ES2620455T3 - Compositions comprising solid particles trapped in collapsed polymer microspheres and manufacturing processes - Google Patents

Abstract

A method for modifying or treating solid particles comprising: (a) forming a gelled mixture by mixing, either simultaneously or successively in any order: (1) hollow microspheres that each comprise a deformable polymeric shell that is trapped inside it an expandable fluid, (2) a polar organic solvent capable of swelling, but not dissolving, the polymeric shells of the hollow microspheres, the acetone polar organic solvent, and (3) solid particles, in which the polar organic solvent molecules they enter between the polymeric chains of the polymeric shell and interrupt the intermolecular bonds between the chains, forming micro-channels in the swollen polymeric envelopes to allow the entry of the solid particles into the hollow microspheres and the exit of the expandable fluid from them, forming in by virtue of this microspheres, each comprising a collapsed polymeric shell having a average particle size within the range of about 1 to 15 micrometers, according to a Malvern particle size analyzer, in a gelled state and having one or more of said solid particles trapped therein; (b) degassing the gelled mixture under reduced pressure or under vacuum conditions to remove the expandable fluid from the gelled mixture; (c) introducing water into the degassed gelled mixture with sufficient agitation to inactivate the gelled mixture so that the microspheres separate from each other; and (d) remove acetone and water to result in a dry powder that flows freely.

Description

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Compositions comprising solid particles trapped in collapsed polymer microspheres and manufacturing processes

Field of the Invention

The present invention relates to topical compositions comprising components in stabilized particles, as well as processes for their manufacture.

Background of the invention

Cosmetic or topical compositions normally comprise one or more particulate components, such as for example pigments or dyes, fillers, thickeners, sunscreen agents and the like.

Said particulate components are generally insoluble in the corresponding solvent or velffculo system, and thus remain dispersed or suspended in cosmetic or topical compositions.

However, whenever changes in the pH and temperature of the surrounding environment occur, dispersed or suspended particles can agglomerate with each other and separate by precipitation from the composition. Also, the smaller the size of the particle, the greater the active surface area and the more susceptible are the components in particles of adverse interactions or interferences with other ingredients or components of the cosmetic or topical compositions, which can destabilize the cosmetic or topical compositions or reduce its overall efficiency.

WO 07/038404 describes a topical composition comprising hollow thermoplastic microspheres having at least one beneficial agent for the skin trapped inside. Said microspheres (commercially available under the Expancel® brand) can be coated with a polymeric coating. The microspheres have a hollow core that is occupied with a gas and at least a portion of said gas is replaced by a beneficial agent for the skin, using a solvent to open the pores on the surface. The solvent is not a strongly polar solvent (acetone is not recommended).

The US document 5,219,561 refers to a cosmetic composition in the form of compacted powders comprising a dispersion of EXPANCEL® mixed with pigments / powders, such as titanium dioxide, an oily phase and / or stability agents, as well as optional ingredients, mixing all it in combination and compacting later.

The US document 2007/071978 describes topical compositions comprising hollow thermoplastic microspheres for the delivery of beneficial agents for the skin trapped inside. These microspheres are available in the market with the Expancel DE or Expancel WE brand.

Therefore, there is a permanent need to treat and modify the particulate components of cosmetic or topical compositions in order to eliminate or mitigate the drawbacks described and improve the overall stability of the compositions without adversely affecting the chemical properties or physics of the components in particles. A: \ 31700 \ 31728 EP ELC \ 2 - EXAMINATION \ 31728EP-OA3-Notification 94 (3) CBE \ 31728EP description pages 1 to 2a.doc

There is also a need to improve the chemical and / or physical properties of the particulate components through a surface treatment or modification.

Summary of the invention

In one of its aspects, the present invention relates to a topical composition comprising a dispersion of microspheres in a velvet, cosmetically or pharmaceutically acceptable, said microspheres comprising a collapsed polymeric shell in which one or more solid particles are trapped.

In another of its aspects, the present invention relates to a microsphere comprising a collapsed polymeric shell in which one or more solid particles are trapped, the collapsed polymeric shell also being coated with a fluid impermeable membrane.

In yet another aspect, the present invention relates to a topical sunscreen composition comprising a dispersion of microspheres in a cosmetically or pharmaceutically acceptable velocity, each of the microspheres comprising a collapsed polymeric envelope in which one or more are trapped solid particles comprising titanium dioxide, zinc oxide or a combination thereof.

In yet another aspect, the present invention relates to a method for modifying or treating solid particles comprising:

(a) forming a gelled mixture by mixing either simultaneously or successively in any order: (1) hollow microspheres that individually comprise a deformable polymeric shell in which an expandable fluid is trapped, (2) a polar organic solvent capable of swelling , but not dissolve, the polymeric envelopes of the hollow microspheres, the polar organic solvent being acetone, and (3) solid particles, into which the molecules of the polar organic solvent enter between the polymeric chains of the envelope

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polymerizes and interrupts the intermolecular bonds between the chains, forming micro-channels in the swollen polymer envelopes to allow the entry of the solid particles into the hollow microspheres and the exit of the expandable fluid thereof, thus forming microspheres that individually comprise a shell collapsed polymer having an average particle size in the range of about 1 to 15 micrometers, according to a Malvern particle size analyzer, in a gelled state and having one or more of said solid particles trapped;

(b) degassing the gelled mixture under reduced pressure or under vacuum conditions to remove the expandable fluid from the gelled mixture;

(c) introducing water into the degassed gelled mixture with sufficient agitation to inactivate the gelled mixture to separate the microspheres from each other; Y

(d) remove acetone and water to result in a free flowing powder.

Other aspects and objectives of the present invention will become more apparent from the description, examples and claims set forth below.

Brief description of the drawings

FIG. 1 are schematic views of: (1) an untreated hollow microsphere with a deformable polymeric shell and an expandable fluid trapped therein; and (2) a microsphere containing a collapsed polymeric shell that has solid particles trapped inside and a liquid impermeable membrane that lines it above, which is formed through the treatment of the untreated hollow microsphere in accordance with a mode of realization of the present invention.

FIG. 2 is a Scanning Electron Microscopy (SEM) image of the microspheres formed by entrapment of TiO2 particles in EXPANCEL® microspheres in accordance with one embodiment of the present invention.

FIG. 3 is a graph showing the percentage of color changes (%) of an organic dye (Red 28) after 22 hours of exposure to ultraviolet (UV) light, providing the organic dye both alone and as a sample of control, as in combination with various types of TiO2 particles, including uncapsulated (or bare) TIO2 particles and particles of TO2 trapped in microsphere with oxidants and without oxidants, in accordance with alternative embodiments of the present invention.

FIG. 4 shows the UV absorbance spectra of sunscreen compositions containing uncapsulated (or bare) TiO2 particles or the microsphere-trapped TO2 particles of the present invention after exposure to UV light.

FIG. 5A shows the photo-absorbance curves of a sunscreen composition containing uncapsulated (or bare) TiO2 particles and avobenzone after exposure to UV light at various intensities.

FIG. 5B shows the photo-absorbance curves of a sunscreen composition containing the TiO2 particles trapped in the microsphere of the present invention and avobenzone, after exposure to UV light at various intensities.

Detailed description of the invention

The present invention provides stabilized particulate components that are useful in cosmetic or topical compositions, as well as methods for stabilizing particulate components. Specifically, the particulate components are trapped in polymeric microspheres that have an average particle size that is at least 10 times larger, preferably 20 times, more preferably 50 times, 100 being more preferably greater than the average particle size of the particles themselves. particulate components. Each of the microspheres comprises a collapsed polymeric shell that has one or more solid particles trapped inside. Preferably, the physical and / or chemical properties of the trapped solid particles that concern or that are associated with the action of the desired cosmetic or topical composition are not adversely affected, while significantly larger microspheres provide better structural and structural stability. space.

The entrapment of the solid particles is achieved in the present invention by first providing hollow microspheres with deformable polymeric shells that encapsulate an expandable fluid, which are then mixed, either successively in any order or simultaneously, with a polar organic solvent. capable of swelling, but not dissolving, the polymeric envelopes of the hollow microspheres and the solid particles to be trapped. By virtue of this, a gelled mixture is formed containing microspheres with polymeric envelopes in a gelled state, swollen enough to have micro-channels or holes formed therein to allow the entry of solid particles into the microspheres. Said micro-channels or holes in the swollen polymeric envelopes of the microspheres also allow the exit of the expandable fluid from the microspheres thereby causing immediate crushing or crumbling of the polymeric envelopes and trapping the solid particles inside the microspheres. Then, the expandable fluid and the polar organic solvent are removed from the gelled mixture. Preferably, but not necessarily, the collapsed polymeric envelopes are coated with a film-forming material to form a liquid impervious membrane above them, which serves to isolate the collapsed polymeric envelopes from the microspheres of any solvent from the surrounding environment that may swell. or otherwise affect the structural integrity of said polymeric envelopes. In this way, solid particles can be safely trapped inside the

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microspheres with minimal risk or no risk of escaping out.

The hollow microspheres as initially provided (ie, before mixing with the solid particles or the polar organic solvent) are preferably expandable hollow polymer microspheres, which individually contain a deformable polymeric shell that is gas tight and enclosed or encapsulated. Inside an expandable fluid. With heating, the enclosed or encapsulated fluid can expand volumetrically to exert pressure on the inner wall of the deformable polymeric shell. At the same time, the elevated temperature can cause the polymeric shell to soften, thereby allowing the entire microsphere to expand in a manner similar to a balloon.

