Excipient (pharmacologically inactive substance)
What is it?
Titanium oxide is a naturally occurring mineral used as a bright white pigment for paint, in the food industry as a coloring, in sunscreens and cosmetics, and in other industrial uses. After processing, it is exists as white, powdery solid. Titanium oxide has excellent ultraviolet (UV) resistant qualities and acts as a UV absorbent.
In the pharmaceutical industry, titanium oxide is used in most sunscreens to block UVA and UVB rays, similar to zinc oxide. It is also commonly used as pigment for pharmaceutical products such as gelatin capsules, tablet coatings and syrups. In the cosmetics industry, it is used in toothpaste, lipsticks, creams, ointments and powders. It can be used as an opacifier to make pigments opaque.
The FDA has approved the safety of titanium oxide for use as a colorant in food, drugs and cosmetics, including sunscreens. However, controversy exists as to the safety of titanium oxide nanoparticles used in the cosmetics industry, for example in sunscreens. Titanium and zinc oxides may be made into the nanoparticle size (0.2-100 nanometers) to reduce the white appearance when applied topically, but retain the UV blocking properties. Recent studies suggest titanium oxide nanoparticles may be toxic, although further research is needed.
 Dave RH. Overview of pharmaceutical excipients used in tablets and capsules. Drug Topics (online). Advanstar. 10/24/2008 http://drugtopics.modernmedicine.com/drugtopics/article/articleDetail.jsp?id=561047. Accessed 08/19/2011
 Biello D. Do nanoparticles and sunscreens mix? Scientific American (online). August 20, 2007; http://www.scientificamerican.com/article.cfm?id=do-nanoparticles-and-sunscreen-mix. Accessed 9/8/2011