Ethylene Glycol Dimethacrylate Contents Research Articles

Development of Antioxidant and Antimicrobial Membranes Based on Functionalized and Crosslinked Chitosan for Tissue Regeneration.

Tissue engineering is an interdisciplinary field that develops new methods to enhance the regeneration of damaged tissues, including those of wounds. Polymer systems containing bioactive molecules can play an important role in accelerating tissue regeneration, mitigating inflammation process, and fighting bacterial infection. Chitosan (CS) has attracted much attention regarding its use in wound healing system fabrication thanks to its biocompatibility, biodegradability, and the presence of functional groups in its structure. In this work, bioactive chitosan-based membranes were obtained by both chemical and physical modifications of the polymer with glycidyl methacrylate and glycerol (GLY), respectively. The most suitable GLY concentration to obtain wound healing systems with good elongation at break, a good water vapor transmission rate (WVTR), and good wettability values was 20% (w/w). Afterwards, the membranes were crosslinked with different concentrations of ethylene glycol dimethacrylate (EGDMA). By using a concentration of 0.05 mM EGDMA, membranes with a contact angle and WVTR values suitable for the application were obtained. To make the system bioactive, 3,4-dihydrocinnamic acid (HCAF) was introduced into the membranes, either by imbibition or chemical reaction, using laccase as a catalyst. Thermal and mechanical analyses confirmed the formation of a cohesive network, which limited the plasticizing effect of GLY, particularly when HCAF was chemically bound. The HCAF-imbibed membrane showed a good antioxidant and antimicrobial activity, highlighting the potential of this system for the treatment of wound healing.

INVESTIGATION OF PHYSICOCHEMICAL AND THERMAL PROPERTIES OF CLAY-HYDROGEL COMPOSITES

Hydrogels are cross-linked polymeric networks which retain large amounts of water. The hydrogels with response capability to various stimuli such as pH and temperature have received great attention in many fields. In this study, hydrogels were synthesized by free radical solution polymerization through optimization of acrylamide/sodium acrylate mole ratio and ethylene glycol dimethacrylate content. With the addition of sepiolite as filler into the hydrogel network which had highest swelling percent, hydrogel composites were obtained. In the presence of 10 wt% sepiolite, maximum swelling percent was determined as approximately 10600%. Swelling properties of the hydrogel composite including 10 wt% sepiolite was investigated depending on pH, salt effect and temperature. With increasing pH value, swelling percent of the hydrogel composite showed an increase. At high temperatures, the hydrogel composite exhibited higher swelling percent. Swelling tests in 0.1 M NaCl, CaCl2 and FeCl3 solutions revealed that the lowest swelling percent was observed in 0.1 M FeCl3 solution. Fourier transform infrared spectroscopy (FTIR) analyses verified successfully preparation of the hydrogel composites. Regular layers of the sepiolite in the hydrogel network which made water diffusion easily were shown by scanning electron microscopy (SEM) analyses. Thermogravimetric analyses (TGA) indicated that thermal stability of the hydrogel network was increased with the addition of sepiolite.

Preparation and characterization of high solid content acrylate latex pressure sensitive adhesives with difunctional cross-linker EGDMA

Cross-linked acrylate latex pressure sensitive adhesives (PSAs) were synthesized via unseeded semi-batch emulsion polymerization processes with butyl acrylate (BA), acrylic acid (AA), 2-hydroxyethyl acrylate (HEA) and difunctional cross-linker, ethylene glycol dimethacrylate (EGDMA). The influences of EGDMA on the comprehensive properties of the acrylate latex PSAs were investigated. The results indicated that both viscosity and particle size of the latexes were independent of the amount of EGDMA in the pre-emulsion feed when unseeded semi-batch emulsion polymerization process was employed. It was also found that water resistance of the latex PSA was improved with increasing EGDMA content, further confirmed by water contact angle measurements. DSC and TGA results showed that Tg of the copolymer was elevated, plus thermal stability was increased with introduction of EGDMA. Besides, with the increase of EGDMA content, the gel content of the polymer increased. Moreover, for the cross-linked adhesive film, the shear strength was improved greatly while at the sacrifice of loop tack and peel strength, when compared with the uncross-linked counterparts.

