Characteristics of Common White Pigments

Is Titanium Dioxide Safe?

This article reviews the uses, benefits, and safety of titanium dioxide.

The lack of clear regulations and controls explains that P25TiO₂NPs are still found in many of the commercialized sunscreens in the market. Some of them are coated to reduce the photoactivity of the anatase form, which is known to be responsible for tissue damage, but not enough studies were made on these coated forms. The anatase photoactivity could trigger the production of reactive oxygen species (ROS) generation, as it was stated before. The ROS are chemically reactive species containing oxygen, such as peroxides, superoxide, hydroxyl radical, and singlet oxygen. They are regularly produced in the biological milieu and counterbalanced by physiological antioxidant defense mechanisms. However, an abrupt increase of ROS may result in non-reversible damage to the skin cells. The effects of coated and uncoated P25TiO₂NPs need therefore to be studied, and articles on this topic present different conclusions. [11], [12], [13] Recent literature on this topic found that TiO₂NPs inhalation provokes serious genotoxicity and DNA damage [14], [15], [16], [17]. On the other hand, some studies in rats have reported no significant harm to genetic material [18], [19], [20], [21], [22].

French researchers studied how and where E171 nanoparticles enter the bloodstream, first studying the route through pigs and then in vitro with human buccal cells, for a 2023 study published in the journal Nanotoxicology. The research showed that the nanoparticles absorbed quickly through the mouth and then into the bloodstream, before damaging DNA and hindering cell regeneration.

The committee could not finalize the assessment of some other flavoring agents, requiring further information. JECFA highlighted the importance of receiving complete data submissions from the sponsors for conducting the safety evaluation.

Barium sulphate is typically described as a white, odorless powder. This white coloration is due to its crystalline structure and the arrangement of Ba^2+ and SO₄^2− ions within the compound. The brightness and consistency of this white powder are crucial for its use in various applications. For instance, in the pharmaceutical industry, barium sulphate is used as a radiopaque agent in X-ray imaging of the gastrointestinal tract. In this context, its purity and the absence of color impurities are vital for ensuring accurate imaging results.