Multicenter study on measurement of the natural pH of the skin surface

Segger, Dörte; Assmus, Ulrike; Brock, M.; Erasmy, J.; Finkel, P.; Fitzner, A.; Heuss, H.; Kortemeier, Uta; Munke, S.; Rheinländer, T.; Schmidt-Lewerkühne, H.; Schneider, Wilhelm; G, Weser

doi:10.1111/j.1468-2494.2007.00403_1.x

Cited by 53 publications

(40 citation statements)

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“…It forms an emulsion that solubilizes the sebaceous gland secretion and can also prevent water evaporation from the skin surface, thus contributing to keep skin hydrated. The values obtained in this assay were in agreement with the pH recommendations for topical formulations, which should present a pH value in the range of 5.0–6.0, similar to the pH of the stratum corneum hence preventing skin irritation .…”

Section: Resultssupporting

confidence: 85%

Development of a photoprotective and antioxidant nanoemulsion containing chitosan as an agent for improving skin retention

Cerqueira-Coutinho

Santos-Oliveira

Santos

et al. 2015

Engineering in Life Sciences

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Sunscreens are destined to topical application and should protect skin against ultraviolet radiation; furthermore, they are toxic substances and should not reach the bloodstream, so they must be retained in the skin. In the present work, an oil-inwater photoprotective and antioxidant nanoemulsion (NE) containing chitosan was developed. Preliminary studies were performed aiming to choose the surfactant to be used in this NE; stability of the formulas was determined by dynamic light scattering after their preparation and after 7 days. A blend of surfactants, polyoxyethylene sorbitan monooleate, and sorbitan monooleate was selected for the preparation of the NE, as well as the following organic sunscreens: benzophenone-3, diethylamino hydroxybenzoyl hexylbenzoate, octocrylene and octylmethoxycinnamate, and also pomegranate antioxidant extract and chitosan. The antioxidant extract with the highest antioxidant activity was chosen based on a screening of plant extracts by DPPH• (2,2-diphenyl-1-picrylhydrazyl) assay. Photostability of the sunscreens and in vitro efficacy and safety of the formulations were also evaluated. Results showed that the developed photoprotective and antioxidant NE containing chitosan was stable for at least 6 months, photostable when irradiated in a solar simulator, and effective. Additionally, chitosan acted by promoting retention of the formulation in epidermis, thus increasing formulation safety.

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Section: Resultssupporting

confidence: 85%

Development of a photoprotective and antioxidant nanoemulsion containing chitosan as an agent for improving skin retention

Cerqueira-Coutinho

Santos-Oliveira

Santos

et al. 2015

Engineering in Life Sciences

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“…Two w/o emulsions with different pH (pH 4 [WO 3741] vs pH 5.8 [WO 4081‐1]) were tested in elderly (aged 63.4 ± 6.8 years) subjects with Fitzpatrick skin type II and III. The pH of the emulsions was chosen as the lowest and highest pH of the skin reported by Segger et al . Mixture of glycolic acid and ammonia buffered pH to 4, while pH 5.8 emulsion did not contain the mix (difference for glycolic acid and ammonia was balanced with water).…”

Section: Methodsmentioning

confidence: 99%

Skin acidification with a water‐in‐oil emulsion (pH 4) restores disrupted epidermal barrier and improves structure of lipid lamellae in the elderly

Kilić

Masur

Reich

et al. 2019

The Journal of Dermatology

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The pH of the skin surface increases with age and thus reduces epidermal barrier function. Aged skin needs appropriate skin care to counterbalance age‐related pH increase and improve barrier function. This confirmatory randomized study investigated the efficacy of water‐in‐oil (w/o) emulsions with either pH 4 or pH 5.8 in 20 elderly subjects after 4 weeks of treatment. After the treatment, the skin was challenged with a sodium dodecyl sulphate (SDS) solution in order to analyze barrier protection properties of both formulations. The pH 4 w/o emulsion resulted in a significantly lower skin pH compared with the pH 5.8 w/o emulsion and an improved skin hydration after 4‐week treatment. Further, the pH 4 emulsion led to more pronounced improvements in length of intercellular lipid lamellae, lamellar organization as well as lipid levels than the pH 5.8 emulsion. Following SDS‐induced barrier damage to the skin, the pH of all test areas increased, but the area treated with the pH 4 emulsion showed the lowest increase compared with baseline. In addition, even after the SDS challenge the skin area treated with the pH 4 emulsion still maintained a significantly increased length of intercellular lipid lamellae compared with the beginning of the study. This study provides evidence that topical application of a w/o emulsion with pH 4 reacidifies the skin in elderly and has beneficial effects on skin moisturization, regeneration of lipid lamellae and lipid content. Application of a pH 4 emulsion can improve the epidermal barrier as well as the stratum corneum organization in aged skin.

