WO2023139331A1 - New cosmetic use of closed-porosity porous spheres of metal oxide - Google Patents

Abstract

The invention relates to the cosmetic use of closed-porosity porous spheres containing a metal oxide for improving the appearance and/or comfort of the skin and skin appendages, particularly hair and/or mucous membranes. The invention further relates to a cosmetic or pharmaceutical composition which contains said spheres.

Description

New cosmetic use of closed porosity porous spheres of metal oxide

Technical area

The present invention relates to the cosmetic use of porous spheres with closed porosity of metal oxide to improve the aesthetic appearance and the comfort of the skin, of the skin appendages, in particular of the hair and/or of the mucous membranes, as well as said cosmetic compositions and the methods of cosmetic treatment which result therefrom. The present invention also relates to pharmaceutical compositions, in particular dermatological compositions, comprising porous spheres with closed porosity of metal oxide to improve the comfort of the skin, skin appendages and/or mucous membranes exhibiting a pathological state.

Visibly improving the appearance of skin and hair is one of the main challenges of cosmetics. Consumers of cosmetic products are constantly in demand for cosmetic solutions for effectively masking signs of the skin and/or hair that are considered unsightly. These signs appear naturally with aging but can also result from chronic exposure to various factors. These may be environmental factors such as pollution, wind, climatic variations, in particular excessive temperature variations, in particular due to air conditioning, and drought. It can also be aggressive factors of a mechanical nature such as shaving, rubbing and hair removal, and/or aggressive factors of a chemical nature such as hair treatments, in particular (de)colouring, permanent wave and straightening, detergents, exfoliating treatments. These factors cause damage to the skin, cutaneous appendages and/or mucous membranes which result in visible manifestations often considered unsightly. Intrinsic factors contribute to their appearance, in particular stress, hormonal variations, taking weight, dieting, dehydration and aging. Genetics, in particular the type of skin (sensitive, hyperseborrhoeic, reactive, etc.) and ethnic origin, for example Caucasian, Asian or African, also plays an important role in the appearance of certain manifestations.

The unsightly cutaneous manifestations are in particular wrinkles and fine lines, such as, for example, frown lines and crow's feet. They can be expression lines or aging lines. These are initially superficial and then become deeper, such as the nasolabial folds. The cutaneous manifestations also include signs of loss of volume, in particular sagging skin, sagging facial contours leading to sagging facial features which give a sad or tired appearance, or even loss of density which results in thinner, more fragile skin, which is accompanied by a loss of radiance and/or a so-called dull complexion. Thus, unsightly skin manifestations also include manifestations of color, shine and pigmentation such as loss of evenness of complexion, radiance, dark circles, puffiness, redness, brown spots or age or white spots, in particular vitiligo, rosacea, pregnancy mask, melasma, nevus, angioma. They also include skin imperfections such as blackheads, visible pores, pimples, scars including acne marks, burn marks, wounds, stretch marks but also rough skin and flaking. At the level of the mucous membranes, the unsightly manifestations are generally signs of dehydration such as scales and/or cracks. At the level of the hair, the unsightly manifestations are generally dull, depigmented, brittle, difficult to comb hair, in particular unruly, with split ends.

These manifestations, particularly those which are expressed at the level of the face and the eyes, are particularly perceived as unsightly by consumers. If some of them can be corrected by cosmetic surgery, this is not always the case and the result is sometimes unsatisfactory because partial, perceived as unnatural, irritating or even painful and often expensive. Many consumers cannot afford it or are opposed to it. Many cosmetic alternatives exist to mask or reduce these undesirable manifestations. Makeup, in particular foundations, aim to provide a solution to hide wrinkles and even out the complexion. But consumers are also looking for a good-looking effect that remains natural, without transferring pigments onto clothes, as well as a well-being effect during application.

The blurring effect or "soft focus" in the cosmetics industry is used in anti-aging creams and in make-up. Skin surface imperfections such as fine lines and wrinkles make skin appear uneven by trapping light in the micro-crevices formed by wrinkles. The trapped light is then absorbed and generates dark spots which will appear on the surface of the skin. There are special pigments and/or particles, e.g. transparent alumina pads coated with a thin layer of titanium dioxide, designed to create this soft-focus effect by uniformly diffusing light on the surface of the skin. Wrinkles and fine lines are masked by remaining quite translucent over the entire surface of the skin, which gives a natural appearance to the skin while diminishing the appearance of imperfections. To obtain this “soft-focus” effect, the pigments/particles must show optical properties of:

- high total transmittance (overall transmission of light) to give a natural appearance and

- diffusion ("haze") to its maximum to form a translucent and uniform light distribution. Thus, the appearance of fine lines and wrinkles will be greatly minimized, helping older consumers to look younger and have more radiant skin.

Total transmittance is influenced by light absorption and reflection while Haze is influenced by light scattering. Haze is an important appearance attribute as it directly affects human perception and plays an important role in consumer demand. It translates the degree of blurring or haze of a transparent material. Its value is expressed as a percentage. The higher its value, the greater the blurring.

Porous metal oxide spheres have already been described in patent applications WO2020/183108 and WO2020/182936 in the context of cosmetic applications and in particular for improving the appearance of the skin, skin appendages and/or mucous membranes, in particular by masking unsightly manifestations. However, these spheres have an open porosity and therefore do not have closed pores as illustrated in FIG. IB. The % of closed pores by volume of these spheres is thus less than 5%.

The inventors have surprisingly found that closed porosity porous spheres of metal oxide have an improved effect on masking imperfections compared to the open porosity porous spheres of the prior art. Indeed, such spheres have a higher value of total transmittance and of haze or diffusion (“haze”), thus making it possible to improve their blurring/masking (“soft focus”) property. In addition, such spheres are easier to formulate because the external formulation medium, and in particular the compounds present in this medium, cannot penetrate them, which allows them to keep a constant net refractive index regardless of the formulation medium and/or the type of formulation and therefore to avoid a modification of their optical property and therefore of their masking property depending on the formulation medium used. These spheres are particularly illustrated in Figure IB.

Disclosure of Invention

The present invention thus aims to meet this constant need for a cosmetic alternative to improve the appearance of the skin, of the skin appendages and/or of the mucous membranes, in particular by masking the unsightly manifestations, advantageously by a “soft focus” effect. The present invention also aims to provide a new cosmetic ingredient which is also easy to formulate, and devoid of side effects, in particular which does not induce irritation on the skin. The spheres according to the invention indeed have the unique ability to reflect, to diffuse light and thus make it possible to smooth the surface of the skin, of the cutaneous appendages and/or of the mucous membranes and thus to hide their unsightly manifestations and to increase their radiance. They also give a soft and silky feel to the composition that contains them.

The spheres according to the invention offer the advantage of being suitable for all skin types, regardless of type, complexion and radiance. Another advantage of the present invention is that the spheres have great stability and can be used in powder form or in composition. They are inert, which makes it possible to formulate them easily in any kind of cosmetic or dermatological compositions, whether these are lipophilic or hydrophilic.

Another advantage is that the spheres can be used with the conventional ingredients of cosmetic compositions, in particular for make-up and/or cosmetic care, in particular pigments or color agents to contribute to masking unsightly manifestations, in particular imperfections. According to an advantageous embodiment, the spheres according to the invention can be used in foundations and/or make-up and/or care products.

A subject of the present invention is thus the non-therapeutic cosmetic use of porous spheres with closed porosity comprising a metal oxide to improve the appearance and/or the comfort of the skin, of the skin appendages, in particular the hair, and/or of the mucous membranes.

According to the invention, the term "porous spheres with closed porosity" means spheres of which the majority (more than 50% by volume) of the pores consists of closed pores, that is to say having no opening on the outside of the sphere. In particular at least 90% by volume of the pores are closed pores, more advantageously at least 95% by volume of the pores are closed pores, even more advantageously at least 99% by volume of the pores are closed pores. The % by volume of pores closed is measured based on the images obtained by scanning electron microscopy (SEM) of the spheres. It can be defined as the ratio between the number of closed pores / the total number of pores. Since the volume of each pore, whether open or closed, is the same, the % by number is the same as the % by volume.

In an advantageous embodiment, the closed pores of the spheres according to the invention are not interconnected with each other. Thus in this case, the spheres according to the invention contain several pores (at least two pores) not only closed towards the outside of the sphere but also not interconnected with each other. The porous sphere according to the invention is therefore advantageously not a hollow sphere. Each pore will thus comprise a volume of void (in particular containing air) inaccessible to the formulation medium, in particular to polymers, oligomers and to molecules having a molecular weight greater than 5000 g/mol. In an advantageous embodiment, the closed pores are of spherical shapes. According to the invention, the term “spheres” or “spherical” means particles or pores whose shape has an aspect ratio (“aspect ratio”) or width/height ratio close to 1, advantageously between 0.9 and 1.1, more particularly between 0.95 and 1.05, in particular between 0.99 and 1.01, even more particularly of approximately 1.

In another advantageous embodiment, the spheres according to the invention do not contain open pores and/or interconnected pores.

Advantageously, the size distribution of the closed pores of the spheres according to the invention is monodisperse or bimodal, advantageously monodisperse.

According to a preferred embodiment, the porous spheres with closed porosity according to the invention have an average diameter measured by scanning electron microscopy (SEM) ranging from 0.5 μm to 100 μm and/or an average porosity ranging from >0.10 to 0.80 and/or an average pore diameter, in particular of closed pores, measured by scanning electron microscopy (SEM) ranging from 50 nm to 800 nm, advantageously 50 nm at 500nm.

According to another preferred embodiment, the porous spheres with closed porosity according to the invention have an average diameter measured by scanning electron microscopy (SEM) ranging from 1 μm to 100 μm and/or an average porosity ranging from >0.10 to 0.80 and/or an average pore diameter, in particular of closed pores, measured by scanning electron microscopy (SEM) ranging from 50 nm to 800 nm, advantageously from 50 nm to 500nm.

Advantageously, the porous spheres with closed porosity according to the invention have a mean diameter measured by scanning electron microscopy (SEM) ranging from 0.5 μm to 100 μm and a mean porosity ranging from >0.10 to 0.80 and a mean pore diameter, in particular of closed pores, measured by scanning electron microscopy (SEM) ranging from 50 nm to 800 nm. Particularly advantageously, the porous spheres with closed porosity according to the invention have an average diameter measured by scanning electron microscopy (SEM) ranging from 1 μm to 100 μm and an average porosity ranging from >0.10 to 0.80 and an average diameter of pores, in particular of closed pores, measured by scanning electron microscopy (SEM) ranging from 50 nm to 800 nm.

Preferably, the metal oxide of the porous spheres with closed porosity according to the invention is chosen from silicon, titanium, aluminum, zirconium, cerium, iron oxide, zinc oxide, indium oxide, tin oxide, chromium oxide, mixed metal oxide and their combinations, preferentially silicon, titanium, aluminum and zinc oxide and their combinations, even more preferentially silicon oxide, titanium and their combinations. , particularly advantageously, silicon oxide.

In an advantageous embodiment, the porous spheres with closed porosity according to the invention comprise from 60% by weight to 99.9% by weight of metal oxide and from 0.1% by weight to 40% by weight of light-absorbing agents, by total weight of the spheres, advantageously from 0.1% by weight to 40% by weight of carbon black.

Preferably, the porous spheres with closed porosity according to the invention have an average diameter measured by scanning electron microscopy (SEM) ranging from 1 μm to 100 μm and an average pore diameter measured by scanning electron microscopy (SEM) ranging from 50 nm to 800 nm.

Preferably, the porous spheres with closed porosity according to the invention have an average diameter measured by scanning electron microscopy (SEM) ranging from 1 μm to 75 μm and an average porosity ranging from 0.45 to 0.70, preferentially from 0.5 to 0.65.

