AQUEOUS FOAMING COMPOSITION AND USE THEREOF FOR THE PREVENTION AND/OR INHIBITION OF AEROSOL FORMATION FROM THE REBOUND OF A LIQUID ON A SURFACE

Abstract

An aqueous foaming composition effective in preventing and/or inhibiting formation of aerosols from the rebound of a liquid on a surface, particularly from the rebound of urine on an external and/or internal surface of a toilet is provided. The aqueous foaming composition comprises at least one betaine, at least one anionic surfactant, at least one dialkyl carbonate, at least one fatty alcohol with a linear or branched, saturated or unsaturated alkyl chain containing at least 4 carbon atoms, at least one fatty acid ester with a linear or branched, saturated or unsaturated alkyl chain containing at least 4 carbon atoms and, optionally, at least one pH regulator, at least one deodorizing substance and/or a propellant gas.

Claims

1. An aqueous foaming composition comprising at least one betaine, at least one anionic surfactant, at least one dialkyl carbonate, at least one fatty alcohol with a linear or branched, saturated or unsaturated alkyl chain containing at least 4 carbon atoms, and at least one fatty acid ester with a linear or branched, saturated or unsaturated alkyl chain containing at least 4 carbon atoms.

2. The aqueous foaming composition of claim 1, wherein the at least one betaine is selected from the group consisting of alkylbetaines, alkylamidobetaines, sulfobetaines, and any mixture thereof.

3. The aqueous foaming composition of claim 1, wherein the at least one anionic surfactant is selected from the group consisting of sulfonate surfactants, alkyl sulfates, alkyl ether sulfates, alkyl aryl sulfates and any mixture thereof.

4. The aqueous foaming composition of claims 1, wherein the at least one dialkyl carbonate is bis-propylheptyl carbonate.

5. The aqueous foaming composition of claim 1, wherein the at least one fatty alcohol is selected from the group consisting of cetyl alcohol, stearyl alcohol and any mixture thereof.

6. The aqueous foaming composition of claim 1, wherein the at least one fatty acid ester is selected from the group consisting of isopropyl myristate, cetearyl myristate, and any mixture thereof.

7. The aqueous foaming composition of claim 1, further comprising a pH regulator, at least one deodorizing substance and/or a propellant gas.

8. The aqueous foaming composition of claim 7, wherein the pH regulator is an organic acid.

9. (canceled)

10. The aqueous foaming composition of claim 7, wherein the at least one deodorizing substance is selected from the group consisting of triethyl citrate, essence of bergamot, antibacterial agents, ricinoleate, and any mixture thereof.

11. (canceled)

12. The aqueous foaming composition of claim 7, wherein the propellant gas is selected from the group consisting of liquefied petroleum gas (LPG), hydrofluoroalkanes, hydrocarbons and nitrogen protoxide.

13. A method for preventing and/or inhibiting formation of aerosols from rebound of a liquid on a surface, the method comprising coating said surface with the aqueous foaming composition of claim 1.

14. The method of claim 13, wherein the surface is coated by spraying the aqueous foaming composition onto said surface.

15. The method of claim 13, wherein the liquid is animal urine.

16. The method of claim 15, wherein the animal urine is human urine, and the surface is an external surface and/or an internal surface of a toilet bowl.

17. Use of the aqueous foaming composition of claim 1, for preventing and/or inhibiting formation of aerosols from rebound of liquid on a surface.

18. (canceled)

19. (canceled)

20. The aqueous foaming composition of claim 1, wherein the at least one betaine is present in the composition in a total amount ranging from 2% to 5% by weight of the total weight of the composition.

21. The aqueous foaming composition of claim 1, wherein the at least one anionic surfactant is present in the composition in a total amount ranging from 0.3% to 3% by weight of the total weight of the composition.

22. The aqueous foaming composition of claim 1, wherein the at least one dialkyl carbonate is present in the composition in a total amount ranging from 0.5% to 3.5% by weight of the total weight of the composition.

23. The aqueous foaming composition of claim 1, wherein the at least one fatty alcohol is present in the composition in a total amount ranging from 0.5% to 2.5% by weight of the total weight of the composition.

24. The aqueous foaming composition of claim 1, wherein the at least one fatty acid ester is present in the composition in a total amount ranging from 0.1% to 3% by weight of the total weight of the composition.

