Title:  Aqueous carrier systems for water-insoluble materials

United States Patent:  6,221,389

Assignee:  L'Oreal (Paris, FR)

Filed:  January 11, 2000

PCT NO:  PCT/US98/10617

102(e) Date:  January 11, 2000

PCT PUB. Date:  December 17, 1998

A composition containing at least one organic phospholipid capable of forming bilayers in aqueous solution;at least one amphoteric surfactant; and at least one nonionic surfactant present in an amount by weight equal to or greater than the amount of the phospholipid. The invention also relates to a delivery system for water-insoluble ingredients containing the above components, at least one water-insoluble ingredient, and an aqueous phase, wherein the organic phospholipid, amphoteric surfactant, and nonionic surfactant are present in a combined amount sufficient to allow the water-insoluble ingredient to be incorporated into the system. A method of treating keratinous susbstances is also disclosed.

BEST MODE FOR CARING OUT THE INVENTION

Advantageously, the present invention allows water-insoluble materials or ingredients to be solubilized in an aqueous solution. No alcohol is required for cosolubilization, and there is no need for liposome preparation. Further, when the water evaporates, the residue left behind includes the water-insoluble material and/or the phospholipid.

The composition of the invention is also easy to formulate and is gentle on the hair, skin, or eyelashes because the surfactants used are generally mild. Unlike the attempted solubilization of phospholipids in the prior art, the present invention requires the presence of at least one nonionic surfactant and at least one amphoteric surfactant in the concentrated solutions of phospholipid.

The compositions and delivery systems of the present invention readily deposit the organic phospholipid/water-insoluble substances on the hair, skin, and eyelashes, and, because of their inherent insolubility, resist being washed off with water. Accordingly, these compositions and delivery systems can be used in hair shampoos, conditioners, hair dyeing compositions, including oxidative dyes and bleaches, permanent waving compositions, curl relaxing compositions, hair setting compositions, bath and body products, sunscreens, or cosmetics such as mascaras and foundations.

These systems can also be used to deliver active water-insoluble pharmaceutical ingredients, particularly in topical applications. Such systems could further help protect against oxidation and rancidity by protecting sensitive ingredients in pharmaceuticals or foods.

Additionally, the "load" carried by these systems can be quite high, a benefit that inures both to the user and to the manufacturer in an economic sense. Load is defined as the weight of added hydrophobe (water-insoluble material) divided by the weight of the phospholipid expressed as a percentage. Thus, 1 g of hydrophobe in a composition with 5 g phospholipid is a 1/5 or 20% load. In the art, 50% is considered a high load and can be achieved with certain hydrophobes and surfactant combinations.

Without being bound to a particular theory, the inventors believe that in the composition of the present invention, an organized structure, likely a laminar gel, is formed between the organic phospholipid and the nonionic surfactant and is solubilized by the amphoteric surfactant. The organized structure can incorporate other water-insoluble materials or hydrophobes. In aqueous systems, the structure remains organized, as evidenced by the clarity of the solution, exhibiting a slight Tyndall light scattering effect, and, when concentrated, showing lamellar anisotropic structures under polarized light.

In one embodiment, therefore, the invention is drawn to a composition comprising at least one organic phospholipid capable of forming bilayers in aqueous solution, at least one amphoteric surfactant, and at least one nonionic surfactant, where the nonionic surfactant is present in an amount by weight equal to or greater than the amount of the phospholipid. Neither the amphoteric nor the nonionic surfactant alone will give a satisfactory solution with the organic phospholipids. When dissolved in either an amphoteric or a nonionic surfactant, solubility for the phospholipid was poor compared to solubility in the mixture of surfactants of the present invention.

With respect to the ingredients of the inventive composition, the preferred organic phospholipids capable of forming bilayers in aqueous solution are lecithins. Lecithins are mixtures of phospholipids, i.e., of diglycerides of fatty acids linked to an ester of phosphoric acid. Preferably, lecithins are diglycerides of stearic, palmitic, and oleic acids linked to the choline ester of phosphoric acid. Lecithin is usually defined either as pure phosphatidyl cholines or as crude mixtures of phospholipids which include phosphatidyl choline, phosphatidyl serine, phosphatidyl ethanolamine, phosphatidyl inositol, other phospholipids, and a variety of other compounds such as fatty acids, triglycerides, sterols, carbohydrates, and glycolipids.

