Maleimide-bearing nanogels as novel mucoadhesive materials for drug delivery

Novel maleimide-functionalised nanogels have been synthesised via the polymerisation of 2,5-dimethylfuran-protected 3-maleimidoethyl butylacrylate in the presence of presynthesised poly(N-vinylpyrrolidone) (PVP) nanogel scaffolds using surfactant-free emulsion polymerisation techniques. The protected maleimide nanogels were subsequently deprotected to generate the reactive maleimide group via a retro-Diels-Alder reaction. These activated nanogels were found to exhibit excellent mucoadhesive properties on ex vivo conjunctival tissue when compared to the known mucoadhesive chitosan. In order to determine the viability of the materials as drug carriers, nanogels were loaded with a model drug compound and the in vitro release kinetics were analysed. The nanogels could sustain the release of a model drug compound over several hours owing to the swellable hydrophilic nanogel structure, exhibiting first order release kinetics. As a consequence, these findings support the potential of these maleimide-bearing nanogels as a novel platform for sustained drug delivery.