Local and systemic tolerance of flutrimazole skin creams following single and repeated topical application in healthy volunteers.
A double-blind, randomized phase I study was performed in 21 healthy volunteers to evaluate the dermal tolerance of skin creams containing 1% and 2% 1-[(2-fluorophenyl)(4-fluorophenyl)phenylmethyl]-1H-imidazole (flutrimazole, UR-4056, CAS 119006-77-8) or only the excipient, versus a commercial skin cream containing 1% clotrimazole. The study was carried out using the patch-test procedure performed in three stages: 1. single application in the back skin; 2. induction period (usage test) using three skin areas on the volar side of the forearm of each subject, where skin cream samples were applied once a day for a period of three weeks; and 3. after a wash-out period of two weeks, challenge applications in the back and forearm skin. The systemic tolerance of the formulations was also tested. There was no evidence of allergic sensitization after the application of flutrimazole creams, or their excipients, with signs of mild and doubtful skin reactions being observed in few subjects with all formulations. Furthermore, no systemic side effects after topical administration were detected throughout the study.