United States Patent:   6,022,547

Assignee:  Helene Curtis, Inc. (Chicago, IL)

Filed:  June 28, 1996

Rinse-off, water-in-oil-in-water multiple emulsion compositions are disclosed. The multiple emulsion compositions comprise an external aqueous phase optionally incorporating an emulsifier and/or a second topically-active compound. The internal phase comprises a primary water-in-oil emulsion, wherein the primary emulsion comprises a first topically-active compound, a surfactant phase, an oil phase, and water.

SUMMARY OF THE INVENTION

The present invention is directed to rinse-off, topically-effective W₁ -O-W₂ multiple emulsion compositions having improved efficacy, and to methods of using the W₁ -O-W₂ multiple emulsion compositions. More particularly, the present invention is directed to a W₁ -O-W₂ multiple emulsion composition comprising a continuous external aqueous phase (W₂) and a primary water-in-oil (W₁ /O) emulsion as the dispersed internal phase.

The primary W₁ /O emulsion comprises a first topically-active compound, like a hair conditioner, a hair dye, a hair fixative, a skin care compound or a topical medicament; a surfactant phase comprising silicon-free surfactant or surfactant blend having an HLB value of about 10 or less, an oil-soluble silicon-based surfactant, an oil-soluble polymeric surfactant or a mixture thereof; an oil phase comprising a silicone compound or a hydrocarbon compound; and water. The external phase comprises water, and preferably a second topically-active compound and/or an emulsifier, such as a nonionic surfactant having an HLB value of greater than about 10 or a surfactant system capable of forming stabilizing liquid crystals.

The "HLB value", or hydrophobic-lipophilic balance value, of a surfactant is a term well-known to those skilled in the art. The HLB value is related to the solubility of the surfactant, wherein a surfactant with a low HLB value, e.g., about 10 or less, tends to be oil soluble and a surfactant with a high HLB value, e.g., greater than about 10, tends to be water soluble.

In particular, the W₁ -O-W₂ multiple emulsion compositions comprise:

(a) about 40% to about 99% by weight of the composition of an external aqueous phase (W₂); and

(b) about 1% to about 60% by weight of the composition of a primary W₁ /O emulsion.

The primary W₁ /O emulsion comprises:

(a) about 1% to about 95% by weight of the primary emulsion of an aqueous phase comprising (i) a first topically-active compound and (ii) water;

(b) about 0.5% to about 95% by weight of the primary emulsion of an oil phase comprising a volatile silicone compound, a nonvolatile silicone compound, a volatile hydrocarbon compound, a nonvolatile hydrocarbon compound, or a mixture thereof; and

(c) about 0.1% to about 20% by weight of the primary emulsion of a surfactant phase comprising a silicon-free surfactant or surfactant blend having an HLB value of about 10 or less, an oil-soluble silicon-based surfactant, an oil-soluble polymeric surfactant, or a mixture thereof.

The external aqueous phase (W₂) optionally includes (a) an emulsifier, such as a nonionic surfactant having an HLB value of greater than about 10 or a surfactant system capable of forming stabilizing liquid crystals and/or (b) a second topically-active compound which can perform the same or a different function from the first topically-active compound. The external aqueous phase is free of a polymeric gelling agent, such as a polyacrylic acid.

A W₁ -O-W₂ multiple emulsion composition of the present invention can be a liquid composition having a viscosity of about 1 cps to about 15,000 cps (centipoise), and preferably about 100 to about 10,000 cps. To achieve the full advantage of the present invention, a liquid topically-effective composition has a viscosity of about 1,000 to about 9,000 cps.

The W₁ -O-W₂ multiple emulsion also can be cream-like and have a viscosity of about 50,000 to about 1,200,000 cps, and preferably about 100,000 to about 1,000,000 cps. A W₁ -O-W₂ composition having a cream-like consistency is free of a polymeric gelling agent in the external phase.

The W₁ -O-W₂ multiple emulsion compositions of the present invention are rinse-off compositions, which are designed for application to the skin or hair, followed by rinsing from the skin or hair. The second topically-active compound, if present in the external aqueous phase, performs its intended function during and after topical application of the composition to the skin or hair, then is rinsed from the skin or hair. The droplets of the primary W₁ /O emulsion are of sufficient size, i.e., a range of about 5 to about 1000.mu. (microns), and preferably about 10 to about 500.mu., in diameter, to resist removal from the skin or hair during the rinsing step. The droplets of the internal W₁ phase of the W₁ /O primary emulsion range in size from about 1 to about 75.mu..

The external oil phase of the primary W₁ /O emulsion then evaporates during drying of the skin or hair to release the first topically-active compound present in the internal aqueous phase of the primary emulsion. Alternatively, the internal aqueous phase is released by rubbing the skin or hair to break the W₁ /O primary emulsion. The first topically-active compound then can contact the skin or hair to perform its intended function. In another embodiment, the primary W₁ /O emulsion is not broken, but is allowed to remain on the skin or hair as is. Typically, the first topically-active compound is not rinsed from the skin or hair.

In accordance with an important aspect of the present invention, a water-soluble (or water-dispersible), topically-active compound therefore is included in a rinse-off composition without wasting a substantial amount of the topically-active compound during the rinsing step.

