Polymers for implantable devices exhibiting shape-memory effects

摘要

The present invention is directed to polymeric compositions comprising a biodegradable copolymer that possesses shape-memory properties and implantable devices (e.g., drug-delivery stents) formed of materials (e.g., a coating) containing such compositions. The polymeric compositions can also contain at least one non-fouling moiety, at least additional biocompatible polymer, at least one biobeneficial material, at least one bioactive agent, or a combination thereof. The polymeric compositions are formulated to possess good mechanical, physical and biological properties. Moreover, implantable devices formed of materials comprising such compositions can be delivered to the treatment site in a conveniently compressed size and then can expand to dimensions appropriate for their medical functions.

主权项

1. A composition comprising a biodegradable copolymer comprising at least two segments A and B, wherein:
the A segment has a Tg or Tm in the range from about 50° C. to about 300° C. and is made from at least one diisocyanate and at least one diol, diamine or dithiol chain extender; the B segment has a Tg or Tm in the range from about 30° C. to about 100° C. and is derived from a polymer containing at least one hydroxyl, amino or thiol end group; the Tg or Tm of the A segment is at least about 20° C. greater than the Tg or Tm of the B segment; the A and B segments each independently have a polymer number-average molecular weight (Mn) from about 0.4, kDa to about 500, kDa;and wherein:
the composition displays at least one shape-memory effect, and a permanent shape of the composition is obtained when the temperature of the composition is equal to or greater than the Tg or Tm of the B segment; wherein at least one dihydroxyaryl group is conjugated to the end(s) of the copolymer.