Hydrolytic degradation of cross-linked irradiated PLLA and PLGA polymers

Abstract

The purpose of the is study is to examine the hydrolytic degradation of irradiated crosslinked poly(L-lactide) (PLLA-ir) and poly(lactide-co-glycolide) (PLGA-ir). It was observed that upon crosslinking, the samples demonstrated enhanced mechanical properties and thermal stability. They also exhibited very insignificant mass loss and water uptake over a degradation period of 12 weeks. There was notable loss in the gel fraction formed, although it was not enough to affect the physical state of the polymers. The polymers were able to retain its geometrical structure post-degradation. PLLA-ir and PLGA-ir were also observed to be able to retain much of their mechanical properties (yield strength, Young’s modulus and strain at yield) after hydrolysis, although the polymers were more brittle than before irradiation. There was also no observable change in the thermal stability of the polymers as they were degraded. Given its superior resistance to hydrolytic degradation, crosslinked PLLA-ir and PLGA-ir could potentially be ideal choices for biomedical applications like fixation or load bearing devices, over an implantation period of 3 to 6 months.