Swelling Properties of New Hydrogels Based on the Dimethyl Amino Ethyl Acrylate Methyl Chloride Quaternary Salt with Acrylic Acid and 2-Methylene Butane-1,4-Dioic Acid Monomers in Aqueous Solutions (original) (raw)
Related papers
Hemijska industrija, 2012
The aim of this paper is to propose equations for the diffusion of drugs for investigated drug/hydrogel systems using the parameters affecting the transport of drug through poly-(2-hydroxyethylmethacrylate/itaconic acid) (P(HEMA/IA)), poly(2-hydroxyethylacrylate/itaconic acid) (P(HEA/IA)), and poly(2-hydroxyethylmethacrylate/poly(alkyleneglycol) (meth)acrylates) (P(HEMA/BIS)) copolymeric hydrogels. Different monomer types, as well as the variable content of some components in hydrogel composition (the amount of ionizable comonomer (IA) and different type of nonionic poly(alkyleneglycol) (meth)acrylates), ultimately defined the pore size available for drug diffusion. The hydrogels synthesized ranged from nonporous to microporous, based on the classification in accordance to the pore size, and could be classified as hydrogels that contain ionic groups and hydrogels without ionic groups. The drugs selected for this study are bronchodilators-theophylline (TPH), fenethylline hydrochloride (FE), and antibiotic cephalexin (CEX). Results of in vitro drug release tests defined the release systems based on the drug type, as well as the type of hydrogel used. The diffusion coefficient of drugs and the restriction coefficient, λ, defined as the ratio of solute to "pore" radius (r s /r ζ ) that describes the ease of drug release from the gels, were used as factors that govern the release process.
Polymer, 1982
The diffusion of solutes in gels is comprehensively reviewed. Because it has been a source of confusion, precise definitions of the gel diffusion coefficient are presented and discussed. Theories as to the effect of the gel substance on the course of diffusion are critically evaluated. These include the obstruction effect, hydrodynamic drag and other frictional couplings, alteration of solvent properties and (for homogeneous gels) the free volume theory. A large proportion of the data on diffusion in gels to be found in the literature is displayed, with the exception of those systems where binding of the solute is a major factor. The success of the theories in accounting for these results is examined. It is concluded that for heterogeneous gels the obstruction effect is prevalent, for organic solvent-polymer systems the free volume theory has had some success while diffusion of both macromolecules and micromolecular solutes in homogeneous gels is not well understood and deserves more experimental effort.
European Polymer Journal, 2002
Diffusion of aqueous sodium dodecyl sulfate (SDS) across cross-linked polyacrylamide hydrogel membranes has been studied by electrical conductivity measurements. Initial rapid sorption of SDS (as unimer) into the membranes is observed. The effect of SDS concentration, and of cross-linker fraction on the degree of swelling of the gels is studied and associated with binding of the surfactant to the polymer, with surface bound water suggested to be involved in these interactions. Below the surfactant critical micelle concentration, volume collapse of less cross-linked membranes is observed, and associated with aggregate formation. Fluorescence measurements using pyrene as a probe show that micellar aggregates do not diffuse through the membrane, and only overall unimer diffusion is observed. The effect of cross-linking on the diffusion process is discussed.
Chemical Industry
Hydrogels are synthesized by the method of radical polymerization of monomers: N-isopropylacrylamide (NIPAM) and acrylic acid (AA). Characterization of poly(N-isopropylacrylamide- co-acrylic acid) hydrogels, p(NIPAM/AA), has been performed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and by determination of the swelling behaviour in aqueous solutions at different temperatures (25, 31 and 37?C) and pH values (2.2, 4.5, 6 and 6.8). After lyophilisation in the solution at pH 6 and temperature of 25?C, p(NIPAM/AA) hydrogels have rapidly reached equilibrium degree of swelling, ?e, in comparison to non-lyophilized samples. The mechanism of solvent transport within matrix in lyophilized samples corresponds to less Fickian diffusion, whereas Super case II diffusion is characteristic for non-lyophilized samples. p(NIPAM/AA) hydrogel with 1.5 mol% of ethylene glycol dimethacrylate (EGDM) at the temperature of 25?C and pH 6.8, has reached the highest swelling equi...
Transport of a model diffusion probe in polyelectrolyte-surfactant hydrogels
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2019
Interactions of biopolymeric electrolytes with oppositely charged surfactants can result in micelle-like nanocontainers capable to dissolve hydrophobic substances. These micelle-like nanostructures can solve problems with hydrophobic nature of pharmaceutically active substances and be potentially usable for medical applications. In this study, two types of hydrogels were prepared: 1) based on hyaluronan and cationic surfactant septonex (carbethoxypendecinium bromide) and 2) based on diethylaminoethyl dextran and sodium dodecylsulphate. Nile red as a dye diffusion probe was incorporated into hydrogel in their preparation and then its release into surfactant solution and physiological saline was monitored. The release of NR from hydrogels was characterized by the effective diffusion coefficients of NR and structural parameters of hydrogels. The diffusion of NR in hydrogels was dependent on the molecular weight of polyelectrolyte and the ratio between charges of polyelectrolyte and surfactant. In the case of lower ratios, a bigger part of NR was probably incorporated in "pearl necklace structure" which suppressed its mobility. The increase of concentration of surfactant was connected with higher content of NR in free micelles or micelle-like aggregates and the increase in the release of NR. The formation of bigger micelles based on NR and SDS (in comparison with micelles based on NR and septonex surfactant) resulted in their lower diffusivity.
