Studies were conducted to assess the penetration of 1 % ciclopiroxolamine cream, establishing the concentrations of the antimycotic compound in different layers of the stratum corneum with two skin models. Results of in vitro studies using skin from domestic pigs indicate that ciclopiroxolamine has the ability to penetrate fast into the epidermis, by inhibiting and killing inoculated Trichophyton mentagrophytes. In vivo investigation of the stratum corneum has been performed in healthy human volunteers by 20 strippings collected in four layers. Fungicidal concentrations of ciclopiroxolamine were determined after extraction from the strippings. These studies demonstrate that the concentrations reached levels which are sufficient to inhibit and kill pathogenic fungi.

This report presents original methods to assess the bioavailability of an antifungal drug from a varnish preparation in finger nails. For the studies with human volunteers a ciclopirox 8 % nail lacquer was used to determine its efficacy in the treatment of onychomycoses. In vivo studies were performed on the fingernails of healthy volunteers by determining the total amount of ciclopirox penetrated per milligram of nail and the partition of the drug in the plate of the nails (technically divided into four layers). Ciclopirox concentrations were evaluated by measuring the inhibition of Candida pseudotropicalis growth in vitro. The ciclopirox concentration after 30 days treatment was determined as 3.35 ± 0.82 µg/mg nail material. This is a sufficient amount to kill the fungal pathogens. In addition, in vitro penetration experiments were carried out with excised pig skin. Lacquer formulations from 0.5 to 8 % were used to inhibit the growth of Trichophyton mentagrophytes. Formulations from 2 to 8% led to a strong to total inhibition of the dermatophyte after 30 min treatment time.