Emulsifier-free finely dispersed systems of the oil-in-water or water-in-oil type

Fine dispersion systems without emulsifiers oil-in-water type and water-in-oil type.

The present invention relates to the systems in fine dispersion, without emulsifiers, of the oil-in-water and water type in oil, preferably used in dermatological preparations or cosmetics

Emulsions are generally understood as those heterogeneous systems, which are composed of two non-miscible liquids each other or only in part, which are generally called phases. In an emulsion, one of the two liquids is dispersed in the form of fine drops in the other liquid.

If the two liquids were water and oil and had oil droplets finely distributed in the water, it would be an oil-in-water emulsion (O / W emulsion) eg the milk). The fundamental character of an O / W emulsion is marked For the water. In a water-in-oil emulsion (W / O emulsion, eg the butter) is the inverse principle, where the character Basic in this case is determined by the oil.

To achieve a lasting dispersion of a liquid in another, it will be necessary in the case of emulsions in the current sense of the word, the addition of an active substance in the interface (emulsifier) ​​The emulsifiers have a amphiphilic molecular structure, composed of a polar fraction (hydrophilic) and a non-polar (lipophilic), separated spatially with each other. In simple emulsions, they are taken in a phase finely dispersed droplets coated with a capsule of emulsifier, while in the second phase you have droplets of water in water / oil emulsions or vesicle emulsions of lipid in oil / water. Emulsifiers serve to reduce the boundary surface tension between the phases, hence they are available on the surfaces interface between both liquids. These form in the interfaces, oil / water boundary surface films, with which counteracts the irreversible flow of the droplets. For stabilize emulsions, mixtures of emulsifying products.

Conventional emulsifiers can be classified according to their hydrophilic molecular fraction in ionic (anionic, cationic and amphoteric) and non-ionic:

<dl><dt>?</dt><dd>The best known example of a Anionic emulsifier is soap, which is usually referred to as water soluble sodium or potassium salts of fatty acids higher saturated and unsaturated.</dd></dl>

<dl><dt>?</dt><dd>The most representatives important of cationic emulsifiers are the compounds Ammonia quaternaries.</dd></dl>

<dl><dt>?</dt><dd>The hydrophilic molecular fraction of non-ionic emulsifiers, it is often composed of glycerin, polyglycerin, sorbitan, carbohydrates and polyoxyethylene glycols that are frequently intertwined with the lipophilic molecular fraction, by ester and ether bonds. These are generally composed of fatty alcohols, fatty acids or iso fatty acids.</dd></dl>

By varying the structure and the size of polar and non-polar molecular fraction, it is possible modify up to broad limits, lipophilicity and hydrophilicity of emulsifiers

The correct selection of emulsifiers is decisive for the stability of an emulsion. It is also necessary take into account the characteristics of all substances contained in the system. Considering, eg emulsions for the skin care, polar oil components and pe Ultraviolet (UV) filters create instabilities. Apart from the emulsifiers are still used other stabilizers, which pe they act by increasing the viscosity of the emulsion and / or by way of protective colloids.

Emulsions represent an important type of product in the sector of cosmetic preparations and / or dermatological

Cosmetic preparations are used Basically for skin care. Skin care in the cosmetic sense, means in the first line reinforce and restore the natural function of the skin as a barrier against influences environmental (eg dirt, chemicals, microorganisms) and against the loss of substances of the body (eg water, natural fats, electrolytes). Yes this function is damaged, excessive may occur resorption of toxic or allergenic substances or, to the attack of microorganisms and consequently to toxic skin reactions or allergic

The object of skin care also consists of in compensating the skin for the loss of fat and water caused by the daily washes This is especially important, when the Natural regeneration capacity is not enough. On the other hand, Skin care products should protect against environmental influences especially against the sun and the wind and delay its aging.

Cosmetic preparations are also used as deodorants These formulations serve to remove the smell body that occurs when fresh odorless sweat is replaced by microorganisms.

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Topical medical formulations contain general rule one or several medications in active concentration. To simplify, the clear difference between the cosmetic application and the respective products, to legal provisions of the German Federal Republic (eg Cosmetic Order and the Law of Food Products and Medicines).

In fact, the use of the usual emulsifiers It does not present any inconvenience in cosmetic preparations or dermatological However, emulsifiers can, as it happens with any chemical substance, cause reactions derived in isolated cases when there is an over-sensitivity or allergy by the user.

Thus it is known for example that, determined Light dermatosis caused by specific emulsifiers, it they also trigger, due to various fats and simultaneous exposure to sunlight. Such dermatoses caused by light are called also "acne from Mallorca". As for these have not spared tests, to reduce to a minimum the amount of emulsifiers currents and even at best, fully.

A reduction in the amount of emulsifiers necessary may take place, for example, when once used the finely distributed solid particles, present additionally a stabilizing effect. This produces a enrichment of solid matter at the oil / water interface in shape of a layer, which prevents the joint confluence of the scattered phases. Of special importance they are likewise, no longer the chemical characteristics but the superficial ones of the Solid particles.

Pickering obtained in 1910 for the first time paraffin-water emulsions that only stabilized by adding various solid substances such as basic copper sulfate, basic iron sulfate or others metal sulfates These types of emulsions are also called for this reason, Pickering emulsions.

