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A Dermatological View—In vitro Buffering Capacity of Human Skin Layers

By: Y. Zheng, MD, PhD, Third Affiliated Hospital of Sun Yat-sen University, and H.I. Maibach, MD, University of California at San Francisco

Posted: June 4, 2012, from the June 2012 issue of Cosmetics & Toiletries.

Normal stratum corneum (SC) is acidic, with typical pH ranges from 4 to 6, and while skin exposed to aqueous acid or alkaline solutions exhibits changes in pH, it may rapidly restore to the baseline values. This phenomena is called buffering capacity. Many factors contribute to skin’s buffering capacity including keratin, proteins, sweat, SC thickness, free amino acids and other water-soluble epidermis constituents. Previous studies demonstrate that skin buffering capacity can be measured in vitro by applying several concentrations of hydrogen chloride (HCl) and sodium hydroxide (NaOH) on skin and evaluating the pH change pre- and post-dosing. Here, the authors employed this technique to evaluate the buffering capacity of skin layers including intact SC, denuded SC and dermis skin samples.

This is only an excerpt of the full article that appeared in Cosmetics & Toiletries, but you can purchase the full-text version.