According to a particular embodiment of the invention, the porous spheres with closed porosity according to the invention have an average diameter measured by scanning electron microscopy (SEM) ranging from 2.5 μm to 8 μm, an average porosity ranging from 0.45 to 0.70 and an average pore diameter, in particular of closed pores, measured by scanning electron microscopy (SEM) ranging from 100nm to 200nm.

Advantageously, the use according to the invention is to reduce the visibility of unsightly manifestations of the skin, skin appendages and/or mucous membranes, in particular irregularities in the relief and/or texture of the skin, mucous membranes and/or skin appendages, and/or irregularities in the color of the skin and/or mucous membranes.

According to a particular embodiment of the invention, the porous spheres with closed porosity according to the invention are present in a cosmetic composition, at a concentration ranging from 1x10 ³ to 10% by weight, preferably from 0.5% to 5% by weight relative to the total weight of the composition.

Advantageously, the use according to the invention is for improving the organoleptic properties of the cosmetic composition.

A subject of the present invention is also a cosmetic care process for improving the appearance and/or the comfort of the skin, of the skin appendages, in particular the hair, and/or of the mucous membranes, comprising the topical application to at least one area of the skin and/or of the skin appendages and/or of the mucous membranes of porous spheres with closed porosity comprising a metal oxide and/or of a cosmetic composition comprising them.

In particular, the porous spheres with closed porosity are as described above.

Advantageously, the cosmetic care process according to the invention is for reducing the visibility of unsightly manifestations of the skin, skin appendages and/or mucous membranes, in particular irregularities in the relief and/or texture of the skin, mucous membranes and/or appendages. cutaneous, and/or irregularities in the color of the skin and/or mucous membranes.

In an advantageous embodiment, the area of skin of the body and/or the appendix of the skin and/or mucosa is chosen from the skin of the face, including the forehead, the cheeks, the nose, the temples, the so-called "T" area (forehead, nose and chin), under the eyes, the periorbital area, in particular dark circles, the chin, the scalp, the neck, the back, the shoulders, the arms, the forearms, the thorax, the hands, the hair, the beard, eyelashes, eyebrows, bust, in particular the neckline, stomach and/or armpits, legs, feet, hands, neck, thighs, hips, buttocks, waist, torso, lip contour, hair, hair and/or ocular, labial and/or oral mucosa, preferably the skin of the face, hands, neckline.

A subject of the present invention is also the cosmetic compositions containing these porous spheres with closed porosity, in particular for the uses mentioned, and optionally a cosmetically acceptable excipient.

Advantageously, the cosmetic composition according to the invention is in the form of a serum, a lotion, a cream, a shampoo, a conditioner, an oil, a milk, an ointment, a paste, a mousse, an emulsion, a hydrogel, a shower gel, a mask, a lacquer, a spray, a wax, a powder, in particular make-up, or a stick.

Advantageously, the cosmetic composition according to the invention is in the form of a slightly gelled composition and/or comprises an oily phase, preferably it is of the oily composition or oil-in-water or water-in-oil emulsion or lotion type.

The present invention also relates to pharmaceutical compositions, in particular dermatological compositions containing these porous spheres with closed porosity, and optionally an excipient pharmaceutically acceptable, in particular dermatologically acceptable.

The present invention also relates to a pharmaceutical composition according to the invention, preferably dermatological, for its use to improve the comfort of the skin, appendages and / or mucous membranes, in particular having a pathological state, in particular manifested by a loss of homogeneity and / or deregulation and / or irregularity of the color, complexion, sebum secretion and / or relief, such as hyperpigmented, hypopigmented, hyperseborrheic skin , reactive, inflammatory, atopic, in particular skin affected by vitiligo, melanoma, rosacea, telangiectasia, acne, rosacea, urticaria, psoriasis, herpes, impetigo, ecthyma, erysipelas, and/or with wounds and/or scars, in particular acne, pimples, boils, varicose veins, melasma, follicles itis, abscesses, any combination thereof.

The present invention also relates to the use of porous spheres with closed porosity according to the invention for the preparation of a pharmaceutical composition according to the invention, preferably dermatological, intended to improve the comfort of the skin, appendages and/or mucous membranes, in particular having a pathological state, in particular manifested by a loss of homogeneity and/or a deregulation and/or an irregularity of the color, of the complexion, of the secretion of sebum and/or of the relief, such as hyperpigmented, hypopigmented, hyperseborrheic, reactive, inflammatory, atopic skin, in particular skin affected by vitiligo, melanoma, rosacea, telangiectasia, acne, rosacea, urticaria, psoriasis, herpes, impetigo, ecthyma, erysipelas, and/or presenting wounds and/or scars, in particular acne, pimples , boils, varicose veins, melasma, folliculitis, abscesses, any combination thereof. Such cosmetic or pharmaceutical compositions, preferably dermatological, advantageously comprise the spheres at a concentration ranging from 1×10 ³ to 10% by weight, preferably from 0.5% to 5% by weight relative to the total weight of the composition.

The use according to the invention is preferentially cosmetic, and by topical application to at least one zone concerned or a part of healthy skin, healthy mucous membrane and/or healthy skin appendages, preferentially the hair, preferentially in humans.

Within the meaning of the present invention, the term “cosmetic use” means a non-therapeutic, non-pharmaceutical use of the spheres according to the invention, preferably on healthy skin, in particular a healthy scalp, and/or healthy skin appendages, in particular healthy hair, and/or healthy mucous membranes.

Within the meaning of the present invention, part of skin, preferably scalp, and/or mucosa and/or skin appendages, and/or area of skin, preferably scalp, and/or mucosa and/or so-called "healthy" skin appendages, means a part of the skin, preferably scalp, and/or mucosa and/or skin appendages, and/or an area of skin, preferably scalp, and/or mucosa and/or skin appendages qualified non-pathological by a dermatologist, that is to say, which does not present with infection, inflammation, in particular in the form of sunburn, disease or skin conditions such as folliculitis, candidiasis, psoriasis, ichthyosis, eczema, acne, impetigo, boils, abscesses, herpes, ecthyma, erysipelas or dermatitis, varicose veins, rosacea or telangiectasia, pathology s or wounds or burns, sunburn or wounds or does not suffer from solar elastosis, which is not reactive or atopic skin. It is in particular a part of skin and/or mucous membrane made up of cells described as “normal” by a doctor, that is to say non-cancerous cells.

The term "topical application" or "topical application", used here, means applying the spheres according to the present invention optionally in the form of active ingredient and / or composition on the surface of the skin including the scalp, the skin appendages in particular the hair, and / or the mucous membranes in particular by direct application or by vaporization.

The term “improving the appearance” means reducing or reducing the visibility of the unsightly manifestations, in particular masking them, hiding them, preferentially those present on the face, in particular by filling and/or by optical effect.

According to the present invention, "unsightly manifestations" are unsightly irregularities in the relief and/or texture of the skin, mucous membranes and/or skin appendages and/or irregularities in the color of the skin, mucous membranes and/or skin appendages.

According to the present invention, the unsightly irregularities in the relief and texture of the skin are wrinkles and fine lines, in particular frown lines and crow's feet, asperities, blackheads, dilated pores, rough appearance, marks and scars, in particular those due to injuries, acne, pimples, burns and/or stretch marks.

According to the present invention, the irregularities in the color of the skin are pigment spots, in particular white or dark spots, in particular age spots or hyperpigmented or depigmented spots, pregnancy mask, moles, melanomas, freckles, redness, but also loss of complexion radiance, dull complexion, dark circles and puffiness, rosacea, rosacea.

According to a preferential mode, the unsightly manifestations are selected from wrinkles, fine lines, blackheads, pores visible, loss of complexion radiance, dullness, dark circles, puffiness, pigment spots and any combination thereof.

The unsightly manifestations of the cutaneous appendages, preferentially of the hair, are dull, brittle. For hair and hair, the manifestations also include the brittle, crumbly, damaged appearance and/or the difficulty in shaping them, in particular for the hair, in combing them, and/or split ends.

The unsightly manifestations of the mucous membranes include a dull, cracked, withered and/or damaged appearance as well as scales.

In general, the improvement in unsightly manifestations can be visualized and evaluated by microscopy and/or by high-resolution photography analysis with, in particular, measurement of the shine of the area of skin, mucosa and/or skin appendages.

The improvement in the radiance of the complexion, known as “radiance” or “glow” in English, can in particular be measured by an objective instrumental method. This in vivo measurement method consists of taking high-resolution photographs in a cross-polarized configuration of the faces of volunteers at 45° before and after application of the tested product. Based on these digital photographs, an image analysis makes it possible to extract and quantify specific parameters (for example: L*, a*, b*, C, h°) related to the color, radiance, homogeneity, and texture of the skin.

Similarly, the so-called "gloss" in English can in particular be measured according to this method on the basis of high-resolution photographs in cross-polarized and parallel-polarized configuration of the face of the volunteers taken at 45° before and after application of the tested product. Based on these digital photographs, an image analysis makes it possible to extract and quantify specific parameters related to gloss such as specular gloss and contrast gloss. Within the meaning of the present invention, “reducing the visibility of skin pores” means the fact of masking skin pores, in particular by filling and/or by optical effect.

The visibility of skin pores can be demonstrated in vivo by an objective instrumental method (image analysis) which makes it possible to extract and quantify specific parameters from high-resolution photographs in cross-polarized configuration of the face of volunteers before and after application of a composition comprising the spheres according to the invention. The density of skin pores can also be measured in vivo by imaging, in particular by the fringe projection technique, by measuring the so-called curvature parameter.

In a preferred embodiment of the invention, the spheres according to the invention are in an effective amount to reduce the visibility of the pores of the skin by at least 10%, preferentially by at least 20%, after application of a cream comprising the spheres according to the invention, more preferentially prepared under the conditions described in one of Examples 1 to 7, preferentially formulated in the form of a cosmetic composition such as that described in Examples 9 and 10.

The term “mucosa” is understood to mean the ocular mucosa, the vaginal mucosa, the uro-genital mucosa, the anal mucosa, the nasal mucosa and/or the buccal, labial and/or gingival mucosa, preferentially, the ocular and/or buccal and/or labial and/or gingival mucous membranes.

In the context of the present invention, the term "improving comfort" means increasing the organoleptic properties, in particular the touch and the ease of spreading of the composition, in particular by a soft, silky, light, and smooth touch, but also conferring a feeling of suppleness on the area to which the composition containing the spheres has been applied. The organoleptic properties and in particular the feel of a composition can be evaluated according to conventional methods in the field in particular by evaluation by people trained to carry out sensory tests on the skin. For a better evaluation, the measurement is carried out by comparison with a placebo, that is to say the same composition which does not contain the spheres according to the invention. This evaluation is preferably carried out on an emulsion.

Advantageously, the improvement in comfort is analyzed by sensory evaluation of an emulsion as described in Example 9. A panel of trained people evaluates the compositions by applying a defined quantity of composition to their forearm. According to a defined procedure, the composition is spread on the skin and its specific characteristics are evaluated such as, for example, its absorption, the softness, the appearance by comparison with a placebo composition. A value from -1 to +1 is given. For example, for the sensation of lightness, the tested composition can be evaluated +1 to indicate that it is much lighter than the so-called placebo reference composition or slightly less light than the placebo composition with the value −0.5.

If two compositions provide the same perception then people indicate the value 0 for the evaluated parameter. Such evaluations are carried out in the same way for the tested composition and the reference composition, under the same climatic conditions and blind. A statistical analysis is then used to assess the significance and the differences in the results of the assessment.

