Nano-hydroxyapatite/cellulose-graft-polyacrylamide biocomposite hydrogels of different molar ratios were prepared to examine their potential application as a carrier for colon targeted drug delivery in vitro. The particle size of the synthesized nano-hydroxyapatite was found to be 122 nm. The swelling behavior of the composite hydrogels was observed in acidic and basic aqueous solution that simulated lower small intestine, colon and stomach fluids. The hydrogel could be applied in drug-delivery systems and acetylsalicylic acid was used as a model compound to test such a possibility. Finally, the synthesized biocomposite hydrogels with the 96.97% maximum encapsulation and 85.67% release efficiency in the basic medium were found to be a suitable candidate to carry and release of colon-targeted drugs. 相似文献
Cyclodextrin‐based controlled delivery materials have previously been developed for controlled release of different therapeutic drugs. In this study, a supramolecular hydrogel made from cyclodextrin‐based macromonomers is subjected to molecular imprinting to investigate the impact on release kinetics and drug loading, when compared with non‐imprinted, or alternately imprinted hydrogels. Mild synthesis conditions are used to molecularly imprint three antibiotics—novobiocin, rifampicin, and vancomycin—and to test two different hydrogel chemistries. The release profile and drug loading of the molecularly imprinted hydrogels are characterized using ultraviolet spectroscopy over a period of 35 days and compared to non‐imprinted, and alternately imprinted hydrogels. While only modest differences are observed in the release rate of the antibiotics tested, a substantial difference is observed in the total drug‐loading amount possible for hydrogels releasing drugs which has been templated by those drugs. Hydrogels releasing drugs which are templated by other drugs do not show improved release or loading. Analysis by FTIR does not show substantial incorporation of drug into the polymer. Lastly, bioactivity assays confirmed long‐term stability and release of incorporated antibiotics. 相似文献
Superabsorbent hydrogels based on the natural polymer chitosan and acrylic acid (CS/AAc) was prepared using 60Co gamma radiation as a source of initiation and crosslinking. The factors, which affect the preparation of CS/AAc hydrogels such as irradiation dose, CS/AAc ratios, and acrylic acid monomer concentrations, to get the best optimum conditions, were investigated. The kinetic studies of the swelling of CS/AAc hydrogel showed that it follows a Fickian type of water diffusion. The Fickian constant value ‘n’ was more than 0.5 with a high swelling capacity of 300 g/g as superabsorbent hydrogel. In addition, the suitability of CS/AAc hydrogel as carrier material for the drug Chlortetracycline-HCl has been investigated by adsorption isotherm studies. The performance of drug release from hydrogel systems, influenced by acrylic acid ratio and the effect of pH of the medium was studied. 相似文献
Summary: Positively charged copolymer hydrogels based on N-isopropyl-acrylamide (NiPAAm) and a cationic surfactant monomer (surfmer) were functionalized upon electrostatic self-assembly of functional organic or inorganic complex counterions in the gel. As cationic surfmers 11-acryloylundecyltrimethylammonium bromide (AUTMAB) or 11-methacryloyl-undecyltrimethylammonium bromide (MUTMAB) were used. The hydrogels were prepared from a micellar aqueous solution of the surfmer and NiPAAm either upon 60Co-gamma irradiation, or upon chemical cross-linking using methylenebisacrylamide as cross-linker and 1,4-diaminobutane as accelerator. Electrostatic self-assembly was facilitated utilizing the thermoresponsive swelling and shrinking of the hydrogel. Several examples of gel functionalization are described such as in-situ preparation of Prussian Blue and Pd0 nanoparticles, and induction of fluorescent properties. The catalytic activity of the palladium-containing gel was studied by investigating the reduction of 4-nitrophenol (4-NP) with sodium borohydride as a model reaction. Fluorescent gels can be prepared upon exchange of bromide against 1-pyrenesulfonate ions in the gel. 相似文献
This study reports a series of novel amino acid based dual‐responsive hydrogels. Prepared by a facile one‐pot 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide (EDC) coupling reaction, the solid content, structure, and mechanical behavior of hydrogels could be easily adjusted by changing the concentrations of the polymers and the crosslinkers. With pH‐responsive anionic pseudo‐peptides as backbones and disulfide‐containing l ‐cystine dimethyl ester as crosslinkers, these hydrogels are able to collapse and form relatively compact structure at an acidic pH, while swelled and partly dissociated at a neutral pH. Further addition of dithiothreitol (DTT) facilitated complete degradation of hydrogels. The high loading efficiency, rapid but complete triggered‐release, and good biocompatibility make these hydrogels promising candidates for oral delivery.
The purpose of the study is to obtain multicomponent polyelectrolyte hydrogels with optimal synergistic properties by combining a modified starch with a synthetic one. Thus, new low‐cost and biocompatible semi‐interpenetrating polymer network (semi‐IPN) hydrogels of carboxymethyl starch and poly(2‐dimethylaminoethyl methacrylate) are prepared and investigated. The synthesized hydrogels are studied with respect to the specific characteristics of the gels: swelling kinetics, thermal analysis, viscoelastic characteristics, and their ability to be used as a matrix in drug delivery systems. Therefore, the semi‐IPN gels are loaded with ibuprofen, followed by additional tests to assess the in vitro drug release. The cytocompatibility of the hydrogels with respect to their composition is evaluated in vitro on fibroblast cell culture. The investigations confirm the obtainment of new semi‐IPN hydrogels with pH and temperature responsiveness, good mechanical strength, and potential for use as drug delivery systems or transdermal patches. 相似文献
