Antifungal properties of a novel 1,2,4-triazine derivative I 319.

The antifungal activity of the sodium salts, of 3-thiolo-5-phenyl-1,2,4-triazine (I 319) was determined in vitro and in vivo. The minimal inhibitory concentration (MIC) of I 319 for 33 pathogenic and saprophytic fungal strains ranged from 3.1 to 25 microgram/ml. In vivo, experiments were performed on a model of subacute candidiasis in Balb/c mice infected intraperitoneally with Candida albicans. The antifungal activity was estimated on the basis of the extension of the mice life span and on the number of living yeast cells present in the kidneys, liver and spleen of treated and control mice. A single i.p. dose of I 319 (25 mg/kg) prolonged the survival time of treated animals up to 200%. Five subsequent doses of the compound diminished the number of C. albicans cells in the tissues of these mice. The DL50 of I 319 for mice (i.p.) was about 250 mg/kg.