BB creams and their photoprotective effect.

BB creams appeared on the market quite recently. These creams, which give a perfect complexion by covering up the skin's blemishes, have a photoprotective effect in the majority of cases. An SPF value ranging from 10 to 45 concerning the products we tested is displayed on the packaging. The 21 commercially-available BB creams were tested to assess their efficacy (determination of the SPF) and their photostability (determination of their efficacy after UV irradiation). It was shown that 70% of the products tested have an SPF determined in vitro by us which matches the SPF displayed on the product. For the remaining 30%, it can be seen that products have SPF values of between 2 and 10 times lower than those indicated on the products. It can also be noted that there is a large disparity in terms of photostability since, under the same experimental conditions, however, some products only lose 5% of their photoprotective efficacy, whereas others lose 60%.

Comparative evaluation of different co-antioxidants on the photochemical- and functional-stability of epigallocatechin-3-gallate in topical creams exposed to simulated sunlight.

The catechin (-)-epigallocatechin-3-gallate (EGCG) exhibits high antioxidant activity and it has been reported to provide protection of the skin against damage induced by solar UV radiation. However, EGCG is highly unstable under sunlight. The present study aimed to compare the effectiveness of the co-antioxidant agents vitamin E, butylated hydroxytoluene, vitamin C and a-lipoic acid for their potential to protect the catechin from photochemical degradation. Model creams (oil-in-water emulsions) containing EGCG (1%, w/w) alone or combined with equimolar concentrations of co-antioxidant were exposed to a solar simulator at an irradiance corresponding to natural sunlight. Photodegradation was evaluated by HPLC-UV and HPLC-ESI-MS/MS. Addition of the co-antioxidants vitamin C and a-lipoic acid to the formulation significantly reduced the light-induced decomposition of EGCG from 76.9 ± 4.6% to 20.4 ± 2.7% and 12.6 ± 1.6%, respectively. Conversely, butylated hydroxytoluene had no effect (EGCG loss, 78.1 ± 4.6%) and vitamin E enhanced the EGCG photolysis to 84.5 ± 3.4%. The functional stability of the catechin in the creams exposed to the solar simulator was also evaluated by measuring the in vitro antioxidant activity. Following irradiation, the reduction of the EGCG formulation antioxidant power was lower (21.8%) than the extent of degradation (76.9%), suggesting the formation of photoproducts with antioxidant properties. The influence of the examined co-antioxidants on the functional stability of the catechin under simulated sunlight paralleled that measured for the EGCG photodecomposition, a-lipoic acid exerting the greatest stabilising effect (antioxidant activity decrease, 1.4%). These results demonstrated that a-lipoic acid is an effective co-antioxidant agent for the stabilization of EGCG in dermatological products for skin photoprotection.