All in all, Titanium Dioxide is a famous sunscreen agent and for good reason, it gives broad spectrum UV protection (best at UVB and UVA II), it's highly stable, and it has a good safety profile. It's definitely one of the best UV-filter agents we have today, especially in the US where new-generation Tinosorb filters are not (yet) approved. 

2. Barite calcination method A solution of barium sulfide is prepared. The sulfuric acid and zinc oxide are reacted, purified by adding potassium permanganate and zinc powder, and compressed to obtain a zinc sulfate solution. Then, the prepared barium sulfide solution is mixed and subjected to a metathesis reaction to obtain a mixture of zinc sulfide and barium sulfate, and then the precipitate is subjected to pressure filtration, calcination, wet grinding, drying, and pulverization to obtain a zinc white product.

Duan et al. administered 125 mg/kg BW or 250 mg/kg BW of anatase TiO₂ (5 nm) intragastrically to mice continuously for 30 days. The exposed mice lost body weight, whereas the relative liver, kidney, spleen and thymus weights increased. Particles seriously affected the haemostasis of the blood and the immune system. The decrease in the immune response could be the result of damage to the spleen, which is the largest immune organ in animals and plays an important role in the immune response. Powel et al. demonstrated that TiO₂ NPs may trigger immune reactions of the intestine after oral intake. They showed that TiO₂ NPs conjugated with bacterial lipopolysaccharide, but not TiO₂ NPs or lipopolysaccharide alone, trigger the immune response in human peripheral blood mononuclear cells and in isolated intestinal tissue. This indicates that TiO₂ NPs may be important mediators in overcoming normal gut-cell hyporesponsiveness to endogenous luminal molecules, which may be particularly relevant to patients with inflammatory bowel disease, which is characterized by an abnormal intestinal permeability.

EU ban on titanium dioxide