Effect of SDS concentration in the Coupling Medium on Ultrasound-Induced Changes in Skin Barrier

Low-frequency ultrasound (US) has been shown to increase drug permeation into the skin. Sodium dodecyl sulphate (SDS) is often included in the coupling medium at 1 %w/v. We have shown a highly irregular relationship between the surfactant concentration and protein flux through skin in in vitro experiments (Table 1; Dahlan et al, 2005). The in vitro data suggested that lower SDS concentrations might induce similar protein permeation into the skin; lower SDS levels are expected to cause less skin irritancy. We, therefore, studied the effects of SDS concentration on US-induced changes in skin barrier properties in vivo, in mice and rats.