Description

[0071] The experimental part which follows is provided for illustrative and non-limiting purposes of the scope of the invention as defined in the appended claims. In the experimental part reference is made to the appended drawings, wherein:

[0072] FIG. 1 shows a schematic representation of the system used for the experiments comprising (1) a toilet, (2) a toilet seat on which the blotting paper is placed to perform the tests and (3) a device to simulate urination. At the top is shown the camera (4) used to collect the images;

[0073] FIG. 2 shows the rebound aerosol formed and collected on the blotting paper of the toilet seat in the absence (A) and in the presence (C) of the foaming composition of the invention. The blotting paper was divided into four quadrants; the images in (B) and (D) are, respectively, an enlargement of the upper left panel of the blotting paper shown in (A) and (C);

[0074] FIG. 3 shows a schematic reproduction of the toilet seat cover, with the six Petri dishes numbered 1 to 6 (in bold). For each dish a numerical interval is reported in brackets indicating the number of recovered bacterial colonies, expressed in CFU, that were observed in the three replicates, in the condition in which the foaming composition of the invention was not used;

[0075] FIG. 4 shows a graph indicating the average values and standard deviation of the number of colonies collected in the three Petri dish replicates, expressed as CFU/cm.sup.2, in the presence of the foaming composition of the invention (triangle), and in its absence (square).

EXAMPLE 1

Experimental Model

[0076] The experimental model set up by the inventors is illustrated in its main components in FIG. 1. The toilet bowl 1 was made of Lexan, a resin belonging to the polycarbonate family, since this material is transparent, has a regular surface, and may be easily cut and bent. The toilet bowl thus created allows both the inclination of the walls and the level of the water at the bottom to be adjusted. The surface of the toilet seat 2 is made up of a square of one meter on each side on which the blotting paper is placed to perform the test.

[0077] The device 3 used to simulate urination is adjustable in height, position, and inclination. The flow rate is adjustable for both the flow (ml/min) and the total volume of the urine. For their experiments, the inventors chose the reference parameters of an adult man, that is, 20 ml/s for 20 s.

[0078] The liquid used by the inventors was water kept at a temperature of 37° C. in order to have the same surface tension as urine and colored with methylene blue so that the secondary aerosol could leave a visible trace on the blotting paper.

[0079] Since the secondary droplets (secondary aerosol) obtained through experimentation, i.e., from the stream of colored water at 37° C. on the surface of the toilet, have on average dimensions less than one millimeter in diameter, in order to analyze the data thoroughly qualitatively and quantitatively, it was necessary to take photos of the droplets at close range, parallel to the film plane. By virtue of these considerations, the paper quadrant lying on the toilet seat (70×70 cm) was divided into 4 quadrants, each 35×35 cm in size (FIGS. 2A-D).

[0080] As illustrated in FIG. 1, in the experiments of the present invention, a camera 4, in particular a Nikon D800 camera, was used with the aid of a tripod. For the analysis of the images, “Image J,” a computer program for processing digital images, was used. The characteristic values of hue, saturation, and brightness were standardized and used for all experiments.

EXAMPLE 2

Effectiveness of the Foaming Composition of the Invention

[0081] In the experiments conducted by the inventors, the traces of secondary droplets (secondary aerosol) caused by the stream of colored water at 37° C. on the surface of the toilet and released on the blotting paper are calculated as the number of blue points occupying a certain surface (for example 1386 drops, area of 1.71%). A typical result obtained from an experiment conducted in the absence of the foaming composition of the invention is shown in FIGS. 2A-B. Furthermore, by evaluating the color intensity of the individual points, by means of a preliminary calibration process, the inventors traced the overall volume of dispersed fluid. The analysis of the various samples was carried out by means of an automated image analysis, the results of which are shown in FIGS. 2B and D.

[0082] The effectiveness of the foaming composition of the invention in preventing and/or inhibiting the formation of secondary aerosol is clearly indicated in FIGS. 2C-D, which show a sample of blotting paper resulting from an experimental test conducted as previously described but in the presence of the foaming composition on the walls of the toilet. Unlike the result of the experiment carried out in the absence of the composition of the invention (shown in FIGS. 2A-B), no droplet is present on the blotting paper sample of FIGS. 2C-D, equal to 0% of occupied surface. This result demonstrates the capability of the aqueous foaming composition of this invention to prevent and/or inhibit the formation of aerosols from the rebound of a liquid on a surface.

