Antimicrobial compositions comprising fatty acid antimicrobial boosters, stabilized compositions thereof, and applications thereof in product formulations

Abstract

The present disclosure provides for the use of saturated straight-chain fatty acids having a carbon chain length of from 6 to 12 carbons and / or salts thereof to unexpectedly boost the antimicrobial activity of phenoxyethanol, benzyl alcohol or a combination thereof in product formulations having pH values of 6.0 and higher. The present disclosure further relates to stabilized antimicrobial compositions containing phenoxyethanol, benzyl alcohol or a combination thereof, at least one saturated straight-chain fatty acid having a carbon chain length of from 6 to 12 carbons and / or a salt thereof and an alkaline stabilizer.

Description

[0001] TITLE

[0002] Antimicrobial Compositions Comprising Fatty Acid Antimicrobial Boosters, Stabilized Compositions Thereof, and Applications Thereof in Product Formulations

[0003] FIELD OF INVENTION

[0004] The present invention relates to the use of certain fatty acids and / or salts thereof to unexpectedly boost the antimicrobial activity of certain antimicrobial agents in product formulations having a pH of at least 6.0 and further relates to stabilized antimicrobial compositions containing the antimicrobial agent(s) and the fatty acid(s) and / or salt(s) thereof.

[0005] BACKGROUND OF THE INVENTION

[0006] Preservation against microbial contamination of product formulations, such as personal care products (e.g., cosmetic products) and home care products, plays a pivotal role in consumer safety, product stability, integrity, and quality assurance, regulatory compliance, sustainability, among other factors. Traditional preservatives, such as isothiazolinones, formaldehyde releasers, parabens, and IPBC, are under increasing scrutiny concerning potential health and environmental impacts. This, along with consumer preferences, have led to a growing demand for alternative preservation agents that are both effective and aligned with contemporary expectations. While many product formulators have turned to “soft” preservatives, such as phenoxyethanol and benzyl alcohol, such agents alone often do not provide full spectrum antimicrobial efficacy necessary for robust protection, particularly at around neutral or higher pH levels, potentially complicating their use in product formulations and / or requiring undesirably high dosing levels of such agents.

[0007] Accordingly, there is a pressing need to address the efficacy gap of certain soft preservatives, particularly at around neutral or higher pH levels, while aligning with increasing consumer demand for natural and sustainable products.

[0008] Various fatty acid compounds are known to exhibit certain levels of antimicrobial activity relative to the pH of the end-use formulation. It is generally understood that to practically benefit from such antimicrobial activity the fatty acid compounds should be used in formulations having an acidic pH, in particular taking into account the pKa values of the acids.

[0009] For example, US 2022 / 0395481 Al discloses a bacteriostatic composition containing, among other ingredients, one or more fatty acids and / or salts thereof preferably selected from the group consisting of propionic acid, butyric acid, hexanoic acid, caprylic acid, capric acid, undecylic acid and salts thereof and wherein the pH value of the composition ranges from 3.1 to 4.8, most preferably in the range of 3.8 to 4.4.

[0010] US 11,607,377 B2 discloses a non-soap liquid cleanser composition comprising caprylic acid, wherein the composition has a pH value from 4.5 to 5.5, most preferably from 4.5 to 4.9. US 10,406,135 B2 discloses preservative compositions containing isosorbide monoester and alcohols that contain at least one aromatic group. The reference discloses that its described compositions can beneficially be used at higher pH values but that organic acids frequently only have good activity in the pH range from 3.5 to 6 and describes caprylic acid as having no antimicrobial activity at a pH of 6 or above.

[0011] In accordance with the present disclosure, it was discovered that saturated straight-chain fatty acids having a carbon chain length of from six to twelve carbon atoms and / or salts thereof surprisingly boost the antimicrobial activity of phenoxyethanol (2-phenoxyethan-l-ol), benzyl alcohol or a combination thereof in product formulations having a pH of at least 6.0 (which is above the pKa levels of the acids). The presently disclosed combination is therefore advantageously useful in an expansive scope of product formulations around neutral or higher pH levels, while avoiding undesirably high dosing levels of the antimicrobial agent(s).

[0012] It was further discovered in accordance with the present disclosure that an additional antimicrobial agent, such as an alkylhydroxamic acid, can be used — typically in a minority amount relative to the combined amount of (a) an antimicrobial agent selected from phenoxyethanol, benzyl alcohol and combinations thereof and (b) at least one saturated straight-chain fatty acid having a carbon chain length of from six to twelve carbon atoms and / or a salt thereof — to increase the antimicrobial performance of the combination at the same total load level.

[0013] In addition, it was further found in accordance with the present disclosure that the stability over time of an antimicrobial composition comprising phenoxyethanol, benzyl alcohol or a combination and at least one saturated straight-chain fatty acid having a carbon chain length of from six to twelve carbon atoms and / or a salt thereof can be significantly enhanced via the inclusion of at least one alkaline stabilizer.

[0014] SUMMARY OF INVENTION

[0015] The present disclosure provides a stabilized antimicrobial composition comprising (a) an antimicrobial agent selected from the group consisting of phenoxyethanol, benzyl alcohol, and combinations thereof, (b) at least one saturated straight-chain fatty acid having a carbon chain length of from six to twelve carbon atoms and / or a salt thereof, and (c) at least one alkaline stabilizer, wherein the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid (b) are present in a combined amount of from about 50 wt% to about 99.8 wt%, based on the total weight of the composition, further wherein the antimicrobial composition has a pH of from about 5.0 to about 7.5, and wherein the ratio by weight of the antimicrobial agent (a) to the at least one saturated straight-chain fatty acid and / or salt thereof (b) is from about 40: 1 to about 1:5, preferably from about 40: 1 or from about 20: 1 to about 1:2.5. Also provided is an aqueous product formulation, such as a personal care or home care product formulation, comprising an antimicrobial effective amount of an antimicrobial composition of the present disclosure, wherein the product formulation preferably has a pH of at least 6.0, more preferably having a pH higher than 6.0, such as a pH of at least 6.1, at least 6.3, more preferably at least 6.5, at least 6.7, at least 6.9, at least 7.0, at least 7.1, at least 7.2, at least 7.3, at least 7.4, or at least 7.5.

[0016] Further provided is a personal care or home care product formulation comprising an antimicrobial effective amount of a combination of an antimicrobial agent selected from the group consisting of phenoxyethanol, benzyl alcohol and combinations thereof, at least one saturated straight-chain fatty acid having a carbon chain length of from six to twelve carbon atoms and / or a salt thereof, wherein the ratio by weight of the antimicrobial agent to the at least one saturated straight-chain fatty acid and / or salt thereof is from about 40: 1 to about 1:5, preferably from about 40: 1 or from about 20: 1 to about 1:2.5, and wherein the personal care or home care product formulation has a pH of at least 6.0, preferably having a pH higher than 6.0, such as a pH of at least 6.1, at least 6.3, more preferably at least 6.5, at least 6.7, at least 6.9, at least 7.0, at least 7.1, at least 7.2, at least 7.3, at least 7.4, or at least 7.5.

[0017] Also provided is a method of preserving or inhibiting the growth of microorganisms in a personal care or home care product formulation comprising adding to the product formulation an antimicrobial agent selected from the group consisting of phenoxyethanol, benzyl alcohol and combinations thereof, and at least one saturated straight-chain fatty acid having a carbon chain length of from six to twelve carbon atoms and / or a salt thereof, wherein the antimicrobial agent and the at least one saturated straight-chain fatty acid and / or salt thereof are present in the personal care or home care product formulation in a combined antimicrobial effective amount, the ratio by weight of the antimicrobial agent to the at least one saturated straight-chain fatty acid and / or salt thereof is from about 40: 1 to about 1:5, preferably from about 40: 1 or from about 20: 1 to about 1:2.5, and the personal care or home care product formulation has a pH of at least 6.0, preferably having a pH higher than 6.0, such as a pH of at least 6.1, at least 6.3, more preferably at least 6.5, at least 6.7, at least 6.9, at least 7.0, at least 7.1, at least 7.2, at least 7.3, at least 7.4, or at least 7.5.

[0018] Also provided is the use of at least one saturated straight-chain fatty acid having a carbon chain length of from six to twelve carbon atoms and / or a salt thereof to enhance the antimicrobial efficacy of an antimicrobial agent selected from the group consisting of phenoxyethanol, benzyl alcohol and combinations thereof in a personal care or home care product formulation having a pH of at least 6.0, preferably having a pH higher than 6.0, such as a pH of at least 6.1, at least 6.3, more preferably at least 6.5, at least 6.7, at least 6.9, at least 7.0, at least 7.1, at least 7.2, at least 7.3, at least 7.4, or at least 7.5.

[0019] DETAILED DESCRIPTION

[0020] Unless otherwise specified, the following terms are defined as follows:

[0021] As used herein, “formulation” refers to a preparation that is to be preserved or provided with antimicrobial activity by employing the combination of the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) of the present disclosure.

[0022] As used herein, an “antimicrobial effective amount” means an amount to provide a desired antimicrobial effect or activity, such as a desired preservative, antibacterial and / or antifungal effect.

[0023] As used herein, “microorganism” includes, for example, bacteria and fungi (such as yeast and mold). pH values or ranges as provided herein refer to pH at room temperature (20-25 °C), unless otherwise specified.

