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1.
A new mucoadhesive polymer was prepared by template polymerization of acrylic acid in the presence of poly(ethylene glycol) (PEG). FTIR results indicated that a polymer complex was formed between poly(acrylic acid) (PAA) and PEG through hydrogen bonding. The hydrogen bonding in the PAA/PEG polymer complex was stronger than that in the PAA/PEG blend, and became stronger as the molecular weight of PEG increased. Glass transition temperatures (Tg) of PAA in the PAA/PEG polymer complexes was shifted to a lower temperature than that of PAA in the PAA/PEG blend. However, they tended to become higher as the molecular weight of PEG increased. The dissolution rate of the PAA/PEG polymer complex was much slower than the PAA/PEG blend, and was dependent on pH and molecular weight of the PEG. The mucoadhesive force of the PAA/PEG polymer complexes was stronger than for the PAA/PEG blend or a commercial product, Carbopol 971P NF. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2749–2754, 1999 相似文献
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A new mucoadhesive polymer was prepared by template polymerization of acrylic acid using poloxamer as a template polymer. FTIR results showed that the interpolymer complex was formed by hydrogen bonding between the carboxyl group of poly(acrylic acid) (PAA) and the ether group of poloxamer. The extent of hydrogen bonding in the PAA/poloxamer interpolymer complex increased as the ratio of PAA/poloxamer decreased. The Tg of PAA/poloxamer interpolymer complexes was matched well with the Tg calculated by Gordon‐Taylor's equation than that of their blends. This result suggests that the PAA and poloxamer in the interpolymer complexes are more compatible than their blends. The dissolution rate of PAA/poloxamer interpolymer complexes was much slower than that of their blends, and was dependent on the pH of the medium and the ratio of PAA/poloxamer. The adhesive bond strength of PAA/poloxamer interpolymer complexes to a plastic (polypropylene) plate was greater than their blends or a commercial product, Carbopol 971P NF. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1525–1530, 2001 相似文献
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A novel mucoadhesive polymer was prepared by template polymerization of acrylic acid in the presence of sericin for a transmucosal drug‐delivery (TMD) system. FTIR results indicated that a polymer complex was formed between poly(acrylic acid) (PAA) and sericin through hydrogen bonding. The glass transition temperatures (Tg's) of sericin and PAA in the PAA/sericin polymer complex were inner‐shifted compared with the Tg's of sericin and PAA themselves. This may be due to the increased miscibility of PAA with sericin through hydrogen bonding. The dissolution rate of the PAA/sericin interpolymer complex was dependent on the pH. The mucoadhesive force of the PAA/sericin polymer complex was similar to that of a commercial product, Carbopol 971P NF. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 274–280, 2001 相似文献
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The main aim of the present investigation is synthesis of drug‐grafted poly(vinyl alcohol) (PVA) for sustainable drug release in order to avoid bulk release and unwanted side effects. Here, the PVA was structurally modified with five different drug molecules in DMSO medium at 85 °C under N2 atmosphere for 2 h. The structure of modified PVA was confirmed by FTIR and 1H NMR spectra and further it was characterized by TGA, DSC, and SEM. The tensile strength and % elongation for the structurally modified PVA were determined. The FTIR spectrum showed peaks corresponding to the C?O and C? S stretching due to the grafted drug molecules. The 1H NMR spectrum showed the acrylic CH2 proton signal of PVA around 1.6 ppm. The SEM showed different surface morphology for the structurally modified PVA. The mechanical properties of the structurally modified PVA was found to be reduced due to the presence of traces of solvent molecules and the breaking of inter‐ and intramolecular hydrogen bonding. The sustainable drug release through hydrolysis mechanism was tested at the pH of 7.3. Generally, the drug release followed the Korsmeyer–Peppas model with Fickian drug transportation mechanism except Furosemide (Fur)‐grafted PVA system at the pH of 7.3. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46620. 相似文献
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Diffusion of dichloromethane in poly(lactide‐co‐glycolide) (PLGA), the rate‐limiting step in the later stages of drying of microparticles formed in common encapsulation processes, was studied by the step‐change sorption technique in a dynamic vapor sorption apparatus. Methods were developed to create films of polymer with the appropriate thicknesses for accurate diffusion determination over a wide range of solvent composition. Mutual diffusivities were measured at 5, 25, and 35°C from 10 to 70 wt % solvent. Values range from 2 × 10?10 m2/s at high solvent compositions to as low as 1 × 10?13 m2/s at solvent compositions just above the glass transition of the mixture. Equilibrium sorption isotherms were measured in the same apparatus and agreed favorably with Flory‐Huggins theory using a value of χ = 0.31. The glass transition temperatures of the system were measured over the range of 0–11 wt % solvent content by modulated differential scanning calorimetry. The composition dependence was fit to the Fox equation, which estimated values of the pure polymer and the solvent Tg to be 39.3 and ?131°C, respectively. These values, along with the diffusivity data, were used to deduce the free‐volume parameters specific to PLGA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
6.
