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High-frequency sonophoresis: permeation pathways and structural basis for enhanced permeability
G K Menon1, D B Bommannan, P M Elias
1Dermatology Service, Veterans Administration Medical Center, San Francisco, Calif 94121.
Skin Pharmacology : the Official Journal of the Skin Pharmacology Society
|January 1, 1994
Summary
Ultrasound (sonophoresis) alters skin structure by disrupting stratum corneum bilayers, creating pathways for enhanced permeation. These structural changes temporarily increase skin permeability for topical agents.
Area of Science:
- Dermatology
- Biophysics
- Materials Science
Background:
- The mechanism of stratum corneum (SC) permeabilization by ultrasound (sonophoresis) remains largely unknown.
- Understanding SC structural changes is crucial for optimizing transdermal drug delivery.
Purpose of the Study:
- To investigate the permeation pathways and SC intercellular structural organization after high-frequency sonophoresis.
- To elucidate the mechanisms and kinetics of sonophoresis-induced skin permeabilization.
Main Methods:
- Hairless mouse skin models were subjected to high-frequency sonophoresis.
- Ruthenium tetroxide post-fixation was used to preserve tissue structure.
- Tracer solutions (LaNO3, FITC-dextrans) were employed to visualize permeation pathways.
Main Results:
- Sonophoresis disrupted the compact organization of SC bilayers and lamellar body contents at the stratum granulosum (SG)-SC interface.
- Domain separation within SC bilayers was observed between 0 and 20 hours, reverting by 48 hours.
- Tracers permeated the SC via lacunae within lamellar bilayers and through separated lamellar domains.
Conclusions:
- Sonophoresis induces temporary, reversible structural changes in the stratum corneum.
- These alterations create distinct intercellular pathways for enhanced skin permeation.
- The findings provide insights into sonophoresis mechanisms for transdermal delivery.