ES2363678B1 - UV / VIS / IR RADIATION PHOTOPROTECTOR COMPOSITION WITH SILICON MICROSPHERAS AS ACTIVE COMPOUND. - Google Patents

Abstract

UV / VIS / IR radiation photoprotective composition with silicon microspheres as active compound. # Use of silicon microspheres with diameters between 0.2 and 50 µm as filter and / or electromagnetic radiation wavelength thermoregulator of between 280 nm and 180 m, more particularly of UVA, UVB absorption and IR reflection radiation. The invention also relates to compositions, which may be pharmaceutical or cosmetic, comprising said silicon microspheres and their methods of production.

Description

UV / VIS / IR radiation photoprotective composition with silicon microspheres as active compound.

The present invention relates to the use of silicon microspheres as a solar fi lter of UVA, UVB radiation by absorption and IR by reflection. The invention also relates to pharmaceutical and cosmetic compositions comprising said silicon microspheres and their methods of production.

Prior art

Nowadays it is well known that the skin is sensitive to sunlight, which can cause different alterations depending on the radiation it receives.

The electromagnetic spectrum of solar radiation is broken down into 3 types of light: ultraviolet (UV), visible (VIS) and Infrared (IR).

By convention, UV solar radiation is divided into 3 zones called:

-

UVC, corresponding to rays with wavelengths less than 290 nm, which are absorbed by the ozone of the atmospheric layer without reaching the earth's crust.

-

UVB, corresponding to wavelengths between 290 and 320 nm, causing erythema, and burns of varying degrees on the skin.

-

UVA, corresponding to wavelengths between 320 and 400 nm, which are responsible for premature skin aging processes, and to promote cancers and numerous phototoxic and photoallergic reactions.

Since the first sun creams appeared at the end of the 60s, the field of sun protection has evolved towards products capable of not only shielding UVB rays but also UVA. Typically, sunscreen agents are usually organic chromophores (chemical filters) that absorb UVB very well and to a lesser extent UVA, or particulate inorganic compounds (physical filters) which are very effective for blocking UVAs by reflection and light scattering Thus, a hybrid formulation of the sunscreen with chemical and physical fi lters may be suitable for shielding a wide area of solar spectrum radiation.

The physical fi lters are usually metal oxides and compared with the organic molecules of the fi lters cause few irritations and are physiologically inert, which are present in most sunscreen formulations. The most common are TiO2 (titanium dioxide) or ZnO (zinc oxide) particles whose size depends on the radiation they block, interacting strongly with wavelengths of approximately twice the diameter of the particle. The great drawback, from the aesthetic point of view, is the whitish effect produced by large-sized particle preparations (the most effective against visible light) on the skin due to the fact that TiO2, and to a lesser extent ZnO , have a strong diffusing effect of visible light. This problem has been solved with the increasingly widespread use of nanometric particles that make the product transparent (10-100 nm for TiO2 and 30-200 nm for ZnO) and shifts its activity to the UV zone. However, due to the size of these particles, some reports warn of their possible penetration into the body. Other studies, on the other hand, minimize this effect especially when compared to the toxicity of some organic compounds present in sunscreens (A. Nel et al. Critical reviews in toxicology, 37, 521-277, 2007;

X. Deng et al. Nanotechnology, 20, 115101, 2009).

In addition, certain studies have shown that metal oxide nanoparticles produce allergic reactions in certain individuals and their photocatalytic nature is well known to chemists, particularly those of TiO2 that could generate free radicals through UV light. To minimize this problem, several studies have focused on coating the outer layer of the particles with another material such as polymers or manganese dioxide (MnO2) (Eusolex T-PRO®, Merck Chemicals) active with free radical sequestrant. Other TiO2 particles have been coated with layers of SiO2 or Al2O3, which form hydrated oxides that can capture hydroxyl radicals, and therefore reduce surface reactions. However, some preparations of TiO2 / Al2O3 and TiO2 / Si2 have shown an increase in photocatalytic activity.

In that sense, recent research by A.O. Rybaltovskii et al, Optics and Spectroscopy, 101,590-596, 2006; and in US2007 / 0102282, they propose the use of silicon particle nanoclusters as a UV protector, underlining their respect for the environment due to their ability to hinder the formation of harmful biological compounds during the UV-induced degradation of sunscreen components .

Although research in the field of sunscreens has mainly focused on the development of UVB and UVA radiation protection products, it should be borne in mind that rays with wavelengths located in the area between 400 and 800 nm ( VIS zone) and above (IR) can also penetrate the skin and chronic exposure can cause damage and contribute to skin aging processes or lead to melanomas (HM Bassel et al. Photochemistry and Photobiology, 84, 450-462, 2008; P. Schroederet al. In Skin Aging, Eds B. Gilchrest, J. Krutmann, Springer, Berlin, 45-53, 2006).