Designing and In Vitro Characterization of pH-Sensitive Aspartic Acid-Graft-Poly(Acrylic Acid) Hydrogels as Controlled Drug Carriers.

Acetaminophen is an odorless and white crystalline powder drug, used in the management of fever, pain, and headache. The half-life of acetaminophen is very short; thus, multiple intakes of acetaminophen are needed in a day to maintain a constant pharmacological action for an extended period of time. Certain severe adverse effects are produced due to the frequent intake of acetaminophen, especially hepatotoxicity and skin rashes. Therefore, a drug carrier system is needed which not only prolongs the release of acetaminophen, but also enhances the patient compliance. Therefore, the authors prepared novel aspartic acid-graft-poly(acrylic acid) hydrogels for the controlled release of acetaminophen. The novelty of the prepared hydrogels is based on the incorporation of pH-sensitive monomer acrylic acid with polymer aspartic acid in the presence of ethylene glycol dimethacrylate. Due to the pH-sensitive nature, the release of acetaminophen was prolonged for an extended period of time by the developed hydrogels. Hence, a series of studies was carried out for the formulated hydrogels including sol-gel fraction, FTIR, dynamic swelling, polymer volume analysis, thermal analysis, percent porosity, SEM, in vitro drug release studies, and PXRD analysis. FTIR analysis confirmed the grafting of acrylic acid onto the backbone of aspartic acid and revealed the development of hydrogels. The thermal studies revealed the high thermal stability of the fabricated hydrogels as compared to pure aspartic acid. An irregular surface with a few pores was indicated by SEM. PXRD revealed the amorphous state of the developed hydrogels and confirmed the reduction in the crystallinity of the unreacted aspartic acid by the formulated hydrogels. An increase in gel fraction was observed with the increasing concentration of aspartic acid, acrylic acid, and ethylene glycol dimethacrylate due to the availability of a high amount of free radicals. The porosity study was influenced by the various compositions of developed hydrogels. Porosity was increased due to the enhancement in the concentrations of aspartic acid and acrylic acid, whereas it decreased with the increase in ethylene glycol dimethacrylate concentration. Similarly, the pH-responsive properties of hydrogels were evaluated by dynamic swelling and in vitro drug release studies at two different pH levels (1.2 and 7.4), and a greater dynamic swelling and acetaminophen release were exhibited at pH 7.4 as compared to pH 1.2. An increase in swelling, drug loading, and drug release was seen with the increased incorporation of aspartic acid and acrylic acid, whereas a decrease was detected with the increase in the concentration of ethylene glycol dimethacrylate. Conclusively, the formulated aspartic acid-based hydrogels could be employed as a suitable nonactive pharmaceutical ingredient for the controlled delivery of acetaminophen.

Formulation, Characterization, and In Vitro Drug Release Study of β-Cyclodextrin-Based Smart Hydrogels.

In this study, novel pH-responsive polymeric β-cyclodextrin-graft-poly(acrylic acid/itaconic acid) hydrogels were fabricated by the free radical polymerization technique. Various concentrations of β-cyclodextrin, acrylic acid, and itaconic acid were crosslinked by ethylene glycol dimethacrylate in the presence of ammonium persulfate. The crosslinked hydrogels were used for the controlled delivery of theophylline. Loading of theophylline was conducted by the absorption and diffusion method. The fabricated network of hydrogel was evaluated by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffractometry (XRD), and scanning electron microscopy (SEM). The crosslinking among hydrogel contents and drug loading by the fabricated hydrogel were confirmed by FTIR analysis, while TGA indicated a high thermal stability of the prepared hydrogel as compared to pure β-cyclodextrin and itaconic acid. The high thermal stability of the developed hydrogel indicated an increase in the thermal stability of β-cyclodextrin and itaconic acid after crosslinking. Similarly, a decrease in crystallinity of β-cyclodextrin and itaconic acid was observed after crosslinking, as evaluated by XRD analysis. SEM revealed an irregular and hard surface of the prepared hydrogel, which may be correlated with strong crosslinking among hydrogel contents. Crosslinked insoluble and uncrosslinked soluble fractions of hydrogel were evaluated by sol–gel analysis. An increase in gel fraction was seen with the increase in compositions of hydrogel contents, while a decrease in sol fraction was observed. Dynamic swelling and dissolution studies were performed in three various buffer solutions of pH 1.2, 4.6, and 7.4, respectively. Maximum swelling and drug release were observed at higher pH values as compared to the lower pH value due to the deprotonation and protonation of functional groups of the hydrogel contents; thus, the pH-sensitive nature of the fabricated hydrogel was demonstrated. Likewise, water penetration capability and polymer volume were evaluated by porosity and polymer volume studies. Increased incorporation of β-cyclodextrin, acrylic acid, and itaconic acid led to an increase in swelling, drug release, drug loading, and porosity of the fabricated hydrogel, whereas a decrease was detected with the increasing concentration of ethylene glycol dimethacrylate. Conclusively, the prepared hydrogel could be employed as a suitable and promising carrier for the controlled release of theophylline.

