“…Therefore, poly (ethylene glycol) is widely used as a pharmacological polymer with high hydrophilicity, biocompatibility and biodegradability. In recent years, derivative poly (ethylene glycol)-g-derivative chitosan to obtain nanoparticles has been studied by many researchers (Ouchi et al, 1998;Jung et al, 2006) (Park et al, 2008) (Yang et al, 2008b) (Opanasopit et al, 2007). The grafted poly (ethylene glycol) methyl ether onto N-Phthaloyl chitosan chains, aggregated to obtain sphere-like nanoparticles (an et al, 2004).…”