A carrier and a method for preparing it are provided for use in the delivery
therapeutic agents. A polysaccharide is reacted with an oxidizing agent to open
sugar rings on the polysaccharide to form aldehyde groups. The aldehyde groups
are reacted to form covalent oxime linkages with a second polysaccharide and each
of the first and second polysaccharide is selected from the group consisting of
hyaluronic acid, dextran, dextran sulfate, chondroitin sulfate, dermatan sulfate,
keratan sulfate, heparan, heparan sulfate and alginate.