EP4065065A1

EP4065065A1 - Antimicrobial compositions comprising modified clay and copolymers

Info

Publication number: EP4065065A1
Application number: EP20796586.4A
Authority: EP
Inventors: Shanthi APPAVOO; Anindya Dasgupta; Srikala KUMARAN
Original assignee: Unilever Global IP Ltd; Unilever IP Holdings BV
Current assignee: Unilever Global IP Ltd; Unilever IP Holdings BV
Priority date: 2019-11-28
Filing date: 2020-10-27
Publication date: 2022-10-05
Also published as: BR112022007844A2; CL2022001361A1; WO2021104780A1; CN114746063A

Abstract

The present invention is in the field of antimicrobial compositions, e.g. for personal care. In particular, the invention relates to antimicrobial compositions for oral care, such as toothpastes, comprising antimicrobial particles and specific copolymers. The invention further relates to the uses and methods of the antimicrobial compositions of the invention.

Description

ANTIMICROBIAL COMPOSITIONS COMPRISING

MODIFIED CLAY AND COPOLYMERS Field of the Invention

The present invention is in the field of personal care. In particular, the invention relates to an antimicrobial composition that can be used, for instance, in oral care. The antimicrobial compositions comprise modified clay and copolymers. The invention further relates to uses of the antimicrobial composition.

Background of the Invention

Hygiene and appropriate personal care can prevent and treat a number of diseases caused by micro-organisms. A useful instrument to facilitate and improve hygiene includes personal care compositions. The most effective personal care compositions serving this purpose include antimicrobial components that can decrease the microbial count on skin and mucosa surfaces. For instance, antimicrobial compositions in deodorants reduce or prevent the growth of microorganisms that generate malodor or that promote the decomposition of body oils into odiferous fatty acids. Similar principles apply to shampoos, shower gels, tooth pastes, hand and body washes and other examples of personal care compositions comprising antimicrobial compositions.

One of the most important aspects of personal care is oral health. Cavities, tartar, gum diseases e.g. gingivitis, plaque and halitosis are diseases (or conditions resulting from or that may lead to diseases) in the oral cavity that can be easily prevented or treated by adequate oral hygiene. These diseases and conditions are not only of importance from a medical perspective but also from the cosmetic point of view as they may impair one’s smile appearance (such as teeth yellowing or bad breath, that not necessarily has a pathological origin). In any case, an unhealthy and/or impaired oral condition may affect people’s social activities, sometimes leading to low self-esteem. As much as it is relevant for the oral health of human subjects, oral care is also of increasing importance in the veterinary industry, either for pets or large animals.

Oral diseases and cosmetically impairing oral conditions develop from the formation of biofilm on the surface of teeth. Oral biofilm affects the cosmetic appearance for it facilitates teeth discoloration and/or staining. Oral biofilm is formed by attachment of acquired pellicle, which is a thin protein- containing film derived from salivary glycoproteins, to a clean tooth surface. The pellicle allows bacteria adhesion from so-called pioneer species, such as Actinomyces spp, Streptococcus spp, Haemophilus spp, Capnocytophaga spp, Veillonella spp, and Neisseria, to the tooth surface. This early stage of biofilm formation can be easily reversed. However, if not removed, the pioneer bacteria will enable the subsequent attachment of bacterial species such as Fusobacterium nucleatum, Treponema spp, Tannerella forsythensis, P. gingivalis, Aggregatibacter actinomycetemcomitans, etc., that are related to the formation of plaque, tartar, gum diseases, etc.

Halitosis may be a symptom of oral diseases as it often indicates the presence of pathogens causing e.g. cavities and gingivitis. However, halitosis is not always connected to a medical condition. Bad breath, or mouth malodor, may be caused, for instance, by some medicaments, excessive caffeine consumption or reduced saliva production (dry mouth). Non pathological halitosis can be prevented or controlled with oral care compositions such as mouthwashes, chewing gums, toothpastes, breath tablets, and other products that ensure oral cleaning and provide a fresh breath.

