Symmetrical biodegradable crosslinkers for use in polymeric devices

There is a need for biodegradable hydrogels that deteriorate at defined rates under physiological conditions for use in engineered tissue constructs and drug delivery. These hydrogels should contain components that are readily synthesized, biocompatible and easily incorporated into hydrogel networks. This need was addressed through a judiciously designed series of crosslinkers composed of symmetrical oligo-glycolate and oligo-lactate esters terminated with vinylic moieties (1). These materials were incorporated into poly(HPMA) networks via free-radical polymerization. This work describes the preparation of symmetrical, lactate and glycolate ester based crosslinking agents and their incorporation into a hydrogel network composed of 2-hydroxypropyl methacrylamide (HPMA). By varying the number of lactic and glycolic acid residues (n = 0, 1, 2) within the crosslinker, the rate of hydrolytic degradation of the gel can be controlled.