阅读说明：本技术 抗微生物颗粒组合物和包含其的个人护理组合物 (Antimicrobial particulate compositions and personal care compositions comprising the same ) 是由 R·米特拉 G·莫拉里塔兰 A·普拉马尼克 S·萨卡尔 S·达斯 于 2019-03-01 设计创作，主要内容包括：本发明涉及抗微生物颗粒组合物及其制备方法。本发明也涉及包含所述抗微生物颗粒组合物的个人护理组合物。本发明在以生产规模制备时确保期望的功效,同时显示出组合物的期望的浅色外观。(The present invention relates to antimicrobial particulate compositions and methods of making the same. The present invention also relates to personal care compositions comprising the antimicrobial particulate composition. The present invention ensures the desired efficacy when prepared on a production scale while exhibiting the desired light colored appearance of the composition.)

1. An antimicrobial particulate composition comprising:

i.0.05% to 3% by weight of antimicrobial metal particles immobilized on a material,

ii.97 to 99.95% by weight of calcite having a particle size above 8m²Specific surface area per gram;

wherein the antimicrobial metal particles are silver or copper nanoparticles.

2. The antimicrobial particulate composition of claim 1 wherein the antimicrobial metal particles are silver nanoparticles.

3. A personal care composition comprising:

(i) from 5% to 85% by weight of a surfactant, and

(ii)0.1 to 5% by weight of an antimicrobial particulate composition according to claim 1 or 2.

4. The personal care composition of claim 3, wherein the surfactant is an anionic surfactant, preferably a soap.

5. A method for preparing an antimicrobial particulate composition, the method comprising the steps of:

i. mixing 10-50 wt% of an aqueous dispersion of calcite in water with 0.01-10% by weight of the calcite of an aqueous solution of a reducing agent, the calcite having a height above 8m²A specific surface area per gram and a particle size in the range of 1 to 10 microns;

(ii) increasing the temperature of the mixture of step (i) to a temperature in the range of 60 ℃ to 90 ℃;

(iii) adding 0.01 to 10% by weight of the calcite of a water-soluble metal salt to the mixture of step (ii), wherein the water-soluble metal salt is a water-soluble salt of silver or copper;

(iv) separating water from the product of step (iii) to produce a wet cake; and

v. drying the wet cake.

6. The method of claim 5, wherein the water-soluble metal salt is a water-soluble salt of silver.

7. The method of claim 6, wherein the water soluble salt of silver is selected from silver nitrate or silver acetate.

8. The process of any one of claims 5 to 7, wherein the reducing agent is selected from water-soluble salts of carboxylic acids having 1-4 carboxylic acid groups.

9. The method of claim 8, wherein the reducing agent is selected from sodium acetate, sodium oxalate, trisodium citrate, or disodium ethylenediaminetetraacetic acid.

10. A method of providing enhanced leaching of antimicrobial metals into cleaning solutions comprising dissolving/dispersing the composition of any one of claims 1 to 4 in water.

11. A method of providing an antimicrobial effect on a topical surface of the human or animal body comprising the steps of applying a composition as claimed in any one of claims 1 to 4 to a desired surface and optionally rinsing the surface substantially free of the composition with water.

12. The method of claim 11, wherein the rinsing step is performed 10 seconds to 5 minutes after applying the composition onto the desired surface.

13. An antimicrobial particulate composition obtainable by the method of any one of claims 5 to 9.

Technical Field

The present invention relates to antimicrobial particulate compositions and methods of making the same. The present invention also relates to personal care compositions comprising the antimicrobial particulate composition. The present invention is particularly advantageous in that even when the process of preparing the antimicrobial particulate composition is scaled up to production scale, the antimicrobial particulate composition still imparts the desired effect while imparting enhanced leaching (leach) of the antimicrobial metal species while ensuring that the antimicrobial particulate composition and personal care compositions prepared therefrom exhibit the desired light color.

