Processing of Resorbable Poly--Hydroxy Acids for Use as Tissue-Engineering Scaffolds

Poly (α-hydroxyacids) were found to be bioabsorble and biocompatible in the 1960s (1 ,2 ). They are the most widely known, studied and used bioabsorbable synthetic polymers in medicine. Polyglycolide (PGA) and poly-l -lactide (PLLA) homopolymers and their copolymers (PLGA), as well as polylactic acid stereocopolymers produced using l -, d -, or DL -lactides and rasemic polymer copolymer PLDLA are all poly (α-hydroxyacids) (3 ). Poly (α-hydroxy acids) can be polymerized via condensation, although only low mol-wt polymers are produced. In order to obtain a higher mol wt and thus mechanical strength and longer absorption time, the polymers are polymerized from the cyclic dimers via ring-opening polymerization using appropriate initiators and co-initiators. The most commonly used initiator is stannous octoate (2 ,3 ).