[0024] In one aspect of the present disclosure, a stabilized antimicrobial composition comprises (a) an antimicrobial agent selected from the group consisting of phenoxyethanol, benzyl alcohol, and combinations thereof, (b) at least one saturated straight-chain fatty acid having a carbon chain length of from six to twelve carbon atoms and / or a salt thereof, and (c) at least one alkaline stabilizer, wherein the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid (b) are present in a combined amount of from about 50 wt% to about 99.8 wt%, based on the total weight of the composition, further wherein the antimicrobial composition has a pH of from about 5.0 to about 7.5, and wherein the ratio by weight of the antimicrobial agent (a) to the at least one saturated straight-chain fatty acid and / or salt thereof (b) is from about 40: 1 to about 1:5, preferably from about 40: 1 or from about 20: 1 to about 1:2.5.

[0025] Saturated straight-chain fatty acids having a carbon chain length of from six to twelve carbon atoms are known to occur naturally and can be derived from plant oils, among other extraction or production processes. Preferably, the at least one saturated straight-chain fatty acid (and / or salt thereof) of the present disclosure has a carbon chain length of from six to ten carbon atoms. The fatty acid (and / or salt thereof) of the present disclosure can be essentially a single saturated straight-chain fatty acid (and / or salt thereof) having a carbon chain length of from six to twelve, preferably from six to ten, carbon atoms or can be any mixture of saturated straight-chain fatty acids (and / or salts thereof) having carbon chain lengths within the range of from six to twelve, preferably from six to ten, carbon atoms . Examples of suitable salts of the fatty acids include, but are not limited to, alkali salts, such as sodium and potassium, and ammonium salts.

[0026] In many embodiments, the antimicrobial agent (a) is phenoxyethanol. In many other embodiments, the antimicrobial agent (a) is benzyl alcohol. In further embodiments, the antimicrobial agent (a) is any combination of phenoxyethanol and benzyl alcohol.

[0027] Preferably, the ratio by weight of the antimicrobial agent (a) to the at least one saturated straight-chain fatty acid and / or salt thereof (b) is from about 40: 1 or from about 20: 1 to about 1:2.5, such as from about 20: 1, preferably from about 15: 1, more preferably from about 10: 1, even more preferably from about 5 : 1 or from about 3 : 1 to about 1:2, preferably to about 1 : 1.5, to about 1 : 1.25, to about 1: 1.2, to about 1: 1.15, to about 1: 1.1, to about 1: 1.05 or more preferably to about 1: 1. In particular, the ratio is preferably from about 15: 1 to about 1: 1.5, more preferably from about 10: 1, even more preferably from about 5: 1 or from about 3: 1 to about 1: 1.25, to about 1: 1.2, to about 1: 1.1, or more preferably to about 1: 1. Optimized amounts and ratios may vary depending, for example, on the application, the desired properties of the product, and the like.

[0028] The antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) may collectively constitute from about 50 wt% to about 100 wt% of the active ingredients in the stabilized antimicrobial composition, typically a majority (>50 wt%) of the active ingredients, such as at least 60 wt% or at least 70 wt%, preferably at least 80 wt%, more preferably at least 85 wt%, at least 90 wt%, at least 95 wt%, at least 96 wt%, at least 97 wt%, at least 98 wt% or at least 99 wt%, based on the total weight of active ingredients in the antimicrobial composition. The stabilized antimicrobial composition often contains from about 60 to 100 wt%, preferably from about 65 to 100 wt%, from about 70 to 100 wt%, from about 75 to 100 wt%, from about 80 to 100 wt%, from about 85 to 100 wt%, from about 90 to 100 wt%, or from about 95 or from about 97 to 100 wt%, of the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) combined, based on the total weight of active ingredients in the antimicrobial composition. In many embodiments, the stabilized antimicrobial composition comprises active ingredients consisting essentially of, or in further embodiments consisting of, the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b).

[0029] One or more than one additional antimicrobial agent (d), such as antimicrobial agents suitable for use in personal care formulations or home care formulations, may be present in the stabilized antimicrobial composition, and, if present, constitutes less than 50 wt% of the active ingredients in the antimicrobial composition, such as no greater than 40 wt% or no greater than 30 wt%, preferably no greater than 25 wt%, no greater than 20 wt%, more preferably no greater than 15 wt%, no greater than 10 wt%, no greater than 5 wt%, or no greater than 3 wt%, based on the total weight of active ingredients in the antimicrobial composition.

[0030] Preferably, the stabilized antimicrobial composition contains from about 70 to 100 wt%, from about 75 to 100 wt%, from about 80 to 100 wt%, from about 85 to 100 wt%, from about 90 to 100 wt%, or from about 95 or from about 97 to 100 wt%, of the antimicrobial agent (a), the at least one saturated straight-chain fatty acid and / or salt thereof (b) and the one or more than one additional antimicrobial agent (d) combined, based on the total weight of active ingredients in the antimicrobial composition. Preferably, the antimicrobial agent (a), the at least one saturated straight-chain fatty acid and / or salt thereof (b) and the one or more than one additional antimicrobial agent (d) constitute all or substantially all of the active ingredients in the stabilized antimicrobial composition. In many embodiments, the stabilized antimicrobial composition comprises active ingredients consisting essentially of, or in further embodiments consisting of, the antimicrobial agent (a), the at least one saturated straight-chain fatty acid and / or salt thereof (b) and the one or more than one additional antimicrobial agent (d).

[0031] The antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) collectively constitute from about 50 wt% to about 99.8 wt% of the total weight of the stabilized antimicrobial composition, typically a majority (>50 wt%) of the antimicrobial composition, such as at least 60 wt%, preferably at least 70 wt%, more preferably at least 75 wt%, at least 80 wt%, even more preferably at least 85 wt%, or at least 90 wt%, up to about 99.8 wt%, based on the total weight of the antimicrobial composition. The stabilized antimicrobial composition often contains from about 60 wt%, preferably from about 70 wt%, more preferably from about 75 wt%, from about 80 wt% or even more preferably from about 85 wt% to about 99 wt%, preferably to about 97 wt%, more preferably to about 95 wt%, or to about 92 wt%, of the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) combined, based on the total weight of the antimicrobial composition. In many embodiments, the stabilized antimicrobial composition consists essentially of, or in further embodiments consists of, the antimicrobial agent (a), the at least one saturated straight-chain fatty acid and / or salt thereof (b) and the at least one alkaline stabilizer (c).

[0032] Where the stabilized antimicrobial composition includes the one or more than one additional antimicrobial agent (d), the one or more than one additional antimicrobial agent (d) preferably constitutes no greater than 45 wt% of the total weight of the stabilized antimicrobial composition, typically no greater than 40 wt% or no greater than 30 wt%, preferably no greater than 25 wt%, no greater than 20 wt%, more preferably no greater than 15 wt%, no greater than 10 wt%, no greater than 5 wt%, or no greater than 3 wt%, based on the total weight of the antimicrobial composition.

[0033] The stabilized antimicrobial composition may preferably contain from about 70 wt%, more preferably from about 75 wt%, from about 80 wt% or from about 85 wt% to about 99 wt%, preferably to about 97 wt%, more preferably to about 95 wt%, or to about 92 wt%, of the antimicrobial agent (a), the at least one saturated straight-chain fatty acid and / or salt thereof (b) and the one or more than one additional antimicrobial agent (d) combined, based on the total weight of the antimicrobial composition. The antimicrobial agent (a), the at least one saturated straight-chain fatty acid and / or salt thereof (b), the at least one alkaline stabilizer (c), and the one or more than one additional antimicrobial agent (d) may constitute all or substantially all of the ingredients in the stabilized antimicrobial composition. In many embodiments, the stabilized antimicrobial composition consists essentially of, or in further embodiments consists of, the antimicrobial agent (a), the at least one saturated straight-chain fatty acid and / or salt thereof (b), the at least one alkaline stabilizer (c), and the one or more than one additional antimicrobial agent (d).

[0034] The ratio by weight of the combined amount of (a) and (b) to the amount of the one or more than one additional antimicrobial agent (d) typically ranges from about 1: 1 to about 150: 1, such as from about 1.1: 1, from about 1.2: 1, from about 1.5: 1, from about 2: 1, from about 3: 1, from about 4: 1, preferably from about 5: 1, from about 9: 1, more preferably from about 12: 1, from about 16: 1, particularly preferably from about 20: 1 to about 150: 1, preferably to about 100: 1, more preferably to about 75: 1 or to about 50: 1.

