Drug – bio-affecting and body treating compositions – Face or body powders for grooming – adorning – or absorbing
Reexamination Certificate
1999-11-23
2001-09-18
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Face or body powders for grooming, adorning, or absorbing
C424S401000, C424S489000, C424S490000, C424S497000
Reexamination Certificate
active
06290941
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to cosmetic and pharmaceutical compositions. More specifically, the invention relates to powder compositions that convert to liquid on the skin.
BACKGROUND OF THE INVENTION
Powder cosmetic and skin care compositions are well-known and widely used for a variety of purposes. Normally, they are composed of a combination of different types of small particles that perform a number of different functions in the products in which they are used, and can particularly contribute to ease of application of pigments to the face. For this reason, powders are particularly favored in color cosmetics for eyeshadows, blushers, and eyebrow products; however, they are also used widely in personal care products as dusting and baby powders, for foot care and hair care, and as a base for a variety of medicated products. From a functional point of view, one of their major advantages is their ability to absorb water, thereby assisting in drying damp or perspiring skin, as well as being able to absorb excess sebum from the skin or hair. Although widely used, and largely effective for the intended purposes, there are some drawbacks to the use of powder. By nature, powders tend to scatter, and may not remain in place after application. In addition, one of their main advantages, the ability to absorb moisture, contributes to one of their main disadvantages: a majority of powders are entirely or largely composed of anhydrous elements, and in the course of absorbing moisture, can cause discomfort to the skin that is already very dry if used frequently.
Recent changes in powder technology have produced powders that contain substantial amounts of water(JP 58039609; JP 5065212). These products look and feel like standard powders before application, and are applied to the skin in the same way as standard powders. However, once they are rubbed or pressed onto the skin, they become liquid, thereby ensuring that the product remains in place, and also delivering moisture, rather than withdrawing it. These powder-to-liquid products rely largely on the presence of porous hydrophobic silica beads to hold the water that is released on application. These silica beads are themselves very gritty and dry, and ordinarily need to be used at a fairly high level to achieve the required water retention before application. Therefore, in order to compensate for the unpleasant feel of the silica, the formula usually contains a substantial amount of oil or other lubricants. Clearly, the presence of oil in the formula tends to counteract the desired effect of the oil absorption by the powder, thereby defeating at least one purpose of the product. Therefore, there continues to be a need for a powder composition that delivers moisture to the skin, yet achieves a smooth, non-gritty feel on the skin without the necessity of the addition of oil to the product or to the skin.
SUMMARY OF THE INVENTION
The invention provides a powder composition that is converted to liquid when applied to the skin. The compositions comprises hydrophobically-coated porous silica into which is incorporated an aqueous phase comprising water and a water-soluble polymer. In a preferred embodiment, the powder contains substantially no oil, and the aqueous phase contains one or more water-soluble actives. The powder compositions of the invention have the valuable property of being able to deliver a variety of water soluble actives in powder form, have a smooth, cooling feeling when applied to the skin, and avoiding some of the problems associated with other types of powders which may frequently contain oil.
DETAILED DESCRIPTION OF THE INVENTION
The compositions of the invention are prepared as loose powder compositions containing fairly high levels of water; upon application and rubbing of the powder on the skin, the composition releases water, and becomes liquid on the skin. Such a product is quite versatile, in that it provides the advantages of a powder, such as portability and ease of application, the feeling of dryness upon initial application on the skin in hot weather, and absorption of oils by the contained powders. However, it has the added advantage of containing a large quantity of water, which permits the delivery of valuable water soluble actives, and also provides a burst of cool moisture when rubbed into the skin.
Powder-to-liquid compositions are known in the art, as noted above, and many are based on the use of porous silica particles to hold the water phase of the composition. The more silica particles present, the more water the composition can hold. However, silica particles, when present in large quantities, confer a dry and gritty feeling on the skin. Thus, previous such compositions relied on the addition of oil to the composition to mask the unpleasant feeling of the silica as it is applied. Like the prior art products, the base for the powder compositions of the present invention are also water-absorbing porous spherical silica materials, preferably a fumed silica. However, as shown below, the nature of the water phase of the present compositions differs from those previously known in such a way as to allow reduction of the amount of silica to relatively low levels, while retaining the water-holding capacity, and permitting substantial elimination of added oil from the formula.
Preferably, the porous silica materials used in the compositions are hydrophobically coated. The hydrophobic coating may be any which is typically used for such purposes, e.g., a hydrocarbon or silicone coating, and preferably is one that is covalently bonded to the particle. In a preferred embodiment, the silica is coated with a silicone-based coating, such as an organosiloxane or polysiloxane or a silicone oil. The particle size is preferably about 0.01-40&mgr;, more preferably about 0.01-20&mgr;, and most preferably about 0.01-10&mgr;. Examples of suitable coated particles are trimethyl silylate-coated silica, dimethyl silylate coated silica, octyl silylate-coated silica, or silicone oil-coated silica. Preferred particles are trimethyl silylate-coated silica, commercially available from Cabot. The silica particles normally constitute from about 0.05 to about 10%, preferably about 0.1 to about 5%, more preferably about 0.25 to about 3%, and most preferably below 3%, by weight of the total composition.
In the powder form, occupying the pores of the silica particles is an aqueous phase, the basis of generating the liquid form of the composition. The aqueous phase may be any cosmetically acceptable water-based material, such as deionized water, or a floral water, or any water miscible liquids, such as alcohols. The water and/or water miscible liquids will normally constitute from about 50 to about 90%, preferably about 60 to about 80%, by weight of the total composition. The aqueous phase of the present composition is unique, in the presence of highly absorbent water-soluble polymers. The polymers employed can be any substantially surfactant-free, water-soluble polymer, such as homo- and copolymers of vinyl pyrrolidone, e.g., PVP, or PVP/PVA copolymer, homo-or copolymers of vinyl alcohol, such as polyvinyl alcohol, homo-or copolymers of acrylic and/or methacrylic acids, and salts and esters thereof, cellulosic polymers, polyethylene glycols and polyurethanes. Preferred are acrylate polymers and copolymers, particularly sodium polyacrylate. The water-soluble polymer is used in the water phase in an amount of from about 0.01 to about 5%, preferably about 0.1 to about 3%, most preferably about 0.1 to about 1%, by weight of the total composition. The use of the water-soluble, highly absorbent polymer, permits the retention of larger amounts of water within a smaller quantity of silica particles than would otherwise be possible, thereby reducing the unpleasant effect of the silica particles on the skin.
Another important aspect of the water phase is the ability to deliver water-soluble actives or skin-conditioning agents to the skin in an initial powder form. Any water-soluble active component can be added to the water
Lahanas Konstantinos M.
Miklean Saul
Santos Erlinda
Vrabie Nicolae
Color Access Inc.
Dodson Shelley A.
George Konata M.
Kenyon & Kenyon
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