The influence of two azones and sebaceous lipids on the lateral organization of lipids isolated from human stratum corneum

The main problem with topical application of compounds to administer drugs to and regulate drug levels in a human body, is the barrier formed by the i ntercellular lipid matrix of the stratum corneum (SC). In a search for poss ibilities to overcome this barrier function, a good understanding of the or ganization and phase behavior of these lipids is required. SC lipid model s tudies especially provide a wealth of information with respect to the lipid organization and the importance of certain subclasses of lipids for the st ructure. Previously, we have shown that electron diffraction (ED) provides detailed information on the lateral lipid packing in both intact SC (G.S.K. Pilgram et al., J. Invest. Dermatol. 113 (1999) 403) and SC lipid models ( G.S.K. Pilgram et al., J. Lipid Res. 39 (1998) 1669). In the present study, we used ED to examine the influence of two atones and sebaceous lipids on the lateral phase behavior of lipids isolated from human SC. We established that human SC lipids are arranged in an orthorhombic packing pattern. Upon mixing with the two enhancers the orthorhombic packing pattern was still o bserved; however, an additional fluid phase became more apparent. In mixtur es with sebaceous lipids, the presence of the hexagonal lattice increased. These findings provide a basis for the mechanism by which these enhancers a nd sebaceous lipids interact with human SC lipids. (C) 2001 Elsevier Scienc e B.V. All rights reserved.