Many oral care compositions have been proposed and some are even marketed to tackle the above mentioned problems. In spite of these, there still is a need among consumers to tackle the above problems and they are always on the lookout for solutions that involve less or no actives that are considered to be of harsh chemical origin. Thus, compounds that are generally considered to be inert like naturally occurring clays or polymer whether of natural or synthetic origin are often accepted by consumers. The present inventors in search of such solutions, through their inherent knowledge of such materials and through extensive experimentation arrived at a combination of a modified clay (which they have patented and is published as WO 2011/036031) and specific copolymers which provides synergistic anti-biofilm efficacy.

WO 2011/036031 A1 describes a bipolar antimicrobial particle for use in laundry detergent compositions, fabric conditioners, personal care and cosmetic compositions and a process for making the same. The antimicrobial particle described therein comprises a modified clay particle with an antimicrobial group attached thereto. The examples describe the preparation of the modified clay particles and its antimicrobial activity, in particular on fabrics. Oral care compositions comprising copolymers have also been reported. EP0341660 (Goodrich, 1989) discloses oral compositions and a method for inhibiting dental calculus characterized by the presence of a flouride source, a dental abrasive, and an anticalculus agent of at least two polymers selected from homopolymers of a carboxy monomer and copolymers containing at least 30% of said carboxyl monomer, said carboxyl monomer is selected from monounsaturated carboxylic acids of 3 to 5 carbons, anhydrides thereof, salts thereof, and mixtures of said carboxyl monomers.

W013187918 (P&G) discloses a liquid, cleaning and/or cleansing composition comprising biodegradable abrasive cleaning particles which comprises biodegradable polyester material selected from a large group of copolymers.

EP0525913 (Colgate, 1993) discloses a toothpaste or dental gel composition containing an amount of a synthetic linearly viscoelastic cross-linked polymeric thickening agent, especially a cross-linked methyl vinyl ether/maleic anhydride copolymer, effective to render the composition linearly viscoelastic, and a method of promoting oral hygiene by applying an effective amount of the composition to dental surface.

In spite of the above disclosed art, there remains a need for antimicrobial compositions with further improved antimicrobial activity, in particular for use in personal care such as compositions for oral care.

Summary of the Invention

The present inventors have surprisingly found that modified clay particles comprising antimicrobial components present synergistic antimicrobial activity when used in a composition further comprising select copolymer.

Accordingly, in a first aspect, the invention relates to an antimicrobial composition comprising: a) a modified clay particle comprising an antimicrobial compound, the modified clay particle comprising:

(i) an asymmetric 1:1 or 2:1:1 clay particle comprising alternating tetrahedral and octahedral sheets terminating with a tetrahedral sheet at one external surface plane and an octahedral sheet at another external surface plane, and

(ii) at least one orally acceptable antimicrobial compound attached to the coordinating cation on an external surface plane of the clay particle; and b) a polymeric compound selected from (i) a copolymer of styrene sulfonic acid and maleic acid; (ii) poly(ethylene succinate); (iii) poly(ethylene adipate); (iv) phosphino carboxylic acid copolymer; or (v) carboxylate sulfonate terpolymer.

In a second aspect, the invention relates to a composition of the first aspect for use in the prevention or treatment of a disease of a mammal, preferably for use in the prevention or treatment of a disease in the oral cavity selected from the group comprising caries, tartar, dental plaque, gum diseases, and combinations thereof.

In a third aspect, the invention relates to a composition of the first aspect for use in the removal of oral biofilm in a mammal subject.

In yet another aspect is claimed a non-therapeutic method of treating the skin and/or oral cavity of a mammal, the method including the step of contacting the skin and/or oral cavity of a mammal with the antimicrobial composition of the first aspect

Yet another of the invention is related to use of a composition of the invention, for reducing body malodor, preferably mouth malodor, and/or for reducing oral biofilm formation and/or for reducing tooth discoloration, in a mammal

Detailed Description of the Invention

Modified particle

The composition according to the invention comprises a modified clay particle comprising an antimicrobial compound, the modified clay particle comprising an asymmetric 1:1 or 2:1:1 clay particle having alternating tetrahedral and an octahedral sheets terminating with a tetrahedral and an octahedral sheet at exterior surface planes. Particle of 1:1 clay is preferred.

