Treatment of keloid and hypertrophic scars by iontophoretic transdermal delivery of tranilast.

The feasibility of iontophoretic transdermal delivery of tranilast (N-(3,4-dimethoxycinnamoyl) anthranilic acid) for the treatment of keloid and hypertrophic scars was evaluated in hairless rats and humans. A drug electrode containing tranilast 1.5 ml (8 mg/ml in ethanol/water (8/2, v/v) mixture) was placed on the dorsal skin surface of anaesthetised rats or the affected parts of patients, and connected to the negative pole; an electric current (0.5-4 mA for rats, 2 mA for people) was pulsed through at one minute intervals. Tranilast was effectively delivered transdermally iontophoretically into the restricted skin tissues of hairless rats and the affected parts of four patients with hypertrophic scars with no skin damage. In four other patients tranilast given iontophoretically for a period of 30 minutes a week reduced the patients' complaints of pain and itching after only one or two treatments although there were some variations among patients. These results indicate that the transdermal iontophoretic delivery of tranilast is a useful treatment for keloid and hypertrophic scars, particularly for relieving pain and itching, and is more beneficial than tranilast given orally.