A COMPARISON OF THE EFFECTS OF ELECTRICAL-CURRENT AND PENETRATION ENHANCERS ON THE PROPERTIES OF HUMAN SKIN USING SPECTROSCOPIC (FTIR) AND CALORIMETRIC (DSC) METHODS

Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and differential scanning calorimetry (DSC) studies were undertaken to compare the effects of iontophoresis with those of penetration enhancers on the structural properties of the human stratum corneum. These investigations clearly show the combined ability of these two techniques to detect changes in the lipids and proteins of the skin. Our spectroscopic results confirm that treatment with DMSO causes extensive lipid extraction as investigations with a range of other techniques had previously suggested. In addition, the DSC results indicate that DMSO causes stratum corneum protein denaturation. Interestingly, cineole also caused extensive lipid extraction, thus suggesting that lipid. extraction may play a role in the transdermal penetration enhancing effect of cineole. Oleic acid/ethanol treatment not only caused an increase in the average lipid acyl chain disorder of treated samples but also led to extensive lipid extraction. In contrast, when ATR-FTIR spectroscopy and DSC were used to evaluate the effect of electrical treatment on the stratum corneum, minimal change was observed on the lipid-cellular matrix; it would appear that electrical treatment exerts a less disruptive influence on the stratum corneum than treatment with penetration enhancers.