Enhanced transdermal delivery of a dipeptide by dermaportation

Poor skin permeability and stability limits the application of peptides to the skin. Enhanced skin permeation could offer new therapies for a range of dermatological and cosmetic applications. The aim of this study was to investigate the application of a novel magnetic field enhancement technology to peptide delivery across the skin. Ala-Trp was used as a model dipeptide. Stability of the dipeptide in a range of conditions and with exposure to skin was determined. Dermaportation-magnetic field technology increased the in vitro permeability coefficient of Ala-Trp across human epidermis from 7.7 x 10(-4) cm/h with passive diffusion to 1.94 x 10(-2) cm/h with Dermaportation. Ala-Trp was unstable with exposure to human epidermis. Following permeation across the epidermis, a degradation product was detected in the receptor solution with the amount increasing up to 6 h. Given the susceptibility of peptides to degradation in the skin it is essential that they are delivered rapidly across the skin in order to maximize the opportunity for delivery of the native peptide. Dermaportation offers a potential new delivery method for skin delivery of peptides for a range of dermatological and cosmetic applications. (C) 2008 Wiley Periodicals, Inc.