The particle is prepared from a precursor with bipolar topospecific characteristics. Any chemical reaction or series of reactions wherein an antimicrobial compound is attached selectively to coordinating cations on the exterior plane of either the tetrahedral or the octahedral surface plane of asymmetric clay can be used to prepare the bipolar particle comprising an antimicrobial compound used in the present invention. In order to obtain a true bipolar antimicrobial particle, it is preferred that the reaction is selective to only one of the exterior planes. By selective is meant that more than 50% of the total antimicrobial compound is present on one of the exterior planes, preferably more than 75%, more preferably than 80%, still more preferably than 90%, even more preferably than 95%, or even more than 99%. The bipolar particle comprising an antimicrobial compound used in the composition according to the invention can be prepared, e.g. by the process described in WO 2011/036031, incorporated herein by reference.

According to the present invention, preferred 1:1 clays include kaolinite and serpentine subgroups of minerals. The species included within the kaolinite subgroup include but are not limited to kaolinite, dickite, halloysite and nacrite. The species within the serpentine subgroup include but are not limited to chrysolite, lizardite, and amesite.

According to the present invention, preferred 2:1:1 clays include chlorite group of minerals. Chlorite is sometimes wrongly referred to as 2:2 clay by some mineralogists. The chlorite comprises tetrahedral-octahedral-tetrahedral sheets like 2:1 clays, with an extra weakly bound brucite like layer between tetrahedral layers.

The tetrahedral sheet preferably comprises coordinating tetrahedral cations of silicon. The tetrahedral sheet may also comprise isomorphously substituted coordinating tetrahedral cations which are not silicon. Isomorphously substituted coordinating tetrahedral cations include, but are not limited to, cations of aluminum, iron or boron.

The octahedral sheet preferably comprises coordinating octahedral cation of aluminum. The octahedral sheet may also comprise isomorphously substituted coordinating octahedral cations which are not aluminium. Isomorphously substituted coordinating octahedral cations include cations of magnesium or iron.

The at least one antimicrobial compound is attached to the coordinating cation on an external surface plane of the clay particle. Preferably, no antimicrobial compound is attached to coordination cations of non-exterior tetrahedral or octahedral plane or on the interior side of the surface sheets. The antimicrobial compound may be attached to coordinating cations on the exterior side of the tetrahedral sheet or to the coordinating cations on the exterior side of the octahedral sheet. Preferably, the at least one antimicrobial compound is attached to the coordinating cations on the external surface of the octahedral surface plane.

The at least one antimicrobial compound may be attached to coordinating cations on the exterior side of the same surface sheet or on the exterior side of each of the tetrahedral and the octahedral surface sheets. The antimicrobial compounds may be the same or different. Preferably, the antimicrobial compound attached to the coordinating cations on the exterior side of the tetrahedral surface sheet is preferably not identical to the compound attached to the coordinating cations on the exterior side of the octahedral surface sheet.

Preferably, the modified clay particle has a clay : antimicrobial compound weight ratio is between 1:0.001 and 1:0.1, more preferably between 1:0.01 and 1:0.05, most preferably about 1:0.018.

Antimicrobial compound

The antimicrobial compound is preferably selected from the group of quaternary ammonium material preferably salts, antimicrobial alcohols, antimicrobial phenols, antimicrobial organic acids/salts, or combinations thereof.

Preferred antimicrobial alcohols include, but are not limited to phenoxy ethanol, benzyl alcohol, dichlorobenzyl alcohol, dimethyl oxazolidine, DM DM Hydantoin, 2-bromo-2- nitropropane-l,3-diol, diazolidinyl urea, hexachlorophene.

Preferred antimicrobial phenols include, for instance, triclosan, thymol, dichlorophenol, 2-chloro-4-fluoro phenol, tetrafluorobenzoic acid, cresol, hexylresorcinol, microlides, etc.

Preferred antimicrobial organic acids/salts are selected from benzoic acid/sodium benzoate, salicylic acid/sodium salicylate, sorbic acid/potassium sorbate, sodium hydroxymethyl glycinate, cyclohexane diacetic acid monoamide, chloronicotinic acids, succinic acid, peracetic acid or zinc pyrithione, ketoconazole, piroctone olamine (Octopirox®), or combinations thereof. Preferred quaternary ammonium materials or salts are selected from the group comprising cetylpyridinium chloride (CPC), cetyltrimethylammonium chloride (CTAC), cetyltrimethylammonium bromide (CTAB), benzalkonium chloride (BKC), benzethonium chloride (BZC), cetrimide, polyhexamethylene BH. Further more preferred quaternary ammonium salts are selected from the group comprising CPC, CTAC, CTAB, BKC, or BZC.

