Retinyl palmitate, or vitamin A palmitate, is the ester of retinol (vitamin A) and palmitic acid, with formula C36H60O2. It is the most abundant form of vitamin A storage in animals.[2]
Animals use long-chain esters of vitamin A, most abundantly the palmitate form, as a form of vitamin A storage. The storage reaction is catalyzed by LRAT, and the inverse is catalyzed by REH.[2] The esters are also intermediates in the visual cycle: RPE65 isomerizes the retinyl part to 11-cis-retinal.[2]
Usesedit
Vitamin A palmitate 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).[5]
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), though neither its skin absorption[6] nor its conversion[7] is very effective.
Carcinogenicity controversyedit
New York Senator Chuck Schumer has called attention to the fact that high doses of topical retinyl palmitate were shown to accelerate cancer in lab animals,[8] fueling the sunscreen controversy in the popular press.[9] One toxicological analysis determined that "there is no convincing evidence to support the notion that [retinyl palmitate] in sunscreens is carcinogenic."[9] 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.[10]
Teratogenicityedit
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."[11] Preformed Vitamin A refers to retinyl palmitate and retinyl acetate.
^E. A. Duell, S. Kang & J. J. Voorhees (1997). "Unoccluded retinol penetrates human skin in vivo more effectively than unoccluded retinyl palmitate or retinoic acid". The Journal of Investigative Dermatology. 109 (3): 301–305. doi:10.1111/1523-1747.ep12335788. PMID 9284094.
^Boehnlein, James; Sakr, Adel; Lichtin, J. Leon; Bronaugh, Robert L. (1994). "Characterization of Esterase and Alcohol Dehydrogenase Activity in Skin. Metabolism of Retinyl Palmitate to Retinol (Vitamin A) During Percutaneous Absorption". Pharmaceutical Research. 11 (8): 1155–1159. doi:10.1023/A:1018941016563. ISSN 0724-8741. PMID 7971717. S2CID 25458156.
^"Possible link between ingredient in sunscreen and skin cancer: Schumer". New York Daily News. June 14, 2010.
^ abWang, 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.
^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.
retinyl, palmitate, vitamin, palmitate, ester, retinol, vitamin, palmitic, acid, with, formula, c36h60o2, most, abundant, form, vitamin, storage, animals, namesiupac, name, retinyl, hexadecanoatesystematic, iupac, name, dimethyl, trimethylcyclohex, nona, tetra. Retinyl palmitate or vitamin A palmitate is the ester of retinol vitamin A and palmitic acid with formula C36H60O2 It is the most abundant form of vitamin A storage in animals 2 Retinyl palmitate NamesIUPAC name Retinyl hexadecanoateSystematic IUPAC name 2E 4E 6E 8E 3 7 Dimethyl 9 2 6 6 trimethylcyclohex 1 en 1 yl nona 2 4 6 8 tetraen 1 yl hexadecanoateOther names Retinol palmitateIdentifiersCAS Number 79 81 2 Y3D model JSmol Interactive imageChEBI CHEBI 17616ChEMBL ChEMBL1675 NChemSpider 10618934 YECHA InfoCard 100 001 117KEGG D00164PubChem CID 5280531UNII 1D1K0N0VVC YCompTox Dashboard EPA DTXSID1021241InChI InChI 1S C36H58O3 c1 7 8 9 10 11 12 13 14 15 16 17 18 19 25 34 37 39 35 38 29 31 3 23 20 22 30 2 26 27 33 32 4 24 21 28 36 33 5 6 h20 22 23 26 27 29H 7 19 21 24 25 28H2 1 6H3 b23 20 27 26 30 22 31 29 YKey SLCSFDSJAUMVCI UQEJEMEYSA N YInChI 1 C36H58O3 c1 7 8 9 10 11 12 13 14 15 16 17 18 19 25 34 37 39 35 38 29 31 3 23 20 22 30 2 26 27 33 32 4 24 21 28 36 33 5 6 h20 22 23 26 27 29H 7 19 21 24 25 28H2 1 6H3 b23 20 27 26 30 22 31 29 Key SLCSFDSJAUMVCI UQEJEMEYBQSMILES CC1 C CCCC C C1 C C C C C C C C C C C O OC O CCCCCCCCCCCCCCCPropertiesChemical formula C36H60O2Molar mass 524 86 g molSolubility in water In water ethanol and ethers 1 HazardsNFPA 704 fire diamond 010Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa N verify what is Y N Infobox references An alternate spelling retinol palmitate which violates the yl organic chemical naming convention for esters is also frequently seen In 2021 vitamin A was the 298th most commonly prescribed medication in the United States with more than 500 000 prescriptions 3 4 Contents 1 Biology 2 Uses 3 Carcinogenicity controversy 4 Teratogenicity 5 See also 6 ReferencesBiology editAnimals use long chain esters of vitamin A most abundantly the palmitate form as a form of vitamin A storage The storage reaction is catalyzed by LRAT and the inverse is catalyzed by REH 2 The esters are also intermediates in the visual cycle RPE65 isomerizes the retinyl part to 11 cis retinal 2 Uses editVitamin A palmitate 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 mg 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 5 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 though neither its skin absorption 6 nor its conversion 7 is very effective Carcinogenicity controversy editNew York Senator Chuck Schumer has called attention to the fact that high doses of topical retinyl palmitate were shown to accelerate cancer in lab animals 8 fueling the sunscreen controversy in the popular press 9 One toxicological analysis determined that there is no convincing evidence to support the notion that retinyl palmitate in sunscreens is carcinogenic 9 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 10 Teratogenicity editWorld 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 mg RE at any time during pregnancy 11 Preformed Vitamin A refers to retinyl palmitate and retinyl acetate See also editVitamin A Retinyl acetate Vitamin supplementReferences edit William M Haynes 2014 2015 CRC Handbook of Chemistry and Physics 95th ed CRC Press p 622 ISBN 978 1 4822 08672 a b c O Byrne SM Blaner WS July 2013 Retinol and retinyl esters biochemistry and physiology Journal of Lipid Research 54 7 1731 43 doi 10 1194 jlr R037648 PMC 3679378 PMID 23625372 The Top 300 of 2021 ClinCalc Archived from the original on 15 January 2024 Retrieved 14 January 2024 Vitamin A Drug Usage Statistics ClinCalc Retrieved 14 January 2024 Vitamin A Linus Pauling Institute E A Duell S Kang amp J J Voorhees 1997 Unoccluded retinol penetrates human skin in vivo more effectively than unoccluded retinyl palmitate or retinoic acid The Journal of Investigative Dermatology 109 3 301 305 doi 10 1111 1523 1747 ep12335788 PMID 9284094 Boehnlein James Sakr Adel Lichtin J Leon Bronaugh Robert L 1994 Characterization of Esterase and Alcohol Dehydrogenase Activity in Skin Metabolism of Retinyl Palmitate to Retinol Vitamin A During Percutaneous Absorption Pharmaceutical Research 11 8 1155 1159 doi 10 1023 A 1018941016563 ISSN 0724 8741 PMID 7971717 S2CID 25458156 Possible link between ingredient in sunscreen and skin cancer Schumer New York Daily News June 14 2010 a b 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 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 Safe vitamin A dosage during pregnancy and lactation PDF World Health Organization WHO 1998 Retrieved from https en wikipedia org w index php title Retinyl palmitate amp oldid 1196723908, wikipedia, wiki, book, books, library,
