Retinyl palmitate

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Retinyl palmitate
Retinyl palmitate.png
Retinyl palmitate spacefill.png Retinyl palmitate2.png
Identifiers
CAS number 79-81-2 YesY
PubChem 5280531
ChemSpider 10618934 YesY
UNII 1D1K0N0VVC YesY
Jmol-3D images Image 1
Properties
Molecular formula C36H60O2
Molar mass 524.86 g/mol
Hazards
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g., sodium chloride Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

Retinyl palmitate, or vitamin A palmitate, is the ester of retinol (vitamin A) and palmitic acid, with formula C36H60O2.

An alternate spelling, retinol palmitate, which violates the -yl organic chemical naming convention for esters, is also frequently seen.

Uses[edit]

Retinyl palmitate is a synthetic alternate for retinyl acetate in vitamin A supplements, and is available in oily or dry forms. It is a common vitamin supplement, available in both oral and injectable forms for treatment of vitamin A deficiency, under the brand names Aquasol A, Palmitate A and many others. It is a constituent of intra ocular treatment for dry eyes at a concentration of 138 µg/g (VitA-Pos) by Ursapharm. It is a pre-formed version of vitamin A; therefore, the intake should not exceed the Recommended Dietary Allowance (RDA). Overdosing preformed Vitamin A forms such as retinyl palmitate leads to adverse physiological reactions (hypervitaminosis A).[1]

Retinyl palmitate is used as an antioxidant and a source of vitamin A added to low fat milk and other dairy products to replace the vitamin content lost through the removal of milk fat. Palmitate is attached to the alcohol form of vitamin A, retinol, in order to make vitamin A stable in milk.[citation needed]

Retinyl palmitate is also a constituent of some topically applied skin care products. After its absorption into the skin, retinyl palmitate is converted to retinol, and ultimately to retinoic acid (the active form of vitamin A present in Retin-A).

Carcinogenicity controversy[edit]

The Environmental Working Group (EWG) and New York Senator Chuck Schumer have called attention to the fact that high doses of topical retinyl palmitate were shown to accelerate cancer in lab animals,[2] fueling the sunscreen controversy in the popular press.[3] Although concerns about other sunscreen ingredients remain undisputed,[citation needed] one toxicological analysis determined that "there is no convincing evidence to support the notion that [retinyl palmitate] in sunscreens is carcinogenic."[4] The EWG has since refuted this analysis directly.[5] A technical report issued thereafter by the National Toxicology Program concluded that diisopropyl adipate increased incidence of skin tumors in mice, and the addition of either retinoic acid or retinyl palmitate both exacerbated the rate and frequency of tumors.[6]

Teratogenicity[edit]

World Health Organization recommendation on Maternal Supplementation During Pregnancy states that "health benefits are expected for the mother and her developing fetus with little risk of detriment to either, from a daily supplement not exceeding 10,000 IU [preformed] vitamin A (3000 µg RE) at any time during pregnancy."[7] Preformed Vitamin A refers to retinyl palmitate and retinyl acetate.

See also[edit]

References[edit]

  1. ^ Vitamin A, Linus Pauling Institute
  2. ^ "Possible link between ingredient in sunscreen and skin cancer: Schumer". New York Daily News. June 14, 2010. 
  3. ^ Wang, SQ; Dusza, SW; Lim, HW (2010). "Safety of retinyl palmitate in sunscreens: a critical analysis.". Journal of the American Academy of Dermatology 63 (5): 903–6. doi:10.1016/j.jaad.2010.07.015. PMID 20692724. 
  4. ^ Wang, SQ; Dusza, SW; Lim, HW (2010). "Safety of retinyl palmitate in sunscreens: a critical analysis.". Journal of the American Academy of Dermatology 63 (5): 903–6. doi:10.1016/j.jaad.2010.07.015. PMID 20692724. 
  5. ^ Lunder, S. (2011). What scientists say about Vitamin A in sunscreen. Available at http://www.ewg.org/research/what-scientists-say-about-vitamin-sunscreen. Accessed September 19, 2013.
  6. ^ National Toxicology Program. (2012). NTP technical report on the photocarcinogenesis study of retinoic acid and retinyl palmitate [CAS Nos. 302-79-4 (All-trans-retinoic acid) and 79-81-2 (All-trans-retinyl palmitate)] in SKH-1 mice (Simulated solar light and topical application study). Available at http://ntp.niehs.nih.gov/ntp/htdocs/LT_rpts/TR568_508.pdf. Accessed September 19, 2013.
  7. ^ Safe vitamin A dosage during pregnancy and lactation, WHO, 1998