METHODS AND COMPOSITIONS FOR TREATING AND COMBATTING TUBERCULOSIS

20230172973 · 2023-06-08

    Inventors

    Cpc classification

    International classification

    Abstract

    The invention provides one or more agent selected from nitric oxide (NO), a nitric oxide generating composition, a combination or combinable association of ingredients for a nitric oxide generating composition, and mixtures thereof, for use as an antibacterial agent against tuberculosis and Mycobacterium tuberculosis.

    Claims

    1.-10. (canceled)

    11. A method of treating or alleviating or preventing tuberculosis or an infection arising from the bacterium M. tuberculosis in a human or animal subject, comprising: administering to the human or animal subject an antibacterially effective amount of one or more agent selected from nitric oxide (NO), a nitric oxide generating composition, a combination or combinable association of ingredients for a nitric oxide generating composition, and mixtures thereof, wherein the agent is or comprises a nitric oxide generating composition or components thereof and wherein the nitric oxide generating composition or the combination or combinable association of ingredients for a nitric oxide generating composition comprises one or more nitrite salt, a proton source comprising one or more acid selected from organic carboxylic acids and organic non-carboxylic reducing acids, and one or more organic polyol.

    12. The method according to claim 11, wherein the agent for use in the method is an agent for use as an antibacterial agent against tuberculosis and Mycobacterium tuberculosis.

    13. The method according to claim 11, wherein the nitric oxide generating composition is prepared or preparable by a method which comprises mixing the nitrite salt, the proton source and the organic polyol components in desired proportions at a concentration higher than desired in the composition in the form in which it is to be used, to form a concentrate pre-mix, and subsequently diluting that concentrate pre-mix, suitably with water, to provide the composition to be used.

    14. The method according to claim 11, wherein the nitric oxide generating composition is prepared or preparable by a method which comprises mixing the nitrite salt, the proton source and the organic polyol components in desired proportions at the desired concentration for the composition in the form in which it is to be used, to provide the composition to be used.

    15. A method of treating a surface or space, which is a part of a human or animal body or an inanimate surface or space, to reduce the amount of viable M. tuberculosis bacteria on the surface or in the space, comprising: applying to the surface or the space or to a vicinity thereof an antibacterially effective amount of one or more agent selected from nitric oxide (NO), a nitric oxide generating composition, a combination or combinable association of ingredients for a nitric oxide generating composition, and mixtures thereof, wherein the agent is or comprises a nitric oxide generating composition or components thereof and wherein the nitric oxide generating composition or the combination or combinable association of ingredients for a nitric oxide generating composition comprises one or more nitrite salt, a proton source comprising one or more acid selected from organic carboxylic acids and organic non-carboxylic reducing acids, and one or more organic polyol.

    16. The method according to claim 15, wherein the agent for use in the method is an agent for use as an antibacterial agent against tuberculosis and Mycobacterium tuberculosis.

    17. The method according to claim 15, wherein the nitric oxide generating composition is prepared or preparable by a method which comprises mixing the nitrite salt, the proton source and the organic polyol components in desired proportions at a concentration higher than desired in the composition in the form in which it is to be used, to form a concentrate pre-mix, and subsequently diluting that concentrate pre-mix, suitably with water, to provide the composition to be used.

    18. The method according to claim 15, wherein the nitric oxide generating composition is prepared or preparable by a method which comprises mixing the nitrite salt, the proton source and the organic polyol components in desired proportions at the desired concentration for the composition in the form in which it is to be used, to provide the composition to be used.

    Description

    BRIEF DESCRIPTION OF THE DRAWINGS

    [0510] In the drawings:

    [0511] FIG. 1 shows a cumulative plot of nitric oxide evolved (nmol NO per mg nitrite) over time in the different reaction conditions of Example 1.

    [0512] FIGS. 2 to 16 show results from the various tests described in Example 2.

    [0513] FIG. 17 shows a schematic of the apparatus used for the SIFT-MS measurements.

    [0514] FIGS. 18 to 21 show results from various tests described in Example 3 with respect to antimicrobial activity against M. abscessus of a combination of known antibiotics, carboxylic acid solutions, carboxylic acid-nitrite solutions and carboxylic acid-nitrite-polyol solutions.

    [0515] FIG. 22 shows the results from the tests described in Example 4 with respect to the minimum inhibition concentration (MIC) against a large number of clinical isolate cultures for solutions containing citric acid, sodium nitrite and mannitol.

    [0516] FIG. 23 shows the results from the tests described in Example 5 with respect to antimicrobial activity against Pseudomonas aeruginosa for carboxylic acid-nitrite solutions with and without a polyol.

    [0517] FIGS. 24 to 27 show the results from the tests described in Example 6 with respect to antimicrobial activity against M. tuberculosis HN 878 in THP-1 cells.

    [0518] FIG. 28 shows the results from the tests described in Example 7 with respect to cytotoxicity (LDH cytotoxicity assay) and antimicrobial activity against H1N1 Influenza A virus in MDCK cells (a) at MOI=0.002 (.circle-solid.) and MOI=0.02 (.square-solid.) at a range of dilutions (the horizontal axis is the nitrite molarity) with the cytotoxicity shown in grey, cytotoxicity scale on the right-hand side (cytoxicity at the measured nitrite concentrations up to and including 0.015M was ≤1% of LDH control); and (b) plate photographs at MOI=0.002 and nitrite concentrations 0.15M, 0.015M and 0.0015M in comparison with oseltamivir (1 μM). The order of the plates recited in the previous sentence is the same as the order of the plates in the Figure going from left to right (there were two experiments, and the plates of each corresponding experiment are shown one above the other). The far right hand pair of plates, immediately to the right of the oseltamivir pair of plates, is the virus control. The cytotoxicity is shown below each pair of test plates, as the % of LDH control (mean of 3 LDH assays at 24 hours post-infection).

    [0519] FIG. 29 shows the results of a test of the effectiveness of an acidified solution of sodium nitrite, citric acid buffered to pH 5.8 using sodium hydroxide, and mannitol to kill M. abscessus in comparison with amikacin and negative controls under analogous conditions (described in Example 3).

    [0520] FIGS. 30 and 31 show in schematic form (FIG. 30) the embodiment of the present invention described in Example 10 for use in treatment of lung infections in a human subject, and (FIG. 31) a view of the point of contact between a liquid NO generating formulation and the lung tissue according to the present invention (right hand side of FIG. 31) in comparison with inhaled gaseous nitric oxide (left hand side of FIG. 31).

    [0521] FIG. 32 shows the results of the LDH cytotoxicity assay of Example 8 (Runs 1 & 2). The data is expressed as mean+standard deviation (SD) of two experiments. SD shown as the grey error bars. The maximum LDH activity (cells+lysis buffer) was set at 100% and all sample results are relative to this value. The LDH positive control was the positive control from the kit. The black bars (2 hour incubation) are the left-hand bar of each pair of bars in each case, and the red bars (24 hour incubation) are the right-hand bar of each pair of bars in each case.

    [0522] FIG. 33 shows the results of the antiviral testing against SARS-CoV-2 of Example 8 (Run 1) at MOI 3.0. In Run 1, one virus yield reduction assay was performed using SARS-CoV-2 at four multiplicities of infection (MOIs), confirmed using back titration of the inoculum virus. For cells inoculated with an MOI of 3, 2.1 log 10 TCID50/ml was found in the virus control well after titration. Reduction of SARS-CoV-2 yield might be observed for some of the conditions tested. After 24 hours of incubation, hardly any virus was detected in the lowest three MOIs (i.e. 0.3, 0.03 and 0.003). Possibly, 24 hours of replication on Vero E6 cells is not sufficient for obtaining high levels of progeny virus. The data is expressed as mean+standard deviation (SD) of two titrations. SD shown as the error bars. The horizontal dotted line level with the chloroquine and cell control log 10 TCID50/ml values is the limit of detection (LOD) of the assay.

    [0523] FIG. 34 shows the results of the antiviral testing against SARS-CoV-2 of Example 8 (Run 2) (a) at MOI 3.0 and (b) at MOI 0.3. The methodology corresponds to the parts of Run 1 at those MOIs, with the exception that the formulations are the Run 2 formulations and incubation was performed for 48 hours rather than 24 hours, in order to increase the level of progeny virus. The data is expressed as mean+standard deviation (SD) of two titrations. SD shown as the error bars. The horizontal dotted line level with the chloroquine and cell control log 10 TCID50/ml values is the limit of detection (LOD) of the assay.

    [0524] FIG. 35 shows the results of the antiviral testing against SARS-CoV of Example 9 at MOI 3.0. Prior to cell monolayer staining with crystal violet, 2 plates were microscopically checked and scored for cytopathic effect (CPE). A CPE, in the form of cell debris on top of an underlying monolayer, was found to be present in these plates. The results of the two plates, that were microscopically checked, is shown. Data are a single titration per condition. For the remaining plates, no CPE could be scored after crystal violet staining, due to a too dense cell monolayer. The horizontal dotted line level with the cell control log 10 TCID50/ml value is the limit of detection (LOD) of the assay.

    EXAMPLES

    [0525] The following non-limiting Examples are provided for further illustration of the present invention.

    Materials, Apparatus and Methods Used in Examples 1 and 2

    Solutions

    [0526] Stock solutions of 0.1 and 1 M citric acid (Health Supplies Limited, Thornton Heath, UK), 0.1 M sodium citrate (Fisher Scientific, Loughborough, UK), 1 M sodium nitrite (Sigma Aldrich, Dorset, UK), 0.5 and 1 M sorbitol (Special Ingredients, Chesterfield, UK), 0.5 and 1 M D-mannitol (Sigma Aldrich, Dorset, UK), 3 M sodium hydroxide (Fisher Scientific, Loughborough, UK), and 0.1 and 1 M L-ascorbic acid (ICN Biomedicals Inc., Ohio, US) were prepared by dissolving the appropriate mass in deionised water. Deionised water (18.2 MΩ) was obtained from an Arium Mini lab water system (Sartorius, Germany).

    [0527] Citric acid/citrate buffer solutions were prepared by two methods:

    [0528] 1. Titrating stock solutions of 0.1 M citric acid and 0.1 M sodium citrate using the volumes described by Sigma Aldrich, 2018 (https://www.sigmaaldrich.com/life-science/core-bioreagents/biological-buffers/learning-center/buffer-reference-center.html);

    [0529] 2. Dissolving a known mass of citric acid, for either a 0.1 M or 1 M preparation, in a small volume of deionised water then titrating a stock solution of 3 M sodium hydroxide and deionised water to achieve the desired buffer solution pH (pH 3 to pH 6.2).

    [0530] Ascorbic acid/ascorbate buffer solutions were prepared analogously, using ascorbic acid and, for Method 1, sodium ascorbate in place of citric acid and, for Method 1, sodium citrate.

    [0531] The inclusion of polyols was achieved by dissolving a known mass of sodium nitrite with stock solutions of the polyol (for example, either sorbitol or mannitol).

    [0532] The order of addition of the ingredients of the buffer solutions and stock is not critical, and any order of mixing can be used.

    [0533] All standard solutions were used within 48 hours of preparation. Calibration buffer solutions were prepared using phthalate (pH 4) and phosphate (pH 7) tablets (Fisher Scientific UK Ltd, Leicestershire, UK) dissolved in deionised water.

    Selected Ion Flow Tube Mass Spectrometry (SIFT-MS) Start-Up and Validation

    [0534] A Voice200 Selected Ion Flow Tube Mass Spectrometer (SIFT-MS) (Syft Technologies Ltd, New Zealand) was used for all the gas analyses described in this report. This instrument uses helium (BOC, Surrey, UK) as the carrier gas.

    [0535] Prior to analysis, the SIFT-MS was prepared for use with a simple start up procedure. The instrument was taken out of standby mode and a series of pressure checks were made to ensure that capillary flow is within the acceptable range for operation. This was followed by an automated validation procedure using the manufacturer's calibrant gas standard (Syft Technologies Ltd, New Zealand) containing benzene, toluene, ethylbenzene, and xylene. Finally, an in-house performance check was undertaken using a 10 ppm nitrogen dioxide standard (Air Products PLC, Surrey, UK).

    Procedure for the Generation of the NO

    [0536] The SIFT-MS equipment, reaction chamber and gas pathway was set up as illustrated in FIG. 17.

    [0537] The temperature in the reaction chamber was continuously monitored with a HT1 Temperature Smart Sensor (SensorPush, New York, US). The reaction chamber, a 670 mL plastic (bisphenol A free (BPA free)) clip lock tub with silicone seal (Tesco, Welwyn Garden City, UK) was attached to a pump that continuously cycles humid air through the chamber and over the SIFT-MS inlet capillary. Humidification was achieved by pumping air through two Dreschel bottles containing deionised water in a method analogous to that described by Vernon, W., and Whitby, L. (1931) The quantitative humidication of air in laboratory experiments, Trans. Faraday Soc. 27, 248-255. This system was allowed to equalise for 30 minutes before use. A continuous SIFT-MS scan was begun for the real-time detection and quantification of NO, NO.sub.2, and HONO. Once a stable baseline reading was observed (consistent concentration for >2 minutes) for these compounds, the sample was placed in the reaction chamber and monitored for three hours.

    [0538] After SIFT-MS validation the capillary inlet extension heated to 120° C. was attached to the outlet of the reaction chamber via a T-junction, allowing the SIFT-MS to sample the gases flowing out from the reaction chamber in real time.

    [0539] The sample was prepared by weighing a circa 0.3 cm×0.3 cm carded non-woven 20 grams per square metre (20 gsm) polypropylene mesh from RKW-Group, Frankenthal, Germany in a weighing boat (˜3 mg). This was reweighed after an addition of a 10 μL droplet of test or control solution onto the centre of the mesh (it was ensured that the droplet soaked into the mesh). Finally, the loaded mesh in the weighing boat was placed in the reaction chamber and a final 10 μL droplet of buffer solution was pipetted onto the centre of the mesh. The reaction chamber was promptly sealed and the generation of nitrogenous species was observable instantaneously at the SIFT-MS interface.