According to the invention, the term "cutaneous appendages" means the hair, the eyelashes, eyebrows, the beard, the mustache and/or the nails, preferably the hair.

Advantageously, the use according to the present invention makes it possible to improve the appearance of the skin by improving the radiance of the complexion, by making it more uniform, shiny, by providing a good-looking, fresh, luminous effect, in particular by hiding the unsightly manifestations of texture, relief and / or color of the skin. According to another embodiment, the spheres according to the invention also make it possible to soften the skin and/or the mucous membranes and/or the skin appendages which shows signs of discomfort, in particular the skin and/or the mucous membranes and/or the skin appendages having been exposed to aggressive conditions of a mechanical nature such as shaving, friction, drying, wind, sun, and hair removal, and/or of a chemical nature such as hair treatments, in particular (discoloration), permanent wave and straightened age, detergents, exfoliating treatments.

According to a particular mode, the use according to the present invention makes it possible to illuminate, to illuminate the skin, the cutaneous annexes, in particular the hair and / or the mucous membranes, to make them more uniform, to create a blur in particular called "soft-focus", to soften the features, to fill in the irregular features and the marks in particular as a filling agent in particular for wrinkles.

The spheres or microspheres according to the invention are porous metal oxide spheres with closed porosity. Such spheres are photonic beads, which means that they exhibit a degree of periodic variations in color, in particular which have an impact on light waves including the perception of color, clarity, transparency, brilliance.

The spheres according to the invention comprise a metal oxide and preferably have an average diameter measured by scanning electron microscopy (SEM) ranging from 0.5 μm to 100 μm and/or an average porosity ranging from >0.10 to 0.80 and/or an average pore diameter, in particular of closed pores, measured by scanning electron microscopy (SEM) ranging from 50 nm to 500 nm.

The microspheres or porous spheres with closed porosity according to the invention mainly contain the metal oxide. Advantageously, they consist essentially of the metal oxide. Preferably, they consist exclusively of metal oxide. Advantageously, the porous spheres with closed porosity according to the invention comprise between 60% and 99.9% of metal oxide, preferably at least 70%, more preferably at least 80%, more preferably at least 90%, more preferably 99.9% of metal oxide, by weight relative to the total weight of the spheres. Thus, in an advantageous embodiment, the porous spheres according to the invention contain at least 70% metal oxide, by weight relative to the total weight of the spheres.

According to the invention, the metal oxides include transition metal oxides, metalloids and earth metals compatible with cosmetic and/or dermatological use, such as for example silica, titanium, alumina, zirconia, cerium, iron oxide, zinc oxide, indium oxide, tin oxide, chromium oxide, mixed metal oxide, combinations thereof. The metal oxide is preferably chosen from the group consisting of SiO ₂ , TiO ₂ , ZnO and their mixtures, advantageously from the group consisting of SiO ₂ , TiO ₂ and ZnO, more advantageously from the group consisting of SiO ₂ , ZnO and their mixtures, even more advantageously from the group consisting of SiO ₂ and ZnO, in particular it is SiO ₂ . In an advantageous embodiment, the metal oxides do not include TiO ₂ and/or a mixture of several metal oxides.

In a particular embodiment, the porous spheres with closed porosity according to the invention, in particular of which at least 90% of the pores are closed pores, have an average diameter measured by scanning electron microscopy (SEM) ranging from 1 μm to 100 μm and an average pore diameter measured by scanning electron microscopy (SEM) ranging from 50 nm to 800 nm and comprise at least 70% metal oxide. In particular, these spheres and do not contain TiO ₂ and/or are not used in combination with an anti-UV filter and/or in a composition comprising it. In an advantageous embodiment, the porous spheres with closed porosity according to the invention can comprise, for example, from 60% by weight to 99.9% by weight of metal oxide and from 0.1% by weight to 40% by weight of light-absorbing agents, by total weight of the spheres. According to one embodiment of the invention, the porous spheres with closed porosity according to the invention contain 0.3%, preferably 0.5%, preferably at least 1%, more preferably at least 5% by weight of light-absorbing agents, relative to the total weight of the spheres.

According to an alternative and preferential mode, the porous spheres with closed porosity according to the invention do not contain any light absorber and/or the cosmetic composition which contains them does not contain any light absorber either. Indeed, light absorbers such as TiCh can present a certain toxicity. However, the inventors have surprisingly discovered that even without a light absorber, the microspheres or spheres according to the invention have an immediate anti-blue light filter effect.

Advantageously, the light-absorbing agent(s) are selected from the group consisting of organic and inorganic pigments, compatible with a cosmetic and/or dermatological application, in particular on the skin, the mucous membranes and/or the skin appendages, more particularly it is carbon black.

According to an advantageous preferred mode, the porous spheres with closed porosity according to the invention have an average diameter measured by scanning electron microscopy (SEM) ranging from 0.5 μm to 100 μm, advantageously from 1 μm to 100 μm. in this case they are microspheres. Thus, advantageously, they are not nanospheres in order to avoid their penetration into the deep layers of the skin and/or of the mucous membranes and to preferentially have a surface effect. THE microspheres according to the invention therefore advantageously remain on the surface of the skin and/or of the mucous membranes and/or of the skin appendages.

By “on a micrometric scale” or “micro-” is meant a size ranging from about 0.5 μm to about 999 μm. By “nano-scale” or “nano-” is meant a size ranging from about 1 nm to about 999 nm.

More advantageously, the porous spheres with closed porosity according to the invention have an average diameter measured by scanning electron microscopy (SEM) ranging from 1 μm to 75 μm, preferentially from 2 μm to 70 μm, preferentially from 3 μm to 65 μm, from 4 μm to 60 μm, from 5 μm to 55 μm or from 5 μm to 50 μm, more preferably from 10 μm to 25 μm, for example an average diameter measured by micro scanning electron microscope (SEM) selected from 1 pm, 2 pm, 3 pm, 4 pm, 5 pm, 6 pm, 7 pm, 8 pm, 9 pm, 10 pm, 11 pm, 12 pm, 13 pm, 14 pm, 15 pm, 16 pm, 17 pm, 18 pm, 19 pm, 20 pm, 21 pm, 22 pm, 23 pm, 24 pm, 25 pm 26 pm, I pm, 28 pm, 29 pm or 30 pm.

In an alternative embodiment, the porous spheres with closed porosity according to the invention have a mean diameter measured by scanning electron microscopy (SEM) selected from 4pm, 8.7pm, 9.0pm, 9.3pm, 9.6pm or 9.9pm,

In an alternative embodiment, the porous spheres with closed porosity according to the invention have an average diameter measured by scanning electron microscopy (SEM) ranging from 1.3 μm to 10 μm, more particularly from 1.5 to 9.9 μm, even more particularly from 2.5 μm to 8 μm, for example an average diameter chosen from 1 μm, 2 μm, 2.6 μm, 2.9 μm, 3 μm, 4 μm, 5 μm, 6pm, 6.7pm, 7pm, 8pm, 9pm, 10pm. In a preferred mode of the invention, the average diameter of pores, in particular of closed pores, of the porous spheres with closed porosity according to the invention, measured by scanning electron microscopy (SEM), ranges from 50 nm to 800 nm, advantageously from 50 nm to 500 nm, advantageously from 80 nm to 250 nm, advantageously from 100 nm to 245 nm, in particular from 100 nm to 200 nm, more particularly from 145 nm to 180 nm, more particularly from 150 nm to 160 nm, even more particularly from 150 nm to 155 nm, for example chosen from: 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, 105 nm, HOnm, 115 nm, 120 nm, 125 nm, 130 nm m, 135 nm, 140 nm, 145 nm, 150 nm, 153 nm, 155 nm, 160 nm, 165 nm, 170 nm, 175 nm, 180 nm, 185 nm, 190 nm, 191 nm, 192 nm, 193 nm, 194 nm, 1 95nm, 196nm, 197nm, 198nm, 199nm, 200nm, 201nm, 202nm, 203nm, 204nm, 205nm, 206nm, 207nm, 208nm, 209nm, 210nm, 211nm, 212nm , 213nm, 214nm, 215nm, 216nm, 217nm, 218nm, 219nm, 220nm, 225nm, 230nm, 235nm, 240nm, 245nm, 250nm 260nm, 280nm, 300nm, 320 nm, 340nm, 360nm, 380nm, 400nm, 420nm,

440nm, 460nm, 480nm, 500nm, 520nm, 540nm, 560nm, 580nm,

600nm, 620nm, 640nm, 660nm, 680nm, 700nm, 720nm, 740nm,

760nm, 780nm or 800nm.

In an alternative embodiment, the porous spheres according to the invention have an average diameter measured by scanning electron microscopy (SEM) ranging from 1.3 μm to 10 μm, more particularly from 1.5 to 9.9 μm, even more particularly from 2.5 μm to 8 μm, for example an average diameter chosen from 1 μm, 2 μm, 2.6 μm, 2.9 μm, 3 μm, 4 μm, 5 μm, 6 μm, 6 μm 7µm, 7µm, 8µm, 9µm, 10µm; and an average porosity chosen from 0.45, 0.47, 0.49, 0.50, 0.51, 0.53, 0.55, 0.57, 0.59, 0.61, 0.63, 0.65, 0.67, 0.69 or 0.70; and an average pore diameter measured by scanning electron microscopy (SEM) from 100 nm to 200 nm, more particularly from 145 nm to 180 nm, more particularly from 150 nm to 160 nm, even more particularly from 150 nm to 155 nm, for example chosen from: 100 nm, 105 nm, HOnm, 115 nm, 120 nm, 125nm, 130nm, 135nm, 140nm, 145nm, 150nm, 153nm, 155nm, 160nm, 165 nm, 170 nm, 175 nm, 180 nm, 185 nm, 190 nm, 191 nm, 192 nm, 193 nm, 194 nm, 195 nm, 196 nm, 197 nm, 198 nm, 199 nm or 200 nm.

In the porous sphere according to the invention, the mean diameter of the spheres is markedly larger than the mean diameter of the pores. For example, the average diameter of the spheres is in general at least 25 times, preferentially at least 30 times, preferentially at least 35 times, more preferentially 4 times greater than the average diameter of the pores.

In some embodiments, the ratio of the average sphere diameter to the average pore diameter is at least 40/1, at least 50/1, at least 60/1, at least 70/1, at least 80/1, at least 90/1, at least 100/1, at least 110/1, at least 120/1, at least 130/1, at least

140/1, at least 150/1, at least 160/1, at least 170/1, at least 180/1, at least 190/1, at least 200/1, at least 210/1, at least 220/1, at least 230/1, at least 240/1, at least 250/1, at least 260/1, at least

270/1, at least 280/1, at least 290/1, at least 300/1, at least 310/1, at least 320/1, at least 330/1, at least 340/1 or at least 350/1.

In a preferred mode of the invention, the porous spheres with closed porosity according to the invention have an average porosity ranging from >0.10 to 0.80, in particular chosen from: 0.4, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69 or 0.70, preferably ranging from 0.45 to 0.70, more preferably 0.50 to 0.65.

According to the invention, the size of the spheres and/or the pores is a synonym of the diameter of the spheres and/or the pores and is determined by scanning electron microscopy (SEM). The mean diameter of the spheres and/or the pores (or mean size) is understood to mean the mean diameter of the spheres and/or the pores, which can be supplemented by measuring the standard deviation. It is obtained by analyzing 100 to 150 spheres and/or 50 to 70 pores of different spheres by scanning electron microscopy using image analysis software in particular ImageJ software.

