Avobenzone (trade names Parsol® 1789, Eusolex® 9020, Escalol® 517 and others, INCI Butyl Methoxydibenzoylmethane) is an oil soluble ingredient used in sunscreen products to absorb the full spectrum of UVA rays. It is a dibenzoylmethane derivative. Its ability to absorb ultraviolet light over a wider range of wavelengths than many organic sunscreen agents has led to its use in many commercial preparations marketed as "broad spectrum" sunscreens.
Avobenzone was patented in 1973 and was approved in the EU in 1978. It was approved by the FDA in 1988. Its use is approved world wide.
Avobenzone has been shown to degrade significantly in light, resulting in less protection over time. The UV-A light in a day of sunlight in a temperate climate is sufficient to break down most of the compound. This degradation can be reduced by using a photostabilizer, like octocrylene. Other photostabilizers include:
- 4-Methylbenzylidene camphor (USAN Enzacamene)
- Tinosorb® S (USAN Bemotrizinol, INCI Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine)
- Tinosorb® M (USAN Bisoctrizole, INCI Methylene Bis-Benzotriazolyl Tetramethylbutylphenol)
- Butyloctyl Salicylate
- Hexadecyl Benzoate
- Butyloctyl Benzoate
- Mexoryl® SX (USAN Ecamsule, INCI Terephthalylidene Dicamphor Sulfonic Acid)
- Corapan® TQ (INCI Diethylhexyl 2,6-Naphthalate)
- Parsol® SLX (INCI Polysilicone-15)
- Oxynex® ST (INCI Diethylhexyl Syringylidene Malonate)
Complexing avobenzone with cyclodextrins may also increase its photostability.
According to some studies, "the most effective sunscreens contain avobenzone and titanium dioxide."  The combination with TiO2 is approved for use in the EU, but in the US the FDA has yet to approve this, stating (in 1997) that "until complete and adequate data have been submitted, the agency has no basis to allow other avobenzone combinations" (containing titanium dioxide).(this is wrong) Avobenzone can degrade faster in light in combination with mineral UV absorbers like zinc oxide and titanium dioxide, though with the right coating of the mineral particles this reaction can be reduced. A manganese doped titanium dioxide may be better than undoped titanium dioxide to improve avobenzone's stability.
Avobenzone reacts with minerals to form colored complexes. Manufacturers of avobenzone, like DSM recommend to include a chelator to prevent this from happening. They also recommend to avoid the inclusion of iron and ferric salts, heavy metals, formaldehyde donors and PABA and PABA esters.
The makers of Coppertone advise that avobenzone binds iron and can cause staining of clothes washed in iron-rich water.
- ↑ Chatelain E, Gabard B. (2001). "Photostabilization of Butyl methoxydibenzoylmethane (Avobenzone) and Ethylhexyl methoxycinnamate by Bis-ethylhexyloxyphenol methoxyphenyl triazine (Tinosorb S), a new UV broadband filter". Photochem Photobiol. 74(3): 401–6. PMID 11594052. Unknown parameter
- ↑ Tarras-Wahlberg N, Stenhagen G, Larko O, Rosen A, Wennberg AM, Wennerstrom O (1999). "Changes in ultraviolet absorption of sunscreens after ultraviolet irradiation". J Invest Dermatol. 113(4): 547–53. PMID 10504439. Unknown parameter
- ↑ Wetz F, Routaboul C, Denis A, Rico-Lattes I (2005). "A new long-chain UV absorber derived from 4-tert-butyl-4'-methoxydibenzoylmethane: absorbance stability under solar irradiation". J Cosmet Sci. 56(2): 135–48. PMID 15870853. Unknown parameter
- ↑ Bonda C., Steinberg D. C. (2000). "A new photostabilizer for full spectrum sunscreens". Cosmet. Toiletries. 115(6): 37–45.
- ↑ Chaudhuri RK, Lascu Z, Puccetti G, Deshpande AA, Paknikar SK (2006). "Design of a photostabilizer having built-in antioxidant functionality and its utility in obtaining broad-spectrum sunscreen formulations". Photochem Photobiol. 82(3): 823–8. PMID 16492073. Unknown parameter
- ↑ Scalia S, Simeoni S, Barbieri A, Sostero S (2002). "Influence of hydroxypropyl-beta-cyclodextrin on photo-induced free radical production by the sunscreen agent, butyl-methoxydibenzoylmethane". J Pharm Pharmacol. 54(11): 1553–8. PMID 12495559. Unknown parameter
- ↑ Warwick L. Morison, M.D. (Mar 11, 2004.). "Photosensitivity". The New England Journal of Medicine. 350: 1111–1117. Check date values in:
- ↑ NEW-WAVE SUNSCREENS: Active ingredient makers are frustrated by the long list of sunscreens and UV-A testing protocols that are still awaiting FDA decisions, Chemical & Engineering News, April 11, 2005, Volume 83, Number 15, pp. 18-22. Online version
- ↑ "Sunscreen Drug Products for Over-the-Counter use; Marketing Status of Products Containing Avobenzone; Enforcement Policy" (PDF). US Food and Drug Administration. April 30, 1997. p. 23354. Retrieved Jun 3, 2007.
- ↑ Stability Study of Avobenzone with Inorganic Sunscreens, Kobo Products Poster, 2001, Online version
- ↑ Wakefield G, Lipscomb S, Holland E, Knowland J (2004). "The effects of manganese doping on UVA absorption and free radical generation of micronised titanium dioxide and its consequences for the photostability of UVA absorbing organic sunscreen components". Photochem Photobiol Sci. 3(7): 648–52. PMID 15238999. Unknown parameter