Oxybenzone

(USAN, rINN)
Oxybenzone Chemical formula
Synonyms: Benzofenon-3; Benzophenone-3; Oxibenzona; Oxybenzonum. 2-Hydroxy-4-methoxybenzophenone.
Cyrillic synonym: Оксибензон.

💊 Chemical information

Chemical formula: C14H12O3 = 228.2.
CAS — 131-57-7.

Pharmacopoeias.

In US.

USP 31

(Oxybenzone). A pale yellow powder. Practically insoluble in water; freely soluble in alcohol and in toluene. Store in airtight containers. Protect from light.

💊 Profile

Oxybenzone is a substituted benzophenone used topically as a sunscreen. Benzophenones effectively absorb light throughout the UVB range (wavelengths 290 to 320 nm) and also absorb some UVA light with wavelengths of 320 to about 360 nm and some UVC light with wavelengths of about 250 to 290 nm. Benzophenones may therefore be used to prevent sunburn and may also provide some protection against drug-related or other photosensitivity reactions associated with UVA light; in practice they are usually combined with a sunscreen from another group. Photocontact allergic dermatitis can be caused by topical application of benzophenone sunscreens. Oxybenzone is widely used and often found to be a photo-allergen in patients with these reactions. Contact allergy reactions occur less frequently.

Hypersensitivity.

Chemical sunscreens are known to cause photosensitivity and contact allergy reactions. Oxybenzone is widely used and reported to be the sunscreen photo-allergen most commonly detected in photopatch testing.1,2 In a group of 5800 patients with suspected allergic contact dermatitis who were tested for contact allergens,3 a positive reaction to oxybenzone was recorded in 0.6%. There have also been rare reports of severe allergic reactions to oxybenzone including anaphylaxis; sensitivity was confirmed by patch testing.4,5 A history of atopy may predispose patients to such reactions.
1. Berne B, Ros A-M. 7 years experience of photopatch testing with sunscreen allergens in Sweden. Contact Dermatitis 1998; 38: 61–4
2. Bryden AM, et al. Photopatch testing of 1155 patients: results of the U.K. multicentre photopatch study group. Br J Dermatol 2006; 155: 737–47.
3. Marks JG, et al. North American Contact Dermatitis Group patch-test results, 1998 to 2000. Am J Contact Dermat 2003; 14: 59–62
4. Emonet S, et al. Anaphylaxis to oxybenzone, a frequent constituent of sunscreens. J Allergy Clin Immunol 2001; 107: 556–7
5. Yesudian PD, King CM. Severe contact urticaria and anaphylaxis from benzophenone-3 (2-hydroxy 4-methoxy benzophenone). Contact Dermatitis 2002; 46: 55–6.

💊 Preparations

USP 31: Dioxybenzone and Oxybenzone Cream. Arg.: Biorevit Labial; Lelco; Braz.: Solaquin.
Published January 05, 2019.