So to speak, the original forms of Pickering emulsions succumbed immediately as effects undesirable side effects, in different technical processes, such as for secondary oil extraction, the extraction of bitumens from tar sand and other procedures of separation, in which two non-miscible liquids intervened between yes and finely dispersed solid particles. In general here it it treats water / oil emulsions W / O that are stabilized by mineral solids For this reason, the investigation of respective systems has immediately reached the maximum point interest in research activities such as systems oil-water-black smoke or oil-water-slate powder.

Primary investigations have also demonstrated that, a characteristic for a Pickering emulsion is that solid particles are arranged at the interface between the two liquid phases and there, so to speak, form a barrier mechanical against contamination of liquid droplets.

A relatively new technical development, part of the use of Pickering emulsions as a basis for cosmetic or dermatological preparations.

A possibility of stabilization of solids in the case of a Pickering emulsion for a preparation cosmetic or dermatological, it consists according May-Alert (The Pharmacy of Our Time, 15. 1986, No. 1, 1-7) for example in using mixtures of emulsifiers, which contain both anionic surfactants and also cationic. Since by adding anionic surfactants and cationics always result in insoluble combinations, and electronically neutral, by controlled precipitation of these neutral surfactants in the oil / water interface are achieved additional stabilization of solids.

In this regard, the European publication O 686 391 describes emulsions of the water-in-oil type, exempt from active substances, superficially and that only stabilize by solid substances. For stabilization they are used in this case, spherical particles of polyalkylsilsquioxane, of a diameter from 100 nm to 20 µm. These emulsions can be called as previously stated as Pickering emulsions.

Pickering emulsions are stabilized by the use of solid substances or appropriate pigments. In In any case, these preparations are at the level of technique and in general they have the disadvantage of being limited to a narrow field of application or to a selection of substances to use limited, which can only be formulated with some stability, of this way. For some specialties of cosmetics (eg for the field of skin care) Pickering emulsions present technique level a few cosmetic features satisfactory.

The objective, then, is to solve the inconveniences at the technical level. Offering specifically cosmetic and dermatological bases for formulations of this nature that are characterized by their compatibility with the skin.

On the other hand, it is also the mission of the present invention, offer products with a variety of application the most wide possible. Thus, for example, the basis for formulations in the form of emulsions for cleaning, preparations for body and skin care, or deodorants, but also different forms of presentation pharmaceutical-medical, for example formulations against acne and other skin problems.

It turned out surprising and never seen in mode some by the specialist that, Pickering emulsions that have finely dispersed water-in-oil systems or oil in water, contain

(1) an oil phase,

(2) a water phase,

(3) at least one type of microfine particle, what

<dl><dt>to)</dt><dd>show a particle size minimum average of 200 nm,</dd></dl>

<dl><dt>b)</dt><dd>present both characteristics hydrophilic as well as lipophilic, which also had a character amphiphilic and that were dispersible both in water and also in oil and that,</dd></dl>

<dl><dt>c)</dt><dd>in case specific surface coatings.</dd></dl>

(4) at least one electrolyte and

(5) at most 0.5% by weight of one or more emulsifiers

and that they could remedy the inconveniences at the level of the technique.

According to the invention, it is especially advantageous. that, the formulations clearly contain less than 0.5% by weight of one or more emulsifiers, or possibly even Prepare completely free of emulsifiers.

The formulations according to the invention are all the aspects, prepared completely satisfactory, that in front of conventional Pickering emulsions have stability clearly superior, hence they are especially appropriate, as a basis for the forms of preparation that will serve to Multiple fields of application. In the sense of the present invention, especially water / oil pickering emulsions, they are surprisingly and extraordinarily stable.

In addition the formulations referred to in invention are distinguished by extraordinary compatibility with the skin. On the other hand, it was surprising that, these formulations to which the invention relates, which are presented in the form of sunscreen agent, show superior efficacy in comparison with the usual sunscreen formulations.

While preparations at the level of the technique already with a pigment content of 1% by weight, produce a coarse sensation, after application on the skin, that in higher concentrations of pigments still increases, the formulations referred to in the invention do not leave surprisingly no sensation of dryness or coarseness about the skin, but exhibit much more cosmetic characteristics attractive.

It is true that at the level of the technique apart from Pickering emulsions free of emulsifiers are presented finely dispersed dermatological or cosmetic formulations, which in general they are designated as hydrodispersions and they are dispersions based on a liquid, a semi-solid lipid phase or solid inside (discontinuously) in an outer phase aqueous (continuous). In any case, the level of technique does not could indicate the path to the present invention.

In hydrodispersions a liquid lipid phase in an external aqueous phase it can guarantee the stability of so that a gel structure is formed in the aqueous phase in which lipid droplets can be stably suspended.

German publication 44 25 268 describes Dermatological or cosmetic formulations free of emulsifiers, stable and finally dispersed oil-in-water type, which apart one phase oil and one water, contain one several thickeners from the group of polymers of acrylic acid, polysaccharides and their alkyl ethers, where for this thickener should not be able to determine no reduction in its surface tension limit.

Based on similar hydrodispersions they have disclosed in the German publication document 43 03 983, sunscreen, dermatological or cosmetic formulations which essentially lack emulsifiers, where in the phase hydrodispersion lipid micropigments have been added inorganic, which serve as filtering substances for ultraviolet (UV).

In the document EP-A-847 750 are published effective combinations such as sunscreens, which contain inorganic pigments and that, can be hydrophilized, UV filters, which in their molecular structure contain sulfuric acid groups or sulfonates and that are basically free of emulsifiers

Pickering emulsions, oil / water in the sense of the present invention on the contrary can be obtained, for which, according to the invention for the elaboration of these Pickering oil / water emulsions will disperse particles suitable amphiphiles, first <i>in the aqueous phase</i> and the aqueous phase then joins the fatty phase. According to him invention, water / oil pickering emulsions are on the contrary obtainable by dispersion <i>in the fatty phase</i> of particles amphiphiles suitable according to the invention, for the preparation of Water / oil pickering emulsions.

