Retinyl palmitate

Structural formula
General
Surname	[(2 E , 4 E , 6 E , 8 E ) -3,7-dimethyl-9- (2,6,6-trimethylcyclohex-1-en-1-yl) nona-2,4,6,8- tetraenyl] hexadecanoate
other names	Vitamin A palmitate Retinol palmitate
Molecular formula	C 36 H 60 O 2
Brief description	Viscose, partly yellowish crystalline, mild odor
External identifiers / databases
CAS number 79-81-2 EC number 201-228-5 ECHA InfoCard 100.009.691 PubChem 5280531 ChemSpider 10618934 Wikidata Q7316807
properties
Molar mass	524.86 g · mol -1
Physical state	liquid or solid
density	0.921 g cm −3
Melting point	26 ° C
boiling point	approx. 100 ° C
solubility	0.001 g · l -1 (water)
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 360D-413 P: 201-308 + 313
Toxicological data	7,910 mg kg −1 ( LD 50 ,  rat , oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Retinyl palmitate also called vitamin A palmitate or retinol palmitate is the carboxylic acid ester that results from the esterification reaction of retinol (vitamin A) with palmitic acid .

use

Retinyl palmitate is often replaced by its synthetic alternative, retinyl acetate, in vitamin A supplements and is available in oily or dry form. It's a common vitamin supplement that is available in both oral and injectable forms to treat vitamin A deficiency. It is offered under the following product names:

• Aquasol A
• Palmitate A

It is also part of the intraocular treatment of dry eyes in a concentration of approx. 138 μg / g (e.g. VitA-Pos) by Ursapharm . It's a preformed version of vitamin A; therefore intake should not exceed the Recommended Daily Allowance (RDA). An overdose of preformed vitamin A forms such as retinyl palmitate leads to disadvantageous physiological reactions ( hypervitaminosis A).

Retinyl palmitate is also used as an antioxidant and vitamin A source in low-fat milk and other dairy products to replace the vitamins lost through the removal of milk fat .

Retinyl palmitate is also found in some typical skin care products. Once absorbed into the skin, retinyl palmitate is converted to retinol and then to retinoic acid (the active form of vitamin A found in Retin-A), although neither its skin absorption nor conversion is very effective.

pregnancy

The World Health Organization (WHO) recommendation for preformed vitamin A supplements (retinyl palmitate or retinyl acetate) by mothers during pregnancy states that "there are health benefits for the mother and her developing fetus with a low risk of impairment as long as a daily supplement is taken is ingested no more than 10,000 IU of preformed vitamin A (3,000 μg retinol ) . "

Carcinogenicity Controversy

New York Senator Chuck Schumer has pointed out that high doses of retinyl palmitate have been shown to cause cancer in animal experiments. This fueled the controversy surrounding sunscreens containing retinyl palmitate. A toxicological analysis found that "there is no convincing evidence to support the belief that [retinyl palmitate] in sunscreens is carcinogenic". A technical report later published by the National Toxicology Program concluded that diisopropyl adipate increased the incidence of skin tumors in mice, and the addition of either retinoic acid or retinyl palmitate worsened both the rate and incidence of tumors.

Occurrence in nature

The retinyl palmitate is mainly found in fatty marine fish z. B. in cod and halibut , in mammalian liver, in milk , butter and egg yolk , in the body fat of many animals and in the form of provitamins ( carotenoids ) in plants .

See also

• Vitamin A
• Retinoic acids
• Retinol

Individual evidence

1. ↑ ^{a b c d e f g h} Entry for CAS no. 79-81-2 in the GESTIS substance database of the IFA , accessed on April 14, 2020(JavaScript required) .
2. ↑ Safety data sheet Retinyl Palmitate. Sigma-Aldrich , accessed April 1, 2020 . 
3. ^ Vitamin A , Linus Pauling Institute.
4. ^ Peter Nuhn: Naturstoffchemie , S. Hirzel Wissenschaftliche Verlagsgesellschaft, Stuttgart, 2nd edition, 1990, ISBN 3-7776-0473-9 , pp. 339–341.
5. ^ EA Duell, S. Kang & JJ Voorhees: Unoccluded retinol penetrates human skin in vivo more effectively than unoccluded retinyl palmitate or retinoic acid . In: Journal of Investigative Dermatology . tape 109 , no. 3 , 1997, p. 301-305 , doi : 10.1111 / 1523-1747.ep12335788 , PMID 9284094 .
6. ↑ J. Boehnlein, A. Sakr, JL Lichtin, RL Bronaugh: Characterization of Esterase and Alcohol Dehydrogenase Activity in Skin. Metabolism of Retinyl Palmitate to Retinol (Vitamin A) During Percutaneous Absorption . tape 11 , no. 8 . Pharmaceutical Research, 1994, ISSN  0724-8741 , pp. 1155-1159 , doi : 10.1023 / A: 1018941016563 .
7. ↑ Safe vitamin A dosage during pregnancy and lactation. WHO , accessed April 1, 2020 . 
8. ↑ Possible link between ingredients in sunscreen and skin cancer: Schumer . In: New York Daily News , June 14, 2010. 
9. ↑ ^{a b} SQ. Wang, SW. Dusza, HW. Lim: Safety of retinyl palmitate in sunscreens: a critical analysis. In: Journal of the American Academy of Dermatology . tape 63 , no. 5 , 2010, p. 903-6 , doi : 10.1016 / j.jaad.2010.07.015 , PMID 20692724 .
10. ↑ 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). National Toxicology Program , accessed April 1, 2020 .  
11. ↑ G. Habermehl, PE Hammann, HC Krebs, W. Ternes: "Naturstoffchemie An Introduction", Volume 1, 3rd edition . Springer-Verlag, Heidelberg 2008, ISBN 978-3-540-73732-2 , p. 660 .