New amino acid based biodegradable poly(ester amide)s via bis-azlactone chemistry

Abstract

Three new classes of the amino acid based biodegradable (AABB) polymers were synthesized via step growth polymerization of bis-azlactones and amino acid based diamine-diesters with activated fatty diester and alkylenediamine: a) poly(ester amide)s (PEAs) were obtained by polymerization of bis-azlactones with diamine-diesters, b) hydrophobically modified co-poly(ester amide)s (co-PEAs) were synthesized by copolymerization of activated fatty diacid diester and bis-azlactones with diamine-diesters, and c) poly(ester amide-co-amide)s (PEA-co-PAs) were obtained by copolymerization of alkylene diamine and diamine-diesters with bis-azlactones. The new poly(ester amide)s showed relatively low-molecular-weights (Mw within 2,800–19,600¿Da, GPC in DMF), whereas the new co-poly(ester amide)s and poly(ester amide-co-amide)s exhibited high-molecular-weights (Mw within 40–100¿kDa) leading to good mechanical properties. Incorporation of the bis-azlactone fragments into the poly(ester amide)s backbone increased hydrophobicity and thermal stability, whereas incorporation of diamine-diester units into the backbone of the bis-azlactone based polyamides rendered them biodegradable. Synthesized AABB polymers are potential candidates for constructing resorbable surgical and pharmaceutical devices.