The deformable polymeric shells of the hollow microspheres can be formed of any crosslinked or uncrosslinked, synthetic or natural polymer. If the polymer is crosslinked, it is preferably weakly crosslinked. Preferably, but not necessarily, the polymeric shells of the hollow microspheres comprise at least one synthetic polymer obtained by polymerization of one or more ethylenically unsaturated monomers to form homopolymers or copolymers of ethylenically unsaturated monomers or copolymers of ethylenically unsaturated monomers and one or more organics groups . Examples of ethylenically unsaturated monomers that are suitable include, for example, vinylidene chloride, vinyl chloride, acrylonitrile, acrylic acid and their corresponding aromatic or aliphatic esters of C1-C20, methacrylic acid and their corresponding aromatic or aliphatic esters of C1- C20, acrylamide, methacrylamide, vinyl pyrrolidone, alkenes such as styrene, ethylene, propylene, butylene, methylpentene, 1,3-butadiene and the like. The polymeric shells of the hollow microspheres can also be formed of suitable synthetic polymers, such as polyesters, polyamides, polyphthalamides, polyimides, polycarbonates, polyketones, cellulose acetate, polysulfones, phenylene polysulphides, phenylene polyoxides, lactic polyacidyl polystyrene , polyacrylonitrile, polyacrylamide, methyl polymethacrylate, polyacrylates and copolymers of the polymers listed. In a particularly preferred embodiment, the deformable polymeric shells of the hollow microspheres are formed of a copolymer of vinylidene chloride, acrylonitrile and / or methyl methacrylate.

The expandable fluid within the hollow microspheres of the present invention can be any suitable gas (eg air or nitrogen) or volatile liquid hydrocarbons (eg isobutane or isopentane). Preferably, the expandable fluid is selected from the group consisting of air, nitrogen, isobutane and isopentane. More preferably, the expandable fluid is isobutane or isopentane.

The hollow microspheres having deformable polymeric shells composed of a copolymer of vinylidene chloride, acrylonitrile and methyl methacrylate with an expandable fluid composed of isobutane or isopentane are commercially available under the trademark EXPANCEL® from Expancel, Inc. in Duluth, Georgia. EXPANCEL® hollow microspheres are available in various forms, eg dry, wet, unexpanded or pre-expanded. In the present invention, both dry non-expanded microspheres (EXPANCEL® DU) and expanded dry microspheres (EXPANCEL® DE) can be used to trap and stabilize solid particles. EXPANCEL® DU microspheres have an average particle size between about 6 and about 40 micrometers and a density of about 1-1.3 g / cm3. EXPANCEL® DE microspheres have an average particle size in the range of about 20 to about 150 micrometers and a density of about 0.03-0.07 g / cm3.

Any suitable polar organic solvent that can sufficiently swell, but not dissolve, the polymeric envelopes of the hollow microspheres can be used to treat the hollow microspheres described above. Examples of polar organic solvents that can be used in the practice of the present invention include, but are not limited to: dimethylformamide, dimethyl chloride, trichlorethylene (TCE), chloroform, methanol, ethanol, isopropanol, acetone, acetate ethyl, butyl acetate and methyl ethyl ketone (MEK). Most preferred in the present invention is acetone. After mixing with the untreated hollow microspheres, the polar organic solvent can swell the polymeric envelopes of the hollow microspheres significantly and thereby convert the gas-tight polymeric envelopes of the untreated hollow microspheres to the gelled state with multiple micro -channels or pores formed in them.

The solid particles to be trapped and stabilized in accordance with the present invention may consist of any particulate component that is commonly used in cosmetic or topical compositions, including, but not limited to: mineral pigments and fillers, such as talc, caolm, mica, bismuth oxychloride, chromium hydroxide, barium sulfate, methyl polymethacrylates (PMMA), boron nitride, nylon beads, polymer powders (eg BPD powders 500 polymer compounds crosslinked hexamethylene / trimethylol hexyl lactone and silica diisocyanate, commercially available from Kobo Products, Inc. in South Plainfield, NJ), silica, silica beads, coloring lacquers (eg aluminum or calcium), metal oxides ( eg black, yellow or blue iron oxide, chromium oxide, zinc oxide and titanium dioxide), physical and chemical sunscreen agents and other organic or inorganic powders or particles. Preferably, but not necessarily, the solid particles are composed of a material capable of generating oxygen free radicals and, more preferably, a metal oxide, such as zinc oxide or titanium dioxide. Solid particles can have any regular or irregular shape, such as spherical, cubic, cylindrical, flat, fibrous and the like. The average particle size of solid particles, as used in the present invention, should be significantly smaller than that of hollow microspheres, so that solid particles can easily enter and become trapped in

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The hollow microspheres. Preferably, the average particle size of the solid particles is less than 1 micrometer, more preferably from about 0.001 micrometers to about 0.1 micrometer, most preferably from about 0.01 to about 0.05 micrometers. A preferred concrete example of solid particles includes manganese modified titanium dioxide particles commercially available under the trade name Optisol ™ from Croda, Inc. in Edison, NJ.

The hollow microspheres, the polar organic solvent and the solid particles are mixed, as described, either simultaneously or successively, to form a gelled mixture. If mixed in succession, the ingredients can be added and mixed in any suitable order. For example, the hollow microspheres and solid particles can be mixed first, followed by the addition of the polar organic solvent to form a thick suspension. Also for example, the solid particles can be dispensed in the polar organic solvent first and then mixed with the hollow microspheres. According to another example, the hollow microspheres can be added to the polar organic solvent to form a gel first and then add the solid particles to the gel. In any case, all the ingredients are thoroughly mixed until a homogeneous mixture is formed. The weight ratio between the hollow microspheres and the polar organic solvent is preferably from about 1: 3 to about 1: 100, and more preferably from about 1:20 to about 1:50, so that the polymeric envelopes of the hollow microspheres they can swell sufficiently with the solvent. The weight ratio between the solid particles and the hollow microspheres can vary greatly between about 1:10 and about 100: 1, preferably between about 2: 3 and about 10: 1, and more preferably between about 1: 1 and about 2: one.

Since the polymeric sheaths of the hollow microspheres are composed of a non-crosslinked or weakly crosslinked polymer, as mentioned above, the polar organic solvent molecules, which are sufficiently small with respect to the polymeric molecules, can enter between the chains polymeric, interrupt intermolecular bonds between neighboring polymer chains and release polymer chains between sf. Consequently, the polymeric shells of the hollow microspheres are swollen with the polar organic solvent so that they form a gelled mixture containing porous networks of interconnected polymer chains that extend or disperse throughout the volume of the polar organic solvent. The polymeric envelopes of the microspheres in said gelled state cease to be gas-tight, and instead become porous, that is, with micro-channels large enough to allow the entry of solid particles into the sufficiently swollen microspheres. At the same time, the expandable fluid exits these microspheres through the micro-channels, causing the gelled polymeric envelopes to crush or crumble with the result of counter-shaped microspheres with a significantly smaller overall volume. In this way, the solid particles are trapped inside the collapsed polymeric envelopes of the counter-microspheres.

Said counter microspheres have an average particle size between about 1 and 15 micrometers and more preferably from about 5 micrometers to about 8 micrometers. The counter microspheres have a significantly smaller size than that of the untreated hollow microspheres. Likewise, the counter-microspheres cease to be hollow and, instead, are now loaded with solid particles, leaving no empty space or very little. At the same time, the polymeric envelopes of the microspheres remain in a gelled state, that is, swollen by the polar organic solvent. It is important to note that although the counter-microspheres of the present invention are morphologically and volumetrically modified through the gelation process, they remain as separate particles in the gelled mixture with little or no coalescence. Subsequent drying of the gelled mixture thus forms freely flowing powders that flow freely fine containing microspheres with well defined surface limits and the minimum agglutination or agglomeration.

The gelation process, as described herein, is fundamentally different from the perfectly known sol-gel process. In a normal sol-gel process, metal alcohol and metal chloride precursors are first solubilized to form a solution (sol) and then subjected to hydrolysis and polycondensation reactions to form a colloid system composed of solid particles dispersed in a solvent, followed by evolution towards the formation of an inorganic network containing a liquid phase (gel), which can be dried to remove the liquid phase from the gel thereby forming a porous material. In contrast, the gelation process of the present invention does not involve hydrolysis or polycondensation reactions, and forms a network of water-soluble polymer chains dispersed in the polar organic solvent.

The gelled mixture, as described, can be subjected to degassing, according to which, the gelled mixture is subjected to reduced pressure or vacuum conditions to remove the expandable fluid from the gelled mixture. Subsequently, a second solvent that is miscible with the polar organic solvent previously used to swell / gel the microspheres with sufficient agitation can be added to the degassed gel mixture in order to "inactivate" the gelled mixture by separating the swollen microspheres from each other. For example, when the polar organic solvent is acetone, the second solvent may be water, which is miscible with acetone. As a consequence of the immiscibility between the polar organic solvent and the second solvent, the microspheres become more separated in space from each other and, therefore, more dispersed. Said greater dispersion of the microspheres serves to minimize the risk of coalescence during the subsequent drying of the gelled mixture. The greater separation of the microspheres can be achieved through a filtration or centrifugation stage, which

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It is optional for the purposes of the present invention.

After the degassing and quenching steps, preferably, both the polar organic solvent and the second solvent are removed from the gelled mixture to form free flowing, dry powders containing the microspheres with the solid particles trapped inside. The removal of the polar organic solvent and the second solvent can be easily achieved through various separation and / or drying techniques perfectly known in the art, such as decantation, centrifugation, filtration, solvent extraction, air drying, vacuum drying. , lyophilization, spray drying, fluidized bed drying, drying with super-quantum fluid, and the like. Polymeric envelopes previously swollen with the polar organic solvent and which have become porous with the micro-channels that extend therein, contract significantly and lose their porosity after drying. In other words, after the drying stage, the micro-channels that have formed through the swollen polymeric envelopes of the microspheres during the gelation stage are closed, thereby safely trapping the solid particles inside. of the microspheres. To minimize the agglomeration between the dried microspheres, the resulting powders can also be subjected to grinding and sieving through one or more gratings.

To eliminate or minimize the possible risk of solid particles trapped out of the dried microspheres escaping, the resulting free flowing, dried powders are coated or otherwise superficially treated with a film-forming material that forms a membrane impervious to liquids on each of the dried microspheres. In this way, the microspheres are sealed before the solvents of the surrounding environment that can potentially swell the polymeric envelopes of the microspheres and cause the escape of the trapped solid particles.

