Polyurethane-based supramolecular hydrogels as drug delivery platforms of hydrophobic drugs

In this work, supramolecular (SM) hydrogels based on polyurethanes (PUs) and cyclodextrins (CDs) were designed for advanced drug delivery applications. These systems exhibit hierarchically self-assembled structures consisting in water suspended channel-type crystals given by poly(pseudo)rotaxanes. Indeed, in aqueous solutions PUs containing poly(ethylene oxide) (PEO) domains can interact with CDs, which can thread along PU chains and form poly(pseudo)rotaxanes. These structures can then assemble in physical crystals and induce a sol-to-gel transition, thus forming supramolecular hydrogels. In these systems, free CDs can be exploited to encapsulate and release hydrophobic drugs with anti-inflammatory or anti-bacterial properties.