Crosslinked hydrogel copolymers

Abstract

The present invention relates to crosslinked polymers, synthesized through ring-opening polymerization of ethylenically unsaturated epoxides, in combination with α-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(α-hydroxy acid-co-glycidyl methacrylate)-block-poly(ethylene glycol)-block-poly(α-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.

1 . A method for preparing particulates, comprising: 
 (a) preparing a first phase, the first phase comprising an active agent, a copolymer which comprises a randomly distributed ring-opened ethylenically unsaturated epoxide, a ring-opened cyclic ester, and a hydrophilic segment, and a solvent;    (b) preparing a second phase, wherein the first phase is substantially immiscible with the second phase;    (c) combining the first phase and the second phase to form an emulsion; and    (d) extracting solvent from the emulsion using an extraction liquid to thereby form particulates containing the active agent.    
     
     
         2 . The method of  claim 1 , further comprising the step of crosslinking the copolymer.  
     
     
         3 . The method of  claim 1 , wherein the particulates further comprise an excipient.  
     
     
         4 . The method of  claim 1 , wherein the particulates further comprise a second polymer.