Ex-vivo spectroscopic quantification of sunscreen efficacy: proposal of a universal sun protection factor

et al. 2012

The objective of the present investigation was to examine the utilization of optical and spectroscopic methods for the noninvasive characterization of Anthelios XL Fluide Extreme (SPF 50+), an exemplary sunscreen, concerning its homogeneity of distribution on the skin, its spectroscopic properties and its overall protective efficacy. The homogeneity of the distribution of the sunscreen on the skin was investigated with a multiphoton tomography microscope. Additionally, the sum transmission spectrum was determined using tape stripping and spectroscopic measurements. The results revealed a very homogeneous distribution of the sunscreen on the skin surface and also in the deep furrows. The sum transmission spectrum reflects a high protective efficacy of the sunscreen in both the UVA and UVB ranges. The sunscreen Anthelios XL Fluide Extreme (SPF 50+) generates a comfortable feeling on the skin and can be easily distributed. The presented optical methods have been shown to be suitable to investigate the overall protective efficacy of sunscreen products objectively, noninvasively and quickly.

Section: Methodsmentioning

confidence: 99%

“…Tape stripping in combination with spectroscopic measurements is a well-established method to overcome the difficulties that arise with SPF determinations [13,14]. It has been demonstrated that the mean values of the average sum transmission in the UVB range correlate to the SPF at a high accuracy.…”

Section: Introductionmentioning

confidence: 99%

Methods for the Evaluation of the Protective Efficacy of Sunscreen Products

Vergou

Patzelt

et al. 2012

“…The rough surface profile of the skin substantially reduces the efficiency and SPF of sun care products [22,28,29]. Active filters accumulate in the furrows and wrinkles of the skin and due to their inhomogeneous distribution reduce the UV absorption capacity by a factor of up to 10 [11].…”

Section: Discussionmentioning

confidence: 99%

“…This approved, minimally invasive method enables the penetration, secretion and reservoir properties of endogenous or topically applied substances in the stratum corneum of the skin to be studied under in vivo conditions. Inter alia, this method has been used previously to investigate UV filter characteristics and external influences on sunscreen behavior and efficiency [11,18,19,20,21,22]. …”

Section: Introductionmentioning

confidence: 99%

Gain or Loss? Sunscreen Efficiency after Cosmetic Pretreatment of the Skin

Kluschke

Weigmann²,

et al. 2013

Sunscreens are a key pillar of the multimodal protection strategy against short- and long-term impacts of intermittent and continuous UV exposure. Hitherto, an unanswered part of current scientific discourse is the question whether a cosmetic pretreatment has an impact on distribution and adhesiveness of sunscreens on the skin and therefore affects UV protection. In order to evaluate the homogeneity of sunscreen filter distribution, water resistance as a parameter of adhesiveness and effective UV protection of sunscreens after a pretreatment with cream or lotion was investigated in 18 volunteers who were examined before and after swimming, using the established combination of the tape stripping procedure and UV/VIS spectroscopy. It was shown that a cosmetic skin pretreatment affects neither filter homogeneity nor effective UV protection prior to water contact. However, compared to nonpretreated skin, a considerable loss of water resistance is caused. Therefore, using a cream or lotion before application of sunscreens is not to be recommended.

“…Based on different mechanisms, several authors have proposed new methods to determine sunscreen efficacy in a more comprehensive manner [9,10,11], inter alia, the universal SPF (USPF) [12] and the radical formation ratio (RF) [13], which is based on electron paramagnetic resonance (EPR) measurements.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Model Sunscreen Formulations Comparing the Sun Protection Factor, the Universal Sun Protection Factor and the Radical Formation Ratio

Syring

Weigmann²,

et al. 2015

Self Cite

In view of globally rising skin cancer rates and harmful effects exerted by sunlight throughout the ultraviolet, visible and infrared ranges, an objective, safe and comprehensive method for determining sunscreen efficacy is required in order to warrant safe sun exposure. In this study, the influence of characteristic active ingredients (chemical filters, physical filters and antioxidants) on different sunscreen indicators, including the universal sun protection factor and the radical formation ratio, was determined and compared to their influence on sun protection factor values. Spectroscopic universal sun protection factor measurements were conducted ex vivo by analyzing tape strips taken from human skin, and radical formation ratio determination was performed via electron paramagnetic resonance spectroscopy using porcine ear skin ex vivo. The sun protection factor determination was conducted according to ISO standards (ISO 24444:2010). It was shown that chemical filters provide a protective effect which was measurable by all methods examined (spectroscopy, electron paramagnetic resonance spectroscopy and erythema formation). Physical filters, when used as single active ingredients, increased protective values in universal sun protection factor and sun protection factor measurements but exhibited no significant effect on universal sun protection factor measurements when used in combination with chemical filters or antioxidants. Antioxidants were shown to increase sun protection factor values. Radical formation ratio values were shown to be influenced merely by chemical filters, leading to the conclusion that the universal sun protection factor is the most suitable efficacy indicator for the ultraviolet range.