Dual Responsive Pectin Hydrogels and Their Silver Nanocomposites: Swelling Studies, Controlled Drug Delivery and Antimicrobial Applications

Novel dual responsive pectin hydrogels composed from poly(acrylamidoglycolic acid-co-vinylcaprolactam)/Pectin (PAV-PC) and also PAV-PC, hydrogels are used as templates for the production of silver nanoparticles. 5-Fluorouracil is an anticancer drug and has been loaded in situ into PAV-PC hydrogels. Structure and morphology characterization of PAV-PC hydrogels were investigated by fourier transform infrared spectroscopy, differential scanning calorimetry, thermo gravimetric analysis, X-ray diffraction studies, scanning electron microscopy and transmission electron microscopy. The results revealed a molecular level dispersion of the drug in PAV-PC hydrogels. In vitro release of 5-fluorouracil from the PAV-PC hydrogels has been carried out in GIT fluids as well as in various temperatures. 5-Fluorouracil released from PAV-PC hydrogels was 50% at pH 1.2, and 85% at pH 7.4 within 24 h. The release profile was characterized with PAY-PC hydrogels and initial burst effect was significantly reduced in two buffer media (1.2 and 7.4), followed by a continuous and controlled release phase, the drug release mechanism from polymer was due to Fickian diffusion. In situ fabrication of silver nanoparticles inside the hydrogel network via the reduction of sodium borohydrate by PAV-PC chains led to hydrogel nanocomposites. The diameter of the nanocomposites was about 50-100 urn, suitable for uptake within the gastrointestinal tract due to their nanosize range and mucoadhesive properties. These nanocomposite PAY-PC hydrogels showed strong antimicrobial activity towards Bacillus subtilis (G+ve) and Escherichia coli (G-ve).