A smart drug delivery system from charge-conversion polymer-drug conjugate for enhancing tumor therapy and tunable drug release

Abstract

A smart drug delivery system is prepared by citraconylated polyaspartic acid (PASP) derivate-drug conjugate. The conjugate contains two pH-sensitive groups: citraconic amide and hydrazone linker. Citraconic amide group can enhance tumor therapy efficiency by the extracellular pH-sensitive charge-conversion property. Hydrazone linker between polymer and drug can cleave efficiently in the intracellular pH environment. The resulting conjugate shows dual-pH sensitive properties: extracellular pH-triggered enhanced tumor targeting and intracellular pH-triggered drug release. The results of physicochemical properties, intracellular location, and cytotoxicity of conjugate micelles demonstrate that this novel smart drug delivery system can enhance intracellular delivery of drug at a low pH and then release drug rapidly.

Keywords: amphiphiles; biomaterials; charge transfer; conjugated polymers; drug delivery systems.