Biodegradable medical implants, polymer compositions and methods of use
Inventors
Imran, Mir • Patel, Sanjay • Harris, Joel
Assignees
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Publication Number
US-11642438-B2
Publication Date
2023-05-09
Expiration Date
Abstract
Embodiments of the invention provide compositions including bio degradable polymers, medical implants fabricated from these compositions and methods of using such implants. Many embodiments provide medical implants comprising a first polymer backbone having a first rate of biodegradation and a second polymer backbone having a second rate of biodegradation faster than the first rate. In some embodiments, the second backbone is configured to be replaced by a natural tissue layer. The first backbone provides a scaffold for the implant while the second backbone degrades. This scaffold can enhance mechanical properties of the implant including various aspects of mechanical strength such as tensile, bending, hoop and yield strength; and elasticity. The scaffold also serves to maintain a minimum level of structural support of the implant during the period of degradation of the second backbone or for the entire life of the implant so that the implant does not mechanically fail.
Core Innovation
The invention relates to biodegradable medical implant polymer compositions and their use in the human body where the polymer composition includes a mixture of a first polymer backbone and a second polymer backbone. The first polymer backbone comprises a polyurethane and has a first rate of biodegradation. The second polymer backbone comprises polyglycolic acid (PGA) or polyglycolic lactic acid (PGLA) and has a second rate of biodegradation faster than the first rate.
The polymer backbones are cross-linked to each other such that the second polymer backbone degrades at a faster rate than the first polymer backbone. The faster-degrading second polymer backbone degrades while the first polymer backbone provides a scaffold for the implant that is maintained during degradation. The scaffold is maintained while the second polymer backbone degrades to enable the implant to continue scaffold function.
The invention further includes embodiments where mechanical strength characteristics are maintained to prevent mechanical failure during degradation. The described mechanical strength includes tensile, bending, hoop, yield, elasticity, and fracture resistance. Additional embodiments include cross-linking and tunable degradation rates, and optionally the inclusion of cell-adhesion and migration promoting polypeptides (CAMP peptides) such as MAP and P-15 associated with a faster-degrading layer and/or scaffold.
Claims Coverage
Two independent claims are identified. Both independent claims center on a biodegradable medical implant with cross-linked polyurethane (first backbone) and PGA or PGLA (second backbone) that biodegrade at different rates so that the polyurethane scaffold is maintained while the faster-degrading backbone degrades.
Cross-linked first and second polymer backbones with differential biodegradation rates
A method for using a biodegradable medical implant in the human body by implanting an implant with a polymer composition comprising a mixture of a first polymer backbone and a second polymer backbone cross-linked to the first polymer backbone; the first polymer backbone comprises a polyurethane and has a first rate of biodegradation; the second polymer backbone comprises polyglycolic acid (PGA) or polyglycolic lactic acid (PGLA) and has a second rate of biodegradation faster than the first rate.
Biodegradation so the first polymer backbone provides a maintained scaffold
Degrading the first and second polymer backbones for a period of time at the implant site such that the second polymer backbone degrades at a faster rate than the first polymer backbone such that the first polymer backbone provides a scaffold for the implant that is maintained while the second polymer backbone degrades.
Urethane linkage between first and second polymer backbones
Cross-linking the second polymer backbone to the first polymer backbone by a urethane linkage between an isocyanate side group on the first polymer backbone and a methylene side group on the second polymer backbone, where the first polymer backbone comprises a polyurethane and the second polymer backbone comprises polyglycolic acid (PGA) or polyglycolic lactic acid (PGLA) with a second rate faster than the first rate.
Cross-linked differential biodegradation using a scaffold-forming polyurethane backbone
Degrading the first and second polymer backbones for a period of time at the implant site such that the second polymer backbone degrades at a faster rate than the first polymer backbone such that the first polymer backbone provides a scaffold for the implant that is maintained while the second polymer backbone degrades.
Across the independent claims, the shared inventive concept is differential biodegradation using cross-linked backbones where a polyurethane scaffold-forming backbone is maintained while a PGA/PGLA backbone degrades faster. One independent claim further specifies that cross-linking occurs via a urethane linkage between side groups on the two backbones.
Stated Advantages
Maintains scaffold function while the faster-degrading polymer backbone degrades.
Maintains mechanical strength characteristics during degradation, including tensile, bending, hoop, yield, elasticity, and fracture resistance to prevent mechanical failure during degradation.
Documented Applications
Biodegradable medical implant use in the human body at an implant site.
Vascular grafts including outer/tissue-blood contacting layer architectures and non-thrombogenic blood contacting layers.
Stents.
Surgical meshes and/or membranes.
Intestinal anastomotic grafts.
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