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) | |
ChEBI | |
ChEMBL | |
ChemSpider | |
DrugBank | |
ECHA InfoCard | 100.004.575 |
KEGG | |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C14H12O3 | |
Molar mass | 228.247 g·mol−1 |
Appearance | pale yellow crystals |
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) | >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). |
Oxybenzone or benzophenone-3 or BP-3 (trade names Milestab 9, Eusolex 4360, Escalol 567, KAHSCREEN BZ-3) is an organic compound belonging to the class of aromatic ketones known as benzophenones. It takes the form of pale-yellow crystals that are readily soluble in most organic solvents. It is widely used in sunscreen formulations, plastics, toys, furniture finishes, and other products to limit UV degradation. [4] In nature, it can be found in various flowering plants (angiosperms). [5] The compound was first synthesised in Germany by chemists König and Kostanecki in 1906.
The use of oxybenzone as sunscreen ingredient is currently under scrutiny by the scientific community due to controversies about the molecule's 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]
Being a conjugated molecule, oxybenzone absorbs light at lower energies than many aromatic molecules. [10] As in related compounds, the hydroxyl group is hydrogen bonded to the ketone. [11] This interaction contributes to oxybenzone's light-absorption properties. At low temperatures, however, it is possible to observe both the phosphorescence and the triplet-triplet absorption spectrum. At 175 K the triplet lifetime is 24 ns. The short lifetime has been attributed to a fast intramolecular hydrogen transfer between the oxygen of the C=O and the OH. [12]
Oxybenzone is produced by the Friedel-Crafts reaction of benzoyl chloride with 3-methoxyphenol. [13]
Oxybenzone is used in plastics as an ultraviolet light absorber and stabilizer. [13] It is used, along with other benzophenones, in sunscreens, hair sprays, and cosmetics because they help prevent potential damage from sunlight exposure. It is also found, as a stabilizer in concentrations up to 1%, in nail polishes. [13] Oxybenzone can also be used as a photostabilizer for synthetic resins. [13] This substance can leach from food packaging, and is widely used as photo-initiators to activate a chemical that dries ink faster. [14] Despite its photoprotective qualities, much controversy surrounds oxybenzone because of possible negative hormonal and photoallergenic effects, leading many countries to regulate use in sunscreen products.
Oxybenzone provides a broad-spectrum ultraviolet coverage which includes UVB and short-wave UVA rays. As a photoprotective agent, it has an absorption profile spanning from 270 to 350 nm with absorption peaks at 288 and 350 nm. [15]
Due to toxicity and environmental 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 generally negative perception of benzophenones by both the consuming public and scientific researchers.
The incidence of oxybenzone causing skin eruptions is extremely uncommon, [18] however, oxybenzone has been associated with rare allergic reactions triggered by sun exposure. In a study of 82 patients with photoallergic contact dermatitis, just over one quarter showed photoallergic reactions to oxybenzone. [19] Evidence points to oxybenzone having contact allergen effects. [15] [18] Oxybenzone is allegedly the most common allergen found in sunscreens. [20] [21] [22] [23]
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 also occur as a natural product. [33] [34]
Studies have shown possible links between oxybenzone exposure and mortality in coral larvae, coral bleaching, and to genetic damage in marine invertebrates. [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]
Aruba banned the use of oxybenzone in sunscreens due to environmental concerns in 2019. [49]
As of 2023, the maximum concentration of oxybenzone in a sunscreen cannot exceed 10% according to the TGA (Therapeutic Goods Administration). [50]
As of 2019 Bonaire banned oxybenzone due to coral toxicity concerns, with regards to coral larvae [51]
Revised as of 2012, Health Canada allows oxybenzone for cosmetic use up to 6%. [52]
The European Food Safety Authority categorises All the benzophenones, such as oxybenzone, as persistent, bio-accumulative, toxic, and a possible human carcinogen and endocrine disruptor. [53] The Scientific Committee on Consumer Products (SCCP) of the European Commission concluded that it poses a significant risk to consumers as a contact allergenic potential. [54] It is allowed in face, hand, and lip products up to 6%, in body products up to 2.2%, and in other formulations up to 0.5%. [55]
Revised as of 2001, the Ministry of Health, Labour, and Welfare notification allows oxybenzone for cosmetic use up to 5%. [56]
Nature Reserves across Mexico have banned the usage of sunscreens containing Oxybenzone [57]
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]
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 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]
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]
Key West has also banned the sale of sunscreens that contain the ingredients oxybenzone (and octinoxate). The ban was to be effective as of January 1, 2021. [63] However, this legislation was superseded by the Florida State Legislature by Senate Bill 172, [64] which prohibits local governments from regulating over-the-counter proprietary drugs and cosmetics (such as sunscreen containing oxybenzone and octinoxate). The statute became effective July 1, 2020.