In the present invention, any material capable of forming a liquid impermeable membrane can be employed, either hydrophilic or hydrophobic. Suitable materials include film-forming materials, such as synthetic or natural homo- or copolymers composed of ethylenically unsaturated monomers, including acrylic acid, methacrylic acid or its C1-C10 alkyl esters, ethylene, propylene or vinyl pyrrolidones, silicone gums that are organosiloxanes that generally have a viscosity in the range of about 200,000 to 10,000,000 centipoise at room temperature; animal, vegetable, silicone or mineral waxes, organic esters or hydrocarbon oils, or silicone resins such as trimethylsiloxy silicate or polymethylsilylsquioxane; cellulosic polymers; fatty acids (eg fatty carboxylic acid having about 6 to 40 carbon atoms that can be liquid, solid or semi-solid at room temperature), fatty alcohols (eg alcohols having 6 to 50 atoms carbon that can be liquid, solid or semi-solid at room temperature) and inorganic materials. Preferably, but not necessarily, the film-forming material comprises an alkyl silicone polymer or, more specifically, a fatty alkylmethylsiloxane, such as cetyl dimethicone, stearyl dimethicone or behenyl dimethicone, or other modified siloxanes, such as polyoxyalkylened silicones, typically called dimethicone silicones. copolyol or cetyl dimethicone copolyol. For example, a polymethylhydrogensiloxane, commercially available from Dow Corning Corporation in Midland, MI under the tradename Dow Corning® MH 1107 may be used as a film forming material in the present invention. This polymethylhydrogensiloxane material is a colorless silicone liquid that can be thermally cured in the presence of a catalyst (e.g. zinc octoate, iron octoate, dibutyl stan dilaurate and stan octoate) to form a liquid impermeable membrane , solid composed of cross-linked dimethicone on the microspheres of the present invention. They can also be used as film-forming materials in the present invention to form a liquid impervious membrane on microspheres, for example, commercially available silicone copolymers by Dow Corning under the trade name BIO-PSA, which are formed by reacting a siloxane resin with a diorganosiloxane. Among the different types of BIO-PSA materials available from Dow Corning, Dow Corning® 7-4404, 7-4405 and 7-4411 fluids are particularly preferred (containing trimethylated silica treated with dimethylsiloxane and dispersed in a cosmetically acceptable solvent such as octamethyltrisiloxane , isododecane or decamethyltetrasiloxane).

The resulting microspheres with the solid particles trapped inside and the liquid impermeable membrane that cover them above may have an average particle size in the range between about 1 and about 50 micrometers, more preferably between about 1 and about 15 micrometers, most preferably between about 5 and about 8 micrometers, as determined with a Malvern particle size analyzer, available from Malvern Instrument in Worcestershire, UK. The trapped solid particles may constitute from about 10% to about 90% of the total weight of the resulting microspheres, more preferably from 30% to about 75% of the total weight, most preferably from about 40% to about 60% of the total weight. . The polymeric shells may constitute from about 5% to about 75% of the total weight of the resulting microspheres, more preferably from 10% to about 60% of the total weight, most preferably from about 30% to about 50% of the total weight. The liquid impervious coating material may constitute from about 1% to about 30% of the total weight of the resulting microspheres, more preferably from about 5% to about 20% of the total weight, and most preferably from about 10% to approximately 15% of the total weight.

FIG. 1 shows illustrative schematic views of an untreated hollow microsphere 10 and a microsphere 20 in accordance with an embodiment of the present invention, which has been formed by treating the microsphere.

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hollow untreated 10 according to the procedure described above. Specifically, the untreated hollow microsphere 10 includes a gas-tight and deformable polymeric shell 12 with an expandable fluid 14 trapped therein. The diameter of the untreated hollow microsphere 10 is approximately 20 micrometers. In contrast, the microsphere 20 of the present invention includes a collapsed polymeric shell 22 with solid particles 24 trapped therein and a liquid impermeable membrane 24 that lines it above. The diameter of the microsphere 20 is significantly smaller than that of the untreated hollow microsphere 10 and is approximately in the range of about 5 to about 8 micrometers.

FIG. 2 shows a Scanning Electron Microscopy (SEM) image of EXPANCEL® microspheres collapsed with TiO2 particles trapped therein, formed in accordance with the treatment procedure of the present application, as described above. The SEM image was taken with a 15KX magnification.

When formulated in topical compositions, solid particles trapped in the microsphere of the present invention provide various advantages and benefits that are not available in their "naked" or uncapsulated equivalents. For example, since the trapped solid particles are sealed against potential destabilizing or degrading ingredients of the topical composition, they are significantly more stable than their "naked" or non-encapsulated equivalents. Likewise, if the solid particles are potentially capable of degrading or otherwise interfering with other active principles of the topical composition, entrapment of said solid particles serves to reduce interference or degradation and improves the overall stability of the topical composition. The entrapment in the microspheres can also alter the hydrophobia or hydrophilicity of the solid particles and allow such solid particles to be formulated in the aqueous, oily or silicone phases, which are normally incompatible with the "naked" or uncapsulated solid particles. . It is important to note that the desired chemical and / or physical properties of solid particles should remain substantially intact with the entrapment described above.

Since the microspheres of the present invention are formed by immobilization of the solid particles in the previously formed hollow polymer microspheres that are subsequently crushed during the immobilization process, unlike the in situ formation of polymeric coatings or matrices around the particles Conventionally solid, the microspheres of the present invention are characterized by substantially more uniform particle sizes and less agglomeration between the microspheres. Also, the immobilization process of the present invention allows the entrapment of solid particles in microspheres of a size many times greater than that of the solid particles themselves (eg 10X, 20X, 50X, or 100X) in a period of time relatively short, while the process of matrix formation or conventional in situ coating is time consuming and only serves to form microspheres of limited sizes.

Although it can be applied to any cosmetic or topical ingredient or component in a solid or particulate form, it is believed that the present invention is particularly useful for stabilizing solid particles capable of generating oxygen free radicals without adversely affecting the desirable properties of said particles. , while eliminating any possible interaction between solid particles that generate oxygen free radicals and the other cosmetic or topical ingredients of the formulations susceptible to decomposition or oxidative degradation. For example, it is known that solid particles formed of certain metal oxides, such as zinc oxide and titanium dioxide, have photoprotective characteristics and can therefore be used as physical sunscreen agents. However, it is known that said metal oxide particles in their "bare" or untreated state release oxygen free radicals upon exposure to UV light. Such free oxygen radicals are strong oxidizers that can cause oxidative degradation of other cosmetic or topical components in the surrounding environment, such as for example organic dyes or organic sunscreen agents that are normally susceptible to oxidative decomposition or degradation. It has been shown that entrapment of said metal oxide particles that generate oxygen free radicals in the microspheres of the present invention is effective in eliminating or reducing the formation or release of oxygen free radicals from said particles when exposed to UV, without adversely affecting the sunscreen properties of said metal oxide particles. Consequently, metal oxide particles trapped in the microsphere of the present invention can be used without problem with organic compounds which, as is known, are susceptible to oxidative decomposition or degradation to form topical or cosmetic compositions with significantly improved overall stability. and a period of prolonged expiration.

Solid particles trapped in the microsphere of the present invention can be added directly to any pharmaceutically or cosmetically acceptable vehicle to form a cosmetic or topical composition. For the purposes of the present invention, pharmaceutically or cosmetically acceptable vehicles are substances that are biologically compatible with human skin and that can be used to formulate the active ingredients described above and / or then in a cream, a gel, an emulsion, a liquid, a suspension, a powder, a coating of ones, a skin oil or a lotion, which can be applied topically. In the case where the cosmetically acceptable vehicle is in the form of an emulsion, it may contain from about 0.1 to 99%, preferably from about 0.5 to 95%, more preferably from about 1 to 80% by weight of the composition total water and about 0.1 to 99%, preferably about 0.1 to 80%, more preferably about 0.5 to 75% by weight of the total oil composition. In the case where the composition is anhydrous, it may comprise from about 0.1 to 90% by weight of oil and from about 0.1 to 75% by weight of other ingredients, such as pigments, powders, non-aqueous solvents

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(such as mono-, di- and polyhydric alcohols, etc.). In the case where the composition is in the form of an aqueous-based gel, a solution or a solution, it may comprise from about 0.1 to 99% by weight of water and from about 0.1 to 75% by weight of other ingredients, such as botanical ingredients, non-aqueous solvents, etc.

Suitable components of the acceptable pharmaceutical or cosmetic vehicle include, but are not limited to: wetting agents, astringent agents, chelating agents, sequestering agents,

emulsifiers / surfactants, emollients, preservatives, stabilizers, abrasives, adsorbents, thickeners, gelling agents, solidifying / structuring agents, anti-caking agents, anti-foaming agents, buffer / pH adjustment agents, binders, film-forming agents, wetting agents, pigments, opacifiers, essential oils, fragrances and aromatic compounds. The pharmaceutically or cosmetically acceptable velmculo or velmculos may be present in the topical or cosmetic composition of the present invention in an amount within the range of about 1% to about 99.9%, preferably from about 50% to about 99.5%, more preferably from about 70% to about 99%, with the most preferred being about 80% to 90% of the total weight of the topical or cosmetic composition.

The topical or cosmetic composition may contain one or more skin care additives, which are agents that provide benefits to the skin, rather than simply improving the physical or aesthetic characteristics of the topical composition. If present, said skin care additives may be in the range of about 0.01 to 50%, preferably about 0.05 to 35% by weight of the total composition. Examples of skin care additives that can be used in the cosmetic compositions of the present invention include, but are not limited to: filter agents, self-tanning agents, anti-aging agents, anti-wrinkle agents, agents anti-acne (eg resorcinol, salidic acid and the like), enzyme inhibiting agents, collagen stimulating agents, agents for eradicating aging spots and keratosis, analgesics, anesthetics, antimicrobials (eg antibacterials, agents anti-yeasts, antifungal agents and antiviral agents), anti-dandruff agents, anti-dermatitis agents, antiprotic agents, anti-emetics, anti-inflammatory agents, anti-hyperkeratolytic agents, anti-perspirants, antipsoriasis agents, anti-seborrheic agents, antihistamic agents, agents skin lighteners, depigmenting agents, soothing / healing agents (eg, aloe vera extract, alantoma and the like), corticosteroids theoids, hormones, antioxidants, protectants or peptides, vitamins and derivatives thereof (e.g. vitamin A, vitamin E, vitamin B3, vitamin B5, and the like), scrubs, retinoids (eg, retinoic acid and retinol) farnesol, bisabolol, phytantriol, glycerin, urea, guanidine (eg, amino guanidine) , clotrimazole, ketoconazole, miconozole, griseofulvin, hydroxyzine, diphenhydramine, pramoxine, lidocama, procama, mepivacama, monobenzone, erythromycin, tetracycline, clindamycin, meclocillin, minocycline, hydroquinone, naproxenine, ibuprofen, topyl steroids eg, hydrocortisone, hydrocortisone acetate-21, hydrocortisone valerate-17 and hydrocortisone butyrate-17), betamethasone valerate, betamethasone dipropionate, benzoflo peroxide, crotamitone, propranolol, promethazin and mixtures or derivatives thereof. In a preferred, but not necessary, embodiment of the present invention, the topical composition comprises one or more active skin care principles selected from the group consisting of sunscreen agents, self tanning agents, anti-aging agents, agents anti-wrinkles, anti-acne agents, antimicrobials, anti-inflammatory agents, skin lightening agents, antioxidants, proteins or peptides, vitamins and derivatives thereof, scrubs and mixtures thereof.

