Antimicrobial composition

Abstract

The present invention relates to an antimicrobial composition, more particularly a liquid composition, which is not caustic on cleaned and disinfected surfaces, such as fabrics and dishware, particularly those washed with hands, and which is also used for the hygiene treatment of hands and other body surfaces. The invention can also be used to develop products for use as multi-purpose sanitary liquid compositions useful for cleaning / disinfecting any one or more of the aforementioned surfaces. This is achieved by combining an amino acid-based surfactant having a specific pKa value with a C3-C9 alkane diol, while the composition has a pH in the range of 2.5 to 4.5.

Description

Field of the Invention

[0001] The present invention relates to an antimicrobial composition, more particularly to a liquid composition which is not caustic on surfaces being cleaned and disinfected (such as fabrics or dishes, especially those washed by hand), and is also used for sanitizing hands and other body surfaces. The present invention can also be used to develop products that can be used as multi-purpose sanitary liquid compositions that can be used to clean / disinfect any one or more of the above surfaces. Background of the Invention

[0003] Disinfectant cleaning compositions are very beneficial to individuals because proper use can generally reduce the number of germs and pathogens that individuals are exposed to. Such compositions can, for example, play an important role in reducing the occurrence and spread of infectious diseases. Disinfectant compositions containing chlorine-based bleaches are known. These compositions are sometimes considered to be quite harsh because when they come into contact with the skin or mucous membranes of an individual, they may exhibit undesirable side effects such as corrosion, odor (such as the smell of chlorine) and skin irritation or skin sensitization. In addition, it is known that surfactants such as soaps and other relatively harsh surfactants in combination with other compounds such as organic acids provide relatively good antimicrobial activity. However, there are specific situations in which such cleaning and disinfection are achieved when the composition is applied to a substrate by hand or in the case where the substrate is the hand itself. In such cases, consumers expect the disinfectant composition to be gentle on the hands, but still provide a high level of antimicrobial activity. Such substrates include tableware, clothing and other fabrics that are particularly washed by hand.

[0004] The inventors unexpectedly discovered during the development of various antimicrobial compositions that a combination of an amino acid-based surfactant and a specific alkane diol having a specific pKa value in a narrow pH range of 2.5 to 4.5 can achieve high antimicrobial activity. This is indeed surprising, as neither of these two ingredients is known to have any significant antimicrobial activity by itself. To the best of the inventors' knowledge, such a combination of active substances has not been combined and used to provide high antimicrobial activity under the claimed conditions.

[0005] It is therefore an object of the present invention to provide antimicrobial compositions that are mild on the skin. Summary of the invention

[0006] According to a first aspect of the present invention, there is provided an antimicrobial composition comprising

[0007] (i) 0.01 to 2 wt % of an amino acid based surfactant having a pKa value in the range of 3 to 5;

[0008] (ii) 0.05 to 2 wt. % of a C3-C9 alkane diol;

[0009] wherein the composition has a pH in the range of 2.5 to 4.5. DETAILED DESCRIPTION OF THE INVENTION

[0011] For the avoidance of doubt, any feature of one aspect of the present invention may be used for any other aspect of the present invention. The word "comprising" is intended to mean "including", but not necessarily "consisting of" or "consisting of". Therefore, the term "comprising" is not meant to be limited to any subsequently stated elements, but optionally also includes non-specific elements with primary or secondary functional importance. In other words, the steps or options listed do not have to be exhaustive. Whenever the words "comprising" or "having" are used, these terms mean to be equivalent to "comprising" defined above. It should be noted that the examples given in the following description are intended to illustrate the present invention, but are not intended to limit the present invention to these examples themselves. Except in the embodiments, or where otherwise clearly indicated, all numbers representing the amount or reaction conditions of the material, the physical properties of the material and / or the use in this specification should be understood to be modified by the word "about". Unless otherwise stated, the numerical range expressed in the "x to y" format should be understood to include x and y. When multiple preferred ranges are described in the "x to y" format for a particular feature, it should be understood that all ranges combining different endpoints are also considered. Unless otherwise indicated, amounts used herein are expressed as weight percent based on the total weight of the composition, abbreviated as "wt %".