The lecithin used in the present invention may be present in the form of a liquid, powder, or granules. Lecithins useful in the invention include, but are not limited to, soy lecithin and hydroxylated lecithin. For example, ALCOLEC S is a fluid soy lecithin, ALCOLEC F 100 is a powder soy lecithin, and ALCOLEC Z3 is a hydroxylated lecithin, all of which are available from the American Lecithin Company.

In the present invention, lecithin is preferably used in an amount greater than 0 to about 5% by weight of the composition as a whole. Since lecithin itself is not a pure raw material and may have free glycerides, glycerin, fatty acids, and soaps, adjustments in this ratio may need to be made, i.e., one source of lecithin may require different ratios of nonionic and amphoteric surfactants than another to achieve maximum clarity of solution. Preferably, the composition of the invention forms a clear solution, though the purpose of the invention is achieved just as effectively with a slightly cloudy solution.

Other than lecithins, another group of phospholipids which may be useful in the present invention are multifunctional biomimetic phospholipids. For example, the following multifunctional biomimetic phospholipids manufactured by Mona Industries may be useful: PHOSPHOLIPID PTC, PHOSPHOLIPID CDM, PHOSPHOLIPID SV, PHOSPHOLIPID GLA, and PHOSPHOLIPID EFA.

The amphoteric surfactants useful in the present invention include, but are not limited to, betaines, sultaines, hydroxysultaines, alkyl amphodiacetates, alkyl amphodipropionates, and imidazolines, or salts thereof. It is recognized that other fatty acid condensates such as those formed with amino acids, proteins, and the like are suitable. Amphoteric surfactants are typically available for commercial sale in solution form with the active surfactant accounting for approximately 40% of the total solution weight. Cocoamphodipropionate is particularly preferred, for example, MIRANOL C2M-SF Conc. (disodium cocoamphodipropionate), in its salt-free form, available from Rhone-Poulenc. MIRANOL is sold in solution form with amphoteric surfactants composing approximately 40% of the total solution weight; for example, 10 g of MIRANOL contain about 4 g of amphoteric surfactant. Also preferred is CROSULTAINE C-50 (cocamidopropyl hydroxysultaine), available from Croda. CROSULTAINE is also sold in solution form with the amphoteric surfactant composing approximately 50% of the total solution weight. The amphoteric surfactants are preferably present in the composition in an amount ranging from about 2 to 25% by weight of the composition as a whole when 5% of the organic phospholipid, preferably lecithin, is used. When the phospholipid/amphoteric/nonionic system is employed as a carrier for a water-insoluble polymer or resin, the amphoteric surfactants are preferably present in the composition in an amount ranging from about 6 to 25% by weight. When the phospholipid/amphoteric/nonionic system is employed as a carrier for a lipophilic material, the the amphoteric surfactants are preferably present in the composition in an amount ranging from about 4 to 20% by weight. Other amphoteric surfactants useful in the present invention include disodium wheatgermimido PEG-2 sulfosuccinate, available under the trade name MACKANATE WGD from McIntyre Group Ltd., which is a solution with amphoteric surfactants composing approximately 39% of the total solution weight, and disodium soyamphodiacetate, available under the trade name MACKAM 2S from McIntyre Group Ltd., which is a solution with amphoteric surfactants composing approximately 34.5% of the total solution weight.

The nonionic surfactants useful in the present invention are preferably formed from a fatty alcohol, a fatty acid, or a glyceride with a C₈ to C₂₄ carbon chain, preferably a C₁₂ to C₁₈ carbon chain, more preferably a C₁₆ to C₁₈ carbon chain, derivatized to yield a Hydrophilic-Lipophilic Balance (HLB) of at least 10. HLB is understood to mean the balance between the size and strength of the hydrophilic group and the size and strength of the lipophilic group of the surfactant. Such derivatives can be polymers such as ethoxylates, propoxylates, polyglucosides, polyglycerins, polylactates, polyglycolates, polysorbates, and others that would be apparent to one of ordinary skill in the art. Such derivatives may also be mixed polymers of the above, such as ethoxylate/propoxylate species, where the total HLB is preferably greater than or equal to 10. Preferably the nonionic surfactants contain ethoxylate in a molar content of from 10-25, more preferably from 10-20 moles.

