ABSTRACT
Hydrogels in which poly(acryl amide)/lignosulfonic acid (AAm/LSA) crosslinked with N,N’-methylene bis acrylamide, were prepared by using a redox polymerization technique. These hydrogel networks can act as excellent nano reactors for producing and stabilizing the metal nanoparticles. The current methodology allows us to entrap metal nanoparticles throughout hydrogel networks via AAm/ LSA chains. The synthesized silver nano composite hydrogels (Ag-NCHs) were fully characterized by using UV-visible spectroscopy; Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD) studies, scanning electron microscopy (SEM), dynamic light scattering (DLS) analysis and Transmission electron microscopy (TEM). The chemical structure and crosslinking in AAm/LSA hydrogels and Ag-NCHs matrix was analyzed by FTIR. SEM and TEM measurements suggested the spherical structure of the silver particles with smooth surface and size of these particles confirmed by DLS. Crystalline nature of the nanoparticles was confirmed by XRD and electron diffraction measurements. Swelling studies were performed in water with the help of an empirical equation to investigate the diffusion mechanism. The developed Ag-NCHs were evaluated for preliminary antibacterial applications against E.coli and Bacillus.
ABSTRACT
In recent years azo functionalized polymeric hydrogels are very interesting; it is due to their promising applications in various fields especially in the colon drug delivery. 4-Hydroxyphenylazo-3-N-(4-hydroxyphenyl) maleimide (HPM) was synthesized and used for development of hydrogels by free radical polymerization with acrylamide (Am) and N,N-methylene bis acrylamide. Synthesized poly(Am-co-HPM) (PAH) hydrogels were used for encapsulation of 5-fluorouracil (5-FU) an anticancer drug. Structural, thermal, morphological and drug distribution of PAH hydrogels were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction techniques, respectively. Maximum percentage of encapsulation efficiency i.e. 78.25±1.3 was observed for AZ1 PAH hydrogels. 5-FU release studies were performed by in vitro method in simulated gastro intestinal fluids (pH 1.2 & 7.4). To support the 5-FU release mechanism from PAH hydrogels, swelling and deswelling kinetics were studied in doubly distilled water.
ABSTRACT
Biodegradable sodium alginate-g-poly (vinyl caprolactam) synthesized by graft copolymerization of N-vinyl caprolactam (VCL) on to sodium alginate (NaAlg) via free radical initiation mechanism using a redox initiation system. Grafting (%), efficiency (%), and conversion (%) were all found to depend on the content of potassium persulfate (KPS), VCL reaction temperature and time. The maximum % of grafting was ascertained to be 251 at the optimum conditions of 65 oC reaction temperature, 180 min of reaction time, 1.1098X10-3 mol of KPS and 7.1844X10-3 mol of VCL. Evidence of graft copolymerization was obtained by fouriertransform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Further, graft copolymer was used for preparation of microgels (MGs) using Ca+2 as a crosslinking agent. SEM results showed that the MGs are spherical in structure with smooth surface. The effects of pH and temperature on the swelling behaviour of MGs were studied and ascertained that they were sensitive to both pH and temperature. 5-FU drug was successfully loaded in to these MGs and encapsulation efficiency was found 84%. The release of 5-FU was systematically investigated as a function of temperature, pH, amount of crosslinker and % of drug loading concentration. The results indicate that the responsive MGs have the potential to be used as an effective pH and temperature controlled delivery of 5-FU for more than 12 h.
ABSTRACT
Chitosan and guargum-gt-acrylamide (CH-GG-g-AAm) semi interpenetrating microspheres (semi IPNMs) were prepared by water-in-oil (w/o) emulsion cross linking method using glutaraldehyde as a crosslinker. 5-fluorouracil (5-FU) is an anticancer drug was successfully loaded in these semi IPNMs. X-ray diffraction (XRD) and differential scanning calorimetric (DSC) examined the crystalline nature of drug after encapsulation into semi IPNMs. Scanning electron microscopy (SEM) shows the formation of semi IPNMs is spherical with size around 200 m. The encapsulation efficiency of 5-FU was achieved 58%. In-vitro release studies were performed basic (pH 7.4) buffer medium. The release patterns depend on graft polymer composition, effect of cross linker and drug content in the polymer matrices. In vitro release studies indicated the release of 5- FU more than 12 hours.