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RP irradiated by UVC light produced AR, palmitic acid, and 2-butenyl palmitate . AR was also formed from photoirradiation of RP in ethanol under UVA light .
Many cosmetics contain retinoid-based compounds, such as for example retinyl palmitate , either to protect the skin or to stimulate skin responses which will correct skin damaged by sunlight. However, little is well known concerning the photodecomposition of some retinoids and the toxicity of the retinoids and their sunlight-induced photodecomposition products on skin.

• The solvent make a difference both extent of isomerization of the trans-retinoids and the relative amounts of the various cis-isomers formed .

However, retinyl acetate was reported as a co-carcinogen in carcinogenesis studies with butylated hydroxyanisole using male F344 rats . The consequences of topically applied RA on photocarcinogenicity in mice have been investigated by several research groups (42–47). The results are very varied, with retinoid application increasing, decreasing, or having no influence on photocarcinogenesis. The drastically different effects on tumor incidence often will be ascribed to differences in study design, specially the usage of different light sources and doses of light radiation. However, the current understanding of the effects of RA on photocarcinogenesis does not allow a mechanistic explanation for the various outcomes. During photoirradiation, the principal retinoid photodecomposition products

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can also isomerize to secondary products. For instance, as shown in Figure 4, anhydroretinol formed from photoirradiation of RP is initially in a trans-form. But during photoirradiation, it isomerizes right into a combination of all-trans-AR and three cis-ARs . Reddy and Rao studied the photoirradiation of retinyl acetate, and showed that isomerization of retinyl acetate and its photodecomposition product proceeded via an ionic photodissociation mechanism .
Individuals who are photosensitive may develop skin rashes or burns, even after only limited contact with the sun. Yan J., Cherng S.-H., Xia Q., Wamer W. G., Bucher J. R., Howard P. C., Yu H., Fu P. P. Photoclastogenicity of retinyl palmitate and its photodecomposition products. The best way to prevent symptoms of photosensitivity would be to limit the quantity of time you spend in the sun. Individuals who are photosensitive should always use sunscreen when outside. Your doctor will require a complete overview of your medical history and the medications you’re currently taking to produce a proper diagnosis.

• Fu P. P., Cherng S.-H., Coop L., Xia Q., Culp S. J., Tolleson W. H., Wamer W. G., Howard P. C. Photoreaction, phototoxicity, and photocarcinogenicity of retinoids.
• Photochemical reactions of retinoids undergo a number of different routes, including photoisomerization, photopolymerization, photooxidation, and photodegradation (11–13).
• that cellular retinol binding protein protects retinol from photodegradation .

Phototoxic reactions are caused when a new chemical within your body interacts with UV rays from the sun. Medications like doxycycline and tetracycline, for example, are the most typical cause of this sort of reaction. Abe T., Oue N., Yasui W., Ryoji M. Rapid and preferential induction of ATF3 transcription in response to low doses of UVA light. Ferguson J., Johnson B. E. Retinoid assoicated phototoxicity and photosensitivity.

Photoallergic

[newline]Sliney D. H. Photoprotection of the attention – UV radiation and sunglasses.

They will focus on the development and patterns of rashes with regards to your sun exposure. People with this condition can develop an itchy rash if they are exposed to sunlight. As sun exposure continues and UV tolerance increases, symptoms generally appear less often.

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These and other factors result in the generation of action spectra for photoinjuries to skin and eye components. The TLV were established in 1996 by the American Conference of Governmental Industrial Hygenists . Upon photoirradiation, retinoids including ROH, RA, RP, and retinyl acetate isomerize right into a mixture of trans- and cis-isomers . The solvent make a difference both extent of isomerization of the trans-retinoids and the relative levels of the different cis-isomers formed . All-trans-RA and 13-cis-RA are recognized to undergo Z-E isomerization and oxidation when subjected to light and air .