Oxybenzone
Names | |
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Preferred IUPAC name
(2-Hydroxy-4-methoxyphenyl)(phenyl)methanone | |
Other names
Oxybenzone
Benzophenone-3 2-Hydroxy-4-methoxybenzophenone | |
Identifiers | |
3D model (
JSmol ) |
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ChEBI | |
ChEMBL | |
ChemSpider | |
DrugBank | |
ECHA InfoCard
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100.004.575 |
KEGG | |
PubChem CID
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
C14H12O3 | |
Molar mass | 228.247 g·mol−1 |
Density | 1.20 g cm−3[2] |
Melting point | 62 to 65 °C (144 to 149 °F; 335 to 338 K) |
Boiling point | 224 to 227 °C (435 to 441 °F; 497 to 500 K) |
Acidity (pKa) | 7.6 (H2O)[3] |
Hazards[2] | |
NFPA 704 (fire diamond) | |
Flash point | 140.5 °C (284.9 °F; 413.6 K) |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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>12800 mg/kg (oral in rats) |
Pharmacology | |
Legal status |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Oxybenzone or benzophenone-3 or BP-3 (
The use of oxybenzone as sunscreen ingredient is currently under scrutiny by the scientific community due to controversies about its environmental impact and safety profile (see section below).[6] As a result, sunscreens containing oxybenzone have been banned from sale in Hawaii,[7] Palau,[8] and Thailand.[9]
Structure and electronic structure
Being a
Production
Oxybenzone is produced by
Uses
Oxybenzone is used in plastics as an ultraviolet light absorber and stabilizer. Despite its photoprotective qualities, much controversy surrounds oxybenzone because of its possible hormonal and photoallergenic effects, leading many countries to regulate its use.
Sunscreen
Oxybenzone provides a broad-spectrum ultraviolet coverage which includes
Due to safety concerns, the percentage of sunscreen products on the market containing oxybenzone in the USA dropped to 13% in 2023 from 60% in 2019.[16] Some brands market their sunscreens as "oxybenzone free"[17] due to the negative perception of benzophenones.
Safety
In vivo studies
The incidence of oxybenzone causing photoallergy is extremely uncommon,
In a 2008 study of participants ages 6 and up, oxybenzone was detected in 96.8% of urine samples.[24] Humans can absorb anywhere from 0.4% to 8.7% of oxybenzone after one topical application of sunscreen, as measured in urine excretions. This number can increase after multiple applications over the same period of time.[25] Because oxybenzone is the least lipophilic of the three most common UV filters, it is the least likely to end up trapped in the stratum corneum and the most likely to be absorbed and metabolized.[26]
When applied topically, UV filters, such as oxybenzone, are absorbed through the skin, metabolized, and excreted primarily through the urine.[27] The method of biotransformation, the process by which a foreign compound is chemically transformed to form a metabolite, was determined by Okereke and colleagues through oral and dermal administration of oxybenzone to rats. The scientists analyzed blood, urine, feces, and tissue samples and found three metabolites: 2,4-dihydroxybenzophenone (DHB), 2,2-dihydroxy-4-methoxybenzophenone (DHMB) and 2,3,4-trihydroxybenzophenone (THB).[28][29] To form DHB the methoxy functional group undergoes O-dealkylation; to form THB the same ring is hydroxylated.[27] Ring B in oxybenzone is hydroxylated to form DHMB.[27]
A study done in 2004 measured the levels of oxybenzone and its metabolites in urine. After topical application to human volunteers, results revealed that up to 1% of the applied dose was found in the urine.[30] The major metabolite detected was DHB and very small amounts of THB were found.[30] By utilizing the Ames test in Salmonella typhimurium strains, DHB was determined to be nonmutagenic.[31] In 2019, the U.S. Food and Drug Administration (FDA) noted in their recommendations for future study that, "While research indicates that some topical drugs can be absorbed into the body through the skin, this does not mean these drugs are unsafe."[32] Oxybenzone can be found in some plants.[33][34]
Environmental effects
Studies have shown possible links between oxybenzone exposure and mortality in developing coral, coral bleaching, and genetic damage to coral and marine life.[35][36][37][38][39][40] However, some of these studies have been criticised for not having control groups or representing real-world conditions.[41][42][43][44] Nevertheless, these have led to the ban of oxybenzone-containing sunscreen in many areas[45] such as Palau,[46] Hawaii,[7] nature reserves in Mexico, Bonaire, the Marshall Islands, the United States Virgin Islands, Thailand's marine natural parks,[47] the Northern Mariana Islands,[48] and Aruba.[49]
Health and environmental regulation
Aruba
Aruba banned the use of oxybenzone in sunscreens due to environmental concerns in 2019.[49]
Australia
As of 2023, the maximum concentration of oxybenzone in a sunscreen cannot exceed 10% according to the TGA (Therapeutic Goods Administration).[50]
Bonaire
As of 2019 Bonaire banned oxybenzone due to coral toxicity concerns, with regards to coral larvae[51]
Canada
Revised as of 2012, Health Canada allows oxybenzone for cosmetic use up to 6%.[52]
European Union
The
Japan
Revised as of 2001, the
Mexico
Nature Reserves across Mexico have banned the usage of sunscreens containing Oxybenzone[57]
Palau
The Palau government has signed a law that restricts the sale and use of sunscreen and skincare products that contain oxybenzone, and nine other chemicals. The ban came into force in 2020.[58][59]
Sweden
The Swedish Research Council has determined that sunscreens with oxybenzone are unsuitable for use in young children, because children under the age of two years have not fully developed the enzymes that are believed to break it down. No regulations have come of this study yet.[13]
Thailand
Thailand has prohibited sunscreens containing chemicals harmful to corals, including oxybenzone, in all its marine national parks. This decision was driven by evidence highlighting the detrimental effects of certain sunscreen ingredients on coral larvae, reproduction, and inducing reef bleaching. Violators face fines up to 100,000 baht (£2,100), although enforcement methods remain unspecified.[60]
United States
In 2021 the U.S. FDA changed their classification of oxybenzone and no longer regard it as GRASE (Generally Recognised As Safe and Effective)[61] due to the lack of safety data to support the classification.