[0035] In accordance with the present disclosure, it was found that the stability over time of the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) in an antimicrobial composition can be significantly enhanced via the inclusion of the alkaline stabilizer (c). The alkaline stabilizer comprises a base preferably chosen from a metal (preferably an alkali metal or alkaline earth metal) hydroxide, oxide, carbonate, bicarbonate, phosphate, or hydride, an amine base or a combination thereof, more preferably a metal hydroxide. The metals are preferably chosen from sodium, potassium, magnesium and calcium. In many preferred embodiments, the alkaline stabilizer comprises sodium hydroxide, potassium hydroxide or a combination thereof. In particular, the alkaline stabilizer may be chosen to ensure compatibility or suitability for a desired end application or end product formulation, e.g., in a personal care formulation (e.g., a cosmetically acceptable alkaline stabilizer) or a home care formulation. The base of the alkaline stabilizer may be present, for example, in an amount of from about 0.1 wt%, from about 0.3 wt%, preferably from about 0.5 wt%, more preferably from about 1 wt% or from about 3 wt% to about 10 wt%, preferably to about 8 wt% or to about 6 wt%, based on the total weight of the antimicrobial composition. Typically, the alkaline stabilizer is in the form of an alkaline solution, preferably an alkaline aqueous solution. For example, the alkaline solution, such as a metal hydroxide solution (e.g., where the metal hydroxide comprises potassium hydroxide, sodium hydroxide or a combination thereof), may have a strength of the base component in the solution of from about 1% to about 90%, to about 80%, to about 70% or to about 60% (w / w), preferably from about 10%, from about 20% or from about 30% to about 70%, to about 60% or to about 50% (w / w). Higher strength alkaline solutions may also be used. Preferably, the alkaline stabilizer has a pH ranging from about 9.0, more preferably from about 10.0 to about 14.0, such as from about 11.0 or from about 12.0 to about 14.0 or to about 13.0. The antimicrobial composition with the alkaline stabilizer preferably has a pH ranging from about 5.0 to about 7.5, more preferably from about 5.5 or from about 6.0 to about 7.5, to about 7.0 or to about 6.5. The alkaline stabilizer typically constitutes from about 0.2 wt%, from about 0.5 wt%, or from about 1 wt% to about 25 wt%, preferably from about 1 wt% more preferably from about 3 wt% or from about 5 wt% to about 20 wt% or to about 15 wt%, such as from about 5 wt% or from about 8 wt% to about 15 wt% or to about 12 wt%, based on the total weight of the antimicrobial composition. As shown in the Examples section, the stabilized antimicrobial composition preferably exhibits < 5 wt% loss of the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid (and / or salt thereof) (b) combined when stored at 55 °C for 2 weeks. As further shown in the Examples section, the stabilized antimicrobial composition preferably exhibits < 15 wt% loss, more preferably < 10 wt% loss, even more preferably < 5 wt% loss, of the antimicrobial agent (a) and the at least one saturated straightchain fatty acid (and / or salt thereof) (b) combined when stored at 55 °C for 5 weeks.

[0036] The stabilized antimicrobial composition of the present disclosure may, but need not, comprise added solvent (e). In many embodiments, the stabilized antimicrobial composition is free or substantially free of solvent. Preferably, the amount of the at least one saturated straight-chain fatty acid and / or salt thereof (b) does not exceed a ratio of the antimicrobial agent (a) to the at least one fatty acid and / or salt thereof (b) of 1 :2.5, such as not exceeding 1:2, not exceeding 1 : 1.5 or not exceeding 1 : 1.25.

[0037] If present, the one or more than one solvent (e) typically constitutes from about 10 wt%, from about 20 wt% or from about 30 wt% to less than 50 wt%, based on the total weight of the stabilized antimicrobial composition. Solvents may be chosen according to their compatibility or suitability for a desired end application or end product formulation, e.g., in a personal care formulation (e.g., a cosmetically acceptable solvent) or a home care formulation. Suitable solvents include, but are not limited to, water, C1-C4 alcohols, C1-C4 diols (e.g., glycols), glycerin and the like.

[0038] The stabilized antimicrobial composition may, but need not, contain one or more excipients (f), typically in minor quantities. Excipients may similarly be chosen according to their compatibility or suitability for a desired end application or end product formulation, e.g., in a personal care formulation (e.g., a cosmetically acceptable excipient) or a home care formulation. Examples of the excipients (f) include, but are not limited to, dispersants, solubilizers, buffers, and / or stabilizers (other than the alkaline stabilizer (c)). In many embodiments, the stabilized antimicrobial composition is free or substantially free of solubilizing or miscibility agents.

[0039] The stabilized antimicrobial composition may comprise one or more excipients (f), for example, from 0 to about 10 wt%, such as from about 0.001 wt%, from about 0.01 wt%, from about 0.05 wt% or from about 0.1 wt% to about 5 wt%, to about 3 wt%, or to about 1 wt%, based on the total weight of the antimicrobial composition. For example, the component (e) may range from 0 to about 5 wt%, from 0 to about 3 wt% from about 0.01 to about 5 wt%, from about 0. 1 to about 5 wt%, from about 0.01 to about 3 wt%, from about 0. 1 to about 3 wt%, from about 0.01 to about 1 wt%, or from about 0. 1 to about 1 wt%.

[0040] In general, the stabilized antimicrobial composition may comprise a combined amount of the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) of from about 50 to 99.8 wt%, such as from about 60 wt% to about 99 wt%, to about 97 wt%, to about 95 wt%, to about 92 wt%, to about 85 wt%, to about 80 wt%, or to about 70 wt%, based on the total weight of the antimicrobial composition; the at least one alkaline stabilizer (c) in an amount of from about 0.2, from about 0.5, or from about 1 wt% to about 25 wt%, preferably from about 3 wt%, more preferably from about 5 wt% to about 20 wt%, such as from about 5 wt% or from about 8 wt% to about 15 wt% or to about 12 wt%, based on the total weight of the antimicrobial composition; optionally one or more than one additional antimicrobial agent (d), typically at a weight ratio of the combined amount of (a) and (b) to the amount of (d) as described herein; optionally one or more solvents (e) in an amount from 0 to less than 50 wt%, such as from about 10 wt% or from about 20 wt% to about 45 wt% or to about 40 wt%, based on the total weight of the antimicrobial composition; and optionally one or more excipients (f) in an amount from about 0 to about 10 wt%, such as from about 0.001 wt%, from about 0.01 wt%, from about 0.05 wt% or from about 0.1 wt% to about 5 wt%, to about 3 wt%, or to about 1 wt%, based on the total weight of the antimicrobial composition.

[0041] In many embodiments, the stabilized antimicrobial composition consists essentially of, or in further embodiments consists of, the antimicrobial agent (a), the at least one saturated straight-chain fatty acid and / or salt thereof (b), the at least one alkaline stabilizer (c), optionally one or more than one additional antimicrobial agent (d), optionally one or more than one solvent (e) and optionally one or more than one excipient (f). In many embodiments, the stabilized antimicrobial composition consists essentially of, or in further embodiments consists of, the antimicrobial agent (a), the at least one saturated straight-chain fatty acid and / or salt thereof (b), the at least one alkaline stabilizer (c), one or more than one additional antimicrobial agent (d), optionally one or more than one solvent (e) and optionally one or more than one excipient (f).

[0042] The one or more than one additional antimicrobial agent (d) of the present disclosure may be chosen based on suitability for the intended application, such as in personal care or home care formulations, and are preferably suitably selected to be sufficiently soluble with the combination of the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) either in the absence of any added solvent or in a chosen solvent for the antimicrobial composition.

[0043] Examples of the additional antimicrobial agents (d) include, but are not limited to, alkylhydroxamic acids and / or salts thereof, aromatic aldehydes (e.g., cinnamic aldehyde), aromatic alcohols (e.g., cinnamic alcohol, dichlorobenzyl alcohol, phenolic compounds, such as hydroxyacetophenone), diols (e.g., glycols, such as 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2- heptanediol, and 1,2-octanediol (i.e., caprylyl glycol), bronopol), glyceryl ethers (e.g., ethylhexylglycerin, chlorphenesin), isothiazolinones (e.g., methylisothiazolinone, chloromethylisothiazolinone, benzisothiazolinone), fatty acids having carbon chain lengths outside the range of the component (b) herein and / or salts thereof, pyrithiones (e.g., zinc pyrithione, sodium pyrithione) and combinations thereof. It shall be understood that the scope of the one or more than one additional antimicrobial agent (d) does not include the antimicrobial agent (a) or the at least one fatty acid and / or salt thereof (b). Examples of suitable alkylhydroxamic acids and salts thereof include those having at least one alkyl group of a chain length of from about 2 to about 22 carbon atoms, which may be branched or linear in structure, substituted (e.g., alkoxy and the like) or unsubstituted, and saturated or unsaturated (e.g., alkenyl, alkynyl, alkenoxy, alkynoxy and the like). For example, the carbon chains may be interrupted by one or more oxygen atoms and / or may contain one or more side- and / or terminal -hydroxy group substituents. Other functional groups, particularly groups compatible with or suggested for use in personal care or home care formulations, may be used. Preferably, the alkylhydroxamic acids and / or salts thereof contain alkyl groups having a chain length, often linear, of about 6 to about 12 carbon atoms. Examples of suitable alkylhydroxamic acids and salts thereof include hexanohydroxamic acid, caprylhydroxamic acid, decanohydroxamic acid, laurohydroxamic acid and salts and combinations thereof, preferably caprylhydroxamic acid and / or a salt thereof. More than one alkylhydroxamic acid and / or salt thereof may be used.

[0044] The one or more than one additional antimicrobial agent (d) preferably comprises an alkylhydroxamic acid and / or salt thereof (preferably, hexanohydroxamic acid, caprylhydroxamic acid, decanohydroxamic acid, laurohydroxamic acid and / or salt thereof or combination thereof, particularly caprylhydroxamic acid and / or salt thereof), hydroxyacetophenone, dichlorobenzyl alcohol, cinnamic aldehyde, cinnamic alcohol, 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2- heptanediol, 1,2-octanediol (i.e., caprylyl glycol), bronopol, ethylhexylglycerin, chlorphenesin, methylisothiazolinone, chloromethylisothiazolinone, benzisothiazolinone, zinc pyrithione, sodium pyrithione or a combination thereof.

