V. R. Leite-Silva and colleagues applied topical nano zinc oxide to volunteers and asked whether occlusion or barrier impairment let the particles into living epidermis. The DOI printed in the paper is 10.1016/j.ejpb.2016.04.022.
Key numbers
The authors report that the nanoparticles did not penetrate into the viable epidermis of intact skin or of barrier-impaired skin, with or without occlusion. The preparation was 10% w/v zinc oxide, applied at the standard SPF-testing dose printed as 2 mg cm2, for 6 h. Those three figures are dose parameters. They are not concentrations measured inside viable epidermis.
Methods (brief)
Human volunteers, topical nano zinc oxide, occlusion and barrier impairment as experimental factors.
Evidence fitness
The page supports that qualitative penetration result. It does not support an occurrence concentration in a sunscreen product.
Limitations
The applied dose, formulation, and 6 h duration are recorded. Numeric depths inside the skin were not transcribed.
Related evidence
- Sun/suntan products (including spray, self-tan, airbrush)
- Zinc
- Relative penetration of zinc oxide and zinc ions into human skin after application of different zinc oxide formulations
Update history
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