Bioabsorbable blend for temporary scaffolding of the blood vessel wall
Inventors
Kim, Hyung-il • Ishihara, Kazuhiko
Assignees
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Publication Number
US-9138511-B2
Publication Date
2015-09-22
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 provides a bioabsorbable vascular device whose body is made from a blend comprising a biodegradable material and a phosphorylcholine group-containing copolymer (PPCP). The biodegradable material is a bioabsorbable polymer comprising L-lactic acid (poly(L-lactide) (PLLA)). The vascular device is configured to maintain mechanical strength as a temporary blood-vessel-wall scaffold and to biodegrade in vivo after healing.
The invention uses PPCP in order to form a phosphorylcholine-rich surface on the bioabsorbable vascular device, which is described as reducing platelet adhesion and thrombosis risk. A phosphorylcholine-rich surface and the rationale for MPC/phosphorylcholine blood compatibility are described, including surface verification by X-ray photoelectron spectroscopy (XPS) showing phosphorylcholine surface signals and reduced platelet adhesion.
In the described embodiments, the blend includes PLLA and an example PPCP identified as PMB30W, and preferred blend ratios are described as about 0.5–8 wt% PPCP within the blend. The document further discloses solvent-casting/blending approaches to fabricate scaffold structures such as tubes and cast films, and also describes alternative PPCP copolymer options including PMBAc, PMBN, PMB80, and PMON.
Claims Coverage
The document provides two independent claims directed to a bioabsorbable vascular device with a blend body that includes PPCP, and one independent claim further specifies that the PPCP is absorbable in blood. Across the independent claims, the inventive subject matter centers on combining an L-lactic-acid biodegradable polymer (PLLA) with a phosphorylcholine-group-containing copolymer (PPCP) in a vascular device body.
Blend of biodegradable polymer with phosphorylcholine copolymer
The body of the bioabsorbable vascular device is 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.
Phosphorylcholine copolymer absorbable in blood
The body of the bioabsorbable vascular device is made from a blend, the blend comprising a phosphorylcholine group containing copolymer (PPCP) that is absorbable in blood.
Overall, claim coverage is centered on a bioabsorbable vascular device body formed as a blend of an L-lactic-acid biodegradable polymer (PLLA) and a phosphorylcholine group-containing copolymer (PPCP), with one independent claim further requiring that the PPCP is absorbable in blood.
Stated Advantages
Maintains mechanical strength as a temporary blood-vessel-wall scaffold.
Forms a phosphorylcholine-rich surface to reduce platelet adhesion and thrombosis risk.
Biodegrades in vivo after healing.
Reduced platelet adhesion is reported.
Improved breaking strength for PLLA/PPCP blends is reported.
Slow/controlled degradation behavior is described.
Phosphorylcholine surface signals are stable.
Documented Applications
Temporary blood-vessel-wall scaffold in cardiovascular devices such as stents, for mitigation of stent thrombosis risk.
Vascular connection devices, artificial vessels, ventricular assist devices, hemopurification membranes, and catheters.
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