Patent ID: 8262723

Claim:
An implantable medical device fabricated from a polymer blend comprising: a biodegradable matrix polymer blended with biodegradable star-block copolymers having at least three arms, wherein the arms include inner segments and outer segments, the inner segments forming a discrete phase within a continuous phase, wherein the blend comprises discrete phase regions dispersed within the continuous phase, the continuous phase including the matrix polymer and the outer segments, wherein the inner segments are elastomeric with a glass transition temperature below body temperature, the discrete phase having a lower modulus than the matrix polymer of the continuous phase, wherein the matrix polymer is glassy with a glass transition temperature above body temperature, wherein the discrete phase increases the toughness of the blend, wherein the inner segments comprise units having acidic degradation products that enhance the degradation rate of the blend, wherein the implantable medical device is a stent scaffolding including a network of interconnecting struts and the scaffolding is made completely out of the blend.