    Analysis of Generated Gas

    [0540] The generated gas was analysed using the selected ion mode of the SIFT-MS and scans were performed in sequential batches each lasting 1000 seconds. The following product masses were repeatedly scanned for: 30 m/z for nitrous acid, 48 m/z for nitrous acid, 46 m/z for nitrogen dioxide, and 30 m/z for nitric oxide. These measurements were achieved using all three of the positive precursor ions: hydronium (H.sub.3O.sup.+), nitrosium (NO.sup.+), and dioxygenyl (O.sub.2.sup.+). The air flowed through the chamber at 660 ml/min and the SIFT-MS inlet sampled this air stream at a flow rate of 2.7 ml/min.

    pH Measurements for All Examples

    [0541] A Five Easy pH meter (Mettler Toledo, Switzerland) with a glass electrode, LE438 probe, was used for all pH measurements. The accuracy of this electrode was ensured with a second pH meter; the hand-held 205 probe (Testo, Alton, US). Fresh calibrant buffer solutions were used for daily calibration of the pH meters.

    Example 1

    [0542] Generation of Nitric Oxide Using 1 M/c. DH 3 Citric Acid Contacting a Mesh Containing Imbibed 1 M Sodium Nitrite with and without 1 M Polyols

    [0543] The SIFT-MS equipment, reaction chamber and gas pathway was set up as described above and illustrated in FIG. 17.

    [0544] Two test solutions of 1 M sodium nitrite containing respectively 1 M mannitol and 1 M sorbitol were imbibed into the mesh as described above to make two test meshes.

    [0545] A control solution of 1 M sodium nitrite with no polyol was imbibed into the mesh as described above to make a control mesh.

    [0546] A buffer solution of 1 M citric acid/citrate buffer prepared by either of the two methods 1 and 2 described above and having a pH of about 3 was added to each of the test and control meshes in each test to initiate gas generation as described above.

    [0547] The results are shown in FIG. 1.

    [0548] The data show that the 1 M sodium nitrite imbibed mesh contacted with 1 M/c. pH 3 citric acid generated markedly greater amounts of nitric oxide when the mesh also contained 1 M mannitol or 1 M sorbitol (mannitol has a greater effect than sorbitol) than when no polyol was present.

    Example 2

    Investigation of the Effects of Different Carboxylic Acids, Acid Concentration, DH and Polyols on the Generation of Nitric Oxide

    [0549] Samples were prepared as above, varying the organic acid, pH and polyol as follows:

    TABLE-US-00001 Buffer added to mesh (where alternative buffers Test solution Control solution are indicated they are used imbibed into mesh imbibed into mesh in separate runs, as reported Experiment in each test run in control run in the relevant Figure) A (FIG. 2) 1M sodium nitrite — 1M citric acid/ citrate (pH about 3) 1M ascorbic acid/ ascorbate (pH about 3) B (FIG. 3) 1M sodium nitrite 1M sodium nitrite 1M citric acid/citrate containing 1M sorbitol (pH about 3) 1M sodium nitrite containing 1M mannitol 1M sodium nitrite containing 1M xylitol 1M sodium nitrite containing 1M arabitol C (FIG. 4) 1M sodium nitrite 1M sodium nitrite 1M ascorbic acid/ containing 1M sorbitol ascorbate 1M sodium nitrite (pH about 3) containing 1M mannitol 1M sodium nitrite containing 1M xylitol 1M sodium nitrite containing 1M arabitol D (FIG. 5) 1M sodium nitrite — 1M citric acid/ containing 0.5M sorbitol citrate 1M sodium nitrite (pH about 3) containing 0.5M mannitol 1M sodium nitrite containing 0.5M xylitol 1M sodium nitrite containing 0.5M arabitol E (FIG. 6) 1M sodium nitrite — 1M ascorbic acid/ containing 0.5M sorbitol ascorbate 1M sodium nitrite (pH about 3) containing 0.5M mannitol 1M sodium nitrite containing 0.5M xylitol 1M sodium nitrite containing 0.5M arabitol F (FIG. 7) 1M sodium nitrite — 0.5M citric acid/ containing 1M arabitol citrate (pH about 3) 0.5M ascorbic acid/ ascorbate (pH about 3) G (FIG. 8) 1M sodium nitrite — 0.5M citric acid/ containing 1M mannitol citrate (pH about 3) 0.5M ascorbic acid/ ascorbate (pH about 3) H (FIG. 9) 1M sodium nitrite 1M sodium nitrite 1M citric acid/ containing 1M sorbitol citrate (pH about 3) 1M sodium nitrite 1M ascorbic acid/ containing 1M mannitol ascorbate (pH about 3) 1M sodium nitrite containing 1M xylitol 1M sodium nitrite containing 1M arabitol I (FIG. 10) 1M sodium nitrite — 1M citric acid/ containing 0.5M sorbitol citrate (pH about 3) 1M sodium nitrite 1M ascorbic acid/ containing 0.5M mannitol ascorbate (pH about 3) 1M sodium nitrite containing 0.5M xylitol 1M sodium nitrite containing 0.5M arabitol J (FIG. 11) 1M sodium nitrite 1M sodium nitrite 0.5M citric acid/ containing 0.5M mannitol citrate (pH about 3) K (FIG. 12) 1M sodium nitrite 1M sodium nitrite 0.5M citric acid/ containing 0.5M mannitol citrate (pH about 4.8) L (FIG. 13) 1M sodium nitrite 1M sodium nitrite 0.5M citric acid/ containing 0.5M mannitol citrate (pH about 6.2) M (FIG. 14) 1M sodium nitrite 1M sodium nitrite 1M citric acid/ containing 1M glycerol citrate (pH about 2) 1M sodium nitrite containing 2M glycerol N (FIG. 15) 1M sodium nitrite 1M sodium nitrite 1M citric acid/ containing 1M mannitol citrate (pH about 2) 1M sodium nitrite containing 1M sorbitol 1M sodium nitrite containing 1M mannitol and 1M glycerol 1M sodium nitrite containing 1M sorbitol and 1M glycerol O (FIG. 16) 1M sodium nitrite 1M sodium nitrite 1M citric acid/ containing 0.5M mannitol citrate (pH 5.8)

    [0550] The SIFT-MS equipment, reaction chamber and gas pathway was set up as described above and illustrated in FIG. 17.

    [0551] Test solutions as described above were imbibed into the mesh as described above to make the test meshes.

    [0552] Where used, a control solution of 1 M sodium nitrite with no polyol was imbibed into the mesh as described above to make a control mesh.

    [0553] The or each buffer solution as described above prepared by either of the two methods 1 and 2 described above and having the pH described above was added to each of the test and, if used, control meshes in each test to initiate gas generation as described above.

    [0554] The results are shown in FIGS. 2 to 13. “Normal” in the Figures refers to no polyol being present.

    [0555] FIG. 2 compares the rate of NO evolution as produced by citric acid/citrate buffer or ascorbic acid/ascorbate buffer (pH circa 3) in the absence of a polyol. The graphs clearly show that citric acid/citrate buffer generates a higher initial burst and the evolution last at for longer at a higher level than for ascorbic acid/ascorbate buffer. The citric acid/citrate buffer trace peaks at about 55000 ppb whereas the ascorbic acid/ascorbate buffer trace peaks at about 28000 ppb.

    [0556] FIG. 3 relates to a citric acid/citrate buffer and nitrite system with and without polyols. Polyol concentration is 1M. The rates of evolution, initial burst and consequent release over time are altered in the presence of polyols when compared to no polyol. Xylitol and mannitol produce the highest peak, followed by sorbitol, then no polyol, and then arabitol. In the 500-1000 s region xylitol and arabitol have the highest outputs, followed by mannitol, sorbitol and then no polyol. Peak burst mannitol=xylitol (about 64000 ppb)>sorbitol (about 53000 ppb)>no polyol (about 50000 ppb)>arabitol (about 40000 ppb).

    [0557] FIG. 4 relates to an ascorbic acid/ascorbate buffer and nitrite system, with and without polyols. Polyol concentration is 1M. Peak burst mannitol (about 40000 ppb)>arabitol (about 35000 ppb)>xylitol=no polyol (about 30000 ppb)>sorbitol (about 23000 ppb), i.e. a different sequence to the citric acid/citrate buffer system of FIG. 3.

    [0558] FIG. 5 relates to a citric acid/citrate buffer and nitrite system, with and without polyols (the “no polyol” line, which has a peak burst approximately the same as the mannitol line, has been omitted for clarity). Polyol concentration is 0.5M. Peak burst arabitol (about 76000 ppb)>>no polyol=mannitol (about 48000 ppb)>xylitol=sorbitol (about 40000 ppb). It will be seen that this is a different sequence compared to the analogous 1M polyol citric acid/citrate buffer system (FIG. 3), showing that the polyol effect is polyol-concentration dependent.

    [0559] FIG. 6 relates to an ascorbic acid/ascorbate buffer and nitrite system, with and without polyols (the “no polyol” line, which has a peak burst approximately the same as the sorbitol line, has been omitted for clarity. Polyol concentration is 0.5M. Peak burst xylitol (about 50000 ppb)>mannitol (about 38000 ppb)>sorbitol=no polyol (about 30000 ppb)>arabitol (about 23000 ppb). Again, a different sequence is observed in comparison with the analogous citric acid/citrate buffer (0.5M polyol) and ascorbic acid/ascorbate (1M polyol) systems (FIGS. 5 and 4 respectively). The polyol effect is thus demonstrated to be polyol-chemistry/stereo-chemistry and polyol-molarity dependent.

    [0560] FIGS. 7 and 8 compare the rate of NO evolution with citric acid/citrate buffer or ascorbic acid/ascorbate buffer and the presence of a polyol (0.5M). These graphs emphasise some of the differences observed in the FIGS. 2 to 6. The citric acid/citrate buffer trace in FIG. 7 peaks at about 76000 ppb whereas the ascorbic acid/ascorbate buffer trace peaks at about 22000 ppb. The citric acid/citrate buffer trace in FIG. 8 peaks at about 48000 ppb whereas the ascorbic acid/ascorbate buffer trace peaks at about 38000 ppb.

    [0561] FIG. 9 compares cumulative outputs for 1M polyol concentrations. The differences at say 3000 s for ascorbic acid/ascorbate buffer are small, in order mannitol>sorbitol=arabitol>xylitol. For citric acid/citrate buffer at 3000 s the order is xylitol>arabitol>mannitol>sorbitol>no polyol.

    [0562] The data show that the output of nitric oxide can be increased by up to, or even more than, about 100/6, for example as between no polyol (curve E, which obtains a cumulative nitric oxide evolution of about 10000 nmol per mg nitrite after 3000 s, which is even then still rising) and xylitol (curve A, which obtains a cumulative nitric oxide evolution of about 20000 nmol per mg nitrite after the same time, which also is still rising).

    [0563] FIG. 10 compares cumulative outputs for 0.5M polyol concentrations. For citric acid/citrate buffer at 3000 s the order is arabitol>mannitol=xylitol>sorbitol>no polyol (the “no polyol” line for citric acid/citrate buffer, lying below the sorbitol line, has been omitted for clarity). For ascorbic acid/ascorbate buffer at 3000 s the order is xylitol>mannitol>sorbitol>arabitol. Again this order is different compared to 1M polyol (FIG. 9).

    [0564] FIGS. 11 to 13 compare the cumulative plots for citric acid/citrate buffer 1M and sodium nitrite (1M), with and with mannitol (0.5M) and at different pH. As the pH increases the differences become smaller and at pH 6.2 the differences have disappeared. So it is seen from these experiments that the polyol effect is also pH dependent.

    [0565] FIG. 14 shows the cumulative NO (nmol/cm.sup.2 mesh area) output for citric acid/citrate buffer (1M, pH circa 2) with and without glycerol (1M and 2M) present in the 1M sodium nitrite solution. Over the first 2000 s the NO outputs for 1M and 2M glycerol are slightly lower than for no polyol present. At longer times the glycerol containing formulations have greater output with the 2M glycerol having the greater output.

    [0566] FIG. 15 shows the cumulative NO (nmol/cm.sup.2 mesh area) output for citric acid/citrate buffer (1M, pH circa 2) and 1M sodium nitrite solutions, with or without polyols present in the nitrite solution. The plots show that the inclusion of glycerol in mannitol/nitrite solutions reduces the output compared to when no glycerol is present. Surprisingly, however, unlike the case for mannitol, the inclusion of glycerol in sorbitol/nitrite solutions enhances the NO output compared to the output when no glycerol is present.

    [0567] When glycerol was used a 1M glycerol solution was first made and used to make 1M sorbitol or 1M mannitol solution which in turn was used to make 1M nitrite solution.

    [0568] FIG. 16 shows the cumulative NO output (mol/mg nitrite) for citric acid/citrate buffer (1M, pH 5.8), with and without mannitol (0.5M) present in the sodium nitrite (1M) solution. The plots show that the inclusion of the polyol gives rise to a greater NO output after circa 2000 s reaction time.

    [0569] FIG. 16 shows that, at physiologically important pH levels of greater than about 5, particularly greater than about 5.5, mannitol enhances the generation of nitric oxide in comparison with the same system without mannitol, providing cumulative levels of 1400 nmol NO per mg nitrite after 10000 s (167 minutes).

    Example 3

    [0570] Activity Against M. abscessus Cultures with Various Organic Acid and Nitrite Solutions with and without Polyols

    Materials

    [0571] 4.7 g Middlebrook 7H9 broth base (Sigma-Aldrich) was reconstituted with 900 ml of distilled water and autoclaved at 121° C. for 15 minutes. Middlebrook ADC growth supplement (Sigma-Aldrich) was added to the autoclaved 7H9 solution (50 ml per 450 ml, total of 100 ml added).

    [0572] 1M Sodium nitrite (Emsure): Dissolve 6.9 g of sodium nitrite powder in 100 ml of distilled water in a clean screw top glass bottle. Autoclave the mixture at 121° C. for 15 minutes.

    [0573] 1M Citric acid (Sigma-Aldrich): Dissolve 19.2 g of Citric acid powder in 100 ml of distilled water in a clean screw top glass bottle. Autoclave the mixture at 121° C. for 15 minutes.

    [0574] 1M Ascorbic acid (Sigma-Aldrich): Add 17.6 g of Ascorbic acid powder to a sterile glass bottle. Dissolve thoroughly in 100 ml of sterilised distilled water. Due to its short half-life it was prepared on a daily basis, using strict sterile techniques. It was not autoclaved due to its inherent instability but was filtered through a 0.2μ filter before use.

    [0575] 1M Sodium citrate tribasic dihydrate (Sigma-Aldrich): Dissolve 29.4 g of sodium citrate powder in 100 ml of distilled water in a clean screw top glass bottle. Autoclave the mixture at 121° C. for 15 minutes.

