α-arbutin, the scientific name 4-hydroxyphenyl-α-glucopyranoside, as a cosmetic additive, has the effects of whitening, freckle removal, and skin rejuvenation, and wrinkle removal. Studies have shown that the whitening effect of α-arbutin is about 10 times that of its isomer β-arbutin, and it has higher safety. α-Arbutin has been widely used by many well-known cosmetic brands in the world.
Stability of α-Arbutin
Hydroquinone can be detected in 0.9% α-arbutin aqueous solution under pH 1.0, 13.0, or ultraviolet (UV) irradiation conditions; α-arbutin has good high-temperature tolerance when the temperature reaches about 100 ℃, Hydroquinone was not detected in 0.9% α-arbutin aqueous solution. The half-life of 3.3% α-arbutin in citric acid-sodium phosphate buffer was measured at pH 3.5, 4.9, 5.5, 6.5, and 40 ℃. The glycosides are the most stable, with a half-life of about 77 months.
The stability study of α-arbutin in cosmetic matrix raw materials shows that α-arbutin in surfactant Tween 80, fatty alcohol polyoxyethylene ether sulfate (AES), fatty alcohol polyoxyethylene ether (AEO9) has good stability in the solution of humectant glycerol and metal ions (copper ion, magnesium ion), and no hydroquinone is detected; but in the preservative methylparaben, the stability is poor, and the mass fraction of hydroquinone produced by decomposition was 4.45%. However, the stability of α-arbutin in the mixed solution of the basic raw materials methylparaben, fatty alcohol polyether-20, K12-Na, glycerin, and metal copper ions is good, and no hydroquinone is detected. This may be due to the existence of glycerol or fatty polyether-20, which provides a relatively stable environment for α-arbutin.
The basic formula products containing 2% α-arbutin were placed at pH 5, 6 and 5, 25, and 40 ℃ for 1 week, 6 weeks, and 3 months, respectively, and the hydroquinone was detected. The results showed that the detected concentration increased with the increase of temperature, but was not affected by pH; after 1 week at 40 ℃, the content of hydroquinone was 13-18 mg/kg, and after 3 months, it was 43-48 mg/kg. However, the stability of α-arbutin in different types of formulas is different. It is stable in a cream (containing α-arbutin 0.15% to 1.68%) at room temperature for 16 months, and the stability is good; but α-arbutin is Unstable in serum (containing 2.1% alpha-arbutin), 7.6% loss of alpha-arbutin after 16 months of storage.
What are the side effects of alpha arbutin?
α-Arbutin is mainly an effect that can inhibit melanin production and lighten pigmentation. It is mainly used for pigmented skin diseases, such as freckles, chloasma, and melanosis, and can lighten the melanin deposition of the skin. Most patients have very low side effects, and generally, these adverse reactions will gradually dissipate after suspending the use. Most people are using arbutin, and the side effects are relatively few or mild. The common adverse reactions are slight tingling or itching of the skin, and redness and swelling may occur in a slightly severe form.
In its latest opinion, the European Union's Scientific Committee on Consumer Safety (SCCS) stated that alpha-arbutin is safe when it is present in no more than 2% of facial care products and no more than 0.5% in body care products.
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