The in vitro activity of terconazole against yeasts: its topical long-acting therapeutic efficacy in experimental vaginal candidiasis in rats

The activity of the broad-spectrum triazole Antifungal terconazole was evaluated in vitro by the serial decimal dilution technique in broth media. The best correlation between in vitro and in vivo activity was found in brain-heart infusion broth and Eagle's minimum essential medium. All strains of Candida albicans, C. tropicalis, C. krusei, C. parapsilosis, C. guilliermondii, C. glabrata, and Trichosporon beigelii tested were susceptible. Terconazole blocked the morphogenetic transformation from the yeast into the filamentous form at concentrations of 0.008 to 0.05 microgram/ml. In experimental candidiasis in castrated rats with estrogen-induced permanent pseudoestrus, topical treatment with terconazole was superior to miconazole, clotrimazole, econazole, butoconazole, tioconazole, sulconazole, bifonazole, valconazole, fenticonazole, nystatin, and amphotericin B in the various schedules used. A 3-day once-daily intravaginal application of terconazole 0.8% was usually sufficient to provide a functional therapeutic period of 7 days because of prolonged high biologically active Antifungal levels in the vagina. No side effects were observed at any concentration of terconazole.