Titanium dioxide, also known as titanium(IV) oxide or titania, is the inorganic compound derived from titanium with the chemical formula TiO
2. When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or CI 77891. It is a white solid that is insoluble in water, although mineral forms can appear black. As a pigment, it has a wide range of applications, including paint, sunscreen, and food coloring. When used as a food coloring, it has E number E171. World production in 2014 exceeded 9 million tonnes. It has been estimated that titanium dioxide is used in two-thirds of all pigments, and pigments based on the oxide have been valued at a price of $13.2 billion.
Benzophenone is a naturally occurring organic compound with the formula (C6H5)2CO, generally abbreviated Ph2CO. Benzophenone has been found in some fungi, fruits and plants, including grapes. It is a white solid with a low melting point and rose-like odor that is soluble in organic solvents. Benzophenone is the simplest diaromatic ketone. It is a widely used building block in organic chemistry, being the parent diarylketone.
Sunscreen, also known as sunblock, sun lotion or sun cream, is a photoprotective topical product for the skin that helps protect against sunburn and prevent skin cancer. Sunscreens come as lotions, sprays, gels, foams, sticks, powders and other topical products. Sunscreens are common supplements to clothing, particularly sunglasses, sunhats and special sun protective clothing, and other forms of photoprotection.
Coral bleaching is the process when corals become white due to loss of symbiotic algae and photosynthetic pigments. This loss of pigment can be caused by various stressors, such as changes in temperature, light, or nutrients. Bleaching occurs when coral polyps expel the zooxanthellae that live inside their tissue, causing the coral to turn white. The zooxanthellae are photosynthetic, and as the water temperature rises, they begin to produce reactive oxygen species. This is toxic to the coral, so the coral expels the zooxanthellae. Since the zooxanthellae produce the majority of coral colouration, the coral tissue becomes transparent, revealing the coral skeleton made of calcium carbonate. Most bleached corals appear bright white, but some are blue, yellow, or pink due to pigment proteins in the coral.
Lipophilicity is the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. Such compounds are called lipophilic. Such non-polar solvents are themselves lipophilic, and the adage "like dissolves like" generally holds true. Thus lipophilic substances tend to dissolve in other lipophilic substances, whereas hydrophilic ("water-loving") substances tend to dissolve in water and other hydrophilic substances.
Sunless tanning, also known as UV filled tanning, self tanning, spray tanning, or fake tanning, refers to the effect of a suntan without exposure to the Sun. Sunless tanning involves the use of oral agents (carotenids), or creams, lotions or sprays applied to the skin. Skin-applied products may be skin-reactive agents or temporary bronzers (colorants).
Ecamsule is an organic compound which is added to many sunscreens to filter out UVA rays. It is a benzylidene camphor derivative, many of which are known for their excellent photostability.
Avobenzone is an organic molecule and an oil-soluble ingredient used in sunscreen products to absorb the full spectrum of UVA rays.
Octyl methoxycinnamate or ethylhexyl methoxycinnamate (INCI) or octinoxate (USAN), trade names Eusolex 2292 and Uvinul MC80, is an organic compound that is an ingredient in some sunscreens and lip balms. It is an ester formed from methoxycinnamic acid and 2-ethylhexanol. It is a liquid that is insoluble in water.
Natural skin care uses topical creams and lotions made of ingredients available in nature. Much of the recent literature reviews plant-derived ingredients, which may include herbs, roots, flowers and essential oils, but natural substances in skin care products include animal-derived products such as beeswax, and minerals. These substances may be combined with various carrier agents, preservatives, surfactants, humectants and emulsifiers.