[0012] Throughout this specification, the term "disinfection" refers to the reduction of the number of viable microorganisms in a given medium or on a given surface. Typically, disinfection involves the destruction or inactivation of microorganisms. Living and inanimate media and surfaces are contemplated.

[0013] The term "antimicrobial agent" refers to a compound capable of killing, inhibiting or controlling the growth of microorganisms at a locus; antimicrobials include bactericides, fungicides and algaecides, although the present invention is more useful against bacteria.

[0014] The compositions of the present invention are preferably used for non-therapeutic uses and are more particularly preferably used for cleaning surfaces such as those on dishes, clothing and other fabrics and body surfaces such as the hands.

[0015] The composition comprises an amino acid-based surfactant having a pKa value in the range of 3-5. They are preferably selected from one or more of sodium lauroyl sarcosinate, sodium oleoyl sarcosinate, sodium oleoyl glutamate, sodium oleoyl glycinate, disodium cocoyl glutamate, sodium cocoyl glutamate, disodium lauroyl glutamate, sodium cocoyl glycinate and sodium lauroyl glycinate. Among them, sarcosinate surfactants are more preferred than glutamate surfactants, and glutamate surfactants are more preferred than glycinate surfactants. Therefore, the most preferred amino acid surfactant for the present invention is selected from one or both of sodium lauroyl sarcosinate and sodium oleoyl sarcosinate.

[0016] The amino acid surfactant is included at 0.01 to 2%, preferably 0.02 to 1% by weight of the composition.

[0017] The composition of the present invention comprises C3-C9 alkane diol. Preferably, the alkane diol is selected from one or more of propylene glycol, hexylene glycol and octanediol. The alkane diol is contained in an amount of 0.05 to 2%, preferably 0.05 to 1%, by weight of the composition.

[0018] Without wishing to be bound by theory, the inventors believe that the selected alkane diols were found to be good membrane permeants which ensured that the amino acid surfactant could then more easily enter the bacterial cells to destroy them, thereby enhancing the antibacterial properties.

[0019] The composition is effective at a pH in the range of 2.5 to 4.5, preferably in the range of 2.5 to 3.5.

[0020] The composition preferably comprises an organic acid. Preferred organic acids for use in the present invention are one or more of lactic acid, glycolic acid, tartaric acid and citric acid. The most preferred acid is citric acid. The organic acid may also be present in the form of a salt. Alkali metal or alkaline earth metal salts are preferred, more preferably alkali metal salts, of which sodium salts are most preferred. The composition comprises 0.1 to 5 wt %, preferably 0.5 to 3 wt %, further more preferably 1 to 2.5 wt % of an organic acid or a salt thereof.

[0021] The composition is usually in liquid form. It contains a large amount of water. Water is usually present in 80-97%, preferably 90-94% by weight of the composition.

[0022] Liquid laundry detergent compositions

[0023] The composition may be provided as a laundry detergent composition which, in addition to the essential ingredients of the present invention, may contain a surfactant.

[0024] The laundry detergent composition in which the present invention can be implemented is preferably in liquid form. The term "liquid" may include emulsions, suspensions and compositions with a flowable but harder consistency, referred to as gels or pastes. Pourable liquid detergent compositions preferably have a viscosity of 200 to 1,500 mPa.s, preferably 200 to 700 mPa.s. Such compositions typically have an aqueous continuous phase. Preferably, the composition comprises at least 50% by weight of water, more preferably at least 70% by weight of water. Water is typically present in an amount of 20% to 99.9%, preferably 40% to 80%, of the weight of the composition.

[0025] Liquid laundry detergent compositions typically contain 1 to 30% by weight, preferably 2 to 15% by weight, of one or more surfactants. Surfactants are typically anionic in nature. Amino acid-based surfactants, which are an essential feature of the composition of the present invention, are also anionic surfactants. However, it should be understood that throughout the specification, the use of the term "anionic surfactant" is intended to represent anionic surfactants other than amino acid-based surfactants. Preferred anionic surfactants are organic sulfates and sulfonates having an alkyl group containing about 8 to about 22 carbon atoms, the term "alkyl" being used to include the alkyl portion of a higher acyl group. Examples of such materials include alkyl sulfates, alkyl ether sulfates, alkyl aryl sulfonates, alpha-olefin sulfonates, and mixtures thereof. The alkyl group preferably contains 10-18 carbon atoms and may be unsaturated. The alkyl ether sulfate may contain 1-10 ethylene oxide or propylene oxide units per molecule, preferably 1-3 ethylene oxide units per molecule. The counterions of anionic surfactants are usually alkali metals such as sodium or potassium; or ammonia counterions such as monoethanolamine (MEA), diethanolamine (DEA) or triethanolamine (TEA). Mixtures of these counterions can also be used. Preferred are sodium and potassium.

