Analyst Insight

Production of TiO₂ Pigment

When examining a lithopone pigment pricelist, one might notice that prices can vary significantly between different grades of lithopone. Generally, there are two main types Lithopone 28 and Lithopone 60, with the numbers denoting the percentage of zinc sulfide content. Lithopone 28, with a lower zinc sulfide content, is often more affordable compared to Lithopone 60, which offers superior whiteness and opacity. The choice between these grades depends largely on the specific requirements of the end application.

Even if you’re not familiar with titanium dioxide in makeup, it’s quite likely you’ve seen it in sunscreens, specifically physical formulas. Titanium dioxide is beloved in cosmetics not only for the pigment and coloration it can provide but also for the way it reacts to light.

On absorption of UV light, photo-generated titanium dioxide particles create singlet oxygen, superoxide anions (O2-) and hydroxyl radicals (OH-) that are potent free radicals (1,2). Irradiated particles of titanium dioxide can induce oxidative damage to DNA (2) which can lead to the development of mutant cells and skin cancers (3,4,5,6) and lipid peroxidation of essential functions on the cell membrane (7).

Fig. 8. Selected images of skin stratus treated with P25TiO₂NPs 10% (left) and VitaminB2@P25TiO₂NPs 10% (right) under light, showing no penetration of the nanoparticles (white arrows) beyond the outer stratum corneum.