Poly(vinyl pyrrolidone) (PVP)/poly(acrylic acid) (PAA) interpolymer complexes were prepared, in ethanol or dimethylformamide (DMF), by template polymerization of acrylic acid in the presence of PVP (MW: 42.5 or 1100 K) used as the template. FTIR analysis showed that the complexes were formed through hydrogen bonding between the carboxyl groups of the PAA and the carbonyl groups of the PVP. The glass‐transition temperature (Tg) of the complex, prepared in ethanol, was higher than that of the component polymers, whereas the Tg of the complex, prepared in DMF, was located between that of the component polymers. The dissolution rate of the complex was affected by the molecular weight of the PVP and the reaction solvent. The release rate of ketoprofen from the complexes showed a pH dependency, and was slower at a lower pH. The ketoprofen release rate from the complex was controlled mainly by the dissolution rate of the complex above the pKa of PAA (4.75) and by the diffusion rate below the pKa. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2390–2394, 2004 相似文献
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The use of poly(lactic acid) (PLA) for controlled drug delivery applications was limited by unfavorable physical properties such as hydrophobicity, high intrinsic crystallinity, low permeability, and high glass transition temperatures. This research used polyethylene glycols (PEGs) of varying molecular weights (300–18,500 g/mol) and concentrations (0–50% w/w) to modify the permeability, intrinsic crystallinity, glass transition temperature, residual solvent levels, and release of a model drug, 5‐flurouracil (5FU), from monolithic films and microcapsules fabricated with PLA. The films were fabricated by solvent casting from methylene chloride. The microcapsules were formed by a coacervation method by using a methylene chloride/hexane solvent/nonsolvent system. Compared to PLA films, all PLA : PEG films showed the following: (1) a glass transition temperature between 40 and 55°C, (2) 5–8% lower residual solvent levels, and (3) enhanced permeability to 5FU. These results suggested that the incorporation of PEG improves the physical properties of PLA films to enable fabrication of controlled release delivery systems. Similar to the films, incorporation of PEG also enhanced the permeability of PLA microcapsules to 5FU. However, high intrinsic crystallinity, dual endothermal character for PLA melting, and significant burst release of 5FU in PLA : PEG microcapsules may limit their development for controlled drug delivery applications. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2025–2030, 2004 相似文献
8.
