Amino Acid Based Epoxy-Poly(Ester Amide)s—A New Class of Functional Biodegradable Polymers: Synthesis and Chemical Transformations

Abstract

A new class of biodegradable functional polymers – epoxy-poly(ester amide)s (EPEAs), was synthesized for the first time on the basis of naturally occurring α-amino acids, fatty diols and cis- and trans-epoxysuccinic acids. The syntheses were conducted via both solution Active Polycondensation and Interfacial Polycondensation using, accordingly, either activated di-p-nitrophenyl esters or dichlorides of cis- and trans-epoxysuccinic acids as bis-electrophilic monomers. Di-p-toluenesulfonic acid salts of bis-(L-phenylalanine)-1,6-hexylene and bis-(L-leucine)-1,6-hexylene diesters were used in both cases as bis-nucleophilic counter-partners. High-molecular-weight polymers (M_w up to 67.000) with desirable material properties were obtained via solution polycondensation using di-p-nitrophenyl-trans-epoxy succinate. The EPEAs were chemically modified further under mild conditions: oxirane groups along the backbone were reacted with both nucleophilic and electrophilic reagents, and also subjected to thermal and chemical curing. The macromolecular transformations of EPEAs substantially broaden material properties and, hence, the potential to apply amino acid-based biodegradable poly(ester amide)s as absorbable drug carriers and surgical devices.

Keywords:

• α-amino acids
• epoxysuccinic acid
• biodegradable polymers
• synthesis of epoxy-poly(ester amide)s
• functionalization of polymers

Acknowledgments

This study was funded in part by grant no. G-802 from the International Science and Technology Center (ISTC). The authors thank Professor M. Okada (Chubu University, Japan) for supporting this work, Dr. H. Panosyan (Molecule Structure Research Center, National Academy of Sciences of Armenia) for the NMR study and Ms. P. Toidze (Georgian Technical University) for the GPC measurements used.