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.An alternate spelling, retinol palmitate, which violates the -yl organic chemical naming convention for esters, is also frequently seen. Biology
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. The esters are also intermediates in the visual cycle: RPE65 isomerizes the retinyl part to 11-cis-retinal. Uses
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).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.Retinyl palmitate is also a constituent of some topically applied skin care products.
Nexafed is a formulation of pseudoephedrine developed by Acura Pharmaceuticals used to deter the use of the pseudoephedrine contained in the product for illicit methamphetamine synthesis. Nexafed uses a polymer matrix that forms a thick gel when hydrated, preventing the extraction of pseudoephedrine. Nexafed is the only meth-resistant formulation of pseudoephedrine that shows therapeutic equivalence to Sudafed.It is sold at various pharmacies in the US, including Fruth Pharmacy and Kroger, particularly in communities where illicit methamphetamine production is an issue. References


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