Nonionic surfactants may be selected from, but are not limited to, the following:

    # of Cs Name        Trade Name
    C-12    Laureth-23  BRIJ 35, available from ICI Surfactants
    C-16    Ceteth-10   BRIJ 56, available from ICI Surfactants
    C-16    Ceteth-20   BRIJ 58, available from ICI Surfactants
    C-16    IsoCeteth-20 Arlasolve 200, available from ICI Surfactants
    C-18    Steareth-10 Volpo S-10, available from Croda Chemicals Ltd.
    C-18    Steareth-16 Solulan-16, available from Amerchol Corp.
    C-18    Steareth-20 BRIJ 78, available from ICI Surfactants
    C-18    Steareth-25 Solulan-25, available from Amerchol Corp.
    C-18.dbd. Oleth-10    BRIJ 97, available from ICI Surfactants
    C-18.dbd. Oleth-20    Volpo-20, available from Croda Chemicals Ltd.

Alkyl polyglucose surfactants sold under the name PLANTAREN, available from Henkel, may also be used. The nonionic surfactant is preferably present in an amount of about 5 to 20% by weight relative to the weight of the whole composition when 5% lecithin is used. More preferably, the nonionic surfactant is present in an amount of about 10 to 20% by weight.

In one preferred embodiment of the composition of the present invention, the organic phospholipid capable of forming bilayers in aqueous solution, the amphoteric surfactant, and the nonionic surfactant are present in the composition such that the nonionic surfactant and the amphoteric surfactant are each present in an amount by weight greater than the amount of phospholipid. In a more preferred embodiment, the amount of phospholipid in the composition is kept fixed while the amounts of the amphoteric and nonionic surfactants are increased. In a still more preferred embodiment, calculating the phospholipid as present at a value of 1, the phospholipid, amphoteric surfactant and nonionic surfactant are preferably present in the composition in a ratio ranging from about 1:0.8:2 and above by weight relative to the whole composition, i.e., where the amounts of the surfactants can be increased independently of each other but the amount of phospholipid stays fixed. The ratio is considered to be "above" 1:0.8:2 when the amount of either of the surfactants increases. When the phospholipid/amphoteric/nonionic system is employed as a carrier for a lipophilic material, the ratio preferably ranges from about 1:1.2:2 and above. When the phospholipid/amphoteric/nonionic system is employed as a carrier for a water-insoluble polymer or resin, the ratio is preferably about 1:1.2:3 and above, and more preferably above about 1:1.2:4. The loading capability for hydrophobes carried by the delivery system of the present invention is maximized if the ratio of nonionic surfactant to phospholipid is minimized, with the bilayers still being solubilized, because an excess of nonionic surfactant may disrupt the organized structure.

In one preferred embodiment, the composition of the present invention comprises ALCOLEC S (soy lecithin), MIRANOL C2M-SF Conc. (disodium cocoamphodipropionate, an amphoteric surfactant), ARLASOLVE 200 (IsoCeteth-20, a nonionic surfactant) in a ratio of 5:15:10 (which is a LAN ratio of 1:1.2:2) when a lipophilic water-insoluble ingredient is employed, and 5:15:20 (which is a LAN ratio of 1:1.2:4) when a water-insoluble polymer, resin, or latex is employed, wherein the ratios are calculated by weight relative to the whole composition. In general, the preferred compositions of the invention are known as the "LAN" because they contain a lecithin (L), an amphoteric surfactant (A), and a nonionic surfactant (N). Although lecithin is particularly preferred, the amphoteric and nonionic surfactants may vary.

When used as an ingredient in further formulations, the LAN is compatible and generally gives clear solutions with anionic surfactants such as alkyl sulfates and ethoxylated alkyl sulfates. Other anionic surfactants such as sulfosuccinates may also be used. Typically, LAN compositions can resist storage at 45^oC. for three months or more, which would predict that they have a shelf life at room temperature of at least three years.

