Use of wide and small angle X-ray diffraction to study the modifications in the stratum corneum induced by octyl glucoside

The combined action of the octyl glucoside (OG) surfactant at concentrations 10 and 20 mM and ultrasonic stimulation was used to induce structural modifications in the pig stratum corneum (SC). The composition of the disaggregated material and the microstructure of the residual tissue after treatment were studied. This combined treatment mainly removed proteins and small amount of lipids. The disaggregated components formed complexes via hydrophobic interactions and covalent bonds. The presence in the disaggregated fraction of glutamic acid residues covalently linked to ceramides indicated that the OG affected the corneocyte envelopes. The correlation between the loss of the tissue cohesion and the disaggregation of the protein components underlines the important role played by the corneocyte envelopes in this cohesion. Wide and small angle X-ray diffraction showed that although the treatment produced a small loss of order in the SC structure arrangement (tissue disaggregation) the lamellar structure of the intercellular lipids remained almost unaffected. This fact sharply contrasts with the fragility of the corneocyte envelopes and the structural proteins against OG. A tissue disaggregation process in layers is proposed, which occurred by disruption of SC into corneocytes, disaggregation of the corneocyte envelopes and preservation of the intercellular lamellar structure.