Another important aspect of the present invention is the ability to treat the skin or hair with incompatible water-soluble, topically-active compounds using a single W₁ -O-W₂ multiple emulsion composition. By incorporating the first topically-active compound in the internal aqueous phase of the primary emulsion (W₁) and the second topically-active compound in the external aqueous phase of the composition (W₂), the oil phase (O) provides a barrier that separates the two incompatible topically-active compounds and precludes contact between the compounds. Incompatible topically-active compounds therefore can be applied to the hair or skin from a single composition, as opposed to applying the topically-active compounds individually from two different compositions.

For example, it is well known that an anionic compound, like an anionic surfactant, and a cationic compound, like a quaternary ammonium compound, are incompatible. However, these incompatible compounds can be included in the present W₁ -O-W₂ multiple emulsion compositions.

The anionic surfactant is present as the second topically-active compound in the external aqueous phase (W₂). Upon application to the hair, the anionic surfactant cleanses the hair, then is rinsed from the hair. The primary W₁ /O emulsion, which incorporates the quaternary ammonium compound (i.e., the first topically-active compound) in the aqueous phase, is not rinsed from, but remains on, the hair. An oil phase provides conditioning benefits to the wet hair, and evaporates during hair drying to release the quaternary ammonium compound, which is substantive to, and further conditions, the hair. Similarly, a cationic compound can be the second topically-active compound to condition the hair and an anionic hair dye can be the first topically-active compound to dye the hair.

In accordance with another important aspect of the present invention, the first topically-active compound is water soluble or water dispersible. The first topically-active compound therefore can be rinsed from the skin or the hair during a subsequent shampooing or rinsing to preclude an undesirable residue of first topically-active compound building up on the hair.

In another embodiment of the present invention, the first and second topically-active compounds are compatible, yet perform different functions. For example, the second topically-active compound can be a cleansing compound for the skin or hair, and the first topically-active compound can be a topical medicament, a hair fixative, or a hair dye, for example, designed to remain on the skin or hair.

In another important embodiment, the external aqueous phase does not include a second topically-active compound. In this embodiment, the first topically-active compound in the primary W₁ /O emulsion is precluded from contacting the skin or hair until desired. For example, present day water-soluble hair dye compositions stain the hands of the applicator, sinks and countertops. The present W₁ -O-W₂ multiple emulsion compositions allow application of a water-soluble dye to hair from a rinse-off product, wherein the dye is released only after the composition is applied to the hair, and the hair is rinsed and dried. Staining of hands, sinks and countertops therefore is avoided. Composition economics also is enhanced because the water-soluble hair dye, a relatively expensive ingredient, is not rinsed from the hair and wasted.

In yet another important embodiment, a W₁ -O-W₂ multiple emulsion composition of the present invention incorporates a cleansing agent as the second topically-active compound and an astringent salt as the first topically-active compound to form a stable and efficacious deodorant-cleanser composition. In other embodiments of the present invention, the first topically-active compound is a topically-effective drug or medicament; a topical anesthetic; a sunscreen agent; a skin care agent; a skin-soothing emollient or other topical cosmetic compound; a topical anti-inflammatory; and the like.

The first topically-active compound incorporated into the multiple emulsion compositions of the present invention preferably is water soluble and is incorporated into the aqueous phase of the primary W₁ /O emulsion. As used herein, the term "water soluble" means "water soluble or water dispersible". However, water-insoluble topically-active compounds also can be incorporated into the oil phase of the primary W₁ /O emulsion.

In a preferred embodiment, the W₁ -O-W₂ multiple emulsion compositions comprise:

(A) about 50% to about 95% by weight of the composition of an external aqueous phase, said external aqueous phase comprising:

(i) about 0.1% to about 30% by weight of the external aqueous phase of a second topically-active compound;

(ii) about 0.1% to about 10% by weight of the external aqueous phase of an emulsifier; and

(iii) water;

(B) about 5% to about 50% by weight of the composition of a primary water-in-oil emulsion, said primary emulsion comprising:

(i) about 10% to about 95% by weight of the primary emulsion of an aqueous phase, said aqueous phase comprising (a) water and (b) a topically-effective amount of a first topically-active compound, typically about 0.1% to about 30% by weight based on the total weight of the primary emulsion;

(ii) about 0.5% to about 80% by weight of the primary emulsion of an oil phase comprising a volatile silicone compound, a volatile hydrocarbon compound, or a mixture thereof; and

(iii) about 0.1% to about 15% by weight of the primary emulsion of a surfactant phase comprising a silicon-free surfactant or surfactant blend having an HLB value of about 1 to about 7, an oil-soluble silicon-based surfactant, an oil-soluble polymeric surfactant or a mixture thereof.

Other aspects of the present invention include providing a phase stable, topically-effective composition, which is free of polymeric gelling agents in the external aqueous phase, for the administration of one or more water-soluble, topically-active compounds from a rinse-off product by providing a primary W₁ /O emulsion having a droplet size of about 5 to about 1000.mu..

The present W₁ -O-W₂ multiple emulsion compositions are stable over extended storage periods, can be essentially nonstaining, effectively deliver one or more water-soluble, topically-active compounds to the skin and hair, and exhibit excellent esthetic and functional properties for consumer acceptance.

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