Sodium Ascorbyl Phosphate is a chemical compound, the sodium salt of ascorbic acid 2-phosphate, is a strong antioxidant with ascorbic acid-like properties and exerts a strong biological contrast in cells against reactive oxygen radicals in excess.

The name defines the structure of the molecule:

• Sodium refers to the sodium ions (Na+) present in the compound. Sodium is a chemical element belonging to the alkali metal group.
• Ascorbyl refers to the ascorbate ion, which is a form of vitamin C (ascorbic acid).
• Phosphate refers to the phosphate group (PO₄^3-), which is a polyatomic ion with a charge of -3.

The synthesis process takes place in different steps:

• Phosphorylation of ascorbic acid. Ascorbic acid is reacted with a phosphorylating agent, such as phosphorus oxychloride or phosphorus pentoxide, to introduce a phosphate group, forming ascorbyl phosphate.
• Neutralisation: ascorbyl phosphate is then neutralised with sodium hydroxide (NaOH) to form sodium ascorbyl phosphate.

Medical

The results of this study suggest that hyaluronic acid cross-linked with urea and Sodium Ascorbyl Phosphate have demonstrated anti-inflammatory activity and act in combination to accelerate wound healing. Therefore, it could be a potential adjuvant in anti-inflammatory nasal formulations (1).

Acne vulgaris is the most common inflammatory skin disorder and jeopardizes seriously the facial impression of a person. Vitamin C tends to break down in cosmetic formulations resulting in a brownish discoloration. Sodium ascorbyl phosphate (SAP) represents a stable precursor of vitamin C that ensures a constant delivery of vitamin C into the skin.  In conclusion, these data show that SAP is efficient in the prevention and treatment of acne vulgaris. SAP can be used in a non-antibiotic and effective treatment or co-treatment of acne with no side effects, which makes it particularly attractive for cosmetic purposes (2).

Based on results of this study, it could be concluded that the bleaching agents used in the present study (with or without sodium ascorbyl phosphate) did not affect human enamel hardness and that sodium ascorbyl phosphate is able to reverse the compromised bonding in bleached human enamel (3).

Cosmetics

Antioxidant agent. Ingredient that counteracts oxidative stress and prevents cell damage. Free radicals, pathological inflammatory processes, reactive nitrogen species and reactive oxygen species are responsible for the ageing process and many diseases caused by oxidation.

Sodium Ascorbyl Phosphate studies

• Molecular Formula: C₆H₆Na₃O₉P
• Molecular Weight: 322.05 g/mol
• CAS: 66170-10-3
• UNII 836SJG51DR
• EC Number: 425-180-1
• MDL number  MFCD03095479
• NACRES:  NA.79

Synonims: 

• 2-Phospho-L-ascorbic acid trisodium salt
• Sodium L-ascorbyl-2-phosphate
• L-Ascorbic acid 2-phosphate trisodium salt
• ascorbate-2-phosphate
• sodium (R)-5-((S)-1,2-dihydroxyethyl)-2-oxido-4-oxo-4,5-dihydrofuran-3-yl phosphate
• ascorbic acid 2-phosphate
• Trisodium (R)-5-((S)-1,2-dihydroxyethyl)-4-oxido-2-oxo-2,5-dihydrofuran-3-yl phosphate
• ascorbyl-2-monophosphate
• Trisodium ascorbate-2-phosphate
• ascorbyl-2-phosphate

References________________________________________________________

(1) Fallacara A, Busato L, Pozzoli M, Ghadiri M, Ong HX, Young PM, Manfredini S, Traini D. In vitro characterization of physico-chemical properties, cytotoxicity, bioactivity of urea-crosslinked hyaluronic acid and sodium ascorbyl phosphate nasal powder formulation. Int J Pharm. 2019 Mar 10;558:341-350. doi: 10.1016/j.ijpharm.2019.01.012.

(2) Klock J, Ikeno H, Ohmori K, Nishikawa T, Vollhardt J, Schehlmann V. Sodium ascorbyl phosphate shows in vitro and in vivo efficacy in the prevention and treatment of acne vulgaris. Int J Cosmet Sci. 2005 Jun;27(3):171-6. doi: 10.1111/j.1467-2494.2005.00263.x.

Abstract. Acne vulgaris is the most common inflammatory skin disorder and jeopardizes seriously the facial impression of a person. Development of acne involves a complex relation among several causes. Treatment and prevention success can be archived by affecting the main contributors positively like Proprionibacterium acnes or lipid oxidation leading to inflammatory reactions and follicular keratinization. Vitamin C tends to break down in cosmetic formulations resulting in a brownish discoloration. Sodium ascorbyl phosphate (SAP) represents a stable precursor of vitamin C that ensures a constant delivery of vitamin C into the skin. We were able to show that 1% SAP has a strong antimicrobial effect with a log reduction of 5 after 8 h on P. acnes in a time-kill study. Further on in a human in vivo study with 20 subjects an SAP O/W formulation significantly prevents the UVA-induced sebum oxidation up to 40%. Finally, we performed an open in vivo study with 60 subjects with a 5% SAP lotion over 12 weeks. The efficacy ranked as excellent and good of SAP was 76.9%, which was superior compared with a widely prescribed acne treatment. In conclusion, these data show that SAP is efficient in the prevention and treatment of acne vulgaris. SAP can be used in a non-antibiotic and effective treatment or co-treatment of acne with no side effects, which makes it particularly attractive for cosmetic purposes.

(3) da Silva AP, Lima AF, Cavalcanti AN, Marchi GM. Effects of 3% sodium ascorbyl phosphate on the hardness and bond strength of human enamel bleached with 10% carbamide peroxide. Gen Dent. 2010 Jul-Aug;58(4):e174-8.

Abstract. For this study, 120 fragments obtained from human third molars were randomly separated into 12 groups (n = 10). Four groups were used for measuring the Knoop hardness number (KHN) of enamel, while the other eight were used for testing the microtensile bond strength (muTBS) of two adhesive systems (Single Bond and Prime & Bond NT). All groups presented statistically similar KHN values. According to bond strength results, bleached enamel without antioxidant application demonstrated the lowest values of all groups. Based on these results, it could be concluded that the bleaching agents used in the present study (with or without sodium ascorbyl phosphate) did not affect human enamel hardness and that sodium ascorbyl phosphate is able to reverse the compromised bonding in bleached human enamel.