Background

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

Antimicrobial metal particles such as silver or copper nanoparticles are broad spectrum antimicrobial materials used for different purposes, including water purification and other hygiene related products. However, these metal nanoparticles are known to be toxic and cannot be used as such in compositions for human use, nor in high concentrations. They also have an impact on the environment.

In co-pending application WO2016020168(Unilever) is disclosed a method of preparing antimicrobial particle compositions in which metal nanoparticles are immobilized in an inorganic porous material, and of incorporating these particles into personal care or hygiene compositions. The antimicrobial particulate composition comprises antimicrobial metal particles immobilized on an inorganic porous material selected from zinc oxide, magnesium hydroxide or calcium carbonate. The object of the above invention is to form a light-colored product while at the same time obtaining good antimicrobial properties.

One of the modes of operation of the invention disclosed in WO2016020168 is the use of vaterite (a form of calcium carbonate) as a fixing agent. While desirable properties (light color, good antimicrobial efficiency, etc.) can be obtained when using vaterite to make antimicrobial compositions using the process on a laboratory scale (up to several grams), the efficacy cannot be repeated when scaling up the process to production scale conditions of about 100kg of material. The product thus prepared in the production plant does not show the desired leaching of the metal species required to obtain the desired antimicrobial activity. The reaction is kinetically driven, and the inventors contemplate that the instability exhibited upon scale-up is much higher due to the long reaction times inherent in production-scale processes as compared to laboratory-scale processes.

The inventors have determined by further experiments on a production scale that the kinetics of the reaction can be modified by using certain polymers, such as crystal habit modifiers, but have found that the products so prepared have the problem of low antimicrobial activity. The present inventors hypothesize that this low antimicrobial activity is due to the efficacy of the antimicrobial metal species preferentially reacting with the polymer, thereby inhibiting the intercalation of the metal species onto the inorganic matrix.

The inventors then tried many different strategies to solve this problem and finally obtained a solution by using a specific polymorphic form of calcium carbonate as fixative. The use of this particular polymorph (i.e. calcite) alone is not sufficient to solve all of the above problems. In order to obtain the desired leaching of the metal species and thus the desired antimicrobial efficacy with the antimicrobial particulate composition prepared on a production scale, the inventors have determined that it is only possible to obtain a product that solves all the above problems when calcite has a specific surface area higher than a certain value. Surprisingly, not only the above problems are solved, but the product thus obtained has the desired light-coloured appearance.

It is therefore an object of the present invention to provide a light colored antimicrobial particulate composition having good antimicrobial properties when prepared under production scale conditions.

Brief description of the invention

According to a first aspect of the present invention there is provided an antimicrobial particulate composition comprising:

(i)0.05 to 3% by weight of antimicrobial metal particles immobilized on a material,

(ii)97 to 99.95% by weight of calcite having a particle size higher than 8m²Specific surface area per gram;

wherein the antimicrobial metal particles are silver or copper nanoparticles. According to another aspect of the present invention, there is provided a personal care composition comprising:

(i) from 5% to 85% by weight of a surfactant, and

(ii) from 0.1 to 5% by weight of an antimicrobial particulate composition according to the first aspect of the present invention.

According to yet another aspect of the present invention, there is provided a method for preparing an antimicrobial particulate composition, the method comprising the steps of:

(i) mixing 10-50 wt% of a mixture having a particle size of more than 8m²An aqueous dispersion in water of calcite having a specific surface area per gram and a particle size in the range of 1 to 10 microns with an aqueous solution of 0.01-10% reducing agent by weight of the calcite;

(ii) (ii) increasing the temperature of the mixture of step (i) to a temperature in the range of from 60 ℃ to 90 ℃;

(iii) (iii) adding 0.01 to 10% by weight of the calcite of a water-soluble metal salt to the mixture of step (ii), wherein the water-soluble metal salt is a water-soluble salt of silver or copper;

(iv) (iv) separating water from the product of step (iii) to produce a wet cake (wet cake); and

(v) the wet cake was dried.

