A Library of L-Tyrosine-Derived Biodegradable Polyarylates for Potential Biomaterial Applications, Part I: Synthesis, Characterization and Accelerated Hydrolytic Degradation

Abstract

A combinatorial library of biodegradable polyarylates derived from L-tyrosine was synthesized and characterized. These polyarylates are A–B-type co-polymers consisting of a cyclic dipeptide and a diacid. General structure–property correlations were established by comparing aryl diacid co-polymers and aliphatic diacid co-polymers. The synthesized polymers were characterized by FT-IR, ¹H-NMR, ¹³C-NMR for their chemical structure, by DSC and TGA for their thermal characteristics and by GPC for their molecular weight distribution. The T _g of polymers decreased and water absorption increased with increasing number of methylene groups in the polymer backbone. Using a cyclic peptide derived from L-tyrosine as co-monomer we obtained optimum bioactivity and biocompatibility. Combinatorial approaches of designing material increased effectively the number of available degradable polymers which can be used in different biomaterials applications. General structure–property correlation makes polymers' properties varied in a predictable and systematic fashion. Accelerated hydrolytic degradation studies of polyarylates were performed at 70°C in acid and alkali medium. The degradation rates of polymers were in accordance with their water absorption. The degradation rates of samples in acid medium were lower than those in alkali medium.

Keywords:

• BIODEGRADATION
• L-TYROSINE
• CYCLIC DIPEPTIDE
• POLYARYLATE
• STRUCTURE-PROPERTY CORRELATIONS