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Topical and Systemic Photoprotection of Human Skin Against Solar Radiation
Published in Henry W. Lim, Nicholas A. Soter, Clinical Photomedicine, 2018
To minimize the harmful cumulative effects of UVA radiation, certain UVA-absorbing chemicals are added to the UVB-absorbing sunscreens. These include certain benzophenones (oxybenzone, dioxybenzone, sulisobenzone); dibenzoyl methanes (e.g., Parsol 1789, Eusolex-8020, Parsol DAM); and certain physical sunscreen agents (e.g., zinc oxide or titanium dioxide). Parsol 1789 [1-(4-tertbutylphenyl-3-(4-methoxyphenyl) propane-1,3-dione] has received FDA approval for use as a UVA blocker in a specific formulation (Photoplex) at a concentration of 3%. Thus, UVA-induced increased pigmentation and psoralen-induced phototoxic reactions (8-methoxypsoralen and 4,5’,8-trimethylpsoralen-induced phototoxic reactions) caused by topical application or oral ingestion of psorlen and subsequent exposure to 320–380 nm radiation can be minimized by sunscreens containing certain benzophenone derivatives as well as by Parsol 1789 (3,5,13,19,25,26). Drug-induced phototoxic reactions (e.g., chlorothiazides, demethylchlortetracycline, nalidixic acid, amiodarone, and various psoralens) can be prevented by the use of topical sunscreens containing UVA-absorbing chemicals.
Sunscreens
Published in Dimitris Rigopoulos, Alexander C. Katoulis, Hyperpigmentation, 2017
Benzophenones are good UVA absorbers, although their effectiveness is primarily in the UVA2 range. Oxybenzone is the most commonly used agent in this group and actually affords both UVB and UVA protection. Sulisobenzone and dioxybenzone have similar protective spectra but are infrequently utilized.
Prospects of topical protection from ultraviolet radiation exposure: a critical review on the juxtaposition of the benefits and risks involved with the use of chemoprotective agents
Published in Journal of Dermatological Treatment, 2018
Nilutpal Sharma Bora, Bhaskar Mazumder, Pronobesh Chattopadhyay
Benzophenones possess good broad-spectrum UVB and UVA protection range. They are intensely photolabile and can undergo oxidation which can interfere with the antioxidant system. Out of the three FDA-approved benzophenones; namely oxybenzone, sulisobenzone, and dioxybenzone, oxybenzone is most commonly used, but also has the highest incidence of photoallergic contact dermatitis (64). Meradimate is another benzophenone which used in conjugation with other agents to enhance UVA protection (67). Avobenzone (butyl methoxydibenzoylmethane) is a potent UVA filter and was the first FDA approved organic agent which is able to effectively filter UVA (340–400 nm). However, avobenzone is highly photolabile; and loses 50–60% of its potency within 1 h of sun exposure (68,69). Avobenzone also affects the stability of other active sunscreen ingredients, like octocrylene and bemotrizinol and much research has been done to stabilize formulations containg these ingredients (70–72).