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UVA Absorbers (uva + absorber)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Sunscreens containing the broad-spectrum UVA absorber, Mexoryl® SX, prevent the cutaneous detrimental effects of UV exposure: a review of clinical study results

PHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 4 2008
Anny Fourtanier
Background: UVA exposure of human skin mainly produces reactive oxygen species (ROS) leading to DNA, cell and tissue damage. It alters immune function, pigmentation and it is certainly responsible for a large part of photoaging changes. Moreover UVA is implicated in the etiology of several photodermatoses. As a consequence, to provide adequate protection, sunscreens or skin care products for daily use protective products need UVA absorbers combined with UVB ones. Aim: To assess the efficacy of sunscreens containing a broad-spectrum UVA absorber the Mexoryl® SX or ecamsule and to compare formulations with and without it through a large number of clinical studies in human volunteers and patients. Methods: The following assessments were conducted: ,Prevention of excessive pigmentation induced by UV exposure in Caucasian and Asian skins using a method that measures pigmentation protection factors (PPF). ,Efficacy against DNA damage by measurement of pyrimidine dimer formation and p53 protein accumulation. ,Protection of immune system using delayed type hypersensitivity (DTH) reactions to recall antigens, isomerization of urocanic acid (UCA), alteration of Langerhans cells (LC) density, morphology and function. ,Reduction of epidermal and dermal alterations induced by repeated UVA or UV solar simulated radiation (SSR) using histology or immunohistology. ,Prevention of the polymorphous light eruption (PMLE) in patients prone to develop this disease. Results: Mexoryl® SX-containing formulations showed a dose-dependent level of protection against pigmentation. For a same sun protection factor (SPF) the higher the UVA protection was, the higher was the PPF. Pyrimidine dimer formation and p53 accumulation were significantly reduced by formulations with Mexoryl® SX. In the studies looking at the suppression of DTH reactions to recall antigens by the different UV spectra, the LC alterations and the cis UCA formation, Mexoryl® SX formulations always showed a higher protective potency than sunscreen without it even when the protection against erythema was similar (products with same SPF). Mexoryl® SX formulations also prevented or significantly decreased to minimal, ferritin, tenascin and lysozyme expression induced by repeated UVA or SSR exposure. It also reduced the enhancement of collagenase 2 mRNA expression induced by SSR exposure. Finally PMLE study demonstrated that UVA protection was essential for the prevention of this photodermatose. Conclusion: Mexoryl® SX formulated in sunscreens or daily use products have been shown to be an effective UV absorber, leading to an increased efficacy of these products against a large number of biological damage induced by UVA, SSR or sun exposure. [source]

Fading of artificial hair colour and its prevention by photofilters

INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 3 2006
B. Locke
Fading of artificial hair colour has been investigated by simulating actual usage conditions through exposure to artificial radiation in a weatherometer, with 0.35 mW (m2nm),1 at 340 nm, for 16,48 h, and by periodical washing. Hair colour was produced by using commercial two-part, permanent hair dyes with light auburn, medium auburn and dark auburn shades. Formulations based on red couplers, such as 4-amino-2-hydroxytoluene and 1-naphthol, as well as primary intermediates, such as 1-hydroxyethyl-4,5-diamino pyrazole sulphate, were employed. Results indicate that the extent of fading, as measured by the total colour change parameter, dE, is greatest for coloured hair subjected to both irradiation and shampooing, and significantly smaller for hair undergoing only irradiation or washing. Colour loss has been also found to be dependent upon the hair type employed, with coloured natural white and bleached hair undergoing much greater change than coloured brown hair. It has been also shown that hair colour based on pyrazole intermediates displayed the deepest fading as a result of shampooing (dE 4,6 after 10 shampooings) and irradiation per shampooing (dE 14,16 after 32 h of light exposure and four shampooings). The contribution of UV light (UVB + UVA) to the artificial hair-colour loss was found experimentally to be dependent upon the irradiation dose and varied from 63% at 16 h of irradiation time to 27% at 48 h of light exposure. The theoretical extent of photoprotection by a formulation was assessed by calculating the percentage of UV light it attenuates in the wavelength range from 290 to 400 nm. The results indicate that UVB photofilters, such as octyl methoxy cinnamate, absorb <25% of the total UV irradiation at concentrations as high as 30 mg (g hair),1. UVA absorbers were found to be more effective, with benzophenone-3 and benzophenone-4 absorbing about 40% of UV at the same concentration. Corresponding experimental data were in reasonable agreement with the theoretical predictions. The data are also presented for colour protection with treatments containing two photo-absorbers: benzophenone-3,ZnO; benzophenone-4,ZnO; octyl methoxy cinnamate,ZnO; and dimethylpabaimidopropyl laurdimonium tosylate-benzophenone-3. [source]

Sunscreens containing the broad-spectrum UVA absorber, Mexoryl® SX, prevent the cutaneous detrimental effects of UV exposure: a review of clinical study results

A full-UV spectrum absorbing daily use cream protects human skin against biological changes occurring in photoaging

PHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 4 2000
S. Seité
Background: There is overwhelming evidence that exposure of human skin to ultraviolet radiations (UVR) leads to the development of cutaneous photoaging and eventually to neoplasia. This study was designed to evaluate in humans the protection afforded by a daily use cream containing a photostable combination of UVB and UVA absorbers (Uvinul® N539, Parsol® 1789 and Mexoryl® SX) providing a continuous absorption through the entire UV spectrum, against damages induced by repeated daily exposure to solar simulated radiation (SSR). Methods: Buttock skin of 12 healthy volunteers was exposed 5 days per week for 6 weeks to one minimal erythema dose of solar simulated radiation per exposure. The following parameters in treated and untreated skin were evaluated: erythema, pigmentation, skin hydration, skin microtopography, histology and immunochemistry, and collagen and metalloproteinase (MMP) mRNA levels. Results: In SSR exposed unprotected skin sites, we observed melanization and changes in the skin hydration and microtopography. The epidermis revealed a significant increase in stratum corneum and stratum granulosum thickness. In the dermis, an enhanced expression of tenascin and a reduced expression of type I pro-collagen were evidenced just below the dermal epidermal junction. Although we were unable to visualize any change in elastic fibers in exposed buttock skin, a slightly increased deposition of lysozyme and alpha 1 antitrypsin on these fibers was observed using immunofluorescence techniques. Furthermore, types I and III collagen mRNA were slightly increased and a significant enhancement (up to 2.8-fold) of MMP-2 mRNA level was observed. The daily use cream was shown to prevent all these biological changes. Conclusion: Our results show in vivo that an appropriate full-UV spectrum product significantly reduces the solar-UV-induced skin damage, demonstrating the benefit of daily photoprotection. [source]