Ingredients designed to afford sun protection are subject to worldwide legislation, which unfortunately is not helpful for progress towards new ultraviolet (UV) absorbers. In North America eight OTC sunscreen ingredients have been submitted to the FDA through the time and extant (TEA) process for review and approval but, at present, none of these reviews have been completed. It is not only the FDA that is delaying improved sunscreens; European manufacturers are still waiting approval for nano zinc oxide.
With no new UV absorbers to play with, formulators and their ingredient suppliers continue to look at ways of enhancing the efficacy of those that are allowed and at means of mitigating the deleterious effects of sunlight to human skin. These, in addition to sunless tanning, will be the focus of this article.
One material that does have (almost) worldwide approval for use at up to 25% by weight of the total composition is nano sized titanium dioxide (TiO2). Approval in the EU is still not confirmed despite Opinion SCCS/1516/13, which declared nano TiO2 applied topically as UV filter is safe at a maximum use concentration of 25% in cosmetics, provided the material is 99.5% pure TiO2, that it is predominantly in its rutile form with a maximum content of 15% anatase TiO2, and that it is photostable in formulations and has low photocatalytic activity.
Parsol TX from DSM claims greater than 99.5% purity in the rutile form and therefore meets all the criteria required in the above listing, and it is easy to disperse in the oil phase of emulsions due to its highly hydrophobic surface treatment.