Bioadhesive PAA-PEG-PAA triblock copolymer hydrogels for drug delivery in oral cavity

A series of poly(amidoamine)-poly(ethylene glycol)-poly(amidoamine) (PAA-PEG-PAA) triblock copolymers were designed and prepared to examine the factors affecting their sol-gel transition behavior. The physiochemical properties of the triblock copolymers were characterized by H-1 NMR spectroscopy and gel permeation chromatography. The PAA-PEG-PAA copolymers underwent sol-gel transitions in solution (10-15 wt%) in response to changes in both the pH and temperature. The sol-gel transition phase behavior was controlled by adjusting the molecular weights of the PEG and PAA blocks and changing the PAA-PEG-PAA concentration. These copolymers demonstrated stronger bioadhesive properties than chitosan and poly(acrylic acid) in an aqueous solution. The in vitro release of flubiprofen was controllable using these copolymer hydrogels.