In vivo fungicidal effect of KP-103 in a guinea pig model of interdigital tinea pedis determined by using a new method for removing the antimycotic carryover effect

We developed a new technique for culture study that successfully recovers fungi from drug-treated skin tissues, in which tissue specimens were homogenized, dialyzed against water, digested with trypsin, and then washed with PBS, to eliminate the drug that remaining in the skin tissue specimens. With this modified culture method, we reevaluated the efficacy of KP-103, neticonazole, and lanoconazole in a guinea pig interdigital tinea pedis model. Guinea pigs with tinea pedis were topically treated with a 1% solution of KP-103 or a reference drug once a day for 10 consecutive days. Five days after the last treatment, left and right feet were subjected to culture study by the conventional and modified recovery culture methods, respectively. One hundred percent (20/20) of lanoconazole-treated feet were judged as culture-negative by the conventional culture method, but 85% (17/20) of the feet were shown to be culture-positive when the modified recovery culture method was used. On the other hand, KP-103 achieved high rates of culture-negative rates, 95% (19/20) and 85% (17/20), in both conventional and modified culture methods, respectively. Furthermore, on day-30 posttreatment, KP-103 sterilized 14 of the 20 infected feet, whereas neticonazole and lanoconazole were not effective even in reducing fungal burden. KP-103 proved to be highly effective in achieving mycological cure and preventing relapse against tinea pedis presumably because of its good bioavailability in the skin based on its low keratin-affinity, along with its potent antifungal activity.     

KP-103, a novel triazole derivative,is effective in preventing relapse and successfully treating experimental interdigital tinea pedis and tinea corporis in guinea pigs

The therapeutic efficacy of KP-103, a triazole derivative, for 10 guinea pigs with interdigital tinea pedis or tinea corporis was investigated. Topical KP-103 solution (0.25 to 1%) was dose-dependently effective in treating both dermatophytoses. A 1% KP-103-treatment rendered all infected skins culture-negative on day-2 posttreatment. A high negative-culture rate was obtained with 1% solutions of butenafine and lanoconazole but not with 1% neticonazole solution. The follow up study performed on day-30 and day-9 posttreatment demonstrated that the relapse rates for 1% KP-103-treated animals with tinea pedis and for those with tinea corporis were 20 and 30%, respectively, and that these values were the same as those for 1% butenafine-treated animals, but lower than those for 1% lanoconazole-treated animals (55 and 80%, respectively). When a single dose of 1% KP-103 was applied to the back skin 48 hr before fungal inoculation, 9 of the 10 animals were protected from the dermatophytosis, suggesting that active KP-103 is retained in skin tissue for at least 48 hr after dosing. Moreover, it was suggested that KP-103 retains a high activity in the horny layer because of its lower keratin-affinity. The effectiveness of KP-103 against dermatophytoses may be due to the favorable pharmacokinetic properties in the skin tissues, together with its potent antifungal activity.     

新型酮康唑喷膜对豚鼠体癣模型疗效的观察

目的 观察新型酮康唑喷膜对豚鼠体癣模型的疗效。方法 选择健康豚鼠20只,用穿刺法制备豚鼠体癣模型。将体癣模型随机分A组（新型酮康唑喷膜治疗组）,B组（喷膜基质治疗组）,C组（复方酮康唑霜治疗组）和D组（对照组）。根据豚鼠皮疹和真菌学检查进行疗效评估。结果 A组和C组的豚鼠治疗后局部红斑和水肿明显减轻,与治疗前比较有显著意义（P〈0．05）;停药2周时,A组和C组真菌镜检、培养阴性率均为100％,明显高于B和D组（P〈0．05）。结论 新型酮康唑喷膜对豚鼠体癣模型有良好的抗真菌活性。     

Anti-dermatophytic activity of bakuchiol: In vitro mechanistic studies and in vivo tinea pedis-inhibiting activity in a guinea pig model

Bakuchiol was an active antifungal compound isolated from Psoraleae Fructus by means of bioassay-guided fractionation in our previous study. The present work aimed to investigate the underlying mechanisms and the therapeutic effect of bakuchiol in Trichophyton mentagrophytes-induced tinea pedis. After exposure to bakuchiol at 0.25-fold, 0.5-fold and 1-fold of minimum inhibitory concentration (MIC) (3.91 μg/ml) for 24 h, the fungal conidia of T. mentagrophytes demonstrated a significant dose-dependent increase in membrane permeability. Moreover, bakuchiol at 1-fold MIC elicited a 187% elevation in reactive oxygen species (ROS) level in fungal cells after a 3-h incubation. However, bakuchiol did not induce DNA fragmentation. In a guinea pig model of tinea pedis, bakuchiol at 1%, 5% or 10% (w/w) concentration in aqueous cream could significantly reduce the fungal burden of infected feet (p < 0.01–0.05). In conclusion, this is the first report to demonstrate that bakuchiol is effective in relieving tinea pedis and in inhibiting the growth of the dermatophyte T. mentagrophytes by increasing fungal membrane permeability and ROS generation, but not via induction of DNA fragmentation.