In vitro human nail penetration and kinetics of panthenol
The in vitro absorption of panthenol into and through the human nail was examined in this study. Panthenol, the alcohol form of pantothenic acid (vitamin B5), is believed to act as a humectant and improve the flexibility and strength of nails. A liquid nail treatment formulated with panthenol (2%) was compared to a solution of panthenol (2%) in water. Fingernail specimens were dosed daily for 7 days with either the nail treatment (non-lacquer film forming) formulation or aqueous solution with sampling performed every 24 h. Panthenol concentrations were determined in the dorsal surface, interior (by drilling and removal) and in the supporting bed under the human nail. Panthenol levels in the dorsal nail (R2 = 0.87; P < 0.001), nail interior (R2 = 0.94; P < 0.001) and nail supporting bed (R2 = 0.79; P < 0.003) showed a significant linear increase with each day of dosing. Significantly more panthenol was delivered into the interior nail and supporting bed by a nail treatment formulation than from an aqueous solution. The film acts not only as a reservoir of panthenol, but also acts to increase the hydration of the nail and the thermodynamic activity of panthenol as well, thereby enhancing diffusion.
Document Type: Research Article
Affiliations: 1: Dermatology, University of California San Francisco, Surge 110, Box 0989, 90 Medical Center Way, San Francisco, CA 94143 2: Neutrogena Corp., 5760 West 96ht Street, R&D Building, Los Angeles, CA 90045, U.S.A.
Publication date: August 1, 2007