A method for synthesizing a medical grade biodegradable material, poly(lactic-co-glycolic acid), copolycondensation of lactic acid and glycolic acid catalyzed by biomass creatinine. The present invention uses commercialized creatinine (a type of biomaterial organic guanidine compounds—the arginine metabolite creatinine (CR) in human body) as the catalyst and industrial lactic acid (LA, mass content 85%, aqueous solution) and glycolic acid (GA, 95%) as the monomer to synthesize the high biosafety of medical poly(lactic-co-glycolic acid) in terms of two steps polycondensation without solvent. The method of the present invention has the following characters: green technology is used, raw materials required are low in costs, operation is simple and convenient, and it is easy for industrialization the catalyst, creatinine, used in the invention has high biocompatibility and biosafety, and no cytotoxicity the poly(lactic-co-glycolic acid) synthesized is free of any metal and other toxic residues Further, the molecular weight distribution for all synthesized products is narrow and the molecular weight is controllable within 1.8-17.7×104 and the poly(lactic-co-glycolic acid) synthesized is suitable for use as implantable material for hard tissue repair, surgical sutures, and the carrier for targeting drugs and controlled release drugs.