    [0576] 1M L-Ascorbic acid sodium salt (Acros Organics): Dissolve 19.8 g of sodium ascorbate powder in 100 ml of distilled water in a clean screw top glass bottle. Autoclave the mixture at 121° C. for 15 minutes.

    [0577] For the experiments with polyols, D-mannitol (Sigma-Aldrich) was used. The polyol was added to the sodium nitrite stock solution described above to form the following stock solutions:

    [0578] Stock solution A—1M sodium nitrite & 0.5M mannitol

    [0579] Stock solution B—1.5M sodium nitrite & 0.5M mannitol

    [0580] A stock solution of 1.5M citric acid was also prepared.

    [0581] The molarity of each component was adjusted for dilution factors to ensure the correct final molarity of each experimental solution.

    Mycobacterium abscessus (MAB)

    [0582] Laboratory reference strain Mycobacterium abscessus ATCC 19977 lux was used for all experimental conditions in this example.

    Methodology

    [0583] 50 ml falcon tubes were labelled Tube T (test suspension), Tube A (acid control) and Tube C (control).

    [0584] 8 ml of 7H9+ADC supplement was added to each tube. 100 μl of MAB suspension (grown previously to approximately 3-4 McFarland standard) was then added. The baseline relative light unit (RLU) reading of the MAB suspension was taken. The contents were mixed by vortexing.

    Tube Contents when a Polyol (Mannitol) was not Present

    [0585] Tube T: 1 ml of sodium nitrite (1M) solution were added to the tube, immediately followed by 1 ml citric acid solution (1M) or ascorbic acid solution (1M) to give a final concentration of 0.1M in 10 ml. The contents were mixed by gentle inversion and incubated for 24 hours at 37° C.

    [0586] Tube A: 1 ml of citric acid solution (1M) or ascorbic acid solution (1M) were added to the tube, and 1 ml of sterile distilled water to produce a final volume of 10 ml to test a 0.1M concentration to acid. The contents were mixed by gentle inversion and incubated for 24 hours at 37° C.

    [0587] Tube C: 2 ml of sterile distilled water were added to the tube to make a total volume of 10 ml. This is the control to assess growth under optimal conditions. The contents were mixed by gentle inversion and incubated for 24 hours at 37° C.

    Tube T Contents when a Polyol (Mannitol) was Present

    [0588] When mannitol was present the tube T contents were as follows: [0589] 1. Tube T: 1 ml sodium nitrite (1M) & mannitol (0.5M) and 1 ml of citric acid (1M) [0590] 2. Tube T: 1 ml sodium nitrite (1.5M) & mannitol (0.5M) and 1 ml of citric acid (1M) [0591] 3. Tube T: 1 ml sodium nitrite (1M) & mannitol (0.5M) and 1 ml of citric acid (1.5M)

    [0592] RLUs were measured at 30 minutes, 60 minutes and 24 hours incubation to assess the activity of the T, A and C solutions.

    [0593] Following 24 hours of incubation Tube C, Tube A and Tube T were plated on to Columbia Blood Agar (VWR Chemicals). The plates were incubated at 37° C. for 72 hours. Colony forming units (CFU) were read at day 3, 5 and 7 of incubation. All work was undertaken in a CL2 biological safety cabinet within a CL2 laboratory facility.

    [0594] The results are shown in FIGS. 18 to 21.

    [0595] FIG. 18 shows that a solution of 0.1 M citric acid and 0.1 M nitrite (Tube T) is effective at eliminating the M. abscessus culture after 7 days pH of 5 and 5.5 and reducing the M. abscessus cultures compared to the 0.1 M citric acid only solution (Tube A) at pH values of 6.0, 6.5, 7.0 and 7.4. FIG. 18 also shows that a solution of 0.1 M ascorbic acid and 0.1 M nitrite (Tube T) is effective at eliminating the M. abscessus culture after 7 days at pH values of 5.0, 5.5, and 6.0, and reducing the M. abscessus cultures compared to the ascorbic acid only solution (Tube A) at pH values of 6.5, 7.0 and 7.4.

    [0596] FIG. 19 a) shows that a solution of 0.1 M citric acid and 0.1 M nitrite is effective at reducing the CFU of the M. abscessus culture after three days of incubation and a solution of 0.1 M citric acid and 0.1 M nitrite with 0.05 M mannitol is effective at almost entirely eliminating the M. abscessus culture after three days of incubation. FIG. 19 b) shows that a solution of 0.1 M citric acid and 0.1 M nitrite without mannitol is effective at maintaining a reduced CFU of M. abscessus after five days of incubation. The Figure also shows that the solution of 0.1 M citric acid and 0.1 M nitrite with 0.05 M mannitol is effective at reducing the CFU of M. abscessus culture after five days of incubation.

    [0597] FIG. 20 a) shows that a solution of 0.15 M citric acid and 0.1 M nitrite is effective at reducing the CFU of the M. abscessus culture after three days of incubation and a solution of 0.15 M citric acid and 0.1 M nitrite with 0.05 M mannitol is effective at eliminating the M. abscessus culture after three days of incubation. FIG. 20 b) shows that the solution of 0.15 M citric acid and 0.1 M nitrite without mannitol is effective at maintaining a reduced CFU of M. abscessus after five days of incubation. The figure also shows that the solution of 0.15 M citric acid and 0.1 M nitrite with 0.05 M mannitol is effective at eliminating the M. abscessus culture after five days of incubation.

    [0598] FIG. 21 shows that a solution of 0.1 M citric acid and 0.15 M nitrite is effective at reducing the CFU of the M. abscessus culture after three days of incubation and maintaining the reduction of CFU of the M. abscessus culture after 5 days of incubation. The figure also shows that a solution of 0.1 M citric acid and 0.15 M nitrite with 0.05 M mannitol is effective at eliminating the M. abscessus culture after three and five days of incubation.

    Example 4

    [0599] Minimum Inhibition Concentrations (MIC) of Carboxylic Acid-Nitrite-Polyol Solutions Against Mycobacterium abscessus (Mabs) and Mycobacterium tuberculosis (Mtb) in a Range of Clinical Isolate Cultures

    Healthy Volunteers

    [0600] Peripheral blood samples were taken from healthy volunteers who had provided written informed consent (ethical approval reference REC No. 12/WA/0148).

    Mycobacterial Strains

    [0601] Mycobacterium abscessus (ATCC 19977) and Mycobacterium tuberculosis (H37RV) strains both contained a bacterial luciferase (lux) gene cassette (luxCDABE) which enabled measurement of relative light units (RLU), as well as conventional colony forming unit (CFU) measurement of bacterial survival.

    General Reagents

    [0602]

    TABLE-US-00002 Reference Supplier 24 Well Cell Culture Cluster 3526 Costar Corning, USA CD14 microbeads, human 130-150-201 Miltenyi Biotec, UK Citric acid 791725 Sigma, UK Columbia Blood Agar plates 100253ZF vWR, UK Decanal D7384 Sigma, UK Dulbecco's Modified Eagle D6429 Sigma, UK Medium -High Glucose FLUOstar Omega BMG Labtech, UK Foetal Bovine Serum P30-3702 Pan-Biotech, UK GloMax-96 Luminometer Promega, UK Mannitol M4125 Sigma, UK Middlebrook 7H11 agar plates PP4080 E&O Labs, UK Middlebrook 7H9 broth M0178 Sigma, UK Mycobacterium abscessus 19977 ATCC Mycobacterium tuberculosis H37RV ATCC Penicillin Streptomycin P0781 Sigma, UK Recombinant Human GM-CSF 300-03 PeproTech EC, UK Recombinant Human IFNγ 300-02 PeproTech EC, UK Sodium Nitrite 1.06549.0500 Merck, Germany

    Treatment Conditions

    [0603] Treatment 1: Citric acid 0.15M, sodium nitrite 0.1M and mannitol 0.05M

    [0604] Treatment 2: Citric acid 0.1M, sodium nitrite 0.15M and mannitol 0.05M

    Broth Microdilution Minimum Inhibitory Concentration (MIC)

    [0605] The MIC for each treatment against M. abscessus and M. tuberculosis was undertaken according to the guidelines (M07-A9) produced by the Clinical and Laboratory Standards Institute for antimicrobial susceptibility testing. Doubling dilutions of each treatment was made across the plates, and the plates incubated at 37° C., and read at day 3 and 7 for Mabs. and days 14 and 21 for Mtb. Testing was undertaken in duplicate.

    [0606] All work was undertaken in a CL2 biological safety cabinet within a CL2 laboratory facility.

    [0607] It was found that the minimum inhibitory concentration for a 1.5 M citric acid, 1 M sodium nitrite and 0.5 M mannitol solution against M. abscessus is 4.7 mM. It was further found that the minimum inhibitory concentration for a 1.5 M citric acid, 1 M sodium nitrite and 0.5 M mannitol solution against M. tuberculosis is 2.3 mM.

    [0608] It was found that the minimum inhibitory concentration for a 1 M citric acid, 1.5 M sodium nitrite and 0.5 M mannitol solution against M. abscessus is 3.1 mM. It was further found that the minimum inhibitory concentration for a 1 M citric acid, 1.5 M sodium nitrite and 0.5 M mannitol solution against M. tuberculosis is 1.6 mM.

    [0609] Minimal inhibitory concentration (MIC) was also carried out by broth microdilution using isolates Nos. 570, 571, 573, 575, 578, 579, 580, 581, 582, 583, 584, 585, 589, 591, 592, 593, 594, 595, 596, 597, 598, 599, 600, 601, 602, 603, 604, 605, 606, 607, 608, 616, 617, 619, 812, 825, 829, 839, 845, 848, 853, 857, 858, 873, 894, 898, 909, 919, 928, 932, 942, 944, 955, 956, 959, 963, 964, 965, 968, 975, 980, 982, 985, 993, 995, 1000, 1001, 1007, 1011, 1017, 1023, 1024, 1026, 1027, 1042, 1043, 1045, 1047, 1049, 1054, 1063, 1066, 1067, 1070, 1072, 1073, 1074, 1075, 1076, 1077, 1078, 1079, 1082, 1086, 1094, 1096, 1101, 1103, 1104 and 1106 from the Floto Laboratory, Cambridge University, UK (https://www.flotolab.com/) M. abscessus clinical isolate library. Each individual isolate was assessed in duplicate.

    [0610] The results for the tests on the clinical isolates are shown in FIG. 22 a) and b). The graphs show the MIC of nitric oxide against M. abscessus in duplicate with readings taken after three, four and five days of incubation of the isolates. The plates were also read at day 7 of incubation but there was no difference seen, compared to day 5. The laboratory strain ATCC 19977 lux was used as a control in both experiments and shows comparative results to the clinical isolates.

    [0611] FIG. 22 shows that citric acid-nitrite-mannitol solutions have an effect across a broad range of clinical isolates. The minimum inhibition concentrations for a majority of clinical isolates were within 0.02 M for the 0.1 M citric acid, 0.15 M nitrite and 0.05 M mannitol solutions (FIG. 22a) and the minimum inhibition concentrations for a majority of clinical isolates were within 0.04 M for the 0.15 M citric acid, 0.1 M nitrite and 0.05 M mannitol solutions (FIG. 22b).

    [0612] In both figures the MIC on certain samples differed on different days. Those are the samples with more than one dot shown above the identification code of the isolate sample. Generally speaking, in that situation the higher MIC was observed on later days of incubation than the lower MIC. Overall, the combination with the lower citric acid (0.1 M) and the higher sodium nitrite (0.15 M) (FIG. 22(a)) is more effective than the combination with the higher citric acid (0.15 M) and the lower sodium nitrite (0.1 M) (FIG. 22(b)).

    [0613] Additional data showing in vitro killing of M. abscessus by carboxylic acid-nitrite-polyol solutions is shown in FIG. 29. In this figure, the M. abscessus killing effectiveness of an aqueous formulation of sodium nitrite, citric acid buffered to pH 5.8 using sodium hydroxide solution, and mannitol is demonstrated in comparison with amikacin and negative controls over a 24 hour period under analogous conditions.

    Example 5

    [0614] Antimicrobial Activity Against Pseudomonas Aeruginosa for Carboxylic Acid-Nitrite Solutions with and without a Polyol

    Equipment and Media

    [0615] UKAS calibrated pipettes (100-1000 μL range)—Proline® Plus

    [0616] UKAS calibrated multichannel pipettes (P300 and P20)—Gilson®, UK

    [0617] Universal tubes—SLS, UK

    [0618] Calibrated balance—HR-100A

    [0619] Microbiological incubator—Heratherm™, ThermoFisher Scientific, UK

    [0620] Tryptone Soya Agar (TSA)—Southern Group Laboratories, UK

    [0621] Tryptone Soya Broth (TSB)—Acumedia®, SLS, UK

    [0622] Malt Agar—Acumedia®, Acumedia®, SLS, UK

    [0623] Brain Heart Infusion Broth (BHIB)—Acumedia®, SLS, UK

    [0624] Sabouraud Dextrose Broth (SDB)—Acumedia®, SLS, UK

    [0625] Dey-Engley Neutraliser (DE-N)—Acumedia®, SLS, UK

    [0626] Citric Acid—Sigma, UK

    [0627] Sodium Nitrite—Sigma, UK Mannitol—Sigma, UK

    [0628] Sorbitol—Sigma, UK

    Test Microorganisms

    [0629] Pseudomonas aeruginosa NCTC 13618—Isolated from a Cystic Fibrosis Patient

    Formulations

    [0630]

    TABLE-US-00003 Formulation 1 Liquid Citric Acid sodium nitrite pH 5.2 Formulation 2 Liquid Citric Acid sodium nitrite pH 6.0 Formulation 3 Liquid Citric Acid sodium nitrite pH 5.2 with mannitol Formulation 4 Liquid Citric Acid sodium nitrite pH 6.0 with mannitol Formulation 5 Liquid Citric Acid sodium nitrite pH 5.2 with sorbitol Formulation 6 Liquid Citric Acid sodium nitrite pH 6.0 with sorbitol Positive control Liquid N/A N/A Negative control Liquid N/A N/A Concentration 1 - 1M Citric acid plus 1M sodium nitrite (with ot without 0.5M polyol) Concentration 2 - 0.5M Citric acid plus 1M sodium nitrite (with ot without 0.5M polyol) Concentration 3 - 0.5M Citric acid plus 0.5M sodium nitrite (with ot without 0.5M polyol)

    Dey-Engley Neutraliser Validation

    [0631] Twenty-four-hour cultures of Pseudomonas aeruginosa were harvested from Tryptone Soya Agar (TSA) and used to prepare a 1×108±5×107 CFUmL.sup.−1 suspension. This was further diluted in Brain Heart Infusion Broth (BHIB) to prepare a 1×105±5×104 CFUmL.sup.−1 working suspension.