In another aspect, the present invention relates to an aqueous delivery or carrier system comprising: at least one organic phospholipid capable of forming bilayers in aqueous solution, at least one nonionic surfactant preferably present in an amount greater than or equal to the amount of the phospholipid, at least one amphoteric surfactant, at least one water-insoluble ingredient, and an aqueous phase. The lecithin, nonionic surfactant, and amphoteric surfactant are present in a combined amount sufficient to allow the at least one water-insoluble ingredient to be incorporated into or solubilized by the aqueous system. The amount sufficient for solubilization may vary depending on the type of composition; for example, shampoo and mascara formulations require a lower concentration of LAN than do conditioner, deep treatment, bleach, permanent wave, dye, and relaxant compositions.

Water-insoluble materials or ingredients include, but are not limited to the following:

(1) Lipophilic "ingredients" or "materials" such as silicones, oil-soluble vitamins such as Vitamin E and Vitamin A, sunscreens, ceramides and natural oils: The lipophilic ingredients may be in the form of sunscreens, bacteriostats, moisturizers, colors, topical pharmaceuticals and the like. Preferred lipophilic ingredients include: Vitamin E, Vitamin E Acetate, Vitamin A Palmitate, olive oil, mineral oil, 2-oleamido-1,3-octadecanediol, octylmethoxy cinnamate, octyl salicylate, and silicones such as dimethicone, cyclomethicone, phenyl trimethicone, dimethiconol, dimethicone copolyol, and laurylmethicone copolyol. The lipophilic ingredients will, for example, moisturize or condition the skin, hair, and/or eyelashes and leave behind no oily feel.

(2) Water-insoluble polymers, resins, and latexes which are unneutralized or partially neutralized, wherein the polymers and resins include but are not limited to those containing carboxyl moieties, such as acrylates and other carboxy polymers. Typically, water-insoluble polymers and resins have to be neutralized to about 90% of their carboxyl moieties to make them water soluble for the purpose of formulating products in aqueous solution and for the purpose of making products which have good non-build-up properties, i.e., can be easily washed off the hair after use. However, when used with the compositions of the present invention, little or no neutralization is needed to dissolve these polymers/resins. In part, an unneutralized or partially neutralized water-insoluble polymer or resin is solubilized because it is neutralized by the amphoteric surfactant contained in the presently claimed delivery system, but the amphoteric surfactant acting alone will not solubilize the polymer or resin in water and allow the pH to be acidic. As discussed with reference to the Gerstein patent above, if the polymer or resin is neutralized by the amphoteric surfactant alone, when one attempts to acidify the solution to prepare a hair care composition with acidic pH, as is desirable, the carboxyl moieties of the polymer or resin becomes unneutralized and precipitation occurs. It is the combination of the organic phospholipid, the nonionic surfactant, and the amphoteric surfactant of the present invention which achieves the solubility of the water-insoluble polymers or resins.

As for latexes, they generally have been used in cosmetics in an unneutralized form since they are used for their milky (insoluble) appearance. In the context of the present invention, however, water-insoluble latexes are neutralized to an alkaline pH and dissolve, producing a clear solution. To the best of the inventors' knowledge, neutralized latexes have not previously been used in cosmetic compositions.

In the case of the non-neutralized or partially-neutralized polymers or resins, where such substances are applied to the hair or skin from an alcoholic or aqueous/alcoholic system, their washability from the hair leaves a great deal to be desired. In contrast, where such polymers or resins are applied in a delivery system comprising at least one organic phospholipid; at least one amphoteric surfactant; and at least one nonionic surfactant, wherein the nonionic surfactant is present in an amount equal to or greater than the amount of the organic phospholipid, the polymers or resins can easily be rinsed off from the hair (no build-up) while providing strong hold for curls, if curls are what is desired.

The following are examples of polymers that can be incorporated into the delivery system of the present invention. The list is not intended to be limiting:

AMPHOMER LV-71 from National Starch (octylacrylamide/acrylates/butylaminoethyl methacrylate copolymer),

OMNIREZ-2000 from ISP (PVM/MA half ethyl ester copolymer),

RESYN 28-2930 from National Starch (Vinyl acetate/crotonates/vinyl neodecanoate copolymer),

LUVIMER 100P from BASF (t-butyl acrylate/ethyl acrylate/methacrylic acid), and

ULTRAHOLD STRONG from BASF (acrylic acid/ethyl acrylatelt-butyl acrylamide).