For example, the topical or cosmetic compositions of the present invention may include one or more antioxidants, and more preferably one or more water-soluble extracts of biological materials that have an antioxidant action. If present, said antioxidants or water-soluble extracts with antioxidant action may be in a range between about 0.01 and 45%, preferably between about 0.05 and 20%, more preferably between about 0.1 and 15% by weight of the Total composition. Examples of water-soluble extracts that have a suitable antioxidant action include, but not limited to, extracts of: artemia, phytosphingosine, poligonum cuspidatum root, yeast as saccharomyces lysate, thermophillus thermos ferment, birch (Betula alba), extract (bark) of mimosa tenuiflora, fruit, clove, rye, malt, corn, spelled, millet, barley, oats, wheat, sesame, cumin, curcuma, green onion, celery, ginseng, ginger, licorice, carrot, bupleurum root , Ginkgo biloba (gingko), Foeniculi Fructus (fennel), kiwi, berries such as Morus bombycis (blackberry), Gentiana lutea (gentian), algae such as red algae, Arctium lappa (burdock), Salvia officinalis (sage), Lentinus edodes (mushroom shiitake), Perilla frutescens (perilla), Filipendula Multijuga, Fucus vesiculosis (Fucus, seaweed), peach bone, Allium sativum (garlic), Poria coconuts (poria), Humulus lupulus (hops), Mutan Cortex (bark of the rafz of peoma), Pimpinella major, Lactuc a sative (lettuce), Astragalus membraneceous (astragalus) and Rosmarinus officinalis (rosemary), Prunus amygdalus (almond), Althea officinale (marshmallow), aloe, Rosae Fructus (vagrant rose or Rosa multiflora), Scuttelaria baicalensis (Huange qin) Radix (Pueraria lobata rafz), chamomiles such as Chamomillae Flos (German chamomile), Gardenia jasminoides (zhii zi, Gardeniae Fructus), Sophora flavescens Aiton (Sophorae Radix), chlorella, rice bran, Paeoniae lactiflora (white peoma), ziyu ( Sanguisorba officinalis, pimpinela mayor), Morus alba (sang bai pi, blackberry), Glicine max (soy), Camellia sinensis (te), Cartami Flos (cartamo), Aesculus hippocastanum (horse chestnut), Melissa officinalis (melissa) and Coicis Semen (tear seed of Job var. ma-yuen), Angelica keisukei, Arnica montana (arnica), Foeniculum officinale (fennel), Isodon japonicus Hara (Herb Isodonis), Daucus Carota (carrot), Oryza sativa (rice), Crataegus cuneata (sea buckthorn), Acorus calamus ( aromatic squid),

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Crataegus oxicanta (hawthorn), Juniperus communis, Ligusticum wallichii (Chinese Llanten), Swertiae Herba (Chirata), Tilmus vulgaris (thyme), Citrus reticulata (tangerine), Capsicum tincture, Angelicae sinensis (angelica), Aurantii Pericarpium (orange peel ), Ruscus aculeatus (rusco), Vitis vinifera (grapes), Tilia japonica (lime), Citrus junos and Rosa canina (wild rose), coffee, Cinnamomi Cortex (cinnamon bark) and Eriobotrya japonica Lindl. (more Japanese), Gambir, Echinacea, Fellodendri Cortex (bark of wild philodendron or philodendron amurense), Hypericum perforatum (St. John's wort), Citrus sinensis (orange), Valeriana fauriei Briquet, Artemisia capillaris Thunb., Cucumis sativus (cucumber) , Geranii Herba (Geranium ivy), Litospermum erythrorhizon Red Rafz., Hedera helix, Achillea millefolium (aquilea), Ziziphus jujuba (azofeifa), Calendula officinalis (golden button), Houttuynia cordata (Houttuyniae Houttuniania Pout, heart leaves) erecta, Petroselinum crispum (parsley), Parietaria officinalis, Santalum album (sandalwood), Prunus persica (peach), Centaurea cyanus (cornflower), Eucaliptus globulus (eucalyptus) and Lavandula angustifolia (lavender), Persea americana (avocado), Nasturtium officinal (Nasturtium officinal) watercress), Symphitum officinale (consumleda), Asarum sieboldii (wild ginger), Xantoxium piperitum (Japanese pepper), Rehmannia glutinosa (Rehmannia), Peppermint (peppermint mint), Syzygium aromaticum ( clove), Tussilago farfara (tusflago) and Haematoxilum campechianum (dye stick); Oolong te, Cinchona succirubra (red quina), Betula verrucosa (common birch) and Glechoma hederacea (land ivy), milk and royal jelly, honey, cystem and its derivatives, ascorbic acid and its derivatives, hydroxybutylanisol, butylhydroxytoluene, ferulic acid and its derivatives, grape seed extract, pine bark extract, horseradish extract, hydroquinones, rosmarnic acid, robust coffee seed, caffeic acid, tocopherol and its derivatives, green tea extract, sodium DNA, sodium ribonucleic acid, gallates of octyl, propyl and dodecyl, uric acid and thiodiproprionate derivatives.

In one embodiment of the present invention, but not necessary, one or more of the antioxidant agents, such as those listed, are co-immobilized in the microspheres, together with the particulate components of the present invention. Said co-immobilization can be carried out for example by mixing said antioxidant agents with the particulate components, the hollow microspheres and the polar organic solvent during the gelation step to form a gelled mixture. Particularly preferred antioxidant agents for co-immobilization with the particulate components of the present invention include for example tetrahydrocurcuminoids, ascorbyl tocophenyl maleate (also called 2-CME), grape seed extract and rosemary extract. Most preferred is a mixture or combination containing all these particularly preferred antioxidant agents in equal or substantially equal amounts for the practice of the present invention. Such co-trapped antioxidant agents can sweep or deplete in a very effective manner the oxygen free radicals generated by the trapped metal oxide particles due to their direct contact therein and spatial proximity.

Antioxidant agents, as listed above, can also be used to form an antioxidant coating on the microspheres that will better or neutralize oxygen free radicals released from them. Also, antioxidant agents may be provided in a solubilized or dispersed form in the cosmetic or pharmaceutically acceptable carrier of the topical or cosmetic composition of the present invention. Said solubilized or dispersed antioxidant agents serve to sweep or neutralize the oxygen free radicals dispersed in the topical or cosmetic compositions, regardless of the origin of said free oxygen radicals, thereby further improving the overall stability of the compositions. topics or cosmetics of the present invention.

In a particularly preferred embodiment of the present invention, the topical or cosmetic composition is a sunscreen composition comprising zinc oxide particles trapped in the microsphere, or titanium dioxide particles trapped in the microsphere, or both. As mentioned above, zinc oxide or titanium dioxide particles are known for their photoprotective characteristics and therefore, they can be used as physical sunscreen agents, although their uses in topical or cosmetic compositions are limited due to to its photo-activity, that is, its tendency to release free oxygen radicals after exposure to UV light, which can degrade or otherwise interfere with certain organic cosmetic ingredients or active skin care principles that are susceptible to decomposition or oxidative degradation. The entrapment of zinc oxide and / or titanium dioxide particles in the microspheres, as described in the present invention, effectively eliminates or reduces free oxygen radicals from said particles after UV exposure, but without adversely affecting the sunscreen properties of said particles.

Accordingly, particles of zinc oxide and / or titanium dioxide trapped in the microsphere of the present invention can be easily formulated with organic cosmetic ingredients or skin care additives that are known for their susceptibility to oxidative decomposition or degradation to form stable sunscreen compositions with significantly improved overall stability and a prolonged expiration period. For example, particles of zinc oxide and / or titanium dioxide trapped in the microsphere of the present invention can be formulated with one or more organic dyes susceptible to decomposition or oxidative degradation to form color cosmetic compositions that also have filter properties. solar. Also as an example, the particles of zinc oxide and / or titanium dioxide trapped in the microsphere of the present invention can be formulated with one or more organic sunscreen agents susceptible to oxidative decomposition or degradation, thereby forming compositions of sunscreen that is not only characterized by high SPF values (eg SPF 30 or more), but also, surprisingly and unexpectedly, improves overall stability and has a prolonged expiration period. If present, said sunscreen agents

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Organic may be in the range of about 0.1 to 45% by weight of the total composition.

