity of these gels. Simultaneous SIPNs absorbed more water than sequential SIPNs, but both had a poor rate of water absorption at pH 1.2. In the drug release study, a higher thermosensitivity was observed for sequential SIPNs than for simultaneous SIPNs.     

Creation of dense polymer brush layers by the controlled deposition of an amphiphilic responsive comb polymer

We introduce a copolymer with a comb topology that has been engineered to assemble in a brush configuration at an air-water interface. The molecule comprises a 6.1 kDa poly(methyl methacrylate) backbone with a statistical amount of poly[2-(dimethyl amino)ethyl methacrylate] polybase side chains averaging 2.43 per backbone. Brush layers deposited with the hydrophobic PMMA backbone adsorbed to hydrophobized silicon are stable in water even when stored at pH values less than 2.0 for over 24 h. The use of a Langmuir trough allows a simple controlled deposition of the layers at a variety of grafting densities. Depth profiling of brush layers was performed using neutron reflectometry and reveals a significant shifting of the responsiveness of the layer upon changing the grafting density. The degree of swelling of the layers at a pH value of 4 (below the pK_b) decreases as grafting density increases. Lowering the pH of the subphase during deposition causes the side chains to become charged and more hydrophilic extending to a brush-like configuration while at neutral pH the side chains lie in a “pancake” conformation at the interface.     

Poly(L-lactide-co-caprolactone)/collagen electrospun mat: Potential for wound dressing and controlled drug delivery

Here we report a novel bioactive electrospun mat based on poly(L-lactide-co-caprolactone) (PLLC) and collagen for wound dressing and sustained drug delivery of gentamicin. PLLC/collagen electrospun mat loaded with 10% gentamicin showed bioactivity for 15 days against Gram-positive and Gram-negative bacteria. The in vitro cell culture of 3T3 fibroblasts confirmed that these electrospun mat provide an increased specific interface area and hydrophilicity to enhance cell attachment, proliferation, and migration. The modified PLLC/collagen mat provided an excellent enhancement in properties of antibacterial wound dressings with a minimum in vitro toxicity and high potency for promoting wound healing stages.