Poly(malic acid-co-L-lactide) as a superb degradation accelerator for Poly(l-lactic acid) at physiological conditions

The effectiveness of poly(aspartic acid-co-l-lactide) (PAL) and poly(malic acid-co-l-lactide) (PML) oligomers as degradation accelerators for poly(l-lactic acid) (PLLA) was investigated in a phosphate buffer solution at 40 °C. It was found that the hydrolysis rate constant of the PLLA at 20 wt% loading is enhanced 15 times by PAL and 34 times by PML. The superiority of PML to PAL is probably related to its higher ability as acidic catalyst and higher miscibility with PLLA. Since PML and its decomposition products are environmentally safe and biocompatible, the present study demonstrates that PML is a promising biomaterial as a carrier matrix for biopharmaceuticals and for tissue regeneration. Our findings also proved the usefulness of PLLA blends containing a degradation accelerator in applications necessary to tune the degradation rate, since the blends are much easier to tailor the degradation rate compared to conventional PLLA copolymers such as poly(lactide-co-glicolide).