Examples of organic sunscreen agents that can be used in combination with the particles of zinc oxide or titanium dioxide trapped in the microsphere of the present invention include, but are not limited to, UVA and UVB sunscreens, such as benzophenones and derivatives thereof (eg, benzophenone-3, dioxibenzone, sulisobenzone, octabenzone, hydroxy- and / or methoxy-substituted benzophenones and benzophenonasulfonic acids and salts thereof); derivatives of salidic acid (eg ethylene glycol salicylate, triethanolamine salicylate, octyl salicylate, homomethyl salicylate and phenyl salicylate); urocanic acid and derivatives thereof (eg ethyl urocanate); p-aminobenzoic acid (PABA) and derivatives thereof (eg ethyl / isobutyl / glycolic esters thereof and 2-ethylhexyl p-dimethylaminobenzoate, which is also called octyldimethyl PABA); anthranilates and derivatives thereof (eg o-amino-benzoates and various esters of aminobenzoic acid); benzalmalonate derivatives; benzimidazole derivatives; imidazolines; ibis-benzazolyl derivatives; dibenzoylmethanes and derivatives thereof (eg 4-tert-butyl-4'-methoxy dibenzoylmethane, which is usually referred to as "avobenzone" and 4-isopropyl dibenzoflmethane); benzoazol / benzodiazol / benzotriazoles and derivatives thereof (eg 2- (2-hydroxy-5-methylphenyl) benzotriazol and methylene bis-benzotriazolyl tetramethylbutylphenol, which is usually referred to as "Tinosorb M"; diphenylacrylates and derivatives thereof ( eg 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, which is usually referred to as "ethyl octocrylene" and ethyl 2-cyano-3,3-diphenylacrylate, which is usually referred to as "ethocrylene"); diesters or polyesters containing diphenylmethylene or 9H-fluorene substitution groups; 2-phenyl-benzimidazol-5-sulfonic acid (PBSA); 4,4-diarylbutadienes; cinnamates and derivatives thereof (eg 2-ethylhexyl-p-methoxycinnamate, octyl-p-methoxycinnamate, umbelliferone, methylumbelliferone, methylacetoumbeliferone, esculetin, methylstyletine and daphnetin); camphor and derivatives thereof (eg 3-benzylidene camphor, 4- methylbenzylidene camphor, polyacrylamidomethyl benzylidene camphor, benzyl acid acycide and sulfon tereftaliden dialcanfor sulfonic, which is usually called "Encamsule"); triazines and derivatives thereof (eg 2,4-bis - {[4- (2-ethyl-hexyloxy) -2-hydroxy] -phenyl} -6- (4-methoxyphenyl) -1,3,5 -triazin, which is usually called "Tinosorb S"); naphthalates and derivatives thereof (eg 2,6-diethylhexyl naphthalate; naphthosulfonates and derivatives thereof (eg sodium salts of 2-naphthol-3,6-disulfonic and 2-naphthol-6 acids , 8-disulfonic); dibenzalacetone and benzalacetonephenone; diphenylbutadienes and derivatives thereof; di-hydroxynaphthoic acid and salts thereof; o- and p-hydroxybiphenyldisulfonates; coumarin derivatives (e.g., 7-hydroxy, 7-methyl derivatives , and 3-phenyl thereof); azoles / diazoles / triazoles and derivatives thereof (e.g., 2-acetyl-3-bromoindazole, phenyl benzoxazole, methyl naphthoxazole, and various aryl benzotriazoles); quinine and derivatives of the same (e.g., bisulfate, sulfate, chloride, oleate and tanate salts thereof); quinoline and derivatives thereof (e.g., 2-phenylquinoline and 8-hydroxyquinoline salts); tanic acid and derivatives thereof (eg, derivatives of hexaethyl ether thereof); hydroquinone and derivatives thereof; uric acid and derivatives thereof; vilouric acid and derivatives thereof and mixtures or combinations of them. Also useful in the present invention are salts and otherwise neutralized forms of certain acidic sunscreens from the list listed above. These organic sunscreen agents can be used alone or by combining two or more of them. In addition, it is possible to use other animal or vegetable extracts that have the ability to absorb UV light alone or in combination.

The organic sunscreen agents that are particularly useful in the practice of the present invention are: 4,4'-t-butyl methoxydibenzoylmethane, 2-cyano-3,3-diphenylacrylate of 2-ethylhexyl, 2-ethylhexyl salicylate, salicylate of 3,3,5-trimethylcyclohexyl, 2-ethylhexyl p-methoxycinnamate, 2-hydroxy-4-methoxybenzophenone, 2,2-dihydroxy-4- methoxybenzophenone, 2,4-bis- {4- (2-ethyl-hexyloxy) ) -2-hydroxy] -phenyl} -6- (4-methoxyphenyl) -1,3,5-triazine, methylene bis-benzotriazolyl tetramethylbutylphenol, terephthalylide dialkane sulfonic acid, 2,6-diethylhexyl naphthalate, digaloyltrioleate, 4- [ ethyl bis (hydroxypropyl)] aminobenzoate, glycerol p-aminobenzoate, methylantranilate, p-dimethylaminobenzoic acid or aminobenzoate, 2-ethylhexyl p-dimethylaminobenzoate, 2-phenylbenzimidazole-5-sulfonic acid, 2- (p-dimethyl) 5-sulfonium benzoxazoic acid, and mixtures and combinations thereof. Preferably, 4,4'-t-butyl methoxy dibenzoylmethane is provided in the sunscreen compositions of the present invention, either with titanium dioxide trapped in the microspheres or with titanium oxide trapped in the microspheres, or both. More preferably, the sunscreen compositions of the present invention may further include a second organic sunscreen agent selected from the list set forth above.

The organic sunscreen agents described above can be freely solubilized or dispersed in the cosmetic or pharmaceutically acceptable vehicle of the topical or cosmetic compositions of the present application. Alternatively, organic sunscreen agents can be provided in a protected form, that is, encapsulated in protective structures. For example, organic sunscreen agents can be encapsulated or trapped in additional microspheres similar to those described, that is, with collapsed polymeric envelopes. In this way, organic sunscreen agents are better protected against oxygen free radicals and other radicals in the surrounding environment that can destabilize or degrade said organic filter agents.

The cosmetically acceptable vehicle may also contain one or more oils, which may consist of organic silicone, or mixtures thereof. If present, said oils may be in the range of about 0.1 to 99% by weight of the total composition, and among them volatile and non-volatile silicones such as cyclomethicone are included; methyl trimethicone; octamethyltrisiloxane; decamethyltetrasiloxane; dodecamethylpentasiloxane; dimethicone; phenyl trimethicone trimethylsiloxyphenyl dimethicone; phenyl dimethicone; cetil

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dimethicone; dimethicone copolyol, cetyl dimethicone copolyol; Glycerylated silicones such as lauryl PEG-9 polydimethylsiloxyeti dimethicone; or mixtures thereof. Suitable esters include mono-, di-, or triesters of C4-30 fatty acids and C1-20 mono-, di- or polyhydric alcohols, such as fatty acid esters (eg, steanolic, behemolic, and isostanolic) ) of glycerin, or fatty acid esters of alpha hydroxylic acids such as citric, malic or lactic acids and the like. Suitable hydrocarbons include monomeric or polymeric olefins or alpha olefins, such as polyisobutene, polydecene, polybutene or hydrogenated derivatives thereof.

The cosmetically acceptable vehicle may also comprise one or more humectants. If present, they may be in the range of about 0.1 to 20% by weight of the total composition and include alkylene C1-4 glycols such as butylene, propylene, ethylene glycol, glycerin and the like.

The cosmetically acceptable carrier may also contain one or more waxes, preferably with a melting point between about 30 and 150 ° C. If present, said waxes are in the range between about 0.1 and 45% by weight of the total composition and among them animal, vegetable, mineral or silicone waxes are included. Examples include alkyl dimethicones, stearyl dimethicone, candelilla, polyethylene, ozoquerite, beeswax and the like.

The cosmetically acceptable carrier may comprise one or more organosiloxane elastomers, emulsifiers or non-emulsifiers. If present, said elastomers are in the range of about 0.1 to 30% by weight of the total composition. Examples of suitable elastomers include cross-linked dimethicone / vinyl dimethicone polymer; crosslinked dimethicone / PEG / PPG polymer 10/15 dimethicone; and the like

The cosmetically acceptable vehicle may also contain one or more pigments or powders or mixtures thereof. If present, the suggested ranges for said pigments or powders are between about 0.1 and 85% by weight of the total composition. The particle sizes of said pigments or powders may be in the range between about 0.05 and 200 micrometers but preferably between about 50 and 100 micrometers. Examples of such pigments include organic pigments such as D&C or FD&C colors or coloring lacquers thereof, including blues, browns, reds, etc., or inorganic iron oxides, such as brown iron oxides, yellow, green, red Suitable powders include titanium dioxide, nylon, PMMA, boron nitride, mica and the like.

The cosmetically acceptable carrier may also comprise one or more non-ionic surfactants, in particular if the topical or cosmetic composition of the present invention in the form of an emulsion is provided. If present, said surfactants are in the range between about 0.1 and 20% by weight of the total composition. Suitable surfactants include ethoxylated C6-30 fatty alcohols such as stearet, beheneth, ceteh, in which the number that follows each of the surfactants refers to the number of repeating ethylene oxide groups, which may range between 2 and 250, eg estearet-2, beneth-30, and so on.

The present invention can be better illustrated with the following non-exhaustive examples.

Example I

It is placed in an Expancel 551 DE 20 d 60 mixing chamber (DE 20 indicates the average particle size of 20 micrometers) - approximately 800 g. Acetone is added in an amount of approximately 4,000 ml at 20 rpm. A gel is formed and approximately 343 g of ultrafine titanium dioxide (D 50 2 micrometers) are added to the gel. It is combined until a homogeneous mixture of titanium dioxide and the gel is obtained. The acetone is removed by heating the combination in a vacuum chamber. The titanium dioxide particles in the microspheres are immobilized and the outer layer of the microspheres is coated with approximately 14 percent by weight of a Dow Corning 1107 silicone polymer. The final particle size of the microspheres is measured. they immobilize TiO2 with a Malvern particle size analyzer, available from Malvern Instrument Scirocco 2000 in Worcestershire, UK, the result being between 5 and 8 micrometers.

Example II

Following the process outlined in Example I using Expancel 461 DE 40 d 60 the same result was obtained, the final particle size of the microspheres that immobilize TiO2 ranges between 5 and 8 micrometers.

Example III

Example I was repeated with irregular solid particles of Dow Chemical Saran F 310 (Vinylidene Polychloride). This experiment was carried out to test the ability of the particles to disperse in the gelled polymer, regardless of their original form or composition.

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Example IV

Expancel 551 DE 20 d 60 is placed, approximately 300 g in a mixing chamber. Acetone is added in an amount of approximately 2,550 ml at 20 rpm. A gel is formed and approximately 463 g of ultrafine zinc dioxide (D 50 2 micrometers) are added to the gel. It is combined until a homogeneous mixture of zinc dioxide and gel is obtained. The acetone is removed by heating the combination in a ford chamber. The zinc oxide particles in the microspheres are immobilized and the outer layer of the microsphere is coated with approximately 10 weight percent of a Dow Corning 7-4404 cosmetic fluid. The final particle size of microspheres that immobilize ZnO is measured using a Malvern particle size analyzer from Malvern Instrument in Worcestershire, UK, the result being between 5 and 8 micrometers.

