Agar beads and cosmetic composition comprising same

Abstract

Agar beads comprising a material extending from the center of the beads to the surface of the beads, said material comprising agar-agar and cellulose gum.

Description

Description Title of the invention: Agar beads and composition COSMETICS INCLUDING THEM

[0001] technical field

[0002] The present invention relates to agar beads usable for the manufacture of a cosmetic composition in an all-aqueous formulation, i.e. without an oily phase.

[0003] The present invention finds applications particularly in the field of cosmetics, and finds a more particular application as a formulation for face or body care, hair care, makeup, and may possibly find applications for rinse-off products, such as shower gels and / or shampoos.

[0004] State of the art

[0005] In the field of cosmetics, the use of compositions incorporating spherical particles is well-established. Such particles consist of a core containing alginate and are enclosed in a shell, thus forming spherical elements that can be described as capsules. These alginate capsules have a solid outer shell and a liquid core. Such capsules or spheres should be distinguished from a bead-like element, a bead being a homogeneous element from its center to its periphery. Furthermore, the preparation methods used for these alginate capsules make it difficult to integrate an ingredient into the core of the capsule, and the presence of a shell introduces undesirable elements (waste) onto the skin when applied to the body. In addition, rupturing the capsules to control the release of their contents is difficult to manage.

[0006] Other particles in the form of transparent capsules are also known to have been used in prior art cosmetic compositions. These transparent capsules are prepared by carrying out a coacervation reaction between a carbomer (acrylate polymer) and amodimethicone, or by a reaction between such a carbomer and the gelling agent. of an oily phase. The use of materials from synthetic chemistry, such as acrylates and their polymers, is incompatible with the naturalness sought in the context of the present invention, and in particular with good conformity with reference to the ISO 16128 standard in the field of cosmetics.

[0007] To avoid these drawbacks, agar beads are used in hydrogel bead compositions, for example, as described in patent application EP 3 697 503. This document discloses agar beads with a non-homogeneous structure consisting of a material containing inclusions, this structure being described as "entrapment"; these beads contain fragrance and are suspended in a cosmetic gel. However, such beads incorporating agar material are poorly suited for use in cosmetic compositions because the visual appearance is not desirable, and also because controlling the rupture of the beads is difficult during use by the end consumer; this rupture must be deliberately induced to release one or more ingredients contained within the beads, such as a fragrance.

[0008] Another example of agar beads for cosmetic use is described in application EP 1 227 796. The described beads may contain quaternary cellulose, particularly those marketed under the references CRODACEL™ QM (PG-hydroxyethylcellulose cocodimonium chloride (and) Aqua) or CRODACEL™ QS (PG-hydroxyethylcellulose steardimonium chloride (and) Aqua). However, such agar beads have the disadvantage of not breaking easily enough to release their contents, and / or lack the desired shape and visual appearance, especially when incorporated into a cosmetic gel. Prior art agar beads may also have the disadvantage of excessive release of their ingredients into the cosmetic gel in which they are incorporated.

[0009] There is a strong consumer demand for face, body, and hair care products in transparent containers (typically bottles) that allow consumers to see the ingredients before use. To meet this demand, it is necessary to provide... Compositions with an improved visual appearance, particularly through the incorporation of homogeneous particles exhibiting well-controlled transparency, gloss, and / or color. Technical solutions are also sought that, in addition to the aforementioned visual advantages, allow for a transformation of the composition upon expulsion from the aforementioned container, while preserving the qualities of the cosmetic composition in terms of application to the body (skin, hair, etc.) with the best possible dispersion of the ingredients contained within the composition. Finally, the aim of the present invention is to obtain spherical beads that are resistant to packaging and transport, stabilized, and easily crushed under the consumer's finger.

[0010] There is therefore a real need to develop usable particles dispersed in a cosmetic medium while overcoming the defects, disadvantages and obstacles of the aforementioned prior art. Description of the invention

[0011] The inventors have succeeded in developing, quite unexpectedly, a composition in the form of agar beads, exhibiting improved properties for the cosmetic use of said beads.

[0012] In particular, the inventors were able to demonstrate that the desired property of the beads could be obtained by combining agar (or "agar-agar") with CAS number 9002-18-0, with cellulose gum (translated into English as "cellulose gum"), with CAS number 9004-32-4.

[0013] To this end, the present invention relates to agar beads comprising a material extending from the center of the beads to the surface of the beads, said material comprising agar-agar and cellulose gum. The beads according to the invention are solid beads, that is to say, entirely filled with the material.