Development of Dental Poly(methyl methacrylate)-Based Resin for Stereolithography Additive Manufacturing.

Poly(methyl methacrylate) (PMMA) is widely used in dental applications. However, PMMA specialized for stereolithography (SLA) additive manufacturing (3D-printing) has not been developed yet. This study aims to develop a novel PMMA-based resin for SLA 3D-printing by mixing methyl methacrylate (MMA), ethylene glycol dimethacrylate (EGDMA), and PMMA powder in various mixing ratios. The printability and the viscosity of the PMMA-based resins were examined to determine their suitability for 3D-printing. The mechanical properties (flexural strength and Vickers hardness), shear bond strength, degree of conversion, physicochemical properties (water sorption and solubility), and cytotoxicity for L929 cells of the resulting resins were compared with those of three commercial resins: one self-cured resin and two 3D-print resins. EGDMA and PMMA were found to be essential components for SLA 3D-printing. The viscosity increased with PMMA content, while the mechanical properties improved as EGDMA content increased. The shear bond strength tended to decrease as EGDMA increased. Based on these characteristics, the optimal composition was determined to be 30% PMMA, 56% EGDMA, 14% MMA with flexural strength (84.6 ± 7.1 MPa), Vickers hardness (21.6 ± 1.9), and shear bond strength (10.5 ± 1.8 MPa) which were comparable to or higher than those of commercial resins. The resin’s degree of conversion (71.5 ± 0.7%), water sorption (19.7 ± 0.6 μg/mm3), solubility (below detection limit), and cell viability (80.7 ± 6.2% at day 10) were all acceptable for use in an oral environment. The printable PMMA-based resin is a potential candidate material for dental applications.

Separation and recognition characteristics by MIP manufacture using supercritical CO2 technology

This research is focused on the experiment of molecular imprinting polymers by supercritical solvent technology as friendly-environmental process. Methyl methacrylate (MMA) monomer, methacrylic acid (MAA) monomer, VA (vanillic acid) with template and EGDMA (ethylene glycol dimethacrylate) with cross-linking agent were used for molecular imprinting polymers composition. The template has been eliminated by the Soxhlet extraction method, and the rate of elimination is ca. 95–98 %. The adsorption capacities of the synthesized molecular imprinting polymers were estimated using the kinetics and isotherms of restraint, Scatchard investigation, affinity distributions, the materials adsorption with template-like structure, α (selectivity parameter), and HPLC (high performance liquid chromatography) analysis. The evaluation result shows that the manufactured molecular imprinting polymers have highly selectivity and separation ability. It was also confirmed that there was a difference between the adsorption amounts with EGDMA contents. In this study, prepared molecular imprinting polymers had an advantage in adsorption selectivity where VA and its structural analog materials are present. These results show that the molecular imprinting polymers selectivity was increased using control the cross-linking agent.