According to the invention, the electrolyte (s) it should be selected from the following group:

<dl><dt>(1)</dt><dd> the salts with the following anions: Chloride, plus anions inorganic oxoanionic elements, of these especially sulfates, carbonates, phosphates, borates and aluminates. Organic anions based on electrolytes, such as lactates, acetates, bezoates, propianate, tartrate, citrate, amino acids and their salts and others plus. Similar effects are also obtainable by tetraacid. acetic acid of ethylene diamine and its salts.As cations will be preferable to use metal alkylammonium ammonium salts alkali metal alkaline earth, magnesium, iron or inon of zinc It is not necessary to make any mention that in Cosmetics can only be used physiologically electrolytes harmless Among them, chloride will be especially preferred potassium, cooking salt, magnesium sulfate, sulfate Zinc and its mixtures.</dd></dl>

According to the invention, the electrolyte (s) it is appropriate to select them from group (2), among which are:

<dl><dt>(2)</dt><dd>Certain ultraviolet filter substances present mostly as water soluble alkaline salts, especially those that carry in their molecular structure one or several groups sulfuric acid or sulfonate groups:</dd></dl>

<dl><dt /><dd>Acid 2-Phenylbenzylmidazole 5-sulfonic acid and its salts, especially sodium salt, potassium or its trietanol ammonium</dd></dl>

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<figref>1</figref>

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The sulfuric acid derivatives of the benzophenone, preferably the 5-sulfonic acid-2-hydroxy-4-methoxy-benzophenone acid and its salts, for example the corresponding sodium salts, potassium or triethanolammonium:

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<figref>2</figref>

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The sulphonic acid derivatives of 3-camphor benzylidene, such as acids benzosulfonic 4- (2-oxo-3-bornyledenmethyl) and its salts, for example the corresponding sodium salts, potassium or triethanolammonium:

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<figref>3</figref>

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Benzosulfonic acid 2-methyl-5- (2-oxo-3-bornylidenmethyl) and its salts, for example the corresponding sodium salts, potassium or triethanolammonium:

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<figref>4</figref>

Benzene 1,4-di (2 oxo-10-sulfo-3-bornylidenmethyl-) and its salts (the corresponding combinations 10-sultate, such as the respective salts sodium, potassium or triethanolammonium), also designated as acid -10- benzene-sulfonic 1,4-di (2-oxo-3-bornylidenmethyl):

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<figref>5</figref>

According to the invention it is still convenient to continue selecting the electrolyte (s) from the following group:

(3) between the amino acids and their salts or Your anions. Amino acids are components of the moisturizing factor natural (the so-called Natural Moisturizing Factor). The complement of the amino acids, especially the essential amino acids, they should be considered as advantageous since through the processes of Hydration facilitate the attachment of moisture to the skin.

Amino acids with dermatological effects or Especially effective cosmetics are glycine, alanine, valine, leucine, isoleucine, phenylalanine, tyrosine, proline, hydroxyproline, serine, threonine, cysteine, methionine, tryptophan, arginine

According to the invention, it is convenient to follow selecting them or group electrolytes:

(4) Of the acids α-hydroxycarbonics suitable for cosmetic and dermatologically, of acids α-ketocarbonics and the β-hydroxycarbonics and especially their salts, where the cations agree to select them from the group of ammonium ions, alkylammonium, alkali metal, earthy metal alkaline, magnesium-, iron- or zinc.

Acids α-hydroxycarbonics, which are suitable Cosmetically and dermatologically, they conform to the general formula

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<figref>6</figref>

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Acids β-hydrocarbons, especially indicated Cosmetically and dermatologically, they conform to the formula general

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<figref>7</figref>

Acids α-ketocarbons, especially indicated Cosmetically and dermatologically, they conform to the formula general

<figref>8</figref>

where, in each case R 'and R' ' independently select each other from the groups following

<dl><dt>(a1)</dt><dd>H-,</dd></dl>

<dl><dt>(a2)</dt><dd>C 1-25 -alkyl-, branched or unbranched.</dd></dl>

<dl><dt>(a3)</dt><dd>with one or more carboxyl groups and / or hydroxy groups and / or aldehyde groups and / or oxo groups (keto groups) C 1-25 -alkyl-substituted, branched or unbranched,</dd></dl>

<dl><dt>(a4)</dt><dd>phenyl-,</dd></dl>

<dl><dt>(to 5)</dt><dd>with one or more carboxyl groups and / or hydroxyl groups and / or groups C 1-25 branched alkyl and / or unbranched with phenyl-substituted, or where the atom α-carbon and the atom β-carbon of acids β-hydroxycarbonics with R 'and R' 'form together a</dd></dl>

<dl><dt>(a6)</dt><dd>unsubstituted cycloalkyl group or aryl group with 3 to 7 ring atoms or a</dd></dl>

<dl><dt>(a7)</dt><dd>carboxyl group with one or several and / or hydroxyl groups and / or oxo groups (keto groups) and / or groups C 1-25 branched alkyl and / or unbranched from the substituted cycloalkyl group or aryl group with 3 to 7 ring atoms and, where acids α-hydroxycarbonics or acids β-hydroxycarbonics or acids α-ketocarbonics in certain cases may be present in the form of its salts, physiologically compatible.</dd></dl>

Within the framework of the present invention, it is also advantageous the use of acids α-hydroxycarbonic acids β-hydroxycarbonics and acids α-ketocarbonics, where these are also They have introduced representing their salts or anions:

Salicylic acids (also acidic 2-hydroxybenzoic acid, spiric acid), which characterized by the structure

<figref>9</figref>

As is known salicylic acid acts antibacteriologically and keratolytically, intervening in the Composition of some cosmetic or pharmaceutical preparations.