[0014] Advantageously, the agar-agar is a commercially available product from IWASE COSFA Europe® under the reference ina kanten CS-83TR, CS-301TR, CS-310TR, or CS-320TR. Preferably, the agar-agar has a tensile strength of 10 to 400 g / cm³. 2 advantageously from 90 to 320 g / cm² 2 and preferably 150 to 250 g / cm 2 (1.5%). Preferably, the resistance force is determined using a rheometer equipped with a 1 cm cylindrical piston. 2Preferably, the agar-agar has a pH of 5 to 8, and preferably 6 to 7. Preferably, the pH is determined using a pH meter and in accordance with ISO 4316. Preferably, the agar-agar has a viscosity of 2 to 5 mPa·s, and preferably 3 to 4 mPa·s at 80°C. Preferably, the viscosity is determined according to the method described in ISO 2555.

[0015] Advantageously, the cellulose gum is a cellulose gum marketed by the company Ashland industrie France SAS™ under the reference Blanose® CMC 7H 3 SF or CM 2000S.

[0016] Preferably, the mass percentage of agar-agar in the beads is 0.25 to 2.25%, preferably 0.50 to 2.00%; the percentages being given in mass relative to the total mass of the bead.

[0017] Preferably, the mass percentage of cellulose gum in the beads is from 0.05 to 5.50%, preferably from 0.5 to 5%; the percentages being given in mass relative to the total mass of the bead.

[0018] Advantageously, the average diameter of the beads is less than or equal to 5000 µm and preferably between 1500 µm and 2000 µm. The average diameters of the beads are measured by evaluating their size under a binocular microscope.

[0019] Advantageously, the beads according to the invention comprise at least one element selected from a preservative, preferably a polyol, a solubilizer, a fat, a mother-of-pearl, a pigment, a colorant such as titanium dioxide, or a vegetable oil. Advantageously, the preservative is an organic acid, preferably a carboxylic acid having from 1 to 12 carbon atoms, which is advantageously sorbic acid.

[0020] Advantageously, the preservative is a carboxylic acid taken in a content of 0.005 to 0.2%.

[0021] Advantageously, the polyol is glycerol and preferably the polyol is taken in a content of 1 to 5%.

[0022] Advantageously, the beads according to the invention include a fragrance.

[0023] The present invention also relates to a method for preparing agar beads as described previously in the scope of the invention, comprising the following steps: a- prepare an aqueous mixture of agar-agar and cellulose gum, optionally comprising at least one polyol; b- bring the mixture obtained in step a- to a temperature of 85 to 90 °C; c- allow the mixture obtained in step b- to cool to a temperature of 40 to 70 °C, then pour, preferably by prilling, said mixture drop by drop into an oily phase maintained at a temperature below 35 °C and preferably from 4 to 25 °C; d- sieve the suspension obtained in step c- and optionally rinse the beads obtained with water, possibly purified.

[0024] Advantageously, agar-agar is as defined previously within the scope of the present invention.

[0025] Advantageously, the oil phase of step c- comprises an oil selected from vegetable oils, said vegetable oil preferably being selected from castor oil, a cocoglyceride, palmitic oil, isopropyl myristate and caprylic / capric triglyceride.

[0026] The oil is preferably selected as having a viscosity of less than 2000 to 4000 mPa·s (cP, centipoise). Such a viscosity allows for an interfacial tension with water of less than 10 mN / m. The inventors unexpectedly observed, during the implementation of the aforementioned process according to the invention at a low temperature close to 4°C, that the lower the interfacial tension with water (below 10 mN / m), the rounder the resulting beads. A viscosity that is too low leads to sedimentation of the droplets and the formation of flattened beads (in the shape of "lenses"). A viscosity that is too high prevents draping or produces deformed beads (in the shape of "pears" or "rice grains").

[0027] The term "Prilling" used above refers to the addition of one solution to another in the form of drops, i.e., by "Dropping," as defined in section 4.1 of D. Ponselet's publication, Microencapsulation: Fundamentals, Methods and Applications, 2006, JP Blitz and VMGun'ko (eds.), Surface Chemistry in Biomedical and Environmental Science, 23-24. Preferably, the Prilling implemented corresponds to the so-called "Nozzle resonance" technique, as described in the aforementioned publication by D. Ponselet.

[0028] Advantageously, the Prilling of step c- of the process according to the invention is carried out with a syringe whose needle has an internal diameter D of 0.40 to 1.00 mm.

