Benzophenone sunscreens

Chlorpromazine most often causes photosensitivity reactions (incidence around 3%), which may result from formation of a cytotoxic by-product after exposure to ultraviolet light. Patients should be advised to avoid prolonged exposure to strong indoor light, to wear protective clothing, and to use a combined para-aminobenzoic acid plus benzophenone sunscreen when exposure to strong sunlight is unavoidable. 

Anti UVA. [Aceto] 2-Hydroxy-4-methoxy benzophenone sunscreen agent... 

Seven benzophenone sunscreen agents (benzophenones 1, 2, 3, 4, 5, 8, 10 often hydroxylated and/or methoxylated benzophenones) were extracted from suncreams, lipsticks, and other personal care products and separated on a C g column (A = 286nm). A 30/30/40 methanol/acetonitrile/water mobile phase generated good peak shapes and resolution in 40 min [255]. All detection limits were similar and were reported as about 1 mg/L. 

Benzophenone sunscreen agents, 119 Benzo[a]pyrene, 97, 99 Benzo[a]pyrene triols, 99, 231 Benzo[/)]quinoline, 347 Benzothiazole, 340 Benzosuberone-4-sulfonic acid, 270 2-Benzothiazole-2,2 -disulfide, 124 5-Benzoyl-2-acctylthiophene, 255 Benzpylecgonine, 312i, 492 5-Benzoyl-2-ethylthiophene, 255 Benzoylmercury, 93 Benzoylnorecgonine, 312... 

These sunscreen ingredients include octyl-dimethyl-PABA (UVB), 2-ethylhexyl-p-meth-oxycinnamate (UVB),octocrylene (UVA/UVB), octyl salicylate (UVB), benzophenones (UVB/ UVA), and methyl anthranilate (UVA). Avoben-zone or Parsol 1789 and mexoryl, a benzylidene camphor, block UVA. Mexoryl is the most efficient of the UVA organic sunscreens [10]. Many sunscreen formulations combine ingredients to maximize photoprotection. 

Sun worshipers and those who work outside can protect themselves from ultraviolet exposure with skin creams that contain UV-absorbing molecules. The UV-absorbing molecule in the first sunscreens was PABA, para-aminobenzoic acid. However, this compound may have toxic effects of its own. The UV-absorbing components of current sunscreens are derivatives of cinnamic acid and benzophenone. 

After developing a method to quantitate the generation of ROS in skin, we could begin to study how the number of ROS can be reduced by the application of FDA-approved UV filters used in sunscreens (Hanson et al. 2006). Our measurements showed that octocrylene (OC), octylmethoxycinnamate (OMC), and benzophenone-3... 

FIG U RE 2.7 Three FDA-approved U V filters commonly used in over-the-counter sunscreens (a) benzophenone-3 (B3), (b) octocrylene (OC), and (c) octylmethoxycinnamate (OMC). 

Topical medications useful in protecting against sunlight contain either chemical compounds that absorb ultraviolet light, called sunscreens, or opaque materials such as titanium dioxide that reflect light, called sunshades. The three classes of chemical compounds most commonly used in sunscreens are p-aminobenzoic acid (PABA) and its esters, the benzophenones, and the dibenzoylmethanes. 

Another very common use of phenolic compounds is in sunscreens. The presence of the aromatic ring results in the effective absorbance of the UV-B radiation (between 280 and 315 nm) from the sun and thus prevents sunburns. The most common active ingredient in many sunscreens is p-aminobenzoic acid (PABA 7.1), which is actually not a phenolic compound. This compound has been widely used since the 1970 s but is less popular nowadays due to the formation of skin rashes and acne. As a result many sunscreens are now PABA-free. Alternative active ingredients include salicylates such as octylsalicylate (7.2), cinnamates such as octyl methylcinnamate (7.3), benzophenone (7.4) and the related compound oxybenzone (7.5), and anthranilates, such as menthylanthranilate (7.6). Octyl methylcinnamate (7.3) is insoluble in water and is therefore commonly... 

Cosmetic products that are photoallergenic include fragrances, such as musk ambrette and 6-methylcoumarin, and sunscreens (e.g., para-aminobenzoic acid and its derivatives, benzophenones, dibenzoylmethanes).17 Oil of bergamot, previously a popular ingredient in fragrances, has now been eliminated from most perfumes due to its phototoxic properties.24... 

Jiang R, Benson HAE, Cross SE, and Roberts MS. In vitro human epidermal and polyethylene membrane penetration and retention of the sunscreen benzophenone-3 from a range of solvents. Pharm. Res. 1998 15(12) 1863-1868. 

Benzophenone 3 Sunscreens Benzophenone 3 -i- (concentration not stated) Not done (17)... 

Patients own products, diluted as appropriate, should be tested as well (5). Currently, UV filters (and to a lesser extent fragrances) are the main photosensitizers, notably benzophenone-3. Sunscreen photosensitization occurs especially in patients with photodermatoses and photo-aggravated dermatoses (3). The UV filter isopropyl dibenzoyhnethane caused so many cases of photosensitization that it was withdrawn. 

In 19 patients with positive photopatch tests to sunscreens among all the patients that were photopatch-tested between 1992 and 1999 (total not stated) there were 21 positive photopatch tests to sunscreen agents (3). Nine patients reacted to oxybenzone, eight to butylmethoxydibenzoylmethane, three to methoxycinnamate, and one to benzophenone. There were no reactions to para-aminobenzoic acid (PABA), reflecting the increased use of PABA-free sunscreens. Six patients also had positive patch tests to components of the... 

Oxybenzone is the most frequently used benzophenone in sunscreens, estimated to be present in 20-30% of commercial products. Phototoxicity and allergic contact dermatitis have been described, but reports of immediate-type hypersensitivity are scarce. 

Octyl triazone is a UVB absorber structurally unrelated to the benzophenones. Photocontact allergy to this agent in a sunscreen has been described (7). 

Photoallergic responses to sunscreen products represent an area where chemical components not known to produce dermal allergic responses are activated by solar radiation to produce ACD. I45 46 It is hypothesized here that in these instances, electromagnetic radiation may activate the skin to adsorb and/or absorb species that do not so react without the incident radiation. Alternatively, the molecular species themselves are excited by the radiation to molecular states that make them more reactive to skin. Chemicals exhibiting photoallergic contact dermatitis include oxybenzone, butyl methoxy dibenzoylmethane, methoxycinnamate, and benzophenone—all molecules that are readily photoexcitedJ45 ... 

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