In the range of visible radiation (VIS), apart from metal oxide particles of adequate size for the reflection of that type of light, such as ZnO and TiO2 (Hombitec®, Sachotec®, ...), they have been proposed since dyes that absorb light of different wavelengths (blue, red, yellow ...) and that used alone or in mixture give the skin a natural color, up to fl avonoids.

The biological effects of IR radiation (which is also divided by convention between IR-A (760-1400 nm), IR-B (1400-3000 nm) and IR-C (3000 nm-1 mm) are actually still little known and the results of the investigations in this regard are full of controversy IR radiation would potentiate the harmful effects of UV acting in synergy, however, other studies point to a protective effect of IR radiation against UV radiation damage. However, it should be noted that the light with wavelength in the infrared zone is thermal radiation, which causes the redness and heating of the skin that characterize the thermal erythema: they penetrate the epidermis, reach the vascular network activating the microcirculation and they produce an immediate vasodilation.For these reasons, there is great interest in investigating the effects of IR radiation on the skin and developing products capable of shielding it and acting as thermoregulators.

Some filters claim protection against infrared radiation. For example, infrared reflective particles such as so-called pearl-gloss pigments have been used in patents ES2089356 and US6187298. These are particles with layers or flakes structure generally made of mica as a support material coated with TiO2 or SnO2 of different thicknesses and which can be doped with iron or cerium.

TiO2 in its rutile-like structure has a high protective power against IR radiation given its reflective property for those wavelengths (this property is absent when its crystalline structure is anatase). This gives the sunscreens that contain it greater anti-erythema properties (L. Violin, et al, International Journal of Cosmetic Science, 16, 113-120, 1994). However, there are still few developments of fi lters of IR radiation.

From all of the above, the absence of a single compound capable of covering a wide range of protection from UV radiation to thermal radiation (IR) and which is totally harmless stands out.

Description of the invention

The present invention provides a new use of silicon microspheres (whose description and synthesis procedure is detailed in patent application ES2331824 and in the publication: Fenollosa R., et al., Adv. Mater., 20, 95-98 , 2008), as protective compositions of sunlight, effective against broad-spectrum radiation (UVA + UVB), as well as IR radiation. These compositions have as an active component or principle silicon microspheres of a size between 0.2 m and 50 μm, capable of absorbing UV radiation and reflecting the thermal IR radiation conferring a thermoregulatory effect.

In this way, the invention provides the use of silicon microspheres as a solar fi lter of UVA, UVB absorption and IR reflection radiation, while providing pharmaceutical and cosmetic compositions comprising said silicon microspheres and their methods of obtaining. These compositions can act as sunscreens in a wide range of electromagnetic radiation and as thermoregulators. That is, they offer protection against the harmful effects of the sun, both in the UV zone and in the area of longer wavelengths (VIS and IR) of the solar spectrum and, in turn, allow, by reflection of the infrared radiation, to maintain a constant temperature on the skin or other surfaces where the preparations of the present invention are applied.

Therefore, a first aspect of the present invention refers to the use of silicon microspheres with a diameter between 0.2 and 50 μm as a solar fi lter and / or as a thermoregulator, with the capacity to filter electromagnetic radiation of wavelength between 280 nm and 180 μm. Preferably these radiations belong to the wavelength range of UVA, UVB, VIS and IR, and more preferably UVA, UVB and IR.

By "solar fi lter" in the present invention is meant a substance that re fl ects or absorbs solar radiation preventing it from penetrating the surface to be protected and / or acting by re fl ecting or absorbing solar radiation and transforming it into another type of energy that is not harmful for said surface.

The term "thermoregulator" means substances that keep the temperature constant on a surface where it is applied, by means of the reflection of the infrared radiation.

The silicon microspheres used in the present invention are spherical microparticles with a very regular and smooth surface. These microspheres may have undergone surface modification treatments, for example an increase in hydrophilic character.

A preferred embodiment of the present invention comprises silicon microspheres for use as a pharmaceutical composition. More preferably, silicon microspheres are used as a pharmaceutical composition for the prevention of sunburn or damage. Even more preferably when sunburn or damage occurs on skin and / or hair.

By "sun damage" refers to pathologies caused by exposure to the sun, for example they can be selected from actinic keratosis or skin cancer. Different types of skin cancer can occur, for example basal cell carcinoma (also called basal cell epithelioma), squamous cell carcinoma (also called spinocellular epithelioma) or melanoma.

In a preferred embodiment, this pharmaceutical composition is in the form suitable for topical administration.

Such compositions and / or their formulations can be administered to an animal, including a mammal and, therefore, to man, by solutions, hydroalcoholic solutions, emulsions, lotions, ointments, gels, creams that can be lipophilic or hydrophilic, pastes or any other. suitable form known to any expert in the field. Preferably it is a lotion or a cream, which can be lipophilic or hydrophilic.