[0045] More preferably, the one or more than one additional antimicrobial agent (d) comprises an alkylhydroxamic acid and / or salt thereof (such as an exemplary alkylhydroxamic acid and / or salt thereof as described herein, most preferably caprylhydroxamic acid and / or salt thereof), cinnamic aldehyde, zinc pyrithione, sodium pyrithione or a combination thereof.

[0046] In particularly preferred embodiments, the one or more than one additional antimicrobial agent (d) comprises or is an alkylhydroxamic acid and / or salt thereof, such as any exemplary alkylhydroxamic acid and / or salt thereof as described herein, preferably caprylhydroxamic acid and / or a salt thereof.

[0047] The present disclosure is not limited to any particular technique for preparing the stabilized antimicrobial composition and such composition may be prepared in any suitable manner for combining or mixing the components described herein.

[0048] The present disclosure provides for the use of an antimicrobial effective amount of the presently disclosed stabilized antimicrobial composition in a wide range of product formulations and applications, such as for use in personal care (e.g., cosmetic), home care, health care (such as pharmaceutical (i.e., having at least one active pharmaceutical ingredient) or other health care products) or industrial product formulations, particularly formulations for use as a personal care or home care product. Examples include, without limitation, household products and cleaners, fabric detergents, dish detergents, cleansers, soaps, bubble baths, disinfectants, deodorizers, pharmaceutical products, cosmetics, hygiene compositions, infant care products, antimicrobial soaps, hand sanitizers, deodorants, antiperspirants, anti-microbial coatings, wound care compositions, dermatological compositions, skin conditioners, skin moisturizers, anti-wrinkle formulations, sunscreens, tanning lotions, hair products, shampoos, shower gels, bubble baths, conditioners, shaving creams, etc. Depending on the application, the product formulation may contain numerous and different compatible ingredients. In many embodiments, the product formulation comprises an antimicrobial effective amount of the stabilized antimicrobial composition of the present disclosure and one or more additional ingredients suitable for use in a personal care (e.g., cosmetic), home care, health care, or industrial product formulation, particularly a personal care or home care formulation.

[0049] In one aspect, an aqueous product formulation comprises an antimicrobial effective amount of the stabilized antimicrobial composition of the present disclosure. Preferably, the aqueous product formulation is a personal care (e.g., cosmetic), home care, health care, or industrial product formulation, particularly a personal care or home care formulation.

[0050] The aqueous product formulation typically has a pH ranging from about 3, from about 4, from about 5, from about 5.5, from about 6 or from about 6.5 to about 12 or to about 11, such as from about 3 to about 10, from about 3 to about 8.5, from about 4 to about 8.5, from about 3 to about 8, from about 4 to about 8, from about 3 to about 7.5, from about 4 to about 7.5 or from about 5 to about 7.5. The selected pH will vary depending, for example, on the particular end use application (e.g., home care or personal care applications). In many embodiments, the aqueous product formulation has a pH ranging from about 5.0, from about 5.1, from about 5.2, from about 5.3, from about 5.4, from about 5.5, from about 5.6, from about 5.7, from about 5.8, from about 5.9, from about 6.0, from about 6.1, from about 6.2, from about 6.3, from about 6.4 or from about 6.5 to about 12, to about 11, to about 10, to about 9.5, to about 9.0, to about 8.5, to about 8.4, to about 8.3, to about 8.2, to about 8. 1, to about 8.0, to about 7.9, to about 7.8, to about 7.7, to about 7.6 or to about 7.5. The pH may range, for example, from about 5.0, from about 5.5, from about 6.0 or from about 6.5 to about 12, to about 11, to about 10, to about 9, to about 8.5, to about 8.0 or to about 7.5. In many embodiments, the pH is higher than 5.0, higher than 5.5, higher than 6.0, or higherthan 6.5, preferably up to about 11, up to about 10, up to about 9.0, up to about 8.5, up to about 8.0 or up to about 7.5.

[0051] The pH of the aqueous product formulation is more preferably at least 6.0, even more preferably higher than 6.0, such as a pH of at least 6. 1, at least 6.3, most preferably at least 6.5, at least 6.7, at least 6.9, at least 7.0, at least 7.1, at least 7.2, at least 7.3, at least 7.4, or at least 7.5. The pH of the aqueous product formulation may be up to about 12, preferably up to about 11 or up to about 10.

[0052] In general, the antimicrobial effective amount of the stabilized antimicrobial composition provides from about 0.05 wt%, preferably from about 0. 1 wt%, more preferably from about 0.2 wt%, from about 0.3 wt%, from about 0.4 wt% or from about 0.5 wt% to about 5 wt%, to about 4 wt%, preferably to about 3 wt%, to about 2.5 wt%, more preferably to about 2 wt%, to about 1.5 wt% or to about 1 wt% of the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) combined, based on the total weight of the formulation, and the formulation may optionally comprise one or more than one additional antimicrobial agent (d), preferably in the ratio by weight of the combined amount of (a) and (b) to the amount of (d) as described herein. If the optional component (d) is included (preferably in the ratio by weight of the combined amount of (a) and (b) to the amount of (d) as described herein), the antimicrobial effective amount of the stabilized antimicrobial composition may provide, for example, from about 0.2 wt%, from about 0.3 wt%, from about 0.4 wt% or from about 0.5 wt% to about 6 wt%, to about 5 wt%, to about 4 wt%, preferably to about 3 wt%, more preferably to about 2 wt% or to about 1 wt% of components (a), (b) and (d) combined, based on the total weight of the formulation. Typically, the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) each is present in the product formulation in an amount not exceeding 3 wt%, preferably not exceeding 2 wt%, not exceeding 1.5 wt% or not exceeding 1 wt%, based on the total weight of the formulation. In many embodiments, each is present below 1 wt%. Preferably, the combined amount of the antimicrobial agent (a), the at least one saturated straight-chain fatty acid and / or salt thereof (b) and, if used, the optional one or more than one additional antimicrobial agent (d) ranges from about 2 wt% or less (e.g., from about 0.1 wt%, from about 0.2 wt% or from about 0.3 wt% to about 2 wt%), from about 1.5 wt% or less (e.g., from about 0.1 wt%, from about 0.2 wt% or from about 0.3 wt% to about 1.5 wt%), from about 1.2 wt% or less (e.g., from about 0.1 wt%, from about 0.2 wt% or from about 0.3 wt% to about 1.2 wt%) or from about 1 wt% or less (e.g., from about 0.1 wt%, from about 0.2 wt% or from about 0.3 wt% to about 1 wt%), based on the total weight of the formulation. In many embodiments, the product formulation comprises no greater than 1.5 wt%, preferably no greater than 1 wt%, no greater than 0.9 wt%, no greater than 0.8 wt%, no greater than 0.7 wt%, no greater than 0.6 wt%, more preferably no greater than 0.5 wt%, no greater than 0.4 wt% or no greater than 0.3 wt% of the antimicrobial agent (a). Preferably, the formulation comprises no greater than 0.5 wt%, no greater than 0.4 wt%, no greater than 0.3 wt%, more preferably no greater than 0.2 wt%, even more preferably no greater than 0. 1 wt% or no greater than 0.05 wt% of the one or more than one additional antimicrobial agent (d).

[0053] The product formulation may comprise, for example, the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) in a combined antimicrobial effective amount of from about 0.2 wt%, from about 0.3 wt%, from about 0.4 wt% or from about 0.5 wt% to about 5 wt%, preferably to about 3 wt%, more preferably to about 2 wt%, to about 1.5 wt% or to about 1 wt%, based on the total weight of the formulation, and further comprise the one or more than one additional antimicrobial agent (d), wherein the ratio by weight of the combined amount of (a) and (b) to the amount of (d) ranges from about 1 : 1 to about 150: 1, such as from about 1.1: 1, from about 1.2: 1, from about 1.5: 1, from about 2: 1, from about 3: 1, from about 4: 1, preferably from about 5: 1, from about 9: 1, more preferably from about 12: 1, from about 16: 1, particularly preferably from about 20: 1 to about 150: 1, preferably to about 100: 1, more preferably to about 75 : 1 or to about 50: 1. Preferably, the one or more than one additional antimicrobial agent (d) is at least one alkylhydroxamic acid as described herein and / or a salt thereof, more preferably caprylhydroxamic acid and / or a salt thereof.

[0054] The product formulation may comprise, for example, the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) in a combined antimicrobial effective amount of from about 0.2 wt%, from about 0.3 wt%, from about 0.4 wt% or from about 0.5 wt% to about 5 wt%, preferably to about 3 wt%, more preferably to about 2 wt%, to about 1.5 wt% or to about 1 wt%, and may further comprise the one or more than one additional antimicrobial agent (d) in an amount less than or equal to about 0.2 wt%, such as no greater than 0.15 wt%, no greater than 0. 1 wt% or no greater than 0.05 wt%, each based on the total weight of the formulation. Preferably, the one or more than one additional antimicrobial agent (d) is at least one alkylhydroxamic acid as described herein and / or a salt thereof, more preferably caprylhydroxamic acid and / or a salt thereof.

