Chemical features of the synthesis, degradation, molding and performance of poly(lactic-co-glycolic) acid (PLGA) and PLGA-based articles

Among other biodegradable polymers, poly(lactic-co-glycolic acid)s (PLGAs) are promising basic materials for the development of composites for tissue engineering and orthopedics. Adjustable biodegradability is a key advantage of PLGAs, their microstructure and molecular weight characteristics determine thermal and hydrolytic stability, biocompatibility and physico-mechanical properties of PLGA-based articles. These characteristics depend on the methods of copolymer preparation including commonly used polycondensation and ring-opening polymerization, as well as newly developed segmer assembly polymerization approach. In the present work, we describe and discuss the synthesis of PLGAs (including monomer preparation), determination of the microstructure of PLGAs with different comonomer ratios and sequences, as well as issues of mechanical characteristics, thermal stability and hydrolytic degradation of PLGAs. A special attention is given to the melt molding of PLGAs in preparation of the specimens for laboratory testing and production of the biomedical articles. The data relating to biocompatibility of PLGA articles and their performance in vivo and in patient are also summarized and discussed. In conclusion, we briefly discuss the current limitations and future directions for the further development of PLGAs and PLGA-based composite materials with the use of undervalued methyl glycolide comonomer, synthetic inorganic fillers and polymer compatibilizers.