In a preferred embodiment, the at least one antimicrobial compound is a quaternary ammonium salt, more preferably the at least one antimicrobial compound is cetylpyridinium chloride (CPC).

The concentration of the antimicrobial compound in the antimicrobial composition will depend on the use of the composition. Accordingly, in some embodiments, the antimicrobial composition will comprise modified clay particles comprising the antimicrobial compound in a therapeutically effective amount. In another embodiments, the antimicrobial composition will comprise modified clay particles comprising the antimicrobial compound in a cosmetically effective amount.

Typically, the composition comprises from 0.01wt.% to 10 wt.% of the modified particle (/.e., the particle comprising the at least one antimicrobial compound), by total weight of the composition, more preferably 0.01 wt.% to 5 wt.%. Preferably, the antimicrobial compound is CPC, thus the particle is a CPC-clay particle.

Polymeric compound

The polymeric compound is one or more copolymers selected from

(i) a copolymer of styrene sulfonic acid and maleic acid; (ii) poly(ethylene succinate);

(iii) poly(ethylene adipate); (iv) phosphino carboxylic acid copolymer; or (v) carboxylate sulfonate terpolymer.

Preferred polymer of the class (i) copolymer of styrene sulfonic acid and maleic acid is poly(4-styrenesulfonic acid-co-maleic acid) sodium salt. This compound or its acid form has the structure as below:

OR

It is available with the CAS number: 68037-40-1.

Polymer of the class (ii) poly(ethylene succinate) has the structure as given below:

Which has the CAS number: 25569-53-3

Polymer of the class (iii) poly(ethylene adipate) has the structure as given below:

Which has the CAS number: 24938-37-2. Polymer of the class (iv) phosphino carboxylic acid copolymer has the structure as given below: Which has the CAS number 110224-99-2.

Preferred polymer of the class (v) carboxylate sulfonate terpolymer is either nonionic or anionic in nature, preferably anionic. An especially preferred polymer of this class is acrylic acid/N-tert-butylacrylamide/2-acrylamido-2methyl-1-propanesulfonic acid copolymer which has the CAS number 7732-18-5.

It is preferred that the polymeric compound is selected from a copolymer of styrene sulfonic acid and maleic acid; a phosphino carboxylic acid copolymer; or a carboxylate sulfonate terpolymer.

Preferably, the polymeric compound is included in an amount of 0.01-10 wt.%, more preferably 0.1-5 wt.% by weight of the composition.

In one preferred embodiment, the composition is an oral care composition. Preferably, the oral care composition is selected from toothpaste, dentifrice, tooth powder, topical oral gel, mouth rinse, denture product, mouth spray, lozenge, oral tablet, chewing gum, impregnated dental implement, dental floss, and combinations thereof. Most preferred product is a toothpaste or mouth rinse.

When formulated for oral care benefits, the composition comprises an orally acceptable base. The orally acceptable base preferably comprises an abrasive, a humectant, a surfactant, a volatile alcohol or combinations thereof. More preferred orally acceptable bases include an abrasive, a humectant or mixtures thereof. The orally acceptable base is included in at least 80% more preferably at least 90%, by weight of the composition.

The oral care composition of the present invention may be delivered in the form of an ointment, a gel, a dentifrice or a mouthwash. Dentifrices include forms like toothpaste and toothpowder. The composition is most preferably presented in the form of a toothpaste, a toothpowder or a mouthwash.

Oral care composition of the present invention preferably comprises an abrasive. Gels usually contain silica, whereas opaque creams generally contain calcium based abrasives, especially chalk. Abrasive silica for incorporation in the composition of the invention is preferably one with a low refractive index. It may be used as the sole abrasive silica, or in conjunction with a low level of other abrasive silicas, e . g . those according to EP236070. The low refractive index silicas , used as abrasives in the present invention are preferably silicas with an apparent refractive index (Rl) in the range of 1.41 to 1.47, preferably 1.435 to 1.445 , preferably having a weight mean particle size of between 5 and 15 mm, a BET (nitrogen) surface area of between 10 and 100 m²/g and an oil absorption of about 70 - 150 cm³/100 g, but abrasive silicas with a lower apparent refractive index may also be used . Typical examples of suitable low refractive index abrasive silicas (e.g. having an Rl of between 1.435 and 1.445) are Tixosil 63 and 73 ex Rhone Poulenc ; Sident 10 ex Degussa; Zeodent 113 ex Zeofinn; Zeodent 124 ex Huber, Sorbosil AC 77 ex Crosfield Chemicals (having an Rl of approximately 1.440). The amount of these silicas in the composition of the present invention generally ranges from 5-60% by weight , usually 5-20% by weight of the composition.