[0055] In a further aspect of the present disclosure, a personal care or home care product formulation comprises an antimicrobial effective amount of a combination of an antimicrobial agent selected from the group consisting of phenoxyethanol, benzyl alcohol and combinations thereof, at least one saturated straight-chain fatty acid having a carbon chain length of from six to twelve carbon atoms and / or a salt thereof, and one or more additional ingredients suitable for use in a personal care or home care product formulation, wherein the ratio by weight of the antimicrobial agent to the at least one saturated straight-chain fatty acid and / or salt thereof is from about 40: 1 to about 1:5, preferably from about 40: 1 or from about 20: 1 to about 1:2.5, and wherein the product formulation has a pH of at least 6.0, more preferably having a pH higher than 6.0, such as a pH of at least 6. 1, at least 6.3, more preferably at least 6.5, at least 6.7, at least 6.9, at least 7.0, at least 7. 1, at least 7.2, at least 7.3, at least 7.4, or at least 7.5.

[0056] In a further aspect, a method of preserving or inhibiting the growth of microorganisms in a personal care or home care product formulation, comprises adding to the product formulation an antimicrobial agent selected from the group consisting of phenoxyethanol, benzyl alcohol and combinations thereof, and at least one saturated straight-chain fatty acid having a carbon chain length of from six to twelve carbon atoms and / or a salt thereof, wherein the antimicrobial agent and the at least one saturated straight-chain fatty acid and / or salt thereof are present in the formulation in a combined antimicrobial effective amount, the ratio by weight of the antimicrobial agent to the at least one fatty acid and / or salt thereof is from about 40: 1 to about 1:5, preferably from about 40: 1 or from about 20: 1 to about 1:2.5, and the product formulation has a pH of at least 6.0, more preferably having a pH higher than 6.0, such as a pH of at least 6. 1, at least 6.3, more preferably at least 6.5, at least 6.7, at least 6.9, at least 7.0, at least 7.1, at least 7.2, at least 7.3, at least 7.4, or at least 7.5.

[0057] In another aspect, the present disclosure provides for the use of at least one saturated straight-chain fatty acid having a carbon chain length of from six to twelve carbon atoms and / or a salt thereof to enhance the antimicrobial efficacy of an antimicrobial agent selected from the group consisting of phenoxyethanol, benzyl alcohol and combinations thereof in a personal care or home care product formulation having a pH of at least 6.0, more preferably having a pH higher than 6.0, such as a pH of at least 6. 1, at least 6.3, more preferably at least 6.5, at least 6.7, at least 6.9, at least 7.0, at least 7.1, at least 7.2, at least 7.3, at least 7.4, or at least 7.5.

[0058] As demonstrated herein, it was discovered that saturated straight-chain fatty acids having a carbon chain length of from six to twelve carbon atoms and / or salts thereof surprisingly boost the antimicrobial activity (e.g., an antibacterial and / or antifungal effect) of phenoxyethanol, benzyl alcohol or a combination thereof in personal care and home care product formulations having a pH of at least 6.0, more preferably having a pH higher than 6.0, such as a pH of at least 6. 1, at least 6.3, more preferably at least 6.5, at least 6.7, at least 6.9, at least 7.0, at least 7.1, at least 7.2, at least 7.3, at least 7.4, or at least 7.5. The antimicrobial activity of phenoxyethanol, benzyl alcohol or a combination thereof is significantly enhanced against various microorganisms, including bacteria and fungi. For example, the presently disclosed combination preferably controls gram positive bacteria, gram negative bacteria, and fungi, among other microorganisms. Non-limiting examples include Staphylococcus aureus, Staphylococcus epidermidis. Pseudomonas aeruginosa, Escherichia coli, Enterobacter gergoviae, Klebsiella pneumoniae, Burholderia cepacia, Pseudomonas putida, Candida albicans, Aspergillus brasiliensis, and mixtures thereof.

[0059] The pH of the personal care or home care product formulations is preferably up to about 8.0 in the case of personal care formulations and preferably up to about 12 or up to about 11 in the case of home care formulations.

[0060] As a particular example, the product formulation may be any number and variety of different personal care products, such as cosmetic products. The personal care formulation may be, for example, any formulation for skin care, hair care, cosmetics, personal cleaning, hygiene, sun protection and other personal care applications. Examples of such products include, without limitation, skin toners, skin cleansers, night creams, skin creams, shaving creams, skin lotions, makeup, mascara, lipstick, blush, gloss, eye-liner, makeup removers, sunscreens, lip balms, fragrances, massage oils, shampoos, conditioners, hair styling gels, hair reparatives, hair tonics, hair fixatives, hair mousses, bath and shower gels, liquid soaps, moisturizing sprays, bath additives, ophthalmic preparations, foaming soaps and body washes, liquids for any personal care wet wipe application, etc.

[0061] Depending on the application, the personal care product formulation may contain numerous and different compatible ingredients. A personal care formulation may contain, for example, any of solvents, surfactants, emulsifiers, chelating agents, oxidizing agents, colorants, rheology modifiers, conditioners, emollients, skin care ingredients, moisturizers, thickeners, humectants, fillers, antioxidants, active ingredients, such as dermatologically active ingredients typically suited for topical application, fragrances, etc.

[0062] As a further example, the product formulation may be any number and variety of different home care products, such as fabric care products and cleaning products. Examples include dish soaps, laundry detergents, cleaning wipes, cleaning formulations and other home care applications.

[0063] Depending on the application, the home care product formulation may contain, for example, any of cleaning agents, detergents, emulsifiers, surfactants, thickeners, gelling agents, bleaches, whiteners, deodorizers, enzymes, stabilizers, fragrances, soil-release agents, anti-shrinking agents, anti-wrinkle agents, anti-spotting agents, antioxidants, UV absorbing compounds, anti -corrosion agents, anti-static agents, ironing aids, odor-preventing compounds, etc.

[0064] Examples of the foregoing ingredients and other agents used in personal care and home care product compositions are known in the art.

[0065] The product formulations of the present disclosure may be of a variety of different forms, for example, liquids, pastes, serums, hydrogels, creams, emulsions, lotions, gels, oils, wipes, ointments, semi-solid compositions, foams and aerosol sprays. The product formulations may be leave-on or rinse-off formulations. The product formulations may be hair care products, such as shampoos, hair conditioners, hair dyes, hair tonic, hair gel, hair dressings, hair grooming aids and other hair care preparations; products for shaving applications such as shaving cream, aftershave lotions, and other shaving applications; personal cleaners for the body and hands, such as liquid bath soaps and detergents; fragrance preparations, such as perfumes, after bath splashes, and other similar fragrant preparations, skin care products, such as moisturizers, creams, and lotions and other similar skin care products, make-up products, such as mascara, base foundations and the like; make-up removal products, sun care products, indoor tanning products and other similar personal care products. The product formulations may be liquids used to saturate wipes for personal cleaning and hygiene, for example baby wipes, wet toilet wipes, make-up removal wipes and exfoliating wipes the like, or wet wipe formulations for home care.

[0066] The product formulations may further comprise one or more than one additional antimicrobial agent as described herein.

[0067] An optimal ratio of the phenoxyethanol, benzyl alcohol or combination thereof to the at least one saturated straight-chain fatty acid and / or salt thereof, an optimal ratio of the above two components to the amount of one or more additional antimicrobial agents (if used) as described herein, and an optimal antimicrobial effective amount of the combination of the phenoxyethanol, benzyl alcohol or combination thereof and the at least one saturated straight-chain fatty acid and / or salt thereof may vary depending, for example, on the particular components selected, the end use application, the desired level of antimicrobial activity, the final properties of the product, and the like. As known in the art, an antimicrobial effect may be demonstrated by various suitable antimicrobial effectiveness tests.

[0068] In general, the antimicrobial effective amount of the combination of the phenoxyethanol, benzyl alcohol or combination thereof and the at least one saturated straight-chain fatty acid and / or salt thereof is from about 0.05 wt%, preferably from about 0.1 wt%, more preferably from about 0.2 wt%, from about 0.3 wt%, from about 0.4 wt% or from about 0.5 wt% to about 5 wt%, to about 4 wt%, preferably to about 3 wt%, to about 2.5 wt%, more preferably to about 2 wt%, to about 1.5 wt% or to about 1 wt%, based on the total weight of the formulation, and the formulation may optionally comprise one or more than one additional antimicrobial agent as described herein, preferably in the ratios by weight as described herein. If the one or more than one additional antimicrobial agent is included (preferably in the ratios by weight as described herein), product formulations may contain, for example, from about 0.2 wt%, from about 0.3 wt%, from about 0.4 wt% or from about 0.5 wt% to about 6 wt%, to about 5 wt%, to about 4 wt%, preferably to about 3 wt%, more preferably to about 2 wt% or to about 1 wt% of the combination of phenoxyethanol, benzyl alcohol or a combination thereof, the at least one saturated straight-chain fatty acid and / or salt thereof, and the one or more additional antimicrobial agents, based on the total weight of the formulation. Typically, the phenoxyethanol, benzyl alcohol or combination thereof and the at least one saturated straight-chain faty acid and / or salt thereof each is present in the product formulation in an amount not exceeding 3 wt%, preferably not exceeding 2 wt%, not exceeding 1.5 wt% or not exceeding 1 wt%, based on the total weight of the formulation. In many embodiments, each is present below 1 wt%. Preferably, the combined amount of the phenoxyethanol, benzyl alcohol or combination thereof, the at least one saturated straight-chain faty acid and / or salt thereof and, if used, the optional one or more than one additional antimicrobial agent ranges from about 2 wt% or less (e.g., from about 0. 1 wt%, from about 0.2 wt% or from about 0.3 wt% to about 2 wt%), from about 1.5 wt% or less (e.g., from about 0. 1 wt%, from about 0.2 wt% or from about 0.3 wt% to about 1.5 wt%), from about 1.2 wt% or less (e.g., from about 0.1 wt%, from about 0.2 wt% or from about 0.3 wt% to about 1.2 wt%) or from about 1 wt% or less (e.g., from about 0.1 wt%, from about 0.2 wt% or from about 0.3 wt% to about 1 wt%), based on the total weight of the formulation. In many embodiments, the product formulation comprises no greater than 1.5 wt%, preferably no greater than 1 wt%, no greater than 0.9 wt%, no greater than 0.8 wt%, no greater than 0.7 wt%, no greater than 0.6 wt%, more preferably no greater than 0.5 wt%, no greater than 0.4 wt% or no greater than 0.3 wt% of the phenoxyethanol, benzyl alcohol or combination thereof. Preferably, the formulation comprises no greater than 0.5 wt%, no greater than 0.4 wt%, no greater than 0.3 wt%, more preferably no greater than 0.2 wt%, even more preferably no greater than 0.1 wt% or no greater than 0.05 wt% of the one or more than one additional antimicrobial agent.

