A pH‐sensitive water‐soluble N‐carboxyethyl chitosan/poly(hydroxyethyl methacrylate) hydrogel as a potential drug sustained release matrix prepared by photopolymerization technique

Abstract

Biocompatible pH‐sensitive semi‐interpenetration polymeric network hydrogels (semi‐IPN) based on water‐soluble N‐carboxyethyl chitosan (CECS) and 2‐hydroxyethyl methacrylate (HEMA) were synthesized by the photopolymerization technique. pH‐sensitivity, cytotoxicity, morphology, mechanical property, and water state of hydrogel were investigated by a swelling test, methylthiazolydiphenyl‐tetrazolium bromide (MTT) assay, scanning electron microscopy (SEM), universal testing machine, and differential scanning calorimetry (DSC), respectively. The drug release studies were carried out using 5‐Flurouracil as the model drug. The results indicated that the hydrogels were sensitive to pH of the medium and its wet state had good mechanical properties. The results of cytotoxicity and prolonged drug release characteristics revealed the suitability of the hydrogels as drug delivery matrices. The release kinetics was evaluated by fitting the experimental data to standard release equations, and the best fit was obtained with the Higuchi model of the hydrogel. Copyright © 2008 John Wiley & Sons, Ltd.

Synthesis and characterization of chitosan-based hydrogels

“…Samples were prepared as KBr pellet and scanned against a blank KBr pellet background at wavenumber ranging from 4000 to 650 cm −1 with resolution of 4.0 cm −1 . The polymerization process of CS-EGAMA/PEGDMA was monitored by using series real time near infrared spectroscopy (SRTIR, Nicolet 5700 instrument, Thermo Company, USA) to quantify the conversion [1]. The double bond conversion was monitored by the disappearance of =C-H absorption peak area from 6140-6210 cm −1 .…”

“…Hydrogel, which are three-dimensional networks of hydrophilic polymers that are not soluble but swellable in water [1], have attracted extensive attention in biomedical fields as drug deliverers, surgical aids, wound dressing and tissue engineering scaffolds because of their biocompatibility and resemblance to biological tissues [2][3][4][5][6][7]. The physicochemical characteristics of hydrogels depend on the choice of starting polymers and the synthesis procedure.…”

“…Chitosan can be modified easily to form porous hydrogels for existence of reactive amino group [17]. For this reason, photopolymerizated injectable chitosan have received great attention [1]. For chitosan hydrogels by photopolymerization, the temperature and pH can be similar with body environment on the polymerization process.…”

Effect of initial substrate concentrations of the BZ reaction on self-oscillating of polymer chains with Fe(phen)3 catalyst

“…The stimuli-responding mechanisms are mainly based on conformational changes of the polymer chains caused by environmental changes: e.g., temperature, pH, magnetic field, electric field, light, specific chemicals, etc. [5][6][7][8][9][10]. The structural change of polymers is temporary, and on-off switching of stimuli is necessarily needed to repeat the changes.…”

Drug release behavior of a pH/temperature sensitive calcium alginate/poly(N-acryloylglycine) bead with core-shelled structure

“…These hydrogels show the ability of abrupt change including the physical or chemical properties in response to the external stimuli such as pH [2][3][4][5], temperature [4][5][6], electrical field [7,8], magnetic field [9], ion exchange [10]. The unique properties of a smart hydrogel imply that it can be used as a promising material in the biomedical and industrial applications.…”