In a preferred embodiment, the composition comprises a thickener. Thickeners that may be used in this invention include, sodium carboxymethyl cellulose (SCMC), hydroxyl ethyl cellulose, methyl cellulose, ethyl cellulose, gum tragacanth, gum arabic, gum karaya, xanthan gum, sodium alginate, carrageenan gum, guar gum, Irish moss, starch, modified starch, silica based thickeners including silica aerogels, magnesium aluminum silicate (e.g., Veegum), Carbomers (cross-linked acrylates) and mixtures thereof.

Typically, thickening silica, sodium carboxymethyl cellulose and/or a Carbomer is/are preferred thickeners for use in the composition of the invention. When a Carbomer is employed, those having a weight-average molecular weight of at least 700,000 are desired, and preferably, those having a molecular weight of at least 1,200,000, and most preferably, those having a molecular weight of at least about 2,500,000 are desired. Mixtures of Carbomers may also be used herein.

In an especially preferred embodiment, the Carbomer is Synthalen PNC, Synthalen KP or a mixture thereof. It has been described as a high molecular weight and cross- linked polyacrylic acid and identified via CAS number 9063-87-0. These types of materials are available commercially from suppliers like Sigma.

In another especially preferred embodiment, the sodium carboxymethyl cellulose (SCMC) used is SCMC 9H. It has been described as a sodium salt of a cellulose derivative with carboxymethyl groups bound to hydroxy groups of glucopyranose backbone monomers and identified via CAS number 9004-32-4. The same is available from suppliers like Alfa Chem.

Thickening silica is especially preferred to be used in gel toothpastes.

Gel toothpastes generally contain upto 8.5 wt% thickening silica whereas opaque toothpastes typically contain 3 to 4 wt% thickening silica.

When present, preferred thickening silicas include AEROSIL T series from Degussa or the CAB-O-SIL series from Cabot Corporation, silica gels such as the SYLODENT or SYLOX series from W. R. Grace & Co or precipitated silica such as ZEOTHIX 265 from J. M. Huber Corporation. Useful silica thickeners also include ZEODENT 165, ZEODENT 163 and/or 167 and ZEOFREE 153, 177, and/or 265 silicas, all available from J. M. Huber Corporation. Other preferred thickening silicas include MFIL, MFIL-P (From Madhu Silica, India), SIDENT 22 S and AEROSIL 200 (Ex. Evonik Industries), SYLODENTand PERKASIL thickening silicas from WR Grace & Company and Tixosil 43 and 331 from Rhodia, synthetic finely divided pyrogenic silica such as those sold under the trademarks SYLOID 244, SYLOID 266 and AEROSIL D- 200.

Thickener, when present, preferably makes up from 0.01 to about 10%, more preferably from 0.1 to 9%, and most preferably, from 1.5 to 8% by weight of the composition.

Suitable humectants are preferably used in the oral care composition of the present invention and they include, for example, glycerin, sorbitol, propylene glycol, dipropylene glycol, diglycerol, triacetin, mineral oil, polyethylene glycol (preferably, PEG-400), alkane diols like butane diol and hexanediol, ethanol, pentylene glycol, or a mixture thereof. Glycerin, polyethylene glycol, sorbitol or mixtures thereof, are the preferred humectants, most preferred ones being glycerol (also known as glycerine) and sorbitol.

The humectant may be present in the range of from 10 to 90% by weight of oral care compositions. More preferably, the humectant makes up from 25 to 80%, and most preferably, from 45 to 70% by weight of the composition, based on total weight of the composition and including all ranges subsumed therein.

