We
report a promising strategy based on chitosan (CS) hydrogels
and dual temperature- and pH-responsive poly(N-isopropylacrylamide-co-methacrylic acid) (PNIPAM-co-MAA) microgels
to facilitate release of a model drug, moxifloxacin (MFX). In this
protocol, first, the microgels were prepared using a free radical
copolymerization method, and subsequently, these carboxyl-group-rich
soft particles were incorporated inside the hydrogel matrix using
an EDC-NHS amidation method. Interestingly, the resulting microgel-embedded
hydrogel composites (MG-HG) acting as a double barrier system largely
reduced the drug release rate and prolonged the delivery time for
up to 68 h, which was significantly longer than that obtained using
microgels or hydrogels alone (20 h). On account of the dual-responsive
features of the embedded microgels and the variation of water-solubility
of drug molecules as a function of pH, MFX could be released in a
controllable manner by regulating the temperature and pH of the delivery
medium. The release kinetics followed a Korsmeyer-Peppas model, and
the drug delivery mechanism was described by Fickian diffusion. Both
the gel precursors and the hydrogel composites exhibited low cytotoxicity
against mammalian cell lines (HeLa and HEK-293) and no deleterious
hemolytic activity up to a certain higher concentration, indicating
excellent biocompatibility of the materials. Thus, the unprecedented
combination of modularity of physical properties caused by soft particle
entrapment, unique macromolecular architecture, biocompatibility,
and the general utility of the stimuli-responsive polymers offers
a great promise to use these composite materials in drug delivery
applications.
Complexation of some water soluble nonionic polymers, namely, polyvinylalcohol (PVA), polyvinylpyrrolidone (PVP), and hydroxypropyl cellulose (HPC), with iodine has been studied in aqueous and aqueous sodiumdodecylsulfate (SDS) solution. While the complexation was indicated by a red shift of the tri-iodide band in case of PVP or HPC, the PVA-iodine complex showed its characteristic band around 500 nm. It was observed for the first time that presence of SDS led to complete break down of the PVA-iodine complex and its characteristic blue color. The presence of monomers of SDS, however, appeared to favor the formation of the iodine complex with PVP or HPC. Addition of n-propanol, which is known to prevent the formation of gels or microgels in polymer solutions, was found to enhance the polymer-iodine complex. Gels of pure HPC and HPC with iodine both in presence and absence of SDS have been prepared and studied.
In this study, environmentally friendly hydrogels prepared from hydroxy propyl cellulose hydrogels blended with poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) were employed to absorb selected metal ions of Cu and Fe to find potential applications in removal of metal ion from water or in wastewater treatment. Highest adsorption capacity of hydroxy propyl cellulose hydrogels blended with PVA or PVP is shown at 0.04 % (w/v) of the metal ion solutions. Hydroxy propyl cellulose hydrogel when blended PVA has shown greater adsorption of Fe(III) ion than Cu(II) ion at higher pH. Hydroxy propyl cellulose hydrogel when blended with PVP also showed maximum adsorption capacity rather than PVA blended hydrogel.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.