    [0632] The starting inoculum was confirmed by serial dilution and spread plating. The neutraliser validation was performed using control (9 mL Phosphate Buffered Saline (PBS) and 1 mL inoculum), toxicity (9 mL Dey-Engley neutraliser (DE-N) and 1 mL inoculum), and neutraliser efficacy (8 mL neutraliser, 1 mL test agent and 1 mL inoculum) samples. Following a 5-minute treatment, 200 μL of suspension was removed from each tube, serially diluted and 100 μL was plated onto TSA. Agar plates were incubated at 37±2° C. for 18-24 hours.

    Antimicrobial Efficacy Against Planktonic Organisms

    [0633] Twenty-four-hour cultures of P. aeruginosa were harvested from TSA and used to prepare a 1×10.sup.8±5×107 CFUmL.sup.−1 suspension. This was further diluted in BHIB to prepare a 1×10.sup.6±5×10.sup.4 CFUmL.sup.−1 working suspension. Universal tubes were filled with 8 mL bacterial solution.

    [0634] One ml of citric acid solution and 1 mL of sodium nitrite solution were added to each test agent to give the required concentration as described above. Solutions were incubated at 37±2° C. for 24 hours. Following the incubation period, 1 mL was removed from each tube and transferred to a tube containing 9 mL neutraliser. Viable organisms were quantified using serial dilutions and plate counting.

    [0635] The results are shown in FIG. 23.

    [0636] The data show the antimicrobial effectiveness against Pseudomonas of: [0637] citric acid (1 M) mixed with nitrite (1 M) with and without polyol (0.5 M) (“Conc. 1”); [0638] citric acid (0.5 M) mixed with nitrite (1 M) with and without polyol (0.5 M) (“Conc. 2”); and [0639] citric acid (1 M) mixed with nitrite (0.5 M) with and without polyol (0.5 M) (“Conc. 3”).

    [0640] The citric acid solution is at pH 5.2 (for Formulations 1, 3 and 5) and 6.0 (for Formulations 2, 4 and 6). Formulations 1 and 2 contain no polyol; Formulations 3 and 4 include mannitol; and Formulations 5 and 6 contain sorbitol.

    [0641] Good efficacy is shown for all formulations at pH 5.2. At pH 6, the formulations comprising mannitol are marginally more effective.

    Example 6

    [0642] The efficacy of formulations including nitrite salt, organic acid and polyol against M. tuberculosis HN 878 in THP-1 cells was evaluated.

    Formulations

    [0643] Formulations were prepared as set out in the following table. Where the preparation method is stated as “concentrate”, denoted by the suffix FC in the Sample Reference, this means that the formulation was initially made up as a concentrated pre-mix containing all three ingredients sodium nitrite (0.75M), polyol (0.25M) and acid (0.5M), and then diluted with distilled water to arrive at the desired concentration of each as stated in the table. Where the preparation method is stated as “dilute”, denoted by the suffix FD in the Sample Reference, this means that the formulation was initially made up as a pre-mix containing all three ingredients at the desired concentration initially, namely sodium nitrite (0.15M), polyol (0.05M) and acid (0.1M), and then diluted with distilled water to arrive at the desired concentration of each as stated in the table.

    [0644] Within each formulation, a range of concentrations of the sodium nitrite was prepared by serial dilution, namely 16, 8, 4, 2, 1, 0.5, 0.25 and 0.125 μg/ml for the in vitro bacterial inhibition assays against M. tuberculosis HN878.

    TABLE-US-00004 Sample Preparation Test Mixture (final molarity post dilution) Reference Method Sodium Nitrite Polyol Acid Formulation 1 30RESP001FC concentrate sodium nitrite 0.15M mannitol 0.05M citric acid/citrate 0.1M 30RESP001FD dilute sodium nitrite 0.15M mannitol 0.05M citric acid/citrate 0.1M Formulation 2 30RESP002FC concentrate sodium nitrite 0.15M lactitol 0.05M citric acid/citrate 0.1M 30RESP002FD dilute sodium nitrite 0.15M lactitol 0.05M citric acid/citrate 0.1M Formulation 3 30RESP003FC concentrate sodium nitrite 0.1M mannitol 0.05M citric acid/citrate 0.1M 30RESP003FD dilute sodium nitrite 0.1M mannitol 0.05M citric acid/citrate 0.1M Formulation 4 30RESP004FC concentrate sodium nitrite 0.1M mannitol 0.05M ascorbic acid/ascorbate 0.1M 30RESP004FD dilute sodium nitrite 0.1M mannitol 0.05M ascorbic acid/ascorbate 0.1M

    [0645] MIC macrophage testing was performed using a THP-1 macrophage (1) compound screening assay.

    [0646] Macrophage Preparation and Culture: THP-1 cells were expanded for 2 weeks. Thereafter, THP-1 cells were suspended in complete DMEM media for macrophages at a concentration of 5×10.sup.5 cells/mL. The cells were seeded into 24 well tissue culture plates, 2 mL per well (1×10.sup.6 per well). One 24-well plate of cells allows for arrange of 7 drug concentrations plus untreated controls to be tested in triplicate. In addition to the drug assay plates, one extra plate was seeded (or at least 3 additional wells) for determining bacterial uptake on the day of infection. The cells were incubated at 37° C. at 5% CO.sub.2 in a humidified chamber. DMEM antibiotic/antimycotic-free complete media were not changed during the 3 day assay.

    Complete DMEM Media for Macrophages:

    [0647] Dulbecco's Modification of Eagle's Medium (Cellgro 15-017-cv) supplemented with:

    [0648] Heat-inactivated fetal calf serum (Atlas Biologicals, Fort Collins, Colo., F-0500-A) (10%)

    [0649] L929-conditioned medium (10%)

    [0650] L-glutamine (Sigma G-7513) (2 mM)

    [0651] HEPES buffer (Sigma H-0887) (10 mM) Antibiotic/antimycotic (Sigma A-9909) (1×)

    [0652] MEM non-essential amino acids (Sigma M-7145) (1×)

    [0653] 2-mercaptoethanol (Sigma M-6250) (50 nM)

    L-929 Conditioned Media:

    [0654] L-929 (CCL-1) cells from ATCC were seeded at 4.7×10 W cells in 55 mL of DMEM+10% fetal calf serum in a 75 cm.sup.2 flask. Cells were allowed to grow for THP-1 cells 3 days. On day 3, the supernatant was collected and filtered through a 0.45-μm filter, aliquotted, and frozen at −20° C. The cell-free filtrate was used in the DMEM media for THP-1 infection.

    Infection of THP-1 Cells:

    [0655] On day 0, the media was removed from the cells and replaced with 0.2 ml of antibiotic/antimycotic-free DMEM containing M. tuberculosis HN878 at a MOI of 1 macrophage to 10 bacteria ratio. The tissue culture plates were placed inside closed Ziploc baggies for transport back to the incubator. Once inside the incubator, the baggies were unzipped. The cells were incubated with the bacteria for 2 hours. After infection, the bacteria attached to the outside of the cells were removed, each well was washed once with phosphate buffered saline (PBS), and 2 mL of antibiotic/antimycotic-free complete DMEM media with various drug concentrations was added. To prepare the drug concentrations, serial 2 fold dilutions were performed by adding 10 ml of the previous suspension to 10 ml complete medium plus serum in the next tube. Tissue culture plates were returned to the incubator at 37° C.+5% CO.sub.2 (drugs remained in wells for 3 days). Each drug concentration was tested in triplicate wells.

    [0656] Plating of cell lysates and evaluation of cell viability for THP-1 cells was performed after 2 hours, 1, 2 and 5 days after infection. Tissue culture medium was removed from all wells, and cells were washed twice with 1 ml PBS. Next 1 ml of sterile double distilled water+0.05% Tween-80 was added to each well; cells were left at room temperature for 5-10 min. Cell lysates were serially diluted 1:10 in sterile saline in 24-well tissue culture plates. Diluted cell lysates were plated onto 711/OADC agar through the 1/1,000 dilution step. (Each 24-well TC plate of cells requires four 24-well TC plates for making the serial dilutions, and 24 agar ‘quad’ plates). Plates were incubated at 32° C. for 30 days and colonies were enumerated to determine CFU/ml.

    Results:

    In Vitro THP-1 HN878 Optical Density Results

    [0657] Minimum Inhibitory Concentration (MIC), Reported as the Most Dilute Composition (i.e. the Greatest Dilution Level of the Particular Formulation on the Scale Denoted as 16, 8, 4, 2, 1, 0.5, 0.25, 0.125 μg/ml) which Inhibits the Bacteria

    TABLE-US-00005 MIC MIC MIC MIC (μg/ml) (μg/ml) (μg/ml) (μg/ml) Compound Day 0 Day 1 Day 2 Day 5 Formulation 1 16 16 16 16 (30RESP001FC) Concentrate Formulation 1 16 16 16 16 (30RESP001FD) Dilute Formulation 2 8 8 8 16 (30RESP002FC) Concentrate Formulation 2 16 8 16 16 (30RESP002FD) Dilute Formulation 3 8 8 8 8 (30RESP003FC) Concentrate Formulation 3 8 16 16 16 (30RESP003FD) Dilute Formulation 4 4 4 4 0.125 (30RESP004FC) Concentrate Formulation 4 16 16 0.25 0.25 (30RESP004FD) Dilute

    [0658] The results are shown in FIGS. 24 to 27.

    [0659] FIG. 24: the efficacy of 30RESP001FC and FD (concentrate and dilute) against M. tuberculosis HN878 was evaluated in HIP-1 cells. The efficacy of formulations 30RESP001FC (concentrate) (A), and 30RESP001FD (dilute), (B), after 2 hours (Day 0), 1, 2 and 5 days after infection and treatment with 16 μg/ml (.box-tangle-solidup.), 8 μg/ml (custom-character), 4 μg/ml (⋄), 2 μg/ml (∘), 1 μg/ml (□), 0.5 μg/ml (.diamond-solid.), 0.25 μg/ml (.box-tangle-solidup.), and 0.125 μg/ml (.Math.) were evaluated for intracellular killing of M. tuberculosis HN878 (custom-character) in THP-1 macrophages. In each of the plots in FIG. 24, the .box-tangle-solidup. and custom-character plot lines for treatment with 16 μg/ml and 8 μg/ml, respectively, can be distinguished from the .box-tangle-solidup. and .Math. plot lines for treatment with 0.25 μg/ml and 0.125 μg/ml, respectively, because the treatments with 16 μg/ml and 8 μg/ml are more efficacious. In other words, the plot lines for treatment with 16 μg/ml and 8 μg/ml show significantly lower CFU values than treatment with 0.25 μg/ml and 0.125 μg/ml, particularly at day 5. Similar, the □ plot line for treatment with 1 μg/ml can easily be distinguished from the custom-character plot line for no treatment because the treatment at 1 μg/ml is more efficacious. The custom-character plot line for no treatment has CFU values that rise and remain above 1×10.sup.4 after day 1. custom-character

    [0660] The 30RESP001FC and FD compositions referred to in the above MIC table and in FIG. 24 described as “16 μg/ml” comprise 0.15 M sodium nitrite, 0.05 M mannitol and 0.1 M citric acid/citrate (final molarity post-dilution), with the 8, 4, 2, 1, 0.5, 0.25 and 0.125 μg/ml compositions each respectively a 50% dilution (i.e. halving the concentration) of the previous composition in the said order 16 to 0.125 μg/ml.

    [0661] THP-1 macrophages were infected with M. tuberculosis at a MOI of 1:10 and the numbers of intracellular bacteria were determined using the bacterial colony count method (CFU) immediately after 2 hours (Day 0), 1, 2 and 5 days after infection. Values shown are the mean±SD from one independent experiment. In particular, an increased efficacy relative to the untreated control was present in the treatment with 30RESP001FC and FD (concentrate and dilute) 16 μg/ml, and 8 μg/ml, against M. tuberculosis HN878 (*, p<0.05).

    [0662] FIG. 25: the efficacy of 30RESP002FC and FD (concentrate and dilute) against M. tuberculosis HN878 was evaluated in HP-1 cells. The efficacy of formulations of 30RESP002FC (concentrate) (A), and 30RESP002FD (dilute), (B), after 2 hours, 1, 2 and 5 days after infection and treatment with 16 μg/ml (.box-tangle-solidup.), 8 μg/ml (custom-character), 4 μg/ml (⋄), 2 μg/ml (∘), 1 μg/ml (□), 0.5 μg/ml (.diamond-solid.), 0.25 μg/ml (.box-tangle-solidup.) and 0.125 μg/ml (.Math.) were evaluated for intracellular killing of M. tuberculosis HN878 (custom-character) in THP-1 macrophages. In each of the plots in FIG. 25, the .box-tangle-solidup. and custom-character plot lines for treatment with 16 μg/ml and 8 μg/ml, respectively, can be distinguished from the .box-tangle-solidup. and .Math. plot lines for treatment with 0.25 μg/ml and 0.125 μg/ml, respectively, because the treatments with 16 μg/ml and 8 μg/ml are more efficacious. In other words, the plot lines for treatment with 16 μg/ml and 8 μg/ml show significantly lower CFU values than treatment with 0.25 μg/ml and 0.125 μg/ml, particularly at custom-character day 5. Similar, the □ plot line for treatment with 1 μg/ml can easily be distinguished from the custom-character plot line for no treatment because the treatment at 1 μg/ml is more efficacious. The custom-character plot line for no treatment has CFU values that rise and remain above 1×104 after day 1. custom-character

    [0663] The 30RESP002FC and FD compositions referred to in the above MIC table and in FIG. 25 described as “16 μg/ml” comprise 0.15 M sodium nitrite, 0.05 M lactitol and 0.1 M citric acid/citrate (final molarity post-dilution), with the 8, 4, 2, 1, 0.5, 0.25 and 0.125 μg/ml compositions each respectively a 50% dilution (i.e. halving the concentration) of the previous composition in the said order 16 to 0.125 μg/ml.