The average porosity of a sphere refers to the total pore volume, as a fraction of the volume of the entire sphere. The average porosity can also be called "volume fraction". It is a dimensionless quantity. It is calculated by the ratio between the volume of the unoccupied space (inside the pores) and the total volume of the sphere. For example, a porous silica sphere according to the invention having an average diameter of 7.6 μm and containing closed pores with an average diameter of 165 nm has an average porosity of 0.8. The diameter of the pores is determined by the diameter D50 of the polymers of nanoparticles which compose it. The larger the diameter D50 of the nanoparticle polymers that compose it, the larger the average diameter of the pores. Similarly, the concentration of the nanoparticles is adjusted according to the average diameter of the spheres that it is desired to obtain. The higher the concentration of nanoparticles, the larger the size of the spheres.

A mercury porosimetry analysis is used to characterize the porosity of the spheres. Mercury porosimetry consists of applying a controlled pressure in the sample to be measured immersed in mercury. External pressure is applied so that the mercury penetrates the pores/holes of the material. The amount of pressure needed is inversely proportional to the size of the pores/holes. The mercury porosimeter then provides pore volume and size distributions. The mercury porosimeter generates volume and pore size distributions from pressure data against intrusion data generated by the instrument using Washburn's equation.

In an advantageous embodiment, the spheres according to the invention do not contain and/or are not used in combination with an anti-blue light filter and/or an anti-UV filter and/or a sunscreen and/or in a cosmetic composition which contains them. Thus the spheres according to the invention are not used as a booster for anti-blue light filters and/or for increasing the SPF (sun protection factor) of a sunscreen composition.

In an advantageous embodiment, the porous spheres according to the invention do not comprise a coating layer on their surface containing a hydrophobic compound. In a particularly advantageous embodiment, the porous spheres according to the invention do not include a coating layer on their surface.

According to a particular embodiment of the invention, the porous spheres according to the invention do not comprise a coating layer on their surface containing a polyorganosiloxane, in particular a silicone compound.

The porous spheres comprising a metal oxide can be prepared using a mold made of polymers commonly referred to as a “polymer template” or sacrificial polymer model. Such porous spheres show a color observable by the human eye, that is to say a color observable with the naked eye, or can appear white.

“A color observable with the naked eye” means a color that is perceived by a majority of people. This can be for any sample of spheres according to the invention distributed over a given surface, for example, over 1 cm ² , 2 cm ² , 3 cm ² , 4 cm ² , 5 cm ² or 6 cm 2 , 7 cm ² , 8 cm ² , 9 cm ² , 10 cm ² , 11 cm ² , 12 cm ² , 13 cm ^{2 ,} 14 cm ² or 15 cm ² . It can also mean that it is observable by the CIE 1931 Standard Observing Model 2° and/or by the CIE 1964 Standard Observing Model 10°. The color observation background can be of different kinds, for example white, black, or any intermediate between black and white.

According to one embodiment, the spheres according to the invention are prepared by the process having the following 3 steps:

Step 1: liquid droplets are generated from a dispersion of particles, said dispersion comprising first particles (a) comprising a polymer and second particles (b) comprising a metal oxide or a metal oxide precursor. This dispersion of particles is advantageously an aqueous dispersion at a pH in the range 8-10, in particular a colloidal dispersion.

The droplets are advantageously obtained using a microfluidic device. Examples of microfluidic devices are narrow channel devices having a microscale junction adapted to produce uniform droplets, the channels being connected to a collection reservoir. Microfluidic devices contain, for example, a junction having a channel width ranging from 10 μm to about 100 μm. These devices are for example made of polydimethylsiloxane (PDMS) and can be prepared for example by soft lithography. An emulsion of the aqueous dispersion of particles in an oily continuous phase can be prepared inside the device by pumping the aqueous dispersed phase and the oily continuous phase according to a defined ratio, thus forming an emulsion by mixing the two phases. Alternatively, an oil-in-water emulsion can be used if the particle dispersion is an oily dispersion and the continuous phase is an aqueous phase. The continuous oily phase comprises for example an organic solvent, a silicone oil or a fluorinated oil. According to the invention, the term “oil” designates an organic phase (for example an organic solvent) immiscible with water. Organic solvents include hydrocarbons, such as heptane, hexane, toluene, xylene as well as alcohols, such as methanol, ethanol, propanol, etc.

Step 1) can also be carried out not from a dispersion comprising first particles (a) comprising a polymer and second particles (b) comprising a metal oxide or a metal oxide precursor, but from a dispersion comprising particles (a) comprising a polymer in a sol-gel matrix of metal oxide or its precursor (b).

Step 2: the droplets are dried so as to remove the solvent in order to provide dry spheres in the form of a matrix of the second particles (b) or of the sol-gel matrix (b) within which there are first particles (a). There is indeed a self-assembly between the first particles (a) and the second particles (b) or the sol-gel matrix (b) to form spheres having a matrix based on metal oxide or metal oxide precursor in which the polymer particles (a) are embedded. The spheres obtained are recovered, for example by filtration or centrifugation.

The drying is carried out according to conventional techniques, for example by microwave irradiation, in a thermal oven, under vacuum, in the presence of a dehydrating/absorbing agent or a mixture of these techniques.

Steps 1) and 2) can be carried out simultaneously by atomization. In certain embodiments of the spray drying techniques, the dispersion of particles (first particles (a) comprising a polymer and second particles (b) comprising a metal oxide or a metal oxide precursor or first particles (a) comprising a polymer in a sol-gel matrix of metal oxide or its precursor (b)) is fed (for example pumped) into an atomizing nozzle with a compressed gas inlet. Feed is pumped through the atomizing nozzle to form liquid droplets. The droplets are surrounded by a preheated gas in the evaporation chamber, resulting in the evaporation of the solvent to produce solid particles in the form of spheres (matrix of the second particles (b) or the sol-gel matrix (b) within which there are first particles (a)). The dried particles T1 are transported by the drying gas through the cyclone and deposited in the collection chamber. Usable gases include nitrogen and/or air.

In one embodiment of the spray drying process, the feed liquid contains an aqueous or oily phase in which the particles are dispersed (first particles (a) comprising a polymer and second particles (b) comprising a metal oxide or a metal oxide precursor or sol-gel matrix of metal oxide or its precursor (b)). Spray drying techniques include inkjet spray drying methods. Vibrating nozzles are commercially available from BÜCHI and include, for example, a syringe pump and a pulse unit.

Step 3: The dry spheres are calcined and optionally sintered. During this step, the metal oxide spheres or the sol-gel matrix densify and form a stable matrix around the polymer particles (a) and the polymer particles are removed by calcination (at a temperature ranging from 200-1200°C for a period ranging from 0.1 hour to 10 hours, advantageously at a temperature ranging from 300-800°C for a period ranging from 1 to 8 hours).

The calcination is carried out according to one embodiment at temperatures ranging from 200°C to 1200°C. According to one embodiment, the calcination temperature is at least 200°C, preferably at least 500°C, even more preferably at least 1000°C. Alternatively the calcination temperature ranges from 300°C to 800°C. The calcination is carried out for an appropriate period, for example ranging from 0.1 hour to about 10 hours, preferably from 1 hour to 8 hours. In certain embodiments, the calcination is carried out for at least 0.1 hour, for at least 1 hour, for at least 5 hours or for at least 8 hours. The first particles of polymer (a) therefore served as templates for the formation of the pores in the spheres according to the invention. The polymer particles (a) define an interstitial space. Calcination results in shrinkage of the polymer, thus providing a metal oxide sphere with high porosity or large interstitial volume (inverse structure). The porous metal oxide spheres are advantageously sintered, leading to a continuous, consolidated, thermally and mechanically stable solid structure.

The first polymer particles (a) that can be used in the process as a template are nanoparticles. They are also spherical, monodispersed and have a diameter D ₅ o measured by dynamic light scattering (DLS) measurement or by scanning electron microscopy (SEM), preferably by dynamic light scattering (DLS) measurement ranging from 50 nm to approximately 800 nm, advantageously from 50 nm to 500 nm.

We do not mean diameter D ₅₀ , the median diameter, meaning that half of the population is below and the other half is above.

Advantageously, the polymer nanoparticles (a) have a diameter D ₅ o measured by dynamic light scattering measurement

(DLS) of 50nm, 75nm, 100nm, 130nm, 160nm, 190nm, 210nm, 240nm, 270nm, 300nm, 330nm, 360nm, 390nm, 410nm, 440nm, 470nm, 500nm, 530nm, 560nm, 590nm, 620nm, 650nm, 680nm, 710nm, 740nm, 770nm or 800nm.

Preferably, the polymer is selected from the group consisting of poly(meth)acrylic acid, poly(meth)acrylates, polystyrenes, polyacrylamides, polyvinyl alcohol, polyvinyl acetate, polyesters, polyurethanes, polyethylene, polypropylene, polylactic acid, polyacrylonitrile, polyvinyl ethers, as well as their derivatives and their salts, their copolymers and their combinations. For example, the polymer is selected from the group consisting of polymethyl methacrylate, polyethyl methacrylate, poly(n-butyl methacrylate), polystyrene, poly(chloro-styrene), poly(alpha-methylstyrene), poly(N-methylolacrylamide) styrene/methyl methacrylate copolymer, polyalkylated acrylate, polyhydroxy acrylate, polyamino acrylate, polycyanoacrylate, polyfluorinated acrylate, poly(N-methylolacrylamide), polyacrylic acid rylic acid, polymethacrylic acid, methyl methacrylate/ethyl acrylate/acrylic acid copolymer, styrene/methyl methacrylate/acrylic acid copolymer, polyvinyl acetate, polyvinylpyrrolidone, polyvinylcaprolactone, polyvinylcaprolactam, a copolymer of methyl methacrylate and [2-(methacryloyloxy)ethyl]trimethylammonium chloride, as well as their derivatives and their salts, their copolymers and their combinations. Preferably, the polymer is chosen from the group consisting of polystyrenes, for example a copolymer of polystyrene/acrylic acid, polystyrene/poly(ethylene glycol) methacrylate or polystyrene/styrene sulphonate.

The spheres according to the invention can contain uniform pore diameters, due to the use of spherical and monodispersed polymer particles (a).

The second particles (b) or the sol-gel matrix comprising a metal oxide or a metal oxide precursor that can be used in the process according to the invention can be obtained by the sol-gel technique.

Advantageously, the second particles (b) which can be used in the process are nanoparticles. They have, for example, a diameter D ₅₀ measured by scanning electron microscopy (SEM) or by dynamic light scattering (DLS) measurement, preferably by scanning electron microscopy (SEM) ranging from 1 nm to approximately 120 nm.

Advantageously, the nanoparticles comprising a metal oxide or a metal oxide precursor (b) have a diameter D ₅₀ measured by scanning electron microscopy (SEM) of 1 nm, 5 nm, 10 11 0nm, 115nm, or 120nm.

These nanoparticles (b) can be spherical or non-spherical.

The second particles (b) or the sol-gel matrix can be made of metal oxide or a metal oxide precursor, in particular of silica, titanium, alumina, zirconia, cerium, iron oxides, zinc oxide, indium oxide, tin oxide, chromium oxide, and combinations thereof; in tetraethyl orthosilicate (TEOS) or tetramethyl orthosilicate (TMOS) as precursor of silica oxide, in titanium propoxide as precursor of titanium oxide, or in zirconium acetate as precursor of zirconium oxide.

In an advantageous embodiment, the first polymer nanospheres (a) have a positively charged surface and the second particles of metal oxide or of its precursor (b) or the sol-gel matrix (b) have a negatively charged surface.

In another advantageous embodiment, the first polymer nanospheres (a) have a negatively charged surface and the second particles of metal oxide or of its precursor (b) or the sol-gel matrix (b) have a positively charged surface.

It is the difference in charge on the surface which will cause the self-assembly of the particles between themselves or of the particles with the sol-gel matrix during the process of manufacturing the spheres.