"Lotion" in the present invention is understood as a preparation made with an aqueous or low-alcohol vehicle containing dissolved or suspended substances.

By "cream" is meant in the present invention a multiphase preparation consisting of a lipophilic phase and an aqueous phase. Creams are classified in turn into:

-

Lipophilic creams: the continuous phase is lipophilic, these emulsions are known by W / O (water in oil)

-

Hydrophilic creams: the continuous phase is aqueous, these emulsions are known O / W (oil in water)

The dosage to obtain a therapeutically effective amount depends on a variety of factors, such as age, skin type, tolerance, etc. In the sense used in this description, the term "therapeutically effective amount" refers to the amount of the composition of the invention that produces the desired effect and, in general, will be determined, inter alia, by the characteristics of said composition. and the therapeutic effect to be achieved. It is contemplated that the compositions of the present invention may be pharmaceutical compositions, which comprise a therapeutically effective amount of the silicon microspheres, together with, a therapeutically effective amount of a pharmaceutical carrier.

By "pharmaceutical composition" is meant in the present invention a compound that contains at least one high purity chemical substance used in the prevention of a disease, or to prevent the occurrence of an undesired physiological process.

In another preferred embodiment, the silicon microspheres are used for the preparation of a cosmetic composition. In a more preferred embodiment the cosmetic composition is used for the prevention of spots and premature aging of the skin / or hair and other adverse effects, on the skin and / or hair, of solar radiation. Like the pharmaceutical composition, the cosmetic composition is in the form suitable for topical administration.

By "cosmetic composition" is meant in the present invention a product used for body hygiene

or with the purpose of improving beauty, especially of the face, body, lips, etc.

Another preferred use of silicon microspheres is for the manufacture of a protective composition of all types of materials. These materials being protected selected from natural, synthetic or any combination thereof. The materials may be wood, plastics, metals or alloys, etc., their combinations, or any other type of material known to any person skilled in the art. These compositions act as a protective barrier against aging and deterioration of these materials, due to the electromagnetic radiation that could be affecting them.

In the uses mentioned above, the use of these microspheres is as an active component, since it acts as a solar fi lter and other electromagnetic radiation, absorbing, above all, UVA, UVB radiation and reflecting IR radiation.

In the present invention, since the microspheres are a physical fi lter, they have the advantage of not causing irritation and of being physiologically inert. And being small particles of micrometer size they will also have the additional advantage of preventing the composition from looking whitish when applied. In turn, being micrometric they do not cause allergies such as the nanometric particles of TiO2 or ZnO.

A second aspect of the present invention relates to a pharmaceutical composition comprising silicon microspheres with diameters between 0.2 and 50 µm, in addition to a pharmaceutically effective vehicle.

In a more preferred embodiment the silicon microspheres have diameters between 0.2 and 5 μm.

The percentage by weight of the silicon microspheres is preferably between 0.5 and 5%, more preferably between 0.8 and 2% with respect to the weight of the final composition.

The dosage to obtain a therapeutically effective amount depends on a variety of factors, such as age, skin type, tolerance, etc. In the sense used in this description, the term "therapeutically effective amount" refers to the amount of the composition of the invention that produces the desired effect and, in general, will be determined, inter alia, by the characteristics of said composition. and the therapeutic effect to be achieved. It is contemplated that the compositions of the present invention may be pharmaceutical compositions, which comprise a therapeutically effective amount of the silicon microspheres, together with, a therapeutically effective amount of a pharmaceutical carrier.

The pharmaceutical composition in a preferred embodiment is characterized by further comprising at least one other component selected from thickener, emulsifier, moisturizer, colorant or any combination thereof.

This pharmaceutical composition in a preferred embodiment is in a form suitable for topical administration, as described above. Being in another more preferred embodiment characterized by being a lotion, or a lipophilic or hydrophilic cream.

A third aspect of the present invention refers to a cosmetic composition comprising silicon microspheres with diameters between 0.2 and 50 μm.

In a preferred embodiment the silicon microspheres have diameters between 0.5 and 5 μm.

The percentage by weight of the silicon microspheres is preferably between 0.5 and 5%. And more preferably between 0.8 and 2% with respect to the final cosmetic composition.

The cosmetic composition of the present invention may further comprise at least one additive that is selected from thickeners, emulsifiers, moisturizers, colorants or any combination thereof.

The cosmetic composition is preferably in a form suitable for topical administration, as defined above. More preferably said form suitable for topical administration is a lotion,

or a lipophilic or hydrophilic cream.

