Rinsable skin conditioning compositions

Details Rinsable skin conditioning compositions Rinsable skin conditioning compositions

2002-11-18

2004-03-02

Dodson, Shelly A. (Department: 1616)

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Cosmetic, antiperspirant, dentifrice

C424S059000, C424S078020, C424S078080, C424S400000, C514S937000, C514S938000

Reexamination Certificate

active

06699488

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to rinsable, skin conditioning compositions. More particularly it relates to skin conditioning compositions comprising high internal phase emulsions substantially free of surfactant.
BACKGROUND OF THE INVENTION
Skin conditioning compositions that provide moisturizing benefits are known. Many of these compositions are aqueous systems comprising an emulsified conditioning oil or other similar material stabilized with surfactant. Typically, skin moisturizing compositions are in the form of lotions meant to be applied to the skin after bathing and throughout the day if reapplication is necessary.
Skin is made up of several layers of cells, which coat and protect the keratin and collagen fibrous proteins that form the skeleton of its structure. The outermost of these layers, referred to as the stratum corneum, is known to be composed of 25 nm protein bundles surrounded by 8 nm thick layers. Anionic surfactants and organic solvents typically penetrate the stratum corneum membrane and, by delipidization (i.e. removal of the lipids from the stratum corneum), destroy its integrity. This destruction of the skin surface topography leads to a rough feel and may eventually permit the surfactant or solvent to interact with the keratin, creating irritation.
It is now recognized that maintaining the proper water gradient across the stratum corneum is important to its functionality. Most of this water, which is sometimes considered to be the stratum corneum's plasticizer, comes from inside the body. If the humidity is too low, such as in a cold climate, insufficient water remains in the outer layers of the stratum corneum to properly plasticize the tissue, and the skin begins to scale and becomes itchy. Skin permeability is also decreased somewhat when there is inadequate water across the stratum corneum. On the other hand, exposure to high water concentration for long periods of time on the outside of the skin causes the stratum corneum to ultimately sorb three to five times its own weight of bound water. This swells and puckers the skin and results in approximately a two to three fold increase in the permeability of the skin to water and moisturizer molecules. In the shower or bath, as skin becomes hydrated, this is recognized as an ideal time to deliver moisturizer to the skin since absorption of the moisturizer will be high.
It is further desirable to deliver the above skin conditioning benefits via an in-the-shower or in-the-bath lotion. Unfortunately, in the shower/bath, moisturizers are often readily rinsed from the skin. This is particularly true when surfactant is present.
Thus, a need exists for compositions, which will effectively deposit moisturizers and/or other skin benefit agents in the shower and/or bath and thereby assist the stratum corneum in maintaining its barrier and water-retention functions at optimum performance in spite of deleterious interactions which the skin may encounter in washing, work, and recreation.
Desirable properties of such skin care compositions are to provide good skin feel, water retention, moisturization, absorption, and rub-in characteristics. One way of delivering high moisturization to the skin is to incorporate polyhydric alcohol-like humectant materials such as glycerine into a composition. Skin compositions with high levels of polyhydric alcohols and therefore high levels of moisturization when left-on the skin, however, are readily rinsed away in the shower and/or bath by the consumer. An alternative way of delivering desirable benefits to the skin is to incorporate oil-soluble skin care ingredients such as petrolatum into skin care compositions. Compositions, which incorporate the oil as an oil-in-water emulsion, must stabilize the emulsion which is generally done with surfactant (typically nonionic surfactant for lotions and anionic or amphoteric surfactant for lathering products). Again, such compositions when stabilized with surfactant, deposit poorly on the skin due to emulsification of the oil by the surfactant.
Another method previously used to deposit oil more effectively is to deliver the oil via a water-in-oil emulsion. Such compositions however, have big trade-offs in terms of poor (greasy) aesthetics, poor spreading on skin and creation of unsafe, slippery shower and/or tub floors.
It is a tremendous challenge to deposit effective amounts of skin conditioning ingredients on skin via a rinsable skin conditioning composition that also has excellent consumer acceptance. While not wishing to be bound by theory, it is believed that the oil soluble conditioning agents are easily emulsified by the surfactant present in most body wash and body lotion compositions. Therefore, the conditioning agents are rinsed away during the personal cleansing process. Although attempts have been made to formulate two-in-on body wash products that not only cleanse the skin, but additionally deliver skin moisturization, they don't generally deposit sufficient amount of skin conditioning ingredients to deliver the same level of skin moisturization as a leave-on lotion. This inadequate conditioning leaves consumers with an unmet need.
Accordingly, the need remains for a rinsable, skin-conditioning composition that can provide improved conditioning and other skin care benefits to human skin. Additionally, there remains a need for a rinsable, skin-conditioning composition which exhibits pleasing tactile properties and increased deposition of skin conditioning and/or skin care agents. The need also remains for in-shower and/or bath lotion compositions which show low levels of stickiness or tackiness whilst providing high levels of moisturization, as well as providing excellent skin feel, skin softness and skin smoothness benefits.
It has now been unexpectedly found that compositions comprising high internal phase oil-in-water emulsions show excellent oil deposition, excellent moisturization benefits, with low levels of stickiness or tack and superior product stability. These compositions can be formulated at surprisingly high viscosities while maintaining excellent spreadability on wet skin. The compositions also show good skin feel, skin softness and skin smoothness benefits. Other benefits in using high internal phase emulsions are that they are very easy to manufacture, they give the formulated great control over oil droplet size, they are low irritating and they allow for emulsification of previously incompatible materials in the same product. These and other benefits will be discussed in greater detail below.
The present invention provides rinsable, skin-conditioning compositions, which may further comprise skin benefit agents. These compositions provide improved aesthetics and skin feel during and/or after application, and are especially useful in providing improved deposition or effectiveness of skin conditioning agents to the desired area of the skin. The benefits of the compositions of the present invention are further improved
The present invention further provides a method of conditioning the skin using the described compositions.
SUMMARY OF THE INVENTION
The present invention meets the aforementioned needs by providing a rinsable skin conditioning composition comprising a an oil-in-water emulsion wherein the composition has a Deposition Efficiency (DE) of at least about 2% wherein DE=[W
after
−W
0
]/[W
before
−W
0
]×100. The present invention further relates to a rinsable skin conditioning composition comprising (a) at least one high internal phase emulsion comprising (i) an oil; (ii) a stabilizer; (iii) water; and (b) the balance being conventional cosmetic and skin care ingredients.
The present invention further relates to a rinsable skin conditioning composition wherein the composition comprises (i) from about 20% to about 90% by weight of the oil; (ii) from about 0.1% to about 10% by weight of the stabilizer; (iii) from about 9.5% to about 79.5% by weight of water; and (iv) from about 0% to about 2% by weight of a perfume
The present inven

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