Example V

A comparative test was carried out to determine the photodegradation of an organic dye, specifically D&C red No. 28 (or Red 28), with UV exposure and in the presence of several TiO2 particles, both without encapsulating (i.e., naked) ) as trapped with and without antioxidant in the microspheres of the present invention, as described above.

Specifically, an ethanol solution containing 0.013% weight of Red 28 was provided as a control sample. Next, several comparative samples were prepared containing respectively: (1) 0.011% weight of Red 28 and 0.02% weight of uncapsulated or naked TO2 particles of an average particle size of approximately 20-50 nm dispersed in ethanol ; (2) 0.011% weight of Red 28 and 0.04% weight of TiO2 immobilization microspheres with co-trapped antioxidants (containing titanium dioxide, aluminum hydroxide / stearic acid, copolymer of vinylidene / acrylonitrile polychloride, methicone and tetrahydrocurcuminoids) dispersed in ethanol; and (3) 0.011% weight of Red 28 and 0.04% weight of TO2 immobilization microspheres without any antioxidant (containing titanium dioxide, aluminum hydroxide / stearic acid, copolymer of vinylidene / acrylonitrile polychloride and methicone), dispersed in ethanol.

The light transmission at a wavelength of approximately 400-700 nm of the control sample and the comparative samples were measured before UV exposure with a Spectroflash SF600 Plus-CT colonometer commercially available from DataColor in Lawrenceville, NJ. The control sample and comparative samples were exposed to UV light of approximately 275J. After the UV exposure, the light transmission at 400-700 nm of the control sample and the comparative samples was measured again and compared with the light transmission values before the UV exposure, and were calculated based on those measures the DE color changes of approximately 7.34 for the control sample, 9.32 for the TO2 immobilization microspheres without any antioxidant, 3.89 for the TO2 immobilization microspheres with co-trapped antioxidants and 82.77 for particles of TO2 without encapsulating or naked.

FIG. 3 is a graph showing the percentage of color changes of several samples described above, including (from left to right): the control sample, the comparative sample (1) the comparative sample (2 ) and the comparative sample (3). In view of FIG. 3 it is evident that when TO2 particles were encapsulated without encapsulating or naked, a large part of the Red dye 28 degraded with UV exposure, and instead the entrapment of the TO2 particles in the microspheres of the present invention, both with oxidants as without them, it effectively reduced the degradation of said organic dye to a level that was comparable to that of the control sample or less with respect to the control sample.

Example VI

A comparative test was carried out to determine the absorbance spectra of uncapsulated (or naked) TiO2 particles and the particles of TO2 trapped in microspheres of the present invention.

The two formulas (I and II) set forth below were prepared, one of which contains naked TO2 particles and the other, the TO2 particles trapped in the microsphere of the present invention:

 Components

 % by weight in Formula I (with bare TiO2)% by weight in Formula II (with trapped TiO2)

 Deionized water

 35.07 30.59

 Naked TO2 (titanium dioxide / aluminum hydroxide / stearic acid in trioctyldodecyl citrate)

 17.40 "

 TO2 trapped in microsphere (titanium dioxide, aluminum hydroxide / stearic acid, copolymer of vinylidene / acrylonitrile polychloride, and methicone)

   13.00

 Butylene Glycol

 8.00 8.00

 Components

 % by weight in Formula I (with bare TiO2)% by weight in Formula II (with trapped TiO2)

 Cyclopentasiloxane

 7.00 6.00

 Isopropyl titanium triisoestearate / C12-C15 / 6-polyglyceryl polyhydric oleate / zinc oxide / caprilyl methicone

 6.00 6.00

 Tricapriline

 3.42 3.00

 Trioctyldodecyl citrate

 2.75 11.52

 Estearet-2

 2.42 2.42

 Tricaprilyl citrate

 2.00 2.50

 Silica

 2.00 2.00

 Dipentaerythrityl tri-polyhydroxystearate

 2.00 2.00

 Stearyl Dimethicone

 1.93 1.93

 Lecithin

 1.00 1.00

 Calcium sulfate

 1.00 1.00

 Titanium dioxide / methicone

 1.00 1.00

 Barium sulfate

 1.00 1.00

 Sorbitan Triestearate

 0.77 0.77

 Magnesium aluminum silicate

 0.60 0.60

 Silver borosilicate

 0.50 0.50

 Dimethicone

 0.50 0.50

 PEG-40 Stearate

 0.41 0.41

 Ceteth-2

 0.41 0.41

 PEG / PPG-18/18 dimethicone

 0.40 1.50

 Xanthan gum

 0.40 0.40

 Iron oxide yellow

 0.40 0.33

 Phosphoric acid

 0.30 0.30

 Tocopheryl acetate (Vitamin E)

 0.25 0.25

 Ascorbil magnesium phosphate

 0.25 0.25

 Estearet-20

 0.22 0.22

 Disodium EDTA

 0.20 0.20

 Panthetin

 0.10 0.10

 Sodium stearate

 0.10 0.10

 B HT

 0.10 0.10

 Bisabolol

 0.05 0.05

 Iron oxide red

 0.02 0.02

 Iron oxide black

 0.02 0.02

The two described formulas were exposed to approximately 225 J UV rays emitted by a Thermo Oriel solar simulator - manufactured by Newport Corporation in Stanford, CT. The photo-absorbance of the two formulas 5 was measured during Uv exposure with a Radiometer / Photometer manufactured by Light Technologies in Peabody, MA and the graph of FIG. 4. In view of FIG. 4, it is evident that in comparison with the uncapsulated or naked TO particles, the TiO2 particles trapped in microspheres exhibited comparable absorbance

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in the UVB interval (at a wavelength of approximately 280-315 nm) and a significantly higher absorbance in the UVA range (at a wavelength of approximately 315 nm-400 nm).

Example VII

A comparative test was carried out to determine the photostability of 4,4'-t-butyl methoxy dibenzoylmethane (Avobenzone) in the presence of bare or encapsulated TiO2 particles and TiO2 particles trapped in microspheres of the present invention.

The following two formulas (III and IV) were prepared, one of which contains uncapsulated or naked TO2 particles and the other, the TO2 particles trapped in microspheres of the present invention:

 Components

 % weight in Formula III (with bare TiO2)% weight in Formula IV (with trapped TiO2)

 Deionized water

 51.50 44.90

 TiO2 coated (titanium dioxide / aluminum hydroxide / stearic acid in trioctyldodecyl citrate)

 17.40

 TiO2 trapped in microsphere (copolymer of vinylidene / acrylonitrile polychloride, titanium dioxide, stearic acid, aluminum hydroxide and methicone)

   13.00

 Neopentyl glycol diheptanoate

 9.50 9.50

 Butylene Glycol

 4.00 4.00

 Cetearyl Olive / Sorbitan Olive

 4.00 4.00

 Kukui nut oil

 3.00 3.00

 Avobenzone

 3.00 3.00

 Lauryl PEG-9 polydimethylsiloxyethyl dimethicone

 3.00 3.00

 Hydrogenated olive oil / olive oil / unsaponifiable olive oil

 2.00 2.00

 Dimethicone

 1.00 1.00

 Cetyl alcohol

 0.75 0.75

 Silver borosilicate

 0.50 0.50

 Xanthan gum

 0.25 0.25

 Disodium EDTA

 0.10 0.10

 Trioctildecil citrate

 - 11.00

The two described formulas were exposed to UV light at various intensities, namely 50 J, 90 J, and 275 J, emitted by a Thermo Oriel-Solar solar simulator manufactured by Newport Corporation in Stratford, CT. The photoabsorbance of these two formulas was measured before and after UV exposure with a Radiometer / Photometer manufactured by International Light Technologies in Peabody, MA 01960. The initial photoabsorbance of said formulas was recorded before the UV exposure as the baseline values. FIG. 5 shows the photoabsorbance curves of Formula III in the initial state (that is, before UV exposure) and after exposure to UV light at 50J, 90J, and 275J. In FIG. 5B the photo-absorbance curves of Formula IV are shown in the initial state (i.e., before UV exposure) and after exposure to UV light at 50J, 90J, and 275J.

It is evident that when combined with naked TiO2 particles, avobenzone is significantly less photostable than when combined with the TiO2 particles trapped in microspheres of the present invention, as evidenced by the significantly greater reduction of the photoabsorbance of Formula III in comparison with that of Formula IV after exposure to UV light at a higher intensity (eg, 275J), as shown in FIGS. 5A and 5B.

Example VIII

Below are several examples of topical or cosmetic sunscreen formulas containing TO2 particles trapped in microspheres or ZnO particles trapped in microspheres of the present.

invention.

