Controlled Synthesis of Hyperbranched Poly (ester)s From Biorenewable Monomers for the Delivery of Therapeutic Agents

A series of hyperbranched poly(ester)s (HBPEs) has been prepared from renewable bio monomers using the Macosko-Miller conditional probability model (appropriate for monomers containing functional groups of unequal reactivity) to select ratios of reactants (ratios of reactive functional groups) to permit high monomer conversion without gelation and to assure the presence of specific reactive end groups. These materials have been fully characterized using spectroscopic, chromatographic and thermal methods and may serve as excellent platforms for the attachment of various therapeutic agents. Even though the conjugates were not water soluble, release of the active agents from fine suspensions of the conjugates occurred readily by hydrolysis in aqueous media under enzyme-catalyzed hydrolysis. The rate of release of the therapeutic agent from the suspension was found to be zero order (linear with time) and can be tuned by altering the composition of the HBPE.