Color stable skin benefit compositions
Nanoemulsions as emulsion additives are prepared to stabilize actives and prevent formulation discoloration. The nanoemulsions have at least 30% by weight oil and are suitable to add to emulsions and/or structured water to produce color stable end use skin benefit compositions.
1 . A method for improving color stability of an end use composition by reducing discoloration originating from active comprising 4-ethyl resorcinol, 4-hexyl resorcinol or both, and retinyl propionate, retinol or both present in the end use composition, the method comprising the steps of:
a) preparing a water continuous nanoemulsion by mixing with homogenization at a pressure from 1,500 to 6,000 psi (a) the active; (b) water; (c) water soluble humectant (d) oil; and (e) emulsifier, wherein:
i) the active is soluble in the oil;
ii) oil as particle in the nanoemulsion has a particle size from 0.05 to less than 1.5 microns; and
iii) the nanoemulsion comprises at least 30% by weight oil;
b) combining the nanoemulsion with an emulsion chassis, the emulsion chassis being water continuous; and
c) shearing the nanoemulsion and emulsion chassis after combining to produce the end use composition; and
d) recovering the end use composition, wherein the nanoemulsion makes up from 25 to 60% by weight of the end use composition and the end use composition is water continuous.
2 . The method according to claim 1 wherein the end use composition is a cream, lotion, balm, or serum.
3 . The method according to claim 1 wherein the active comprises retinyl propionate and 4-hexyl resorcinol.
4 . The method according to claim 1 wherein the active consists essentially of retinyl propionate and 4-hexyl resorcinol.
5 . The method according to claim 1 wherein the end use composition further comprises vitamin B2, niacinamide, vitamin B6, vitamin C, vitamin E, tocopherol acetate, folic acid, biotin, vitamin D, vitamin K, DL-panthenol or a mixture thereof.
6 . The method according to claim 1 wherein the end use composition further comprises alpha hydroxy acid, beta hydroxy acid, 12-hydroxystearic acid, petroselinic acid, conjugated linoleic acid, creatine, creatinine, retinoid booster, sunscreen or a mixture thereof.
7 . The method according to claim 6 wherein the end use composition does comprise retinoid booster and the retinoid booster is climbazole, bifonazole, farnesole, glycyrrchetinic acid, ursolic acid, geranyl geraniol, oleyl betaine, hexanoyl sphingosine or a mixture thereof.
8 . The method according to claim 1 wherein the end use composition further comprises iodopropynyl butyl carbamate, phenoxyethanol, hydoxyacetophenone, 1,2-octanediol, ethylhexylglycerine, hexylene glycol, or a mixture thereof.
9 . The method according to claim 1 wherein the end use composition has a pH from 6 to 7.5 and a viscosity from 5 to 20,000 cps.
10 . The method according to claim 1 wherein the emulsifier has an HLB from 7 to 17 and the nanoemulsion comprises from 1 to 35% by weight humectant comprising glycerine.
11 . The method according to claim 1 wherein the end use composition comprises glycerin, 4-hexyl resorcinol and retinol, and further comprises 1,2-octanediol, ethylhexylglycerin, phenoxyethanol, cetyl alcohol, propylene glycol, 1,3 butylene glycol, or a mixture thereof.
12 . An end use composition made by the method of claim 1 .
13 . The method according to claim 3 wherein the end use composition further comprises niacinamide, vitamin K or both.
14 . The method according to claim 3 wherein the end use composition further comprises 12-hydroxystearic acid.
15 . The end use composition according to claim 12 wherein the end use composition comprises niacinamide, retinyl propionate and 4-hexyl resorcinol.