These pharmaceutical and cosmetic compositions may contain only silicon microspheres as active component against solar radiation or also contain other protective ingredients such as chemical UV filters and / or known physical filters. Chemical filters are understood as chromophore compounds that absorb light of a certain wavelength, and physical filters, inorganic compounds that reflect and disperse light. These cosmetic compositions, like pharmaceuticals, can also be used as thermoregulatory creams.

The silicon microspheres used for the preparation of the different pharmaceutical or cosmetic compositions can be subjected to surface modification treatments, such as an increase in the hydrophilic character.

Thus, a fourth aspect of the present invention relates to a process for the manufacture of a pharmaceutical or cosmetic composition as described above, where silicon microspheres are pretreated by grinding.

In a preferred embodiment of the process of the present invention, silicon microspheres are added over an aqueous solution. In this case it would be possible to make a lotion, or a hydrophilic cream, to which an oil will be added later.

In a preferred embodiment the silicon microspheres are added to the aqueous phase at a concentration between 0.5 and 5% by weight.

Also the silicon microspheres can preferably be added on an aqueous solution to subsequently form an emulsion with oil, thereby achieving a lipophilic cream.

Throughout the description and the claims the word "comprises" and its variants are not intended to exclude other technical characteristics, additives, components or steps. For those skilled in the art, other objects, advantages and characteristics of the invention will be derived partly from the description and partly from the practice of the invention. The following examples and drawings are provided by way of illustration, and are not intended to be limiting of the present invention.

Description of the fi gures

Figure 1: Diameter distribution of silicon colloids used in the development of sunscreen creams. The distribution is centered around 1.8 microns and has a width (σ) of 0.5 microns.

Figure 2: Effective Mie scattering section averaged according to the distribution of colloid diameters in Figure 1.

Figure 3: Optical transmission spectra obtained, in the IR range, of the samples prepared in the form of an O / W emulsion, with silicon microspheres (0.8% by weight and with the size distribution of Figure 1) object of the present invention (solid line), and of the samples prepared according to the same procedure with 0.8% by weight of TiO2 particles (P-25 Degussa) (broken line), with different amounts on the glass substrates (11 mg / cm2) and PMMA-HD6® (2 mg / cm2).

Figure 4: Optical transmission spectra obtained, in the UV range, of the samples prepared in the form of O / W emulsions, with silicon microspheres (0.8% by weight and with the size distribution of Figure 1) object of the present invention, and with the samples prepared according to the same procedure with TiO2 particles (P25 Degussa), with the substrates PMMA-HD6® (solid line) and PMMA-HD2® (dashed line). With quantities on substrates of 2 mg / cm2.

Figure 5: Distribution of diameters (Φ) of silicon colloids used to calculate the average effective section of Figure 6. The distribution is centered around 2.5 microns and has a width (σ) of 0.75 microns.

Figure 6: Emitting power of the human body (curve below) as a function of the wavelength calculated from Planck's law, considering that it is a black body that is at a temperature of 37 ° C. The above curve corresponds to a calculation of the effective Mie scattering section averaged according to the distribution of colloid diameters in Figure 5. In both curves the maximum is centered around 9.3 microns.

Examples

The invention will now be illustrated by tests carried out by the inventors, which demonstrates the specificity and effectiveness of silicon microspheres as a solar fi lter, and the corresponding optical measurements. By way of comparison, the results obtained with the same type of preparation are also presented but replacing the silicon microparticles with TiO2 (P25 Degussa).

Through the following examples, the optical properties of various sunscreen preparations object of the present invention are presented. Optical transmittance measurements have been performed both in the Infrared, by Fourier transform Infrared Spectroscopy (FTIR), and in the ultraviolet range. (UV)

The optical measurements presented in this document have been made on thin layers of the different sunscreen preparations, of identical thickness on glass substrates and PMMA substrates (Helioplate® HD6 (roughness of 6 microns), Helioplate HD2 (roughness 2 microns) -Helioscreen), which simulate the skin. The amounts of preparation applied on the substrates vary between 2 mg / cm2 (on PMMA) and 11 mg / cm2 (on glass).

The silicon microspheres, with size distribution according to the curve of Figure 1, were synthesized according to the procedure detailed in patent application ES2331824 and in the publication: "Fenollosa R., et al., Adv. Mater., 20, 95-98,2008 ”, and were subjected to a grinding in order to obtain as loose microparticles as possible and without the presence of aggregates. These microspheres give rise to an average near-infrared Mie scattering section illustrated in Figure 2. This scattering is responsible for shielding solar infrared radiation.

Example 1

This example describes the preparation of an oil-in-water (O / W) emulsion with silicon microparticles as an active compound and its optical properties in the Infrared range between 850 nm and 2.2 microns and the UV of 280nm at 450 nm. The results of the optical transmissions of the preparations on glass plates and on rough and 6 micron PMMA plates are shown.

