Swelling and diffusion studies of poly(N-isopropylacrylamide/itaconic acid) copolymeric hydrogels in water and aqueous solutions of drugs (original) (raw)
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Anticancer drug release from poly(N-isopropylacrylamide/itaconic acid) copolymeric hydrogels
Radiation Physics and Chemistry, 2005
The drug uptake and release of anticancer drug from N-isopropylacrylamide/itaconic acid copolymeric hydrogels containing 0-3 mol% of itaconic acid irradiated at 48 kGy have been investigated. 5-Fluorouracil (5-FU) is used as a model anticancer drug. The effect of 5-FU solution on swelling characteristics of PNIPAAm and P(NIPAAm/IA) copolymeric hydrogels have also been studied. The percent swelling, equilibrium swelling, equilibrium water/5-FU content and diffusion constant values are evaluated for poly(N-isopropylacrylamide) (PNIPAAm) and poly(Nisopropylacrylamide/itaconic) (P(NIPAAm/IA)) hydrogels at 130 ppm of 5-FU solution at room temperature. Diffusion of 5-FU solution into the hydrogels has been found to be the non-Fickian type. Finally, the kinetics of drug release from the hydrogels are examined. r
Release and Diffusion Studies of Hydrogels Based on Itaconic Acid
Materials Science Forum, 2007
Controlled release studies of drugs (theophylline (TH), fenethylline hydrochloride (FE) and gentamicin sulphate (GS)) from pH sensitive poly(2-hydroxyethyl methacrylate/itaconic acid) (P(HEMA/IA)) hydrogels obtained by gamma irradiation were carried out to investigate transport phenomena. Drug behavior and release profiles were analyzed using the restriction coefficient combining the influence of network structure and the size of the drug on release and transport properties. The results demonstrated that the ratio of drug radius to polymer pore size and drugpolymer interactions were dominant factors in hindering the diffusion process. The diffusivity of a drug through the hydrogels decreases with the size of the drug molecules and with the decrease in gel pore size. The diffusion equations for used drugs explain drug transport in hydrogels.
International Journal of Pharmaceutics, 2004
N-isopropylacrylamide/itaconic acid copolymeric hydrogels were prepared by irradiation of the ternary mixtures of Nisopropylacrylamide/itaconic acid/water by ␥-rays at ambient temperature. The effect of comonomer concentration, irradiation dose and pH on the swelling equilibria were studied. Lidocaine was used as a model drug for the investigation of drug release behaviour of hydrogels. Lidocaine adsorption capacity of the hydrogels were found to increase from 3.6 to 862.1 (mg lidocaine/g dry gel) with increasing amount of itaconic acid in the gel structure. Adsorption and release processes were followed at 4 and 37 • C, respectively. The release studies showed that the basic parameters affecting the drug release behaviour of the hydrogels were pH and temperature of the solution and cross-link density of the gels.
Polymers for Advanced Technologies, 2004
N-Isopropylacrylamide/itaconic acid copolymeric hydrogels were prepared by irradiation of the ternary mixtures of N-isopropylacrylamide/itaconic acid/water by c-rays at ambient temperature. The dependence of swelling properties and phase transitions on the comonomer concentration and temperature were investigated. The hydrogels showed both temperature and pH responses. The effect of comonomer concentration on the uptake and release behavior of the hydrogels was studied. Methylene blue (MB) was used as a model drug for the investigation of drug uptake and release behavior of the hydrogels. The release studies showed that the basic parameters affecting the drug release behavior of the hydrogels were pH and temperature of the solution.
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.
