Phosphate crosslinked pectin based dual responsive hydrogel networks and nanocomposites: Development, swelling dynamics and drug release characteristics.

Potential dual responsive hydrogel networks (PPAD) are fabricated from pectin, poly((2-dimethylamino)ethyl methacrylate)) and phosphate crosslinker bis[2-methacryloyloxy] ethyl phosphate (BMEP) by a simple free radical polymerization. These hydrogel networks are successfully utilized for encapsulation of an anti-cancer drug, 5-fluorouracil (5-FU) and also employed as versatile platforms for production of silver nanoparticles. Fabricated hydrogel networks and silver nanocomposites were characterized by FTIR, SEM, EDX, TEM, DLS, DSC, TGA and XRD. Different polymer network parameters such as MC¯, χ, ξ and υe and diffusion constant (D) were evaluated to assess the drug release profile. The 5FU loaded PPAD hydrogels were used to perform in vitro release studies in both gastric and intestinal conditions of GIT (pH 1.2 & pH 7.4) at two different temperatures (25 and 37°C). On the other hand various kinetic models (zero, first, Higuchi & Koresmeyer-Peppas) have also been employed to fit drug release profile. In addition, the antibacterial activity of PPAD silver nanocomposites were tested against four bacterial species Escherichia coli (-ve), Klebsiella pneumoniae (-ve), Bacillus cereus (+ve) and Staphylococcus aereus (+ve) using zone of inhibition test.