Electroosmotic pore transport in human skin
Olivia D Uitto1, Henry S White
1Department of Chemistry, University of Utah, Salt Lake City, Utah, USA.
Pharmaceutical Research
|May 13, 2003
Summary
Electroosmotic flow in human skin occurs in shunt pathways like hair follicles, not just stratum corneum pores. This flow, driven by iontophoresis, originates from charged nanopores beneath the skin surface.
Area of Science:
- Dermatology
- Biophysics
- Materials Science
Background:
- Understanding electroosmotic flow (EOF) is crucial for transdermal drug delivery.
- Human skin presents complex pathways influencing fluid dynamics.
Purpose of the Study:
- To elucidate the specific pathways and origin of electroosmotic flow within human skin.
- To differentiate EOF contributions in various skin layers and pore structures.
Main Methods:
- Scanning electrochemical microscopy (SECM) visualized and quantified iontophoretic transport of acetaminophen.
- Comparison of EOF in full-thickness skin shunt pathways, stratum corneum pores, and synthetic membranes.
- Laser scanning confocal microscopy (LSCM) assessed rhodamine 6G penetration into pore structures.
Main Results:
- EOF was detected in shunt pathways (hair follicles, sweat glands) of full-thickness human skin, but absent in freestanding stratum corneum pores.
- Acetaminophen's diffusive and iontophoretic pore fluxes were quantified in full-thickness skin.
- Rhodamine 6G penetrated approximately 200 micrometers along pore pathways.
Conclusions:
- Iontophoresis induces localized EOF along skin's pore shunt paths.
- EOF originates from current passage through negatively charged meso/nanoscale pores beneath the stratum corneum.
- These findings clarify EOF mechanisms in skin, impacting transdermal delivery system design.
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