High Strength Biodegradable Tyrosine-Derived Polymers

A class of degradable polyesters derived from tyrosine and other natural metabolites was structurally tuned for the purpose of optimizing mechanical strength parameters (tensile strength, modulus). In previous studies it was demonstrated that this class of polymers was biocompatible and osteoconductive, however, it was felt that if the polymers were to function in high strength load bearing fracture fixation applications, some redesign of the polymeric primary structure was in order.

In this study the polymer primary structure was varied by substituting rigid aromatic or unsaturated structures for the more flexible methylene constructs and by adding groups which would impose non-bonded and cross linked association of polymer chains. Alterations in polymer design were implemented both at the backbone and pendent group level.

These structural changes led to values for mechanical strength parameters which were more than twice the original values. The tensile strength ranged from 37-109 MPa and the modulus ranged from 1.1-3.9 GPa: compared to literature values for �Dacron�; 59-72 MPa and 2.8-4.1 GPa respectively.