Objective: To establish a new model to evaluate the antifungal activity of antimycotics.
Methods: Twenty-one healthy adult volunteers without clinically significant differences in demographic characteristics, hydration status of the skin, and sebum excretion were randomly divided into two groups: group 1 receiving 200 mg itraconazole bid for 1 week, and group 2 receiving itraconazole 200 mg qd for 1 weeks. Stratum corneum stripping was taken from the forearm skin at days 0, 1, 4, 7, 10, 14, 21, 28, and 35. Spores of selected fungi (Trichophyton rubrum, Trichophyton mentagrophytes, and Microsporum canis) were deposited and cultured on the center of the stratum corneum stripping. After 1-week culture the stratum corneum stripping was staining by PAS, and the area covered by dermatophyte was measured by corneofungimetry and computerized-assisted image analysis so as to calculate the inhibitory effect of the oral antifungal agents administered.
Results: All three dermatophytes grew on the stratum corneum stripping, the area covered by the dermatophyte was dense before administration of antifungal agent, and decreased gradually after the administration of drug, and to the least on the seventh day (P < 0.01), however, the area covered by the dermatophyte began to increase since the tenth day, and reach the biggest on the thirty-fifth day. Itraconazole at two different dosages showed significant activity against these 3 dermatophytes without significant difference between the two groups (all P > 0.05).
Conclusion: The ex vivo growth environment of dermatophyte on human stratum corneum is very similar to that of human milieu interne. Itraconazole displays a high antidermatophyte activity in human stratum corneum. Corneofungimetric bioassay is a new method between in vitro trial and in vivo effect.