RETRACTED ARTICLE: Understanding mechanical characteristics of pH-responsive PEG 4000-based polymeric network for colorectal carcinoma: its acute oral toxicity study

The major objective of this study is to fabricate a very promising system by loading anticancer agent in it which could be given to the cancer patients by oral administration and additionally that will liberate drugs in large intestine (affected/cancerous area). Minimum or no exposure of chemotherapeutic agents to gastric/small intestine will significantly eliminate the problem of adverse drug reactions. Cancer patients are facing severe problem of side/adverse effects due to intravenous colorectal carcinoma chemotherapy. So, an oral drug delivery system is designed to substitute the intravenous drug therapy. This study reports the synthesis of hybrid polymeric polyethylene glycol hydrogels (PEGA 4000) based on acrylic acid (AA), ammonium peroxodisulfate and ethylene glycol dimethacrylate (EGDMA) by solution polymerization method. PEGA 4000 hydrogels were used for colon targeting of hydrophilic anti-carcinoma drug (oxaliplatin). Development of new structure was confirmed by Fourier transform infrared spectroscopy. Surface morphology of developed hydrogel slabs was examined by scanning electron microscopy. Thermal gravimetric analysis of hydrogels revealed that there was an increase in thermal stability of PEGA 4000 hydrogels. Swelling study was performed in acidic and basic pH medium provided important information on drug release characteristics of hydrogels. The release of oxaliplatin (OXP) was significantly retarded at pH 1.2, while rapid release was observed at pH 7.4. The release rate of OXP increased with increasing concentration of PEG 4000 and AA. However, extent of drug release was significantly reduced on increasing concentration of EGDMA. Mechanism of release has been evaluated by applying various mathematical kinetic models. The tensile mechanical strength and elongation at break were also observed on different formulations based on various ratios of reaction contents. The consequents of our study suggest that fabricated PEGA 4000 hydrogels could serve as suitable target release delivery system and toxicity study endorsed biocompatibility of hydrogels to biological system.

Thermally expandable nanocapsules obtained from surfactant-free emulsion polymerization

In this work, thermally expandable nanocapsules (TENs) with a core/shell structure were prepared by one-step surfactant-free emulsion polymerization (SFEP). Acrylonitrile (AN), butyl acrylate (BA), and methyl methacrylate (MMA) were used as the main monomers while ethylene glycol dimethacrylate (EGDMA) was employed as the crosslinking agent. In addition, toluene-p-sulfonyl hydrazide (TSH) was chosen as the blowing agent. Via SFEP, TENs were obtained without the negative effects exerted from emulsifiers and suspension stabilizers. The diameter of these synthesized nanocapsules was about 260 nm, and their core/shell structure was demonstrated by transmission electron microscopy (TEM). The thermal stability of the nanocapsules was studied by thermogravimetric analysis (TGA). In addition, the morphology of nanocapsules before and after expansion was investigated by means of scanning electronic microscopy (SEM) analysis. The thermo-expandable properties, including the start expansion temperature and the maximum expansion temperature, were tested by dilatometer (DIL). The results show that all of the samples exhibited expansion behavior while both the EGDMA concentration and shell composition had an influence on the thermo-expandable properties of the synthesized nanocapsules.

Macroporous Oil-Sorbents with a High Absorption Capacity and High-Temperature Tolerance Prepared through Cryo-Polymerization.

The facile preparation and admirable performance of macro-porous poly(lauryl acrylate)-based oil-sorbents for organic solvents and oils are reported in this manuscript. Cryo-polymerizations of lauryl acrylate (LA) with ethylene glycol dimethacrylate (EGDMA) as the cross-linker were carried out at temperatures below the freezing point of the polymerization mixture. The polymerization medium and pore-forming agent was 1,4-dioxane. The influences of the total monomer concentration, EGDMA content and cryo-polymerization temperature on the structure of the obtained P(LA-co-EGDMA) cryogels were investigated with the techniques of Fourier transform infrared spectroscopy, scanning electron microscopy, contact angle measurement and thermo-gravimetric analysis. Through the modulation of the crosslinking density and porosity of these cryogels, the P(LA-co-EGDMA) oil-sorbents demonstrated a high absorption capacity for organic solvents and oils, recyclability and high-temperature tolerance. The absorption capacity reached 20–21 and 16–17 g/g for toluene and gasoline oil, respectively. Those fabricated sorbents survived high temperatures up to 150 °C without any change in absorption capacity as well as porosity. Considering the convenient synthesis process and absorption performance, the present work offers a remarkable opportunity to bring polymer cryogels to practical application in waste oil clean-up.