Unneutralized or partially neutralized water-insoluble latexes have been used as film-formers in various applications. The following are latexes that can be incorporated into the delivery system of the present invention:

AMERHOLD DR-25 from Amerchol (acrylic acidimethacrylic acid/acrylates/meth acrylates),

LUVIMER 36D from BASF (ethyl acrylatelt-butyl acrylatelmethacrylic acid), and

ACUDYNE 258 from Rohm & Haas (acrylic acid/methacrylic acid/acrylates/methacrylates/hydroxy ester acrylates).

Up to 60% by weight of each of these polymers/resins/latexes were dissolved in 35% phospholipid/amphoteric surfactant/nonionic surfactant solutions where the phospholipid was lecithin and the ratio of lecithin:amphoteric:nonionic was 1:1.2:4. All the solutions were clear, indefinitely dilutable with water without precipitation and stable after 2 months on the shelf.

The aqueous phase of the inventive delivery system can contain additional ingredients such as anionic surfactants, organic salts, inorganic salts, proteins, hair dyes, water-soluble polymers, quatematy ammonium compounds, complex and simple carbohydrates, amino acids, preservatives and fragrances.

If the inventive system is to be used in concentrated form, i.e., with about 5% by weight of the organic phospholipid and 1% of added water-insoluble ingredient, the composition preferably has a pH ranging from 4-12 for maximum stability and clarity. The more concentrated the solution, the better the delivery.

If this blend is diluted with water or the blend is used as an ingredient in another composition, then the pH has a broader range, i.e., preferably ranges from 2-12, and a wider variety of additives can be included in the solution. When water is added to a concentrated LAN, it may appear to form a cloudy solution at first if a large amount of water is added at once. The LAN will eventually go into solution, however, and become clear or at least clearer. The time to clear decreases as the LAN ratio increases. Once the organized structure of the LAN forms, the addition of more water does not affect clarity. These dilute blends are still very effective in delivering water-insoluble ingredients. The blends can be freeze-dried to hygroscopic solids that redissolve into water. Encapsulation of such solids so that they do not pick up and retain excess moisture is also contemplated. Such encapsulated solids can have desirable storage properties and would be easy to dissolve into water at various dilutions. Understandably, the need for dilution varies depending on the water-insoluble material to be employed.

Another embodiment of the present invention is drawn to a process for preparing the aqueous system of the present invention. This process comprises: (a) combining the following ingredients to obtain a mixture: at least one organic phospholipid capable of forming bilayers in aqueous solution, at least one nonionic surfactant, and at least one amphoteric surfactant, where the nonionic surfactant is present in an amount by weight equal to or greater than the amount of the organic phospholipid, (b) heating the mixture obtained in step (a), and (c) adding an aqueous solution to the heated mixture to obtain the desired carrier system. Water-insoluble ingredients may be added in step (a). Preferably the carrier system obtained can cany a high load (i.e., 50% is considered a high load) of the organic phospholipid/water-insoluble ingredient. The mixture is preferably heated at a temperature of 65^oC. to 85^oC., depending on the melting points of the solid surfactants.

More specifically, the preparation of the carrier system of the present invention may be carried out as follows. Lecithin (L) is dispersed in water. The water-insoluble material is combined with nonionic surfactant(s) (N) at appropriate ratios and added to the lecithin/water dispersion. An amnphoteric surfactant (A) is added and the mixture is heated, preferably to a temperature of from 75^oC. to 85^oC. The combination of these ingredients results in a solution which is clear to slightly hazy and is referred to as the "LAN," which can then be used as a "raw material" to make finished products.

Alternatively, lecithin, amphoteric surfactant(s) and nonionic surfactant(s) can be weighed to appropriate ratios and heated to 70^oC. with stirring. Water is then added q.s. at the same temperature. Another alternative method of preparation comprises adding the water-insoluble ingredient with mixing after solutions have cooled. This last alternative method helps protect heat-sensitive water-insoluble ingredients.

The resulting compositions may vary from clear to slightly hazy and are infinitely dilutable with water. The slight haze can be overcome by adjusting the ratio of lecithin to the surfactants, adjusting pH, or reducing concentrations of water-insoluble ingredients.