Among the different approaches to achieve protein delivery, the use of polymers, especially biodegraded, holds great promise. This work aimed to study the preparation and protein release of a novel drug‐delivery system based on human serum albumin (HSA) encapsulated into biodegradable polymer microspheres. The microspheres containing HSA were elaborated by the solvent‐extraction method based on the formation of multiple w/o/w emulsion. The encapsulation efficiency (E.E.) of HSA was determined by the CBB method. Alginate/alginate and calcium chloride was added into an internal aqueous phase to investigate the protein loading efficiency, protein stability, and in vitro release profiles. Microspheres were characterized in terms of their morphology, size distribution, loading efficiency, and in vitro protein release. SDS–PAGE results showed that HSA kept its structural integrity during the encapsulation and release procedure. In vitro studies indicated that the microspheres with alginate added in the internal aqueous phase had a smaller extent of burst release. In conclusion, the work presents a new approach for macromolecular drugs (such as protein drugs, vaccines, and peptide drugs) delivery. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 778–784, 2002; DOI 10.1002/app.10327 相似文献
9.
Polymers have played a vital part in the development of drug delivery systems (DDS). For DDS, having a controllable diameter and distribution are conducive to reproducibility of drug release behavior and efficacy. In this work, an ibuprofen prodrug (Ibu@PMMA) was synthesized by methyl methacrylate (MMA), ibuprofen monomer (Ibu@HEMA), and ethylene glycol dimethacrylate (EGDMA) via emulsion polymerization. The Ibu@PMMA exhibits spherical shapes, and its structural properties were characterized by NMR, FTIR, and SEM techniques. In addition, the hydrodynamic diameter and polydispersity index (PDI) of Ibu@PMMA were reduced by increasing the proportion of emulsifier. Meanwhile, by increasing the amount of initiator, the hydrodynamic diameter and PDI of Ibu@PMMA were decreased. Moreover, Ibu@PMMA exhibits good sustained-release ability in vitro, which could be used as a potential delivery system for anti-inflammatory agents. 相似文献
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A facile thermoresponsive injectable hydrogel is prepared from stearyl methacrylate (SMA) and N-isopropyl acrylamide (NIPAM) copolymers via reversible addition-fragmentation chain-transfer (RAFT) emulsion polymerization method. By regulating the content of the oil phase, emulsions with divergent properties are obtained. The yield stress and the viscosity results of the emulsions increase evidently as the initial content of the oil phase increase from 10 to 40%. The microstructures of 10% oil content sample (SN10) is seen as a dispersed particle whereas 20, 30, and 40% oil content samples (SN20, SN30, and SN40) appear as aggregated particles in a dilute solution that shows the microscopical phase transitions of the emulsions. Increasing the temperature from 15 to 45 °C, phase separation takes place, the emulsions contract to squeeze the water. A sharp decrease in particle size is noticed when the temperature increase from 30 to 35 °C. In this point, hydrophilic drug procaine is loaded and release experiments are conducted using thermoresponsive injectable hydrogel. The drug loading and release results are evaluated using the Weibull distribution model and the Fick's law of diffusion that precisely works out. A thermoresponsive injectable hydrogel offers an efficient, cost-effective, and scalable approach towards controlled release of drugs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48669. 相似文献
12.