[0026] The most preferred surfactants are of the alkylbenzene sulfonate type, particularly linear alkylbenzene sulfonates (LAS) having an alkyl chain length of 10-18 carbon atoms. Some alkyl sulfate surfactants (PAS) may be used, such as non-ethoxylated primary and secondary alkyl sulfates having an alkyl chain length of 10-18.

[0027] Preferably, the composition comprises 5 to 20 wt% of a nonionic surfactant based on the total weight of the composition. A preferred class of nonionic surfactants for use in the present invention includes aliphatic C8-C 18 , more preferably C 12 -C 15 Straight chain primary alcohol ethoxylates having an average of 3 to 20, more preferably 5 to 10, moles of ethylene oxide per mole of alcohol. The preferred nonionic surfactant is a C16 / 18 alcohol ethoxylate.

[0028] In addition to the above ingredients, liquid laundry detergent compositions typically contain agents such as soil release polymers, hydrotropes, co-surfactants, builders, polymeric thickeners and opacifying dyes.Soil release polymers (SRPs) help improve the release of soils from fabrics by modifying the fabric surface during washing.

[0029] The SRP structure may also include end-capping groups to control molecular weight or to modify polymer properties such as surface activity. Preferred SRPs for use in the present invention include copolyesters formed by condensation of terephthalate and a diol, preferably 1,2-propylene glycol, and also include end-capped copolyesters formed by repeating units of alkyl-terminated alkylene oxides. When included, the SRP may range from 0.1-10%, ideally 0.3-7%, and more preferably 0.5-5% by weight of the composition.

[0030] The compositions of the present invention may be blended with non-aqueous carriers such as hydrotropes, cosolvents and phase stabilizers. Such materials are typically low molecular weight, water-soluble or water-miscible organic liquids such as C1-C5 monohydric alcohols (e.g., ethanol and n-propanol or isopropanol); C2-C6 diols (e.g., monopropylene glycol and dipropylene glycol); C3-C9 triols (e.g., glycerol); weight average molecular weight (M w ) ranges from about 200 to 600; C1-C3 alkanolamines such as monoethanolamine, diethanolamine and triethanolamine; and alkylaryl sulfonates having up to 3 carbon atoms in the lower alkyl group (e.g., sodium and potassium xylene, toluene, ethylbenzene and cumene (cumene) sulfonates). When included, the non-aqueous carrier may be present in an amount ranging from 0.1-3%, preferably 0.5-1%, by weight of the composition. Preferred hydrotropes are monopropylene glycol and glycerol.

[0031] In addition to the above-mentioned non-soap anionic and / or nonionic detersive surfactants, the liquid laundry detergent compositions of the present invention may contain one or more co-surfactants (such as amphoteric (zwitterionic) and / or cationic surfactants). When included, such co-surfactants may be present in an amount ranging from 0.1 to 5% by weight of the composition.

[0032] Liquid laundry detergent compositions may also optionally contain relatively low levels of organic detergent builders or chelating agents. Examples include alkali metal citrates, succinates, malonates, carboxymethyl succinates, carboxylates, polycarboxylates, aminocarboxylates and polyacetyl carboxylates. If used, organic builder materials may comprise from about 0.5% to 20% by weight of the composition, preferably from 1% to 10% by weight.

[0033] When the composition is a liquid laundry detergent composition it may be diluted with water in a ratio in the range 1 :5 to 1 :300 (eg such as a ratio of 1 :50 or 1 :100, 1 :200) to form a wash liquor.

