A new generation of poly(lactide/ε-caprolactone) polymeric biomaterials for application in the medical field

Thermoplastic biodegradable polymers displaying an elastomeric behavior are greatly valued for the regeneration of soft tissues and for various medical devices. In this work, terpolymers composed of epsilon-caprolactone (CL), D-lactide (D-LA), and L-lactide (L-LA) were synthesized. These poly(lactid-epsilon-caprolactone) (PLCLs) presented an elevated randomness character (R similar to 1), glass transition temperatures (T-g) higher than 20 degrees C and adjusted L-LA content. In this way, the L-LA average sequence length (lL-LA) was reduced to below 3.62 and showed little or no crystallization capability during in vitro degradation. As a result, the obtained materials underwent homogenous degradation exhibiting K-Mw ranging from 0.030 to 0.066 d(-1) and without generation of crystalline remnants in advanced stages of degradation. Mechanical performance was maintained over a period of 21 days for a rac-lactide-epsilon-caprolactone copolymer composed of similar to 85% D, L-LA and similar to 15% CL and also for a terpolymer composed of similar to 72% L-LA, similar to 12% D-LA and similar to 16% CL. Terpolymers having L-LA content from similar to 60 to 70% and CL content from similar to 10 to 27% were also studied. In view of the results, those materials having CL and D-LA units disrupting the microstructural arrangement of the L-LA crystallizable chains, an L-LA content <72% and a random distribution of sequences, may display proper and tunable mechanical behavior and degradation performance for a large number of medical applications. Those with a CL content from 15 to 30% will fulfill the demand of elastomeric materials of T-g higher than 20 degrees C whereas those with a CL content from 5 to 15% might be applied as ductile stiff materials. (c) 2013 Wiley Periodicals, Inc.