Hybrid Nanostructured Films for Topical Administration of Simvastatin as Coadjuvant Treatment of Melanoma

This work aims at (1) assessing the potential of repurposing simvastatin (SV) to support the most common therapies against melanoma and (2) developing an innovative topical adhesive film, composed by chitosan-coated nanostructured lipid carriers (Ch-NLC) used as drug vehicle. A factorial design approach was employed as the basis for the formulation development. Optimized Ch-NLC displayed a particle size of 108 ± 1 nm, a polydispersity index of 0.226, a zeta potential of 17.0 ± 0.6 mV, as well as an entrapment efficiency of 99.86 ± 0.08%, and SV loading of 14.99 ± 0.01%. The performance of SV-Ch-NLC films was assessed in terms of release, permeation, and adhesion, as critical quality attributes. Cutaneous tolerability and in vitro cytotoxicity studies were performed to warrant film safety and drug effectiveness, respectively. The topical films provided a sustained release kinetic profile of SV and were classified as nonirritant systems. The encapsulation of SV increased cytotoxicity in melanoma cells. The key role of squalene as nanostructuring agent of the lipid nanoparticle matrix and as permeation enhancer was highlighted, suggesting its key action for potentiating skin permeation and uptake into melanoma cells. Topical SV-Ch-NLC films are thus able to provide an in situ extended drug delivery and useful as coadjuvant treatment of melanoma skin lesions.