Processing of Resorbable Poly-α-Hydroxy Acids for Use as Tissue-Engineering Scaffolds
Minna Kellomäki and Pertti Törmälä
1. Introduction
1.1. Absorbable Poly-α-Hydroxy Acids
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).………………