86 SUN CARE This new hybrid measurement principle
combines spectroscopic in vivo and in vitro data (HDRS). The ISO technical committee TC 217 (Cosmetics) is simultaneously working on a new ISO norm for the HDRS method. Courage+Khazaka has developed a new
system to measure UV reflectance in vivo directly on the skin, which uses UV-LED technology and a sensitive spectroscopic system. The UV dose applied does not cause sunburn and the SPF is determined based on the measured light attenuation of the sunscreen. 4. Quantification and stability analysis of UV filters UV filters can lead to a partial or complete loss of their effectiveness or even to a possible transformation into a hazard substance and undesirable byproducts. Laboratories work to anticipate physical and chemical degradation of raw materials based on photodegradation and new criteria (chemical and toxicological) to ensure the safety of sun care products. However, it has been demonstrated that some skin reactions due to photoallergic contact are caused by using many commonly organic sunscreens. In this context, the maximum content of UV filter in products has been limited in cosmetics by the European Commission (Annex VI-1223/2009). Different instrumental techniques are
used to analyze the UV filters, e.g. NMR spectroscopy, Raman spectroscopy, gas chromatography/mass spectrometry, and high-performance liquid chromatography/UV detector. 5. Oxidative stress assays Solar radiations penetrate the skin, and their energy is absorbed by constitutive molecules, with consecutive damages like oxidation and inflammation. Evolution brought effective defences such as pigmentation to quench radiations, anti-oxidation, and clearance processes. However, an excess of sun exposure
disrupts those self-defences, leading to uncontrolled reactive oxygen species (ROS) production, DNA damages, proinflammatory response and microbial dysbiosis. Many of these mechanisms can be evaluated with controlled radiations on 3D skin models studying various biological markers and cell signalling pathways, e.g. ROS, Nrf- 2 activation, heme-oxygenase (HO-1) expression, caspase-3 activation, and microbiota.
proved that oxybenzone was responsible for coral bleaching and disruption of the development of a new ecosystem. Since 1 January 2021, Hawaii prohibits the
over-the-counter sale of sunscreen products containing oxybenzone and octinoxate, chemical compounds they consider to be particularly dangerous to the balance of the marine environment. A recent review of environmental
contamination and potential health impacts on aquatic life from active chemicals in sunscreen formulations by Australian pharmaceutical chemist Nial J. Wheate was published in March 2022 in the Australian Journal of Chemistry. In this paper, it states that the level of sunscreen chemicals found in samples varies considerably between regions, time of year - it is higher in summer months - and the time of day.
This paper confirms numerous studies stating active chemicals in sunscreens can have potential impact on hormonal/ oestrogenic activity and non-hormonal effects, including acting as teratogens, altering gene regulation, inducing changes in antioxidant and free radical production, and inducing coral bleaching. Wheate found that when damage does
The impact on the marine environment Many consumers are now extremely sensitive to the impact of the use of cosmetic products on the environment. Younger generations of consumers can refuse to use certain products if they do not meet Vegan criteria, for example. It is the same for the use of solar products that bring attention to their impact on aquatic environments, marine life and even corals. The Hawaiian archipelago has seen the
gradual disappearance of corals and its marine life caused by the pollution of certain chemical compounds present in sunscreens. In 2015, a study by the University of Central Florida
PERSONAL CARE October 2022
occur to reefs and animal life, there are often other causes that have a higher impact, including changes in water temperature, water turbidity, elevated nutrient levels, and the presence of pesticides and medicines used for human and animal health. It should be noted that not all sun care
filters have been studied for their impact on the marine environment and it would be not appropriate to make broad generalisations about sunscreen ingredients and their ability to cause damage to aquatic life. Sun care products are cosmetic
formulations that protect the skin from the sun damage through the scattering or the absorption of the UV lights. They are formulated with various ingredients and chemicals including oils, surfactants, fragrances, preservatives, and filters. These
filters come from two types of chemicals: metal oxides (i.e. zinc or titanium) with a scattering action, and organic chemicals with absorption characteristics.
Ecotoxicology studies Zebrafish feature in many ecotoxicology studies and are well recognised for used in standardised models for this type of research. Zebrafish are easy and cheap to source, and, as this species shares some genetic, physiological, and anatomical similarities with mammals, are routinely used to study the effect of chemicals on vertebrate embryonic development. Furthermore, they have transparent bodies, so direct visualisation of organ development is straightforward. To evaluate endocrinian activity,
translucent embryos are used as an in vitro test to measure thyroid activity of an ingredient or a formula. A fluorescent biomarker reveals the endocrine activity. In this model, the thyroid signalisation
is revealed by a modification of the level of fluorescence of the larvae in the brain with an increase in the case of pro-thyroid effect and a decrease in the case of anti-thyroid effect. Larvae are placed into exposure solution. Each sample is tested alone or in co-
treatment with reference thyroid hormone. This co-treatment enables activation of the thyroid axis of the larvae and therefore the detection of synergistic or inhibitor effects on the axis. The results can be expressed as hormonal equivalents. This analysis allows the identification of
the concentration of the thyroid hormone T3, which gives an equivalent effect to that of the sample. This analysis allows the identification of the concentration of the testosterone or flutamide which gives an equivalent effect to that of the sample. Moreover, for marine ecotoxicity there is an ISO norm (16712) that enables the study of the acute toxicity of marine or estuarine sediments to amphipods (Corophium arenarium), which typically live below the sediment surface and are exposed
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