EXAMPLE 3

Stability of the Foaming Composition of the Invention

[0083] Of particular importance for the purposes of the function that the foaming composition of the invention must perform is its stability over time, since a formulation that dissolves rapidly will not prevent the formation of aerosols during the entire urination, whereas, conversely, a foam that is too stable is difficult to remove or requires too much water to clean the toilet bowl. Although urination has been reported to have an average duration of around 21 seconds (Yang P. et al. PNAS 2014, vol. 111; no. 33 p. 11932-11937), the act of urination itself may vary greatly due to of the variability of individuals (age, pathologies, behavioral habits) and therefore the inventors tested the stability of the foaming composition for up to 2 (two) minutes from the deposition, obtaining results comparable to those shown in the preceding paragraph.

[0084] For comparison, the inventors tried various commercially available foams obtained both from soaps and liquid or powder detergents and directly from pressurized cylinders, for example shaving foams. In none of the tested samples was found an adequate characteristic of stability, consistency, and adhesion to the toilet wall that was suitable to prevent and/or inhibit the formation of aerosols from rebound streams of urine.

EXAMPLE 4

Antimicrobial Efficacy of the Foaming Composition of the Invention

[0085] The inventors conducted a study aimed at demonstrating that the foaming composition of the invention exerts an antimicrobial activity preventing, during urination, the formation of rebound droplets, potential carriers of pathogenic microorganisms.

[0086] For the experiments, the inventors employed a device comprising:

[0087] 1) a ceramic toilet bowl;

[0088] 2) a system for the stream of liquid simulating urination, consisting of a beaker (positioned 2 meters above the floor) containing 500 ml of saline solution and a silicone tube with a diameter of 0.4 cm with a tap for the flow;

[0089] 3) a toilet lid, with central slot, made of cardboard, with six lidless Petri dishes containing MacConckey agar (total surface 381 cm.sup.2), fixed on the internal surface of the toilet lid to recover any bacterial cells that may have volatilized during the dispensing of the liquid stream (FIG. 3).

[0090] At the start of the process and at the end of each experiment, all surfaces were thoroughly cleansed with 70% ethyl alcohol.

[0091] A multi-resistant bacterial isolate (MDR) of Klebsiella pneumoniae (KPO4_2019_UNIFG), obtained in 2019 from blood cultures of a patient with sepsis, was used as the pathogen.

[0092] KPO4_2019_UNIFG cells were cultured in LB agar plates aerobically at 35±2° C. overnight. The bacterial colonies grown on the plates were then suspended in saline solution to reach 0.5 McFarland standard (MF), corresponding to approximately 1×10.sup.8 CFU/ml. The suspension was then diluted in 2 liters of saline solution to reach a final bacterial load of 1×10.sup.5 CFU/ml.

[0093] The experiments were performed under three different conditions (in triplicate):

[0094] a) 2 liters of saline solution (negative control) were poured into the toilet and followed by a stream of liquid made with 500 ml saline solution, poured for 30 seconds;

[0095] b) 2 liters of bacterial suspension containing 1×10.sup.5 CFU/ml of the bacterial isolate in saline solution, used to uniformly contaminate the internal surfaces of the toilet bowl and to fill the bottom, followed by a stream of liquid made with 500 ml of saline solution, poured for 30 seconds;

[0096] c) 2 liters of bacterial suspension containing 1×10.sup.5 CFU/ml of the bacterial isolate in saline solution, used to uniformly contaminate the internal surfaces of the toilet bowl and to fill the bottom, followed by a layer of foam deposited on the internal walls of the toilet bowl before adding the liquid stream, followed by a liquid stream made up of 500 ml saline solution, poured in for 30 seconds.

[0097] After delivery of the stream, the MacConckey agar plates used in each experiment were incubated in ambient air at 35±2° C. for 12-18 hours. The detected microbial load was expressed in recovered CFU/cm.sup.2. The recovered colonies were identified at the species level by MALDI-TOF mass spectrometry. The experiments illustrated above revealed that, after incubation of 12-18 hours, the plates did not show any bacterial growth when the foaming composition of the invention was used and for the negative control, whereas for the experiments carried out in the absence of the composition of the invention, bacterial growth was observed in all the dishes analyzed (numerical ranges shown in parentheses in FIG. 3): 0.11±0.05 CFU/cm2 (mean value±standard deviation of the collected colonies, normalized for the total area of the six dishes, in the three experimental replicates).

[0098] The results illustrated above demonstrate that the foaming composition of the invention is capable of trapping microorganisms such as bacteria, viruses, spores, fungi, and parasites, preventing their volatilization.