Bioabsorbable Polymeric Compositions and Medical Devices
The bioabsorbable polymers and compositions of the present invention may be formed into medical devices such as stents that can be crimped onto a catheter system for delivery into a blood vessel. The properties of the bioabsorbable polymers allow for both crimping and expansion of the stent. The crystal properties of the bioabsorbable polymers may change during crimping and/or expansion allowing for improved mechanical properties such as tensile strength and slower degradation kinetics. Typically, bioabsorbable polymers comprise aliphatic polyesters based on lactide backbone such as poly L-lactide, poly D-lactide, poly D,L-lactide, mesolactide, glycolides, lactones, as homopolymers or copolymers, as well as formed in copolymer moieties with co-monomers such as, trimethylene carbonate (TMC) or ε-caprolactone (ECL).
1 . A composition comprising a blend formed from poly-L-lactide, poly-D-lactide or mixtures thereof and a copolymer moiety comprising poly-L-lactide or poly-D-lactide linked with β-caprolactone or trimethylcarbonate wherein, the poly-L-lactide or poly-D-lactide sequence in the copolymer moiety is random with respect to the distribution of ε-caprolactone or trimethylcarbonate and where the wide-angle X-ray scattering (WAXS) exhibits 20 values of about 16.48 and about 18.76.
2 . The composition of claim 1 wherein the co-polymer moiety comprises poly-L-lactide or poly-D-lactide linked with ε-caprolactone.
3 . The composition of claim 2 wherein the polymer moiety comprises poly-L-lactide.
4 . The composition of claim 2 wherein the polymer moiety comprises poly-D-lactide.
5 . The composition of claim 1 wherein the co-polymer moiety is poly-L-lactide or poly-D-lactide linked with TMC and the molecular weight of the co-polymer ranges from about 1.2 IV to about 2.6 IV.
6 . The composition of claim 2 wherein the molecular weight of the co-polymer ranges from about 0.8 to about 6.0.
7 . The composition of claim 1 wherein the WAXS 2θ values further comprise peaks at about 11.92, about 20.66, about 22.24 and about 28.84.
8 . The composition of claim 1 comprising a blend having about 20%-45% (w/w) poly-L-lactide, about 35% (w/w) to about 50% (w/w) poly-D-lactide and about 10% (w/w) to about 35% (w/w) poly L-lactide-co-TMC or poly-L-lactide-ε-caprolactone.
9 . The composition of claim 1 wherein the poly-L-lactide or poly-D-lactide ranges from about 20% (w/w) to about 95% (w/w).
10 . The composition of claim 9 wherein the poly-L-lactide or poly-D-lactide ranges from about 50% (w/w) to about 95% (w/w).
11 . The composition of claim 10 wherein the poly-L-lactide ranges from about 60% (w/w) to about 95% (w/w).
12 . The composition of claim 11 wherein the poly-L-lactide ranges from about 70% (w/w) to about 80% (w/w).
13 . The composition of claim 1 wherein greater than 7 L-lactides or D-lactides are arrayed sequentially in the copolymer moiety.
14 . A composition comprising a blend formed from poly-L-lactide, poly-D-lactide or mixtures thereof and a copolymer moiety comprising poly-L-lactide or poly-D-lactide linked with ε-caprolactone or trimethylcarbonate wherein, the poly-L-lactide or poly-D-lactide sequence in the copolymer moiety is random with respect to the distribution of ε-caprolactone or trimethylcarbonate, wherein there is at least about 95% (w/w) amorphous material in the composition.
15 . The composition of claim 14 wherein there is at least about 98% (w/w) amorphous material.
16 . The composition of claim 15 wherein there is at least about 99% (w/w) amorphous material.
17 . The composition of claim 1 wherein percent crystallinity ranges from about 0% (w/w) to about 10% (w/w).
18 . The composition of claim 1 wherein the percent crystallinity ranges from about 20% (w/w) to about 70% (w/w).
19 . The composition of claim 18 wherein the percent crystallinity ranges from about 30% (w/w) to about 60% (w/w).
20 . The composition of claim 19 wherein the percent crystallinity ranges from about 30% (w/w) to about 60% (w/w).
21 . A composition comprising a blend formed from poly-L-lactide, poly-D-lactide or mixtures thereof and a copolymer moiety comprising poly-L-lactide or poly-D-lactide linked with ε-caprolactone or trimethylcarbonate wherein, the poly-L-lactide or poly-D-lactide sequence in the copolymer moiety is random with respect to the distribution of ε-caprolactone or trimethylcarbonate and where the wide-angle X-ray scattering (WAXS) exhibits 20 values of about 16.65 and about 18.96.
22 . The composition of claim 21 wherein the WAXS 20 values further comprise about 12.00, about 14.80, about 20.67, about 22.35, about 23.92, about 24.92, about 29.16 and about 31.28.
23 . The composition of claim 1 wherein the T m peaks occur at about 180° C. and about 217° C.
24 . The composition of claim 21 wherein the T m peaks occur at about 178° C. and about 220° C.
25 . The composition of claim 21 wherein about T g is 61° C. and about 128° C.