Porous, bicontinuous, and cationic polyelectrolyte obtained by high internal phase emulsion polymerization

In this work, a cationic polyelectrolyte was synthesized through oil‐in‐water high internal phase emulsion polymerization. The porous polymer was obtained using the monomer (4‐vinyl benzyl)trimethylammonium chloride and cross‐linked with N,N‐methylene‐bis‐acrylamide; additionally, ethylene glycol dimethacrylate (EGDMA) was used as the second cross‐linker, which was solubilized in the discontinuous phase leading to a bicontinuous‐like HIPE system because of the characteristics of this cross‐linker and the phase, where polymerized several effects on the polyHIPE were expected. In this way, the effect of the emulsifier and EGDMA content on the pore size, swelling, and rheological properties was assessed. It was observed that an increased concentration of the emulsifier in the polymerization decreased the pore size, narrowed its size distribution, and diminished the swelling capacity of the polymer. Additionally, the poly (HIPE) displayed a close‐cell structure explained by the locus of initiation starting from the droplets of the emulsion. After the addition of EGDMA, the polymer exhibited a major decrease in pore size and a significant decrease in swelling attributed to the polymerized skin layer on the droplet and hydrophobicity provided by the polyEGDMA, respectively. Rheological assays revealed an increase in the complex modulus and shear stress as the pore size decreased, but the addition of EGDMA did not produce an increase in the modulus, as expected. Finally, the sorption capabilities of the cationic porous polymers were evaluated through kinetic and isotherm sorption experiments using the anionic dye Acid Black 24.

Enhancing mechanical properties of an injectable two-solution acrylic bone cement using a difunctional crosslinker.

Two-solution bone cements modified with ethylene glycol-dimethacrylate (EG-DMA) as a crosslinker have been developed as an attempt to further improve the mechanical properties of acrylic bone cement. The result of this study shows that EG-DMA can increase the mechanical properties and fractional monomer conversion while preserving the thermal characteristics. The strength and bending modulus increase with EG-DMA concentrations at 5-10 vol % EG-DMA. Substituting the EG-DMA content past 10 vol % decreases the bending properties due to the effects of reduced monomer concentrations. Strengthened EG-DMA samples demonstrated an increase in ductility with noticeably different fracture surface morphologies than the control samples, indicated by microtroughs and ridge formation caused by excessive plastic strain. This work provides insight into the effect of substituting a crosslinker for MMA monomer in an injectable two-solution system and lays out the ideal concentrations of EG-DMA for superior mechanical or fractional monomer conversion properties. © 2018 Wiley Periodicals, Inc. J. Biomed. Mater. Res. Part B, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 783-790, 2019.

Effect of crosslinking concentration on properties of 3-(trimethoxysilyl) propyl methacrylate/N-vinyl pyrrolidone gels

BackgroundThe incorporation of two different monomers, having different properties, in the same polymer molecule leads to the formation of new materials with great scientific and commercial importance. The basic requirements for polymeric materials in some areas of biomedical applications are that they are hydrophilic, having good mechanical and thermal properties, soft, and oxygen-permeable.ResultsA series of 3-(trimethoxysilyl) propyl methacrylate/N-vinyl pyrrolidone (TMSPM/NVP) xerogels containing different concentration of ethylene glycol dimethacrylate (EGDMA) as crosslinking agent were prepared by bulk polymerization to high conversion using BPO as initiator. The copolymers were characterized by FTIR. The corresponding hydrogels were obtained by swelling the xerogels in deionized water to equilibrium. Addition of EGDMA increases the transparency of xerogels and hydrogels. The minimum amount of EGDMA required to produce a transparent xerogel is 1%. All the Swelling parameters, including water content (EWC), volume fraction of polymer (ϕ2) and weight loss during swelling decrease with increasing EGDMA. Young’s and shear modulus (E and G) increase as EGDMA increases. The hydrogels were characterized in terms of modulus cross-linking density (ve and vt) and polymer-solvent interaction parameters (χ). Thermal properties include TGA and glass transition temperature (Tg) enhance by adding EGDMA whereas the oxygen permeability (P) of hydrogels decreases as water content decrease.ConclusionsThis study prepared and studied the properties for new copolymer (TMSPM-co-NVP) contains different amounts of (EGDMA). These copolymers possess new properties with potential use in different biomedical applications. The properties of the prepared hydrogels are fit with the standard properties of materials which should be used for contact lenses.

