The present invention relates to crosslinked polymers, synthesized through
ring-opening polymerization of ethylenically unsaturated epoxides, in
combination with .alpha.-hydroxy acids using a hydrophilic macroinitiator,
such as poly(ethylene glycol), to form substituted copolymers having
ethylenically unsaturated functionality randomly distributed along the
polyester polymer backbone. That copolymer is subsequently crosslinked to
form a hydrogel network. More particularly, the present invention relates
to the synthesis of biodegradable poly(.alpha.-hydroxy acid-co-glycidyl
methacrylate)-block-poly(ethylene glycol)-block-poly(.alpha.-hydroxy
acid-co-glycidyl methacrylate) copolymers, which are subsequently
crosslinked to form hydrogel networks. The invention also relates to the
use of these hydrogel networks in various applications, in particular, for
the controlled release of drugs and proteins.