Preferably, an oral care composition comprises a surfactant. When formulated as a toothpaste, the composition preferably comprises 0.01 to 20%, by total weight of the composition, of a surfactant. Preferably the composition comprises at least 0.01% surfactant by weight of the composition, more preferably at least 0.1% and most preferably from 0.5 to 7%. Suitable surfactants include anionic surfactants, such as the sodium, magnesium, ammonium or ethanolamine salts of C8 to C18 alkyl sulphates (for example sodium lauryl sulphate), C8 to C18 alkyl sulphosuccinates (for example dioctyl sodium sulphosuccinate), C8 to C18 alkyl sulphoacetates (such as sodium lauryl sulphoacetate), C8 to C18 alkyl sarcosinates (such as sodium lauryl sarcosinate), C8 to C18 alkyl phosphates (which can optionally comprise up to 10 ethylene oxide and/or propylene oxide units) and sulphated monoglycerides. More preferably the surfactant comprises or is an anionic surfactant. The preferred anionic surfactants are sodium lauryl sulphate and/or sodium dodecylbenzene sulfonate. Most preferably the surfactant is sodium lauryl sulphate. Other suitable surfactants include nonionic surfactants, such as optionally polyethoxylated fatty acid sorbitan esters, ethoxylated fatty acids, esters of polyethylene glycol, ethoxylates of fatty acid monoglycerides and diglycerides, and ethylene oxide/propylene oxide block polymers. Other suitable surfactants include amphoteric surfactants, such as betaines or sulphobetaines. Mixtures of any of the above described materials may also be used. Most preferred surfactants are an alkali metal alkyl sulphate or a betaine.

Water may preferably be included in 5 to 95%, in particular 10 to 75%, and especially at from 10 to 60%, further more preferably 10 to 45% by total weight of the composition.

When the oral care composition of this invention is a toothpaste or gel, the same typically has a viscosity from about 30,000 to 180,000 centipoise, and preferably, from 60,000 to 170,000 centipoise, and most preferably, from 65,000 to 165,000 centipoise.

The oral care composition of the present invention may contain a variety of other ingredients which are common in the art to enhance physical properties and performance. These ingredients include antimicrobial, anti-caries agents, plaque buffers, fluoride sources, vitamins, plant extracts, desensitizing agents, anti-calculus agents, biomolecules, flavors, proteinaceous materials, preservatives, opacifying agents, coloring agents, pH-adjusting agents, sweetening agents, particulate abrasive materials, polymeric compounds, buffers and salts to buffer the pH and ionic strength of the compositions, and mixtures thereof. Such ingredients typically and collectively make-up less than 20% by weight of the composition, and preferably, from 0.0 to 15% by weight, and most preferably, from 0.01 to 12% by weight of the composition, including all ranges subsumed therein.

Preferably, the composition comprises one or more orally acceptable component, such as abrasives, orally accepted actives (such as Fluor), teeth whiteners, fragrances, stabilizers, preservatives, among other conventional components to oral care compositions. Uses of the antimicrobial composition

The present inventors have found that the composition according to the invention has an improved antimicrobial activity. Accordingly, the antimicrobial composition can be used for cosmetic (non-therapeutic) or therapeutic applications. a) Therapeutic uses

In one aspect, the composition according to the invention is for use in the prevention or treatment of a disease of a mammal. Diseases as used herein refer to diseases caused by micro-organisms on body surfaces (skin, nails, mucosa, etc.). In one embodiment the diseases are skin diseases such as selected from the group comprising acne, eczema, or bacterial or fungal infections on the scalp, nails or skin, such as those caused by Propionibacteria spp., Corynebacteria spp., Actinobacteriales, Staphylococci spp. (e.g. S. epidermidis), Lactobacilales, Clostridiales, proteobacteria,

Flavobacteriales, Bacteriodales, Malassezia yeasts (e.g. Malassezia furfur and Malassezia 14lobose ), among others.

Preferably, the use is in the prevention or treatment of a disease in the oral cavity. Preferred diseases in the oral cavity are selected from caries, tartar, dental plaque, gum diseases, and combinations thereof, for instance diseases caused by Actinomyces spp, Streptococcus spp (such as S. mutans and S. sobrinus),

Lactobacillus ssp. (such as, Lactobacillus acidophilus), Nocardia spp., Haemophilus spp, Capnocytophaga spp, Veillonella spp, Neisseria, Fusobacterium, such as F. nucleatum, Treponema spp, Tannerella ssp., such as T. forsythensis, P. gingivalis, Aggregatibacter actinomycetemcomitans, and others.

