Doubly Hydrophilic Multiarm Hyperbranched Polymers with Acylhydrazone Linkages as Acid-Sensitive Drug Carriers

A novel type of drug carrier capable of controlled drug release is proposed. It consists of an acid-sensitive doubly hydrophilic multiarm hyperbranched copolymer with a hyperbranched polyamidoamine core and many linear poly(ethylene glycol) arms. Using pH-sensitive acyl-hydrazone linkages, the polymer forms unimolecular micelles that can encapsulate hydrophobic drugs. Due to their amphiphilicity, the drug-loaded unimolecular micelles can self-assemble into multi-molecular micelles that show acid-triggered intracellular delivery of the hydrophobic drugs.