[In vitro antifungal activity of amorolfine, a new morpholine antimycotic agent]

In vitro antifungal activities of amorolfine (MT-861), a newly developed morpholine antimycotic agent, against a wide range of pathogenic fungal strains were investigated using an agar-dilution method with an imidazole antifungal agent, clotrimazole (CTZ), as the reference drug. The results showed that MT-861 had a broad antifungal spectrum, and was active against all of the pathogenic fungi tested except nonpigmented filamentous fungi such as aspergilli and penicillia. Dermatophytes and Malassezia furfur was the most highly susceptible to MT-861. Antifungal activities of MT-861 against most strains of these fungi as well as those against most strains of dimorphic fungi were higher than those of CTZ. By contrast, MT-861 showed lower activities against pathogenic yeasts such as Candida albicans than CTZ. Several assay conditions, such as inoculum size of fungi, incubation time, media pH and compositions including serum supplementation, affected MT-861 activities against C. albicans and, to lesser extents, those against Trichophyton mentagrophytes. MIC values of MT-861 against C. albicans and other Candida spp., were the lowest on casitone agar. MT-861 exerted fungicidal actions toward susceptible fungi such as T. mentagrophytes and Sporothrix schenckii at relatively low concentrations, and these activities were increased when the time of incubation was extended beyond 24 hours after inoculation of testing organisms. Susceptibilities of any strains of C. albicans and C. glabrata to MT-861 were not reduced by as many as 15 successive transfers in MT-861 containing media.