In vitro evaluation of the effect of electrotreatment on skin permeability.

Background: Stratum corneum composition and structure limit cutaneous bioavailability of pharmaceutical and cosmetical agents. Electrically assisted transport can increase the rate and extent of delivery; moreover, it also enables the administration of polar and charged molecules into the skin.
Aims: The objective of this study was to investigate the effect of electrotreatment on skin permeability by measuring the cumulative delivery of caffeine and sodium ascorbyl phosphate. Furthermore, confocal microscopy was used to visualize the effect of electrotreatment on the penetration of calcein.
Methods: Porcine ear skin was used for the in vitro permeation studies, which involved application of either the caffeine or sodium ascorbyl phosphate (NAP) containing gels using the roll-on supplied with the electrotreatment device.
Results: Electrotreatment increased the amount of caffeine and NAP in the skin. Enhancement factors (EF) for NAP of 7.2 and 14.9 were observed following 20 min of electrotreatment and either immediate sampling or a further 60 min of passive diffusion compared with passive diffusion for either 20 or 80 min. The effect on caffeine permeation was less significant (EF = 2.1 for 20 min electrotreatment compared with passive diffusion for 20 min). The confocal microscopy images showed that electrotreatment significantly increased calcein permeation; fluorescence was observed deep into the viable epidermis-reaching depths of up to 60 to 80 microns.
Conclusions: We have shown that electrotreatment increases skin permeability and the cumulative delivery of cosmeticals into the skin.