United States Patent:  5,976,555

Assignee:  Johnson & Johnson Consumer Products, Inc. (Skillman, NJ)

Filed:  March 1, 1996

Skin care compositions comprising an oil-in-water emulsion base containing retinoids and possessing good physical and chemical stability. More particularly, said skin care compositions contain (a) an emulsifier system selected from the group consisting of: (i) a mixture of glyceryl stearate and polyethylene glycol 100 stearate; (ii) cetearyl alcohol and cetearyl glucoside; (iii) a mixture of a polyethylene glycol ethers of stearyl alcohol; and (iv) a mixture of sorbitan stearate and polysorbate 60; (b) a co-emulsifier selected from the group consisting of cetyl alcohol, stearyl alcohol and mixtures thereof; (c) an oil phase present in the amount of from about 5 to about 20 percent by weight of the total emulsion composition which contains (i) a light, dry absorbable oil and (ii) substantive, emollient oils or waxes, wherein the light, dry absorbable oil and the substantive oil or wax are present in a ratio of from about 1:3 for about 10:1.

SUMMARY OF THE INVENTION

In accordance with the present invention, it has now been unexpectedly found that certain retinoids may be successfully stabilized against chemical degradation by incorporating them into oil-in-water emulsions comprising a specifically defined stabilizing system. In addition, this invention relates to oil-in-water emulsion compositions which are cosmetically elegant.

The retinoids which can be stabilized against chemical degradation in accordance with the principles of the present invention are retinol (Vitamin A alcohol), retinal (Vitamin A aldehyde), retinyl acetate, retinyl palmitate and mixtures thereof. It is also theorized that other retinoids, including synthetic retinoids and retinoid-like chemicals may benefit from inclusion in the formulations of this invention.

As used herein, the "chemical stability" or "stability" of a retinoid is defined in terms of the percentage of the specified retinoid which is retained in its original chemical form after the composition has been stored for a specified period of time at a specified temperature. Thus, if the original concentration of all-trans retinol in an absolute ethanol solution were 0.20% by weight and, after two (2) weeks' storage at room temperature (21^oC..+-.1^oC.), the concentration of all-trans retinol were 0.18% by weight, then the original solution would be characterized as having a chemical stability of 90% after two weeks' storage at room temperature. In the same fashion, if an emulsion comprising all-trans retinol had an initial concentration of 0.30% by weight and after storage for 13 weeks at 40^o C. had a concentration of all trans-retinol of 0.24% by weight, then the original emulsion retinol of 80% after 13 weeks storage at 40^oC.

Specifically, a commercially usable composition should exhibit a stability of at least about 60% of the active retinoid(s) after 13 weeks storage at 40^oC. Preferably, the compositions of this invention exhibit a stability of at least about 70% after 13 weeks' storage at 40^oC.

Accordingly, there is provided, in accordance with the teachings of this invention, a skin care composition comprising an oil-in-water emulsion and a retinoid selected from the group consisting of retinol, retinal, retinyl acetate, retinyl palmitate and mixtures thereof, said composition having a pH of between about 4 and about 10; said composition further comprising an oil phase, said oil phase having a relatively low level of unsaturation; said composition further comprising a stabilizing system selected from the group consisting of:

a) at least one oil-soluble antioxidant;

b) a chelating agent and at least one oil-soluble antioxidant;

c) a chelating agent; and

d) a chelating agent and an antioxidant present in each of the oil and water phases of said emulsion;

said composition retaining at least about 70% of said retinoids after 13 weeks' storage at 40^oC.

Additionally, there are provided herein oil-in-water emulsions having novel emulsification systems. The oil-in-water emulsion compositions of this invention preferably contain:

a) an emulsifier system selected from the group consisting of:

i) a mixture of glyceryl stearate and polyethylene glycol 100 stearate;

ii) cetearyl alcohol and cetearyl glucoside;

iii) a mixture of a polyethylene glycol ether of stearyl alcohol of the formula:

CH₃ (CH₂)₁₆ CH₂ (OCH₂ CH₂)_n OH

wherein n is 21 and a polyethylene glycol ether of stearyl alcohol of the formula:

CH₃ (CH₂)₁₆ CH₂ (OCH₂ CH₂)_n OH

wherein n is 2; and

iv) a mixture of sorbitan stearate and polysorbate 60 (a mixture of stearate esters of sorbitol and sorbitol anhydrides condensed with 20 moles of ethylene oxide);

b) a co-emulsifier selected from the group consisting of: cetyl alcohol, stearyl alcohol and mixtures thereof;

c) an oil phase present in the amount of from about 2 to about 20 percent by weight of the total emulsion composition comprising:

i) a light, dry absorbable oil and

ii) substantive, emollient oils or waxes

wherein such dry absorbable oil and such substantive emollient oil are present in a ratio of from about 1:3 to about 10:1.

Claim 1 of 37 Claims

1. A topical oil-in-water emulsion composition comprising:

a) an emulsifier system selected from the group consisting of:

i) a mixture of glyceryl stearate and polyethylene glycol 100 stearate;

ii) cetearyl alcohol and cetearyl glucoside;

iii) a mixture of a polyethylene glycol ether of stearyl alcohol of the formula:

CH₃ (CH₂)₁₀ CH₂ (OCH₂ CH₂)_n OH

Wherein n is 21 and a polyethylene glycol ether of stearyl alcohol of the formula:

CH₃ (CH₂)₁₆ CH₂ (OCH₂ CH₂)_n OH

Wherein n is 2; and

iv) a mixture of sorbitan stearate and polysorbate 60 (a mixture of stearate esters of sorbitol and sorbitol anhydrides condensed with 20 moles of ethylene oxide);

b) a co-emulsifier selected from the group consisting of: cetyl alcohol, stearyl alcohol and mixtures thereof;

c) an oil phase present in the amount of from about 2 to about 20 percent by weight of the total emulsion composition comprising:

i) a light, dry absorbable oil and

ii) substantive, emollient oils or waxes

wherein said light dry absorbable oil and said substantive oil or wax are present in a ratio of from about 1:3 to about 10:1;

d) a retinoid;

said composition having a pH of from about 4 to about 10.

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