The use of polymeric materials as the carrier in the controlled release of guest molecules has become an important research area in the polymeric materials science, because of their advantages of the safety, efficacy and patient convenience. One of them, star amphiphilic polymer can self‐assemble into supermolecular structure (polymer micelles) by the balance of hydrophilic and hydrophobic interaction. In this study, star amphiphilic copolymer consisting of hydrophobic and biodegradable poly(ε‐caprolactone) (PCL) and hydrophilic poly(ethylene oxide) (PEO) blocks were synthesized by two‐step ring‐opening polymerization. The resultant polymer was characterizated by FTIR, 1H‐NMR, and DSC to determine its chemical structure. The morpholoy of the polymer micelles was analyzed by TEM. Using star‐PCL‐b‐PEO as carriers and congo red as model guest molecules, the encapsulation and release properties were investigated by UV–visable analysis. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
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Xiangxiang Du Guohua Jiang Lei Li Wentong Yang Hua Chen Yongkun Liu Qin Huang 《应用聚合物科学杂志》2016,133(9)
Glucose‐sensitive and fluorescence copolymer micelles were designed and prepared via a combination of photoinitiated polymerization and enzymatic transesterification. The water‐soluble photoinitiator and emulsifier 2‐oxooctanoic acid self‐polymerized dimer molecules under UV irradiation were characterized by mass spectrometry. The fluorescence dye (9‐anthracene alcohol) and biocompatible hydrophilic chains [poly(ethylene glycol)] were introduced to the polymer chains during the photopolymerization and enzymatic transesterification processes. The as‐prepared copolymers were confirmed by 1H‐NMR spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and dynamic light scattering. The resulting copolymers exhibited excellent glucose sensitivity and stability against protein. The optical fluorescence properties of the copolymer micelles were investigated with fluorescence spectrophotometry, fluorescence microscopy, and confocal laser scanning microscopy. Because of the amphiphilic feature, the micelles could be self‐assembled and used to load insulin. The controlled release of insulin was evaluated and was triggered by glucose in vitro. This study provided a new strategy for fabricating functional carriers as self‐regulated insulin‐release systems. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43026. 相似文献
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A new class of PLGA‐based materials suitable for the production of biodegradable NPs via free‐radical polymerization is proposed. ROP of lactide and glycolide using HEMA is carried out; macromonomers (HEMA‐LxGyA) with short PLGA chain ends are successfully produced. Afterwards, monomer‐starved semi‐batch emulsion polymerization of these HEMA‐LxGyA macromonomers is performed to obtain NPs with a low polydispersity index and a controlled size. The stability and degradability of NPs is confirmed from degradation studies that verify the possibility of tuning the degradation time by changing macromonomer characteristics such as chain length and composition.
16.
An efficient protocol for the synthesis of polymer–gemcitabine conjugates with variable composition and potential hepatoma‐targeting property was achieved by combining selectively enzymatic transesterification with radical polymerization. Four polymerizable vinyl gemcitabine esters were first prepared by highly selective transesterification of gemcitabine with divinyl dicarboxylates using CAL‐B as catalyst in acetone and characterized by IR, 1H‐NMR, 13C‐NMR, and ESI‐MS. The effects of enzyme sources, organic solvents, and molar ratio of substrates on the enzymatic transesterification were investigated in detail. Then α,α′‐azobis‐(isobutyronitrile)‐initiated homopolymerization of the resultant gemcitabine monomers was performed and three polymer–gemcitabine conjugates with high gemcitabine content (>55 wt %) were synthesized. Moreover, radical copolymerization of the gemcitabine monomer 5′‐O‐vinyladipyl‐gemcitabine with different saccharide comonomers was performed, and three saccharide‐functionalized polymer–gemcitabine conjugates with 5.7–15.3 wt % gemcitabine content were obtained, among which the conjugates with galactose or lactose as pendants had potential hepatoma‐targeting function. All the resultant polymer–gemcitabine conjugates were characterized by IR, NMR, and gel permeation chromatography. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
17.
The aim of the this study is to develop colon targeted drug delivery systems for Ibuprofen using grafted katira gum as a carrier. Polyacrylamide‐grafted katira gum was synthesized by grafting acrylamide onto katira gum in presence of varying concentration of ceric ammonium nitrate (CAN) as initiator. Elemental analysis, FTIR, TGA, DTA, DSC, and SEM were used to characterize the grafting of acrylamide onto katira gum. Matrix tablets containing various proportions of grafted katira gum were prepared by wet granulation method. All the formulations were evaluated for hardness, drug content, swelling index, and in vitro release studies in simulated gastric fluid, small intestinal fluid, and simulated colonic fluid with and without enzymes. Ibuprofen was used for controlled release study. The drug release mechanism was studied by fitting into Peppas model and was found to be supercase‐II transport. Matrix tablets containing 0.3 g of CAN/gm of acrylamide showed optimum value and retained its physical integrity in simulated gastric, small intestinal and colonic fluid, where as other composition disintegrated within 2 h of dissolution testing in pH 1.2 buffer, simulated gastric fluid. The results of this study indicates that Ibuprofen matrix tablet containing 60 wt % composition of the above grafted katira gum would be potential formulations in delivering the drug to the colon and the more susceptible for enzymatic degradation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
18.
