Bioabsorbable blend for temporary scaffolding of the blood vessel wall
Inventors
Kim, Hyung-il • Ishihara, Kazuhiko
Assignees
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Publication Number
US-8772368-B2
Publication Date
2014-07-08
Expiration Date
Abstract
A bioabsorbable blend comprising poly(L-lactide) (PLLA) and a phosphorylcholine group-containing copolymer (PPCP) capable of enduring the mechanical strength of blood vessel walls and applicable for fabricating cardiovascular devices was developed. The blend acts as a scaffold to support blood vessel walls during vascular healing and undergoes biodegradation in vivo after vascular healing is complete. Furthermore, the blend can prevent the formation and adsorption of thrombi.
Core Innovation
The invention relates to a bioabsorbable stent made from a blend that comprises a biodegradable material comprising L-lactic acid and a phosphorylcholine group-containing copolymer (PPCP). The biodegradable material provides a scaffold for temporary support of the blood vessel wall, while the PPCP provides a phosphorylcholine group-containing, blood-compatible composition intended to be absorbable in blood.
The core problem addressed is that bioabsorbable polymers such as poly(L-lactide) can trigger chronic inflammation when used for temporary blood-vessel scaffolding, and this inflammatory response is associated with adverse blood-contact outcomes in cardiovascular devices. The invention positions phosphorylcholine group-containing PPCP as a strategy to suppress protein denaturation, platelet adhesion, and thrombosis, thereby reducing inflammation in blood-contacting environments.
The invention further provides approaches for preparing PPCP and for forming a phosphorylcholine group-rich surface on PLLA while avoiding water-immersion contamination. PPCP is described as being prepared via MPC copolymerization, including MPC-based variants such as PMB30W, PMB80, PMBN, and related MPC copolymer systems.
Claims Coverage
The independent claims cover a bioabsorbable stent formed from a blend including an L-lactic acid biodegradable polymer and a phosphorylcholine group-containing copolymer (PPCP), with additional coverage that PPCP is absorbable in blood. Across the independent claims, the inventive features cluster into two groups: the stent blend composition and the PPCP absorbability in blood.
Bioabsorbable stent from a blend of L-lactic acid biodegradable material and PPCP
A bioabsorbable stent made from a blend comprising a biodegradable material and a phosphorylcholine group-containing copolymer (PPCP), wherein the biodegradable material is a bioabsorbable polymer comprising L-lactic acid.
Bioabsorbable stent with PPCP absorbable in blood
A bioabsorbable stent made from a blend comprising a phosphorylcholine group-containing copolymer (PPCP) that is absorbable in blood.
Claim coverage centers on a bioabsorbable stent comprising a blend of a biodegradable L-lactic acid polymer and a phosphorylcholine group-containing copolymer, with an additional independent coverage that the PPCP is absorbable in blood.
Stated Advantages
Suppresses protein denaturation.
Reduces platelet adhesion.
Suppresses thrombosis.
Suppresses inflammation and chronic inflammatory reaction.
Improves breaking strength while not significantly changing Young’s modulus.
Provides stable biodegradation behavior (mass change) over incubation.
Documented Applications
Temporary blood-vessel scaffolding using a bioabsorbable stent comprising a PLLA/PPCP-type blend.
Cardiovascular devices including stents where reduced platelet adhesion, thrombosis, and inflammation are desired.
In vivo evaluation using rat abdominal aorta implantation (bioabsorbable stent context).
Mentioned compatibility with drug-eluting stent contexts (ENDEAVOR (zotarolimus-eluting) and Cypher (sirolimus-eluting)) in the described device landscape.
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