[0069] The product formulation may comprise, for example, the phenoxyethanol, benzyl alcohol or combination thereof and the at least one saturated straight-chain faty acid and / or salt thereof in a combined antimicrobial effective amount of from about 0.2 wt%, from about 0.3 wt%, from about 0.4 wt% or from about 0.5 wt% to about 5 wt%, preferably to about 3 wt%, more preferably to about 2 wt%, to about 1.5 wt% or to about 1 wt%, based on the total weight of the formulation, and further comprise the one or more than one additional antimicrobial agent, wherein the ratio by weight of the combined amount of the phenoxyethanol, benzyl alcohol or combination thereof and the least one saturated straight-chain faty acid and / or salt thereof to the amount of the one or more additional antimicrobial agents ranges from about 1: 1 to about 150: 1, such as from about 1.1: 1, from about 1.2: 1, from about 1.5: 1, from about 2: 1, from about 3: 1, from about 4: 1, preferably from about 5: 1, from about 9: 1, more preferably from about 12: 1, from about 16: 1, particularly preferably from about 20: 1 to about 150: 1, preferably to about 100: 1, more preferably to about 75: 1 or to about 50: 1 . Preferably, the one or more than one additional antimicrobial agent is at least one alkylhydroxamic acid as described herein and / or a salt thereof, more preferably caprylhydroxamic acid and / or a salt thereof.

[0070] The product formulation may comprise, for example, the phenoxyethanol, benzyl alcohol or combination thereof and the at least one saturated straight-chain faty acid and / or salt thereof in a combined antimicrobial effective amount of from about 0.2 wt%, from about 0.3 wt%, from about 0.4 wt% or from about 0.5 wt% to about 5 wt%, preferably to about 3 wt%, more preferably to about 2 wt%, to about 1.5 wt% or to about 1 wt%, and further comprise the one or more than one additional antimicrobial agent in an amount less than or equal to about 0.2 wt%, such as no greater than 0.15 wt%, no greater than 0. 1 wt% or no greater than 0.05 wt%, each based on the total weight of the formulation. Preferably, the one or more than one additional antimicrobial agent is at least one alkylhydroxamic acid as described herein and / or a salt thereof, more preferably caprylhydroxamic acid and / or a salt thereof.

[0071] The present disclosure is not limited to any particular technique for preparing a product formulation, and the components thereof may be added in any suitable manner. For example, phenoxyethanol, benzyl alcohol or a combination thereof, the at least one saturated straight-chain fatty acid and / or salt thereof, the optional one or more than one additional antimicrobial agent and the other ingredients as described herein can be applied to a product formulation as a mixture or applied individually to the formulation at the same time or in any order.

[0072] In the compositions, formulations, methods and uses of the present disclosure, the at least one saturated straight-chain fatty acid (and / or salt) thereof can be essentially a single saturated straightchain fatty acid (and / or salt thereof) having a carbon chain length of from six to twelve, preferably from six to ten, carbon atoms or can be any mixture of saturated straight-chain fatty acids (and / or salts thereof) having carbon chain lengths within the range of from six to twelve, preferably from six to ten, carbon atoms. For example, the at least one saturated straight-chain fatty acid and / or salt thereof may comprise caproic acid and / or a salt thereof. In another example, the at least one saturated straightchain fatty acid and / or salt thereof comprises heptanoic acid and / or a salt thereof. In a further example, the at least one saturated straight-chain fatty acid and / or salt thereof comprises caprylic acid and / or a salt thereof. In another example, the at least one saturated straight-chain fatty acid and / or salt thereof comprises pelargonic acid and / or a salt thereof. In a further example, the at least one saturated straight-chain fatty acid and / or salt thereof comprises capric acid and / or a salt thereof. In a further example, the at least one saturated straight-chain fatty acid and / or salt thereof comprises undecanoic acid and / or a salt thereof. In another example, the at least one saturated straight-chain fatty acid and / or salt thereof comprises lauric acid and / or a salt thereof. For example, a majority, essentially all or all of the at least one saturated straight-chain fatty acid and / or salt thereof by weight may be caproic acid and / or a salt thereof, heptanoic acid and / or a salt thereof, caprylic acid and / or a salt thereof, pelargonic acid and / or a salt thereof, capric acid and / or a salt thereof, undecanoic acid and / or a salt thereof, lauric acid and / or a salt thereof, or any combination thereof, preferably chosen from Ce to Cio saturated straight-chain fatty acids and / or salts thereof. In another example, the at least one saturated straight-chain fatty acid and / or salt thereof comprises caproic acid and / or a salt thereof, caprylic acid and / or a salt thereof, capric acid and / or a salt thereof, lauric acid and / or a salt thereof, or any combination thereof, such as where at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or about 100%, by weight of the at least one saturated straight-chain fatty acid and / or salt thereof comprises caproic acid and / or a salt thereof, caprylic acid and / or a salt thereof, capric acid and / or a salt thereof, lauric acid and / or a salt thereof, or any combination thereof.

[0073] As used herein, the articles “a”, “an”, and “the” preceding an element or component of the invention are intended to be nonrestrictive regarding the number of instances (i.e., occurrences) of the element or component. Therefore “a”, “an”, and “the” should be read to include one or at least one, and the singular word form of the element or component also includes the plural unless the number is obviously meant to be singular.

[0074] As used herein, the term “comprising” means the presence of the stated features, integers, steps, or components and does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. That is, the stated features, integers, steps, or components may include other features, integers, steps, components or groups thereof. The term “comprising” is intended to include embodiments encompassed by the terms “consisting essentially of’ and “consisting of,” unless the context dictates otherwise.

[0075] The phrase “consisting of’ limits the scope to which the phrase applies to the stated elements, steps, or ingredients, precluding the inclusion of other elements or materials, except for impurities ordinarily associated therewith. For example, in the context of the fatty acids of the present disclosure, such impurities may include, for example, unsaturation, branching, and / or varying chain lengths above or below the stated ranges for chain-length.

[0076] The phrase “consisting essentially of’ limits the scope to which the phrase applies to the stated elements, steps, or ingredients and those that do not materially affect the basic and novel characteristic(s) of the claimed invention. “Consisting essentially of’ occupies a middle ground between a closed scope that is written in a “consisting of’ format and an open scope that is written in a “comprising” format.

[0077] As used herein, the term “about” modifying the quantity of an ingredient employed refers to variation in the numerical quantity that can occur, for example, through typical measuring and handling procedures used for making concentrates or use solutions in the real world; through inadvertent error in these procedures; through differences in the manufacture, source, or purity of the ingredients employed to make the compositions or carry out the methods; and the like.

[0078] Where present, all ranges are inclusive and combinable. For example, when a range of “1 to 5” is recited, the recited range should be construed as including ranges “1 to 4”, “1 to 3”, “1-2”, “1-2 & 4- 5”, “1-3 & 5”, and the like. When a parameter is given either as a range, preferred range, or a list of upper values and lower values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range.

[0079] EXAMPLES

[0080] Example 1

[0081] The preservative activity in representative rinse-off and leave-on formulations was evaluated using a modification of the Personal Care Products Council (PCPC - formerly the Cosmetic, Toiletry and Fragrance Association) protocol (Machtiger, et al. 2001. Determination of the Efficacy of Preservation of Non-Eye Area Water Miscible Cosmetic and Toiletry Formulations: Collaborative Study. J of AO AC International. 84: 1, 101-109).

[0082] This evaluation was conducted using a four week, two or three-cycle (i.e., two-cycle for personal care and three-cycle for home care applications) microbial preservative efficacy test (i.e., challenge test) at 25 °C to determine the preservative efficacy of each treatment. Phenoxyethanol, benzyl alcohol and the fatty acids identified below were tested alone and in various combinations. The fatty acids used in the testing were purchased from Sigma- Aldrich. The preservative and booster ingredients were dosed and mixed thoroughly at room temperature into various formulations, specifically different personal care formulations including a lotion (leave-on, Table 1), a micellar water (rinse-off, Table 2), and home care formulations including a manual dishwashing formulation (Table 3). In all cases after dosing, the pH of the final formulations were readjusted to match the pH of the original formulations prior to dosing, by using either citric acid, triethanolamine, or diluted sodium hydroxide.