Sunscreen Formula 1

This facial lotion is an oil-in-water emulsion containing TO2 particles trapped in the microsphere of the present invention (without any co-trapped antioxidant) in combination with various organic sunscreen agents, including Avobenzone:

 Components

 % weight

 Deionized water

 35.08

 Disodium EDTA

 0.10

 Sodium Dihydroacetate

 0.10

 Acetyl Glucosamine

 0.05

 Cafema

 0.20

 Butylene Glycol

 2.00

 Xanthan gum dehydro

 0.25

 Avobenzone

 3.00

 Ethylhexyl salicylate

 5.00

 Benzophenone-3

 5.00

 Polyester-8

 3.00

 Butyloctyl Salicylate

 4.00

 Copolfmero maleate isopropyl / olefin C30-C38 / MA

 0.75

 CopoKmero VP / eicoseno

 0.75

 Potassium Cetyl Phosphate

 1.00

 PEG-100 Stearate

 2.25

 Glyceryl stearate

 1.50

 Cetyl alcohol

 0.75

 Stearic acid

 0.75

 Homosalate

 5.00

 Kukui nut oil

 3.00

 Dipentaerythrityl tri-polyhydroxystearate

 1.50

 Curcuma root extract

 0.01

 TO2 trapped in microsphere (titanium dioxide, aluminum hydroxide / stearic acid, copolymer of vinylidene / acrylonitrile polychloride and methicone)

 6.00

 Mica

 5.00

 Lauryl PEG-9 polydimethylsiloxyethyl dimethicone

 2.00

 Methyl trimethicone

 5.00

 Methicone caprylil

 1.50

 Ethylhexyl glycerin

 0.50

 Phenoxyethanol / caprylic glycol / sorbic acid

 0.85

 Copolymer of ammonium acryodimethyl restaurant / VP

 0.20

 Mulberry root extract / scutellaria baicalensis extract / grape extract

 0.10

 Yeast extract

 0.01

 Whey protein

 0.01

 Fragrance

 0.20

Sunscreen Formula 2

This facial lotion is an oil-in-water emulsion containing the particles of ZnO entrapped in microsphere of the present invention (without any co-trapped antioxidant) in combination with various organic sunscreen agents, including Avobenzone:

 Components

 % weight

 Deionized water

 30.86

 Disodium EDTA

 0.10

 Dipentaerythrityl tri-polyhydroxystearate

 2.00

 Butylene Glycol

 4.00

 Xanthan gum

 0.20

 Acrylic acid / VP crosslinked polymer

 0.25

 Avobenzone

 3.00

 Ethylhexyl salicylate

 5.00

 Mica

 5.00

 Polyester-8

 3.00

 Butyloctyl Salicylate

 3.50

 Neopentyl glycol diheptanoate

 2.50

 Isopropyl / olefin maleate copolymer C30-C38 / MA

 0.80

 Octocrylene

 2.79

 Cetyl alcohol

 0.75

 CopoKmero VP / eicoseno

 0.50

 Potassium Cetyl Phosphate

 1.00

 PEG-100 Stearate

 2.25

 Glyceryl stearate

 1.50

 Homosalate

 5.00

 Kukui nut oil

 6.00

 Benzophenone-3

 5.00

 Copolymer styrene / acrylates // PEG-8 laurate // water

 1.00

 ZnO trapped in microsphere (zinc oxide, isopropyl titanium, triisoestearate, copolymer of vinylidene / acrylonitrile polychloride and methicone)

 6.00

 Lauryl PEG-9 polydimethylsiloxyethyl dimethicone

 2.00

 Methyl trimethicone

 3.00

 Caprilil methicone

 1.50

 Ethylhexyl glycerin

 0.50

 Phenoxyethanol / caprylic glycol / sorbic acid

 0.85

 Trimetamine

 0.15

Sunscreen Formula 3

This facial lotion is a silicone water emulsion containing the TiO2 particles trapped in the microsphere of the present invention (without any co-trapped antioxidant:

 Components

 % weight

 Deionized water

 41.68

 Dipentaerythrityl tri-polyhydroxystearate

 2.00

 Butylene Glycol

 6.00

 Xanthan gum

 0.25

 Glycerin

 2.00

 Phenoxyethanol / Caprylic Glycol

 0.85

 Phenoxyethanol

 0.20

 Magnesium sulphate

 1.00

 Cetil PEG / PPG-10/1 dimethicone

 1.00

 Titanium dioxide / methicone

 4.35

 TO2 trapped in microsphere (titanium dioxide, copolymer of vinylidene / acrylonitrile polychloride ^ trimethylated lice)

 8.70

 Cross-linked dimethicone polymer // PEG-10/15 dimethicone

 2.00

 Lauryl PEG-9 polydimethylsiloxyethyl dimethicone

 1.00

 Cross-linked polymer dimethicone / vinyl dimethicone // methyl trimethicone

 1.50

 Pantetilna

 0.50

 Tocopheryl acetate

 0.20

 Neopentyl glycol diethylhexanoate

 7.50

 Polydiethylsiloxane

 3.00

 Methyl trimethicone

 16.27

Sunscreen Formula 4

This facial lotion is an oil-in-water emulsion that contains the particles of TO2 trapped in the microsphere of the present invention with antioxidant co-trapped in combination with Avobenzone:

 Components

 % weight

 Deionized water

 39.15

 Disodium EDTA

 0.10

 Cafema

 0.20

 Butylene Glycol

 3.00

 Xanthan gum dehydro

 0.30

 Copolfmero VP / eicoseno

 0.75

 Potassium Cetyl Phosphate

 1.00

 PEG-100 Stearate

 2.25

 Glyceryl stearate

 1.50

 Cetyl alcohol

 0.75

 Stearic acid

 0.75

 Kukui nut oil

 6.00

 Dipentaerythrityl tri-polyhydroxystearate

 1.50

 Butyloctyl Salicylate

 4.00

 Neopentyl glycol diheptanoate

 7.00

 Components

 % weight

 Isopropyl / Olefin Maleate CopoKomer C30-C38 / MA

 0.75

 Dioctyl succinate

 10.00

 Avobenzone

 3.00

 Polyester-8

 3.00

 TiO2 trapped in microsphere with antioxidants (titanium dioxide, copolymer of polyvinylidene / acrylonitrile polychloride / triethylated silica and tetrahydrocurcuminoids)

 6.00

 Lauryl PEG-9 polydimethylsiloxyethyl dimethicone

 3.00

 Methyl trimethicone

 5.00

 Ethylhexyl glycerin

 0.30

 Phenoxyethanol / Caprylic Glycol

 0.50

 Copolymer of ammonium acryodimethyl restaurant / VP

 0.20

Sunscreen Formula 5

This facial lotion is an oil-in-water emulsion containing TO2 particles trapped in the microsphere of the present invention (without any co-trapped antioxidant) in combination with various organic sunscreen agents (without Avobenzone):

 Components

 % weight

 Deionized water

 38.08

 Disodium EDTA

 0.10

 Sodium Dihydroacetate

 0.10

 Acetyl Glucosamine

 0.05

 Cafema

 0.20

 Butylene Glycol

 2.00

 Xanthan gum dehydro

 0.25

 Ethylhexyl salicylate

 5.00

 Benzophenone-3

 5.00

 Polyester-8

 3.00

 Butyloctyl Salicylate

 4.00

 Neopentyl glycol diheptanoate

 3.50

 Isopropyl / Olefin Maleate CopoKomer C30-C38 / MA

 0.75

 Copolfmero VP / eicoseno

 0.75

 Potassium Cetyl Phosphate

 1.00

 PEG-100 Stearate

 2.25

 Glyceryl stearate

 1.50

 Cetyl alcohol

 0.75

 Stearic acid

 0.75

 Homosalate

 5.00

 Kukui nut oil

 3.00

 Dipentaerythrityl tri-polyhydroxystearate

 1.50

 Curcuma root extract

 0.01

 Components

 % weight

 TiO2 trapped in microsphere (titanium dioxide / aluminum hydroxide / stearic acid, copolymer of vinylidene / acrylonitrile polychloride and methicone)

 6.00

 Mica

 5.00

 Lauryl PEG-9 polydimethylsiloxyethyl dimethicone

 2.00

 Methyl trimethicone

 5.00

 Caprilil methicone

 1.50

 Ethylhexyl glycerin

 0.50

 Phenoxyethanol / caprylic glycol / sorbic acid

 0.85

 Ammonium / VP Acrylonimethyl Restaurant CopoKmero

 0.20

 Mulberry root extract / scutellaria baicalensis extract / grape extract

 0.10

 Yeast extract

 0.01

 Whey protein

 0.01

 Fragrance

 0.20

Sunscreen Formula 6

This facial lotion is an oil-in-water emulsion that contains the ZnO particles trapped in the microsphere of the present invention (without any co-trapped antioxidant) in combination with various organic sunscreen agents, including Avobenzone:

 Components

 % weight

 Deionized water

 33.82

 Disodium EDTA

 0.10

 Dipentaerythrityl tri-polyhydroxystearate

 2.00

 Caprilil Glycol

 0.30

 Butylene Glycol

 4.00

 Xanthan gum

 0.30

 Avobenzone

 3.00

 Ethylhexyl salicylate

 5.00

 Mica

 5.00

 Octocrylene

 2.79

 Butyloctyl Salicylate

 5.00

 Neopentyl glycol diheptanoate

 1.50

 Isopropyl / olefin maleate copolymer C30-C38 / MA

 0.80

 Copolfmero VP / eicoseno

 0.50

 Potassium Cetyl Phosphate

 1.00

 PEG-100 Stearate

 2.25

 Glyceryl stearate

 1.50

 Cetyl alcohol

 0.75

 Homosalate

 5.00

 Kukui nut oil

 5.00

 Silica

 2.00

 Copolymer styrene / acrylates // PEG-8 laurate // water

 1.00

 Components

 % weight

 Lauryl PEG-9 polydimethylsiloxyethyl dimethicone

 2.00

 Methyl trimethicone

 5.00

 Dimethicone

 1.50

 ZnO trapped in microsphere (zinc oxide / diphenyl capril methicone, copolymer of vinylidene polychloride / acrylonitrile / trimethylated silica)

 7.44

 Ethylhexyl glycerin

 0.50

 Phenoxyethanol / Caprylic Glycol

 0.85

 Triglyceride Capnlico / caprico / l aminaria ochroleuca extract

 0.10

Sunscreen Formula 7

This facial lotion is a water-in-silicone emulsion that contains the particles of TO2 trapped in microsphere of the present invention (without any co-trapped antioxidant):

 Components

 % weight

 Deionized water

 39.67

 Dipentaerythrityl tri-polyhydroxystearate

 2.00

 Butylene Glycol

 6.00

 Xanthan gum

 0.25

 Glycerin

 2.00

 Phenoxyethanol / Caprylic Glycol

 0.85

 Phenoxyethanol

 0.20

 Magnesium sulphate

 1.00

 Cetil PEG / PPG-10/1 dimethicone

 1.00

 TO2 trapped in microsphere (titanium dioxide / copolymer of vinylidene polychloride / acrylonitrile / trimethylated silica)

 17.40

 Cross-linked dimethicone polymer // PEG-10/15 dimethicone

 2.00

 Lauryl PEG-9 polydimethylsiloxyethyl dimethicone

 1.00

 Cross-linked polymer dimethicone / vinyl dimethicone // methyl trimethicone

 1.50

 Panthetin

 0.50

 Tocopheryl acetate

 0.20

 Neopentyl glycol diethylhexanoate

 7.50

 Polydiethylsiloxane

 3.00

 Methyl trimethicone

 13.92

 Sorbitan sesquioleate

 0.01

Sunscreen formula 8

This anhydrous formula, which contains the microsphere-trapped zinc oxide of the present invention in combination with various organic sunscreen agents, including Avobenzone, can be used to form a tanning product in the form of a bar.

