| CPC A61K 8/068 (2013.01) [A61K 8/345 (2013.01); A61K 8/671 (2013.01); A61K 8/92 (2013.01); A61Q 19/08 (2013.01); A61K 2800/10 (2013.01); A61K 2800/413 (2013.01); A61K 2800/524 (2013.01); B82Y 5/00 (2013.01)] | 15 Claims |
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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.
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