In another embodiment, the present invention is drawn to a method for treating keratinous substances such as, but not limited to, hair, skin, or eyelashes. First an aqueous solution is prepared containing at least one organic phospholipid capable of forming bilayers in aqueous solution; at least one amphoteric surfactant; at least one nonionic surfactant present in an amount by weight equal to or greater than the amount of the phospholipid; and at least one water-insoluble ingredient. The phospholipid, amphoteric surfactant, and nonionic surfactant are present in a combined amount sufficient to allow the water-insoluble ingredient to be incorporated into the aqueous solution. The aqueous solution is then applied to the keratinous substances. The term treating in the context of this invention includes, but is not limited to, shampooing, conditioning, dyeing, bleaching, permanent waving, relaxing, setting, moisturizing, and making-up, for example, applying mascara or foundation.

As mentioned previously, the composition and carrier system of the present invention can be used as an ingredient itself in, for example, shampoos, conditioners (rinse-off and leave-in), deep treatments for hair, body washes, bath gels, hair dyeing compositions, permanent wave formulations, relaxers, make-up preparations, particularly mascara and foundation, and skin creams or lotions.

With respect to hair products, the carrier system of the present invention can be used to formulate hair products, e.g., for normal hair, color-treated hair, dry hair, fine hair, and damaged hair. For each type of hair, the LAN can be used to create a regimen comprising shampoo, conditioner, and deep treatment, (i.e., deep conditioner). LAN compositions used for these products preferably contain lecithin (L), at least one amphoteric surfactant (A), such as disodium cocoamphodipropionate, and at least one nonionic surfactant (N), e.g., a blend of Oleth-10 and PPG-5-Ceteth-20. Additional nonionic, amphoteric, and also anionic surfactants can be added. The LAN compositions may further contain at least one water-insoluble ingredient (also referred to as a bydrophobe) such as olive, mineral, or other oils, octyl salicylate, Vitamin E (Tocopherol), octyl methoxycinnamate, and ceramides including 2-oleamido-1,3-octadecanediol.

In general, the concentration of the LAN is increased within each regimen from shampoo to conditioner to deep treatment. Thus, the deep treatment formulations have the most concentrated hydrophobe-carrying LAN.

The LAN systems of the invention can be further associated, in the hair products described above, with proteins including hydrolyzed soy protein, lauryldimonium hydrolyzed soy protein (cationic Soya protein) and wheat amino acids. The proteins could also include corn, wheat, milk, or silk proteins, collagens, keratins, or others. Furthermore, taurine and arginine hydrochloride may be associated therein to maximize protein binding to the hair. Cationic proteins or proteins in general may be stabilizers for the LAN and enhance its delivery by changing the charge on the surface of the LAN structure. The skin and the hair attract cationic ingredients, and proteins are generally substantive to these tissues.

In conditioning emulsions, nonionic emulsifiers such as glyceryl stearate and PEG-100 stearate can be used, and the LAN is treated as a water-insoluble, particularly a lipophilic, ingredient itself.

Other ingredients in the LAN hair care compositions may include cationic polymers, such as polyquaternium 4, polyquaternium 6, polyquaternium 7, polyquaternium 10, polyquaternium 11, polyquatemium 16, polyquaternium 22, and polyquaternium 32, cationic conditioners, such as quaternium 27, behenamidopropyl PG-dimonium chloride, hydroxyethyl tallowdimonium chloride, hexadimethrine chloride, stearalkonium chloride, and cetrimonium chloride, isoparaffms, sodium chloride, propylene glycol, preservatives such as phenoxyethanol, methylparaben, ethylparaben, and propylparaben, pH adjusters such as phosphoric acid, humectants such as trehalose, and emollients such as octyldodecanol. Many other examples of materials from the classes listed above would be readily known to one of ordinary skill in the art.

Further, shampoos, conditioners, and deep treatments within the scope of the present invention may be used on hair which has been treated, e.g., with color (dye or bleach) or chemicals (permanent wave or straightening), or which is dry or fine and show significant substantivity for the hair.

Claim 1 of 60 Claims

What is claimed is:

1. A composition comprising:

at least one organic phospholipid capable of forming bilayers in aqueous solution;

at least one amphoteric surfactant; and

at least one nonionic surfactant present in an amount by weight equal to or greater than the amount of said at least one phospholipid.

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