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This work evaluates the impact of applied pressure during sample spreading on the in vitro measurement of UV transmission. The authors work in a range of pressures between 50–200 g and demonstrate that pressure control is a key parameter that should be strictly controlled to ensure the reliability of test results.
According to Merriam-Webster, phenomenology is the study of consciousness and self-awareness as a philosophy. Putting this with epidermic led me to what the industry now considers wellness and corneocare, which Steventon describes.
Repeatability and reproducibility are crucial to validate any test method. In order to master these criteria, the authors developed an automated spreading device and compared it with human spreading. Application of the device in eight laboratories and using 36 sunscreens revealed great improvements via automated spreading, ensuring good intra- and inter-laboratory variability.
If like me, you’re just daydreaming of the beach, this collection of articles will enlighten you with its focus on sun protection, SPF testing, damage repair and more.
This work evaluates the impact of three different substrates on in vitro SPF measurements, and defines experimental conditions to improve their correlation with in vivo values. Evaluations of 32 products, shown here, led the authors to conclude that molded substrates improved repeatability and correlation with in vivo SPF values.
Lab tests on sunscreens show it takes more energy to produce mild erythema on protected skin than unprotected skin. Yet the FDA questions the need for SPFs higher than 50. In response, two outdoor studies were conducted using commercial products to challenge standing premises and determine if there is a measurable difference in an SPF 100 and SPFs of 50 or less.
There are various test methods set by global governing bodies for SPF protection, but this article will discuss the five time-point internationally approved ISO 24444 method.
This work evaluates the impact of temperature on test substrate surfaces during the application, spreading and drying steps of the in vitro method to measure ultraviolet (UV) transmission. The authors work in a range between 20°C and 35°C, and demonstrate that controlling temperature is a key test parameter that should be strictly controlled to ensure reliability.
This work evaluates the impact of a plasma treatment on test substrates to modify their surface energy, to more closely correlate in vitro SPF measurements with in vivo measurements—without chemically altering the test products. The authors chose the level of plasma modification to use on a substrate based on in vivo values; they explain how to choose it regarding specific formulas in a further paper.
Cosmetics & Toiletries is pleased to welcome Marc Pissavini, PhD, to its prestigious Scientific Advisory Board. Pissavini began his career as an analytical chemist and in 1998, joined the sun research department of Coty-Lancaster in Monaco. Since 2008, he has served as the director of Basic and Applied Research for the company.