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

Acidic pH of the skin surface has been recognized as a regulating factor for the maintenance of the stratum corneum homeostasis and barrier permeability. The most important functions of acidic pH seem to be related to the keratinocyte differentiation process, the formation and function of epidermal lipids and the corneocyte lipid envelope, the maintenance of the skin microbiome and, consequently, skin disturbances and diseases. As acknowledged extrinsic factors that affect skin pH, topically applied products could contribute to skin health maintenance via skin pH value control. The obtained knowledge on skins’ pH could be used in the formulation of more effective topical products, which would add to the development of the so-called products ‘for skin health maintenance’. There is a high level of agreement that topical products should be acidified and possess pH in the range of 4 to 6. However, formulators, dermatologists and consumers would benefit from some more precise guidance concerning favorable products pH values and the selection of cosmetic ingredients which could be responsible for acidification, together with a more extensive understanding of the mechanisms underlaying the process of skin acidification by topical products.

Optimization of Skin Moisturizer Formula Based on Fixed Oil (VCO, Olive Oil, and Jojoba Oil)

Currently, formulations of skin moisturizers are derived from natural compounds. Fixed oils are known to have compounds that potential to be developed as skin moisturizers based on emollient mechanism. Therefore, this study aims to determine the effect of oil type on the physical characteristics of skin moisturizer creams. In this study, a skin moisturizer cream was formulated using three types of fixed oils: VCO (F1), Olive Oil (F2), and Jojoba Oil (F3). All formulas were tested for physical characteristics of pH, cream type, viscosity, spreadability, and homogeneity. The test results show that all formulas appropriate to the skin pH range, have o/w type creams and homogeneous texture. In the results of the viscosity test, there was a significant difference (p<0.05) with the highest value of viscosity for F2 (16750 ± 250 cP) > F3 (14200 ± 346cP) > F1 (5833 ± 58 cP), while for spreadability test there were also significant differences (p<0.05) with the highest diameter for F1 (5.8 ± 0.1 cm) = F3 (5.7 ± 0.2 cm) > F2 (4.3 ± 0.2 cm). Based on the results, it can be concluded that the type of oil can affect the physical characteristics of the moisturizer formula. F1 and F3 have better physical characteristics than F2.

Instrumental possibilities of skin parameters assessment — literature review

The authors reviewed the literature on the most commonly used devices for measuring skin parameters. The instruments were selected to measure: skin elasticity Cutometer® (Courage-Khazaka, Koln, Germany), Reviscometer® RVM600; hydration while using skin properties such as resistance, capacity, conductivity and impedance, the Corneometer CM 820 and CM 825 (Courage & Khazaka, Koln, Germany), Nova DPM 9003 (Nova Technology Corporation, Gloucester, MA, USA), DermaLab® USB Moisture Module (Cortex Technology, Hadsund, Denmark) and Scalar Moisture Checker MY-808S (Scalar Corporation, Japan), to test percutaneous water loss (TEWL) with Tewameter® TM 300 (Courage-Khazaka, Koln, Germany); high-frequency ultrasound scanners Dub®SkinScanner 75 (TPM Company, Lueneburg, Germany), DermaScan® C USB (Cortex Technology, Hadsund, Denmark); for pH measurement Skin-pH-Meter PH 905 (Courage-Khazaka, Koln, Germany), Skin-pH-Meter PH 900 (Courage-Khazaka, Koln, Germany, pH-Meter 1140 (Mettler Toledo, Urdorf, Switzerland); skin sebum is tested by Sebumeter® SM 815 (Courage-Khazaka, Koln, Germany); the Mexameter® MX 18 (Courage-Khazaka, Koln, Germany), CM-2600d Spectrophotometer (Konica Minolta, Tokyo, Japan) and Minolta Chromameter CR-200 (Konica Minolta, Tokyo, Japan. The analysis of measuring devices available on the market introduces the mechanism of their operation and application.

Dynamic Trends in Skin Barrier Function From Birth to Age 6 Months and Infantile Atopic Dermatitis: A Chinese Prospective Cohort Study

BackgroundSkin barrier functions develop after birth and may be related to skin disorders in infants. ObjectivesWe aimed to assess associations between dynamic trends of four skin barrier functional parameters in early life with infant atopic dermatitis (AD).MethodsBased on the prospective cohort MKNFOAD (NCT02889081), we examined transepidermal water loss (TEWL), stratum corneum hydration (SCH), skin pH, and sebum content at five anatomical sites (cheek, forehead, forearm, abdomen, and lower leg) in 418 term infants at birth, 42 days, and 6 months. Trend differences by sex and association with AD at age 1 year were tested using variance analyses. Associations of the parameters with AD risk were tested using discrete time survival analysis, adjusting extensive covariates including parental history of allergy, infant’s sex, birth weight (kg), and delivery mode. Odds ratios (ORs) and 95% confidence interval (CIs) were reported.ResultsOverall TEWL and SCH appeared trends of increase while skin surface pH and sebum content showed trends of decrease within the first 6 postnatal months. Sex differences were significant for sebum content only (p<0.001). After adjustment for parental and children covariates, cheek TEWL (OR=1.26, 95% CI 1.00–1.57, p=0.045) at birth and 42 days (OR=1.52, 95% CI 1.17–1.97, p=0.002) were significantly associated with increased AD risk. Associations were not observed between SCH, skin pH, and sebum content at birth or 42 days with AD. ConclusionsSkin barrier functions of Chinese term infants varied nonlinearly after birth. Higher postnatal TEWL levels in early life indicate higher risk of early-onset AD.