The global Lithopone market is highly consolidated and a major bulk of Lithopone is produced in China. Some of the major Lithopone producers include Anhui Union Titanium Enterprise Co. Ltd., Fengchen Group Co. Ltd., Henan Premtec Enterprise Corporation, Langfang Pairs Horses Chemical Co. Ltd., Natural Pigments Inc., Noah Technologies Corporation, Titanos Group, VB Technochemicals SA, Venator Materials PLC, and ZhengZhou Sino Chemical Products Co. Ltd.
The conjugation of vitamin C to the P25TiO2NPs was confirmed by UV-visible spectroscopy of lyophilized vitaminC@P25TiO2NPs suspensions. The typical absorbance peak of ascorbic acid at 265 nm was found. However, no further characterization was done because they did not show the expected protective effect against the photo-induced cell damage (Fig. 3).
Traditionally, UV-filters are categorized as either chemical or physical. The big difference is supposed to be that chemical agents absorb UV-light while physical agents reflect it like a bunch of mini umbrellas on top of the skin. While this categorization is easy and logical it turns out it's not true. A recent, 2016 study shows that inorganic sunscreens work mostly by absorption, just like chemical filters, and only a little bit by reflection (they do reflect the light in the visible spectrum, but mostly absorb in the UV spectrum).