Yet another aspect of the invention relates to a method of providing enhanced leaching of antimicrobial metals into cleaning solutions comprising dissolving/dispersing a composition according to the first or second aspect of the invention in water.

Yet another aspect of the present invention relates to a method of providing an antimicrobial effect on a topical surface of a human or animal body comprising the steps of applying the composition of the first or second aspect to the desired surface and optionally rinsing said surface with water to be substantially free of said composition.

According to yet another aspect of the present invention there is provided an antimicrobial particulate composition obtainable by the method of the present invention.

Detailed Description

These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the invention may be used in any other aspect of the invention. The word "comprising" is intended to mean "including", but not necessarily "consisting of. In other words, the listed steps or options need not be exhaustive. It should be noted that the examples given in the following description are intended to illustrate the present invention, and are not intended to limit the present invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about". Numerical ranges expressed in "x to y" format should be understood to include x and y. When multiple preferred ranges are described in the format "x to y" for a particular feature, it is to be understood that all ranges combining the different endpoints are also contemplated.

The present invention relates to an antimicrobial particulate composition comprising an immobilized enzyme having a height of greater than 8m²Antimicrobial metal particles on calcite per g of specific surface area.

The antimicrobial metal particles are silver or copper particles, preferably silver or copper nanoparticles, most preferably silver nanoparticles. The term "metal particles" as used herein refers to particles of elemental metal and does not include particles of metal salts, metal oxides or other metal compounds. The antimicrobial metal particles are included in an amount of 0.05 to 3%, preferably 0.5 to 1.5%, by weight of the antimicrobial particle composition.

Antimicrobial particulate compositions comprising particles having a particle size greater than 8m²Calcite with a specific surface area per gram. The specific surface area is preferably higher than 12m²In g, more preferably above 16m²(ii) in terms of/g. Calcite polymorphs are a particularly important ingredient of antimicrobial particulate compositions because it can be seen that this particular polymorph is stable at high temperatures during the process of embedding the antimicrobial metal particles therein. This stability was not observed when other polymorphs of calcium carbonate, such as vaterite or aragonite, were used. Furthermore, it is preferred that the calcite used is pure calcite. Mixtures of calcite with other polymorphs such as vaterite or aragonite (argonite) are often unsuitable for the purposes of the present invention. Preferably, the calcium carbonate is at least 95% having a particle size above 8m ²Calcite with a surface area per gram, more preferably at least 98%, still more preferably at least 99% of the surface area is higher than 8m²Per g of calcite. Ideally, it is pure calcite, i.e. 99.9% or even 100% of the surface area is higher than 8m²Per g of calcite. Furthermore, only when calcite of high surface area (specific surface area higher than 8 m) is used²/g) and less efficacy when using calcium carbonates with low surface area, such as ground natural chalk (FGNC) or Precipitated Calcium Carbonate (PCC). Furthermore, when calcium carbonate is reacted with certain phosphates, it is found that there is a large amount of calcium phosphate in the matrix and is therefore not suitable for use in the present invention.

Calcite is included at 97 to 99.95%, preferably 98.5 to 99.5% by weight of the antimicrobial particulate composition. Calcite having a particle size in the range of 1 to 10 microns, more preferably in the range of 2 to 5 microns, is preferably used.

According to the invention, the specific surface area is measured using the following method:

the Brunauer-Emmett-Teller (BET) method was used to quantify the specific surface area of calcite. The nitrogen adsorption-desorption isotherm was recorded at 77K. The specific surface area is calculated using standard BET equations using pressures in the range of 0.05 to 0.3 (P/Po).

Particle size and calcite morphology were characterized using Field Emission Scanning Electron Microscopy (FESEM). Ultra55(Zeiss) was used for FESEM imaging and operated at an electron voltage of 2 kV. XRD was performed to characterize the crystal structure of calcium carbonate.