Acids α-hydroxycarbonics referred to The invention should be selected from the following classes of substances:

<dl><dt>(b1)</dt><dd>fatty acids α-hydroxy, where these in turn agree especially select them from the acid group C_ {10-18} -alkylcarbons,</dd></dl>

<dl><dt>(b2)</dt><dd>saccharic acids α-hydroxy of sugar, fructo acids α-hydroxy aliphatics,</dd></dl>

<dl><dt>(b3)</dt><dd>acids unsubstituted aromatic α-hydroxycarbons (eg tonsillar acid) or</dd></dl>

<dl><dt>(b4)</dt><dd>acids α-aromatic hydroxycarbonics replaced.</dd></dl>

Fatty acids α-hydroxy included in item (b1) should select them specifically from the group

- of acids α-hydroxycarbonics, according to the formula

<figref>10</figref>

me

- of acids α-hydroxy-isocarbonics, according to the formula

<figref>11</figref>

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me

- of acids α-hydroxy-anteisocarbonics, according to the formula

<figref>12</figref>

where n always represents a less than 7.

It is also advantageous to use mixtures of such aliphatic α-hydroxycarbonic acids, especially in the form of mixtures of the wax acid of the wool, in which the acid content α-hydroxycarbonics is 20 to 30% by weight referred to the total composition.

Saccharic acids α-hydroxy included in point (b2) should be selected especially from the group of

<dl><dt>-</dt><dd> The aldonic acids, eg gluconic acid, acid galactonic</dd></dl>

<dl><dt>-</dt><dd> The aldaric acids, eg glucaric acid, galactaric acid (but also fruit acids, tartaric acid, which it also falls under the definition of the altaric acids)</dd></dl>

<dl><dt>-</dt><dd> The uronic acids, eg glucuronic acid, acid galacturonic</dd></dl>

<dl><dt>-</dt><dd> He glycerinic acid</dd></dl>

Aliphatic acids α-hydroxy of fruits corresponding to the point (b2) it is appropriate to select them specifically among those in the group of malic acid, lactic acid, citric acid and acid Tartaric

Malic acid (hydroxysuccinic acid) is characterized by the following chemical structure:

<figref>13</figref>

Lactic acid (acid 2-hydroxypropyan) is characterized by the following chemical structure:

<figref>14</figref>

Citric acid (acid 2-hydroxy-1,2,3-propantricarbon) It is characterized by the following chemical structure:

<figref>15</figref>

As is known, citric acid is used as buffer or compensator in cosmetic preparations and / or dermatological, but also as a synergistic agent for antioxidants in skin and hair cosmetics.

Tartaric acid (dihydroxysuccinic acid) is characterized by the following chemical structure:

<figref>16</figref>

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Α-ketocarbonic acid preferred is pyruvic acid (acid α-oxopropanic). This one is characterized by following structure:

<figref>17</figref>

The total amount of one or more electrolytes in cosmetic or dermatological formulations ready to be used, it should be less than 5% referred to the total weight of the preparation, although it is preferred that it be adjusted between 0.5 and 2.0% by weight of the total mentioned.

In the sense of the present invention, it is preferred especially stabilize water / oil pickering emulsions by adding the electrolytes to which the invention.

On the other hand it is advantageous, although it is not mandatory, that the Pickering emulsions referred to in the invention, contain other auxiliary products, which may further increase the stability of these preparations, for example, with substances that will be selected from the group of waxes and / or oil thickener products such as hydrocolloids

It is also convenient that when Pickering emulsions referred to in the invention contain auxiliary products, which can contribute to reducing or preventing a feeling of dryness or dry skin after application, although the main purpose of these substances may be another Preferably these substances are selected by example, from the group of derivatives of s-triacin, asymmetrically substituted, of the cyclodextrin, film-forming agents and polymers moisturizers, for which purpose such substances may be present both in isolation and in mixture.

The cosmetic characteristics of emulsions Pickering to which the invention relates, may for example, still be further improved, so that in the oil phase oils are also used, which have a viscosity of less than 30 mPa \ cdots, or especially less than 20 mPa \ cdots (determined with a rheometer from the firm Contraves (Rheomat 108E) with a shear rate of 500 / s and a temperature of 25 ° C).

Microfine particles

The amphiphilic character of the particles microfinas to which the invention relates, shows for example as These are dispersible in both water and oil.

It is convenient to choose the average diameter of the particles to be used between 1 nm and 200 nm, being especially favorable that the selection is made between 5 nm and 100 nm.

It is also advisable that, the concentration of All amphiphilic particles exceed 0.1% by weight, referred to the total weight of the preparation although it is convenient to choose especially that it is between 0.1% and 30% by weight, based on weight total mentioned.

In the sense of the present invention, they are specially indicated all the particles that are appropriate to stabilize water / oil pickering emulsions as well as oil / water emulsions. Basically essential for the present invention is the eventual natural form, which the particles will present modified.

