[Fungicidal activity of liranaftate against Trichophyton rubrum]

The fungicidal activities of thiocarbamate antifungal agent liranaftate were studied by determining the MIC and the MCC against Trichophyton rubrum with the Milliflex -100 Test System and by determining the time-kill curve in comparison to that of six reference agents. Liranaftate and lanoconazole both showed excellent fungistatic activity against the conidia of T. rubrum. For each of these agents, the MIC after 14 days of contact was 0.009 g/ml. The liranaftate-induced decrease in the MCC occurred from 9 days onwards; MCC at 14 days was 0.039 g/ml. The MCC for tolciclate was also reduced from 9 days onwards, but that of amorolfine, lanoconazole, neticonazole, clotrimazole and bifonazole was not lowered up to 14 days. Similar results were obtained when the studies were performed with germinated conidia. The time-kill curves showed that both liranaftate and tolciclate, at concentrations ranging from 2 to 32 times the MICs, achieved a decrease in viable counts to below the detection limit within 7 to 9 days. In experiments with low levels of inoculum, only amorolfine produced a decrease to below the detection level, and that occurred at 14 days; no reduction in viable counts was observed up to 14 days with the four azole agents. Our data suggest that antifungal agents of the thiocarbamate class possess the most potent fungicidal activity against dermatophytes; these are followed in order by morpholine and azole antifungals.