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 concentration s 10 and 20 mM and ultrasonic stimulation was used to induce structural mod ifications in the pig stratum corneum (SC). The composition of the disaggre gated material and the microstructure of the residual tissue after treatmen t were studied. This combined treatment mainly removed proteins and small a mount of lipids. The disaggregated components formed complexes via hydropho bic interactions and covalent bonds. The presence in the disaggregated frac tion of glutamic acid residues covalently linked to ceramides indicated tha t the OG affected the corneocyte envelopes. The correlation between the los s of the tissue cohesion and the disaggregation of the protein components u nderlines the important role played by the corneocyte envelopes in this coh esion. Wide and small angle X-ray diffraction showed that although the trea tment produced a small loss of order in the SC structure arrangement (tissu e disaggregation) the lamellar structure of the intercellular lipids remain ed almost unaffected. This fact sharply contrasts with the fragility of the corneocyte envelopes and the structural proteins against OG. A tissue disa ggregation process in layers is proposed, which occurred by disruption of S C into corneocytes, disaggregation of the corneocyte envelopes and preserva tion of the intercellular lamellar structure. (C) 2000 Elsevier Science B.V . All rights reserved.