    [0664] THP-1 macrophages were infected with M. tuberculosis at a MOI of 1:10 and the numbers of intracellular bacteria were determined using the bacterial colony count method (CFU) immediately after 2 hours, 1, 2 and 5 days after infection. Values shown are the mean SD from one independent experiment. Increased efficacy relative to the untreated control was present in the treatment with 30RESP002FC (concentrate) 16 μg/ml, and 30RESP002FD (dilute) 16 μg/ml and 8 μg/ml, against M. tuberculosis HN878 (*, p<0.05).

    [0665] FIG. 26: the efficacy of 30RESP003FC and FD (concentrate and dilute) against M. tuberculosis HN878 was evaluated in THP-1 cells. The efficacy of 30RESP003FC (concentrate) (A), and 30RESP003FD (dilute), (B), after 2 hours (Day 0), 1, 2 and 5 days after infection and treatment with 16 μg/ml (.box-tangle-solidup.), 8 μg/ml (custom-character), 4 μg/ml (⋄), 2 μg/ml (∘), 1 μg/ml (□), 0.5 μg/ml (.diamond-solid.), 0.25 μg/ml G-38, ART (.box-tangle-solidup.), and 0.125 μg/ml (.Math.) were evaluated for intracellular killing of M. tuberculosis HN878 (custom-character) in THP-1 macrophages. In each of the plots in FIG. 26, the .box-tangle-solidup. and custom-character plot lines for treatment with 16 μg/ml and 8 μg/ml, respectively, can be distinguished from the .box-tangle-solidup. and .Math. plot lines for treatment with 0.25 μg/ml and 0.125 μg/ml, respectively, because the treatments with 16 μg/ml and 8 μg/ml are more efficacious. In other words, the plot lines for treatment with 16 μg/ml and 8 μg/ml show significantly lower CFU values than treatment with 0.25 μg/ml and 0.125 μg/ml, particularly at day 5. Similar, the □ plot line for treatment with 1 μg/ml can easily be distinguished from the custom-character plot line for no treatment because the treatment at 1 μg/ml is more efficacious. The custom-character plot line for no treatment has CFU values that rise and remain above 1×10.sup.4 after day 1.

    [0666] THP-1 macrophages were infected with M. tuberculosis at a MOI of 1:10 and the numbers of intracellular bacteria were determined using the bacterial colony count method (CFU) immediately after 2 hours, 1, 2 and 5 days after infection. Values shown are the mean±SD from one independent experiment. Increased efficacy relative to the untreated control was present in the treatment with 30RESP003FC (concentrate) 16 μg/ml and 8 μg/ml and 30RESP003FD 16 μg/ml, against M. tuberculosis HN878 (*, p<0.05).

    [0667] The 30RESP003FC and FD compositions referred to in the above MIC table and in FIG. 26 described as “16 μg/ml” comprise 0.1 M sodium nitrite, 0.05 M mannitol and 0.1 M citric acid/citrate (final molarity post-dilution), with the 8, 4, 2, 1, 0.5, 0.25 and 0.125 μg/ml compositions each respectively a 50% dilution (i.e. halving the concentration) of the previous composition in the said order 16 to 0.125 μg/ml.

    [0668] FIG. 27: the efficacy of 30RESP004FC and FD (concentrate and dilute) against M. tuberculosis HN878 was evaluated in HP-1 cells. The efficacy of formulations of 30RESP004FC (concentrate) (A), and 30RESP004FD (dilute), (B), after 2 hours (Day 0), 1, 2 and 5 days after infection and treatment with 16 μg/ml (.box-tangle-solidup.), 8 μg/ml (custom-character), 4 μg/ml (⋄), 2 μg/ml (∘), 1 μg/ml (□), 0.5 μg/ml (.diamond-solid.), 0.25 μg/ml (.box-tangle-solidup.) and 0.125 μg/ml (.Math.) were evaluated for intracellular killing of M. tuberculosis HN878 (custom-character) in THP-1 macrophages. In each of the plots in FIG. 27, the .box-tangle-solidup. and custom-character plot lines for treatment with 16 μg/ml and 8 μg/ml, respectively, can be distinguished from the .box-tangle-solidup. and .Math. plot lines for treatment with 0.25 μg/ml and 0.125 μg/ml, respectively, because the treatments with 16 μg/ml and 8 μg/ml are more efficacious. In other words, the plot lines for treatment with 16 μg/ml and 8 μg/ml show significantly lower CFU values than treatment with 0.25 μg/ml and 0.125 μg/ml, particularly at day 5. Similar, the o plot line for treatment with 1 μg/ml can easily be distinguished from the custom-character plot line for no treatment because the treatment at 1 μg/ml is more efficacious. The custom-character plot line for no treatment has CFU values that rise and remain above 1×10.sup.4 after day 1.

    [0669] The 30RESP004FC and FD compositions referred to in the above MIC table and in FIG. 27 described as “16 μg/ml” comprise 0.1 M sodium nitrite, 0.05 M mannitol and 0.1 M ascorbic acid/ascorbate (final molarity post-dilution), with the 8, 4, 2, 1, 0.5, 0.25 and 0.125 μg/ml compositions each respectively a 50% dilution (i.e. halving the concentration) of the previous composition in the said order 16 to 0.125 μg/ml.

    [0670] THP-1 macrophages were infected with M. tuberculosis at a MOI of 1:10 and the numbers of intracellular bacteria were determined using the bacterial colony count method (CFU) immediately after 1, 2 and 5 days after infection. Values shown are the mean±SD from one independent experiment. Increased efficacy relative to the untreated control was present in the treatment with 30RESP004FC (concentrate) 16 μg/ml and 8 μg/ml, against M. tuberculosis HN878 (*, p<0.05).

    [0671] It is concluded that the formulations show in vitro inhibition of M. tuberculosis HN878 at suitable dosages above MIC.

    [0672] It will also be noted that the manner of making the Formulations has an effect on their in vitro antibacterial efficacy against M. tuberculosis HN878 in the tests of Example 6.

    [0673] This is illustrated by comparing the efficacy of the 8 μg/ml concentration of Formulation 1 as between its FC and FD versions (FIG. 24A versus 24B). The efficacy of the FC version increases strongly for at least 5 days after incubation, whereas the efficacy of the FD version increases less strongly for the same time period. This is in contrast to the 16 μg/ml concentration, which shows very similar and good efficacy over the same period, as between the FC and FD versions.

    [0674] Different behaviour is observed with Formulation 2 (FIG. 25A versus 25B). The efficacy of the 16 μg/ml concentration of the FD version increases more strongly than the FC version for the first 2 days after incubation and then does not change, although by 5 days after incubation the efficacy is good in the FD version and very good in the FC. In the case of the 8 μg/ml concentration, the efficacy of the FD version increases strongly to good efficacy for at least 5 days after incubation, whereas the efficacy of the FC version increases less strongly for the same time period.

    [0675] It is thus shown that, at least at higher concentrations, the stage at which the water is added to arrive at the final inhibitory formulation, can materially affect the antibacterial action of the formulation both in terms of the initial antibacterial action and the extent of bacterial killing over 5 days. Generally speaking, although not universally, making the formulation initially as a concentrated pre-mix with the sodium nitrite, polyol and acid ingredients in their desired relative molar proportions but at a higher concentration than desired for use (e.g. at least 3 times, for example at least 5 times more concentrated than desired for use, for example from about 3 to about 80 times more concentrated than desired for use) and only then diluting the concentrate to obtain the formulation for use, leads to a better antibacterial action over the period of 0 to 5 days after incubation.

    Example 7

    Cytotoxicity and Antiviral Activity of Carboxylic Acid-Nitrite-Polyol Solutions Against HIN1 Influenza A Virus

    [0676] Test formulations designated F1C1, F1C2 and F1C3 corresponding respectively to Formulation 30RESP001FC in Example 6, a 10-fold dilution thereof and a 100-fold dilution thereof, were used with oseltamivir solution (1 μM) and virus control to obtain comparative cytotoxicity and HIN1 Influenza A virus killing effect after 24 hours in MDCK cells. The cytotoxicity was assayed by LDH cytotoxicity assay analogously to Example 8. Antimicrobial activity against H1N1 Influenza A virus in MDCK cells was measured at MOI=0.002 (.circle-solid.) and MOI=0.02 (.square-solid.) at a range of dilutions (the horizontal axis is the nitrite molarity) with the cytotoxicity shown in grey, cytotoxicity scale on the right-hand side (cytoxicity at the measured nitrite concentrations up to and including 0.015M was ≤1% of LDH control). Plate photographs were obtained at MOI=0.002 and nitrite concentrations 0.15M, 0.015M and 0.0015M in comparison with oseltamivir (1 μM). The results are shown in FIG. 28. The order of the plates recited in the last-but-one sentence is the same as the order of the plates in the Figure going from left to right (there were two experiments, and the plates of each corresponding experiment are shown one above the other). The far right hand pair of plates, immediately to the right of the oseltamivir pair of plates, is the virus control. The cytotoxicity is shown below each pair of test plates, as the % of LDH control (mean of 3 LDH assays at 24 hours post-infection).

    [0677] The results show that, at a suitable dose of the nitrite/citric acid/polyol formulation there is complete eradication of the virus, and it is clearly superior to oseltamivir. Similar antiviral activity of nitrite/citric acid/polyol formulations has been shown with rhinovirus and respiratory syncytial virus (RSV).

    [0678] These results indicate that therapeutic and prophylactic treatments for respiratory viral infections in human and animal subjects are provided by nitrite/acid/polyol formulations in accordance with the present invention.

    Example 8

    Cytotoxicity and Antiviral Activity of Carboxylic Acid-Nitrite-Polyol Solutions Against Coronavirus SARS-CoV-2

    Materials

    Test Formulation F1 (pH 5.8)

    [0679] Six test concentrations of Formulation 1 (F1), being an aqueous solution of sodium nitrite, citric acid at pH 5.8 and mannitol (a polyol) were prepared by the method described below from stock solutions of 1.5M sodium nitrite, 0.91M citric acid/citrate buffer at pH 5.8, and 0.5M mannitol solution to give the following test compositions:

    Formulation 1 (F1)

    [0680]

    TABLE-US-00006 Concentration Concentration of of sodium citric acid in test Concentration of nitrite in test preparation (M) polyol in test Test agent preparation (M) pH 5.8 preparation (M) F1 test conc 1.5 × 10.sup.−1 M 0.91 × 10.sup.−1 M 5.0 × 10.sup.−2 M 1 (F1C1) mannitol F1 test conc 5.0 × 10.sup.−2 M 0.30 × 10.sup.−1 M 1.5 × 10.sup.−2 M 2 (F1C2) mannitol F1 test conc 1.5 × 10.sup.−2 M 0.91 × 10.sup.−2 M 5.0 × 10.sup.−3 M 3 (F1C3) mannitol F1 test conc 1.5 × 10.sup.−3 M 0.91 × 10.sup.−3 M 5.0 × 10.sup.−4 M 4 (F1C4) mannitol F1 test conc  1.5 × 10−4 M 0.91 × 10.sup.−4 M 5.0 × 10.sup.−5 M 5 (F1C5) mannitol F1 test conc 1.5 × 10.sup.−1 M 0.91 × 10.sup.−1 M 2.5 × 10.sup.−2 M 6 (F1C6) mannitol
    Controls Used with F1

    [0681] A pH 5.8 control formulation was prepared from 0.1 M citric acid+assay buffer+cells.

    [0682] A negative control was assay buffer+cells.

    [0683] Positive controls were chloroquine+cells.

    Test Formulation F2 (pH 5.4)

    [0684] Six test concentrations of Formulation 2 (F2), being an aqueous solution of sodium nitrite, citric acid at pH 5.4 and mannitol (a polyol) were prepared by the method described below from stock solutions of 1.5M sodium nitrite, 0.91M citric acid/citrate buffer at pH 5.4, and 0.5M mannitol solution to give the following test compositions:

    Formulation 2 (F2)

    [0685]

    TABLE-US-00007 Concentration Concentration of of sodium citric acid in test Concentration of nitrite in test preparation (M) polyol in test Test agent preparation (M) pH 5.4 preparation (M) F2 test conc 1.5 × 10.sup.−1 M 0.91 × 10.sup.−1 M 5.0 × 10.sup.−2 M 1 (F2C1) mannitol F2 test conc 5.0 × 10.sup.−2 M 0.30 × 10.sup.−1 M 1.5 × 10.sup.−2 M 2 (F2C2) mannitol F2 test conc 1.5 × 10.sup.−2 M 0.91 × 10.sup.−2 M 5.0 × 10.sup.−3 M 3 (F2C3) mannitol F2 test conc 1.5 × 10.sup.−3 M 0.91 × 10.sup.−3 M 5.0 × 10.sup.−4 M 4 (F2C4) mannitol F2 test conc 1.5 × 10.sup.−4 M 0.91 × 10.sup.−4 M 5.0 × 10.sup.−5 M 5 (F2C5) mannitol F2 test conc 1.5 × 10.sup.−1 M 0.91 × 10.sup.−1 M 2.5 × 10.sup.−2 M 6 (F2C6) mannitol
    Controls Used with F2

    [0686] A pH 5.4 control formulation was prepared from 0.1 M citric acid+assay buffer+cells.

    [0687] A negative control was assay buffer+cells.

    [0688] Positive controls were chloroquine+cells.

    Chemical Reagents

    [0689] Sodium nitrite:

    [0690] Grade: Sodium nitrite extra pure Ph Eur, USP. Sodium nitrite CAS No. 7632-00-0, EC Number 231-555-9., extra pure Ph Eur, USP, from Sigma Aldrich, Product code 1.065441000.

    [0691] Citric acid:

    [0692] Grade: Citric acid anhydrous powder EMPROVE® ESSENTIAL Ph Eur, BP, JP, USP, E 330, FCC, from Sigma Aldrich, Product code 1.002425000.

    [0693] D-Mannitol:

    [0694] Grade: D-Mannitol that meets EP, FCC, USP testing specifications, from Sigma Aldrich, Product code M8429-100G.

    [0695] Chloroquine phosphate:

    [0696] Grade: Pharmaceutical Secondary Standard, from Sigma Aldrich, Product code PHR1258-1G.

    Preparation of the Stock Solutions

    [0697] To prepare the citric acid solution, one adds 90 ml of distilled water to 19.2 g citric acid, followed by 10 ml of 3M sodium hydroxide and then dilute with distilled water to adjust the pH (to 160 ml for pH 5.4 or 190 ml for pH 5.8). In an alternative method, one adds 20 ml of distilled water to 19.2 g citric acid, followed by 1.2 g solid sodium hydroxide and after that adjust the pH with 10M sodium hydroxide and distilled water to 100 ml. The solution is sterilised by syringe filtration using a 0.22 μm filter.