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“…Additionally, it depends on genetic factors, co-morbidities and the medications or cosmetics used [33,35]. Sex most probably does not affect the differences in the pH value [5,10,33], although there are some reports suggesting that there is such correlation [34][35][36]. Also age does not modify this value, yet among new-borns and people above 80 years of age, higher pH values are noted [33,34,37].…”

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confidence: 99%

Structural and biophysical characteristics of human skin in maintaining proper epidermal barrier function

Boer¹,

Duchnik²,

Maleszka³

et al. 2016

pdia

185

194

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A b s t r a c tThe complex structure of human skin and its physicochemical properties turn it into an efficient outermost defence line against exogenous factors, and help maintain homeostasis of the human body. This role is played by the epidermal barrier with its major part -stratum corneum. The condition of the epidermal barrier depends on individual and environmental factors. The most important biophysical parameters characterizing the status of this barrier are the skin pH, epidermal hydration, transepidermal water loss and sebum excretion. The knowledge of biophysical skin processes may be useful for the implementation of prophylactic actions whose aim is to restore the barrier function.Key words: epidermal barrier, sebum, skin hydration, transepidermal water loss, skin pH. Skin is a barrier between the human body and the external environment. It protects the body against exogenous chemical and physical factors, takes part in the metabolic processes, plays a resorptive and thermoregulatory function, being the first line of defence against pathogenic microorganisms, and it partakes in immunological processes [1]. Review paperThe complex structure of human skin and its physicochemical characteristics turn it into an effective outermost defence line against exogenous factors, and help maintain homeostasis of the human body. This role is played by the epidermal barrier, in which the corneal layer of epidermis has a particularly important function to perform [1][2][3]. It consists of 15-20 layers of fully cornified keratinocytescorneocytes. In the bottom part of the cornified layer, the cells closely adjoin each other, while in the top part they are arranged loosely and undergo scaling. Construction of the corneal layer resembles a wall in which corneocytes stand for bricks, and a fat-abundant intercellular matrix is the cement [4,5]. The interior of the corneal layer cells is filled with cytokeratin filaments bonded with filaggrin. These cells are surrounded by a stiff, cornified encasement built mostly of the loricrin protein, forming a part of the so-called protein-lipid envelope [2,3,6]. The envelope is connected with the extracellular liquid crystal matrix and constitutes the border between the hydrophilic surface of the cells and the lipophilic non-polar fatty acids of the matrix surrounding corneocytes [7].The thickness of the outer layer of the epidermis, the size of corneocytes, and the composition of superficial lipids impact the regenerative properties of the skin, which contributes to the various courses of dermatological diseases, and the process of healing alike. Anatomical areas with thick epidermis are more resistant to external factors [8]. On the other hand, the areas with a relatively thin cornified layer, such as the face, are characterized by high susceptibility to damaging factors, but also by the ability to re-establish the barrier function very fast. It is connected with a high proliferative activity, thus quick regeneration of the epidermis, intensive vascularity, good hydration, and pr...

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Multicenter study on measurement of the natural pH of the skin surface

Cited by 53 publications

References 0 publications

Development of a photoprotective and antioxidant nanoemulsion containing chitosan as an agent for improving skin retention

Development of a photoprotective and antioxidant nanoemulsion containing chitosan as an agent for improving skin retention

Skin acidification with a water‐in‐oil emulsion (pH 4) restores disrupted epidermal barrier and improves structure of lipid lamellae in the elderly

Structural and biophysical characteristics of human skin in maintaining proper epidermal barrier function

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