Preparation of an oil-in-water emulsion (O / W)

0.3% by weight of methylcellulose is dissolved in water at 70 ° C, with stirring. Once a homogeneous solution is obtained, 4% self-emulsifiable glyceride monostearate is added while stirring.

Prior to use, silicon microparticles synthesized according to the method described in patent application ES2331824 and in the publication: "Fenollosa R., et al., Adv. Mater., 20, 95-98,2008 ”, with size distribution according to the curve of Figure 1, were subjected to grinding to obtain individual microspheres and avoid aggregates of various particles.

The silicon microparticles are added to the aqueous solution (between 0.8 and 1% by weight with respect to the total weight of the emulsion) under strong mechanical agitation (3000 rpm).

After 10-15 minutes, mineral oil is added gradually (between 20-30% by weight with respect to the total weight) while stirring vigorously for another 10-15 minutes.

The preparation obtained has a creamy and smooth touch due to the regular geometry of the silicon microspheres.

Sample preparation for optical measurements

11 mg / cm2 and 2 mg / cm2 of preparation are spread evenly on a glass object holder and PMMA plates (Helioplate®. HD) respectively, sold by Helioscreen. PMMA plates are internationally accepted as a measuring substrate for solar preparations. PMMA plates of 6 μm roughness (HD6) and 2 μm roughness (HD2) were used.

Optical measurements

Measurements in the Infrared range

Samples prepared in the form of an emulsion (O / W), containing silicon microspheres of the present invention, were analyzed optically by infrared spectroscopy in the range between 0.85 μm and 2.2 μm considering the substrates (glass or PMMA -HD) as a reference, and varying the amounts of emulsion distributed by area (11 mg / cm2 and 2 mg / cm2 respectively).

With the sample containing 0.8% by weight of silicon microspheres and prepared with emulsion amounts of 11 mg / cm2 (on glass), optical transmission values between 5% (1 μm) and 10% (2.2 μm) are obtained ).

With the sample containing 0.8% by weight of silicon microspheres and prepared with emulsion amounts of 2 mg / cm2 (on HD6), optical transmission values between 48% (1 μm) and 65% (2.2 μm) are obtained ).

Measures in the UV range

Samples prepared in the form of emulsion (O / W), containing silicon microspheres and object of the present invention, were analyzed optically by UV spectroscopy, with integrating sphere, in the range between 280 nm and 450 nm considering air as reference , and on 2 PMMA-HD substrates of different roughness (6 μm (HD6) and 2 μm (HD2)). Emulsion amounts of 2 mg / cm2 were used.

With the sample containing 1% by weight of silicon microspheres and prepared on a 6 μm roughness PMMA-HD® (HD6) substrate, optical transmission values between 41% (280 nm) and 65% (450 nm) are obtained. The sample containing 1% by weight of silicon microspheres and prepared on a substrate of PMMA-HD® (HD2) of roughness 2 μm gives optical transmission values between 40% (280 nm) and 64% (450 nm).

For comparison, a sample was prepared according to the same preparation and characterization procedure as detailed in example 1, but replacing the silicon microspheres with Titania microparticles (P25-Degussa), that is to say with the same weight percentage as the of silicon microspheres. Figures 3 and 4 show the experimental results of optical transmission obtained.

Figure 3 compares the results of optical transmission in the IR range with emulsions of the present invention prepared with silicon microparticles (example 1) and with emulsions prepared with TiO2 particles (P25 Degussa) with the same weight percentage as that of the silicon microspheres, on glass substrates and PMMA-HD6®, varying the amounts of emulsion distributed by area (11 mg / cm2 and 2 mg / cm2 respectively). It is observed how emulsions with silicon microspheres produce a greater attenuation of infrared radiation than emulsions with microparticles of Titania.

Figure 4 compares the results of optical transmission in the UV range, with integrating sphere, obtained with 2 mg / cm2 of the preparations containing the silicon microparticles of the present invention and of the preparations containing the TiO2 particles (P25 Degussa ) with the same weight percentage as silicon microparticles, on PMMA-HD6® substrates (6 μm roughness) (continuous line) and PMMA-HD2 (2 μm roughness) (dashed line). Similar transmission values are observed for both types of emulsion, that of titania and that of silicon, however in the range of wavelengths from 350 nm to 440 nm the emulsion with silicon microparticles produces 10% more screening than the emulsion with titania microparticles.

Example 2

This example describes the preparation of an aqueous base cream with silicon microparticles as an active compound, and its optical properties in the Infrared range between 850 nm and 2.2 microns and UV 280 nm at 450 nm. The results of the optical transmissions with different quantities (11 mg / cm2 and 2 mg / cm2) are distributed on glass and PMMA-HD® plates respectively.

