A 10% Lactobionic acid‐containing moisturizer reduces skin surface pH without irritation—An in vivo/in vitro study

Abstract

Summary Background/Objectives Stratum corneum acidification is a newer strategy in management of inflammatory dermatoses; acidifying emollients are normally used for that purpose. However, a decrease in pH of the skin is commonly connected to an increase in irritation. The aim of this study was to investigate whether lactobionic acid (LA), cosmeceutical active and "superacid" belonging to the class of alpha‐hydroxy acids (AHAs), could decrease pH of skin surface without irritation. Methods Safety profile of emulsion based on alkyl polyglucosides (APGs) sugar emulsifiers with 10% LA was evaluated in vitro (acute skin irritation test using cytotoxicity assay), and in vivo in safety study employing measurements of the relevant biophysical human skin parameters upon cessation of 24 hours occlusive treatment: transepidermal water loss (TEWL), stratum corneum hydration (SCH), and skin erythema index (EI). The effect on the pH of human skin surface was investigated by pH measurements prior and 1 hour after application of the emulsion with 10% LA. Results The pH of the skin was significantly reduced after application of LA‐containing emulsion. The results for in vitro skin irritation potential assessment were in line with the in vivo safety study, indicating a satisfactory safety profile of both APG‐based emulsion vehicle per se and emulsion with 10% LA. Conclusion Lactobionic acid (10%) in emulsion based on APGs reduces skin surface pH without irritation and skin barrier impairment; it could be proposed as an alternative to low‐molecular AHAs in acidifying emollients.

Towards Optimal pH of the Skin and Topical Formulations: From the Current State of the Art to Tailored Products

“…In a recent study, Lukic et al have shown that topical products could induce skin acidification and that the effect is not in direct reciprocity to a products' pH, although this depends on the presence of ingredients which are proton donors and on the activity of a skin buffering system [140]. Due to numerous difficulties related to the formulation of topical products with such actives, investigations in this field are still drawing great attention in relation to the development of stabile and safe products with rather low pH [87,140,141]. Undoubtedly, research in this area should be deepened by the interlinking efficacy of these products with skin pH formation, maintenance and acid microdomains.…”

Comparison of novel aluminium lactate versus aluminium chloride‐based antiperspirant in excessive axillary perspiration: First prospective cohort study

“…An increase in the pH-value can give rise to an alteration of normal skin physiology and thus affect its barrier function among others, facilitating the growth of pathogenic bacteria that play a major part in skin conditions such as atopic eczema. 16 Interestingly, no significant differences with regard to the prevalence of skin irritations and the dropout rates could be observed between participants with a positive versus a negative medical history for atopic eczema. In other words, our study provided no evidence that individuals with a sensitive skin type (such as atopic skin) were at a greater risk for developing skin irritations than participants without atopic skin when using the two preparations being evaluated.…”

“…Intertriginous and damp skin areas such as the armpits have a slightly higher pH‐value. An increase in the pH‐value can give rise to an alteration of normal skin physiology and thus affect its barrier function among others, facilitating the growth of pathogenic bacteria that play a major part in skin conditions such as atopic eczema 16 …”

Standardized wild apple fruit extract as a bioactive agent in dermocosmetic products for efficacy skin hydration—In vitro and in vivo evaluation

“…Beside their antioxidant activity, these bioactive substances might effectively moisturize the skin and regulate barrier function and skin pH values, which all lead to improvement of general condition and appearance of healthy skin 6,10,11 . In addition, stability, safety, and efficacy of these bioactive substances from plant extract is in line with the current needs and expectations of modern consumers/users 1,6,8,10‐15 …”