Magnesium Ascorbyl Phosphate

What is magnesium ascorbyl phosphate?

Magnesium ascorbyl phosphate is a derivative of vitamin C, ascorbic acid. It is produced by chemical modification of ascorbic acid; specifically, by introducing a phosphate group into the enediol system at the 2-position (R).

When used as an active ingredient in cosmetic formulations, its concentration is usually around 1-2%, and when used as an antioxidant to stabilize formulations, its concentration ranges from 0.05-0.1% in general (R).

Is magneisum ascorbyl phosphate stable?

Because ascorbic acid is an unstable molecule that can be impractical to formulate for topical use, derivatives such as magneisum ascorbyl phosphate have been utilized in many topical formulations (R). Chemically, magneisum ascorbyl phosphate is more stable than ascorbic acid - the phosphate group in the 2-position seems to protect its enediol system from hydrolysis. A solution of 1% magneisum ascorbyl phosphate experienced only small concentration losses of 5% and 17% after 60 days of storage at room temperature and at 42°C, as compared to 1% ascorbic acid and 1% ascorbyl palmitate, which lost 63% and 100%, and 23% and 53% respectively, under the same conditions (R). The shelf life of an emulsion formulation containing magneisum ascorbyl phosphate has been estimated to be 200 days (R).

Does magnesium ascorbyl phosphate get absorbed?

In a study on human skin, magnesium ascorbyl phosphate was absorbed from a cream base into the epidermis and dermis, but the percutaneous penetration was low, with only 1.6% detected 48 hours after application. This was improved by the addition of 1% or 3% 1,1-methyleneglycol-bis to the formulation (R).

Laser pre-treatment of the skin has also been shown to enhance the skin permeation and hence topical delivery of vitamin C and its derivatives, including magnesium ascorbyl phosphate, through reducing the thickness of the strateum corneum. The transdermal flux of magnesium ascorbyl phosphate across intact skin is comparable with that of ascorbic acid (R), but increases by 48-123-fold if the skin is pretreated with a erbium:yttrium-aluminum-garnet (Er:YAG) laser, and 116-156-fold if the skin is pretreated with a carbon dioxide laser (R, R).

Lauroyl/palmitoyl glycol chitosan gels also enhance the sustained release and the skin penetration and deposition of magnesium ascorbyl phosphate compared to other vehicles such as glycol chitosan, hydroxypropylmethylcellulose, and carbopol. Moreover, the epidermal to dermal drug deposition ratio tends to increase with the increase in polymer concentration, which is beneficial to the activity of magnesium ascorbyl phosphate in the epidermis, including the inhibition of tyrosinase and protection from UV damage (R).

The characteristics of the formulation play a very important role in the skin bioavailability of magnesium ascorbyl phosphate, as a commercial serum containing 13% magnesium ascorbyl phosphate failed to increase the skin levels of ascorbic acid when applied on pigs (R).

What happens after magnesium ascorbyl phosphate is absorbed?

Magnesium ascorbyl phosphate is converted to ascorbic acid, the biologically active form of vitamin C, by phosphatase enzymes in the skin as it crosses the epidermis (R).