In a further aspect, the antimicrobial composition of the invention is for use in the removal of oral biofilm in a mammal subject. b) Cosmetic/Non-therapeutic uses

The present invention provides cosmetic uses of the antimicrobial composition on body surfaces, such as skin, teeth, scalp, mucosa (gums), tongue, etc. The inventors have found an improved antimicrobial activity on micro-organisms normally found on said body surfaces and which may impair body appearance (such as teeth yellowing) or body odor, in particular mouth malodor. Preferably, the antimicrobial composition is for cosmetic use in the prevention or treatment of halitosis caused by microorganisms in the oral cavity.

Accordingly, in yet another aspect, the invention relates to a non-therapeutic method of treating the skin or oral cavity of a mammal, the method including the step of contacting the skin or oral cavity of a mammal with the antimicrobial composition according to the present invention.

In another aspect, the invention relates to the use of an antimicrobial composition of the invention for reducing body malodor, preferably mouth malodor, and/or for reducing oral biofilm formation and/or for reducing tooth discoloration, in a mammal.

Examples

Example 1: Preparation of modified clay particle

To prepare the modified clay particle comprising an antimicrobial compound according to the invention, the following method was used:

5g of Kaolinite (Super shine 90, EICL) was taken in a 500ml of 0.1 N HCI (Merck) solution and sonicated for 30 minutes. The pH is then increased to 9 by addition of NaOH (Merck) solution drop wise. To this 10g CPC was added and the suspension was stirred over a magnetic stirrer (Spinpot) for 6 hours while maintaining the temperature of the solution at 75-80 °C. The suspension was then washed with water for about 10 times to remove the excess CPC and a final ethanol (Les Alcools De Commerce) wash was given. The clay was then dried in a hot air oven.

To determine that CPC was attached on the clay after reaction FTIR- spectroscopy method was utilized. The instrument used was Perkin Elmer instruments, Spectrum One FT-IR Spectrometer. Powder (diffuse reflectance) technique was utilized for this measurement. Clay as control and reacted clay of the invention were grounded with 50% w/w of KBr in a pestle and mortar and then IR was done on these powders. The IR spectrum of the reacted clay was compared against that of pure clay. New peaks were observed in the reacted clay at the wave numbers of 2926 cm-1 , 2855 cm-1 ,

1487 cm-1 and 1466 cm-1. The peaks at 2926 cm-1 and 2855 cm-1 are due to the C-C stretching of the alkyl chain of the CPC, while the peaks at 1487 cm-1 and 1466 cm-1 are due to the ring carbon and nitrogen of the CPC. Example 2: Antimicrobial activity of the actives

Antimicrobial activity of the compositions according to the invention has been compared with compositions comprising either only the modified clay particle comprising an antimicrobial compound (‘CPC’, prepared as in Ex. 1), or only the copolymer. Salivary flora and actives (according to Table 1 below) were co-incubated overnight and at the end of incubation biofilm was stained with crystal violet. Detailed protocol is as mentioned below:

Treatment and Biofilm formation

Early morning saliva samples before brushing was collected from 4-5 people, pooled together and washed twice in saline. Absorbance was set to 0.2 OD620nm in ultra- filtered tryptone yeast extract broth (2% sucrose) and used for experiments as mentioned in further steps. 2ml of set culture was added into 24 / 12 well plate to which test actives at varying concentrations were added into each of the wells. The plate was incubated anaerobically overnight at 37°C.

