poly(alpha,beta-(N-2-hydroxyethyl-DL-aspartamide))-poly(alpha,beta-(N-2-thioethyl-DL-aspartamide)) copolymer
poly(alpha,beta-(n-2-hydroxyethyl-dl-aspartamide))-poly(alpha,beta-(n-2-thioethyl-dl-aspartamide)) copolymer