[0029] Advantageously, the prilling in step c of the process according to the invention is carried out using an electrostatic separator, preferably by applying a voltage of 3 to 7 keV (kiloelectronvolts). The inventors discovered by chance that such treatment, applied to the mixture obtained in step a and processed in step b, resulted in beads of very homogeneous sizes. The electrostatic separator is advantageously positioned at the point where the beads are formed and ideally at the outlet of the injector (or syringe needle): this configuration results in better separation. Preferably, the aqueous mixture of agar-agar and cellulose gum, optionally including at least one polyol used to manufacture the beads, comprises an organic acid such as a carboxylic acid of 1 to 12 carbons, preferably sorbic acid.

[0030] The present invention also relates to agar beads obtained according to the process as described above in the context of the present invention.

[0031] The present invention also relates to a cosmetic formulation comprising a gel with an aqueous phase and agar beads as described previously in the context of the invention. The aqueous phase preferably comprises: - a transparent gelling agent; - a suspender preferably consisting of sodium polyacrylate 6 (synthetic) taken from 0.4% to 1.5%, or a mixture of xanthan gum from 0.6% to 1% and / or gellan gum from 0.3% to 1% (natural ingredients); - a preservative; and - a pH adjuster; the gel may also contain various active ingredients, glycols etc.

[0032] Such an aqueous phase, called "external" because it is external to the beads and is the medium in which they are dispersed, ensures good dispersion and good stability of the beads, which remain well preserved in the state in which they were prepared.

[0033] Alternatively, the beads can be embedded in a vegetable oil; a mixture such as sunflower or rapeseed oil; or in a gelled coco-caprylate / caprate / caprylic / capric triglyceride ester with hydrogenated castor oil / sebacic acid copolymer, typically at a concentration of 2-10%; or even an alkane. Examples of suitable oils include mineral oils, such as paraffin oils, or synthetic oils, such as isopropyl myristate, coco-caprylate / caprate, ethylhexyl palmitate, and alkyl benzoates, or volatile or non-volatile silicone oils such as polydimethylsiloxanes (PDMS) and cyclodimethylsiloxanes or cyclomethicones, or fluorinated or fluorosilicone oils, as well as mixtures of all or some of these oils, possibly with all or some of those mentioned above.Advantageously, the vegetable oil can be chosen from among sweet almond, avocado, wheat germ, hazelnut, apricot kernel, castor, sesame, sunflower, rice, coconut, macadamia, safflower, jojoba, rapeseed, grapeseed, camellia, argan, cottonseed, borage, rosehip, evening primrose, olive, walnut, babassu, plum, coconut, chamomile, calendula, peppermint, hemp, lemon, palm, rosemary, sage, shea, soybean, sunflower, flaxseed, camelina, squalane (sugar cane oil), C10 to C30 alkanes, ester oils such as isopropyl myristate, cococaprylate, caprate, ethylhexyl palmitate, and C8-C10 triglyceride, ether oils such as dicaprylyl ether and their mixtures.

[0034] The present invention also relates to a cosmetic use of the cosmetic formulation according to the invention to moisturize the skin while perfuming it.

[0035] Other advantages may also become apparent to the person skilled in the art upon reading the examples below, illustrated by the attached figures, given for illustrative purposes.

[0036] Experimental section.

[0037] Protocol and equipment

[0038] For all the following examples, the protocol below is implemented as follows: Distilled water is heated to 85°C, then agar and cellulose gum are added (the quantities used are shown in the results table - Table 2), and possibly polyols. The mixture is stirred under Rayneri VMI with a deflocculator © (VMI assembly with M12 nut), maintaining the temperature at 85°C for 20 minutes at 850 rpm and C = 5 Ncm.

[0039] The preparation is then introduced into the Prilling machine and then cooled to 50°C.

[0040] The Prilling machine is the one developed by the company Synetude™ (Cognin, France), and has the following characteristics: - an injector; - an adjustable frequency measured in Hz (see table 2 of results); - an adjustable pressure measured in mBar (see table 2 of results); - an adjustable amplitude measured Vpp (see results table 2); and - a gelling bath with 2L of Isopropyl Myristate (CAS No. 110-27-0) under gentle stirring (magnetic stir bar), so as not to solidify the oil at 8°C.

[0041] The agar is dropped at approximately 45-70°C (above the gelling point of agar = 40°C) into cold oil at around 10°C, followed by rinsing and sieving the beads. The resulting beads are then dispersed and homogenized in an external gel, preferably aqueous. The thermal shock and incompatibility with the dropping medium facilitate bead formation.

[0042] An electrostatic separator is placed where the beads are formed; more specifically, the electrostatic separator is positioned at the injector of the prilling machine, which has a diameter of 0.17 to 0.41 mm. Depending on the desired bead size, a voltage of 3000 to 7000 volts is applied.

