A short review of alternative ingredients and technologies of inorganic UV filters

Abstract

Background The growing need to use sunscreens is a concrete reality, and it is associated with the increase in the population's awareness of the ultraviolet (UV) radiation damage. Inorganic UV filters promote the formation of particles/pigments film over the skin surface, reflecting, dispersing, and absorbing the radiation. Investigations of this class of filters demonstrate the emergence of alternative ingredients and new technologies. Aims and Methods In this review, we presented potential candidates for alternative UV inorganic filters, such as hydroxyapatite, cerium dioxide, and hydrotalcite. Results Specialized literature identified hydroxyapatite and cerium dioxide as actives with good performances, with a broad spectrum of absorption against UV radiation. Both of them were considered safe against degradation and skin erythema formation. Inorganic compounds as an alternative to circumvent degradation problems of organic UV filters containing PABA were also analyzed, with hydrotalcite having a good performance in improving the performance of classic ingredients, bypassing photoinstability, and improving safety, in addition to preventing skin irritability. Conclusion Further investigations of these ingredients and interactions with sunscreen formulations are necessary to overall explore their safety and efficacy, encouraging future researches for more inorganic UV filters.

Effect of Fish Bone Bioactive Peptides on Oxidative, Inflammatory and Pigmentation Processes Triggered by UVB Irradiation in Skin Cells

“…A sunscreen provides protection on the entire UV domain (200–400 nm) due to constituent organic and inorganic filters that absorb and reflect, respectively, the UV radiation [ 37 , 38 ]. Plant extracts and, in particular, polyphenolic compounds, such as rutin, ferulic acid and caffeine were clinically tested as natural UV filters and provided enhanced photoprotection to traditional sunscreens, delaying erythema through different mechanisms of antioxidant and anti-inflammatory action [ 38 ].…”

Amorphous and crystalline cerium(iv) phosphates: biocompatible ROS-scavenging sunscreens

“…47–49 For example, the use of calcium phosphates in sunscreens has been reported. 29,50–53 In turn, layered titanium phosphate Ti 2 O 2 H(PO 4 )[(NH 4 ) 2 PO 4 ] 2 pigment has also shown UV protection ability, as well as moisture retention, and is particularly well suited for cosmetic applications. 54…”

“…21 A number of inorganic compounds are now considered as alternatives to TiO 2 and ZnO as UV-filters, primarily nanocrystalline cerium dioxide (CeO 2 ), which also effectively absorbs ultraviolet radiation, possesses high biocompatibility and is capable of inactivating reactive oxygen species, acting as an inorganic antioxidant or nanozyme. [22][23][24][25][26][27][28][29] At the same time, the possible use of alternative UV-filters (including ceria) is rarely discussed, in view of all the abovementioned unresolved issues.…”

“…[47][48][49] For example, the use of calcium phosphates in sunscreens has been reported. 29,[50][51][52][53] In turn, layered titanium phosphate Ti 2 O 2 H(PO 4 )[(NH 4 ) 2 PO 4 ] 2 pigment has also shown UV protection ability, as well as moisture retention, and is particularly well suited for cosmetic applications. 54 In their study of UV-protection property of cerium(III) phosphate, Lima and Serra 55 showed that the absorption coefficient of UV radiation in the 280-400 nm range in nanocrystalline CePO 4 is higher than that of CeO 2 or TiO 2 , while CePO 4 has lower photocatalytic activity.…”

The Use of Calcium Phosphates in Cosmetics, State of the Art and Future Perspectives

“…The requisites of the ideal sunscreen should be broad protection over UVA and UVB, nontoxicity, no photocatalytic effects, and environmental safety. In recent years, HA has been proposed as a safe sunscreen ingredient, and the interest in CaPs for this application is growing [195,196]. In the literature, there are several examples that report the preparation of HA as a safe inorganic sunscreen ingredient to replace ZnO and TiO 2 [197][198][199][200][201][202][203][204][205][206][207][208][209][210][211].…”