Infrared photoprotection properties of cosmetic products: correlation between measurement of the anti-erythemic effect in vivo in man and the infrared reflection power in vitro.
Summary Measurements were carried out on 19 commercial cosmetic samples. Initially, their anti-infrared properties were quantified, in vivo, on healthy volunteers, by measuring variations in the Colorimetric Erythema Index DeltaCEI, before and after application of a normalized quantity of product. Subsequently, the physico-chemical response of the product was tested in vitro by measuring the infrared reflection coefficient DeltaIR at 800 nm. The correlation established between these two parameters enables products to be ranked in three categories. A good correlation was demonstrated between reflective power (DeltaIR) and anti-erythemic properties (-DeltaCEI) of the products in the first two groups. A qualitative examination of the diffraction of X-rays confirms the presence of titanium dioxide, TiO(2) rutile, in most products with high IR protection properties whereas TiO(2) anatase was detected in a sample with no IR reflection properties.
Violin
L
L
Laboratoire Dermscan, Centre d'Entreprise et d'Innovation, BP 2132, 69603 Villeurbanne Cedex.
Girard
F
F
Girard
P
P
Meille
J P
JP
Petit-Ramel
M
M