The weight ratio (weight/weight) of nanoparticles or sol-gel matrix of metal oxide or precursor/polymer nanoparticles ranges for example from 1/10 to 10/1 or from 1/3 to 3/2. Advantageously, this ratio is: 1/10, 2/10, 3/10, 4/10, 5/10, 6/10, 7/10, 8/10, 9/10, 10/9, 10/8, 10/7, 10/6, 10/5, 10/4, 10/3, 10/2, or 10/1. In particular it is 1/3, 2/3, 1/1, or 3/2. The drying of the polymer/metal oxide droplets followed by the removal of the polymer in the process according to the invention makes it possible to obtain spheres having uniform cavities (pores). In general, in the methods described, each droplet forms a single microsphere or sphere. The pore diameters are dependent on the size of the polymer particles (a). A phenomenon of shrinkage or compaction may appear during the shrinkage of the polymer, producing pore sizes slightly smaller than the initial size of the polymer particles, for example ranging from 10% to 40% smaller than the size of the initial polymer particle. The pore diameter is as uniform as were the shape and size of the polymer particles (a).

In some embodiments, the porous sphere has a solid center or core and porosity toward the outer surface of the sphere.

In other rarer embodiments, the porous spheres have an empty center with a porosity which increases towards the interior of the spheres.

In certain embodiments, there is thus a gradient of porosity towards the center or towards the outside of the sphere but more frequently, the spheres have a homogeneous distribution of the porosity in the sphere.

In other preferred embodiments of the invention, the porosity is distributed uniformly throughout the volume of the spheres.

Templates of monodisperse polymer spheres (a) can result in metal oxide spheres having similar pores in diameter, once the polymer is removed.

Templates of polymer spheres (a) of two different sizes can result in metal oxide spheres having pores of two different diameters, once the polymer is removed.

Without being bound by theory, it is believed that most spheres exhibit a saturated color with reduced light scattering when the porosity and/or the diameter of the spheres and/or the diameter of the pores lie within certain ranges of values. These color properties are particularly important and can be adjusted according to the desired light scattering intensity on the skin, skin appendages and/or mucous membranes. In some embodiments it is preferable to have white spheres, in other embodiments it is preferable to have transparent spheres.

Preferably, most of the porous spheres have a structural color observable with the naked eye, in particular at a wavelength in the range 380nm - 800nm. One or more so-called light-absorbing agents may also be present in the spheres, thereby providing a more saturated observable color. Such absorbing agents are for example added during the physical mixing of the spheres or else are included in the droplets before drying. Thus, for example in this case the spheres according to the invention do not exhibit any observable color without a light-absorbing agent and exhibit an observable color when a light-absorbing agent is added.

The spheres then have the advantage of being able to be used as a tinting agent in cosmetic and/or dermatological compositions. The porous spheres according to the present invention can have a color dependent or not on the angle. By "an angle-dependent color" is meant an observed color that depends on the angle of the incident light or the angle between the observer and the observed color area. An angle-independent color means that the observed color does not depend substantively on the angle of the incident light or the angle between the observer and the observed color area. Spheres having an angle-dependent color can be obtained in particular by using monodispersed polymer nanospheres (a). They can also be obtained when the step of drying the liquid droplets making it possible to provide the model of the polymer spheres is carried out gently, thus allowing the polymer nanospheres to order themselves.

Spheres whose color is independent of the angle can be obtained when the step of drying the liquid droplets is carried out quickly, not allowing the polymer nanospheres to order themselves or when two sizes of polymer spheres (a) are used in the process (whether these polymer spheres (a) are of monodisperse or polydisperse bimodal distribution).

The angle dependence of color is independent of the polydispersity or the shape of the metal oxide particles (b).

Advantageously, the porous spheres according to the invention are themselves also monodispersed.

“Most of the spheres” means the population of the spheres. This can be an amount of > 0.1 mg, > 0.2 mg, > 0.3 mg, > 0.4 mg, > 0.5 mg, > 0.7 mg, > 1.0 mg, > 2.5 mg, > 5.0 mg, > 10.0 mg or > 25.0 mg. Most spheres may be devoid of other compounds.

The term "monodispersed" for the population of porous spheres or nanospheres of polymer or pores, particles or pores which have a homogeneous shape and a homogeneous diameter. The population of spheres and/or pores is thus said to be monodispersed when 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% of the number of particles or pores have a diameter of ± 7%, ± 6%, ± 5%, ± 4%, ± 3%, ± 2% or ± 1% compared to the average diameter of the population of spheres and/or pores or diameter D ₅₀ of polymer nanospheres, these diameters being measured by scanning electron microscopy (SEM).

Removal of the monodisperse population of polymer nanospheres (a) yields metal oxide spheres having a population of pores having an average diameter.

Thus the spheres according to the invention comprising a metal oxide are prepared by a method comprising the following steps: - Forming a liquid dispersion of polymer nanospheres and nanoparticles of a metal oxide or its precursor or of a sol-gel matrix;

- Form liquid droplets of the dispersion;

- Drying the liquid droplets of the spheres comprising the polymer nanospheres and the nanoparticles of a metal oxide or its precursor or the sol-gel matrix;

- Remove the polymer nanospheres from the model spheres to provide the porous metal oxide spheres according to the invention.

According to an advantageous mode, the liquid droplets are aqueous. Alternatively, the liquid droplets are oily.

According to a preferred mode, the method comprises a continuous phase and the mixing of the liquid dispersion with this continuous phase to form an emulsion containing the dispersed droplets of liquid dispersion. According to a particular mode, the continuous phase is oily and the mixture is carried out between the continuous oily phase and the aqueous liquid dispersion to form a water-in-oil emulsion containing aqueous droplets.

According to an alternative mode, the continuous phase is aqueous and the mixture is carried out between the continuous aqueous phase and the oily liquid dispersion to form an oil-in-water emulsion containing lipid droplets.

According to an advantageous mode, the method comprises the subsequent steps of collecting the droplets, drying the droplets and removing the polymer nanospheres from the model of spheres.

According to the present invention, the porous spheres according to the invention are used alone, in particular in powder form (100%), or in composition, in particular cosmetic, at a concentration ranging from 1x10 ³ to 100% by weight, and advantageously ranging from 1x10 ^-2 to 95%, preferably ranging from 0.01% to 80%, more preferably 0.05% up to 50%, preferably from 0.1% up to 30%, preferably up to 20%, more preferably up to 10%, and even more preferably from 0.5% to 5% by weight relative to the total weight of the composition.

The porous spheres according to the invention can be used alone, in particular in the form of a cosmetic active ingredient or in a composition intended to be in contact with the skin, the appendages and/or the cutaneous mucous membranes, such as for example a cosmetic composition, preferably intended for topical application.

The active ingredient and/or the cosmetic compositions containing the porous spheres according to the invention are preferentially intended for the care and/or the cosmetic treatment of the skin and/or the mucous membranes, including the scalp as well as the skin appendages, preferentially the hair.

In another embodiment, the spheres according to the invention can be incorporated into a cosmetic composition further comprising at least one cosmetically acceptable excipient.

Within the meaning of the present invention, the term “cosmetically acceptable” excipient is understood to mean a topically acceptable compound and/or solvent, that is to say not inducing an allergic response on contact with the skin, including the human scalp, and the skin appendages, non-toxic, non-unstable, or their equivalents, undue.

The cosmetic composition according to the invention may be in any galenic form conventionally used for topical application to the skin and/or mucous membranes, including the scalp, and skin appendages, such as liquid or solid forms or even in the form of liquid under pressure. They may in particular be formulated in the form of an aqueous or oily solution, in particular a lotion, a cream or an aqueous gel or an oily gel, in particular in a jar or in a tube, in particular a shower gel, a shampoo, a conditioner, a milk, an oil, an emulsion, a hydrogel, a microemulsion or a nanoemulsion, in particular oil-in-water or water-in-oil or multiple or silicone-based, a serum, a lotion, in particular in a glass or plastic bottle or in a metering bottle or in an aerosol or spray, an ampoule, a liquid or solid soap, a paste, an ointment, a mousse, a mask, a lacquer, a patch, an anhydrous product, preferably liquid, pasty or solid, for example in the form of a stick, in particular in stick or in powder form, preferably a cream, a serum or a lotion.

It may also be a make-up product or a make-up removal product. In particular, the cosmetic composition is chosen from the group consisting of a serum, a lotion, a cream, a shampoo, a conditioner, an oil, a milk, an ointment, a paste, a mousse, an emulsion, a hydrogel, a shower gel, a mask, a lacquer, a spray, a wax, even more preferably it is a cream, a serum or a lotion. It may also be a powder, in particular for make-up, a stick foundation, compositions for beard care, after shaving and/or depilation. According to an advantageous mode, the cosmetic composition according to the invention is at least slightly gelled and/or comprises an oily phase, preferably is of the oily composition or oil-in-water or water-in-oil emulsion or lotion type.

The compositions according to the invention may contain any suitable solvent and/or any suitable vehicle and/or any suitable excipient, optionally in combination with other compounds of interest.

Therefore, for these compositions, the excipient contains, for example, at least one compound chosen from the group consisting of preservatives, emollients, emulsifiers, surfactants, moisturizers, thickeners, conditioners, mattifying agents, stabilizers, antioxidants, texture agents, shine agents, film formers, solubilizers, pigments, dyes, perfumes and sunscreens. These excipients are preferably chosen from the group consisting of amino acids and their derivatives, polyglycerols, esters, polymers and cellulose derivatives, Lanolin derivatives, phospholipids, lactoferrins, lactoperoxidases, sucrose-based stabilizers, vitamins E and its derivatives, natural and synthetic waxes, vegetable oils, triglycerides, unsaponifiables, phytosterols, plant esters, silicones and derivatives thereof, protein hydrolysates, jojoba oil and derivatives thereof, lipo/water-soluble esters, betaines, aminoxides, plant extracts, sucrose esters, titanium dioxides, glycines, and parabens, and more preferably from the group consisting of butylene glycol, steareth-2, steareth-21, steareth-15 glycol aryl ether, cetearyl alcohol, phenoxyethanol, methylparaben, ethylparaben, propylparaben, butylparaben, butylene glycol, natural tocopherols, glycerin, dihydroxycetyl sodium phosphate, isopropyl hydroxycetyl ether, glycol stearate, triisononanoin, octyl cocoate, polyacrylamide, isoparaffin, laureth-7, a carbomer, propylene glycol, glycerol, bisabolol, a dimethicone, sodium hydroxide, PEG 30-dipolyhydroxysterate, capric/caprylic triglycerides, cetearyl octanoate, dibutyl adipate, grapeseed oil, jojoba oil, magnesium sulfate, EDTA, a cyclomethicone, x-gum anthan, citric acid, sodium lauryl sulphate, waxes and mineral oils, isostearyl isostearate, propylene glycol dipelargonate, propylene glycol isostearate, PEG 8, Beeswax, hydrogenated palm oil glycerides, hydrogenated palm oil glycerides, lanolin oil, sesame oil, cetyl lactate, lanolin alcohol, castor oil, titanium dioxide, lactose, sucrose, low density polyethylene, isotonic saline solution. Many cosmetically active ingredients are known by those skilled in the art to improve the appearance of the skin. A person skilled in the art knows how to formulate cosmetic or dermatological compositions to obtain the best effects. On the other hand the compounds described in the present invention can have a synergistic effect when they are combined with each other. These combinations are also covered by the present invention. The CTFA Cosmetic Ingredient Handbook, Second Edition (1992) describes various cosmetic and pharmaceutical ingredients commonly used in the cosmetic and pharmaceutical industry, which are particularly suitable for topical use. Examples of these classes of ingredients include, but are not limited to, the following compounds: abrasive, absorbents, compound for cosmetic purposes such as perfumes, pigments, dyes, essential oils, astringents, anti-acne agents, anti-flocculating agents, anti-foaming agents, anti-microbial agents (e.g. iodopropyl butylcarbamate), antioxidants, binders, biological additives, buffering agents, bulking agents, chelating agents, additives, biocidal agents, denaturants, thickeners, and vitamins, and derivatives or equivalents thereof, film-forming materials, polymers, opacifying agents, pH adjusters, reducing agents, depigmenting or lightening agents (for example: hydroquinone, kojic acid, ascorbic acid, magnesium ascorbyl phosphate, ascorbyl glucosamine), conditioning agents (for example: humectants).