Generally, when referring to immobilized antimicrobial particles or immobilized antimicrobial metal particles or immobilized metal nanoparticles or immobilized materials for a particular metal such as silver or copper, it refers to the antimicrobial particle composition of the present invention. The phrases "antimicrobial metal particles" and "metal species" are used interchangeably in this specification.

The present invention also relates to personal care compositions comprising the antimicrobial particulate composition and a surfactant. The personal care composition comprises from 5% to 85%, preferably from 15 to 40% by weight of surfactant. The antimicrobial particulate composition of the present invention is included in an amount of from 0.1 to 5%, preferably from 0.25 to 4%, by weight of the personal care composition.

The surfactant is selected from one or more of the classes of anionic, nonionic, cationic or zwitterionic surfactants, preferably from anionic surfactants. The anionic surfactant is preferably soap. The term soap refers to salts of fatty acids. Preferably, the soap is C ₈To C₂₄Soaps of fatty acids, more preferably C₁₀To C₁₈Soaps of fatty acids. It is particularly preferred that the soap comprises C in an amount of at least 40% by weight of the total soap content₈-C₁₄Soaps of fatty acids, more preferably at least 50 wt%, and most preferably at least 70 wt%. It is also preferred that when the personal care composition of the present invention is formulated as a cleansing bar, it comprises up to 60% by weight of C of the total soap content₁₆-C₂₂Soap of fatty acids, preferably up to 50 wt.%, and most preferably up to 30 wt.%.

The cation may be an alkali metal, alkaline earth metal or ammonium ion, preferably an alkali metal. Preferably, the cation is selected from sodium or potassium. The soap may be saturated or unsaturated. Saturated soaps are superior to unsaturated soaps in terms of stability. The oil or fatty acid may be of vegetable or animal origin.

Soaps can be obtained by saponification of oils, fats or fatty acids. The fat or oil typically used to prepare the soap bar may be selected from tallow, tallow stearin, palm oil, palm stearin, soybean oil, fish oil, castor oil, rice bran oil, sunflower oil, coconut oil, babassu oil and palm kernel oil. The fatty acid may be derived from coconut, rice bran, groundnut, tallow, palm kernel, cotton seed or soybean.

The fatty acid soaps may also be synthetically prepared (e.g., by oxidation of petroleum or by hydrogenation of carbon monoxide by the fischer-tropsch process). Resin acids, such as those present in tall oil, may also be used. Naphthenic acid may also be used. The soap is preferably included at from 5% to 85%, preferably from 10% to 85%, more preferably from 25% to 75% by weight of the personal care composition.

The personal care compositions of the present invention may be in the form of a liquid, gel, cream, or solid composition. It is preferably in the form of a solid composition, more preferably in the form of a shaped solid such as a bar. The personal care composition of the present invention may be a leave-on or rinse-off composition, preferably it is a rinse-off composition. Leave-on compositions refer to compositions that are applied to the desired topical surface of the human body and remain thereon to produce the desired effect and are not washed off until the next shower or bath. Thus, leave-on products are retained on topical surfaces for several hours, and possibly up to a full day. The rinse-off product has a sufficient amount of surfactant included therein for cleansing the desired topical surfaces, such as the whole body, hair and scalp or face. It is applied to a topical surface and left thereon for only a few seconds or minutes and then washed off with a large amount of water. The personal care compositions of the present invention are preferably rinse-off compositions.

The inventors have determined that when the antimicrobial particulate composition of the present invention is included in a surfactant (e.g. soap) based composition, the antimicrobial effect occurs in a very short time, for example, on the order of less than 5 minutes, preferably less than 2 minutes, even more preferably less than one minute, and in many cases as low as 10 seconds. Occasionally, rinse-off compositions contain surfactants for cleaning action, wherein the surface is washed with the composition for only such a short period of time that not only is the surface cleaned of all unwanted soils, but the benefits of antimicrobial activity imparted by the compositions of the present invention are obtained within that short period of time.

