Toxicity studies with flutrimazole.

Studies with 1-[(2-fluorophenyl)(4-fluorophenyl)phenylmethyl]-1H- imidazole (flutrimazole, CAS 119006-77-8), a new topical imidazole antifungal agent, have been carried out to investigate the acute toxicity of the active substance in mice and rats, as well as the acute ocular and dermal irritation in rabbits, the dermal tolerance after repeated dose (21 days) applications in rabbits, and the sensitising, photoallergic and phototoxic potential in guinea pigs using 1% flutrimazole cream. LD50 values after oral or intraperitoneal administration were greater than or equal to 1000 mg/kg in both mice and rats, which reveal a very low acute toxicity of flutrimazole. No differences were found between the excipient and 1% flutrimazole cream in the acute ocular and dermal irritation studies in rabbits, the irritation indexes being indicative of no lesions due to flutrimazole. Cumulative dermal irritation studies in rabbits showed an improved local tolerance of a skin cream containing 1% flutrimazole as compared to a commercial skin cream containing 1% clotrimazole. The irritation indexes were 1.2 and 3.7, respectively (p less than 0.01). The corresponding histophatological findings confirmed the better local tolerance of 1% flutrimazole cream. Furthermore, it has been found that flutrimazole cream lacks sensitising potential (Magnusson and Kligman test), is also devoid of phototoxic potential and does not induce photoallergic reactions in guinea pigs, these data being confirmed by histopathological studies. These results, together with the very slight systemic absorption rate of flutrimazole from the 1% topical drug form, clearly show that no restrictions should be taken in the use of the cream for reasons of systemic toxicity or dermal tolerance.