[0043] For measuring the average diameters of the beads, images are obtained with a LEICA® binocular stereomicroscope and analyzed using LAS EZ software. The samples to be analyzed are collected and placed on A microscope slide. The objective used is a 0.65x magnification objective; a graduated scale positioned near the slide allows for direct measurement by the observer. The images are then processed using Fiji software.

[0044] Measurement of resistance force in q / cm 2 : 1. Measuring devices and instruments -Rheometer manufacturer: Rheotech™; adjustment conditions: 1 cm cylindrical piston 2 ; sample base elevation velocity 2 cm / min -Stainless steel pot / capacity 2000 ml; -Plastic cup / inner diameter 60 mm x depth 65 mm -Incubator (air-cooled), set temperature 20°C. 2. 1.5% gel preparation -Weigh 9.0 g of sample. -Pour approximately 600 ml of modified (ion-exchanged) water into a 2000 ml stainless steel beaker and disperse it under mechanical stirring; -Boil under mechanical stirring for about 10 minutes until completely dissolved; -Adjust the final weight to 600g, remove from heat and pour into a measuring cup; -Leave to stand at room temperature for about 1 hour for the product to solidify. -incubator maintained at 20°C for at least 15 hours. 3. Measure the resistance strength of the jelly -Cut the exposed jelly horizontally with a knife; -Measure the gelation strength of the cut surface using a rheometer (Break when the piston penetrates approximately 1 cm into the gel); -Take the average value of two cups as the strength of the jelly.

[0045] Method for measuring viscosity - ISO 2555 standard (cosmetic standard method) Principle Measurement of the resistance to rotation of a mobile (spindle) immersed in the sample. Device Brookfield® type rotary viscometer Adapted mobiles (LV, RV, HA, HB) Thermostat or temperature-controlled bath Measurement conditions Temperature: 20 ± 0.5 °C or 25 ± 0.5 °C (to be specified) Defined rotation speed (e.g., 5, 10, 20 rpm) Stabilization time: generally 30 to 60 seconds And preferably by placing it at 25°C for 60 seconds on a Brookfield® viscometer with RV oscillator Simplified procedure Homogenize the sample (without bubbles) Bring to the measurement temperature Submerge the mobile up to the marker Choose the appropriate speed (torque between 10 and 90%) Read the viscosity once it has stabilized. Expression of the result Apparent viscosity in mPa-s (or cP) The measurements are taken at 25°C for 60s on a Brookfield® viscometer with RV oscillator.

[0046] Measuring the pH of a cosmetic product

[0047] Official standard

[0048] ISO 4316 - Cosmetics — Analytical methods — Determination of pH Principle Potentiometric measurement using a combined pH electrode. Calibrated pH meter equipment Electrode suitable for cosmetic products (semi-solids, emulsions) pH buffer solutions 4.00 / 7.00 (and 10.00 if necessary) Sample preparation Depending on the nature of the product: Aqueous products: direct measurement Creams / lotions / gels: Prepare a 10% w / w dispersion in distilled or deionized water ISO 4316 Procedure Calibrate the pH meter at 25°C Prepare the dilution if necessary Immerse the electrode in the sample Wait for stabilization Read the pH Measurement conditions Temperature: 25 ± 2 °C Electrode rinsed and dried between each measurement. 491 RESULTS The tested agar-agars that showed the best results are the reference ones. CS-303, CS-310 and CS-320; whose parameters are listed in Table 1 below:

[0050] Table 1.

[0051] Results table:

[0052] Table 2. Galenic formulation of agar beads; the oil used for the preparation of the beads is isopropyl myristate. The following compositions all contain 0.07% sorbic acid, 1.9% glycerol, and water in sufficient quantity (q.s.p.) to reach 100% by mass of bead. mass.

[0054] Tests 1, 2, 4, 8, 9, 11 and 12 are examples according to the invention, the other tests are counterexamples given only as an example.

[0055] The INCI name of Cellulose CM 2000S described in Table 2 is CELLULOSE GUM (INCI); that is, cellulose gum.

[0056] Measurement and Results for the average diameters of the balls according to the invention

[0057] The size of the beads is assessed by direct observation under a microscope equipped with a binocular magnifier. The equipment used is a LEICA® stereomicroscope, equipped with a data processing system implementing LAS EZ software, with image processing performed using Fiji.

[0058] The beads are collected using a spatula and placed on a microscope slide; observation is performed using the x0.65 objective. A graduated scale is placed next to each slide to allow for image processing.

[0059] The diameter measurement is performed on 43 balls for each sample.

[0060] Average sizes, standard deviations and CV% are deduced by dividing the standard deviation by the mean and multiplying by 100.

