Antifungal activity of GBR-14206, a new imidazole derivative: In vitro studies.: In Vitro Studies

The antifungal activity of GBR-14206, a new imidazole derivative, was evaluated in comparison with those of clotrimazole (CTZ) and miconazole (MCZ) using an agar dilution procedure.GBR-14206 showed a potent activity against a wide range of pathogenic fungi including those associated with deep-seated and subcutaneous mycosis; it inhibited some standard strains of C. albicans at concentrations of 12.5μg/ml or less. Similarly, clinical isolates from various mycoses were also highly susceptible to GBR-14206 (MIC range; 0.0125-6.25μg/ml). The most striking activity of GBR-14206 was displayed against Cryptococcus neoformans (MIC range; 0.0125-0.05μg/ml), which was far superior to MCZ and CTZ. Against C. albicans, Trichophyton spp., and Microsporum spp., the activity of GBR-14206 was more moderate than MCZ and CTZ. Against Sporothrix schenckii, GBR-14206 had a lower mean MIC value than that of CTZ and was similar to MCZ. On the other hand, against Aspergillus spp., GBR-14206 was less effective than MCZ and CTZ. Fungal susceptibility of GBR-14206 tended to be enhanced with increasing medium pH. The activity was also lowered by addition of calf serum.