Anisotropic nanocellulose gel-membranes for drug delivery: Tailoring structure and interface by sequential...

This study investigates periodate-chlorite oxidation as a pretreatment to tailor the surface charge density of cellulose nanofibers employed in open-porous anisotropic hydrogel membranes for transdermal drug delivery. The obtained materials feature high specific surface (≤500 m² g^-1, BET), small average pore size (ca. 40 nm) and tunable surface charge, which are key properties for adsorption and slow release of charged drug molecules. Loading of the non-steroidal anti-inflammatory drug (NSAID) piroxicam (PRX) into the membranes confirmed that the extent of loading is governed by surface charge density and carboxylate group content, respectively, which can be controlled by the oxidation procedure within the range of 0.74-2.00 mmol g^-1. Prolonged release of PRX over several hours was observed upon exposure of the loaded membranes to simulated human skin fluid demonstrating the applicability as drug delivery patches.