Prolonged activity of a recombinant manganese superoxide dismutase through a formulation of polymeric multi-layer nanoassemblies targeting cancer cells.

A new isoform of human manganese superoxide dismutase (SOD) has been recently isolated and obtained in a synthetic recombinant form and termed rMnSOD. As compared to other SODs, this isoform exhibits a dramatically improved cellular uptake and an intense antioxidant and antitumoral activity. Unfortunately, its use is severely hampered as this active pharmaceutical ingredient (API) in solution suffers from remarkable instability, which realizes as an interplay of unfolding and aggregation phenomena. This leads the API to be ineffective after three weeks only when stored at 4°C. A formulation strategy was undertaken to mitigate this instability. This was based on the incorporation of the API in hyaluronic acid and its layer-by-layer deposition over a chitosan-n-acetyl cysteine- monolayer nanoemulsion (NE) and its subsequent coverage with a further external interface of a chitosan-n-acetyl cysteine. The obtained constructs were tested over a selected panel of healthy and cancerous cell lines. The undertaken formulation strategy enhanced the API's effect in vitro already at time zero, maintaining the efficacy of this anticancer agent until up to 30 weeks when stored at 4°C.