Advancements in the Development of Biostable Polyurethanes

Strategies to design biostable polyurethanes are briefly reviewed to understand the effect of the polyurethane chemical structure on mechanical properties and resistance to degradation based on reported in vitro and in vivo data. In vitro test methods developed to simulate the biological environment and their suitability to screen new materials for oxidative stability are discussed. Major part of the review is devoted to the family of siloxane-based polyurethanes since materials from this family have advanced to clinical application with demonstrated long-term biostability in cardiovascular devices. The morphology and surface properties of siloxanepolyurethanes are also discussed along with a brief overview of reported studies to evaluate comparative stability of polyurethanes formulated using different strategies.