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31 Results

Type: Article

Section: Testing > Sun Protection

Adjusting Substrate/Product Interfacial Properties to Improve In vivo/In vitro SPF Correlation

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.

Adjusting Substrate/Product Interfacial Properties to Improve In vivo/In vitro SPF Correlation

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.

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Editor's Note: Discontinuity and Your Inner Innovator

One innovative mash-up has been capturing consumer dollars: multifunctional color cosmetics. Whether fortified with SPF or moisturizing properties, makeup with added benefits is driving color sales. In relation, this month, we've created our own color and sun mash-up.

Interpretation of SPF In vivo Results: Analysis and Statistical Explanation

Methods for determining SPF in vivo are based on a biological response by human skin. To overcome intrinsic variation in these methods, large numbers of volunteers and statistics are required; however, these concepts are often poorly understood or worse, misinterpreted. This article discusses how these values should be interpreted and explains what they mean to formulators.

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Interpretation of SPF In vivo Results: Analysis and Statistical Explanation

Methods for determining SPF in vivo are based on a biological response by human skin. To overcome intrinsic variation in these methods, large numbers of volunteers and statistics are required; however, these concepts are often poorly understood or worse, misinterpreted. This article discusses how these values should be interpreted and explains what they mean to formulators.

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Are Your Sunscreens Infra-ready? New In vitro Method Puts Data Behind the Claims

Considering more and more sun care products are claiming infrared (IR) protection, it is important to standardize the parameters by which they are evaluated. Since IR-A and IR-B are the most implicated in skin damage, a test method was developed based on these wavelengths, as described here.

Determination of the In Vitro SPF

A ring test at six European test centers showed that SPF evaluations with good reproducibility and comparability could be obtained by an in vitro protocol measuring either transmittance or erythema-effective irradiance of product samples applied on PMMA plates.

Quantifying Sunscreens and Preservatives in Cosmetic Products

The authors propose and validate an HPLC method for simultaneous quantitation of commonly used commercial sunscreen actives and preservatives in cosmetic emulsions.

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Testing SPF 15–100, Indoor vs. Outdoor

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.

Testing SPF 15–100, Indoor vs. Outdoor

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.

Quantifying Benzophenone-3 and Octyl Methoxycinnamate in Sunscreen Emulsions

The authors have validated a high performance liquid chromatographic (HPLC) method for the quantitative determination of benzophenone- 3 and octyl methoxycinnamate present in sunscreen emulsions.

UV Transmission Assessment: Influence of Temperature on Substrate Surface

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.

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In vitro/vivo SPF Correlation and Repeatability According to Substrate

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.

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SPF Tests Reveal No Ideal In vitro Substrate Exists

In vitro SPF measurements are challenged by reproducibility, repeatability and correlation with in vivo values. Here, the authors assess sunscreen adhesion to the test substrate support, since poor adhesion produces bad results. Surface substrates are characterized by functional group, charge, wettability and surface morphology. Eight w/o and o/w emulsions also are tested. Results indicate an ideal in vitro test substrate does not exist.

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In Light of Exposure: Understanding Avobenzone Part I, Characterization

Avobenzone is a widely used UV-absorbing organic filter. Its dynamic nature and photophysical and photochemical properties are responsible for its widespread use. This first in a two-part series reviews its inherent characteristics and behavior in solvents; part two will consider its behavior with other sunscreens and in formulas.

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In Light of Exposure: Understanding Avobenzone Part II, Application

Avobenzone is a widely used organic UV filter. Its dynamic nature and unique properties are responsible for its widespread use and forms. This second in a two-part series considers avobenzone’s behavior with other sunscreens and in formulas; part one reviewed its characteristics and behavior in solvents.

Influence of Pressure During Spreading on UV Transmission Results

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.

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