For stabilization of emulsions Pickering pigment particles are preferably used practically pure and unhandled, especially those that can also be used as dyes in the industry food and / or as ultraviolet radiation absorbers in sunscreen products. Zinc oxide pigments distributed by Merck, are for example especially indicated as well as those that can be obtained with the designation commercial of neutral zinc oxide from Harmann &amp; Reimer or NanoX from Harcros Chemical Group.

In the sense of the present invention, the Pickering emulsions are also advantageously stabilized by inorganic pigments, which have received a surface treatment water-repellent ("gecoatet") that is, that have been coated, with which simultaneously creates the amphiphilic character or respectively it is maintained. This surface treatment can consist, in which pigments, following known processes, are endowed of a thin hydrophobic layer.

Another form of coating suitable for inorganic pigments consists of treating them with dimethylpolysiloxane (also: dimeticone), a completely methylated mixture, of linial siloxane polymers that finally block with trimethylsiloxy units. Especially advantageous in the sense of the present invention are zinc oxide pigments, which are follow this process.

It is also advantageous to coat the pigments inorganic with a mixture of dimethylpolysiloxane, more specifically dimethylpolysiloxane with an average chain length of 200 to 350 units of dimethylsiloxane and silica gel, which is also designates as symmetry. Especially advantageous is when inorganic pigments are additionally coated with hydroxide of aluminum or aluminum oxyhydrate (also alumina, CAS-No .: 1333-84-2). Also especially advantageous is also titanium dioxide, coated with symmetry and alumina, where the coating may also contain water. An example in this case is titanium dioxide under the name Eusolex T2000 commercial that can be purchased at Merck.

Suitable in the sense of the present invention, it is also the use of a mixture of different types of pigments either inside glass, for example as mixed iron oxide, as well as by combination of various types of pigments within a formulation

The Pickering emulsions to which the invention, preferably stabilized by particles of boron nitride, for example with boron nitrides related to continuation:

<dl><dt><i>Tradename</i></dt><dd><i>Distributed by</i></dd></dl>

<dl><dt>Boron Nitride Powder</dt><dd>Advanced Ceramics</dd></dl>

<dl><dt>Boron Nitride Powder </dt><dd>Sintec Keramik</dd></dl>

<dl><dt>Soft wax </dt><dd>Kawasaki</dd></dl>

<dl><dt>Boron Nitride HCST </dt><dd>Stark</dd></dl>

<dl><dt>BH® Trés </dt><dd>Carborundum</dd></dl>

<dl><dt>Wacker-Bomitruro BNP</dt><dd>Wacker-Chemie</dd></dl>

It is convenient to select the average diameter of Boron nitride particles used, below 20 um, being even more convenient that they are less than 15 \ mum.

Pickering emulsions in the sense of present invention, they are preferably stabilized by particles of boron nitride, which are treated superficially ("gecoatet"), turning them into hydrophobic, with which simultaneously the amphiphilic character is created or maintained if They already had it.

An advantageous coating of the particles of boron nitride, is achieved with dimethylpolysiloxane (dimethicon). Perfectly indicated is for example the one that can be purchased at Carborundum under the trademark Trés BH® UHP 1106, which these are boron nitride particles treated with dimethicon

Perfectly indicated is a coating of boron nitride particles with polymethylhydrogensiloxane, a linear polysiloxane, which is also designated as methicon. The boron nitride particles treated with methicon are advantageous for example, those obtained from Carborundum under the trademark Trés BN® UHP 1107.

It is also advantageous to stabilize the Pickering emulsions to which the invention relates, with particles Polymeric microfines.

Polymeric microfine particles recommended within the meaning of the present invention, are for example polycarbonates, polyethers polyethylene, polypropylene, chloride of polyvinyl, polystyrene, polyamides, oliacrylates and others Similar.

According to the invention, they are recommended for example microfine polylamide particles, which can be purchased under SP-500 trademark of TODAY. As well Recommended are polyamide 6- particles (also: Nylon 6) or polyamide 12- (also: Nylon 12). Polyamide 6 comes from ε-aminocapronic acid (6-aminoexanic acid) or ε-caprolactam from polyamide [poly (ε-caprolactam)], and polyamide 12 which is a poly (ε-laurilactam) of the ε-laurilactam. In the sense of The present invention recommends, for example, Orgasol® 1002 (polyamide 6) and Orgasol® 2002 (polyamide 12) from ELF ATO-CHEM.

Other recommended polymer particles are microfine polymethacrylates. Particles that for example can purchased under the trademark POLYTRAP® of DOW CHEMICAL

Especially recommended although not mandatory, is that microfine polymer particles used, they are superficially coated. This treatment superficial may consist of pigments, for a known procedure, provide a thin hydrophilic layer. The most recommended coatings consist for example in TiO 2, ZrO 2 or also of other polymers as per example polymethyl methacrylate.

The microfine polymer particles to which the present invention is concerned, they are especially suitable as well as also those described in the US patent declaration 4,898,913 obtainable by the procedure to carry out the hydrophilic coating of polymer particles hydrophobic

It is convenient to select the average diameter of the microfine polymer particles used, below 100 µm, especially recommending that it be less than 50 \ mum. On the other hand, it is essentially insignificant in that form the polymer particles used are presented, whether inserts, rods, balls, etc.

It is also advantageous that emulsions Pickering to which the invention relates, are stabilized by modified polysaccharides.

