Both the formulations developed showed positive profiles in terms of the skin accumulation of CP in vitro. The Na-DOC gel accumulated a much higher drug amount in the skin with respect to a commercial cream used as reference with the same CP concentration (0.05%) . On the other hand, the CP-loaded NP formulation accumulated the same drug amount as the commercial cream, but starting from a ten-fold lower CP concentration, i.e., 0.005% w/w .