In a particularly advantageous manner, the spheres according to the invention can be used, optionally in a cosmetic or pharmaceutical composition, preferably dermatological, as the sole agent for improving the appearance, in particular the unsightly manifestations and/or the comfort of the skin, appendages and/or mucous membranes, or in combination with other active agents having the same properties or complementary and conventional properties in cosmetic or dermatological compositions, such as those chosen from:

- moisturizing agents: one or more hydration-promoting agents such as a polysaccharide extracted from seeds of Cassia angustifoua marketed under the name Hyalurosmooth™ by the applicant, or an agent chosen from one of the combinations containing pullulan, sodium hyaluronate and sodium alginate marketed under the name PatcH20™ by the applicant or one or more of the compounds of the natural moisturizing factor or a natural extract of honey marketed by the applicant under the name Melhydran™ and/or a compound of the glucosyl glyceride family, in particular hexosyl glyceride, an extract of the pericarp of Litchi chinensis under the name Litchiderm™ by the applicant;

- an agent stimulating the synthesis of fibronectin, in particular an extract of maize, such an extract being in particular marketed by the applicant under the name Deliner™;

- an agent for protecting the fibroblast growth factor (FGF2) of the extracellular matrix against its degradation and/or its denaturation, in particular an extract of Hibiscus Abeimoscus as described in the patent application in the name of the applicant filed under the number FR0654316 and/or an agent for stimulating the growth of fibroblasts, for example a fermented soybean extract containing peptides, known under the name of Phytokine™ marketed by the applicant and also described in patent application EPI 119344 B1 (Laboratoires Expanscience), and preferably a combination of these two extracts;

- an agent stimulating the synthesis of laminin, in particular a malt extract modified by biotechnology, such an extract being in particular marketed by the applicant under the name Basaline™; and a lipid synthesis stimulating agent such as potato extract solarium tuberosum} modified by biotechnology marketed by the applicant under the name Lipidessence™;

- an agent stimulating the expression and/or activity of Hyaluronan synthase 2 (HAS2) such as the plant extracts described in patent application FR2 893 252 Al and in particular an aqueous extract of Galangal (Alpinia galanga marketed under the name Hyalufix™ by the applicant;

- an agent stimulating the synthesis of lysyl oxidase like (LOXL) such as those described in patent application FR2855968, and in particular a dill extract marketed under the name Lys'lastine™ by the applicant;

- one or more anti-pollution agents such as an extract of A' rgania spinosa leaves marketed under the name Arganyl™ by the applicant or an extract of seeds of Moringa oleifera marketed under the name Purisoft™ by the applicant or else an extract of Eperua falcata root marketed under the name Eperuline™ by the applicant;

- an agent stimulating the synthesis of intracellular ATP, in particular an extract of Laminaria digitata seaweed;

- an agent with overall anti-ageing action, in particular anti-pigment spots, in particular niacinamide or vitamin B3;

- an antibacterial agent and/or sebum regulator, and/or sebum absorber such as retinoids, sarcosine, zinc salts, in particular zinc gluconate, zinc salicylate, azelaic acid, and/or their derivatives and mixtures, an extract of Orthosiphon stamineus marketed under the name MAT XS™ Bright by the applicant, an extract of Bixa Orellana marketed under the name Bix'Activ ™ by the applicant, the antibacterial extracts described in patent application FR2863893, and in particular an extract of Boldo, in particular that marketed under the name Betapur™ by the applicant, or talc, and any of their mixtures. According to a preferred mode of the invention, the spheres are formulated with a make-up base conventionally called a "primer", which may contain pigments and/or mica.

According to an alternative mode of the invention, the spheres are formulated in a cosmetic composition in combination with a cosmetic active ingredient as listed above, preferably chosen from agents modifying the color of the skin and/or the radiance of the skin such as bleaching agents, anti-aging agents, in particular those acting on photo-induced aging, moisturizers, anti-pollution, in particular antioxidant, soothing, regulators and/or sebum absorbers, matifying, prebiotic, cosmetic active acting on the imperfections of the surface and/or relief and/or color of the skin, antibacterial, and/or agent for sensitive skin.

Even more preferentially, the spheres according to the invention are in a cosmetic composition containing at least one ingredient chosen from makeup pigments, mica, a moisturizing agent, an anti-aging agent and/or an agent acting on imperfections in relief, color and/or surface of the skin and/or mixtures thereof, even more preferably a moisturizing agent and/or an anti-aging agent.

Advantageously, the cosmetic composition according to the invention contains at least one cosmetic excipient and/or one cosmetic pigment and/or colorant and/or one UV filter and/or one anti-blue light filter and/or one cosmetic active ingredient, preferably chosen from agents modifying the color of the skin and/or the radiance of the skin such as bleaching agents, anti-aging agents, in particular those acting on photo-induced aging, moisturizers, anti-pollution, in particular antioxidant, soothing, regulators and/or absorbers of sebum, matifying agent, prebiotic, cosmetic active agent acting on imperfections of the surface and/or the relief and/or the color of the skin, antibacterial, and/or agent for sensitive skin. The use of porous spheres according to the present invention is particularly advantageous in that it allows an immediately effective and lasting action on any type of skin including the scalp, on the skin appendages, preferably the hair and on the mucous membranes, in particular skin showing unsightly manifestations or signs of discomfort.

Preferably, the porous spheres according to the invention, preferably in the form of a cosmetic composition according to the invention, are applied to at least one area of the body where there are unsightly and/or uncomfortable manifestations, this or these areas preferably being a surface of the body chosen from the skin of the face, including the forehead, the cheeks, the nose, the temples, the so-called "T" area (forehead, nose and chin), under the eyes, the peri-orbital area, in particular dark circles , the chin, the scalp, the neck, the back, the shoulders, the arms, the forearms, the thorax, the hands, the hair, the beard, the eyelashes, the eyebrows, the bust, in particular the neckline, the stomach and/or the armpits, the legs, the feet, the hands, the neck, the thighs, the hips, the buttocks, the waist, the torso, the outline of the lips, the hair, the hair and/or the mucous membrane ocular, labial and/or buccal, preferentially the skin of the face, the hands, the neckline.

The present invention thus also relates to a cosmetic care process, advantageously non-therapeutic, for improving the appearance and/or the comfort of the skin, of the skin appendages, in particular the hair, and/or of the mucous membranes, comprising the topical application on at least one area of skin and/or of mucous membranes and/or of skin appendages, in particular the hair, of porous spheres according to the invention, preferably on at least one surface chosen from a surface of the body chosen from the skin of the face, including the forehead, the cheeks, nose, temples, the so-called "T" area (forehead, nose and chin), under the eyes, the peri-orbital area, in particular dark circles, chin, scalp, neck, back, shoulders, arms, forearms, thorax, hands, hair, beard, eyelashes, eyebrows, bust, in particular the neckline, stomach and/or armpits, legs, feet, hands, neck, thighs, hips, buttocks, waist, torso, around the lips, hair, hair and/or the ocular, labial and/or mucous membrane mouth, preferably the skin of the face, hands, décolleté.

The spheres according to the invention are particularly suitable for their uses on any type of skin, mucous membranes and/or appendages, in particular Caucasian, Asian, African as well as on any type of skin, in particular sensitive skin, skin with atopic tendency, oily skin. They are particularly suitable for masking the first unsightly signs of aging, in particular the first expression wrinkles and/or for mature skin, that is to say men or women aged at least 50, in particular menopausal women.

The cosmetic compositions according to the invention are preferably of the leave-in type.

Advantageously, the porous spheres according to the invention, preferentially in the form of a composition intended for topical application, preferentially cosmetic according to the invention, are used in regular topical application and preferentially at least once a day, advantageously twice a day. Preferably, the cosmetic composition is applied to the skin.

The spheres can be used in powder but also in the form of a cosmetic ingredient formulated in liquid form. For their formulation as cosmetic ingredient, the spheres are then preferentially placed in suspension in glycerine and/or in another solvent, in particular polar solvent such as water, alcohols, in particular propanediol, glycols in particular butylene glycol, propylene glycol, polyols or a mixture of these, preferentially a mixture hydroglycolic, more preferably containing a glycol chosen from butylene glycol, propylene glycol, caprylyl glycol, hexylene glycol and mixtures thereof. In a particularly advantageous manner, the spheres according to the invention are suspended in an aqueous solution containing glycerin, hexylene glycol, caprylyl glycol or a mixture thereof.

Advantageously, the invention also relates to a cosmetic treatment method for improving the appearance and/or the comfort of the skin, of the skin appendages, in particular the hair, and/or of the mucous membranes, of an individual who needs/wants it, comprising the steps:

- The identification on the individual of an area of skin and/or mucous membranes and/or cutaneous appendages, the appearance and/or comfort of which must be improved and/or presenting unsightly manifestations to be concealed, and

- Topical application to this area of skin and/or mucous membranes and/or skin appendages of a cosmetic composition containing the spheres according to the invention in an amount effective to improve the appearance and/or comfort of this area of skin and/or mucous membranes and/or skin appendages, preferably hair, namely advantageously in a content of spheres comprised between 1x10 ³ to 100% by weight, and advantageously ranging from 1x10 ^-2 to 9 5%, preferably ranging from 0.01% to 80%, more preferably from 0.05% up to 50%, preferably from 0.1% up to 30%, preferably up to 20%, even more preferably up to 10%, and even more preferably from 0.5% to 5% by weight relative to the total weight of the composition.

The spheres according to the invention can also be used to improve the comfort of the skin, the mucous membranes and/or the cutaneous appendages presenting a pathology.

The skin, the mucous membranes and/or the cutaneous appendages are preferentially altered, in particular in the context of a pathology selected from the group consisting of reactive, inflammatory, atopic skin, hyperpigmented, hypopigmented, hyperseborrheic skin, in particular skin affected by vitiligo, melanoma, rosacea, telangiectasia, acne, rosacea, urticaria, psoriasis, herpes, impetigo, ecthyma, erysipelas, and/or presenting sores and/or or scars including acne, pimples, boils, varicose veins, melasma, folliculitis, abscesses, any combination thereof.

In a preferred embodiment of the invention, the spheres according to the invention are in the form of a pharmaceutical composition further comprising a pharmaceutically acceptable excipient and are present in the pharmaceutical composition in a sphere content of between 1x10 ³ to 100% by weight, and advantageously ranging from 1x10 ^-2 to 95%, preferably ranging from 0.01% to 80%, more preferably from 0.05% up to 5 0%, preferably from 0.1% up to 30%, preferably up to 20%, more preferably up to 10%, and even more preferably from 0.5% to 5% by weight relative to the total weight of the composition.

Other aims, characteristics and advantages of the invention will appear clearly to those skilled in the art following reading of the explanatory description which refers to examples which are given solely by way of illustration and which cannot in any way limit the scope of the invention.