Cytotoxicity and DNA double-strand breaks in human gingival fibroblasts exposed to eluates of dental composites

ObjectivePreviously, single composite components were used to study cytotoxicity and induction of DNA double-strand breaks (DNA-DSBs) of dental composite resins. In the present study, cytotoxicity and induction of DNA-DSBs in human gingival fibroblasts (HGFs) were investigated with dental composite eluates consisting of multiple components. The eluates were qualified and quantified. MethodsThe composites Esthet.X® HD, Venus®, X-tra fil®, CLEARFIL™ AP-X, Admira® Fusion and QuiXfil® were polymerized and immersed into Dulbecco’s modified Eagle’s medium (DMEM) for 72h. Subsequently, HGFs were incubated with the corresponding composite eluates. The cell viability of HGFs was obtained from an XTT assay. DNA-DSBs were determined using a γ-H2AX assay. The qualification and quantification of eluates were performed by gas chromatography/mass spectrometry (GC/MS). ResultsHGFs exposed to the eluates of all investigated composites showed no significant loss of cell viability, compared to negative control. Significant DNA-DSBs induction could be found in HGFs exposed to the eluates of Esthet.X® HD (0.43±0.05 foci/cell) and Venus® (0.39±0.04 foci/cell), compared to control (0.22±0.03 foci/cell). A total of 12 substances were detected from the investigated composite eluates. Five of them were methacrylates: tetraethyleneglycol dimethacrylate (TEGDMA), 2-hydroxyethyl methacrylate (HEMA), hydroxypropyl methacrylate (HPMA), ethyleneglycol dimethacrylate (EGDMA) and trimethylolpropane trimethacrylate (TMPTMA). The highest concentration of HEMA (110.5μM), HPMA (86.08μM) and TMPTMA (4.50μM) was detected in the eluates of QuiXfil®. The highest concentration of TEGDMA was 1080μM in Venus® eluates and the highest concentration of EGDMA was 3.18μM in Esthet.X® HD eluates. SignificanceSignificant DNA-DSBs induction can be found in HGFs exposed to the eluates of Esthet.X® HD and Venus®. The interactive effects among released (co)monomers and additives may influence the cytotoxicity and induction of DNA-DSBs, compared to exposure with single composite component.

Synthesis, characterization and toxicological evaluation of pH-sensitive polyelectrolyte Nanogels

Nanogels are polymeric nanoparticles that have similar characteristic to hydrogels, but have the size in nano range. The pH-sensitive nanogel have gained much interest in the field of pharmaceutical nanotechnology as they have potential to be used as nanocarriers in drug delivery system. The aim of the present study was to synthesize pH-sensitive polyelectrolyte MMA/IA nanogels using free radical polymerization containing methyl methacrylate (MMA), itaconic acid (IA), and a crosslinker ethylene glycol dimethacrylate (EGDMA). In the synthesis of nanogels four parameters i.e. ethanol/water ratios (v/v), dilution volume using ethanol/water (v/v), crosslinker EGDMA concentration, and monomers MMA/IA ratios were optimized. Their effect on particle size, PdI, zeta potential and swelling ratio were evaluated. The swelling behaviour of the nanogels was studied by measuring swelling ratio using gravimetric method. The optimized nanogels were characterized by proton nuclear magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FTIR), liquid chromatography/time-of-flight/mass spectrometry (LC-TOF-MS), X-ray powder diffraction (X-RD) and transmission electron microscopy (TEM). Polyelectrolyte characteristic was confirmed by measuring isoelectric point using aqueous electrophoresis. The in-vitro and in-vivo toxicity studies were performed by MTT assays using Caco-2 cells and Limit test using female Sprague Dawly rats, respectively. The nanogels were amorphous in nature, exhibited pH-responsive property and polyelectrolyte characteristics, which showed an isoelectric point at pH 2.78. They had an average particle size <250 nm, narrow size distribution (PdI < 0.3), and negative zeta potential. The in-vitro MTT assays indicated that the nanogels had no sign of cytotoxicity. The in vivo Limit test showed that the LD50 was greater than 2000 mg/kg body weight. The necrospy, histopathology and hematological studies also revealed no sign of toxicity. These findings suggested that the MMA/IA nanogels are pH-sensitive, non-toxic and have potential to form a polyelectrolyte complex with oppositely charged of macromolecular drugs.