 Components

 % weight

 Hexahydroxystearate / stearate / dipentaerythrityl rosinate

 1.50

 2-bis-diglyceryl polyacipadipate

 13.00

 Butter

 4.00

 Polyglyceryl Triisotearate-2

 6.00

 Butyloctyl Salicylate

 4.00

 Tetrabehenate / dipentaerythrityl polyhydroxystearate / behenic acid // hydroxystearic acid

 5.00

 Microcrystalline wax

 5.00

 Avobenzone

 3.00

 Ethylhexyl salicylate

 5.00

 Homosalate

 5.00

 Polyester-8

 3.00

 Tridecyl Trimelitate

 5.00

 Polyethylene

 2.50

 Isononyl Isononanoate

 1.00

 Diethylhexyl carbonate

 8.00

 Neopentyl glycol diheptanoate

 3.79

 Tricapriline

 2.75

 Mica / iron oxides / titanium dioxide

 1.50

 Mica / iron oxides

 0.75

 Microsphere trapped ZnO (zinc oxide / diphenyl capril methicone, polyvinylidene / acrylonitrile polychloride copolymer / trimethylated smero lice)

 2.00

 Tetra-di-t-butyl pentaerythrityl hydroxyhydrocinamate

 0.01

 Tocopheryl acetate

 0.10

 Simethicone

 0.10

Sunscreen Formula 9

This anhydrous formula, which contains zinc oxide trapped in the microspheres of the present invention in combination with various organic sunscreen agents including Avobenzone, can be used to form a gel-type tanning product.

 Components

 % weight

 Hydrogenated Polyisobutene

 13.00

 Simethicone

 0.10

 Copolfmero VP / Eicoseno

 7.00

 Dextrin palmitate

 11.00

 Hydrogenated Polyisobutene

 22.50

 Dimethicone

 9.00

 Tetra-di-t-butyl pentaerythrityl hydroxyhydrocinamate

 0.05

 Hydrogenated polyisobutene copolymer / ethylene / propylene / styrene / butylene copolymer / ethylene / styrene

 4.50

 Hexahydroxystearate / hexostearate / dipentaerythrityl hexarosinate

 1.08

 PPG-3 myristyl ester

 1.00

 Jojoba Butter

 1.00

 Components

 % weight

 Butyloctyl Salicylate

 4.00

 Avobenzone

 3.00

 Isopropyl / Olefin Maleate CopoKomer C30-C38 / MA

 1.00

 Tocopheryl acetate

 0.50

 Sweet almond oil

 1.00

 Calcium and sodium borosilicate / iron oxides

 0.50

 Calcium and sodium borosilicate / titanium dioxide / iron oxides

 1.50

 Mica / iron oxides

 1.50

 Ethylhexyl salicylate

 5.00

 Homosalate

 5.00

 Polyester-8

 3.00

 Esters of jojoba

 1.77

 ZnO trapped in microsphere (zinc oxide / diphenyl capril methicone, copolymer of vinylidene polychloride / acrylonitrile / trimethylated silica)

 2.00

Claims (17)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 1. A method for modifying or treating solid particles comprising: (a) form a gelled mixture by mixing, either simultaneously or successively in any order: (1) hollow microspheres that each comprise a deformable polymeric shell having an expandable fluid trapped therein, (2) a polar organic solvent capable of swelling, but not dissolving, the polymeric shells of the hollow microspheres, the acetone polar organic solvent being, and (3) solid particles, in which the polar organic solvent molecules enter between the polymer chains of the polymer shell and interrupt the intermolecular bonds between the chains, forming micro-channels in the swollen polymer envelopes to allow the entry of the solid particles into the hollow microspheres and the Expandable fluid outlet therefrom, thereby forming microspheres, each comprising a collapsed polymeric shell having an average particle size within the range of about 1 to 15 micrometers, according to a Malvern particle size analyzer, in a state gelled and having one or more of said solid particles trapped inside; (b) degassing the gelled mixture under reduced pressure or under vacuum conditions to remove the expandable fluid from the gelled mixture; (c) introducing water into the degassed gelled mixture with sufficient agitation to inactivate the gelled mixture so that the microspheres separate from each other; Y (d) remove acetone and water to result in a dry powder that flows freely. 2. The method of claim 1, further comprising: (e) coating the microspheres with a film-forming material to form a liquid impermeable membrane on top. 3. The method of claim 2, wherein the liquid impermeable membrane comprises one or more materials selected from the group consisting of homo- or co-polymers of acrylate, homo- or co-polymers of methacrylate, homo- or co-polymers of vinyl pyrrolidone, silicone gums, silicone waxes, silicone oils, silicone resins, esters, hydrocarbons, celluloses, fatty acids, fatty alcohols and inorganic materials, and in which, more preferably, the membrane impermeable to Liquids comprise cross-linked dimethicone or trimethylated silica treated with dimethyl siloxane. 4. The method of any one of claims 1-3, wherein the solid particles have an average particle size in the range between about 0.001 micrometers and about 0.1 micrometers. 5. The method of any one of claims 1-4, wherein the collapsed polymeric shell comprises at least one synthetic polymer obtained by polymerization of one or more ethylenically unsaturated monomers selected from the group consisting of vinylidene chloride, vinyl chloride , acrylonitrile, acrylic acid and its aliphatic or aromatic esters C1-C20, methacrylic acid and its aliphatic or aromatic esters C1-C20, acrylamide, methacrylamide, vinyl pyrrolidone, alkenes, styrene, ethylene, propylene, butylene, methylpentene and 1,3- Butadiene, preferably, in which the collapsed polymeric shell comprises at least one synthetic thermoplastic polymer selected from the group consisting of polyesters, polyamides, polyphthalamides, polyimides, polycarbonates, polyketones, cellulose acetate, polysulfones, polyphenylene sulfides, phenylene polyoxides, lactic polyacids, polyvinylpyrrolidone, polystyrene, polyacrylonitrile, polyacrylamide, polymethacryl methyl can, polyacrylates and copolymers thereof and, more preferably, in which the collapsed polymeric shell comprises a copolymer of vinylidene chloride, acrylonitrile and / or methyl methacrylate. 6. The method of any one of claims 1-5, wherein the entrapped solid particles comprise one or more materials selected from the group consisting of talc, caolm, mica, bismuth oxychloride, chromium hydroxide, barium sulfate, methyl polymethacrylates (PMMA), boron nitride, nylon beads, polymer powders, silica, silica beads, color lacquers, metal oxides, iron oxide, chromium oxide, zinc oxide, titanium dioxide and filter agents Solar physical and chemical. 7. The method of any one of claims 1-6, wherein the entrapped solid particles comprise one or more materials capable of generating oxygen free radicals. 8. The method of any one of claims 1-7, wherein the trapped solid particles comprise one or more metal oxides, preferably, wherein the trapped solid particles comprise titanium dioxide, zinc oxide or a combination of the same. 9. A microsphere formed by the method of any one of claims 1-8. 5 10 fifteen twenty 25 30 35 10. A topical composition comprising a dispersion of microspheres formed by the method of any one of claims 1-8, in a cosmetically or pharmaceutically acceptable carrier. 11. The composition of claim 10, further comprising at least one organic compound susceptible to oxidative decomposition or degradation, preferably, wherein said organic compound is an organic sunscreen agent, or an organic dye. 12. A topical sunscreen composition comprising a dispersion of microspheres formed by the method of any one of claims 1-5 in a cosmetically or pharmaceutically acceptable vehicle, wherein each of said microspheres comprises a collapsed polymeric shell having trapped inside one or more solid particles comprising titanium dioxide, zinc oxide or a combination thereof. 13. The topical sunscreen composition of claim 12, further comprising at least one organic sunscreen agent, preferably, wherein the at least one organic sunscreen agent is selected from the group consisting of 4.4 ' -t-Butyl methoxydibenzoylmethane, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, 2-ethylhexyl salicylate, 3,3,5-trimethylcyclohexyl salicylate, 2-ethylhexyl p-methoxycinnamate, 2-hydroxy-4- methoxybenzophenone, 2,2-dihydroxy-4-methoxybenzophenone, 2,4-bis- [4- (2-ethylhexyloxy) -2-hydroxyphenyl] -6- (4-methoxyphenyl) -1,3,5-triazine, methylene bis - benzotriazolyl tetramethylbutylphenol, terephthalylidene dialkafor sulfonic acid, diethylhexyl 2,6-naphthalate, ethyl 4- [bis (hydroxypropyl)] aminobenzoate, 2- (4-diethylamino-2-hydroxybenzoyl) benzoate, n-hexyl pzo glycerol aminobenzoate, methylantranilate, p-dimethylaminobenzoic acid or aminobenzoate, 2-ethylhexyl p-dimethylaminobenzoate, 2-phenylbenzimidazole-5-sulfonic acid, acid 2- (p-dimethylaminophenyl) -5-sulfonium benzoxazoic acid and mixtures or combinations thereof and, more preferably, in which the at least one organic sunscreen agent is 4,4'-t-butyl methoxy dibenzoylmethane. 14. The topical sunscreen composition of claim 13, further comprising a second organic sunscreen agent. 15. The topical sunscreen composition of claim 11, wherein the at least one organic sunscreen agent is encapsulated in protective structures, preferably wherein the protective structures comprise additional microspheres with collapsed polymeric shells, in which this caught the at least one organic sunscreen agent. 16. The topical sunscreen composition of any one of claims 12-15, wherein at least some of the microspheres have titanium dioxide particles trapped therein, in which at least some of the microspheres have particles of zinc oxide trapped inside, or in which some of the microspheres have titanium dioxide particles trapped inside and the others have zinc oxide particles trapped inside. 17. The topical sunscreen composition of any one of claims 12-16, further comprising one or more antioxidants, preferably, wherein said one or more antioxidants are co-entrapped with the solid particles within the collapsed polymeric shell. of each microsphere, or the microspheres are applied as a coating, or they are solubilized or dispersed in the cosmetically or pharmaceutically acceptable vehicle.