| Crosslinked three-dimensional networks of methacrylic acid grafted with poly(ethylene glycol) and acrylic acid grafted with poly(ethylene glycol) were prepared for use as oral insulin delivery devices. The copolymers were synthesized via free-radical polymerization. Two methods of polymerization were used, solution/dispersion to prepare copolymer gel nanospheres and in situ bulk polymerization of thin films that were crushed to obtain copolymer gel microparticles.; The average particle diameter of the copolymer gel nanospheres at various physiologically relevant pH values was characterized using photon correlation spectroscopy. The size of the copolymer gel nanospheres dramatically increased as the surrounding pH rose above the pKa of the network. The copolymer gel nanospheres were observed with cryogenic scanning electron microscopy to determine shape and population characteristics. The copolymer nanospheres were spherical in shape and monodisperse. |