The modified polysaccharides in the sense of present invention are obtained for example by reaction of starch with bi- or polyfunctional reagents or with oxidizing agents in Widely polymeric developmental reactions.

Such reactions are essentially based on transformations of hydroxy groups of polyglucan by etherification, esterification or selective oxidation. In addition to this, for example, the so-called ethers and esters of the starch, corresponding to the general structural form following:

<figref>18</figref>

where R can represent pe a hydrogen and / or an alkyl and / or aralkyl moiety (in the case of the ether of starch) or a hydrogen and / or an organic acid residue and / or inorganic (in the case of starch ester). Starch ether and the starch ester, are within the meaning of the present invention, specially modified polysaccharides utility.

Among the especially useful starch ethers These include, for example, those that can be obtained by etherification of the starch with diureatetramethyllacetylene and those that can be designated as non-mucilaginous amyl (non-native starch).

Also very suitable are starch esters and its salts, for example sodium salt and / or semi-ester aluminum of poorly substituted starch especially sodium starch, n-octenyl succinate of structural formula (I), in where R is characterized by the following structure:

<figref>19</figref>

and in which, pe under the brand Amiogum® 23 can be obtained at CERESTAR as well as Aluminum starch, octenyl succinate, can be purchased specifically under the trademark Dry Flo® Elite LL and Dry Flo® OC in the firm CERESTAR

It is convenient to choose the average diameter of modified polysaccharide particle, employed, being less than 20 µm, or especially recommended that you choose lower at 15 µm.

The list of the mentioned polysaccharides modified, which according to the present invention can stabilize the Pickering emulsions, logically it is limiting. Polysaccharides modified in the sense of the present invention, can be obtained by multiple known procedures, both chemical in nature as well as physics.

Amphiphilic particles above mentioned, are especially suitable for both stabilization of Pickering W / O emulsions (water in oil) as also for stabilization of Pickering emulsions O / W / oil in water). Particles will be listed below. microfines according to this invention, which serve to stabilize especially effective one of both types of W / O emulsion or O / W

Pickering W / O emulsions (water / oil)

The fraction corresponding to the aqueous phase of the Pickering W / O emulsions to which the invention relates, are choose from the order of 0.5 to 75% by weight, based on the total weight of the formulation

For stabilization of emulsions Pickering W / O, silicate is also particularly advantageous magnesium (also: talcum), which can be acquired specifically with the Talco Micron trademark of Grolmann.

Pickering O / W emulsions (oil / water)

The fraction corresponding to the fatty phase of the Pickering O / W emulsions referred to in the invention are choose from the order of 0.5 to 75% by weight, based on the total weight of the formulation

For stabilization of emulsions Pickering O / W, within the meaning of the present invention are also the practically pure pigment particles without manipulation, specifically the titanium dioxide pigments, and especially those that can be purchased under the trademark KRONOS® 1171 (Tio_ {2}) of the firm Kronos Titan.

Pickering O / W emulsions in the direction of present invention, they stabilize in a particularly favorable way with metal oxide particles, which are coated ("gecoatet") with aluminum hydroxide and / or silicon dioxide. As preferred embodiments, they are for example the particles of titanium dioxide, which can be purchased under the EUSOLEX® brand TA from Merck.

Also favorable, although not mandatory, according to The invention is the fact of combining microfine particles with amphiphilic particles, which according to the cases also contribute to the stabilization of Pickering emulsions.

Such particles are for example pigments of titanium dioxide, which are coated with octylsilanol and / or silicon dioxide particles, which receive a treatment hydrophobic surface. Silicon dioxide particles suitable, for example, are spherical polyalkylsilsesquioxane, which are mentioned in the text of the European publication 0 686 391. Such polyalkylsilses-chioxane particles are for example, obtainable with the trademark

Aerosil R972 and Aerosil 200V from Degussa. The suitable titanium dioxide particles correspond to the T805 trademark and can also be purchased from the firm Taste

The Pickering emulsions to which the invention, can serve as a basis for cosmetic formulations or dermatological These can be formulated as usual and used for example for the treatment and care of the skin, to cosmetic mode for lips, as a deodorant and as a product for makeup or makeup removal in dermatological preparations decorative as well as prepared protective against light. For use, cosmetic and dermatological preparations a those referred to in the invention are applied to the skin in quantity enough and in the usual way as cosmetics is applied.

In this way, for example, the cosmetic or dermatologically topical preparations in the sense of the present invention, according to its cream-like structure skin protectors, cleansing milk, protective lotions sunscreens, nutrient creams, day or night creams, etc. In case necessary, it is possible and convenient to use the preparations at which relates to the invention as a basis for formulations Pharmaceuticals

Cosmetic and dermatological preparations a those referred to in the invention may contain auxiliary products cosmetics, such as those generally used in such preparations, eg preservatives, bactericides, perfumes, antifoaming substances, coloring products such as pigments that They have a coloring effect, thickening products, products softeners, moisturizers and / or substances to retain moisture, fats, oils, waxes or other usual components of a cosmetic or dermatological formulation such as alcohols, polyols, polymers, foam stabilizers, electrolytes, organic solvents or derivatives of the silicone.

Pickering emulsions according to the invention, may also contain thickener products, to improve tactile characteristics of emulsions.

