Interaction of Stratum Corneum Components With Benzalkonium Chloride. Isothermal titration calorimetric study

The interactions of benzalkonium chloride (BC)with components of stratum corneum, a model system of intercellular lipids in human stratum corneum and homogenized rat stratum corneum were characterized in terms of thermodynamics at pH 7.5 and 37°C. BC was strongly bound to cholesterol and cholesterol sulfate with higher affinities (10⁵~10⁶ M^-1) than to any other components of the stratum corneum by hydrophobic interaction and ionic interaction, respectively. BC binding to the model system of intercellular lipids significantly decreased only in the absence of cholesterol. It is indicated that cholesterol and its derivatives play an important role in the penetration and/or accumulation of BC in stratum corneum. This revised version was published online in July 2006 with corrections to the Cover Date.