International Journal of Biosciences (IJB), 2014
The diffusion mechanism of a model anti-cancer drug in cross-linked poly(N-isopropylacrylamide/acrylic acid) (P(NIPAAm/AA) copolymeric hydrogels was studied. The crosslinking ratiowas constant but acrylic acid ratio ranged from 10:1 to 10:3. P(NIPAAm/AA) copolymeric hydrogels were synthesized by redox-initiated free radical polymerization in water at room temperature The presence of poly(ethyleneglycol) in the hydrogel formulation resulted the higher mechanical strength. Use of acrylic acid resulted in higher hydrogel swelling. Drug size was also found to be a significant factor. 5-FU is used as amodel anti-cancer drug. The effect of 5-FU solution on swelling characteristics P(NIPAAm/AA) copolymeric hydrogels have also been studied. The percent swelling, equilibrium swelling, diffusion constant values are evaluated for P(NIPAAm/AA) copolymeric hydrogels at 1.5% of 5-FU solution at room temperature Based on the release kinetic of the 5-FU drug, the hydrogels displayed a non-Fickian diffusion mechanism. According the diffusion kinetic data in hydrogels became clear that diffusion kinetic data were best described by Peppas model. Permeation from P(NIPAAm/AA) copolymeric hydrogels followed a Super Case II transport mechanism, most likely driven by macro molecular chain relaxation and swelling of hydrophilic polymers.
Radiation Physics and Chemistry, 2007
The copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were synthesized by gamma radiation induced radical polymerization. Swelling and thermodynamic properties of PHEMA and copolymeric P(HEMA/IA) hydrogels with different IA contents (2, 3.5 and 5 mol%) were studied in a wide pH and temperature range. Initial studies of so-prepared hydrogels show interesting pH and temperature sensitivity in swelling and drug release behavior. Special attention was devoted to temperature investigations around physiological temperature (37 1C), where small changes in temperature significantly influence swelling and drug release of these hydrogels. Due to maximum swelling of hydrogels around 40 1C, the P(HEMA/IA) hydrogel containing 5 mol% of IA without and with drug-antibiotic (gentamicin) were investigated at pH 7.40 and in the temperature range 25-42 1C, in order to evaluate their potential for medical applications. r
Radiation Physics and Chemistry, 2003
Hydrogels of poly(N,N 0-dimethylacrylamide-co-2-methoxyethylacrylate) and poly(acrylamide-co-2-methoxyethylacrylate) have been synthesized by radiation polymerization in dimethylformamide solution with trimethylolpropane trimethacrylate as a crosslinker. In this work, some investigations on the in vitro release of gentamicin sulphate, an antibiotic entrapped in the hydrogels, are reported. The kinetics of drug release from hydrogels matrices were examined and the results indicate that the release for the proposed geometry practically occurs in the first 24 h. The fractional cumulative release of the drug from the DMAA/MOEA matrices is linear when plotted against the square root of time, pointing out a Fickian process. On the other hand, AAm/MOEA matrices showed an initial non-Fickian behaviour, probably indicating a comparable rates of Fickian diffusion and polymer relaxation.
Characterisation and controlled drug release from novel drug-loaded hydrogels
European Journal of Pharmaceutics and Biopharmaceutics, 2008
Hydrogel based devices belong to the group of swelling controlled drug delivery systems. Temperature responsive poly(N-isopropylacrylamide)-poly(vinylpyrrolidinone) random copolymers were produced by free radical polymerisation, using 1-hydroxycyclohexylphenyketone as an ultraviolet-light sensitive initiator, and poly(ethylene glycol) dimethacrylate as the crosslinking agent (where appropriate). The hydrogels were synthesised to have lower critical solution temperatures (LCST) near body temperature, which is favourable particularly for 'smart' drug delivery applications. Two model drugs (diclofenac sodium and procaine HCl) were entrapped within these xerogels, by incorporating the active agents prior to photopolymerisation. The properties of the placebo samples were contrasted with the drug-loaded copolymers at low levels of drug integration. Modulated differential scanning calorimetry (MDSC), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and atomic force microscopy (AFM) were used to investigate the influence of the drugs incorporated on the solid-state properties of the xerogels. MDSC and swelling studies were carried out to ascertain their effects on the LCST and swelling behaviour of the hydrated samples. In all cases, drug dissolution analysis showed that the active agent was released at a slower rate at temperatures above the phase transition temperature. Finally, preliminary in vitro cytotoxicity evaluations were performed to establish the toxicological pattern of the gels.