The Pickering emulsions to which the invention, may also contain antioxidants in particular. According to the invention, all suitable antioxidants can be used those used for cosmetic applications and / or dermatological

It is convenient to select antioxidants from group consisting of amino acids (eg glycine, histidine, tyrosine, tryptophan) and its derivatives, imidazole (eg acid urocaninic) and its derivatives, peptides such as camosin-D, carnosine-D, carnosine-L and its derivatives (eg anserine), caratinoids, carotin (eg carotin-?, carotin-?, lycopene) and its derivatives, acids chlorogens and their derivatives, liponic acids and their derivatives (eg dihydroliponic acid), aurothioglucose, propylthioracil and other thiols (eg

Thioredoxin, glutathione, cysteine, cystine, cystamine and its glyceryl-, glycosyl- esters, N-acetyl-, methyl-, ethyl-, propyl-, amyl-, butyl-, and lauryl-, palmitoyl-, oleyl-, γ-linoleyl-, γcholesteryl- as well such as its salts, dialurylthiodine propionate, distearyl thiodine, thiodipropionic acid and its derivatives (ester, ether, peptide, lipid, nucleotide, nucleoside and salts) as well as sulfoximin combinations (eg sulfoximin of butionin, sulfoximin from homocysteine, butionin-sulfone, sulfoximin penta-, hexa-, heptationin) in very low compatible dosages (eg pmol up to \ mumol / kg), plus chelators- (metallic) (eg acid α-hydroxy fatty acid, palmitinic acid, acid phytinic, lactoferrin), α-hydroxy acids (eg citric acid, lactic acid, malic acid), humic acid, gallic acid, gallic extracts, bilirubin, biliverdin, EDTA, EGTA and its derivatives, unsaturated fatty acids and their derivatives (eg γ-linolenic acid, acid linoleic, oleic acid), folic acid and its derivatives, ubichinone and ubichinol and its derivatives, vitamin C and derivatives (eg ascorbyl palmitate, Mg-ascorbyl phosphate, ascorbyl acetate), tocopherol and its derivatives (eg acetate vitamin E), Vitamin A and derivatives (vitamin A palmitate) as well as the coniferyl benzoate of the benzoic resin rutinic acid and its derivatives, rutin? -glycosyl, acid ferulaic, furfurylidenglucitol, butylhydroxytoluene camosin, butylhydroxyanisole, nordihydroguajak resin acid, acid nordihydroguajaret, trihydroxybutyrophenone, hamic acid and its derivatives, mannose and its derivatives, zinc and its derivatives (eg ZnO, ZnSO_4) selenium and its derivatives (eg methioninselenium), stilbite and its derivatives (eg stilbite oxide, trans-oxide of stilbite) and the suitable derivatives according to the invention (salts, esters, ethers, sugars, nucleotides, nucleosides, peptides and lipids) of these substances mentioned.

The amount of the previously related antioxidant agents (one or more combinations) in the formulations referred to in the invention will become possible from 0.001 to 30% by weight, especially preferred that range of 0.05 to 20% by weight or even between 1 to 10% by weight referred to the total weight of the preparation.

As for vitamin E and / or its derivatives that represent the antioxidant (s), it is convenient to select their corresponding concentrations in the order of 0.001 to 10% in weight referred to the total weight of the formulation.

As for vitamin A and respectively Vitamin A derivatives as well as carotine and its derivatives respective, which represent the antioxidant (s), it is advised choose your respective order concentration between 0.001 to 10% in weight, based on the total weight of the formulation.

The preparations are also favorable Cosmetic and dermatological presented in the form of an agent sunscreen. These preferably contain at least one UV-A radiation filtering substance and / or as minimum a radiation filtering substance UV-B and / or at least one other inorganic pigment of the group of oxides of iron, zirconium, silicon, manganese, aluminum, cerium and mixture thereof as well as variations in which the oxides represent the active agents.

However, it is also advantageous in the meaning of the present invention, prepare such formulations Cosmetic and dermatological, whose main objective is not the protection against sunlight, and yet they contain protective substances against ultraviolet radiation. So by example in ordinary day creams add substances UV-A ultraviolet radiation filters as well as well as UV-B radiation.

It is appropriate that the preparations to which relates the invention, contain radiation absorbing substances UV in the UV-B range, where the quantity total filtering substance reach pe from 0.1% up to 30% by weight, or preferably 0.5 to 10% by weight with preference especially contain from 1.0 to 6.0% by weight, based on weight Total formulation, to prepare cosmetic formulations, which they will protect the hair or the skin from the entire range of radiation ultraviolet

If the emulsions to which the invention contain filtering substances for radiation UV-B, these may be oil soluble or water soluble. According to the invention, the filtering substances UV-B oil soluble especially indicated, they are pe

- camphor derivatives 3-benzylidene, preferably camphor 3 - (- 4-methylbenzylidene), camphor 3-benzylidene; acid derivatives 4-aminobenzoic acid, preferably the (2-Ethylhexyl) 4- (dimethylamino) acid ester benzoic, benzoic acid amyl ester 4- (dimethylamino);

- cinnamic acid ester, preferably the 2-ethylhexyl) acid ester 4-methoxycinnamic acid isopentyl ester 4-methoxycinnamic;

- salicylic acid ester, preferably (2-ethylhexyl) salicylic acid ester, (4-Isopropylbenzyl) salicylic acid ester, homomentyl ester of salicylic acid.

- benzophenola derivatives, preferably 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-4'-methylbenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone;

- benzalmalonic acid ester, preferably di- (2-ethylhexyl) acid ester 4-methoxybenzalmalonic,

- with respect to the C3 axis of symmetric triacin derivative of the triazine basic body, preferably tris- (2-ethylhexyl ester) of the acid tris-benzoic 4,4 ', 4' '- (1,3,5-triacin-2,4,6-triyltriimino),

- benzotriazole derivatives, preferably the phenol-2,2'-methylene-bis- (6- (2H-benzotriazol-2-yl) -4- (11,1,3,3-tetramethylbutyl).

