Analysis of poly(ethylene glycol) tethered poly(acrylic acid) networks for mucoadhesive applications

Graft copolymer networks of poly(acrylic acid) (PAA) containing well characterized tethers of high molecular weight poly(ethylene glycol) (PEG) were prepared using free radical solution UV-polymerization. This was carried out with acrylic acid (AA), monomethacrylate PEG with a molecular weight of 2000 and tetraethyleneglycol dimethacrylate as a crosslinking agent. The copolymers were prepared in different molar ratios. The high molecular weight PEG was incorporated to improve mucoadhesion through interpenetration and as a result improve residence time of the carrier and absorption at the drug delivery site. The dynamic swelling parameters were determined in buffer solutions containing NaCl at different pH. The mucoadhesive properties were tested by bringing the copolymer into contact with mucin solution and determining the work of adhesion through the use of an Instron tensile testing machine. Results suggest that these copolymers are exceptional protein delivery candidates due to their pH-sensitivity and controllable swelling behavior. However, the addition of PEG 2000 tethers has shown to deviate from the synergistic effect of the PAA hydrogen bonding and PEG interpenetration by decreasing the mucoadhesive properties of the hydrogel.