Adsorption and separation properties of gallic acid imprinted polymers prepared using supercritical fluid technology

Molecularly imprinted technique is one of the methods to form specific memory sites in a polymer matrix with the template. For main objective of this work, we prepared molecularly imprinted polymers (MIPs) using supercritical fluid technique as an eco-friendly process. MIPs were synthesized using methyl methacrylate (MMA) as a third monomer, methacrylic acid (MAA) as a functional monomer, gallic acid (GA) as a template, and ethylene glycol dimethacrylate (EGDMA) as a crosslinking agent. The template was removed through the method of Soxhlet extraction, and the removal ratio was about 95–99%. The adsorption abilities of prepared MIPs was evaluated by binding kinetics, the binding isotherms, Scatchard analysis, the adsorption of materials with structures similar to templates, high performance liquid chromatography (HPLC) analysis, and the selectivity factor (a), The results of the evaluation indicate that the prepared MIPs have high separation abilities and selectivity. In addition, we identified that although there was a difference of adsorption quantities with the crosslinking agent contents (EGDMA contents), MIPs synthesized in this study had good adsorption selectivity in the presence of GA and its structure analogue materials. From this result, it could be found that the selectivity of MIPs was improved significantly by controlling the crosslinking agent.

Effect of ethylene glycol dimethacrylate on swelling and on metformin hydrochloride release behavior of chemically crosslinked pH-sensitive acrylic acid-polyvinyl alcohol hydrogel.

BackgroundThe present work objective was to prepare and to observe the effect of ethylene glycol dimethacrylate on swelling and on drug release behavior of pH-sensitive acrylic acid–polyvinyl alcohol hydrogel.MethodsIn the present work, pH sensitive acrylic acid–polyvinyl alcohol hydrogels have been prepared by free radical polymerization technique in the presence of benzoyl peroxide as an initiator. Different crosslinker contents were used to observe its effect on swelling and on drug release. Dynamic and equilibrium swelling studies of prepared hydrogels were investigated in USP phosphate buffer solutions of pH 1.2, 5.5, 6.5 and 7.5 with constant ionic strengths. Hydrogels were evaluated for polymer volume fraction, solvent interaction parameter, molecular weight between crosslinks, number of links per polymer chain, diffusion coefficient, sol–gel fraction and porosity. To demonstrate the release pattern of the drug, zero-order, first-order, higuchi and korsmeyer-peppas models were applied. Quality and consistency of hydrogels was examined by FTIR and surface morphology of hydrogels was examined by SEM.ResultsDecrease in swelling and in drug release was seen by increasing content of ethylene glycol dimethacrylate. A remarkable high swelling was observed at high pH indicating the potential of this hydrogel for delivery of drugs to intestine. By increasing the concentration of ethylene glycol dimethacrylate, porosity decreased. Order of release was observed first order in all cases and the mechanism was non–fickian diffusion. FTIR confirmed the formation of network. SEM results showed the incorporation of drug.ConclusionThe prepared hydrogels can be suitably used for targeted drug delivery to the intestine.