The examples form an integral part of the present invention and any feature appearing new with respect to any state of the prior art from the description taken as a whole, including the examples, forms an integral part of the invention in its function and in its generality. Thus, each example is general in scope. On the other hand, in the examples, all the percentages are given by weight, unless otherwise indicated, the temperature is expressed in degrees Celsius unless otherwise stated, and pressure is atmospheric pressure unless otherwise stated.

Brief description of the drawings

FIG. IA represents a cross-sectional view of a sphere according to the invention with closed porosity and FIG. IB a view of a porous sphere of the prior art, in particular according to applications WO2020/183108 and WO2020/182936.

FIG. 2 shows an SEM image of a porous sphere according to the invention obtained according to example 1 (top image) as well as a cross section of this sphere (bottom image).

FIG. 3 shows an SEM image of a porous sphere according to the invention obtained according to example 2 (top image) as well as a cross section of this sphere (bottom image).

Figure 4 shows an SEM image of a porous sphere according to the invention obtained according to example 7.

EXAMPLES

Example 1: Porous silica spheres with closed porosity according to the invention

An aqueous dispersion of positively charged poly(meth)acrylate nanoparticles with a diameter D ₅₀ of 210nm measured by dynamic light scattering (DLS) was diluted to 1% (w/w) with deionized water and 3% (w/w) of negatively charged silica nanoparticles having a diameter D ₅₀ of 7nm measured by SEM were added. The mixture was sonicated for 30 seconds to prevent agglomeration. The dispersion loaded with nanoparticles and the oily phase (continuous oily phase containing 2% (w/w) of polyethylene-glycol-co-perfluoro polyester surfactant in fluorinated oil) were each injected into a microfluidic device having a junction making it possible to obtain a droplet size of 50 μm via syringes associated with pumps. The whole is left to equilibrium until monodisperse droplets are produced. These are then collected in a tank.

The collected droplets are then dried in an oven at 50° C. for 4 hours to provide dry spheres (dry powder). These spheres are then calcined by placing them on a silicone plate, and heating them from room temperature to 500°C for a period of 4 hours, then maintaining the temperature at 500°C for 2 hours. The spheres are left to cool at room temperature for 4 hours. The porous monodispersed silica oxide spheres with closed porosity thus obtained have an average diameter of 15 microns measured by scanning electron microscopy (SEM) and an average porosity measured by mercury porosimetry of 0.55.

An SEM image of one of the obtained spheres (top image) together with its cross-section (bottom image) is presented in Fig. 2. The cross-section clearly shows the interior of the sphere structure comprising a relatively monodisperse and ordered closed pore network. 97% by volume of the pores of these spheres are closed pores.

According to an alternative mode, Example 1 can be repeated by carrying out the drying step by microwave irradiation, by drying under vacuum and/or in the presence of a dehydrating agent.

Example 2: Porous silica spheres with closed porosity according to the invention obtained by atomization

An aqueous suspension of positively charged spherical nanoparticles of methyl methacrylate copolymer and 2-(methacryloyloxy)ethyl]trimethylammonium chloride having a diameter D ₅₀ measured by dynamic light scattering (DLS) measurement of 210 nm and negatively charged silica nanoparticles (average diameter measured by scanning electron microscopy (SEM) of 7 nm) was prepared. The aqueous suspension contains a content of 2.25% by weight of copolymer nanoparticles and a content of 0.75% by weight of silica nanoparticles, relative to the total weight of the suspension (ratio by weight of copolymer nanoparticles: silica nanoparticles=3:1).

The aqueous suspension is dried by atomization under a nitrogen atmosphere (inlet temperature: 100° C., outlet temperature: 45° C., feed rate: 10 mL/min, atomization gas pressure 40 mm) using a BÜCHI laboratory size atomizer.

The microspheres obtained are then calcined in a muffle furnace, in order to sinter and densify the silica nanoparticles and to remove the polymer, by placing them on a silicone plate and by carrying out a temperature rise from ambient temperature to 550° C. for a period of 5 hours, then by maintaining the temperature at 550° C. for 2 hours, then finally by lowering the temperature from 550° C. to ambient temperature for a period of 3 hours. The porous microspheres with closed porosity of monodisperse SiCh thus obtained have an average diameter of 2.9 μm (with standard deviation of 1.5 μm) measured by scanning electron microscopy (SEM), an average pore diameter of 165 nm measured by scanning electron microscopy (SEM) and an average porosity measured by mercury porosimetry of 0.55. 94% by volume of the pores of these spheres are closed pores.

Another sphere was obtained having an average diameter of 2.9 μm and an average pore diameter of 210 nm was obtained according to the same protocol by simply changing the content of nanoparticles: The aqueous suspension used contained a content of 2.25% by weight of copolymer nanoparticles and a content of 0.75% by weight of silica nanoparticles, relative to the total weight of the suspension (ratio by weight copolymer nanoparticles: silica nanoparticles = 3:1 ) An SEM image of one of the spheres obtained (top image) as well as its cross section (bottom image) is presented in Figure 3. The cross section clearly shows the interior of the structure of the sphere comprising a network of relatively monodisperse and ordered closed pores. 96% by volume of the pores of these spheres are closed pores.

Example 3: Porous silica spheres with closed porosity according to the invention obtained by atomization

An aqueous suspension of positively charged spherical nanoparticles of methyl methacrylate copolymer and 2-(methacryloyloxy)ethyl]trimethylammonium chloride having a diameter D _5o measured by dynamic light scattering (DLS) measurement of 210 nm and negatively charged silica nanoparticles (mean diameter measured by scanning electron microscopy (SEM) of 7 nm) was prepared. The aqueous suspension contains a content of 7.5% by weight of copolymer nanoparticles and a content of 2.5% by weight of silica nanoparticles, relative to the total weight of the suspension (ratio by weight copolymer nanoparticles: silica nanoparticles = 3:1).

The aqueous suspension is dried by atomization under a nitrogen atmosphere (inlet temperature: 100° C., outlet temperature: 45° C., feed rate: 10 mL/min, atomization gas pressure 40 mm) using a BÜCHI laboratory size atomizer.

The microspheres obtained are then calcined in a muffle furnace, in order to sinter and densify the silica nanoparticles and to remove the polymer, by placing them on a silicone plate and by carrying out a temperature rise from ambient temperature to 550° C. for a period of 5 hours, then by maintaining the temperature at 550° C. for 2 hours, then finally by lowering the temperature from 550° C. to ambient temperature for a period of 3 hours. The porous microspheres with closed porosity of monodisperse SiCh thus obtained have an average diameter of 7.6 μm (with standard deviation of 3.5 μm) measured by scanning electron microscopy (SEM), an average pore diameter of 165 nm measured by scanning electron microscopy (SEM) and a average porosity measured by mercury porosimetry of 0.55. At least 90% by volume of the pores of these spheres are closed pores.

Example 4: Porous silica spheres with closed porosity according to the invention containing carbon black

The product of Example 1 was physically mixed with an aqueous dispersion of carbon black or carbon black powder at different weight contents. The porous spheres obtained contained carbon black in a content of 0.5%, 1%, 2%, 3%, 4% and 5% by weight, relative to the total weight of the particles.

Example 5: Variation of sphere colors

A quantity of 0.5 mg of porous spheres of Example 1 are placed in a 20 ml clear glass bottle having a surface area at the bottom of 6 cm ² . The blue color is observed with the naked eye.

A sample of porous spheres is prepared according to example 1 with the exception of the weight ratio of the polymer/silica which is 2/1. The sample prepared has a green color observable with the naked eye.

Example 6: porous titanium spheres

An aqueous suspension of negatively charged spherical polystyrene nanoparticles having a diameter D ₅₀ measured by dynamic light scattering (DLS) measurement of 197 nm and positively charged titanium nanoparticles (average diameter measured by scanning electron microscopy (SEM) of 15 nm) was prepared. The aqueous suspension contains a content of 1.8% by weight of polymer nanoparticles and a content of 1.2% by weight of titanium nanoparticles, relative to the total weight of the suspension (ratio by weight polymer nanoparticles: titanium nanoparticles = 3:2).

The aqueous suspension is dried by atomization under a nitrogen atmosphere (inlet temperature: 100° C., outlet temperature: 45° C., feed rate: 10 mL/min, atomization gas pressure 55 mm) using a BÜCHI laboratory size atomizer. The microspheres obtained are then calcined in a muffle furnace, in order to sinter and densify the titanium nanoparticles and to remove the polymer, by placing them on a silicone plate and by raising the temperature from ambient temperature to 300°C for a period of 4 hours, then by maintaining the temperature at 300°C for 6 hours, then by raising the temperature to 550°C for a period of 2 hours, then by maintaining the temperature at 550°C for 2 hours, then finally lowering the temperature from 550°C to room temperature for a period of 4 hours. The porous microspheres with closed porosity of TiCh thus obtained have an average diameter of 2.8 μm measured by scanning electron microscopy (SEM) with a standard deviation of 1.5 μm, an average pore diameter of 142 nm with a standard deviation of 15 nm measured by scanning electron microscopy (SEM) and an average porosity measured by mercury porosimetry of 0.55. 95% by volume of the pores of these spheres are closed pores.

Example 7: Porous silica spheres with closed porosity according to the invention obtained by sol-gel process

An aqueous suspension of positively charged spherical nanoparticles of methyl methacrylate copolymer and 2-(methacryloyloxy)ethyl]trimethylammonium chloride having a measured dynamic light scattering (DLS) diameter D ₅ o of 254 nm and tetramethyl orthosilicate (TMOS) silica precursor was mixed at a pH in the range 2-5. The aqueous suspension contains a content of 1.8% by weight of copolymer nanoparticles and a content of 3.6% by weight of TMOS, relative to the total weight of the suspension (ratio by weight copolymer nanoparticles:TMOS=1:3).

The aqueous suspension is dried by atomization under a nitrogen atmosphere (inlet temperature: 100° C., outlet temperature: 45° C., feed rate: 10mL/min, atomizing gas pressure 40 mm) using a BÜCHI lab-size atomizer.

The microspheres obtained are then calcined in a muffle furnace, in order to convert the silica precursor into silica nanoparticles, to densify the silica and to remove the polymer, by placing them on a silicone plate and carrying out a temperature rise from room temperature to 200°C for a period of 3 hours, then maintaining the temperature at 200°C for 2 hours, then carrying out a temperature rise to 550°C for a period of 2 hours, then maintaining the temperature at 550°C for 2 hours, then finally lowering the temperature from 550°C to room temperature for a period of 3 hours. The porous microspheres with closed porosity of SiO2 thus obtained have an average diameter of 3 μm with a standard deviation of 1.7 μm measured by scanning electron microscopy (SEM), an average pore diameter of 212 nm with a standard deviation of 15 nm measured by scanning electron microscopy (SEM) and an average porosity measured by mercury porosimetry comprised between 0.5 and 0.065. 90% by volume of the pores of these spheres are closed pores.

An SEM image of one of the obtained spheres is shown in Figure 4.

Example 8: Porous silica spheres with closed porosity according to the invention with pores of disordered sizes

An aqueous suspension of positively charged spherical nanoparticles of methyl methacrylate copolymer and 2-(methacryloyloxy)ethyl]trimethylammonium chloride of two different sizes (diameter D ₅₀ measured by dynamic light scattering (DLS) measurement of 254 nm and 142 nm) and negatively charged silica nanoparticles (diameter D ₅₀ measured by dynamic light scattering (DLS) measurement of 7 nm) has been prepared. The aqueous suspension contains a content of 1.8% by weight in total of nanoparticles of copolymer (0.9% of each size) and a content of 0.6% by weight of silica nanoparticles, relative to the total weight of the suspension (ratio by weight copolymer nanoparticles: silica nanoparticles = 3:1).

