Synthesis of Functionalized Poly(caprolactone)s and Their Application as Micellar Drug Delivery Systems

An overview of the recent advances of functionalized poly(caprolactone)s (PCL) and their role in micellar drug delivery systems is presented. Various strategies for the functionalization of ε-caprolactone (εCL) and poly(caprolactone)s are discussed together with the approaches for the engineering of PCL-based micellar assemblies. Hydrophilic moieties, halogens, amines, and unsaturated functional groups have been conjugated to PCL by post-polymerization chemical modification. These pendant functional groups were further modified by deprotection, elimination, 1,3-Huisgen cycloaddition, or cross-linking reactions. Alternately, the anionic activation of PCL enabled the post-polymerization grafting of functional groups onto the polyester backbone. Furthermore, special attention has been given to the engineering of micellar cores to enhance their stability and interaction with encapsulated or covalently conjugated drug molecules. The engineering of the micelle hydrophilic block was also explored to achieve active targeting and enhanced cellular uptake. A combination of these strategies enabled the fine-tuning of functionalized PCL copolymers to generate micelles with properties conducive to drug delivery applications. Functionalized PCL represent a promising direction in the development of tunable micellar drug delivery systems.