Preparation of a cream

0.3% by weight of methylcellulose is dissolved in water at 70 ° C, with stirring (2000 rpm). Once a homogeneous solution is obtained, 4% of self-emulsifiable glyceride monostearate is added while stirring.

Prior to use, silicon microparticles synthesized according to the method described in patent application ES2331824 and in the publication: "Fenollosa R., et al., Adv. Mater., 20, 95-98,2008 ”, with size distribution according to the curve of Figure 1, were subjected to grinding to obtain individual microspheres and avoid aggregates of various particles.

The silicon microparticles are added to the aqueous solution (between 0.8 and 1% by weight with respect to the total weight) under strong mechanical agitation (3000 rpm).

Sample preparation for optical measurements

11 mg / cm2 and 2 mg / cm2 of preparation are spread evenly on a glass object holder and PMMA plates (Helioplate®.HD marketed by Helioscreen).

Optical measurements

Infrared range measurements

Samples prepared in the form of an aqueous cream, containing silicon microspheres and object of the present invention, were analyzed optically by infrared spectroscopy in the range between 0.85 μm and 2.2 μm considering the substrates (glass or PMMA-HD ) as a reference, and varying the amounts of cream spread by area (11 mg / cm2 and 2 mg / cm2 respectively).

With the sample containing 0.8% by weight of silicon microspheres and with cream amounts of 11 mg / cm2 (on glass), optical transmission values between 33% (1 μm) and 27% (2.2 μm) are obtained .

With the sample containing 0.8% by weight of silicon microspheres and with cream amounts of 2 mg / cm2 (over PMMA-HD® (HD6) roughness 6 μm), optical transmission values between 79% (1 μm) are obtained ) and 84% (2.2 μm)

Measures in the UV range

The prepared samples object of the present invention were optically analyzed by UV spectroscopy, with integrating sphere, in the range between 280 nm and 450 nm considering air as reference. Preparation amounts of 2 mg / cm2 were used.

With the sample containing 1% by weight of silicon microspheres and prepared on a 6 μm roughness PMMA-HD6® (HD6) substrate, optical transmission values between 41% (280 nm) and 67% (450 nm) are obtained.

With the sample containing 1% by weight of silicon microspheres and prepared on a substrate of PMMA-HD® (HD2) of roughness 2 μm, optical transmission values between 46% (280 nm) and 79% (450 nm) are obtained.

For comparison, a sample was prepared according to the same preparation and characterization procedure as detailed in example 2 (aqueous base cream), but replacing the silicon microspheres with Titania microparticles (P25-Degussa), that is, with the same weight percentage as that of silicon microspheres.

Measurements in the Infrared range

Table 1 summarizes and compares the results of optical transmission in the IR range obtained with the creams prepared with silicon microparticles of the present invention and TiO2 particles (P25 Degussa), on glass substrates and PMMA-HD6® varying the amounts of emulsion distributed by area (11 mg / cm2 and 2 mg / cm2 respectively).

TABLE 1

Optical transmission results in the IR range

Measures in the UV range

Table 2 summarizes and compares the results of optical transmission in the UV range, with integrating sphere, obtained with 2 mg / cm2 of the preparations containing the silicon microparticles of the present invention and 2 mg / cm2 of the preparations containing the TiO2 particles (P25 Degussa) on PMMA-HD6® substrates (6 μm roughness) and PMMA-HD2 (2 μm roughness).

TABLE 2

Optical transmission result in the IR range

Example 3

This example describes the preparation of an oil with silicon microparticles as an active compound and the optical properties of this same preparation in the Infrared range between 850 nm and 2.2 microns and UV 280nm at 450 nm. The results of the optical transmissions of the preparations with different quantities per area on glass plates and 6 micron roughness PMMA are shown.

Oil preparation

Prior to use, silicon microparticles synthesized according to the method described in patent application ES2331824 and in the publication: "Fenollosa R., et al., Adv. Mater., 20, 95-98,2008 ”, with size distribution according to the curve of Figure 1, were subjected to grinding to obtain individual microspheres and avoid aggregates of various particles.

The silicon microparticles are added to a mineral oil (between 0.8% and 1% by weight with respect to the total weight) under strong mechanical agitation (3000 rpm).

Sample preparation for optical measurements

11 mg / cm2 and 2 mg / cm2 of preparation are spread evenly on a glass object holder and PMMA plates respectively (Helioplate®. HD6).

Optical measurements

Measurements in the Infrared range

The oil samples prepared with silicon microspheres and object of the present invention were analyzed optically by infrared spectroscopy in the range between 0.85 μm and 2.2 μm considering the substrate (glass or PMMA-HD) as a reference.

With the oil sample containing 0.8% by weight of silicon microspheres and prepared with 11 mg / cm2 on glass, optical transmission values of 78-79% are obtained.

