Potentiated antimicrobial composition for the antimicrobial treatment of biofilms

Abstract

The invention relates to the use of a composition for the antimicrobial and/or antioxidative treatment of biofilms in water-containing liquids, comprising: (a) a micelle-forming solubilizate which comprises at least one plant extract, at least one emulsifier with an HLB number of 8 to 18, and water, and (b) at least one biodegradable antimicrobial agent selected from the group consisting of peroxides, including peroxycarboxylic acids and H.sub.2O.sub.2, hypochlorites, hypochlorous acid and a combination thereof.

Claims

1. A method for an antimicrobial and/or antioxidative treatment of biofilms in an aqueous liquid, the method comprising: introducing into the aqueous liquid a composition which comprises: (a) a micelle forming solubilizate which comprises 5 to 40% by weight of at least one plant extract, 30 to 85% by weight of at least one emulsifier with an HLB value of 8 to 18, and water, and (b) 13 to 19% by weight H.sub.2O.sub.2 and 1 to 2.5% by weight L(+) lactic acid, wherein the aqueous liquid is not a human or animal body fluid.

2. The method of claim 1, wherein the at least one emulsifier comprises at least 80% by weight of polysorbates.

3. The method of claim 1, wherein the at least one plant extract is selected from the group consisting of extracts of spice plants or parts thereof, extracts of citrus plants or parts thereof, and combinations of these extracts.

4. The method of claim 3, wherein the at least one plant extract originates from olives, garlic, onions and/or citrus fruits.

5. The method of claim 1, wherein the micelles have a mean diameter of from 1 to 100 nm.

6. The method of claim 1, wherein the aqueous liquid is selected from the group consisting of process water, wastewater, surface water, and fill-up water.

7. The method of claim 6, wherein the process water is water in technical, medical technology, industrial or commercial installations.

8. The method of claim 6, wherein the process water is present as cooling water in a cooling water system or is treated for use in a cooling water system.

9. The method of claim 6, wherein the process water is present in water-conducting elements of beer brewing installations, circulating coolers and/or draft dispensers or is treated for use in beer brewing installations, circulating coolers and/or draft dispensers.

10. The method of claim 6, wherein the process water is present in water-conducting elements of medical technology installations or is treated for use in medical technology installations.

11. The method of claim 6, wherein the fill-up water is fill-up water for water basins, water tanks, domestic water conduits and hot water circuits.

12. The method of claim 1, wherein the composition is introduced in an amount effective to combat and prevent the growth of gram-positive and gram-negative bacteria, fungi and/or protozoa, which occur in biofilms in aqueous liquids.

13. The method of claim 12, wherein the composition is introduced into a water-conducting conduit containing the biofilm.

14. A composition for an antimicrobial and/or antioxidative treatment of biofilms in aqueous liquids, comprising: (a) 78.5% to 86% by weight of a micelle-forming solubilizate which comprises 5 to 40% by weight of at least one plant extract, wherein the at least one plant extract originates from olives, garlic, onions and/or citrus fruits, 30 to 85% by weight of at least one emulsifier, wherein the at least one emulsifier comprises at least 80% by weight of polysorbates, and 10 to 40% by weight of water, and (b) 13 to 19% by weight H.sub.2O.sub.2 and 1 to 2.5% by weight L(+) lactic acid.

15. The composition of claim 14, wherein the micelles have a mean diameter of from 1 to 100 nm.

16. The method of claim 1, wherein the micelles have a mean diameter of from 3 to 50 nm.

17. The method of claim 1, wherein the micelles have a mean diameter of from 5 to 20 nm.

18. The composition of claim 14, wherein the micelles have a mean diameter of from 3 to 50 nm.

19. The composition of claim 14, wherein the micelles have a mean diameter of from 5 to 20 nm.

20. The method of claim 6, wherein the process water is present as cooling water in a cooling water system for cooling towers, or is treated for use in a cooling water system for cooling towers.

21. The method of claim 12, wherein the composition is introduced into a water-conducting conduit containing the biofilm, wherein the water-conducting conduit is a cooling water conduit.

22. The method of claim 1, wherein the emulsifier comprises at least 80% by weight of polyoxyethylene (20) sorbitan monolaurate (polysorbate 20) and/or polyoxyethylene (20) sorbitan monooleate (polysorbate 80).

23. The composition of claim 14, wherein the emulsifier comprises at polyoxyethylene (20) sorbitan monolaurate (polysorbate 20) and/or polyoxyethylene (20) sorbitan monooleate (polysorbate 80).

Description

EXAMPLE 1: PRODUCTION OF AN ANTIMICROBIAL COMPOSITION USING A MICELLE-FORMING SOLUBILIZATE

(1) ProExtrakt P150 from the company Procena GmbH, Germany, which contains a mixture of plant extracts from olives, garlic, onions and citrus fruits as well as glycerol (E 422) and vitamin C (ascorbic acid, E 300), was used as plant extract. It is known that olives, garlic, onions and citrus fruits contain substances that, besides antioxidant properties, also possess antimicrobial activity directed against bacteria, yeasts and fungi. Known active substances are for example oleuropein in olives and allicin in garlic.