《Journal of Adhesion Science and Technology》2013,27(18-19):2251-2267
Abstract In recent years mucoadhesive drug delivery systems have been developed for oral, buccal, nasal, ocular, rectal and vaginal routes for either systemic or local effects. Mucoadhesive drug delivery systems are presently being explored because of their potential advantages including increased residence time of the drug at the site of application, relatively rapid uptake of the drug into the systemic circulation, and enhanced bioavailability of the therapeutic agents. This review focuses on trends and techniques for mucoadhesion assessment which includes various experimental methods that have been used for the characterization of mucoadhesive polymers and/or delivery systems. These techniques are categorized into two methods, namely methods for mechanism assessment and methods for formulation evaluation. The techniques used to evaluate mecha nisms of mucoadhesion include atomic force microscopy, texture analysis, rheological, wetting and zeta potential measurements for the assessment of interactions between the mucoadhesive polymer/system and mucosal surface. The methods for the evaluation of mucoadhesion based formulations are also further classified as ex vivo, in vitro as well as pharmacokinetic methods. Hence, the techniques highlight the possibility of evaluating mucoadhesion phenomenon in spite of its complexity. 相似文献
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Poly(N‐isopropylacrylamide)/alginate interpenetrating polymer network hydrogel beads (IPN beads) were prepared via modified inverse emulsion polymerization, and the effect of the synthesis temperature on the characteristics of the IPN beads was investigated. Varying the synthesis temperature from 10 to 40°C led to slight differences in the FTIR and elemental analysis results, whereas significant differences in optical color, thermoresponsive behavior, and release properties of vitamin B12 were observed. The IPN beads prepared at low temperature were transparent and exhibited a large and drastic thermoresponsive volume change. On the other hand, the IPN beads prepared at high temperature were opaque and exhibited a small and gradual thermoresponsive volume change. In addition, the diffusion coefficient in the IPN beads prepared at 10°C decreased with increasing solution temperature, whereas the diffusion coefficient in IPN beads prepared at 40°C increased with increasing solution temperature. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41814. 相似文献
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Therapeutic agents or agricultural fertilizers captured in polymer colloids (PCs) give rise to interesting applications, which are typically related to sustained release. We synthesized crosslinked polymer structures with poly(vinyl alcohol) (PVA) and borax precursors. Fourier transform infrared spectroscopy showed that a polymer–boron ion complex was formed with the crosslinking reaction at the O H site of PVA; thereby, PCs were formed. Field‐emission scanning electron microscopy showed that a uniform mesoporous two‐dimensional structure formed via intermolecular and intramolecular crosslinking. Trypsin enzyme and phosphate fertilizer were trapped in these PCs independently to study sustained release. Fertilizer‐incorporated PCs were mixed with soil samples, in which seeds of fenugreek were sown, and the plant growth was monitored a duration of 15 days. The fertilizer release, studied with UV–visible spectroscopy, showed a sustained signature of the fertilizer (at 690 nm) in the water extracts of soil, with much healthier plant growth compared to the control. For the trypsin‐incorporated PC samples, the released enzyme was made to interact with bovine serum albumin protein to monitor the released percentage with UV absorption spectroscopy. A systematic increase in the enzyme signature (at 280 nm) was observed for a duration of 60 min; this indicated the potential of PC for sustained drug release. The swelling calculations predicted that the mechanism involved was composed of pseudo‐swelling behavior. We envisaged that the hydroxyl groups of the PC broke in water and formed a complex with water. This complex slowly dissolved in water to release the entrapped molecules. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献