The increase in paw thickness was significantly lower (p < 0.05) than for the control group at all time points for each and every formulation tested. However, while the commercial formulation and Na-DOC gel had similar efficacy, the NP formulation performed significantly (p < 0.05) better at the third and fourth hour. It is worth mentioning that this higher activity is obtained despite a 10-fold lower drug concentration in the nanoparticle-containing formulation, supporting the evidence that the formulation is more relevant than the drug concentration in the process of CP absorption .