Novel fast degradable thermosensitive polymeric micelles based on PEG-block-poly(N-(2-hydroxyethyl)methacrylamide-oligolactates)

The aim of this study was to design a thermosensitive polymeric micelle system with a relatively fast degradation time of around 1 day. These micelles are of interest for the (targeted) delivery of biologically active molecules. Therefore, N-(2-hydroxyethyl)methacrylamide-oligolactates (HEMAm−Lacn) were synthesized and used as building blocks for biodegradable (block co) polymers. p(HEMAm−Lac2) is a thermosensitive polymer with a cloud point (CP) of 22 °C which could be lowered by copolymerization with HEMAm−Lac4. The block copolymer PEG-b-((80%HEMAm−Lac2)−(20%HEMAm−Lac4)) self-assembled into compact spherical micelles with an average size of 80 nm above the CP of the thermosensitive block (6 °C). Under physiological conditions (pH 7.4; 37 °C), the micelles started to swell after 4 h and were fully destabilized within 8 h due to hydrolysis of the lactate side chains. Rapidly degrading thermosensitive polymeric micelles based on PEG-b-((80%HEMAm−Lac2)−(20%HEMAm−Lac4)) have attractive features as a (targete...