Figure 1.

Schematic representation of a (4-AP)-loaded thermogel as a local controlled-release delivery system. (A) Chemical structures of 4-AP and PLGA–PEG, respectively. (B) Amphiphilic polyester–PEG–polyester triblock copolymers self-assemble into micelles in aqueous solution at room temperature and form a solid gel via cross-links at higher temperature. (C) 4-AP can be incorporated into the triblock copolymer at room temperature and injected into an animal in liquid phase. Once the formulation reaches body temperature, it forms an in situ hydrogel for controlled release of 4-AP.