Journal of the Serbian Chemical Society, 2007
The isothermal kinetics curves of the swelling of a poly(acrylic acid) hydrogel in distilled water and physiological solution at temperatures ranging from 20 to 40 ºC were determined. The possibility of applying both the Fick's kinetics model and kinetics model of the first order chemical reaction to the swelling kinetics of the PAA hydrogel in distilled water and physiological solution were examined. It was found that the possibilities of applying these models were limited. The new model of the kinetics of swelling in distilled water and physiological solution was established. The kinetic parameters (E a , ln A) for the swelling in distilled water and physiological solution were determined. The decrease of the equilibrium degree of swelling and the saturation swelling rate of the swelling of the PAA hydrogel in physiological solution compared to swelling in distilled water could be explained by the decreased differences in the ionic osmotic pressures between the hydrogel and the swelling medium. The increase of the initial swelling rate in the physiological solution might be caused by an increased density of charges at the network and by an increased affinity of the network towards the water molecules. The increase of the activation energy of the swelling of the PAA hydrogel in the physiological solution is a consequence of its additional "ionic crosslinking".
A fluorescence study on swelling of hydrogels (PAAm) at various cross-linker contents
Advances in Polymer Technology, 2009
Disk-shaped acrylamide (AAm) gels were prepared from AAm with various N,N -methylenebisacrylamide (Bis) contents as cross-linker in the presence of ammonium persulfate as an initiator by free-radical cross-linking copolymerization in water. Polyacrylamide (PAAm) gels were dried before using for swelling experiments. Steady-state fluorescence spectrometer was employed during the swelling of PAAm hydrogels in water. Pyranine was introduced as a fluorescence probe. Fluorescence intensity of pyranine from various Bis content gel samples was measured during in situ swelling process. It was observed that fluorescence intensity decreased as swelling has proceeded. Gravimetric and volumetric experiments were also performed. The Li-Tanaka equation was used to determine the swelling time constants, τ c , and cooperative diffusion coefficients, D c , from intensity, weight, and volume variations during the swelling processes. It was observed that swelling time constants, τ c , increased and diffusion coefficients, D c , decreased as the cross-linker content was increased. C
Swelling of Acrylamide-Tartaric Acid Hydrogels
2005
Acrylamideltartarlc acid hydrogels in the form of rods are prepared by irradiating aqueous solutions of 1 g of acrylamide and varying quantities of tartaric acid between 0-60 mg in 1 mL of water, with 2.605.71 Id3y Y-rays. The influence of dose and relative content of tartaric acid on the swelling properties, diffusional behavior of water, diffusion coefficients and network properties (i.e ., number-average molar mass between crosslinks, crosslink density, number of elastically effective chains, number of repeating units between crosslinks and mesh size) of hydrogel systems is examined. Hydrogels are swelled in the range 700-1400%, while polyacrylamide hydrogels are swelled In the range 650-700%. Water diffusion to hydrogels is non-Fickian type diffusion .
Studying On The Small Molecule Diffusion Into Hydrogels: A Fluorescence Study
2007
Disc shaped acrylamide gels were prepared from Acrylamide (AAm) with various N, N' methlenebis (acrylamide) (Bis) as crosslinker in the presence of ammonium persulfate (APS) as an initiator by free-radical crosslinking copolymerization (FCC) in water. Steady state fluorescence (SSF) spectrometer was employed for studying drying and swelling of polyacrylamide (PAAm) hydrogels. Pyranine was introduced as a fluorescence probe. Fluorescence intensity of pyranine was measured during in situ drying and swelling processes at various temperatures. It is observed that fluorescence intensity of pyranine increased during drying process. An empirical equation was introduced to determine the desorption coefficients, D of water molecules from drying gels at various temperatures. The desorption activation energy ∆E d value was measured for the drying processes and found to be 91.08 kJmol -1 by fluorescence method. On the other hand, it is observed that τ values decreased and diffusion coefficients, D c increased as the swelling temperature is increased. Li-Tanaka equation was used to determine the swelling time constants, τ c and cooperative diffusion coefficients, D c from intensity during the swelling processes. The swelling activation energy, ∆E s value was measured from the intensity variation and found to be 10.7 kJmol -1 .
Influence of some aromatic amino acids on the swelling behavior of acrylamide/maleic acid hydrogel
Polymer Bulletin, 1998
Influence of some aromatic amino acids (histidine, phenylalanine and tryptophan) on the swelling behavior of acrylamide/maleic acid hydrogel (AAm/MA) prepared by γ-radiation was investigated. Swelling tests of AAm/MA hydrogel were made in buffer solutions and amino acid solutions at various pH at 37 ºC. The pH values are ionization of α-carboxyl groups (pK' 1 ), α-amino groups (pK' 2 ) and, isoelectric points (pI) of amino acids. The swelling of AAm/MA hydrogel increased when pH values of solutions were increased. The value of equilibrium swelling of AAm/MA hydrogel was 1035% at pH 10 buffer, while it was 880% at pH 2 buffer. The values of equilibrium swelling of AAm/MA hydrogel in phenylalanine, tryptophan and histidine solutions varied among 1130-1245% at pH 10, while they were among 790-975% at pH 2. The rate constant of swelling, diffusional exponent, network parameter and, diffusion and intrinsic diffusion coefficient were calculated by swelling kinetics. Diffusion of the penetrants into the hydrogel was found to be non-Fickian character. The diffusion coefficients of the hydrogel varied between 3.33x10 -6 -7.71x10 -6 cm 2 s -1 , while the intrinsic diffusion coefficients waried between 4.03x10 -6 -8.48x10 -6 cm 2 s -1 .