Synthetic bioresorbable polymers poly

One of the major classes of synthetic bioresorbable polymers is that of aliphatic polyesters or poly(a-hydroxy acids). Poly(a-hydroxy acids) such as PGA, poly(lactic acid) (PLA) stereoisomers poly(L-lactic acid) (PLLA) and poly(D-lactic acid), and pol-y(lactic-co-glycolic acid) (PLGA) copolymers are the most widely used and most popular bioresorbable polymers since they received Food and Drug Administration (FDA) approval for clinical use in humans in different forms (eg, fibers for sutures, injectable forms) (Nair and Laurencin, 2007). These polymers are commonly used in regenerative medicine applications. An example is the InQu Bone Graft Extender Substitute (ISTO Technologies), an osteoconductive biosynthetic product used as bone graft substitute in the skeletal system to support new bone formation. The resorption rate of... 

Because of such complex requirements, the number of synthetic bioresorbable polymers for practical use is limited. This must have been the limitation faced by nature too since all life on earth is based on only three polymeric backbones, namely, polynucleotide, poly(a-amino acid), and polysaccharide chains [11]. For the same reasons, synthetic bioresorbable polymers have been restricted only to certain classes of polymers and till now only a few of them have been approved by the FDA for certain specific applications. 

Poly(glycolic acid) (PGA) is one of the first bioresorbable polymers investigated for biomedical applications. Dexon , the first biodegradable synthetic suture to be approved by the Food and Drug Administration (FDA) in 1969, was based on... 

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