[0034] Liquid dishwashing compositions

[0035] The composition of the present invention can be used for the maintenance of kitchen items, for example, utensils and tableware that can be cleaned using a liquid dishwashing composition. Various ingredients other than the essential ingredients claimed in the present invention are summarized as follows. Among the various ingredients, anionic surfactants, nonionic surfactants and hydrotropes as detailed in the liquid laundry detergent composition can be used in the liquid dishwashing composition. In addition, other ingredients that may be included are detailed as follows:

[0036] Preferably, the composition also comprises an amphoteric surfactant. Preferably, the amphoteric surfactant is selected from alkylamine oxides, alkyl betaines, alkyl amidopropyl betaines, alkyl sultaines (sultaines), alkyl glycinates, alkyl carboxyglycinates, alkyl amphoacetates, alkyl amphopropionates, alkyl amphoglycolates, alkyl amidopropyl hydroxysultaines, acyl taurates and acyl glutamates, having an alkyl group containing about 8 to about 22 carbon atoms, the term "alkyl" being used to include the alkyl portion of a higher acyl group. More preferably, the amphoteric surfactant is selected from alkyl amidopropyl betaines, even more preferably cocoamidopropyl betaines. When included, the amphoteric surfactant may be present in an amount preferably in the range of 0.1-5 wt %, more preferably 0.1-4 wt %, even more preferably 1-3 wt %. A mixture of any of the above materials may also be used. A good combination of surfactants for use in the present invention in the form of a dishwashing composition is a combination of an anionic surfactant of 1-30 wt % and an amphoteric surfactant of 0.1-5 wt %.

[0037] The liquid dishwashing composition may preferably comprise an organic acid or salt thereof as disclosed above. Preferred is citric acid or a salt thereof, for example trisodium citrate.

[0038] Preferably, the liquid dishwashing composition further comprises water in an amount of 5 to 99 wt.-%, more preferably 10 to 90 wt.-%, even more preferably 15 to 80 wt.-%, further more preferably 20 to 70 wt.-%, still more preferably 30 to 65 wt.-%, still more preferably 35 to 60 wt.-%, yet further more preferably 40 to 55 wt.-%.

[0039] Preferably, the liquid dishwashing composition further comprises one or more chelating agents.Preferably, the composition comprises a chelating agent, which may be present in an amount of 0.1-5 wt%, more preferably 0.25-4 wt%, even more preferably 0.5-2.5 wt%.

[0040] Preferred chelating agents are phosphonic acid or its salt. Phosphonic acid (or its salt) chelating agents are preferably selected from 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP; available as Dequest(R)2010), diethylenetriaminepenta(methylenephosphonic acid) (DTPMP; available as Dequest(R)2066), hexamethylenediaminetetra(methylenephosphonic acid) (HDTMP), aminotri(methylenephosphonic acid) (ATMP), ethylenediaminetetra(methylenephosphonic acid) (EDTMP), tetramethylenediaminetetra(methylenephosphonic acid) (TDTMP); and phosphonobutanetricarboxylic acid (PBTC). The most preferred chelating agent is 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP). It is preferred that the chelating agent is added to the formulation in the form of an acid.

[0041] Optionally, the liquid dishwashing composition further comprises an enzyme with or without a suitable enzyme stabilizer. Preferably, the composition further comprises an effective amount of at least one enzyme with or without a suitable enzyme stabilizer. Examples of suitable enzymes include pectate lyases, proteases, amylases, cellulases, lipases, mannanases; with or without a suitable stabilizer.

[0042] Preferably, the viscosity of the composition is -1 The shear rate of 1000 mPa.s to 1500 mPa.s may suitably be in the range of about 200 mPa.s to about 10,000 mPa.s. This shear rate is the shear rate normally applied to the liquid when pouring from a bottle. Pourable liquid home care compositions typically have a viscosity of 200 to 1,500 mPa.s, preferably 100 to 800 mPa.s.

[0043] The liquid dishwashing composition may further comprise one or more polymers. Preferably, the polymer may be a cationic, anionic, amphoteric or nonionic type having a molecular weight greater than 100,000 daltons. They are known to increase the viscosity and stability of the liquid composition to enhance the sensory feel of the skin during and after use, and to enhance the creaminess and foam stability of the foam. Examples of polymers include polyvinyl alcohol, polyacrylic acid, silanes, siloxanes and mixtures thereof. If present, the polymer may be present in the composition in an amount of preferably 0.001-10 wt %, more preferably 0.1-6 wt %, and still further more preferably 1-3 wt %.