Staining protocol

At the end of overnight incubation, the plate was decanted over a biohazard bag to remove all the planktonic bacteria. The plate was then rinsed in a tray of water and the water was then decanted out over the tray. This step was done once to remove the loosely adhered biofilm. The plate was then placed on a blotting paper /paper towel over the bench top. All the test wells were with stained with 1 ml of 1 % Crystal violet stain (CV) for 10 min. This step was done using a pipette. The plate was decanted over the biohazard discard bag to remove all the stain. The plate was then rinsed in a tray of water and the water was poured out over the tray. This step was done thrice consecutively, in three separate trays of water. (Each tray procedure was repeated thrice - total 9 rinses). The bench top was covered with more blotting paper / paper towel and the plate was hit against the bench top until all the wells are free of any liquid. This step was done to ensure that only CV remaining is bound to a biofilm at the bottom of a well. The plate was left face up on the bench top at room temperature (23+2 °C) until it dried completely. 1ml of 33% glacial acetic acid was added to the test wells to solubilize the biofilm bound CV stain. The acetic acid was allowed sit for 10 mins. The mix of acetic acid and CV in the wells was pipetted up and down the well. 10mI of above solution was transferred to 90mI of 33% acetic acid in a well of flat bottom 96 well plate. The solution was mixed well and absorbance was taken at 540 nm. All the test actives were done in duplicate. The % biofilm obtained for each of the samples is summarized in the Table below:

Table 1

¹ PSS-Co maleic acid is a copolymer of styrene sulfonic acid and maleic acid

² CPC Clay is the modified clay particle as prepared in Example 1

³ ConWTP3100 is a carboxylate sulfonate terpolymer The data in Table -1 above indicates that the compositions comprising both modified clay and copolymer (Examples 2D, 2F and 2H) provide synergistic anti biofilm efficacy over the individual components (Examples 2B, 2C, 2E and 2G).

Claims

1. An antimicrobial composition comprising: a) a modified clay particle comprising an antimicrobial compound, the modified clay particle comprising:

(ii) at least one orally acceptable antimicrobial compound attached to the coordinating cation on an external surface plane of the clay particle; and b) a polymeric compound selected from (i) a copolymer of styrene sulfonic acid and maleic acid; (ii) poly(ethylene succinate); (iii) poly(ethylene adipate); (iv) phosphino carboxylic acid copolymer; or (v) carboxylate sulfonate terpolymer;and wherein the antimicrobial compound is a quaternary ammonium material.

2. A composition as claimed in claim 1 wherein the quaternary ammonium material is selected from cetylpyridinium chloride (CPC), cetyltrimethylammonium chloride (CTAC), cetyltrimethylammonium bromide (CTAB), benzalkonium chloride (BKC), benzethonium chloride, cetrimide, and polyhexamethylene BH;.

3. A composition as claimed in claim 1 or 2, wherein the antimicrobial compound is attached to coordinating cations on the external surface of the octahedral surface plane.

4. A composition as claimed in any one of the preceding claims wherein the clay : antimicrobial compound weight ratio is between 1:0.001 to 1:0.1.

5. A composition as claimed in any one of the preceding claims, wherein quaternary ammonium material is cetylpyridinium chloride (CPC).

6. A composition as claimed in any one of the preceding claims, wherein the modified clay particle is in the range of 0.01-10% by weight of the composition.

7. A composition as claimed in any one of the preceding claims, wherein the polymeric compound is selected from (i) a copolymer of styrene sulfonic acid and maleic acid; (ii) phosphino carboxylic acid copolymer; or (iii) carboxylate sulfonate terpolymer.

8. A composition as claimed in any one of the preceding claims, wherein the amount of polymeric compound is in the range of 0.01 to 10% by weight of the composition.

9. A composition as claimed in any one of the preceding claim which is included in an oral care product selected from toothpaste, dentifrice, tooth powder, topical oral gel, mouth rinse, denture product, mouth spray, lozenge, oral tablet, chewing gum, impregnated dental implement, dental floss, and combinations thereof.

10. A composition as claimed in any one of the preceding claims for use in the prevention or treatment of a disease of a mammal, preferably for use in the prevention or treatment of a disease in the oral cavity selected from the group comprising caries, tartar, dental plaque, gum diseases, and combinations thereof.

11. A composition as claimed in any one of the preceding claims 1 to 9 for use in the removal of oral biofilm in a mammal subject.

12. A non-therapeutic method of treating the skin and/or oral cavity of a mammal, the method including the step of contacting the skin and/or oral cavity of a mammal with the antimicrobial composition as claimed in any one of the preceding claims 1 to 9.

13. Use of a composition as claimed in any one of claims 1 to 9, for reducing body malodor, preferably mouth malodor, and/or for reducing oral biofilm formation and/or for reducing tooth discoloration, in a mammal.