    [0698] To prepare a 1.0 M sodium nitrite solution, 100 mL of distilled water was added to 6.9 g sodium nitrite. To prepare a 1.5 M sodium nitrite solution, 100 mL of distilled water was added to 10.35 g sodium nitrite.

    [0699] When specified, 9.1 g of mannitol was added to give a concentration of 0.5 M. Sterilise solutions by syringe filtration using a 0.22 μm filter.

    Preparation of the Formulations

    [0700] The pH of the buffered citric acid solution is controlled to the desired value, prior to mixing with the nitrite and mannitol solutions. The pH stated for a formulation is the pH of the buffered citric acid solution as made up before mixing with the nitrite and mannitol solutions.

    [0701] One suitable way to make up the formulations is as follows: Sodium nitrite (1.5 M) containing 0.5 M mannitol is added to a mixing vessel, immediately followed by the pH controlled citric acid solution in a 1:1 mix (nitrite+polyol:citric acid). The solutions are mixed by gentle inversion. Once mixed, the mixture is held for 5 minutes in a sealed container (e.g. a 50 ml falcon tube) at ambient temperature. The resulting solution containing 0.75 M nitrite, mannitol 0.25 M, and citric is then diluted 5-fold in assay buffer (1.2-fold concentrated) to give a final test concentration of nitrite 0.15 M, mannitol 0.05 M, and for example citric acid 0.1 M in the assay. Serial dilutions of the 1:1 mix (for example: a mix starting as nitrite 0.75M, mannitol 0.25M, citric acid 0.5M) are made with distilled water and/or the assay buffer medium. All formulation concentrations can be stored at ambient temperature. Solutions are made fresh for each run.

    Additional Controls

    [0702] As additional controls were used S-nitroso-N-acetylpenicillamine (SNAP) at a range of concentrations known to be suitable for its purpose and denoted SNAP50, SNAP100, SNAP200, SNAP300 and SNAP400. SNAP is a known NO donor serving as a positive NO donating control in these tests to provide verification that NO is not cytotoxic in vitro. To control out any potential effect on the assay of the N-acetylpencillamine (NAP) portion of the SNAP molecule, corresponding concentrations of NAP were used as an NO blank control and denoted NAP50, NAP100, NAP200, NAP300 and NAP400.

    Virus

    [0703] SARS-CoV-2 clinical isolate.

    Cell Line

    [0704] Vero E6.

    Assays

    [0705] LDH assay (cytotoxicity):

    [0706] CyQUANT™ LDH Cytotoxicity Assay Kit, Invitrogen; Cat No. C20300 and C20301. Tissue culture infectious dose (TCID50) was determined (virus titration) using cytopathic effect (CPE) scoring as readout.

    [0707] The cytotoxicity of the nitrite formulations (all concentrations), pH 5.8 or pH 5.4 citrate control, negative controls and positive controls (chloroquine, as described by Keyaerts, E, Biochem Biophys Res Commun, 323, 264-268 (2004), the contents of which are incorporated herein by reference) was tested at 2 hr and 24 hr post nitrite/control addition on the Vero E6 cells. LDH release was measured as the readout at the 2 hr and 24 her time points. Each compound/formulation was tested three times per run.

    [0708] SARS-CoV-2 inhibition:

    [0709] At time 0 hr, Vero E6 cells were infected with virus in presence of the formulation or controls and incubated for 1 hour. After this incubation period the inoculum was removed and the cells were washed. Fresh formulation or controls were then added to the washed cells. At 24 hours post infection, Vero E6 cell supernatants were harvested and titrated, and the virus titration was incubated for 6 days prior to readout to determine any virus yield reduction. Separate tests were performed at four MOIs including 3.0 and 0.3, although only those two MOIs were titrated. The readout was by crystal violet (cell monolayer) staining, followed by CPE scoring.

    Results

    [0710] The results are shown in FIGS. 32 to 34.

    [0711] FIG. 32 shows the results of the LDH cytotoxicity assay (combined graph from Runs 1 and 2, using respectively Test Formulations 1 and 2). The data is expressed as mean+standard deviation (SD) of two experiments. SD shown as the grey error bars. The maximum LDH activity (cells+lysis buffer) was set at 100% and all sample results are relative to this value. The LDH positive control was the positive control from the kit. The black bars (2 hour incubation) are the left-hand bar of each pair of bars in each case, and the red bars (24 hour incubation) are the right-hand bar of each pair of bars in each case.

    [0712] FIG. 33 shows the results of the antiviral testing against SARS-CoV-2 of Run 1 at MOI 3.0. In Run 1, one virus yield reduction assay was performed using SARS-CoV-2 at four multiplicities of infection (MOIs), confirmed using back titration of the inoculum virus. For cells inoculated with an MOI of 3, 2.1 log 10 TCID50/ml was found in the virus control well after titration. Reduction of SARS-CoV-2 yield might be observed for some of the conditions tested. After 24 hours of incubation, hardly any virus was detected in the lowest three MOIs (i.e. 0.3, 0.03 and 0.003). Possibly, 24 hours of replication on Vero E6 cells is not sufficient for obtaining high levels of progeny virus. The data is expressed as mean+standard deviation (SD) of two titrations. SD shown as the error bars. The horizontal dotted line level with the chloroquine and cell control log 10 TCID50/ml values is the limit of detection (LOD) of the assay.

    [0713] FIG. 34 shows the results of the antiviral testing against SARS-CoV-2 of Run 2 (a) at MOI 3.0 and (b) at MOI 0.3. The methodology corresponds to the parts of Run 1 at those MOIs, with the exception that the formulations are the Run 2 formulations (Test Formulation 2 at its various concentrations) and incubation was performed for 48 hours rather than 24 hours, in order to increase the level of progeny virus. The data is expressed as mean+standard deviation (SD) of two titrations. SD shown as the error bars. The horizontal dotted line level with the chloroquine and cell control log 10 TCID50/ml values is the limit of detection (LOD) of the assay.

    Discussion

    [0714] The NO generating aqueous formulations are not cytotoxic on the LDH assay (FIG. 32). Particularly at the higher concentrations of nitrite, acid and polyol the in vitro antiviral action against SARS-Cov-2 is impressive and comparable with chloroquine (FIGS. 33 and 34).

    [0715] The NO generating aqueous formulations are effective at a surprisingly high pH. pH 5.4 and 5.8 were tested, but lower pH down to 5.2 or even below would also be expected to have efficacy.

    [0716] Furthermore, the data reveal that organic carboxylic acids (such as citric acid buffered to pH 5.4 or 5.8), in the absence of an NO generating formulation, have a surprising low cytotoxicity and high in vitro antiviral action against SARS-CoV-2 (FIGS. 32 to 34; “citric acid pH 5.8” and “citric acid pH 5.4” bars). The relatively high pH for a carboxylic acid formulation makes such formulations attractive as intrapulmonary active agents as they will be expected to be non-toxic to airway and lung tissue surfaces. Since SARS-Cov-2 belongs to the same coronavirus family as SARS-Cov and there are similarities between the viruses, it is reasonable to predict also that such organic carboxylic acids will show corresponding efficacy against SARS-CoV virus, the coronavirus that is responsible for severe acute respiratory syndrome (SARS), of which there was a well documented outbreak in 2002 and 2003.

    Example 9

    Antiviral Activity of Carboxylic Acid-Nitrite-Polyol Solutions Against Coronavirus SARS-CoV

    [0717] To investigate analogies between the antiviral activity provided by the present invention against SARS-CoV-2 and that provided by the present invention against SARS-CoV, the following experiment was performed.

    [0718] Formulations F1C1, F1C2, F1C3 and F1C4 were tested for antiviral activity against SARS-CoV at MOI 3.0. The methodology was analogous to the antiviral testing described in Example 8. Prior to cell monolayer staining with crystal violet, 2 plates were microscopically checked and scored for cytopathic effect (CPE). A CPE, in the form of cell debris on top of an underlying monolayer, was found to be present in these plates.

    [0719] The results of the two plates, that were microscopically checked, is shown in FIG. 35. Data are a single titration per condition. For the remaining plates, no CPE could be scored after crystal violet staining, due to a too dense cell monolayer. The horizontal dotted line level with the cell control log 10 TCID50/ml value is the limit of detection (LOD) of the assay.

    [0720] As shown in FIG. 35, at least the formulations F1C1 and F1C2 provided good in vitro antiviral activity against SARS-CoV.

    Example 10

    Inhaler for Human Use

    [0721] An embodiment of an inhaler for human use employing a liquid composition according to the present invention is shown schematically in FIGS. 30 and 31.

    [0722] The inhaler is suitably powered by a compressed gas and configured to deliver one dose of entrained droplets of the nitrite/acid/polyol formulation from a reservoir in the inhaler in response to one manual actuation of the inhaler, in generally conventional manner. The subject typically inhales at the same time as actuating the inhaler, as is conventionally done by asthma sufferers when using their inhalers. As shown in FIG. 30, a treatment time of about 3 minutes per dose should be suitable, giving a duration of effect of up to about 2 hours with a suitable dose of the active composition.

    [0723] The airborne droplets travel into the subject's infected lungs, where they contact the infected (e.g. virus-infected) membranes of the lungs. FIG. 31 shows on the right hand side the effect of the present invention in depositing multiple droplets of the aqueous nitric oxide (NO) generating composition (“Aqueous NO”) on the lining of the lungs. FIG. 31 shows on the left hand side the corresponding effect if—instead of the aqueous nitric oxide (NO) generating composition—gaseous nitric oxide is inhaled by the subject (“Inhaled Nitric Oxide”).

    [0724] As shown, the efficacy is likely to be much reduced if Inhaled Nitric Oxide would be used. Not only is a proportion of the inhaled nitric oxide breathed out by the subject before it can pass into the bloodstream through the membrane lining of the lungs, but another proportion of the inhaled nitric oxide is oxidised to toxic nitrogen dioxide (NO.sub.2) by oxygen in the inhaled air. The nitrogen dioxide has an adverse effect on the subject's lungs, in addition to depleting the availability of gaseous nitric oxide for treating the subject.

    [0725] As a result, a more efficient and effective delivery of nitric oxide to the lungs of the patient and into the patient's bloodstream via the lungs is achieved by using a nitrite/acid/polyol formulation in accordance with the present invention.

    CONCLUSION

    [0726] The foregoing broadly describes the present invention without limitation. Variations and modifications as will be readily apparent to those skilled in the art are intended to be included within the scope of the appended claims. To the extent that the laws of any particular jurisdiction in or for which a patent is granted to this invention provide for enforcement of the patent against unauthorised use of technology which is equivalent to the appended claims, the proprietor intends that the patent covers such equivalent technology.

    [0727] Equivalents of the protective scope of the appended claims are also covered by the claims to the extent permitted by applicable law. For example, generally speaking the order of mixing the components or portions of components of the NOx generating reaction described herein is not critical, provided that the NOx generating reaction is not prematurely initiated. Any order of mixing of essential and non-essential components of any combination, kit or composition of the present invention is intended to be covered. If one or more component is used in liquid form, e.g. as solutions, then the effect of the admixture of that component or those components on the concentration of solutes (including but not limited to that component or those components) in the reaction mixture or any component part of the reaction mixture is likely to be different, compared with the case where that one or more component would be used in solid form or in a liquid form at a different volume or concentration. The use of all equivalent concentrations and/or physical forms (solid, liquid, solutions) of components to form the combinations, kits and compositions of the present invention, and all equivalent steps and orders of steps to prepare the said combinations, kits and compositions, even if not described or specifically claimed herein, is within the scope of the present claims to the extent permitted by applicable law.

    [0728] The following statements define aspects or embodiments of the disclosure which are referred to in the claims:

    1. A therapeutic or non-therapeutic method of delivering nitric oxide, optionally other oxides of nitrogen and/or optionally precursors thereof to a human or animal subject via the nose, mouth, respiratory tract or lung(s) of the subject, which comprises:
    (A) administering to the subject via the nose, mouth, respiratory tract or lung(s) of the subject a combination or composition for generating nitric oxide, optionally other oxides of nitrogen and/or optionally precursors thereof by reaction of one or more nitrite salt with a proton source, the combination or composition comprising: [0729] (i) one or more nitrite salt; [0730] (ii) a proton source comprising one or more acid selected from organic carboxylic acids and organic non-carboxylic reducing acids; and [0731] (iii) one or more organic polyol;
    characterised by one or more of the following: [0732] (a) the one or more organic polyol is present in a reaction output enhancing amount, wherein the enhancement of the output of the reaction is in comparison with a reaction performed under the same conditions but without the one or more organic polyol; [0733] (b) the proton source is not solely a hydrogel comprising pendant carboxylic acid groups covalently bonded to a three-dimensional polymeric matrix; [0734] (c) the one or more organic polyol is not solely glycerol; [0735] (d) the one or more organic polyol is not solely glycerol when one or more viscosity increasing agent is used; [0736] (e) the one or more organic polyol is not solely glycerol when one or more plasticizer is used; [0737] (f) the one or more organic polyol is not solely polyvinyl alcohol; [0738] (g) the one or more organic polyol is not solely polyvinyl alcohol when one or more viscosity increasing agent is used; [0739] (h) any one or more of (b) to (g) above, wherein the words “is not solely” are replaced by “does not comprise”; [0740] (i) the one or more organic polyol is not solely propylene glycol, polyethylene glycol, glycerin monostearate (glyceryl stearate), trihydroxyethylamine, D-pantothenyl alcohol, panthenol, panthenol in combination with inositol, butanediol, butenediol, butynediol, pentanediol, hexanediol, octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, dibutylene glycol, butane-1,2,3-triol, butane-1,2,4-triol, hexane-1,2,6-triol, hexylene glycol, caprylyl glycol, glycols other than those listed here, hydroquinone, butylated hydroquinone, 1-thioglycerol, erythorbate, ethylhexylglycerin, any combination thereof, or any combination of any of the above with glycerol and/or polyvinyl alcohol; [0741] (j) the one or more organic polyol does not comprise propylene glycol, polyethylene glycol, glycerin monostearate (glyceryl stearate), trihydroxyethylamine, D-pantothenyl alcohol, panthenol, panthenol in combination with inositol, butanediol, butenediol, butynediol, pentanediol, hexanediol, octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, dibutylene glycol, butane-1,2,3-triol, butane-1,2,4-triol, hexane-1,2,6-triol, hexylene glycol, caprylyl glycol, glycols other than those listed here, hydroquinone, butylated hydroquinone, 1-thioglycerol, erythorbate, ethylhexylglycerin, any combination thereof, or any combination of any of the above with glycerol and/or polyvinyl alcohol;
    or
    (B) administering to the subject via the nose, mouth, respiratory tract or lung(s) of the subject nitric oxide, optionally other oxides of nitrogen and/or optionally precursors thereof, which has been prepared by a method comprising reacting: [0742] (i) one or more nitrite salt with [0743] (ii) a proton source comprising one or more acid selected from organic carboxylic acids and organic non-carboxylic reducing acids under reaction conditions suitable to generate nitric oxide, optionally other oxides of nitrogen and/or optionally precursors thereof, wherein the reaction is performed in the presence of [0744] (iii) one or more organic polyol; [0745] characterised by one or more of the following: [0746] (a) the one or more organic polyol is present in a reaction output enhancing amount; [0747] (b) the proton source is not solely a hydrogel comprising pendant carboxylic acid groups covalently bonded to a three-dimensional polymeric matrix; [0748] (c) the one or more organic polyol is not solely glycerol; [0749] (d) the one or more organic polyol is not solely glycerol when one or more viscosity increasing agent is used; [0750] (e) the one or more organic polyol is not solely glycerol when one or more plasticizer is used; [0751] (f) the one or more organic polyol is not solely polyvinyl alcohol; [0752] (g) the one or more organic polyol is not solely polyvinyl alcohol when one or more viscosity increasing agent is used; [0753] (h) any one or more of (b) to (g) above, wherein the words “is not solely” are replaced by “does not comprise”; [0754] (i) the one or more organic polyol is not solely propylene glycol, polyethylene glycol, glycerin monostearate (glyceryl stearate), trihydroxyethylamine, D-pantothenyl alcohol, panthenol, panthenol in combination with inositol, butanediol, butenediol, butynediol, pentanediol, hexanediol, octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, dibutylene glycol, butane-1,2,3-triol, butane-1,2,4-triol, hexane-1,2,6-triol, hexylene glycol, caprylyl glycol, glycols other than those listed here, hydroquinone, butylated hydroquinone, 1-thioglycerol, erythorbate, ethylhexylglycerin, any combination thereof, or any combination of any of the above with glycerol and/or polyvinyl alcohol; [0755] (j) the one or more organic polyol does not comprise propylene glycol, polyethylene glycol, glycerin monostearate (glyceryl stearate), trihydroxyethylamine, D-pantothenyl alcohol, panthenol, panthenol in combination with inositol, butanediol, butenediol, butynediol, pentanediol, hexanediol, octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, dibutylene glycol, butane-1,2,3-triol, butane-1,2,4-triol, hexane-1,2,6-triol, hexylene glycol, caprylyl glycol, glycols other than those listed here, hydroquinone, butylated hydroquinone, 1-thioglycerol, erythorbate, ethylhexylglycerin, any combination thereof, or any combination of any of the above with glycerol and/or polyvinyl alcohol.
    2. A method according to statement 1, wherein the proton source comprises a hydrogel comprising pendant carboxylic acid groups covalently bonded to a three-dimensional polymeric matrix, the combination or kit comprises two or more separate compositions, and the one or more polyol is not present in the separate compositions in direct contact or admixture with the hydrogel.
    3. A method according to statement 1(A) or statement 2, wherein the combination or composition consists essentially of the components (i), (ii) and (iii) and optionally water and/or a pH buffer.
    4. A method according to statement 1(A) or statement 2, wherein the combination or composition consists of the components (i), (ii) and (iii) and optionally water and/or a pH buffer and/or one or more additional component in an amount of less than about 20% by weight or volume of the combination or of the composition.
    5. A method according to any one of the preceding statements, which is a method of treating a microbial infection in a subject in need thereof, for example a human subject or other mammalian subject, for example a bacterial, viral, fungal, microparasitical infection or any combination thereof.
    6. A method according to any one of statements 1 to 4, which is a method of vasodilation performed on a subject, for example a human subject or other mammalian subject.
    7. A method according to any one of statements 1 to 4, which is an antimicrobial method, for example to reduce the number of microbes, for example bacteria, viruses, fungal cells and/or microparasites, at a locus of the subject, to prevent proliferation thereof, or to restrict the rate of proliferation thereof.
    8. A method according to statement 5, wherein the microbial infection is on the skin of the subject, for example mucosae, or in an internal space of the subject, for example in the nose, mouth, respiratory tract or lungs of the subject, or the lining of the subject's lung pleura.
    9. A modification of the antimicrobial method according to statement 7, wherein in the combination or composition administered to the subject the initial pH of an aqueous solution of the proton source including any desired buffer before other components of the NOx generating reaction mixture are present that will affect the pH, or the pH or the reaction mixture at the start of the reaction with the one or more nitrite salt, is in the range of 5 to 8, and the one or more polyol is optional and may be omitted.
    10. A method according to any one of statements 1 to 9, which is performed in association with a surgical method or a method which involves both therapy and surgery.
    11. A substance or composition, being:
    (A) a combination or composition for use in therapy and/or surgery for generating nitric oxide, optionally other oxides of nitrogen and/or optionally precursors thereof by reaction of one or more nitrite salt with a proton source, the combination or composition comprising: [0756] (i) one or more nitrite salt; [0757] (ii) a proton source comprising one or more acid selected from organic carboxylic acids and organic non-carboxylic reducing acids; and [0758] (iii) one or more organic polyol;
    characterised by one or more of the following: [0759] (a) the one or more organic polyol is present in a reaction output enhancing amount, wherein the enhancement of the output of the reaction is in comparison with a reaction performed under the same conditions but without the one or more organic polyol; [0760] (b) the proton source is not solely a hydrogel comprising pendant carboxylic acid groups covalently bonded to a three-dimensional polymeric matrix; [0761] (c) the one or more organic polyol is not solely glycerol; [0762] (d) the one or more organic polyol is not solely glycerol when one or more viscosity increasing agent is used; [0763] (e) the one or more organic polyol is not solely glycerol when one or more plasticizer is used; [0764] (f) the one or more organic polyol is not solely polyvinyl alcohol; [0765] (g) the one or more organic polyol is not solely polyvinyl alcohol when one or more viscosity increasing agent is used; [0766] (h) any one or more of (b) to (g) above, wherein the words “is not solely” are replaced by “does not comprise”; [0767] (i) the one or more organic polyol is not solely propylene glycol, polyethylene glycol, glycerin monostearate (glyceryl stearate), trihydroxyethylamine, D-pantothenyl alcohol, panthenol, panthenol in combination with inositol, butanediol, butenediol, butynediol, pentanediol, hexanediol, octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, dibutylene glycol, butane-1,2,3-triol, butane-1,2,4-triol, hexane-1,2,6-triol, hexylene glycol, caprylyl glycol, glycols other than those listed here, hydroquinone, butylated hydroquinone, 1-thioglycerol, erythorbate, ethylhexylglycerin, any combination thereof, or any combination of any of the above with glycerol and/or polyvinyl alcohol; [0768] (j) the one or more organic polyol does not comprise propylene glycol, polyethylene glycol, glycerin monostearate (glyceryl stearate), trihydroxyethylamine, D-pantothenyl alcohol, panthenol, panthenol in combination with inositol, butanediol, butenediol, butynediol, pentanediol, hexanediol, octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, dibutylene glycol, butane-1,2,3-triol, butane-1,2,4-triol, hexane-1,2,6-triol, hexylene glycol, caprylyl glycol, glycols other than those listed here, hydroquinone, butylated hydroquinone, 1-thioglycerol, erythorbate, ethylhexylglycerin, any combination thereof, or any combination of any of the above with glycerol and/or polyvinyl alcohol; [0769] wherein the therapy and/or surgery comprises administering the combination or composition to the subject via the nose, mouth, respiratory tract or lung(s) of the subject;
    or
    (B) nitric oxide, optionally other oxides of nitrogen and/or optionally precursors thereof, for use in therapy and/or surgery which has been prepared by a method comprising reacting: [0770] (i) one or more nitrite salt with [0771] (ii) a proton source comprising one or more acid selected from organic carboxylic acids and organic non-carboxylic reducing acids under reaction conditions suitable to generate nitric oxide, optionally other oxides of nitrogen and/or optionally precursors thereof, wherein the reaction is performed in the presence of [0772] (iii) one or more organic polyol;
    characterised by one or more of the following: [0773] (a) the one or more organic polyol is present in a reaction output enhancing amount; [0774] (b) the proton source is not solely a hydrogel comprising pendant carboxylic acid groups covalently bonded to a three-dimensional polymeric matrix; [0775] (c) the one or more organic polyol is not solely glycerol; [0776] (d) the one or more organic polyol is not solely glycerol when one or more viscosity increasing agent is used; [0777] (e) the one or more organic polyol is not solely glycerol when one or more plasticizer is used; [0778] (f) the one or more organic polyol is not solely polyvinyl alcohol; [0779] (g) the one or more organic polyol is not solely polyvinyl alcohol when one or more viscosity increasing agent is used; [0780] (h) any one or more of (b) to (g) above, wherein the words “is not solely” are replaced by “does not comprise”; [0781] (i) the one or more organic polyol is not solely propylene glycol, polyethylene glycol, glycerin monostearate (glyceryl stearate), trihydroxyethylamine, D-pantothenyl alcohol, panthenol, panthenol in combination with inositol, butanediol, butenediol, butynediol, pentanediol, hexanediol, octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, dibutylene glycol, butane-1,2,3-triol, butane-1,2,4-triol, hexane-1,2,6-triol, hexylene glycol, caprylyl glycol, glycols other than those listed here, hydroquinone, butylated hydroquinone, 1-thioglycerol, erythorbate, ethylhexylglycerin, any combination thereof, or any combination of any of the above with glycerol and/or polyvinyl alcohol; [0782] (j) the one or more organic polyol does not comprise propylene glycol, polyethylene glycol, glycerin monostearate (glyceryl stearate), trihydroxyethylamine, D-pantothenyl alcohol, panthenol, panthenol in combination with inositol, butanediol, butenediol, butynediol, pentanediol, hexanediol, octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, dibutylene glycol, butane-1,2,3-triol, butane-1,2,4-triol, hexane-1,2,6-triol, hexylene glycol, caprylyl glycol, glycols other than those listed here, hydroquinone, butylated hydroquinone, 1-thioglycerol, erythorbate, ethylhexylglycerin, any combination thereof, or any combination of any of the above with glycerol and/or polyvinyl alcohol;
    wherein the therapy and/or surgery comprises administering the nitric oxide, optionally other oxides of nitrogen and/or optionally precursors thereof to the subject via the nose, mouth, respiratory tract or lung(s) of the subject;
    or
    (C) a combination or composition for administration to the nose, mouth, respiratory tract or lung(s) of a subject for generating nitric oxide, optionally other oxides of nitrogen and/or optionally precursors thereof by reaction of one or more nitrite salt with a proton source, the combination or composition comprising: [0783] (i) one or more nitrite salt; [0784] (ii) a proton source comprising one or more acid selected from organic carboxylic acids and organic non-carboxylic reducing acids; and [0785] (iii) one or more organic polyol;
    characterised by one or more of the following: [0786] (a) the one or more organic polyol is present in a reaction output enhancing amount, wherein the enhancement of the output of the reaction is in comparison with a reaction performed under the same conditions but without the one or more organic polyol; [0787] (b) the proton source is not solely a hydrogel comprising pendant carboxylic acid groups covalently bonded to a three-dimensional polymeric matrix; [0788] (c) the one or more organic polyol is not solely glycerol; [0789] (d) the one or more organic polyol is not solely glycerol when one or more viscosity increasing agent is used; [0790] (e) the one or more organic polyol is not solely glycerol when one or more plasticizer is used; [0791] (f) the one or more organic polyol is not solely polyvinyl alcohol; [0792] (g) the one or more organic polyol is not solely polyvinyl alcohol when one or more viscosity increasing agent is used; [0793] (h) any one or more of (b) to (g) above, wherein the words “is not solely” are replaced by “does not comprise”; [0794] (i) the one or more organic polyol is not solely propylene glycol, polyethylene glycol, glycerin monostearate (glyceryl stearate), trihydroxyethylamine, D-pantothenyl alcohol, panthenol, panthenol in combination with inositol, butanediol, butenediol, butynediol, pentanediol, hexanediol, octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, dibutylene glycol, butane-1,2,3-triol, butane-1,2,4-triol, hexane-1,2,6-triol, hexylene glycol, caprylyl glycol, glycols other than those listed here, hydroquinone, butylated hydroquinone, 1-thioglycerol, erythorbate, ethylhexylglycerin, any combination thereof, or any combination of any of the above with glycerol and/or polyvinyl alcohol; [0795] (j) the one or more organic polyol does not comprise propylene glycol, polyethylene glycol, glycerin monostearate (glyceryl stearate), trihydroxyethylamine, D-pantothenyl alcohol, panthenol, panthenol in combination with inositol, butanediol, butenediol, butynediol, pentanediol, hexanediol, octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, dibutylene glycol, butane-1,2,3-triol, butane-1,2,4-triol, hexane-1,2,6-triol, hexylene glycol, caprylyl glycol, glycols other than those listed here, hydroquinone, butylated hydroquinone, 1-thioglycerol, erythorbate, ethylhexylglycerin, any combination thereof, or any combination of any of the above with glycerol and/or polyvinyl alcohol.
