New developments in sunscreens

Abstract

Topical sunscreen application is one of the most important photoprotection tool to prevent sun damaging effects in human skin at the short and long term. Although its efficacy and cosmeticity have significantly improved in recent years, a better understanding of the biological and clinical effects of longer wavelength radiation, such as long ultraviolet A (UVA I) and blue light, has driven scientists and companies to search for effective and safe filters and substances to protect against these newly identified forms of radiation. New technologies have sought to imbue sunscreen with novel properties, such as the reduction of calorific radiation. Cutaneous penetration by sunscreens can also be reduced using hydrogels or nanocrystals that envelop the filters, or by binding filters to nanocarriers such as alginate microparticles, cyclodextrins, and methacrylate polymers. Finally, researchers have looked to nature as a source of healthier products, such as plant products (e.g., mycosporines, scytonemin, and various flavonoids) and even fungal and bacterial melanin, which could potentially be used as substitutes or enhancers of current filters. Graphical abstract

Sunproofing from within: A deep dive into oral photoprotection strategies in dermatology

“…20,21 High-energy visible radiation (HEVR) or blue light corresponds to a wavelength above 380 nm, which has also been shown to cause hyperpigmentation, free radical production, immunomodulation, DNA damage, and photoaging. 22…”

“…24 Currently, a combination of broad-spectrum filters against UVA and UVB protects the skin against biological effects of UVR such as erythema, and persistent skin pigmentation, especially against wavelengths of 400 nm or more, capable of absorbing some VL. 22 The combination of inorganic filters with organic filters has shown the ability to absorb the UV and visible wave spectrum. Color filters contain a mixture of Fe 2 O 3 and TiO 2 pigments that function by blocking VL, 26 providing a dual function of coverage and reduction of sun-induced pigmentation.…”

“…8 The ideal topical photoprotector should present a combination of filters against UVB and UVA absorption, and a filter against VL and IR. 22 A systemic photoprotective agent would have multiple advantages over a topical one: it would not be affected by external factors such as water, sweat, or rubbing, it distributes evenly, acts for an extended period, protects the entire body surface, is independent of cream properties and the amount applied. 18,28 Supplementing topical photoprotection with diet-reinforcing protection against the harmful effects of sunlight is of great interest.…”

“…51 Polypodum leucotomos protects against damage caused by IR and UV-induced skin damage 6 and VL, primarily due to its antioxidant effects and protection against the immunosuppressive and hyperpigmentation effects caused by HEVR. 22 PL extract is a well-tolerated and safe agent with photoprotective properties, making it potentially a suitable adjunct in combating UVR and VL-induced skin aging. 52 Studies in humans have found evidence that it increases the UV dose required for the immediate darkening of pigment, the MED, and the minimal phototoxic dose.…”

Evaluation of MAA Analogues as Potential Candidates to Increase Photostability in Sunscreen Formulations

“…To avoid UV radiation damaging effects, scientists have develop a series of sunscreen formulations to protect humans from potential UV damage [2], in addition to natural protection [3]. Nowadays, none of the commercially available sunscreen molecules present ideal behavior as a photoprotector, as these molecules should fulfill a long list of requirements [4,5]. These compounds should present, among other features, very large photostability together with broad and intense absorption in the UV region.…”