Polylactic acid(PLA) was introduced in 1966 for degradable surgical implants. Hydrolysis yields lactic acid, a normal intermediate of carbohydrate metabolism. Polyglycolic acid sutures have a predictable degradation rate which coincides with the healing sequence of natural tissues.
Polylactic acid, also known as polylactide, is prepared from the cyclic diester of lactic acid (lactide) by ring-opening addition polymerization. Pure DL-lactide displays greater bioresorbability, whereas pure poly-Llactide is more hydrolytically resistant.
The actual time required for poly-L-lactide implants to be completely absorbed is relatively long, and depends on polymer purity, processing conditions, implant site, and physical dimensions of the implant.
