Synthesis and characterization of functional elastomeric poly(ester amide) co-polymers

A new family of random co-poly(ester amides)s (co-PEAs) having reactive pendant functional carboxylic acid groups were synthesized by co-polycondensation of di-p-toluenesulfonic acid salts of bis-(L-alpha-amino acid (L-leucine and/or L-phenylalanine)) alpha,omega-alkylene diesters with active diesters of dicarboxylic acids using di-p-toluenesulfonic acid salt of L-lysine benzyl ester as a co-monomer. The lateral benzyl ester groups in the L-lysine segment of co-PEAs were subsequently transformed into free COOH groups by catalytic hydrogenolysis using Pd black as a catalyst. The co-PEA-based polyacids obtained, as well as the original co-PEA having lateral benzyl ester groups were characterized by standard methods. In vitro biodegradation studies in the presence of hydrolases like alpha-chymotrypsin and lipase showed significant enzymatic-catalyzed biodegradation of these co-PEAs. These co-PEA-based polyacids were used for covalent attachment of iminoxyl radicals (4-amino-TEMPO) and in vitro biodegradation of 4-aminoTEMPO attached polymer was studied along with releasing kinetic of iminoxyl radical.