[0083] Table 1 shows an exemplary formulation for carbomer-based lotion compositions. Carbomers are a commonly used synthetic rheological modifier in personal care products. The formulation below was made by heating the aqueous (A) and oil (B) phases separately to 75-80 °C. The oil phase was then poured into the aqueous phase and mixed by a homogenizer at approximately 45 °C. The formed oil- in-water emulsion was cooled to room temperature. Triethanolamine and / or diluted sodium hydroxide was used to adjust the final pH to 6.3, to 6.5 or to 7.5 (as indicated in the examples below).

[0084] Table 1. Representative Lotion Formulation with Carbomer

[0085] Table 2 shows a representative micellar water formulation. The micellar water composition was made by adding all the ingredients into a beaker and heating the ingredient mixture to 75-80 °C. The final product was cooled to room temperature and pH was adjusted to 6.0 or 7.5 (as indicated in the examples below), with citric acid solution and / or diluted sodium hydroxide. Table 2. Representative Micellar Water Composition

[0086] Table 3 shows a representative manual dishwashing formulation. The manual dishwashing formulation composition was made by adding all the ingredients into a beaker and heating the ingredient mixture to 60 °C. The final product was cooled to room temperature and pH was adjusted to 7.5 with citric acid solution and / or diluted sodium hydroxide (unless otherwise indicated in the examples below).

[0087] Table 3. Representative Manual Dishwashing Formulation

[0088] After dosing, the samples were divided into two separate five gram aliquots. One aliquot was inoculated with 50 pl of a diluted bacterial pool, and the second aliquot was inoculated with 50 pl of a diluted fungal pool as described below. Unpreserved product samples were included as a growth control.

[0089] A mixed bacterial inoculum was prepared using 24-hour cultures of the test bacteria (Table 4) grown in trypticase soy broth (TSB). Equal volumes of the bacterial test strains were combined and diluted one to ten in phosphate buffer to obtain an inoculum of approximately 5 x 107to 5 x 108colony forming units per ml (cfu / ml). The test samples were inoculated with 1% of the mixed bacterial inoculum. For both personal care and home care products, a mixed fungal inoculum was prepared using cell suspensions of the yeast Candida albicans ATCC # 10231 and the mold Aspergillus brasiliensis ATCC #16404 in phosphate buffer. Equal volumes of the fungal test strains were combined and diluted one to ten with phosphate buffer to obtain an inoculum of approximately 5 x 106to 5 x 107cfu / ml. The test samples were inoculated with 1% of the mixed fungal inoculum.

[0090] Table 4. Mixed Bacterial Inoculum for Personal Care and / or Home Care

[0091] For personal care products, the samples were subjected to two microbial challenges at time zero and inoculated a second time after seven days. For home care products, the samples were subjected to three microbial challenges at time zero and inoculated a second and third time after seven and fourteen days, respectively. The number of microorganisms added to each sample was determined by a standard Most Probable Number (MPN) determination in Trypticase Soy Broth (TSB) for bacteria and Potato Dextrose Broth (PDB) for fungi. Samples were incubated at 25 °C for the test duration of four weeks. Samples were monitored for bacterial and fungal contamination after 2, 7, 14, 21, and 28 days. Samples challenged with bacteria were streak -plated onto Trypticase Soy Agar (TSA) and incubated at 30 °C for 24 hours. Samples challenged with fungi were streak -plated onto Potato Dextrose Agar (PDA) and incubated at 25°C for 7 days. After incubation, plates were given a Growth Rating to determine the colony forming units per gram (CFU / g) present in each test sample at the testing time point. Table 5 represents the growth score.

[0092] Table 5. Growth score used to determine CFU / mL in test samples. A representative leave-on lotion formulation was made according to Table 1 (pH 6.3). As shown in Table 6, despite the pH of 6.3, the lotion formulations surprisingly showed significantly enhanced antimicrobial properties when benzyl alcohol was combined with the identified fatty acids (in many cases a 4 log growth reduction at Day 21 compared to dosing benzyl alcohol alone). Table 6. Challenge test data - lotion formulation comprising carbomer using benzyl alcohol (pH 6.3)

[0093] As shown in Table 7, despite the pH of 6.3, the lotion formulations also surprisingly showed significantly enhanced antimicrobial activity when phenoxyethanol was combined with the identified fatty acids (in many cases a >3 log growth reduction at Days 21 & 28 compared to dosing phenoxyethanol alone).

[0094] Table 7. Challenge test data - lotion formulation comprising carbomer using phenoxyethanol (pH 6.3)

[0095] Example 2

[0096] A representative micellar water formulation was made according to Table 2 (pH 7.5). As shown in

[0097] Table 8, despite the pH of 7.5, the micellar water formulations surprisingly showed significantly enhanced antimicrobial properties when benzyl alcohol was combined with the identified fatty acids (a > 3 log growth reduction at Day 28 against bacteria compared to dosing benzyl alcohol alone).

[0098] Table 8. Challenge test data - Micellar water formulation using benzyl alcohol (pH 7.5)

[0099] As shown in Table 9, despite the pH of 7.5, the micellar water formulations also surprisingly showed significantly enhanced antimicrobial properties when phenoxyethanol was combined with the identified fatty acids (a > 1 log growth reduction at Days 21 & 28 against bacteria compared to dosing phenoxyethanol alone; a > 1 log growth reduction at Days 21 & 28 against fungi compared to dosing phenoxyethanol alone).

[0100] Table 9. Challenge test data - Micellar water formulation using phenoxyethanol (pH 7.5) Example 3

[0101] A representative leave-on lotion formulation was made according to Table 1 (pH 7.5). As shown in Table 10, despite the pH of 7.5, the lotion formulations surprisingly showed significantly enhanced antimicrobial properties when benzyl alcohol was combined with the identified fatty acids (a > 3 log growth reduction at Day 28 against fungi compared to dosing benzyl alcohol alone). Table 10. Challenge test data - Lotion formulation with carbomer using benzyl alcohol (pH 7.5)

[0102] As shown in Table 11, despite the pH of 7.5, the lotion formulations also surprisingly showed significantly enhanced antimicrobial properties when phenoxyethanol was combined with the identified fatty acids (in most cases a > 2 log growth reduction at Days 21 & 28 against fungi compared to dosing phenoxyethanol alone).

[0103] Table 11. Challenge test data - Lotion formulation with carbomer using phenoxyethanol (pH 7.5)

[0104] Example 4

[0105] A series of preservative compositions with alkaline stabilizer were prepared according to Table 12. Phenoxyethanol and pelargonic acid were first mixed to form a homogenous clear solution. Sodium hydroxide (NaOH) or potassium hydroxide (KOH) was added to water to form an alkaline solution as the alkaline stabilizer. The alkaline solution was then slowly added to the homogenous clear solution.

[0106] The pH values of the final compositions were measured (Table 12).

[0107] Table 12, Preservative compositions with alkaline stabilizer All preservative compositions were stored in an oven at a temperature of 55 °C. Gas chromatography (GC) was used to measure the wt% loss of phenoxyethanol (POE) and pelargonic acid (PA) combined after 2 weeks and 5 weeks. As shown in Table 13, the addition of the alkaline solution stabilized the composition at elevated temperature over time (i.e., the compositions showed much lower wt% loss overtime). In particular, Samples 2 and 4 showed excellent shelf-life stability with less than 4.0 wt% loss of phenoxyethanol and pelargonic acid combined when stored at 55 °C for 5 weeks.

[0108] Table 13, Preservative composition stability with alkaline stabilizer

[0109] Example 5

[0110] A representative leave-on lotion formulation was made according to Table 1 (pH 6.5). As shown in Table 14, the preservative composition comprising phenoxyethanol (POE), pelargonic acid (PA) and an alkaline stabilizer which was an alkaline solution of potassium hydroxide (KOH + H2O) showed better efficacy against fungi compared to phenoxyethanol alone (the preservative composition also used 40% less POE compared to the sample dosed with POE alone). Further, as shown in Table 14, the preservative composition comprising POE, PA, the alkaline stabilizer and caprylhydroxamic acid (CHA) showed additional synergy and improvement at the same total dosing level (0.8%) compared to phenoxyethanol alone, even where the CHA load level was as low as 0.016% of the lotion formulation.

[0111] Table 14. Challenge test data - lotion formulation

[0112] A representative manual dishwash formulation was made according to Table 15 (pH 6.5). The dishwash formulation was dosed with phenoxyethanol (POE) alone at a load level of 0.8 wt% and, separately, the dishwash formulation was dosed with the same preservative compositions as shown in Table 14 above, each at a total load level of 0.8 wt%. As shown in Table 15 , the preservative compositions of the present disclosure showed significantly better efficacy against fungi compared to phenoxyethanol alone (e.g., >2 log reduction improvement at days 21 and 28).

