Impact of a pH 5 Oil-in-Water Emulsion on Skin Surface pH

• Published in: Skin pharmacology and physiology Vol. 30; no. 6; pp. 292 - 297
• Main Authors: Fürtjes, Theresa, Weiss, Katharina T., Filbry, Alexander, Rippke, Frank, Schreml, Stephan
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 01.01.2017
• Subjects: Original Paper; Acidification; Human skin; Epidermal barrier; pH value; Topical application
• ISSN: 1660-5527; 1660-5535
• DOI: 10.1159/000480300

Background: Human skin surface has a physiologically acidic pH (pH ss ). In cases of increased pH ss , the acidity of the skin can be restored by topical formulations. We tested a pH 5 oil-in-water (O/W) emulsion for pH ss regeneration and stabilization. Methods: We performed 2 experiments with 10 female study subjects in each. In both experiments, 2D imaging with luminescent sensor foils was used to determine pH ss . Alkalization was reached by washing the volar forearm with a soap bar and warm running tap water for 20 min. Experiment 1: after defining the baseline pH ss , we alkalized the respective area and measured pH ss over a duration of 5 h, while applying emulsion every hour. Experiment 2: study subjects used the emulsion twice daily for 1 week. Then, pH ss was measured before and after 5 min of washing a treated and an untreated area on the volar forearm. Results: (1) 5 h after alkalization, the treated arm showed a significantly lower pH ss than the untreated one (5.87 ± 0.03 vs. 6.05 ± 0.03); (2) after washing, the treated area had a significantly lower pH ss than controls (6.13 ± 0.03 vs. 6.27 ± 0.05). Conclusions: The tested pH 5 O/W emulsion seems to improve regeneration and stabilization of pH ss .