Lateral diffusion of ibuprofen in human skin during permeation studies.

In order to characterize the quality of dermal preparations, permeation studies using human stratum corneum or artificial skin constructs are carried out. For a better understanding of the diffusion processes a method to measure the lateral diffusion in skin samples was developed allowing an estimation of built-up drug depots. By extracting concentric skin segments surrounding the site of application, lateral drug diffusion was determined. Both, excised human skin and artificial skin constructs, showed comparable results with two phases of lateral diffusion (accumulation/redistribution). The use of permeation enhancers promoted lateral diffusion and thus increased the tendency to create a drug depot within the skin.