Ecamsule
Ecamsule
Chemical compound
Ecamsule (USAN, trade name Mexoryl SX, INCI terephthalylidene dicamphor sulfonic acid) 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.[2]
Names | |
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IUPAC name
[(3Z)-3-[[4-[(Z)-[7,7-Dimethyl-2-oxo-1-(sulfomethyl)-3-bicyclo[2.2.1]heptanylidene]methyl]phenyl]methylidene]-7,7-dimethyl-2-oxo-1-bicyclo[2.2.1]heptanyl]methanesulfonic acid | |
Other names
Mexoryl SX; Terephthalylidene dicamphor sulfonic acid | |
Identifiers | |
3D model (JSmol) |
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ChEMBL | |
ChemSpider |
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ECHA InfoCard | 100.101.049 |
PubChem CID |
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UNII | |
CompTox Dashboard (EPA) |
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Properties | |
C28H34O8S2 | |
Molar mass | 562.69 g·mol−1 |
Melting point | 255 °C (491 °F; 528 K) (dec) [1] |
log P | 1.35 [1] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Although there are a few different UV absorbers with the trade name Mexoryl, only two of them are widely used where approved. Mexoryl SX (water-soluble) and Mexoryl XL (INCI Drometrizole trisiloxane, oil-soluble). Together they show a synergistic effect in protection.[3] The patents are held by L'Oréal. Sunscreens containing ecamsule are exclusive to L'Oréal and its brands.
Exposed to UV, ecamsule undergoes reversible photoisomerization, followed by photoexcitation. The absorbed UV is then released as thermal energy, without penetrating the skin.
UVB rays cause short-term sunburn and skin cancer; UVA rays cause wrinkling and may have some role in development of skin cancer. There is no official rating for UVA protection in the US. In Europe, there are several different rating systems that are used to measure effectiveness in blocking UVA rays, including the IPD (immediate pigment darkening assay) and the PPD (persistent pigment darkening assay). The UVB range is 280 to 320 nanometers, and the UVA range is 320 to 400. Ecamsule protects against UV wavelengths in the 290–400 nanometer range, with peak protection at 345 nm.[4][5] Because ecamsule does not cover the entire UV spectrum, it should be combined with other active sunscreen agents to ensure broad-spectrum UV protection. Ecamsule is a photostable organic UVA absorber, meaning it doesn't degrade significantly when exposed to light. This is in contrast to the widely used UVA absorber avobenzone that is not intrinsically photostable and requires photostabilizers to prevent significant degradation in light.[6][7][8]
A 5% ecamsule containing sunscreen can prevent early changes leading to photoaging in humans. A broad spectrum sunscreen with ecamsule, avobenzone and octocrylene significantly reduces the skin damage associated with UV exposure in human subjects.[9]
In studies done in mice it reduces the formation of UV induced pyrimidine dimers and delays the onset of skin cancer. In vitro ecamsule effectively protects against the harmful effects of UV.[10]
Ecamsule has little percutaneous absorption and little systemic effects, therefore it is considered relatively safe.[11] A mouse study shows that it does not increase the probability of promoting skin cancer.[12] Studies done in vitro show that it is not photomutagenic.[13]
Because ecamsule is an acid it needs to be neutralized in order to be used without offsetting the final pH of the sunscreen too much. Usually this is done with triethanolamine.
L'Oréal patented ecamsule first in 1982. It was approved in the EU in 1991. Sunscreens based on ecamsule have been available in Europe, Canada and other parts of the world since 1993. Ecamsule was given approval by the FDA in 2006 to be used in the U.S.[14] However this approval only extends to ecamsule-containing sunscreens registered under a New Drug Application, not ecamsule itself.[15][16]
- "ecamsule". www.chemsrc.com.
- Fourtanier A, Labat-Robert J, Kern P, Berrebi C, Gracia AM, Boyer B (April 1992). "In vivo evaluation of photoprotection against chronic ultraviolet-A irradiation by a new sunscreen Mexoryl SX". Photochem Photobiol. 55 (4): 549–60. doi:10.1111/j.1751-1097.1992.tb04277.x. PMID 1320278. S2CID 24857771.
- Seite S, Moyal D, Richard S, de Rigal J, Leveque JL, Hourseau C, Fourtanier A (June 1998). "Mexoryl SX: a broad absorption UVA filter protects human skin from the effects of repeated suberythemal doses of UVA". J Photochem Photobiol B. 44 (1): 69–76. doi:10.1016/S1011-1344(98)00122-5. PMID 9745729.
- Chatelain E, Gabard B (September 2001). "Photostabilization of Butyl methoxydibenzoylmethane (Avobenzone) and Ethylhexyl methoxycinnamate by Bis-ethylhexyloxyphenol methoxyphenyl triazine (Tinosorb S), a new UV broadband filter". Photochemistry and Photobiology. 74 (3): 401–6. doi:10.1562/0031-8655(2001)074<0401:POBMAA>2.0.CO;2. ISSN 0031-8655. PMID 11594052.
- Tarras-Wahlberg N, Stenhagen G, Larko O, Rosen A, Wennberg AM, Wennerstrom O (October 1999). "Changes in ultraviolet absorption of sunscreens after ultraviolet irradiation". J Invest Dermatol. 113 (4): 547–53. doi:10.1046/j.1523-1747.1999.00721.x. PMID 10504439.
- Wetz F, Routaboul C, Denis A, Rico-Lattes I (Mar–Apr 2005). "A new long-chain UV absorber derived from 4-tert-butyl-4'-methoxydibenzoylmethane: absorbance stability under solar irradiation". Journal of Cosmetic Science. 56 (2): 135–48. doi:10.1562/2004-03-09-ra-106. PMID 15870853.
- Seité S, Colige A, Piquemal-Vivenot P, Montastier C, Fourtanier A, Lapière C, Nusgens B (August 2000). "A full-UV spectrum absorbing daily use cream protects human skin against biological changes occurring in photoaging". Photodermatol Photoimmunol Photomed. 16 (4): 147–55. doi:10.1034/j.1600-0781.2000.160401.x. PMID 11019938. S2CID 23813660.
- Dean SW, Dunmore RH, Ruddock SP, Dean JC, Martin CN, Kirkland DJ (May 1992). "Development of assays for the detection of photomutagenicity of chemicals during exposure to UV light. II. Results of testing three sunscreen ingredients". Mutagenesis. 7 (3): 179–82. doi:10.1093/mutage/7.3.179. PMID 1602971.
- "FDA approves Mexoryl in L'Oreal sunscreen". cosmeticsdesign.com.
- "redirecting". www.cosmeticsandtoiletries.com.
- Why Is the Best Sunscreen Blocked by FDA?, John Stossel, 20/20 abcnews.com, June 17, 2005