When present in the form of a transparent soap bar, the personal care compositions of the present invention may include a water soluble organic solvent. This is preferably selected from polyols, hydrotropes or mixtures thereof. The water-soluble organic solvent is preferably in the range of 20 to 45 wt%, more preferably in the range of 25 to 40 wt%, most preferably in the range of 30 to 40 wt%, based on the weight of the composition.

Preferred cleansing bars comprise 20% to 45% by weight of the polyol, based on the weight of the composition. Preferred polyols include one or more of glycerol, sorbitol, propylene glycol or polyethylene glycol. Mixtures are generally used. More preferred bars comprise 25 to 40 wt% polyol, most preferred bars comprise 30 to 40 wt% polyol. A polyhydric alcohol (polyol) such as propylene glycol can be used as a diluent to dilute an otherwise thick mixture of caustic soda and fatty acids.

Hydrotropes may also be included in the personal care compositions of the present invention. Hydrotropes include, but are not limited to, sodium cumene sulfonate, sodium toluene sulfonate, sodium xylene sulfonate, and sodium alkyl aryl sulfonate, their derivatives, and combinations thereof.

Electrolytes may optionally be included in the personal care compositions of the present invention. They are preferably included in the range of 3 to 20%, more preferably in the range of 3.5 to 15%, most preferably in the range of 4 to 10% by weight of the composition. Preferred electrolytes of the present invention include sodium sulfate, sodium chloride, sodium acetate, sodium citrate, potassium chloride, potassium sulfate, sodium carbonate and other mono-or di-or tri-salts of alkaline earth metals, more preferred electrolytes are sodium chloride, sodium sulfate, sodium citrate, potassium chloride, and particularly preferred electrolytes are sodium chloride, sodium sulfate and sodium citrate and combinations thereof. For the avoidance of doubt, it may be clear that the electrolyte is a non-soap material.

Sunscreens may optionally be present in the personal care composition. When opacifiers are present, the cleansing bar is typically opaque. Examples of opacifiers include titanium dioxide, zinc oxide, and the like. A particularly preferred opacifier that may be used when an opaque soap composition is desired is a 20% solution of ethylene glycol monostearate or distearate, such as sodium lauryl ether sulfate. An optional opacifier is zinc stearate.

The product may take the form of a watery transparent (i.e. transparent soap) in which case it will not contain an opacifier, or alternatively it may take the form of an opaque liquid soap containing an opacifier (as herein defined).

Preferred personal care compositions in the form of cleansing bars comprise from 20 to 40 wt% water, more preferably from 20 to 35 wt% and most preferably from 22 to 30 wt% water, based on the weight of the composition. More or less water may adversely affect clarity.

Preferred soap bars of the invention have a pH of from 8 to 11, more preferably from 9 to 11. Preferred personal care compositions in the form of bars may comprise up to 30 wt% benefit agent. Preferred benefit agents are moisturizers, emollients, sunscreens and anti-aging compounds. The agent may be added at a suitable step during the process of making the strip. Some benefit agents may be introduced as large domains (macrodomains).

Other optional ingredients such as antioxidants, fragrances, polymers, chelating agents, colorants, deodorants, dyes, emollients, moisturizers, enzymes, foam boosters, bactericides, additional antimicrobials, foaming agents, pearlescers, skin conditioners, stabilizers, superfatting agents, sunscreens may be added in suitable amounts in the process of the present invention. Preferably, the ingredients are added after the saponification step and before filtration. Preferably sodium metabisulphite, ethylenediaminetetraacetic acid (EDTA), borax or vinyl hydroxy diphosphonic acid (EHDP) is added to the formulation.

