A hydrogel forming system which comprises a hydrophobic macromer with unsaturated
group terminated ends and a hydrophilic polymer which is a polysaccharide (e.g.
dextran) containing hydroxy groups which are reacted with unsaturated group introducing
compound, is convertible by free radical polymerization to form a hydrogel containing
a three dimensional crosslinked polymer network containing hydrophobic and hydrophilic
components. Agent can be entrapped in the polymer network, e.g., drugs, macromolecules
or synthetic or natural polymers, for controlled release therefrom.
