Poly(N-methacryloyl glycine)/nanocellulose composites as pH-sensitive systems for controlled release of diclofenac

The present study reports the development of non-cytotoxic and pH-sensitive nanostructured membranes consisting of a polymer with amino acid pending moieties and bacterial nanocellulose (BC). The nanocomposites were prepared through a simple methodology under green reaction conditions. The obtained materials display good thermal stability (up to 200°C), viscoelastic (storage modulus>700MPa) and mechanical (Young's modulus=3.5-4.9GPa) properties, together with high water uptake capacity. The results of the in vitro MTT assay showed that the nanocomposites are non-cytotoxic to HaCaT cells for 72h. The in vitro release profile of diclofenac sodium salt (DCF) from the nanocomposites into simulated body fluids at different pH values demonstrates the pH-responsive behaviour of these materials. Besides, DCF is mainly retained in the nanocomposites at pH 2.1 and released at pH 7.4, revealing their potential for the controlled release of DCF in dermal as well as in oral drug delivery applications.