Light stabilizers physical

Mineral pigments which attenuate UV rays and, if necessary, also visible light by reflection, scattering and/or absorption and thus provide light protection for the skin. These include:

• Kaolin
• Magnesium silicate
• Magnesium oxide
• Titanium dioxide
• Iron oxide
• Zinc oxide

Physical sunscreens act by protective effects of macro pigments such as titanium oxide, zinc oxide, iron oxide, kaolin, talcum and are based on deflection of sunrays by reflection, scattering and absorption.

Concealing light protection pastes are highly effective but are sometimes not tolerated due to the whitening effect and their high "pasty" consistency (difficult to spread on the skin). They are accepted by patients with severe forms of light dematoses.

The more recent development of micro pigments (reduction of particle size to 1-100nm) with avoidance of the whitening effect at high efficacy (also in the UV range) is to be regarded as a great progress. By reducing the particle size, the reflection and scattering power in visible light is eliminated. The whitening effect no longer occurs. The light protection in the UV range is maintained. Ultrafine titanium dioxide protects mainly in the UV-B range, ultrafine zinc oxide mainly in the UV-A range. The absorption of the nanoparticles through the skin has not been conclusively clarified.

Micropigment-containing preparations are particularly suitable for the following indications:

• Presence of a high or pathological sensitivity to sunlight
• Protection of particularly UV-stressed skin areas such as lips
• Protection of pigment-free or low-pigment skin areas
• Protection of heavily pigmented or slightly darkened areas such as age spots, chloasma/melasma or freckles
• Protection of the child's skin.

1. Nagelreiter C et al (2015) Size analysis of nanoparticles extracted from W/O emulsions. Int J Pharm 488:29-32.
2. Nigro M et al (20159 n-TiO2 and CdCl2 co-exposure to titanium dioxide nanoparticles and cadmium: Genomic, DNA and chromosomal damage evaluation in the marine fish European sea bass (Dicentrarchus labrax). Aquat Toxicol 168:72-77.
3. Oliveira CA et al (2016) Cutaneous biocompatible rutin-loaded gelatin-based nanoparticles increase the SPF of the association of UVA and UVB filters. Eur J Pharm Sci 81:1-9.
4. Wolf P (2015) Sun protection. In: E.v. Stebut (Ed.) Traveler dermatoses. Springer Publishing House Berlin-Heidelberg p. 300-303