Stabilizing vitamin C topical formulations
Topical formulations of L-ascorbic acid dissolved in a combination of a urea agent and a non-aqueous skin-compatible solvent are provided. The formulations are storage stable for an extended period of time without significant degradation of the L-ascorbic acid in the composition, are have desirable physical properties. The topical formulations can include high concentrations of the L-ascorbic acid. The topical formulations can include cinnamic acid or derivatives thereof as a penetration enhancer and stabilizing component of ascorbic acid. Topical compositions of this disclosure find use in treating or preventing a variety of cosmetic and/or dermatological conditions as well as to reduce the appearance of chronological and/or environmentally-caused skin aging.
1. A storage stable topical composition comprising:
a. 16% to 20% by weight ascorbic acid;
b. 5 to 10% by weight of a solubility and penetrating agent that is a urea agent;
c. 0.1% to 1% by weight of ferulic acid; and
d. less than 10% by weight in total of one or more optional additional components;
e. dissolved in a non-aqueous skin-compatible solvent comprising 1,3-propanediol; wherein the ascorbic acid is dissolved at a concentration (AA) that is above its maximum concentration in the solvent alone (X), and the urea agent is dissolved at a concentration that is (AA−X)*1.25;
wherein the composition is substantially free of water, and wherein the composition does not comprise niacinamide.
2. The composition of claim 1 , wherein the composition demonstrates less than 10 mol % degradation of the ascorbic acid after storage for 6 weeks at 40° C.±2° C. in a sealed container.
3. The composition of claim 1 , wherein the urea agent is urea, hydroxyethyl urea, or a mixture of urea and hydroxyethyl urea.
4. The composition of claim 1 , wherein the solvent further comprises 1,2 propanediol, 1,3 butanediol, 1,5 pentanediol, 1,2 hexanediol, 1,6 hexanediol, 1,2 hexanediol, glycerol, diglycerol, ethoxydiglycol, dimethyl isosorbide, or any combination thereof.
5. The composition of claim 4 , wherein the solvent further comprises 1,2 hexanediol.
6. The composition of claim 1 , wherein the one or more optional additional components are selected from tocopherols, tocotrienols, azelaic acid, hydroxy acids, panthenol, Pinus pinaster bark extract, emulsifying agent, hyaluronic acid complex, madecassoside, acetyl zingerone, bakuchiol, and bis-ethylhexylhydroxydimethoxybenzylmalonate.
7. The composition of claim 6 , wherein the composition comprises:
20% by weight ascorbic acid;
10% by weight urea agent;
0.5% by weight ferulic acid;
69% by weight 1,3-propanediol; and
0.5% by weight in total of diglycerin and Pinus pinaster bark extract.
8. The composition of claim 6 , wherein the composition comprises:
20% by weight ascorbic acid;
10% by weight urea agent; and
0.5% by weight ferulic acid; and
the solvent consists of 1,3-propanediol.
9. The composition of claim 6 , wherein the composition consists of:
20% by weight ascorbic acid;
10% by weight urea agent;
0.5% by weight ferulic acid;
69% by weight 1,3-propanediol; and
0.5% by weight in total of diglycerin and Pinus pinaster bark extract;
wherein the composition is substantially free of water, and wherein the composition does not consist of niacinamide.
10. The composition of claim 1 , wherein the composition comprises 20% by weight of ascorbic acid.
11. The composition of claim 1 , wherein the ratio by weight of ascorbic acid to urea agent is 2 to 1.
12. The composition of claim 1 , wherein the composition comprises at least 60% by weight of the solvent comprising 1,3-propanediol.
13. The composition of claim 1 , wherein the composition comprises 10% by weight urea.
14. The composition of claim 1 , wherein the composition comprises 0.5% by weight of diglycerin and Pinus pinaster bark extract.
15. The composition of claim 1 , wherein the ratio by weight of ascorbic acid to urea agent is between 3 and 3.5.
16. The composition of claim 1 , wherein the optional additional component comprises azelaic acid.
17. The composition of claim 16 , wherein the composition comprises 3% to 10% by weight of the azelaic acid.
18. The composition of claim 1 , wherein the one or more optional additional components comprises 2% or less by weight of Pinus pinaster bark extract.
19. The composition of claim 1 , wherein the optional additional component is hydroxy acid is selected from glycolic acid, lactic acid, mandelic acid, salicylic acid, capryloyl salicylic acid, salicyloyl phytosphingosine, gluconolactone, lactobionic acid, maltobionic acid, and combinations thereof.
20. An emulsion composition, comprising:
the composition of claim 1 ;
an oil component; and
an optional emulsifying agent.
21. The composition of claim 1 , wherein the composition does not comprise vitamin E acetate.
22. The composition of claim 1 , wherein the composition does not consist of niacinamide.
23. A storage stable topical composition comprising:
20% by weight ascorbic acid;
urea, wherein the ratio by weight of ascorbic acid to urea is 1.8 to 2.2;
0.1% to 1% by weight of ferulic acid; and
less than 1% by weight in total of Pinus pinaster bark extract;
dissolved in a non-aqueous solvent comprising 60% to 75% by weight of 1,3-propanediol;
wherein the composition is substantially free of water, and wherein the composition does not comprise niacinamide.
24. The composition of claim 23 , wherein the composition consists essentially of:
20% by weight ascorbic acid;
10% by weight urea;
0.5% by weight ferulic acid;
less than 1% by weight in total of Pinus pinaster bark extract; and
1,3-propanediol.