With the oil sample containing 0.8% by weight of silicon microspheres and prepared with 2 mg / cm2 on HD6, optical transmission values of 47-50% are obtained.

Measures in the UV range

The oil samples prepared with silicon microspheres and object of the present invention were optically analyzed by UV spectroscopy, with integrating sphere, in the range between 280 nm and 450 nm considering air as reference. Two types of substrates with roughness of 6 (HD6) and 2 microns (HD2), and preparation amounts of 2 mg / cm2 were used.

With the oil sample containing 1% by weight of silicon microspheres and prepared on a 6 μm roughness PMMA-HD® (HD6) substrate, optical transmission values between 43% (280 nm) and 76% (450 nm) are obtained )

With the oil sample containing 1% by weight of silicon microspheres and prepared on a 2 μm roughness PMMA-HD® (HD2) substrate, optical transmission values are obtained between 48% (280 nm) and 76% (450 nm ).

Example 4

Example of a cream to maintain body heat

Examples of the sunscreen creams made above are based on a distribution of colloid diameters centered around 1.8 microns and with a size dispersion of 30% (see Figure 1). This size distribution shields infrared light from solar radiation with near-infrared wavelengths. If a different size distribution is chosen, for example a distribution such as that of Figure 5, with an average size of about 2.5 microns and with 30% dispersion, a cream developed from these colloids would resemble infrared radiation with a wavelength of 9.5 microns, which is precisely the radiation emitted by the human body. Therefore this cream can be used to maintain body heat. Figure 6 illustrates these reasoning: the curve below shows the radiation of the human body (at 37 ° C) calculated from Planck's law assuming it is a black body and the curve above shows the effective section of average Mie scattering at which gives rise to the size distribution of Figure 5. It is observed that the radiation and scattering maxima respectively coincide and are located around 9.5 microns.

Claims (30)

one.

Use of silicon microspheres with diameters between 0.2 and 50 μm as a fi lter and / or electromagnetic radiation thermoregulator with a wavelength between 280 nm and 180 μm.

2. Use according to claim 1, wherein the radiations are UVA, UVB and IR.

3.

Use of the microspheres according to any of claims 1 or 2, for the preparation of a pharmaceutical composition.

Four.

Use according to claim 3, for the prevention of sunburn or damage.

5.

Use according to claim 4, wherein sunburn or damage occurs on skin and / or hair.

6. Use according to any of claims 3 or 4, wherein the pharmaceutical composition is in the form suitable for topical administration. 7. Use according to claims 4 to 6 wherein the sun damage can be selected from actinic keratosis or skin cancer.

8.

Use of the microspheres according to any of claims 1 or 2, for the preparation of a cosmetic composition.

9. Use according to claim 8, for the prevention of spots and premature aging of the skin / or hair.

10.

Use according to any of claims 8 or 9, wherein the cosmetic composition is in the form suitable for topical administration.

eleven.

Use according to any of claims 1 or 2, for the manufacture of a protective composition of materials.

12.

Use according to claim 11, wherein the materials to be protected are selected from natural, synthetic or any combination thereof.

13.

Pharmaceutical composition comprising silicon microspheres with diameters between 0.2 and 50 μm and a pharmaceutically acceptable carrier.

14.

Pharmaceutical composition according to claim 13, wherein the silicon microspheres have diameters between 0.2 and 5 μm.

fifteen.

Pharmaceutical composition according to any of claims 13 or 14, wherein the weight percentage of the silicon microspheres is between 0.5 and 5% with respect to the final composition.

16.

Pharmaceutical composition according to any of claims 13 to 15, wherein the percentage by weight of the silicon microspheres is between 0.8 and 2% with respect to the final composition.

17.

Pharmaceutical composition according to any of claims 13 to 16, further comprising at least one component that is selected from the list comprising thickener, emulsifier, moisturizer, colorant or any combination thereof.

18.

Pharmaceutical composition according to any of claims 13 to 17, in a form suitable for topical administration.

19.

Pharmaceutical composition according to any of claims 13 to 18, characterized in that it is a lotion, a lipophilic or hydrophilic cream.

20. Cosmetic composition comprising silicon microspheres with diameters between 0.2 and 50 μm.

twenty-one.

Cosmetic composition according to claim 20, wherein the silicon microspheres have diameters between 0.5 and 5 μm.

22

Cosmetic composition according to any of claims 20 or 21, wherein the percentage by weight of the silicon microspheres is between 0.5 and 5%.

2. 3.

Cosmetic composition according to any of claims 20 to 22, wherein the percentage by weight of the silicon microspheres is between 0.8 and 2%.

24.

Cosmetic composition according to any of claims 20 to 23, further comprising at least one additive that is selected from thickeners, emulsifiers, moisturizers, colorants or any combination thereof.

