Thermo-sensitive polymeric micelles based on poly(N-isopropylacrylamide) as drug carriers

Amphiphilic copolymers are well developed as precursors for the preparation of micellar drug carriers. Poly(N-isopropylacrylamide) (PNIPAAm) is one of the most extensively studied thermo-sensitive polymers that exhibits a lower critical solution temperature (LCST) at around 33 °C in aqueous solution. Over the past decade, considerable efforts have been devoted to design and preparation of PNIPAAm-based thermo-sensitive polymeric micelles as delivery vehicles for controlled drug release. Present review highlights the recent developments in this field, and focuses on two categories of PNIPAAm-based copolymer micelles as smart drug delivery systems, i.e. micelles with PNIPAAm as hydrophilic shell-forming segments below the LCST and micelles with PNIPAAm as hydrophobic core-forming segments above the LCST.