Preparation and characterization of poly(ethylene glycol)-crosslinked reacetylated chitosans

Poly(ethylene glycol) (PEG) dialdehyde diethyl acetals of different molecul ar sizes were synthesized and used to generate in situ PEG dialdehydes for the crosslinking of partially reacetylated chitosan via Schiff reaction and hydrogenation of the aldimines. The water-soluble products obtained were i nstrumentally characterized. Upon freeze-drying, they aggregated to yield i nsoluble soft and spongy biomaterials, that swelled immediately upon contac t with water. When exposed to papain and lipase, at physiological pH values , progressive dissolution of the biomaterials was observed, but no dissolut ion took place with lysozyme, collagenase and amylase. They were found to b e biocompatible towards Caco-2 cells. These crosslinked partially acetylate d chitosans seem suitable for medical items when prompt resorption is sough t. (C) 2000 Elsevier Science Ltd. All rights reserved.