Abstract: A composition includes a polyester urethane. The polyester urethane includes a crosslinker based on diisocyanate and an alternating copolymer resin of polyol and polyacid. The resin has a degree of branching, weight average molecular weight, polydispersity index, and viscosity prior to the crosslinking. The polyester urethane has a microstructure of hard segments and soft segments based on a selected combination of polyol, polyacid, degree of branching, the weight average molecular weight, the polydispersity index, the viscosity, the diisocyanate, the first stoichiometric ratio, and the second stoichiometric ratio. The microstructure provides a predetermined property to the composition selected from a degradation rate in an aqueous environment, release rate of a drug loaded in the polyester urethane in the aqueous environment, solubility of the drug, and combinations thereof.