The aqueous suspension is dried by atomization under a nitrogen atmosphere (inlet temperature: 100° C., outlet temperature: 45° C., feed rate: 10 mL/min, atomization gas pressure 40 mm) using a BÜCHI laboratory size atomizer.

The microspheres obtained are then calcined in a muffle furnace, in order to sinter and densify the silica nanoparticles and to remove the polymer, by placing them on a silicone plate and by carrying out a temperature rise from ambient temperature to 550° C. for a period of 6 hours, then by maintaining the temperature at 550° C. for 2 hours, then finally by lowering the temperature from 550° C. to ambient temperature for a period of 4 hours. The porous microspheres with closed porosity of SiCh thus obtained have an average diameter of 2 μm measured by scanning electron microscopy (SEM). They have a bimodal distribution with an average pore diameter estimated at 165 nm. 93% by volume of the pores of these spheres are closed pores.

A quantity of 0.5 mg of porous spheres thus obtained are placed in a 20 ml clear glass bottle having a surface area at the bottom of 6 cm ² . The angle-independent blue color is observed with the naked eye.

Example 9: evaluation of the improvement in the “soft focus” property by a cosmetic composition according to the invention

The spheres obtained according to Example 3 with an average diameter measured by scanning electron microscopy (SEM) of 7.6 μm, an average pore diameter measured by scanning electron microscopy (SEM) of 165 nm and a porosity of 0.55 (Ex 3) were incorporated into the oil-based formulation indicated in Example 10 below in a content of 1.5% by weight relative to the total weight of the formulation. The spheres obtained according to Example 2 with an average diameter D ₅₀ measured by scanning electron microscopy (SEM) of 2.9 μm, an average pore diameter measured by scanning electron microscopy (SEM) of 165 nm and a porosity of 0.55 (Ex 2) were incorporated into the oil-based formulation indicated in Example 10 below in a content of 1% by weight relative to the total weight of the formulation.

The optical properties of transmittance and diffusion (haze) of these formulations were measured and compared with those measured for porous spheres described in application WO2020183108 (open porosity) whose % of closed pores by volume is less than 5%:

- spheres with an average diameter measured by scanning electron microscopy (SEM) of 6.7 μm, an average pore diameter measured by scanning electron microscopy (SEM) of 153 nm and a porosity of 0.55 (Ex Comp 3) incorporated into the oil-based formulation indicated in Example 10 below in a content of 1.5% by weight relative to the total weight of the formulation.

- spheres with an average diameter measured by scanning electron microscopy (SEM) of 2.6 μm, an average pore diameter measured by scanning electron microscopy (SEM) of 153 nm and a porosity of 0.55 (Ex Comp 2) incorporated into the oil-based formulation indicated in Example 10 below in a content of 1% by weight relative to the total weight of the formulation, with vigorous stirring.

The measurements were carried out after having put 3 ml of formulation on a glass plate (3 samples per formulation) and left to dry for at least 1 hour. Measurements of total transmittance and scattering (Haze) were performed by the BYK-Gardner haze-gard apparatus (BYK-Gardner GmbH Germany).

The results are collated in Table 1 below.

[Table 1]

The spheres according to the invention have a higher total transmittance and haze value than those of the prior art, thus making it possible to improve their blurring/masking/soft focus property. Indeed, particles with a "soft focus" effect must show properties of:

- high total transmittance to give a natural appearance and

- diffusion ("haze") to its maximum to form a translucent and uniform light distribution.

Example 10: Oil-Based Formulation Used in Example 8

It is an emulsion. Its composition is shown in Table 2 below.

[Table 2]

The emulsion is prepared by the usual methods in the field well known to those skilled in the art, by separately heating phases A and B to 75-80° C. with stirring. Phase C is added to phase A with stirring and when the phases are homogeneous, phase B is added to phase AC with stirring until completely dispersed. The mixture is left to cool with gentle stirring to ambient temperature and the compounds of the additional phases are added, one after the other. The whole is homogenized for 2 min. The pH is adjusted to 5.2.

Example 10 Cosmetic Compositions According to the Invention The porous spheres used are those obtained in Examples 1 to 7 in powder form.

Example lOaj: Fluid emulsion for the face

[Table 3]

The emulsion is prepared by the usual methods in the field well known to those skilled in the art, by introducing phase B into phase A and stirring until completely dispersed. The mixture is heated to 75-80°C as is phase C separately. Then phase C is added to the mixture with stirring. The mixture is left to cool with gentle stirring to ambient temperature and the compounds of phases E and F are added, one after the other. The whole is homogenized for 2 min. The pH is adjusted to 5.2.

Example 10b): Face Cream [Table 4]

The cream is prepared by the usual methods in the field well known to those skilled in the art, by mixing phases A and B previously heated to 75° C., then by adding phases C and D by mixing and adjusting the composition with phase E at a pH of 6.2 and at a viscosity of 15,000 mPas (measured with a Brookfield apparatus (RVT; 23° C., spindle TC; 20 revolutions per min). Example 10c ¹ ): shampoo

[Table 5]

The shampoo is prepared by the usual methods in the field well known to those skilled in the art, by mixing the 4 phases and adjusting the composition to a pH of 5.2 and to a viscosity of 2200 mPas (measured with a Brookfield device (RVT; 23° C., spindle 5; 50 revolutions per min).

Claims

Claims 1. Non-therapeutic cosmetic use of porous spheres with closed porosity comprising a metal oxide to improve the appearance and/or the comfort of the skin, of the skin appendages, in particular the hair, and/or of the mucous membranes. 2. Use according to claim 1, characterized in that at least 90% by volume of the pores of the spheres are closed pores, advantageously at least 95% by volume of the pores are closed pores. 3. Use according to any one of claims 1 or 2, characterized in that the spheres have an average diameter measured by scanning electron microscopy (SEM) ranging from 1 μm to 100 μm and/or an average porosity ranging from >0.10 to 0.80 and/or an average pore diameter measured by scanning electron microscopy (SEM) ranging from 50 nm to 800 nm, advantageously from 50 nm to 500 nm Mr. 4. Use according to one of the preceding claims, characterized in that the spheres have an average diameter measured by scanning electron microscopy (SEM) ranging from 1 μm to 100 μm and an average porosity ranging from >0.10 to 0.80 and an average pore diameter measured by scanning electron microscopy (SEM) ranging from 50 nm to 800 nm. 5. Use according to one of the preceding claims, characterized in that the metal oxide is silicon oxide, titanium, aluminum, zirconium, cerium, iron, zinc oxide, indium oxide, tin oxide, chromium oxide, mixed metal oxide and combinations thereof. 6. Use according to the preceding claim, characterized in that the metal oxide is chosen from the group consisting of SiO ₂ , TiO ₂ , ZnO and their mixtures, advantageously it is SiO ₂ . 7. Use according to one of the preceding claims, characterized in that the porous spheres comprise from 60% by weight to 99.9% by weight of metal oxide and from 0.1% by weight to 40% by weight of light-absorbing agents, by total weight of the spheres, advantageously from 0.1% by weight to 40% by weight of carbon black. 8. Use according to one of the preceding claims, characterized in that the spheres have an average diameter measured by scanning electron microscopy (SEM) ranging from 1 μm to 75 μm and an average porosity ranging from 0.45 to 0.70. 9. Use according to one of the preceding claims, characterized in that the spheres have an average diameter measured by scanning electron microscopy (SEM) ranging from 2.5 μm to 8 μm, an average porosity ranging from 0.45 to 0.70 and an average pore diameter measured by scanning electron microscopy (SEM) ranging from 100 nm to 200 nm. 10. Use according to one of the preceding claims for reducing the visibility of unsightly manifestations of the skin, skin appendages and/or mucous membranes, in particular irregularities in the relief and/or texture of the skin, mucous membranes and/or skin appendages, and/or irregularities in the color of the skin and/or mucous membranes. 11. Use according to one of the preceding claims, in which the spheres are present in a cosmetic composition, at a concentration ranging from 1x10 ³ to 100% by weight, preferably from 0.5% to 5% by weight relative to the total weight of the composition. 12. Use according to the preceding claim for further improving the organoleptic properties of the cosmetic composition. 13. Cosmetic care process for improving the appearance and/or comfort of the skin, of the skin appendages, in particular the hair, and/or of the mucous membranes, comprising the topical application to at least one area of skin and/or skin appendages and/or mucous membranes of porous spheres with closed porosity comprising a metal oxide and/or of a cosmetic composition comprising them. 14. Cosmetic care process according to claim 13, characterized in that the spheres are as described in any one of claims 1 to 9 and 11. 15. Cosmetic care process according to any one of claims 13 or 14, to reduce the visibility of unsightly manifestations of the skin, skin appendages and/or mucous membranes, in particular irregularities in the relief and/or texture of the skin, mucous membranes and/or skin appendages, and/or irregularities in the color of the skin and/or mucous membranes. 16. Cosmetic care process according to any one of claims 13 to 15, characterized in that at least one area of skin and/or cutaneous appendages and/or mucous membranes is chosen from the skin of the face, including the forehead, the cheeks, the nose, the temples, the so-called "T" area (forehead, nose and chin), under the eyes, the peri-orbital area, in particular dark circles, the chin, the scalp, the neck, the back, the shoulders , arms, forearms, thorax, hands, hair, beard, eyelashes, eyebrows, bust, in particular the neckline, stomach and/or armpits, legs, feet, hands, neck, thighs, hips, buttocks, waist, torso, lip contour, hair, hair and/or ocular, labial and/or oral mucosa, preferentially the skin of the face , hands, neckline. 17. Cosmetic or pharmaceutical composition, in particular dermatological, characterized in that it contains porous spheres with closed porosity as described in any one of claims 1 to 9 at a concentration ranging from lxlO ³ to 10% by weight, preferably from 0.5% to 5% by weight relative to the total weight of the composition. 18. Cosmetic composition according to the preceding claim, characterized in that it contains at least one cosmetic excipient and/or a cosmetic pigment and/or dye and/or a UV filter and/or a cosmetic active ingredient, preferably chosen from agents modifying the color of the skin and/or the radiance of the skin such as bleaching agents, anti-aging agents, in particular those acting on photo-induced aging, moisturizers, anti-pollution, in particular antioxidant, soothing, regulators and/or sebum absorbers, mattifying, prebiotic, cosmetic active acting on imperfections of the surface and/or the relief and/or the color of the skin, antibacterial, and/or agent for sensitive skin. 19. Cosmetic composition according to claim 17 or 18, characterized in that it is in the form of a serum, a lotion, a cream, a shampoo, a conditioner, an oil, a milk, an ointment, a paste, a mousse, an emulsion, a hydrogel, a shower gel, a mask, a lacquer, a spray , a wax, a powder, in particular for make-up, or a stick. 20. Cosmetic composition according to one of claims 17 to 19, characterized in that it is in the form of a slightly gelled composition and/or comprises an oily phase, preferably it is of the oily composition or oil-in-water or water-in-oil emulsion or lotion type. 21. Pharmaceutical composition, in particular dermatological, according to claim 17, for its use to improve the comfort of the skins, cutaneous appendages and/or mucous membranes presenting a pathology, in particular manifested by a loss of homogeneity and/or a deregulation and/or an irregularity of the color, of the complexion, of the secretion of sebum and/or of the relief, such as hyperpigmented, hypopigmented, hyperseborrheic, reactive, inflammatory skin, atopic, in particular skin affected by vitiligo, melanoma, couperose, telangiectasia, acne, rosacea, urticaria, psoriasis, herpes, impetigo, ecthyma, erysipelas, and/or having wounds and/or scars, in particular acne, pimples, boils, varicose veins, melasma, folliculitis, abscesses, any combination thereof.