Bioabsorbable polymeric composition for a medical device
A biodegradable and biocompatible nontoxic polymeric composition is provided which includes a base material such as a crystallizable polymer, copolymer, or terpolymer, and a copolymer or terpolymer additive. Medical devices manufactured from the composition are also provided.
1. A method for making a bioabsorbable stent comprising the steps of:
(a) blending a polymer composition comprising a crystallizable bioabsorbable polymer composition, wherein the crystallizable bioabsorbable polymer composition comprises a base polymer comprising a poly(L-lactide) moiety and/or poly(D-lactide) moiety, and/or poly L-lactide-co-PEG moiety, and/or poly D-lactide-co-PEG moiety, linked with a modifying copolymer thereof comprising poly(L-lactide-co-Tri-methylenecarbonate) and/or poly(D-lactide-co-Tri-methylene-carbonate) and/or poly(L-lactide-co-ε-caprolactone) and/or poly(D-lactide-co-ε-caprolactone) in the form of block copolymers or as blocky random copolymers; wherein the chirality of the polylactide segments of the modifying copolymer are opposite to the chirality of the polylactide segments of the base polymer; and
(b) molding or extruding said polymer composition to produce a tube, wherein the polymer composition forms a lactide racemate stereo complex crystal structure between the base polymer and the modifying polymer.
2. The method of claim 1 , further comprising the step of cutting the tube into a scaffold form using a laser after step (b), wherein the scaffold form comprises a cage-like mesh of meandering struts connected to hoop-like rings.
3. The method of claim 2 , wherein the hoop-like rings are positioned at at least one end of the tube.
4. The method of claim 2 , wherein the hoop-like rings are positioned at the middle portion of the tube.
5. The method of claim 2 , wherein the meandering struts comprise a first and second set of meandering struts, wherein (i) the first and second sets of meandering struts alternate in a pattern of first and second meandering struts, (ii) the second meandering struts form a hoop shape after expansion, and (iii) the crystallinity of the second meandering struts after expansion is greater than the crystallinity of the first meandering struts after expansion.