The present invention provides bioerodable constructs for controlled release of bioactive materials. In a preferred mode, the constructs may be utilized adjacent to a biological surface. The constructs are based on a blend of two or more poly(ester-amide) polymers (PEA). Such polymers may be prepared by polymerization of a diol (D), a dicarboxylic acid (C) and an alpha-amino acid (A) through ester and amide links in the form (DACA).sub.n. An example of a (DACA).sub.n polymer is shown below in formula II. Suitable amino acids include any natural or synthetic alpha-amino acid, preferably neutral amino acids.