Synthetic biodegradable medical polyesters acid /poly polymers

Common biodegradable polymers for medical devices are constructed from synthetic linear aliphatic polyesters. One material commonly used for internal sutures is poly(glycolic acid) (PGA). PGA is synthesized from the dimer of glycolic acid (Fig. 13.1.l). 1... 

Poly(L-lactide) (PLLA) is a biodegradable aliphatic polyester produced by ring-opening polymerization of lactide (i.e., with cyclic dimer of lactic acid) or by polycondensation of lactic acid. Although PLLA is a synthetic polymer, it is considered a renewable and bio-based plastic because its raw material lactic acid is synthesized from biomass or renewable resources such as sugars and starch. PLLA has some properties that are similar to some petroleum-based plastics, thereby making it suitable for a variety of applications in the medical, textile, and packaging industries. 

There are many polymers that are suitable for the production of nanoparticles employed for drug delivery, which can generally be divided into two groups natural polymers, e.g., polysaccharides (chitosan), proteins (albumin, gelatin), as well as synthetic polymers, e.g., polyesters (poly(lactic add), poly(glycolic add), poly(hydroxy butyrate), poly-e-caprolactone, poly-p-malic add, poly(dioxanones)) polyanhydrides (poly(adipic add)) polyamides (poly(amino acids)) phosphorous-based polymers (polyphosphate) poly(cyano acrylates) polyurethanes polyortho esters and polyacetals. Extreme attention has to be paid to the biodegradability and biocompatibility of the polymers. It is essential that polymers used for medical applications are not detrimental for the tissue or cells and that they can be easily decomposed into simple harmless molecules and eliminated by the human body [ 18-22]. 

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