Preparation and characterization of molecularly imprinted poly(hydroxyethyl methacrylate) microspheres for sustained release of gatifloxacin

Molecularly imprinted poly(hydroxyethyl methacrylate) microspheres (PHEMA MIPMs) were prepared via precipitation polymerization in this article, using gatifloxacin (GFLX), hydroxyethyl methacrylate (HEMA), and ethylene glycol dimethacrylate (EGDMA) as template molecule, functional monomer and cross-linker, respectively. The effects of reaction medium, initial total monomers, cross-linker and molecular imprinting on the polymerization were investigated systematically. The interaction between GFLX and HEMA in pre-solution was studied by UV-Visible spectrophotometer, both size and morphology of products were characterized by a scanning electron microscope. When the total initial monomer concentration was 1 vol%, EGDMA content was 70 mol%, a group of uniform PHEMA MIPMs were prepared at different GFLX/MAA molar ratios, with diameter range from 2.06 ± 0.07 to 2.82 ± 0.20 μm. The results of drug loading and in vitro release experiments demonstrated that PHEMA MIPMs could achieve a higher GFLX loading content and a more acceptable sustained release than non-imprinted ones.

Synthesis and characterization of a porous poly(hydroxyethylmethacrylate‐co‐ethylene glycol dimethacrylate)‐based hydrogel device for the implantable delivery of insulin

AbstractPoly(hydroxyethylmethacrylate‐co‐ethylene glycol dimethacrylate) [poly(HEMA‐co‐EGDMA)]‐based hydrogel devices were synthesized by a free‐radical polymerization reaction with 2‐hydroxyethylmethacrylate as the monomer, different concentrations of ethylene glycol dimethacrylate (EGDMA) as the crosslinking agent, and ammonium persulfate/N,N,N′,N′‐tetra‐methyl ethylenediamine as the free‐radical initiator. The porosity of the poly(HEMA‐co‐EGDMA) hydrogels was controlled with water as the porogen. The Fourier transform infrared spectrum of poly(HEMA‐co‐EGDMA) showed absorption bands associated with CO stretching at 1714 cm−1, COC stretching vibrations at 1152 cm−1, and a broad band at 3500–3800 cm−1 corresponding to OH stretching. Atomic force microscopy studies showed that the hydrogel containing 67% water had pores in the range of 3500–9000 nm, whereas the hydrogel containing 7% water did not show measurable pores. The hydrogel synthesized with 1% EGDMA showed 50% thallium‐201 release within the first 30 min and about 80% release within 60 min. In vitro insulin‐release studies suggested that the hydrogel with 27% water showed sustained release up to 120 min, whereas the hydrogels with 47 and 67% water showed that nearly all of the insulin was released within 60 min. Hydrogel devices synthesized with 27% water and filled with insulin particles showed sustained release for up to 8 days, whereas the hydrogels synthesized with 47 and 67% water released insulin completely within 3 days of administration. Animal studies suggested that the hydrogel devices synthesized with 27% water and filled with insulin‐loaded particles (120 IU) were able to control blood glucose levels for up to 5 days after implantation. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Uniform molecularly imprinted poly(methacrylic acid) nanospheres prepared by precipitation polymerization: the control of particle features suitable for sustained release of gatifloxacin

Herein we have combined the molecular imprinting technique and thermally-initiated precipitation polymerization to develop novel molecularly imprinted poly(methacrylic acid) nanospheres (PMAA MIPNs) for sustained release of gatifloxacin (GFLX). In the process, ethylene glycol dimethacrylate (EGDMA) and GFLX were used as the cross-linker and template, respectively. The effects of reaction medium and concentration of the monomers such as MAA, EGDMA and GFLX were systematically investigated. Uniform nanospheres with diameter equal to 136.0 ± 8.1 nm and particle dispersion index (PDI) equal to 1.01 were obtained when the total monomer concentration was 1 vol%, the EGDMA content was 70 mol% and the GFLX/MAA ratio was 1 : 15 (mol/mol). The drug loading profiles and in vitro release studies indicated that PMAA MIPNs are better drug delivery vessels and have an improved release profile than non-imprinted ones, which was attributed to the reinforced interaction between GFLX and PMMA side groups due to the specific GFLX molecular arrangement in the PMAA polymeric matrix. Based on these results, these novel PMAA MIPNs are a promising candidate for sustained release of GFLX.