- as well as polymers linked to UV filters

The ideal UV-B filters, Water soluble are eg:

- acid salts 2-phenylbenzimidazole 5-sulfonic acid such as its sodium, potassium or triethanolammonium salts, as well as the sulfonic acid itself;

- sulphonic acid derivatives of the benzophenone, preferably acid 5-sulfonic-2-hydroxy-4-methoxybenzophenone and its salts;

- acids sulfonic-camphor derivatives 3-benzylidene, such as benzol acid sulfonic-4- (2-oxo-3-bornylenmethyl), the acid sulfonic-5- (2-oxo-3-bornylidenmethyl) and Your salts

The list of the mentioned filters UV-B, which can be used in emulsions Pickering to which the invention refers, logically it is not limited Only these.

It may also be convenient to use filters UV-A in Pickering emulsions to which refers to the invention, which are currently involved in usual formulations in cosmetics. As for these substances these are preferably derivatives of dibenzoyl methane, specifically from 1-3 dion propane-3- (4'-methoxyphenyl) -1- (4'-ter.butyl-phenyl) -1,3-dion and 1-3 propane dion 3- (4'-isopropylphenyl) 1-phenyl.

Other substances recommended as filters UV-A are acids 3,3'-5,5'-tetrasulfonic acid felinelo-1,4-bis- (2-benzimidazyl):

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<figref>20</figref>

and its salts, especially the corresponding sodium, potassium or triethanolammonium, and in particular the bis sodium salt of the acid 3,3'-5,5'-tetrasulfonic acid phenylene-1,4-bis- (2-benzimidazyl):

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<figref>21</figref>

as well as benzene 1,4-di (2-oxo-10-sulfo-3-bornylidebmethyl) and its salts (especially those corresponding to combinations 10-sulfate and especially the corresponding salts sodium, potassium or triethanolammonium), which are also designated as acid di-2-oxo-3-bomilidenmethyl-10-sulfonic of benzene that are distinguished by structure following:

<figref>22</figref>

Also preparations containing filters UV-A, are the subject of this invention. Can be used amounts used for combinations UV-B

Advantageously they can also be used preparations how, those referred to in the invention, by way of bases for deodorants, cosmetics or antiperspirants, so that the present invention in a special embodiment, concerns Pickering emulsions as bases for deodorant products Cosmetics

Cosmetic deodorants serve to suppress the body odor that forms when sweat, fresh, of itself, No smell, it is replaced by microorganisms. Deodorants Usual cosmetics are based on different active ingredients.

With so-called antiperspirants, you can reduce the development of sweat through astringent products, predominantly based on aluminum salts such as aluminum hydroxychloride (aluminum hydrochloride) - which reduce The transformation of sweat.

Through the use of antimicrobial substances in cosmetic deodorants, bacterial flora can be reduced on the skin. For this, in ideal cases, they should only be reduced effectively the microorganisms that cause odors. He sweat flow itself, is not influenced by it and in the best of cases only decomposition temporarily stops sweat microbial. Also the combination of astringents, with antimicrobial active substances, can be used for the same or other formulation.

All active substances suitable for Deodorants or antiperspirants can be used effectively, for example odor masks as usual perfume components, odor absorbers, for example the stratified silicates described in the document DE-P 40 09 347 patent declaration, of which Montmorillorite, kaolinite, ilite are especially indicated, beidellite, nontronite, saponite, hektorite, bentonite, smectite, and others such as zinc salts of ricinol acid. The antiseptic products are also suitable to be added as W / O mother emulsion (water / oil) according to the invention. Substances recommended should be indicated for example 2'-hydroxy diphenyl ether-2,4,4'-trichloro (Irgasan), the hexane-1,6-di- (4.chlorophenylbiguanide) (chlorexidine), 3,4,4'-trichlorocarbanilide, Quaternary combinations of ammonium, clove essence, oil mint, thyme oil, triethyl citrate, fern oil (1-oil 3,7,11-trimethyl-2,6,10-dodecatriene) as well as the active substances described in the documents of Patent publication DE-37 40 186, DE- 39 38 140, DE-42 04 321, DE-42 29 707, DE-43 09 372, DE-44 11 664, DE-195 41 967, DE-195 43 695, DE-195 43 696, DE-195 47 160, DE-196 02 108, DE-196 02 110, DE-196 02 111, DE-196 31 003, DE-196 31 004 and DE-196 34 019 and the described in patents DE-42 29 737, DE-42 37 081, DE-43 24 219, DE-44 29 467, DE-44 23 410 and DE-195 16 705 as well as combinations of active substances It is also advisable to use carbonate hydrogensodium

The relation of the mentioned substances active or their combinations, not logically intended to be restrictive

The amount of the active substance in the antiperspirants or deodorants (one or more combinations) in the formulation, preferably reach 0.1 to 30% by weight, if either it is preferred that it reaches 0.1 to 20% by weight or at best cases of 1 to 10% by weight referred to the total weight of the formulation.

The following examples will serve as clarification for the present invention, without implying any limitation. The numerical values ​​of the examples mean percentages by weight, referring to the total weight of each of the formulations

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Example

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<figref>23</figref>

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(Continuation)

<figref>24</figref>

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(Continuation)

<figref>26</figref>