Thermal and spectroscopic characterization of interactions between 2-nonyl-1,3-dioxolane and stratum corneum components

The effect of 2-nonyl-1,3-dioxolane (SEPA(TM)) on the structure of human st ratum corneum was investigated by FT-IR spectroscopy at variable temperatur e, differential scanning calorimetry and scanning electron microscopy. A si gnificant influence of SEPA(TM) treatment on position and intensity of IR a bsorption bands and DSC thermal transitions of SC lipids was detected. An a ppreciable loosening of SC cell packing was also observed by SEM analysis. These modifications are reversed after SEPA(TM) is removed from the site of application. The results clearly demonstrate that SEPA(TM) is able to modi fy the structure of the lipid matrix in which corneocytes are embedded, thu s suggesting a possible use of SEPA(TM) to increase the permeability of the stratum corneum to lipophilic drugs.