Human skin penetration of a copper tripeptide in vitro as a function of skin layer

Objective and design Skin retention and penetration by copper applied as glycyl-L-histidyl-L-lysine cuprate diacetate was evaluated in vitro in order to assess its potential for its transdermal delivery as an anti-inflammatory agent. Materials and methods Flow-through diffusion cells with 1 cm(2) exposure area were used under infinite dose conditions. 0.68% aq. copper tripeptide as permeant was applied on isolated stratum corneum, heat-separated epidermis and dermatomed skin and receptor fluid collected over 48 h in 4 h intervals using inductively coupled plasma mass spectrometry to analyze for copper in tissues and receptor fluid. Results The permeability coefficient of the compound through dermatomed skin was 2.43 +/- 0.51 x 10(-4) cm/h; 136.2 +/- 17.5 mu g/cm(2) copper permeated 1 cm(2) of that tissue over 48 h, while 97 +/- 6.6 mu g/cm(2) were retained as depot. Conclusions Copper as tripeptide was delivered in potentially therapeutically effective amounts for inflammatory disease.