[0044] Preferably, the composition can be used as is, i.e. in neat form, or can be diluted before use. The degree of dilution generally depends on market choice. In some markets, more concentrated products are desired, while in other markets more diluted products are preferred. When the composition is a liquid dishwashing composition, it is generally diluted with water in a weight ratio ranging from 1:1 to 1:10.

[0045] Liquid dishwashing compositions may optionally contain ingredients such as fragrances, colorants, foam boosters and odor absorbing materials.

[0046] Multi-purpose liquid spray composition

[0047] The compositions of the present invention can be used as multi-purpose liquid spray compositions comprising a nonionic surfactant and 50-90% water. This is typically dispensed from a bottle using a spray pump. These types of multi-purpose liquid spray compositions can be used to clean and disinfect inanimate surfaces or animate surfaces. Inanimate surfaces include hard surfaces, such as floors, walls, windows, doors, furniture, and tabletops in various indoor and outdoor locations. Other types of hard surfaces cleaned by such compositions include products found in homes, offices, and other public places. These products can also be used to disinfect topical surfaces of the human or animal body. They can be used as bathing water, as water for shaving, for washing babies between diaper changes, for disinfecting pets and disinfecting hands in homes, hospitals, and medical clinics; and many other personal disinfection applications.

[0048] The multi-purpose liquid spray composition may include a stability enhancer as a nonionic surfactant. The nonionic surfactant used in the present invention is preferably selected from the group comprising fatty alcohol ethoxylates, fatty acid ethoxylates, alkylphenol ethoxylates or polyoxyethylene sorbitan alkyl esters. The nonionic surfactant is preferably included in the multi-purpose liquid spray composition of the present invention in an amount of 0.01-10%, preferably 0.1-5% by weight of the composition.

[0049] The composition of the present invention can be provided as a disinfectant composition comprising 20-50% C2-C3 alcohol and 45-75% water. When above 60% by weight in the composition, alcohol together with water is one of the most effective antimicrobial compositions. They kill bacteria and viruses almost immediately. However, such compositions with high alcohol content are harsh on the skin because it dries out the moisture present on the surface and to some extent below the surface of the skin. Therefore, many people prefer hand disinfectants with low alcohol content. However, 20-50% by weight of alcohol in the composition does not provide complete antimicrobial protection. In these cases, the present invention comprising amino acid surfactants and alkane diols can supplement the antimicrobial activity of alcohol to provide complete protection. Such hand disinfectants can be packaged in small bottles for disinfecting hands when people travel and do not have the opportunity to use soap and water to clean their hands. Such disinfectants can also be placed at the entrances of buildings such as apartments, homes, offices, restaurants and public places such as airports, trains and bus stations. They are particularly useful in hospitals and clinics to minimize the spread of germs through hand contact.

[0050] Suitable alcohols for inclusion in the disinfectant composition of the present invention are ethanol, propanol, isopropanol and combinations thereof. Ethanol is the most preferred alcohol. The composition preferably comprises a combination of ethanol and isopropanol. When ethanol is present, it is preferably included in 25-45% by weight of the composition. When isopropanol is present, it is preferably included in 1-10% by weight, preferably 1-5% by weight of the composition.

[0051] The disinfectant composition may optionally contain a nonionic surfactant. The nonionic surfactants described above for use in the multi-purpose liquid spray composition may be used in the disinfectant composition.

[0052] The disinfectant composition may optionally contain 0.01-1 wt %, preferably 0.05-0.8 wt %, more preferably 0.05-0.5 wt % of a thickener.

