In summary, although more human evidence is needed to determine the risks of the mineral, potential titanium dioxide side effects from excessive exposure (especially when inhaled) may include:

Water solubles, %

As mentioned above, these oxide NPs are harmful in part because both anatase and rutile forms are semiconductors and produce ROS. Particularly, P25 kind has band-gap energies estimated of 3.2 and 3.0 eV, equivalent to radiation wavelengths of approximately 388 and 414 nm, respectively. Irradiation at these wavelengths or below produces a separation of charge, resulting in a hole in the valence band and a free electron in the conduction band, due to the electron movement from the valence to conduction bands. These hole–electron pairs generate ROS when they interact with H₂O or O₂ [43,44]. It was described that they can cause an increase in ROS levels after exposure to UV-visible light [45]. The NBT assay in the studied samples showed that bare P25TiO₂NPs produce a large amount of ROS, which is drastically reduced by functionalization with vitamin B2 (Fig. 5). This vitamin, also known as riboflavin, was discovered in 1872 as a yellow fluorescent pigment, [46] but its function as an essential vitamin for humans was established more than sixty years later, and its antioxidant capacity was not studied until the end of the XX century [47,48]. This antioxidant role in cells is partially explained because the glutathione reductase enzyme (GR) requires it for good functionality. This enzyme is the one in charge of the conversion of oxidized glutathione to its reduced form which acts as a powerful inner antioxidant and can quench the ROS [49,50]. The cost of this action is that the glutathione is converted to the oxidized form and needs to be recovered by the GR. Consequently, the cells need more vitamin B2. Another glutathione action is the protection against hydroperoxide. This activity is also mediated by riboflavin. Therefore, local delivery of this vitamin seems to significantly help the cells in their fight to keep the oxidative balance, once they are exposed to high levels of ROS.

Declaration of Competing Interest

Certificate of Analysis (Lithopone B301, Lithopone B311 powder TDS)

A1:

Irradiation panel

Lithopone, C.I. Pigment White 5, is a mixture of inorganic compounds, widely used as a white pigment powder. It is composed of a mixture of barium sulfate and zinc sulfide. These insoluble compounds blend well with organic compounds and confer opacity. It was made popular by the cheap production costs, greater coverage. Related white pigments include titanium dioxide, zinc oxide (zinc white), zinc sulfide, and white lead.

Following the EU’s ban on E171, the FDA told the Guardian that, based on current evidence, titanium dioxide as a food additive is safe.  “The available safety studies do not demonstrate safety concerns connected to the use of titanium dioxide as a color additive.”

The reaction liquid is filtered through plate and frame pressure to obtain lithopone in the form of a filter cake with a moisture content of no more than 45%. It is then roasted in a drying furnace to change the crystal form of lithopone, and is then pickled with sulfuric acid at a temperature of 80°C. Finally, it is washed with water, reinforced with colorants, filtered, dried and ground into powder.

North America

Appearance:

Lithopone 30% has a lower coverage power than titanium dioxide. For this reason, Lithopone 30% can only partially substitute titanium dioxide, between 5 and 40%. 

Titanium dioxide is an inert earth mineral used as a thickening, opacifying, and sunscreen ingredient in cosmetics. It protects skin from UVA and UVB radiation and is considered non-risky in terms of of skin sensitivity. Because it is gentle, titanium dioxide is a great sunscreen active for sensitive, redness-prone skin. It’s great for use around the eyes, as it is highly unlikely to cause stinging.

Lithopone B301, Lithopone B311 powder is widely used in coatings, printing ink, rubber, plastic industry, etc.