[0113] Table 15. Challenge test data - Manual dishwash formulation

[0114] Example 6 A representative micellar water formulation was made according to Table 2 (pH 6.0). As shown in Table 16, when benzyl alcohol was combined with the identified fatty acids, the preservative activity was surprisingly enhanced, particularly against fungi (i.e., >2 log reduction against fungi at day 21 compared to benzyl alcohol alone). When phenoxyethanol was combined with the identified fatty acids, the preservative activity was surprisingly enhanced in particular for the combinations with caproic acid (Ce), caprylic acid (Cs), and pelargonic acid (C>), respectively (i.e., a 2 log reduction against bacteria at day 21 compared to phenoxyethanol alone).

[0115] Table 16. Challenge test data - Micellar water formulation using phenoxyethanol (pH 6.0)

Claims

What is claimed is:

1. A stabilized antimicrobial composition comprising(a) an antimicrobial agent selected from the group consisting of phenoxyethanol, benzyl alcohol and combinations thereof,(b) at least one saturated straight-chain fatty acid having a carbon chain length of from six to twelve carbon atoms and / or a salt thereof, and(c) at least one alkaline stabilizer, wherein the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid (b) are present in a combined amount of from about 50 wt% to about 99.8 wt%, based on the total weight of the composition, the antimicrobial composition has a pH from about 5.0 to about 7.5, and the ratio by weight of the antimicrobial agent (a) to the at least one saturated straight-chain fatty acid and / or salt thereof (b) is from about 20: 1 to about 1:2.5.

2. The antimicrobial composition of claim 1, wherein the at least one saturated straight-chain fatty acid and / or salt thereof comprises caproic acid and / or a salt thereof, caprylic acid and / or a salt thereof, capric acid and / or a salt thereof, lauric acid and / or a salt thereof, or any combination thereof.

3. The antimicrobial composition of claim 1 or 2, wherein the antimicrobial agent (a) is phenoxyethanol.

4. The antimicrobial composition of claim 1 or 2, wherein the antimicrobial agent (a) is benzyl alcohol.

5. The antimicrobial composition of any one of claims 1 -4, wherein the component (b) is a mixture of two or more of said saturated straight-chain fatty acids and / or salts thereof.

6. The antimicrobial composition of any preceding claim, wherein the at least one alkaline stabilizer comprises a base chosen from a metal hydroxide, oxide, carbonate, bicarbonate, phosphate, or hydride, an amine base or a combination thereof.

7. The antimicrobial composition of claim 6, wherein the base is chosen from sodium hydroxide, potassium hydroxide or a combination thereof.

8. The antimicrobial composition of any preceding claim, wherein the alkaline stabilizer constitutes from about 3 wt% to about 15 wt%, based on the total weight of the composition.

9. The antimicrobial composition of any preceding claim, wherein the composition exhibits < 5 wt% loss of the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) combined when stored at 55° C for two weeks.

10. The antimicrobial composition of any preceding claim, wherein the composition exhibits < 10 wt% loss of the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) combined when stored at 55° C for five weeks.

11. The antimicrobial composition of any preceding claim, wherein the antimicrobial composition comprises the components (a) and (b) in a combined amount of at least 75 wt%, based on the total weight of the antimicrobial composition.

12. The antimicrobial composition of any preceding claim, wherein the antimicrobial composition further comprises (d) one or more than one additional antimicrobial agent.

13. The antimicrobial composition of claim 12, wherein the ratio by weight of the combined amount of (a) and (b) to the amount of (d) ranges from about 5: 1 to about 150: 1.

14. The antimicrobial composition of claim 12 or 13, wherein the antimicrobial composition comprises the one or more than one additional antimicrobial agent (d) in an amount no greater than 10 wt%, based on the total weight of the antimicrobial composition.

15. The antimicrobial composition of claim 12, wherein the ratio by weight of the combined amount of (a) and (b) to the amount of (d) ranges from about 12: 1 to about 100: 1.

16. The antimicrobial composition of claim 12 or 15, wherein the antimicrobial composition comprises the one or more than one additional antimicrobial agent (d) in an amount no greater than 5 wt%, based on the total weight of the antimicrobial composition.

17. The antimicrobial composition of any one of claims 12-16, wherein the one or more than one additional antimicrobial agent (d) comprises an alkylhydroxamic acid and / or salt thereof.

18. The antimicrobial composition of claim 17, wherein the alkylhydroxamic acid and / or salt thereof is caprylhydroxamic acid and / or a salt thereof.

19. The antimicrobial composition of any preceding claim, wherein the ratio by weight of the component (a) to the component (b) is from about 5: 1 to about 1: 1.5.

20. An aqueous product formulation comprising an antimicrobial effective amount of the antimicrobial composition according to any preceding claim.

21. The aqueous product formulation of claim 20, wherein the formulation is in the form of a personal care or home care formulation.

22. The aqueous product formulation of claim 20 or 21, wherein the formulation has a pH of at least 6.0.

23. The aqueous product formulation of claim 20 or 21, wherein the formulation has a pH of at least 6.5.

24. The aqueous product formulation of claim 20 or 21, wherein the formulation has a pH of at least 7.0.

25. The aqueous product formulation of claim 20 or 21, wherein the formulation has a pH of at least 7.5.

26. A personal care or home care product formulation comprising an antimicrobial effective amount of a combination of (a) an antimicrobial agent selected from the group consisting of phenoxyethanol, benzyl alcohol and combinations thereof, and (b) at least one saturated straight-chain fatty acid having a carbon chain length of from six to twelve carbon atoms and / or a salt thereof, and one or more additional ingredients suitable for use in a personal care or home care product formulation,wherein the ratio by weight of the antimicrobial agent (a) to the at least one saturated straightchain fatty acid and / or salt thereof (b) is from about 40: 1 to about 1:5, and wherein the product formulation has a pH of at least 6.0.

27. A method of controlling microbial growth in or preserving a product formulation, comprising adding to the product formulation (a) an antimicrobial agent selected from the group consisting of phenoxyethanol, benzyl alcohol and combinations thereof, and (b) at least one saturated straight-chain fatty acid having a carbon chain length of from six to twelve carbon atoms and / or a salt thereof, wherein the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) are present in the formulation in a combined antimicrobial effective amount, the ratio by weight of the antimicrobial agent (a) to the at least one fatty acid and / or salt thereof (b) is from about 40: 1 to about 1:5, and the product formulation has a pH of at least 6.0.

28. The product formulation or method of claim 26 or 27, wherein the at least one saturated straight-chain fatty acid and / or salt thereof comprises caproic acid and / or a salt thereof, caprylic acid and / or a salt thereof, capric acid and / or a salt thereof, lauric acid and / or a salt thereof, or any combination thereof.

29. The product formulation or method of any one of claims 26-28, wherein the ratio by weight of the antimicrobial agent (a) to the at least one saturated straight-chain fatty acid and / or salt thereof (b) is from about 20: 1 to about 1:2.5.

30. The product formulation or method of claim 29, wherein the ratio by weight of the antimicrobial agent (a) to the at least one saturated straight-chain fatty acid and / or salt thereof (b) is from about 10: 1 to about 1: 1.5.

31. The product formulation or method of any one of claims 26-30, wherein the antimicrobial effective amount of the combination of the antimicrobial agent (a) and the at least one saturated straight-chain fatty acid and / or salt thereof (b) is from about 0.2 to about 3 wt%, based on the total weight of the formulation.

32. The product formulation of claim 31, further comprising (c) an alkylhydroxamic acid and / or a salt thereof, wherein the ratio by weight of the combined amount of (a) and (b) to the amount of (c) is from about 5: 1 to about 150: 1.

33. The method of claim 31, further comprising adding to the product formulation (c) an alkylhydroxamic acid and / or a salt thereof, wherein the ratio by weight of the combined amount of (a) and (b) to the amount of (c) is from about 5: 1 to about 150: 1.

34. The product formulation or method of claim 32 or 33, wherein the ratio by weight of the combined amount of (a) and (b) to the amount of (c) is from about 12: 1 to about 100: 1.

35. The product formulation or method of any one of claims 32-34, wherein the alkylhydroxamic acid and / or salt thereof (c) is present in the formulation in an amount no greater than 0. 1 wt%, based on the total weight of the formulation.

36. The product formulation or method of any one of claims 32-35, wherein the alkylhydroxamic acid and / or salt thereof is caprylhydroxamic acid and / or a salt thereof.

37. The product formulation or method of any one of claims 26-36, wherein the formulation has a pH of at least 6.5.

38. The product formulation or method of any one of claims 26-36, wherein the formulation has a pH of at least 7.0.

39. The product formulation or method of any one of claims 26-36, wherein the formulation has a pH of at least 7.5.

40. Use of at least one fatty acid having a carbon chain length of from six to twelve carbon atoms and / or a salt thereof to enhance the antimicrobial efficacy of an antimicrobial agent selected from the group consisting of phenoxyethanol, benzyl alcohol and combinations thereof in a product formulation having a pH of at least 6.0.

41. The use of claim 40, wherein the at least one saturated straight-chain fatty acid and / or salt thereof comprises caproic acid and / or a salt thereof, caprylic acid and / or a salt thereof, capric acid and / or a salt thereof, lauric acid and / or a salt thereof, or any combination thereof.

42. The use of claim 40 or 41, wherein the pH of the product formulation is at least 6.5.

43. The use of claim 40 or 41, wherein the pH of the product formulation is at least 7.0.

44. The use of claim 40 or 41, wherein the pH of the product formulation is at least 7.5.

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