[0053] The thickener in the disinfectant composition according to the present invention is preferably selected from homopolymers, copolymers and combinations thereof, wherein the homopolymers and copolymers contain monomers selected from acrylic acid, acrylates, compounds containing acrylate groups and combinations thereof. The most preferred thickeners for the disinfectant composition are those of carbomer compounds. In a preferred embodiment, the disinfectant composition may contain 0-15% by weight of optional ingredients, such as chelating agents, colorants, spices, skin conditioners, vitamins such as vitamin B3 and combinations thereof. The disinfectant composition preferably contains skin conditioners, and these skin conditioners are preferably selected from silicones, siloxanes and combinations thereof. The composition preferably contains vitamins other than vitamin B3, and these vitamins are preferably selected from vitamin A, vitamin E or combinations thereof. Even more preferably, the composition contains vitamin E acetate.

[0054] The invention will now be illustrated by the following non-limiting examples. Example

[0055] Examples AJ, 1-6: Effect of compositions outside the present invention on antibacterial efficacy compared to compositions within the present invention ring:

[0056] The following compositions shown in the following Table-1 were prepared.

[0057] Table-1:

[0058]

[0059] The antibacterial efficacy of the above compositions against Staphylococcus aureus (S. aureus) and Enterococcus hirae (E. hirae) was tested using the procedure given below.

[0060] European standard EN 1276 (Quantitative suspension test for the evaluation of the bactericidal activity of chemical disinfectants and preservatives used in food, industrial, domestic and institutional areas) is used to measure the log kill.

[0061] Data on bacterial efficacy in terms of log kill at 5 minutes contact time with various compositions are given in Table 2 below:

[0062] Table-2

[0063] Example Staphylococcus aureus, log kill Enterococcus hirae, log kill A 2.1 1.3 B 0.2 0.5 1 5.0 5.0 C 0.5 0.3 2 >5 >5 D 3.1 3.0 E 0.3 0.4 3 >5 >5 F 4.6 3.5 G 1.8 1.8 4 >5 >5 H 0.5 0.1 I 0.1 0.5 5 1.5 0.6 J 0.7 - 6 3.1 -

[0064] In the above table, >5 log kill means from 10 7 Starting with 100 bacteria, "no growth" of bacteria was observed after 5 minutes of treatment with the composition (indicating almost complete killing of the bacteria).

[0065] The data in Table 2 above demonstrate that the compositions according to the present invention (Examples 1 to 6) provide synergistic antimicrobial kill within a contact time of 5 minutes compared to the kill provided by the individual components (Examples A to J).

Claims

1. An antimicrobial composition comprising (i) 0.01 to 2 wt % of an amino acid based surfactant having a pKa value in the range of 3 to 5; (ii) 0.05 to 2 wt. % of a C3-C9 alkane diol; wherein the composition has a pH in the range of 2.5 to 4.

5.

2. The composition of claim 1, wherein the amino acid surfactant is selected from one or more of sodium lauroyl sarcosinate, sodium oleoyl sarcosinate, sodium oleoyl glutamate, sodium oleoyl glycinate, disodium cocoyl glutamate, sodium cocoyl glutamate, disodium lauroyl glutamate, sodium cocoyl glycinate and sodium lauroyl glycinate.

3. The composition of claim 1 or 2, wherein the alkane diol is selected from one or more of propylene glycol, hexylene glycol or octanediol.

4. A composition as claimed in any preceding claim comprising 0.02-1 wt% of an amino acid based surfactant.

5. A composition as claimed in any preceding claim comprising an organic acid.

6. The composition of claim 5, wherein the organic acid is selected from one or more of lactic acid, glycolic acid, tartaric acid and citric acid; preferably citric acid.

7. A composition as claimed in claim 5 or 6, wherein the organic acid comprises 0.1 to 5% by weight of the composition.

8. A composition as claimed in any one of the preceding claims 1 to 7 which is a liquid laundry detergent composition additionally comprising from 1 to 30 wt% of anionic surfactant.

9. A composition as claimed in any one of the preceding claims 1 to 7 which is a liquid dishwashing composition additionally comprising from 1 to 30 wt% of anionic surfactant and from 0.1 to 5 wt% of amphoteric surfactant.

10. A composition as claimed in any one of the preceding claims 1 to 7 which is a multi-purpose liquid spray composition comprising a nonionic surfactant and 50 to 90% water.

11. A composition as claimed in any one of the preceding claims 1 to 7 which is a disinfectant composition further comprising 20 to 50% of a C2-C3 alcohol and 45 to 75% of water.

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