The Hawaii State Legislature has legislated oxybenzone as illegal for use in sunscreens and personal care products since 2021 due to its environmental effects, such as mortality in developing coral, coral bleaching, genetic damage to coral, and other marine organisms.[7][62]
References
- ^ Merck Index, 11th Edition, 6907
- ^ a b 131-57-7 at commonchemistry.org
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- ^ "Oxybenzone - Substance Information - ECHA". echa.europa.eu. Retrieved 2019-05-01.
- ^ "Benzophenone-3 (BP-3) Factsheet | National Biomonitoring Program | CDC". www.cdc.gov. 2019-05-24. Retrieved 2019-05-29.
- ^ "Oxybenzone Offers Sun Protection—At a Cost". Byrdie.
- ^ a b c Folley A (2 May 2018). "Hawaii lawmakers approve ban on sunscreens with chemicals harmful to coral reefs". The Hill. Retrieved 2 May 2018.
- ^ "Palau is first country to ban 'reef toxic' sun cream". January 1, 2020 – via www.bbc.com.
- ^ "Thailand bans coral-damaging sunscreens in marine parks". August 4, 2021 – via www.bbc.com.
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- ^ a b c d e "Hazardous Substances Data Bank". 2-HYDROXY-4-METHOXYBENZOPHENONE. National Library of Medicine (US), Division of Specialized Information Services. Retrieved 9 March 2014.
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- ^ S2CID 29173997.
- ^ Edney, Anna (2023-05-24). "There's Still Scary Stuff in Sunscreen". www.bloomberg.com. Retrieved 2023-08-15.
- ^ Slijkerman, Diana; Bol, Sharon (May 2018). "UV filter pollution Bonaire by tourism - Lac Bay monitoring and survey results 2017 - Research Report C023/18". Wageningen University.
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- ^ "Hazardous Substances Data Bank". 2,4-Dihydroxybenzophenone. National Library of Medicine (US), Division of Specialized Information Services. Retrieved 19 April 2014.
- ^ Office of the Commissioner (2019-05-09). "FDA finalizes recommendations for studying absorption of active ingredients in topically-applied OTC monograph drugs". FDA.
- ^ "Benzophenone-3 (BP-3) Factsheet". www.cdc.gov. 2017-12-01. Retrieved 2019-05-01.
- ^ "Benzophenone-3 (BP-3) Factsheet | National Biomonitoring Program | CDC". www.cdc.gov. 2019-05-24. Retrieved 2019-05-29.
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- ^ Hughes T. "There's insufficient evidence your sunscreen harms coral reefs".
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- ^ "PubPeer criticism of Downs, et al".
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- ^ McGrath M (November 2018). "Coral: Palau to ban sunscreen products to protect reefs". BBC News. BBC. Retrieved 2020-01-01.
- ^ "Thailand bans coral-damaging sunscreens". France 24. 2021-08-04. Retrieved 2022-11-02.
- ^ Torres, Governor Ralph (April 2020). "COMMONWEAlTH of the NORTHERN l\fARlANA ISLANDS - OFFICE OF THE GOVERNOR" (PDF). Commonwealth Law Revision Commission.
- ^ a b Overheid, Aruba (2019-11-21). "Single use plastic, the use of Styrofoam and Oxybenzone prohibited!". www.government.aw. Retrieved 2022-11-02.
- ^ "Active ingredients currently restricted for use in therapeutic sunscreens" (PDF). Australian Government: TGA, ARGS, Department of Health and Aged Care. May 2023. p. 40.
- ^ Stephanie Pappas (2018-05-17). "Another Tropical Paradise Enacts a Sunscreen Ban". livescience.com. Retrieved 2023-08-18.
- ^ "Guidance Document Sunscreen Monograph". Health Canada. 2012-12-03. Retrieved 9 March 2014.
- ^ "Endocrine Disruptors: from Scientific Evidence to Human Health Protection" (PDF). European Parliament. European Parliament - Policy Department for Citizens' Rights and Constitutional Affairs - Directorate General for Internal Policies of the Union PE 608.866. March 2019.
- ^ Aguirre C. "Shedding Light on Sun Safety – Part Two". The International Dermal Institute. Archived from the original on 19 May 2014. Retrieved 9 March 2014.
- ^ "COMMISSION REGULATION (EU) 2022/1176".
- ^ "Standards for Cosmetics" (PDF). Ministry of Health and Welfare Notification No.331 of 2000. Japanese Government. Retrieved 9 March 2014.
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- ^ McGrath M (November 2018). "Palau to ban sunscreen to save coral reefs". BBC News.
- ^ "The Republic of Palau Adopts the World's Strictest National Sunscreen Standard – PalauGov.pw". Retrieved 2023-08-18.
- ^ "Thailand bans coral-damaging sunscreens in marine parks". BBC News. 2021-08-04. Retrieved 2023-08-18.
- ^ Research, Center for Drug Evaluation and (2021-11-16). "Questions and Answers: FDA posts deemed final order and proposed order for over-the-counter sunscreen". FDA.
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- ^ Filosa G (February 5, 2019). "Key West bans the sale of sunscreens that hurt coral reefs in the Keys". Miami Herald. Retrieved 6 February 2019.
- ^ "SB 172: Florida Drug and Cosmetic Act". The Florida Senate. Retrieved 2020-11-10.