Drometrizoles trisiloxanes

Drometrizoles Trisiloxanes, a white solid, is a light stabilizer with the molecular formula C24H39N3O3Si3. Drometrizole trisiloxanes, as UV filters, have two absorption peaks, one at 303 nm (UV-B) and a second at 344 nm (UV-A).

The UV absorber is used in maximum 10% concentration in sunscreens as well as in care products with UV protection. Drometrizole trisiloxanes are only slightly absorbed percutaneously and thus have only minor systemic effects (Benech-Kieffer F et al. 2003).

Mexoryl XL®; Ecamsule® (trade name on the American market)

Organic light protection filters are all those UV filters whose effect is not exclusively based on the inorganic, physically active substances titanium dioxide or zinc oxide. Organic, also known as chemical UV filters, are photoactive substances that are able to absorb light quanta in a certain wavelength range (ultraviolet radiation in the range of about 280 to 400 nm = ultraviolet radiation = UVB/UVA spectrum). The absorbed UV is then released as thermal energy without penetrating the skin. In this reversible photoisomerization, the energy of the absorbed photon must correspond to the energy required to lift an electron in the molecule of the filter substance from a lower to a higher orbit. In order to protect over the entire width of the wavelengths relevant to humans from 290 to 400 nm, several chemical filters with different absorption maxima are usually combined. With a suitable combination of organic and physical filters, the content of organic filters can also be reduced with the same UV protection. This is desirable, since especially photounstable organic UV filters can cause phototoxic and photoallergic reactions depending on their concentration in the finished product.

1. Benech-Kieffer F et al (2003) Percutaneous absorption of Mexoryl SX in human volunteers: comparison with in vitro data. Skin Pharmacol Appl Skin Physiol 16: 343-355