In vitro studies with R 51,211 (itraconazole).

Area of Science:

• Mycology
• Infectious Diseases
• Pharmacology

Background:

• Antifungal resistance is a growing concern, necessitating the development of new therapeutic agents.
• Azole antifungals are a cornerstone of treatment for many fungal infections.
• Comparative studies are crucial to evaluate the efficacy of novel antifungals against existing treatments.

Purpose of the Study:

• To compare the in vitro antifungal activity of R 51,211 (itraconazole) with ketoconazole, BAY n 7133, and Ro 14-4767/002.
• To assess the efficacy of these agents against a broad spectrum of pathogenic fungi.
• To identify potential advantages of itraconazole in treating specific fungal infections.

Main Methods:

• An agar dilution method (Kimmig agar) was employed to test 148 fungal isolates.
• Incubation was performed at 30°C for 48 hours to 7 days.
• Standardized solutions of each antifungal agent were prepared for testing.

Main Results:

• R 51,211 and Ro 14-4767/002 exhibited the highest activity against Histoplasma capsulatum.
• Itraconazole demonstrated superior in vitro activity against Blastomyces dermatitidis and Cryptococcus neoformans.
• Ro 14-4767/002 was most effective against dermatophytes, followed by R 51,211, ketoconazole, and BAY n 7133.
• R 51,211 showed the best activity against Aspergillus fumigatus, Aspergillus flavus, and dematiaceous fungi.
• All tested azoles had limited activity against zygomycetous fungi, with 90% MICs ≥ 16 µg/ml.

Conclusions:

• Itraconazole (R 51,211) is a promising new orally active triazole with broad-spectrum in vitro antifungal activity.
• Its efficacy against key pathogenic fungi like Cryptococcus neoformans and Aspergillus species warrants further clinical investigation.
• The study highlights the differential activity of azoles against various fungal pathogens, informing treatment choices.