152. VISUALIZATION OF IONTOPHORETIC TRANSPORT PATHS IN CULTURED AND ANIMAL SKIN MODELS.

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Lee*, R.D., White*, H.S., Scott^†, E.R. *Department of Chemistry, University of Utah, Salt Lake City, UT, ^†Alza Corporation 8295 Central Avenue NE, Spring Lake Park, MN J. Pharmaceutical Sciences, 85 (11), 1186, American Chemical Society and American Pharmaceutical Association (1996).

Summary: Physiological structures associated with iontophoretic paths in hairless mouse skin and two cultured skin models (“EpiDerm” by Mattek, Corp., and “SKIN” by Advanced Tissue Sciences, Inc.) are reported. Visualization of ionic paths at current densities between 20 and 100 uA/cm² is accomplished by the counterdirectional transport of Fe(CN)₆^4- and Fe³⁺, resulting in the controlled precipitation of colloidal Prussian blue, Fe₄[Fe(CN)₆]₃, at sites of high ionic conductivity. Examination of the Fe₄[Fe(CN)₆]₃-stained tissues using optical microscopy allows unequivocal assignment of iontophoretic paths to physiological structures in the stratum corneum. Deposition of Fe₄[Fe(CN)₆]₃ occurs exclusively at hair follicles in hairless mouse skin, indicating that these appendages provide highly conductive porous paths during iontophoresis. In contrast, the counterdirectional transport of Fe(CN)₆^4- and Fe³⁺ across cultured skin models, which lack appendages, results in the deposition of Fe₄[Fe(CN)₆]₃ along the boundaries of corneocytes. This observation suggests that paracellular iontophoretic transport through lipid bilayer regions is the predominant transport path in the absence of low-resistance pores.

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EpiDerm Data Sheet

EpiDerm Specifications

EpiDerm Technical References

Percutaneous Absorption (EpiDerm Application)

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Applications: Percutaneous absorption/penetration, Transdermal permeation/penetration

Keywords: EpiDerm, Iontophoretic Transport Paths, Lipids, ceramides, Percutaneous absorption, Percutaneous penetration, Skin models, cultured

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