UV filters are compounds, mixtures, or materials that block or absorb ultraviolet (UV) light. One of the major applications of UV filters is their use as sunscreens to protect skin from sunburn and other sun/UV related damage. After the invention of digital cameras changed the field of photography, UV filters have been used to coat glass discs fitted to camera lenses to protect hardware that is sensitive to UV light.
Octocrylene is an organic compound used as an ingredient in sunscreens and cosmetics. It is an ester formed by the Knoevenagel condensation of 2-ethylhexyl cyanoacetate with benzophenone. It is a viscous, oily liquid that is clear and colorless.
Photoprotection is the biochemical process that helps organisms cope with molecular damage caused by sunlight. Plants and other oxygenic phototrophs have developed a suite of photoprotective mechanisms to prevent photoinhibition and oxidative stress caused by excess or fluctuating light conditions. Humans and other animals have also developed photoprotective mechanisms to avoid UV photodamage to the skin, prevent DNA damage, and minimize the downstream effects of oxidative stress.
Skin care or skincare is a range of practices that support skin integrity, enhance its appearance, and relieve skin conditions. They can include nutrition, avoidance of excessive sun exposure, and appropriate use of emollients. Practices that enhance appearance include the use of cosmetics, botulinum, exfoliation, fillers, laser resurfacing, microdermabrasion, peels, retinol therapy, and ultrasonic skin treatment. Skin care is a routine daily procedure in many settings, such as skin that is either too dry or too moist, and prevention of dermatitis and prevention of skin injuries.
Bisoctrizole is a phenolic benzotriazole that is added to sunscreens to absorb UV rays. It is a broad-spectrum ultraviolet radiation absorber, absorbing UVB as well as UVA rays. It also reflects and scatters UV.
Personal care products are consumer products which are applied on various external parts of the body such as skin, hair, nails, lips, external genital and anal areas, as well as teeth and mucous membrane of the oral cavity, in order to make them clean, protect them from harmful germs and keep them in good condition. They promote personal hygiene and overall health, well-being and appearance of those body parts. Toiletries form a narrower category of personal care products which are used for basic hygiene and cleanliness as a part of a daily routine. Cosmetic products, in contrast, are used for personal grooming and beautification. Pharmaceutical products are not considered personal care products.
Coral reef protection is the process of modifying human activities to avoid damage to healthy coral reefs and to help damaged reefs recover. The key strategies used in reef protection include defining measurable goals and introducing active management and community involvement to reduce stressors that damage reef health. One management technique is to create Marine Protected Areas (MPAs) that directly limit human activities such as fishing.
Human activities have substantial impact on coral reefs, contributing to their worldwide decline. Damaging activities encompass coral mining, pollution, overfishing, blast fishing, as well as the excavation of canals and access points to islands and bays. Additional threats comprise disease, destructive fishing practices, and the warming of oceans.[2] Furthermore, the ocean's function as a carbon dioxide sink, alterations in the atmosphere, ultraviolet light, ocean acidification, viral infections, the repercussions of dust storms transporting agents to distant reefs, pollutants, and algal blooms represent some of the factors exerting influence on coral reefs. Importantly, the jeopardy faced by coral reefs extends far beyond coastal regions. The ramifications of climate change, notably global warming, induce an elevation in ocean temperatures that triggers coral bleaching—a potentially lethal phenomenon for coral ecosystems.
The Public Access to Sunscreens Coalition, or PASS Coalition, is a coalition of public health organizations, dermatologists and sunscreen product companies whose mission is to help prevent skin cancer and improve public health by ensuring Americans have access to safe and effective sunscreens and evidence-based education on sun-safe practices. It accomplishes these goals by lobbying for an efficient and transparent regulatory pathway to market for new sunscreens and advocating against proposals that limit access to FDA-approved sunscreens.
A Certified Organic Sunscreen, also known as Petrochemical-Free Sunscreen, is a third party certified sunscreen product consisting of certified and approved organic ingredients, with typically zinc oxide acting as the photo-protector. An organic sunscreen is verified and approved by a certifier to international or national organic standards, such as NSF/ANSI 305 and USDA organic, which define production and labelling requirements for personal care products containing organic ingredients. These standards are complemented by existing sunscreen regulatory bodies such as the FDA that regulate the efficacy of the sunscreen, safety and permitted ingredients. Generally speaking, sunscreen has photo-protective properties that reduce the risk of skin cancer and ageing with relation to the SPF value and proper application.