In a recent issue of the peer-reviewed journal, International Journal of Cosmetic Science, the authors reported the findings of a study conducted with Synoxyl® HSS. Results of this study shows that Synoxyl® HSS is an excellent photostabilizer of Avobenzone in sunscreen formulations and the performance is at least equal if not better than the currently available photostabilizers and also provides a 50% in-vivo SPF boosting. The ability of Synoxyl® HSS to stabilize avobenzone under ultraviolet (UV) light exposure was shown both in formulated products and in solution. A comparative stability study incorporating various combinations of avobenzone, Synoxyl® HSS (vs. three commercial photostabilizers) and UVB sunscreens clearly showed Synoxyl® HSS to be a very effective stabilizer. The photostabilizing effect of Synoxyl® HSS arises from triplet-state energy transfer from avobenzone to Synoxyl® HSS and through light-induced reactions that preserve the main chromophores. Interestingly, a 50% in vivo SPF boosting was observed when Synoxyl® HSS was used with organic and inorganic sunscreens when alone it has no contribution to SPF. Synoxyl® HSS-containing sunscreen formulations clearly showed a critical wavelength of well over 370 nm and can thus be categorized as broad-spectrum sunscreens. The optical properties of Synoxyl® HSS were estimated experimentally and supported by time-dependent density functional theory (TD-DFT) calculations.
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3-(3,4,5-Trimethoxybenzylidene)-2,4-pentanedione: Design of a novel photostabilizer with in vivo SPF boosting properties and its use in developing broad-spectrum sunscreen formulations, RK Chaudhuri, MA Ollengo, P Singh and BS Martincigh, Version of Record online: International J of Cosmetic Science, 29 JUN 2016 | DOI: 10.1111/ics.12344