The process of the present invention for preparing an antimicrobial particulate composition comprises the steps of:

i. mixing 10-50 wt%, preferably 20-40 wt% of the mixture with a specific surface area higher than 8m²Aqueous dispersion of calcite in water having a particle size of 1 to 10 μm/g and process for its preparationAn aqueous solution of 0.01-10%, preferably 0.1 to 5%, by weight of the calcite, of a reducing agent;

(ii) increasing the temperature of the mixture of step (i) to a temperature in the range of from 60 ℃ to 90 ℃, preferably from 65 to 85 ℃;

(iii) adding 0.01% to 10%, preferably 0.1% to 5%, by weight of the calcite, of a water-soluble metal salt to the mixture of step (ii);

(iv) separating the product of step (iii) from water to produce a wet cake; and

v. drying the wet cake.

The process according to the invention preferably does not require a calcination step, and preferably the process does not comprise a calcination step.

The reducing agent used in the process of the invention is preferably selected from water-soluble salts of carboxylic acids having from 1 to 4 carboxylic acid groups. More preferably it is selected from sodium acetate, sodium oxalate, trisodium citrate or disodium edetate. Preferably trisodium citrate is included as reducing agent. The reducing agent is preferably added to the process as an aqueous solution, preferably at 0.1 to 10%, more preferably 0.5 to 5% by weight of the solution.

It is highly preferred that the aqueous dispersion of calcite and the aqueous solution of the reducing agent are mixed prior to addition of the metal salt solution. During this process, the pH of the reaction medium is preferably maintained at a pH greater than 5, more preferably in the range of 6-8.

The water soluble metal salt is selected from water soluble salts of silver or copper. Preferably, a water-soluble metal salt is added as an aqueous solution.

Preferably, the water soluble silver salt is selected from silver nitrate or silver acetate. The concentration of the aqueous solution of the water-soluble metal salt is preferably in the range of 0.1 to 10%, more preferably 0.5 to 5% by weight of the aqueous solution. Silver nitrate is preferably used as the water-soluble salt of silver.

Preferably, the water-soluble copper salt is selected from copper (II) sulfate, copper (II) nitrate, copper (II) chloride or copper (II) acetate. Preferably, copper (II) nitrate is used as the water-soluble copper salt.

The invention also relates to a method of providing enhanced leaching of antimicrobial metals into a cleaning solution comprising the step of dissolving/dispersing the composition of the first or second aspect in water. The leaching rate of the antimicrobial metal species according to the invention is higher than the leaching rate obtained when the metal is immobilized on any other polymorph of calcium carbonate or on any other inorganic substrate, such as zinc oxide, magnesium oxide, titanium dioxide, etc.

Yet another aspect of the present invention provides a method of providing an antimicrobial effect on a topical surface of a human or animal body comprising the steps of applying a composition of the first or second aspect to a desired surface and optionally rinsing said surface with water to be substantially free of said composition. By "substantially free of said composition" is meant that the composition is not perceptible to the touch of a human hand. The composition of the first aspect of the present invention is a granular composition and is generally perceived as a powdery, rough or grainy feel when touched by the human hand. The composition of the second aspect of the present invention is a personal care composition which comprises a surfactant and which is generally perceived as a greasy (soapy) or slippery sensation when touched by the human hand. Such a tactile sensation is not perceived by a human hand when the surface is substantially free of the composition. Preferably, the composition is applied to the surface after dilution with water. The rinsing step is optional, but preferred. The rinsing step is preferably performed within 5 minutes, preferably within two minutes, further more preferably within one minute, even further preferably within 30 seconds, and in some cases may be performed within 10 or 15 seconds of applying the composition. The method is preferably non-therapeutic or cosmetic.

The present invention also relates to an antimicrobial particulate composition obtainable by the method of the present invention. Preferably, it also relates to an antimicrobial composition obtained by the method of the invention.

The invention will now be illustrated with reference to the following non-limiting examples.

Examples