Gel casting of resorbable polymers. 1. Processing and applications.

A gel casting technique based on resorbable, synthetic, alpha-polyesters (or lactide-glycolide polymers) is described for producing medical implants such as bone graft substitutes and timed-release carriers for medication. This solution-based method enables production of thick-section solid and microporous materials, and blending of polymers and particulate fillers. Implant degradation rate, for example, may be adjusted by variation of polymer type, molecular weight range, crystallinity and morphology. Gel casting conditions are reported for solid and microporous materials and processing characteristics are interpreted in terms of established crystallization and dissolution behaviour of polymers.