One‐pot synthesis in aqueous system for water‐soluble chitosan‐graft‐poly(ethylene glycol) methyl ether

Chitosan is functionalized with poly(ethylene glycol) methyl ether (mPEG) at the amino and hydroxyl groups via a single step reaction in a homogeneous aqueous system. A chitosan aqueous solution obtained from the mixture of chitosan and hydroxybenzotriazole (HOBt) in water is a key factor in providing mild conditions to conjugate mPEG by using a carbodiimide conjugating agent. The reaction at ambient temperature for 24 h gives chitosan‐g‐mPEG with water solubility with mPEG content as high as 42%. This work demonstrates that a water‐soluble chitosan–HOBt complex is an effective system for the preparation of chitosan derivatives via the aqueous system without the use of acids or organic solvents. © 2006 Wiley Periodicals, Inc. Biopolymers 82:580–586, 2006 This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com