[0061] Four environments are evaluated with a water pH of 4, and concern: Medium 1: water; Medium 2: water and sorbic acid; Medium 3: water, sorbic acid and glycerin; Medium 4: isopropylmyristate+caprylic / caprictriglyceride; At the macroscopic level, all the beads have a spherical shape.

[0062] Table 3: Measurement results on day 8 at room temperature (TA) [00631 Table 4: Measurement results at J21 at room temperature

[0064] Table 5: Measurement results on day 21 at 50°C

[0065] Table 6: Measurement results at day 45 at room temperature

[0066] Table 7: Measurement results at day 45 at 50°C

[0067] SYNTHESIS AND ANALYSIS OF RESULTS Wilcoxon and Mann-Whitney): see Figures 1 to 4 (the asterisk means: "statistically different from condition J8"). The test is performed following the methods described in Frank Wilcoxon, “Individual comparisons by ranking methods”, Biometrics Bulletin, vol. 1, no. 6, 1945, p. SO-83 and Henry B. Mann et al. , “On a test of whether one of two random variables is stochastically larger than the other”, Ann. Math. Statistics, vol. 18, no. 1, 1947, p. 50-60.

[0069] Results : Medium 1 (water): statistical analysis shows us a slight significant increase in the size of the beads at J 21 at 50°C, at J 45 at TA and at 50°C compared to the size of the beads at J 8; Medium 2 (water - sorbic acid): slightly greater variations are observed in this medium compared to the other media. Statistical analysis shows a slight but significant increase in bead size at J 21 and J 45 at TA and 50°C; Medium 3 (water - sorbic acid - glycerin): statistical analysis shows a slight significant increase in the size of the beads at J 21 and J 4 and at TA and at 50°C; Medium 4 (isopropyl myristate, caprylic / capric triglyceride): bead size is more stable than in the other media. Statistical analysis shows a slight increase in bead size after 45 days at room temperature.

Claims

Demands

1. Agar beads comprising a material extending from the center of the beads to the surface of the beads, said material comprising agar-agar and cellulose gum.

2. Agar beads according to claim 1, wherein the agar-agar is an agar-agar having a tensile strength of 10 to 400 g / cm² 2 , and preferably 150 to 250 g / cm² 2 at 1.5%.

3. Agar beads according to any one of claims 1 or 2, wherein the agar-agar is at a pH of 5 to 8, and preferably 6 to 7.

4. Agar beads according to any one of claims 1 to 3, wherein the agar-agar has a viscosity of 2 to 5 mPa.s, and preferably 3 to 4 mPa.s at 80°C.

5. Agar beads according to any one of claims 1 to 5, wherein the mass percentage of agar-agar is from 0.25 to 2.25%, and preferably from 0.50 to 2.00%, taken in relation to the total mass of the bead.

6. Agar beads according to any one of claims 1 to 6, wherein the mass percentage of cellulose gum is from 0.05 to 5.50% preferably from 0.5 to 5%, taken in relation to the total mass of the bead.

7. Agar beads according to any one of claims 1 to 7, wherein the average diameter of the beads is less than or equal to 5000 pm and preferably the average diameter is from 1500 pm to 2000 pm.

8. Agar beads according to any one of claims 1 to 8, comprising at least one element selected from a preservative, preferably a polyol, a solubilizer, a fat, a mother-of-pearl, a pigment, a colorant such as titanium or a vegetable oil.

9. Agar beads according to any one of claims 1 to 9, said beads comprising a perfume.

10. A process for preparing agar beads according to any one of claims 1 to 9, comprising the following steps: a- preparing an aqueous mixture of agar-agar and gum arabic cellulose possibly comprising at least one polyol; b- bring the mixture obtained in step a- to a temperature of 85 to 90 °C; c- allow the mixture obtained in step b- to cool to a temperature of 40 to 70 °C, then pour by drop, preferably by implementing a Prilling, said mixture into an oily phase maintained at a temperature below 35 °C and preferably from 4 to 25 °C; and d- sieve the suspension obtained in step c- and possibly rinse the beads obtained with possibly purified water.

11. A process according to claim 10, wherein the oily phase of step c- comprises an oil selected from vegetable oil, and preferably selected from castor oil, a cocoglyceride, palmitic oil, isopropyl myristate and caprylic / capric triglyceride.

12. A method according to any one of claims 10 or 11, wherein the prilling in step c- is a prilling carried out with a syringe whose needle has an internal diameter D of 0.40 to 1.00 mm.

13. Cosmetic formulation comprising a gel having an aqueous phase and agar beads according to any one of claims 1 to 9.

14. Cosmetic use of the cosmetic formulation according to claim 13 to moisturize the skin by perfuming it.

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