(2) For the production of the antimicrobial potentiated composition according to the invention, 30% by weight of ProExtrakt P150 were mixed with 35% by weight of water at about 45 to 50° C., and this mixture was stirred into 35% by weight of the emulsifier polysorbate 80 (Novasol Item No. EW0240/2, Aquanova AG, 64295 Darmstadt, DE; E number: E 433) heated to about 50° C. The preparation obtained was subsequently heated to about 90° C. and homogenized until the desired oil- and water-soluble micelle-forming solubilizate was obtained. Subsequently, in this example, the biodegradable antimicrobial active substance H.sub.2O.sub.2 (hydrogen peroxide; IBEN Mikro Stop GmbH, 27572 Bremerhaven, DE) in an amount of 15 to 19 vol. % and, for additional active substance enhancement, additionally L(+) lactic acid (IBEN Mikro Stop GmbH, 27572 Bremerhaven, DE) in an amount of 2 to 2.5 vol. %, and optionally additional water were added, wherein a antimicrobial composition with potentiated efficiency for use in the present invention was obtained, which can be used for the treatment of water by introduction into or application to water, such as, nut not exclusively, drinking water, wastewater, process water, or surface water. The micelles which are contained in the composition obtained by this method have a size of about 3-50 nm, preferably 5-20 nm. Under the above-described conditions, micelles in the specified size ranges form automatically, wherein the sizes of the micelles can be readily set or optimized by a person skilled in the art.

EXAMPLE 2—ANTIMICROBIAL EFFICACY OF THE ANTIMICROBIAL COMPOSITION USED IN ACCORDANCE WITH THE INVENTION IN SIMULATED COOLING WATER

(3) Sample solutions of 0.1% by weight, 0.25% by weight, 0.5% by weight, 1% by weight, 2.5% by weight, 5% by weight, and 10% by weight of the composition described in Example 1 were examined in accredited microbiological laboratories in Germany in accordance with DIN EN 13623:2010 in comparison to water of standardized hardness (WSH) as control, an aqueous 7.5% H.sub.2O.sub.2 (hydrogen peroxide; 50% solution of a 15 vol. % H.sub.2O.sub.2 stock solution in water) as control, an aqueous 1% polysorbate 80 solution as control, a 20% aqueous plant extract solution as control, and a 20% aqueous solution of the functionalized plant extract (micelle-forming solubilizate) as control against the biofilm-forming bacterium Legionella pneumophilia (ATCC 33152) in an aqueous environment at pH 8.0 with addition of 0.005% yeast extract for simulating cooling water with exposure times of 15 min, 30 min, 60 min and 120 min.

(4) The measurement results of the antimicrobial effect of WSH, an aqueous 7.5% H.sub.2O.sub.2 solution alone, the plant extract ProExtrakt P150 alone, the emulsifier polysorbate 80 alone, the functionalized plant extract (micelle-forming solubilizate) alone and different dilutions of the composition according to the invention are shown below in Table 1.

(5) TABLE-US-00001 TABLE 1 Potentiated antimicrobial effectiveness of a composition according to the invention (H.sub.2O.sub.2 and L(+) lactic acid in aqueous medium in combination with a micelle-forming solubilizate): Test Substance Function 15 min 30 min 60 min 120 min WSH Control 0.07 0.08 0.08 0.10 7.50% H.sub.2O.sub.2 Control 2.24 3.44 4.25 4.83 1% PSb 80 Control 0.06 0.09 0.09 0.11 20% PE Control 0.76 0.92 1.24 1.27 20% fPE Control 0.80 0.95 1.30 1.25 10.00% PAM Intervention >5.56 >5.56 >5.56 >5.56 5.00% PAM Intervention >5.56 >5.56 >5.56 >5.56 2.50% PAM Intervention >5.56 >5.56 >5.56 >5.56 1.00% PAM Intervention >5.55 >5.56 >5.56 >5.56 0.50% PAM Intervention 4.56 <5.55 <5.55 n.p. 0.25% PAM Intervention <3.18 <5.55 <5.55 n.p. 0.10% PAM Intervention <2.88 <2.88 <2.88 n.p.

(6) Results presented as Log.sub.10) reduction factor in relation to L. pneumophilia (ATCC 33152); n.p.=not performed; WSH=water of standardised hardness; PSb 80=polysorbate 80; PE=phytoextract (P150); fPE=functionalised phytoextract (=micelle-forming solubilizate); PAM=Potentiated antimicrobial mixture

(7) The results clearly show that, compared to WSH, which as expected did not demonstrate an antimicrobial effect, the antimicrobial effect of H.sub.2O.sub.2 is increased by packaging in micelles formed from functionalised phytoextracts and lactic acid as compared to H.sub.2O.sub.2 alone or as compared to the controls. This phenomenon is also effective against the bacterium L. pneumophilia in cooling water, as is used for example in industrial cooling towers, said bacterium occurring in water and forming a biofilm.

