Intradermal drug delivery: the field of dermatological research by sonophoresis

M. Nino, G. Calabrò , A. Patalano and P. SantoianniDept. of Systematic Pathology - Section of Dermatology - University of Naples Federico II

INTRODUCTIONThe 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 METHODSThis 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.

RESULTSFor alopecia areata the results were: a) with methylprednisolone, 57% partial and 29% total regrowth (Figg. 1-3); b) with cyclosporine, 33% partial and 34% total regrowth (Figg. 4-6). For melasma: 25% partial and 75% complete depigmentation (Figg. 7-8).For solar lentigo: 57% partial and 43% total regression (Figg. 9-10).

CONCLUSIONSThe study shows that LFS is a not aggressive technique, enhances penetration of topic agents obtaining effects at the level of the epidermis, dermis and appendages (intradermal delivery), giving good results in the treatment of some cosmetic skin disorders.

Figg. 4,5,6: Treatment by cyclosporine + LFS: results in a patient. Before treatment (a), after 1-month treatment (b), after 3-month treatment (c).

ba c

Figg. 1,2,3: Treatment by methylprednisolone + LFS: results in a patient. Before treatment (a), after 2-month treatment (b), after 3-month treatment (c).

Alopecia areata

a b c

Melasma

Figg.7-8: Treatment by emulsion + LFS: results in a patient with melasma. Before treatment and after 5-week treatment.

Solar lentigo

Figg. 9-10: Treatment by emulsion + LFS: results in a patient with solar lentigo. Before treatment and after 5-week treatment.