The vitaminC@P25TiO₂NPs, on the other side, did not have any effect on cell protection against ROS. This might be due to the fact that vitamin C, a well-known scavenger of ROS, could behave as prooxidant and even promote ROS and lipid peroxidation [39]. It was recently described that at small concentrations of vitamin C, the prooxidant effects dominate; while in large concentrations the antioxidant ones predominate [40]. The effect also depends on the cell state and the interaction of vitamin C with light. In this case, ascorbic acid may act as an antenna to harvest visible light when conjugated to P25TiO₂NPs. Indeed, it was previously found that this combination (in some ratios) could have an improved photocatalytic activity, possibly due to a red shift in its light absorbance [41]. Further studies on vitaminC@P25TiO₂NPs were not conducted, because of the poor antioxidant capacity [42].

One of the key challenges facing TiO2 industry suppliers is the fluctuation of raw material prices. The production of TiO2 requires raw materials such as ilmenite or rutile, which are subject to market price volatility. Suppliers must carefully monitor these fluctuations and adjust their production processes accordingly to ensure profitability.

With 30% of the world's lithopone factories located in China, the country has become a major player in the global lithopone market. Chinese manufacturers are able to produce lithopone at a competitive price, making it an attractive option for companies looking to reduce their production costs. In addition, China's large production capacity ensures a steady and reliable supply of lithopone to markets around the world.