(8) The results of the tests show that, by application of a potentiated antimicrobial active substance or active substance mixture by means of micelle-forming solubilizates based on plant extract/emulsifier, the application concentrations and/or exposure times of existing known antimicrobial substances in water for the purposes of antimicrobial treatment of water can be reduced by introduction into, or application to water, for example, but not exclusively, drinking water, wastewater, process water or surface water.

(9) The results additionally show that even all dilution stages of the composition according to the invention have an improved effect against L. pneumophilia in simulated cooling water, for the majority of all tested concentrations and exposure times. In the examined samples the corresponding non-micellated antimicrobial test sample by contrast did not demonstrate an improved effect in relation to the micellated test sample.

EXAMPLE 3—ANTIMICROBIAL EFFICACY OF THE ANTIMICROBIAL COMPOSITION USED IN ACCORDANCE WITH THE INVENTION IN BIOFILM

(10) In order to determine the antimicrobial efficacy of the potentiated antimicrobial active substance or active substance mixture by means of micelle-forming solubilizates based on plant extract/emulsifier in relation to bacteria in biofilm, the effect of water of standardised hardness (WSH), an aqueous 17% H.sub.2O.sub.2 solution, and a 1.7% H.sub.2O.sub.2 solution (1:10) alone, the plant extract ProExtrakt P150 in a 0.3% dilution alone, 2% lactic acid alone, and an undiluted and a 1:10 diluted solution of the antimicrobial composition described above in Example 1 and in Example 2 and used in accordance with the invention was examined. The results are shown below in Table 2.

(11) TABLE-US-00002 TABLE 2 Potentiated antimicrobial effectiveness of a composition used in accordance with the invention (H.sub.2O.sub.2 and L(+) lactic acid in aqueous medium in combination with a micelle- forming solubilizate; for production see Example 1) in relation to P. aeruginosa in biofilm (starting number: > 8 log.sub.10 cfu/cm.sup.2): Test Substance Function 5 min 15 min 30 min 60 min WSH Control 0.03 0.06 0.05 0.07 1.7% H.sub.2O.sub.2 Control 0.84 1.62 1.95 2.53 17% H.sub.2O.sub.2 Control >8.00 >8.00 >8.00 >8.00 0.3% fPE Control 0.64 0.56 0.73 0.78 2% MS Control 3.45 3.85 4.25 4.40 100% PAM Intervention >8.00 >8.00 >8.00 >8.00 10.00% PAM Intervention 7.85 >8.00 >8.00 >8.00

(12) Results presented as Log.sub.10) reduction factor in relation to P. aeruginosa (PA01); WSH=water of standardised hardness; fPE=functionalised phytoextract (=micelle-forming solubilizate); MS=L(+) lactic acid; PAM=Potentiated antimicrobial mixture according to the invention.

(13) The results show that, in comparison to WSH, which as expected did not demonstrate an antimicrobial effect in relation to P. aeruginosa in biofilm 24 hours old, both a 17% H.sub.2O.sub.2 solution and an undiluted solution of 17% H.sub.2O.sub.2 demonstrate, after just 5 minutes of exposure time, a high antimicrobial effect in relation to the test organisms in biofilms 24 hours old by packaging in micelles formed from functionalised phytoextracts (=100% PAM) and lactic acid.

(14) The individual constituents 0.3% fPE and 2% MS themselves had no antimicrobial effect in relation to the test organisms in biofilms.

(15) With a 1:10 dilution of 17% H.sub.2O.sub.2 (=1.7% H.sub.2O.sub.2) or a 1:10 dilution of 17% H.sub.2O.sub.2 by means of packaging in micelles formed from functionalised phytoextracts and lactic acid (=10% PAM), an antimicrobial difference of more than 5.47 to 7.01 log.sub.10 cfu reduction was visible within 5 to 60 minutes of exposure time with application of 1.7% H.sub.2O.sub.2 by packaging in micelles formed from functionalised phytoextracts and lactic acid (=10% PAM), which demonstrated an antimicrobial potentiation.

(16) To summarise, the results show that the antimicrobial efficacy of 17% H.sub.2O.sub.2 and of 100% PAM (containing 17% H.sub.2O.sub.2) in relation to biofilms is considered to be high and substantially equivalent. The antimicrobial effect of this high concentration of H.sub.2O.sub.2 is not surprising per se.

(17) The results with a much lower concentrated hydrogen peroxide solution, specifically 1.7% H.sub.2O.sub.2, demonstrated a significant loss of antimicrobial efficacy in biofilms compared to 17% H.sub.2O.sub.2 and 100% PAM. Surprisingly, however, a high antimicrobial efficacy in biofilms, comparable to that of highly dosed 17% H.sub.2O.sub.2 or 100% PAM, was determined for the diluted 10% PAM (containing 1.7% H.sub.2O.sub.2). With an already low concentration of the composition according to the invention (see result for 10% PAM), a high antimicrobial efficacy in relation to biofilms is thus achieved, which at the same time entails ecological and economical advantages and in practical use poses a very low risk potential for the user.

LITERATURE

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