Iontophoretic Application of Terbinafine Gel to the Large Toe Nail

Terbinafine is recognized as one of the most effective drugs for the treatment of toe nail fungus (onychomycosis). This trial will be the first test of a new device to improve the delivery of terbinafine directly to the toe nail. The device uses a low level of electric current, iontophoresis, to "push" the terbinafine into the nail. The study will involve a single application of terbinafine, in a gel form, with the iontophoretic device. The treatment will be applied to the surface of both large toenails of healthy subjects. Subjects will be asked to report any sensations in the nail or surrounding skin experienced during or after treatment. Samples from the edge of the treated toe nail will be taken at 2-4 week intervals to measure how much terbinafine was delivered to the nails, and blood samples will be taken for the first 24 hours after treatment to determine how much, if any, terbinafine was absorbed into the subjects's body. Observations will also be made of the treated toes to look for any irritation of the surrounding skin due to the treatment.