25.

Cosmetic composition according to any of claims 20 to 24, in a form suitable for topical administration.

26.

Cosmetic composition according to claim 25, wherein the suitable form for topical administration is a lotion, a lipophilic or hydrophilic cream.

27.

Process for the manufacture of a pharmaceutical composition according to any of claims 13 to 19 or a cosmetic composition according to any of claims 20 to 26, wherein the silicon microspheres are pretreated by grinding.

28.

Process according to claim 27, wherein the silicon microspheres are added over an aqueous solution.

29.

Process according to any of claims 27 or 28, wherein the silicon microspheres are added on an aqueous solution to subsequently form an oil emulsion.

SPANISH OFFICE OF THE PATENTS AND BRAND Application no .: 201030129 SPAIN Date of submission of the application: 01.02.2010 Priority Date: REPORT ON THE STATE OF THE TECHNIQUE 51 Int. Cl.: A61K8 / 25 (2006.01) A61K8 / 00 (2006.01) RELEVANT DOCUMENTS

Category

Documents cited Claims Affected

TO

WO 0124762 A2 (L’OREAL) 12.04.2001, the whole document. one

TO

GB 2416524 A (DOW CORNING CORPORATION) 01.02.2006, the whole document one

TO

US 6187298 B1 (KURZ et al.) 13.02.2001, the entire document. one

Category of the documents cited X: of particular relevance Y: of particular relevance combined with other / s of the same category A: reflects the state of the art O: refers to unwritten disclosure P: published between the priority date and the date of priority submission of the application E: previous document, but published after the date of submission of the application

This report has been prepared • for all claims • for claims no:

Date of realization of the report 08.07.2011

Examiner A. Amaro Roldan Page 1/4

REPORT OF THE STATE OF THE TECHNIQUE Application number: 201030129 Minimum documentation searched (classification system followed by classification symbols) A61K Electronic databases consulted during the search (name of the database and, if possible, terms of search used) INVENES, EPODOC, WPI State of the Art Report Page 2/4  WRITTEN OPINION Application number: 201030129 Date of Written Opinion: 08.07.2011 Statement

Novelty (Art. 6.1 LP 11/1986)

Claims Claims 1-29 IF NOT

Inventive activity (Art. 8.1 LP11 / 1986)

Claims Claims 1-29 IF NOT

The application is considered to comply with the industrial application requirement. This requirement was evaluated during the formal and technical examination phase of the application (Article 31.2 Law 11/1986).  Opinion Base.- This opinion has been made on the basis of the patent application as published. State of the Art Report Page 3/4  WRITTEN OPINION Application number: 201030129 1. Documents considered.- The documents belonging to the state of the art taken into consideration for the realization of this opinion are listed below.

Document

Publication or Identification Number publication date

D01

WO 0124762 A2 (L’OREAL) 12.04.2001

D02

GB 2416524 A (DOW CORNING CORPORATION) 01.02.2006

D03

US 6187298 B1 (KURZ et al.) 13.02.2001

2. Statement motivated according to articles 29.6 and 29.7 of the Regulations for the execution of Law 11/1986, of March 20, on Patents on novelty and inventive activity; quotes and explanations in support of this statement The present invention relates to silicon microspheres with diameters between 0.2 and 50 µm as a filter and / or thermoregulator of electromagnetic wavelength radiation between 280 nm and 180 µm, specifically UVA and UVB radiation by absorption and IR by reflection. The invention also relates to pharmaceutical or cosmetic compositions for the prevention of sunburn or sun damage that occur on the skin and / or hair comprising said silicon microspheres in amounts between 0.5% and 5% by weight, as well as the procedure for obtaining (claims 1-29). D01 refers to a process to improve the stability of the UV rays of a sunscreen filter, which consists in incorporating said filter in a substance produced by a sol-gel process from at least one silicon alkoxide and at least a surfactant It also refers to a cosmetic and / or dermatological composition against ultraviolet rays comprising said active ingredient (summary). D02 refers to microcapsules with siloxane walls formed in situ. The cosmetic or pharmaceutical composition has the active material inside and the sunscreen formed by polysiloxanes preferably tetraalkoxy- or trialkoxysilanes that surrounds it (summary). D03 refers to protective filters for the VIS and IR region for the preparation of sunscreens and their use in cosmetics (summary).  NEW AND INVENTIVE ACTIVITY None of the cited documents, considered alone or in combination, reveal the invention defined in claims 1-29 of the present application. Furthermore, there are no suggestions in the cited documents that direct the person skilled in the art towards said invention. Therefore, the object of claims 1-29 meet the requirements of novelty and inventive activity in accordance with Arts. 6 and 8 of Patent Law 11/86. State of the Art Report Page 4/4