Intradermal drug delivery: the field of dermatological research by sonophoresis M. Nino, G. Calabrò , A. Patalano and P. Santoianni Dept. of Systematic Pathology - Section of Dermatology - University of Naples Federico II INTRODUCTION The skin is an important barrier to the penetration of exogenous substances and a potential route for the transport of functional active principles. Several methods have been studied to increase the penetration for a systemic or a loco-regional effect. Sonophoresis is the main physical technique that increases cutaneous penetration of substances. It is based on 20 to 25 KHz ultrasounds that can induce alterations of the horny barrier through micromechanical, thermal and cavitation effects. MATERIALS AND METHODS This study evaluated the efficacy of low frequency sonophoresis (LFS) at 25 KHz produced by a sonicator for treatment of alopecia areata, melasma and solar lentigo. 30 patients affected by alopecia areata were treated for a 3-month period by 36 applications (three times a week) of methylprednisolone 0.5% pet. or cyclosporine 0.1% solution followed by LFS. 48 women with melasma and 48 with solar lentigo were treated for a 5-week period by 10 applications (twice a week) with a depigmenting emulsion based on cogic, azelaico and ascorbic acid and LFS application.