    12. A substance or composition according to statement 11, wherein the therapy and/or surgery comprises a method according to any one of statements 1 to 10.
    13. A method, or a substance or composition, according to any one of the preceding statements, wherein the one or more nitrite salt is selected from LiNO.sub.2, NaNO.sub.2, KNO.sub.2, RbNO.sub.2, CsNO.sub.2, FrNO.sub.2, AgNO.sub.2, Be(NO.sub.2).sub.2, Mg(NO.sub.2).sub.2, Ca(NO.sub.2).sub.2, Sr(NO.sub.2).sub.2, Mn(NO.sub.2).sub.2, Ba(NO.sub.2).sub.2, Ra(NO.sub.2).sub.2 and any mixture thereof.
    14. A method, or a substance or composition, according to statement 13, wherein the one or more nitrite salt is NaNO.sub.2, KNO.sub.2, or a mixture thereof.
    15. A method, or a substance or composition, according to any one of the preceding statements, wherein the one or more nitrite salt or any component of the NOx generating reaction system that contains the one or more nitrite salt is present in dry form, for example in particulate dry form.
    16. A method, or a substance or composition, according to any one of statements 1 to 14, wherein the one or more nitrite salt or any component of the NOx generating reaction system that contains the one or more nitrite salt is present in solution in an aqueous carrier, for example an aqueous liquid or gel.
    17. A method, or a substance or composition, according to statement 16, wherein the molarity of nitrite ion in the solution is in the range of about 0.001 M to about 5 M.
    18. A method, or a substance or composition, according to any one of the preceding statements, wherein the pH of the one or more nitrite salt or any component of the NOx generating reaction system that contains the one or more nitrite salt is buffered, preferably to a pH of about 6 to about 9.
    19. A method, or a substance or composition, according to any one of the preceding statements, wherein the one or more organic carboxylic acid of the proton source is selected from: salicylic acid, acetyl salicylic acid, acetic acid, citric acid, glycolic acid, mandelic acid, tartaric acid, lactic acid, maleic acid, malic acid, benzoic acid, formic acid, propionic acid, α-hydroxypropanoic acid, β-hydroxypropanoic acid, β-hydroxybutyric acid, β-hydroxy-β-butyric acid, naphthoic acid, oleic acid, palmitic acid, pamoic (emboic) acid, stearic acid, malonic acid, succinic acid, fumaric acid, glucoheptonic acid, glucuronic acid, lactobioic acid, cinnamic acid, pyruvic acid, orotic acid, glyceric acid, glycyrrhizic acid, sorbic acid, hyaluronic acid, alginic acid, oxalic acid, salts thereof, and combinations thereof; one or more polymeric or polymerised carboxylic acid such as, for example, polyacrylic acid, polymethacrylic acid, a copolymer of acrylic acid and methacrylic acid, polylactic acid, polyglycolic acid, or a copolymer of lactic and glycolic acid; one or more acid hydrogel containing pendant —COOH groups covalently attached to a polymer molecule forming a three-dimensional polymeric matrix of the hydrogel; partial or full esters and partial or full salts thereof provided that those can serve as a proton source; and any mixture or combination thereof.
    20. A method, or a substance or composition, according to statement 19, wherein the one or more carboxylic acid is selected from citric acid, salts thereof, and combinations thereof.
    21. A method, or a substance or composition, according to any one of the preceding statements, wherein the one or more non-carboxylic reducing acid of the proton source is selected from ascorbic acid; ascorbate palmitic acid (ascorbyl palmitate); ascorbate derivatives such as 3-O-ethyl ascorbic acid, other 3-alkyl ascorbic acids, 6-O-octanoyl ascorbic acid, 6-O-dodecanoyl ascorbic acid, 6-O-tetradecanoyl ascorbic acid, 6-O-octadecanoyl ascorbic acid and 6-O-dodecanedioyl ascorbic acid; acidic reductones such as, for example, reductic acid; erythorbic acid; oxalic acid; salts thereof; and combinations thereof.
    22. A method, or a substance or composition, according to statement 21, wherein the organic non-carboxylic reducing acid is ascorbic acid or a salt thereof.
    23. A method, or a substance or composition, according to any one of the preceding statements, wherein the proton source, or a component part thereof, or any component of the NOx generating reaction system that contains the proton source, is present in dry form, for example in particulate dry form.
    24. A method, or a substance or composition, according to any one of statements 1 to 22, wherein the proton source, or a component part thereof, or any component of the NOx generating reaction system that contains the proton source, is present in solution in an aqueous carrier, for example an aqueous liquid or gel.
    25. A method, or a substance or composition, according to statement 24, wherein the molarity of proton source in the solution is in the range of about 0.001 M to about 5 M.
    26. A method, or a substance or composition, according to any one of the preceding statements, wherein the pH of the proton source is buffered, preferably to a pH of about 3 to about 9, for example about 4 to about 8, for example about 5 to about 8.
    27. A method, or a substance or composition, according to any one of the preceding statements, wherein the one or more organic polyol is selected from sugar alcohols having 4, 5, 6, 7, 8, 9, 10, 11 or 12 carbon atoms, for example alditols having 4, 5, 6, 7, 8, 9, 10, 11 or 12 carbon atoms.
    28. A method, or a substance or composition, according to any one of the preceding statements, wherein the one or more organic polyol is selected from erythritol, threitol, arabitol, xylitol, ribitol, mannitol, sorbitol, galactitol, fucitol, iditol, inositol, volemitol, isomalt, maltitol, lactitol, maltotriitol, maltotetraitol, polyglycitol, glycerol and any combination thereof.
    29. A method, or a substance or composition, according to statement 27 or statement 28, wherein the one or more organic polyol is selected from arabitol, xylitol, mannitol, sorbitol and any combination thereof.
    30. A method, or a substance or composition, according to any one of the preceding statements, wherein the one or more organic polyol or any component of the NOx generating reaction system that contains the one or more organic polyol is present in dry form, for example in particulate dry form.
    31. A method, or a substance or composition, according to any one of statements 1 to 29, wherein the one or more organic polyol or any component of the NOx generating reaction system that contains the one or more organic polyol is present in solution in an aqueous carrier, for example an aqueous liquid or gel.
    32. A method, or a substance or composition, according to statement 31, wherein the molarity of total one or more organic polyol the solution is in the range of about 0.001 M to about 5 M.
    33. A method, or a substance or composition, according to any one of the preceding statements, wherein: [0796] (a) the total molar concentration of any one or more organic polyol in the polyol component or in the reaction solution at or before the start of the NOx generating reaction is between about 0.05 and about 3, for example between about 0.1 and about 2, for example between about 0.25 and about 1.5 times the total molar concentration of the nitrite ion in the nitrite component or in the reaction solution; or [0797] (b) the total molar concentration of any one or more organic polyol in the polyol component or in the reaction solution at or before the start of the NOx generating reaction is between about 0.05 and about 3, for example between about 0.1 and about 2, for example between about 0.25 and about 1.5 times the total molar concentration of the proton source in the proton source component or in the reaction solution.
    34. A method, or a substance or composition, according to any one of the preceding statements, wherein the combination or composition for generating nitric oxide, optionally other oxides of nitrogen and/or optionally precursors thereof by reaction of one or more nitrite salt with a proton source further comprises one or more additional components selected from diluents, carriers, excipients, sweetening agents, taste-masking agents, thickening agents, viscosifying agents, wetting agents, film-forming agents, lubricants, binders, emulsifiers, solubilising agents, stabilising agents, colourants, odourants, salts, coating agents, antioxidants, pharmaceutically active agents, preservatives, and any combination thereof.
    35. A kit for use in a method, or for use in preparing and optionally delivering a substance or composition, according to any one of the preceding statements, wherein in addition to the component chemical substances of types (i), (ii) and, when present, (iii), the kit comprises at least one of the following: containers for holding the components before use; at least one device or other means for mixing the components, dispensing the reaction mixture and/or the evolved gas, and controlling the said mixing and dispensing, instructions for use, and directions to where instructions for use may be found, for example on-line instructions for use.
    36. A dispenser for use in a method according to any one of statements 1 to 10 and 13 to 34, comprising: the component chemical substances of types (i), (ii) and, when present, (iii) as defined in the said statement; at least one container for holding the components before use; at least one device or other means for controlled mixing of the components and dispensing the reaction mixture, one or more components thereof and/or the evolved gas out of the dispenser and direct it to a target.
    37. A dispenser according to statement 36, wherein the dispenser is adapted for a repeated similar action of dispensing the reaction mixture, one or more components thereof, a carrier that comprises the reaction mixture, a carrier that comprises one or more components of the reaction mixture, and/or the evolved gas.
    38. A dispenser according to statement 36 or statement 37, wherein the dispenser comprises a pump or a propellant system to carry the composition comprising the NO generating reaction mixture, one or more of the components thereof, or the evolved gases out of the dispenser and direct it to a target.
    39. A dispenser according to any one of statements 36 to 38, wherein the dispenser is adapted to direct the reaction mixture, one or more components thereof, a carrier that comprises the reaction mixture, a carrier that comprises one or more components of the reaction mixture, and/or the evolved gas to the nose, mouth, respiratory tract or lungs of a human or animal subject.
    40. A nitric oxide dispenser, comprising a pressurised cylinder of nitric oxide gas and a delivery device connectable to the pressurised cylinder and adapted to deliver the nitric oxide gas from the pressurised cylinder to the nose, mouth, respiratory tract or lungs of a human or animal subject, wherein the nitric oxide is nitric oxide generated by a method comprising reacting one or more nitrite salt with a proton source comprising one or more acid selected from organic carboxylic acids and organic non-carboxylic reducing acids under reaction conditions suitable to generate nitric oxide, optionally other oxides of nitrogen and/or optionally precursors thereof, wherein the reaction is performed in the presence of one or more organic polyol;
    characterised by one or more of the following: [0798] (a) the one or more organic polyol is present in a reaction output enhancing amount; [0799] (b) the proton source is not solely a hydrogel comprising pendant carboxylic acid groups covalently bonded to a three-dimensional polymeric matrix; [0800] (c) the one or more organic polyol is not solely glycerol; [0801] (d) the one or more organic polyol is not solely glycerol when one or more viscosity increasing agent is used; [0802] (e) the one or more organic polyol is not solely glycerol when one or more plasticizer is used; [0803] (f) the one or more organic polyol is not solely polyvinyl alcohol; [0804] (g) the one or more organic polyol is not solely polyvinyl alcohol when one or more viscosity increasing agent is used; [0805] (h) any one or more of (b) to (g) above, wherein the words “is not solely” are replaced by “does not comprise”; [0806] (i) the one or more organic polyol is not solely propylene glycol, polyethylene glycol, glycerin monostearate (glyceryl stearate), trihydroxyethylamine, D-pantothenyl alcohol, panthenol, panthenol in combination with inositol, butanediol, butenediol, butynediol, pentanediol, hexanediol, octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, dibutylene glycol, butane-1,2,3-triol, butane-1,2,4-triol, hexane-1,2,6-triol, hexylene glycol, caprylyl glycol, glycols other than those listed here, hydroquinone, butylated hydroquinone, 1-thioglycerol, erythorbate, ethylhexylglycerin, any combination thereof, or any combination of any of the above with glycerol and/or polyvinyl alcohol; [0807] (j) the one or more organic polyol does not comprise propylene glycol, polyethylene glycol, glycerin monostearate (glyceryl stearate), trihydroxyethylamine, D-pantothenyl alcohol, panthenol, panthenol in combination with inositol, butanediol, butenediol, butynediol, pentanediol, hexanediol, octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, dibutylene glycol, butane-1,2,3-triol, butane-1,2,4-triol, hexane-1,2,6-triol, hexylene glycol, caprylyl glycol, glycols other than those listed here, hydroquinone, butylated hydroquinone, 1-thioglycerol, erythorbate, ethylhexylglycerin, any combination thereof, or any combination of any of the above with glycerol and/or polyvinyl alcohol.
    41. Nitric oxide, optionally other oxides of nitrogen and/or optionally precursors thereof, when dispensed using a dispenser according to any one of statements 38 to 40.
    42. A method, or a substance or composition, or a kit, or a dispenser, or nitric oxide, optionally other oxides of nitrogen and/or optionally precursors thereof, when dispensed using the dispenser, according to any one of the preceding statements, wherein: [0808] the one or more nitrite salt comprises (for example, includes or consists essentially of or consists only of) one or more alkali metal or alkaline earth metal nitrite salt, for example: sodium nitrite; potassium nitrite; or any combination thereof; [0809] the proton source comprises (for example, includes or consists essentially of or consists only of) ascorbic acid or ascorbic acid/ascorbate buffer; citric acid or citric acid/citrate buffer; or any combination of two or more thereof; [0810] the molecules of the said ascorbic acid or ascorbic acid/ascorbate buffer, citric acid or citric acid/citrate buffer, or any combination of two or more thereof, are not covalently bonded to a polymer or macromolecule; [0811] the one or more organic polyol comprises (for example, includes or consists essentially of or consists only of) a straight-chain sugar alcohol or alditol having from 4 to 12 carbon atoms and from 4 to 12 OH groups per molecule; for example sorbitol; mannitol; arabitol; xylitol; or any combination of two or more thereof; [0812] the total molar concentration of any one or more organic polyol in the polyol component or in the reaction solution at or before the start of the NOx generating reaction is between 0.05 and 3 times the total molar concentration of the nitrite ion; [0813] the total molar concentration of any one or more organic polyol in the polyol component or in the reaction solution at or before the start of the NOx generating reaction is between 0.05 and 3 times the total molar concentration of the proton source in the proton source component or in the reaction solution; [0814] the pH of the proton source before, particularly immediately before, initiation of the NOx generating reaction is in the range 3.0 to 9.0 for applications which do not involve contact between the reaction mixture and cells or animal (including human) skin (including mucosae), organs or other tissue; [0815] the pH of the proton source before, particularly immediately before, initiation of the NOx generating reaction is in the range 4.0 to 8.0 for applications which involve contact between the reaction mixture and cells or animal (including human) skin (including mucosae), organs or other tissue; [0816] the pH of the proton source before, particularly immediately before, initiation of the NO generating reaction is in the range 5.0 to 8.0 for applications which involve contact between the reaction mixture and the nose, mouth, respiratory tract or lungs of an animal (including human) subject; [0817] in addition to M. tuberculosis, the microbe targeted is selected from bacterial species in the list Actinomyces, Bacillus, Bartonella, Bordetalla, Borrelia, Brucella, Campylobacter, Chlamydia, Chlamydophila, Clostridium, Corynebacterium, Enterococcus, Escherichia, Francisella, Haemophilus, Heliobacter, Legionella, Leptospira, Listeria, Mycobacterium, Mycoplasma, Neisseria, Pseudomonas, Rickettsia, Salmonella, Shigella, Staphylococcus, Streptococcus, Treponema, Ureaplasma, Vibrio, Yersinia genera or any combination thereof; fungal species in the list Aspergillus, Blastomyces, Candida, Coccidioides, Cryptococcus, Hisoplamsa, Murcomycetes, Pneumocystis, Sporothrix, Talaromyces, or any combination thereof; viruses in the list influenza viruses, parainfluenza viruses, adenoviruses, noroviruses, rotaviruses, rhinoviruses, coronaviruses, respiratory syncytial virus (RSV), astroviruses, hepatic viruses or any combination thereof; and protozoa in the list Sarcodina, Mastigophora, Ciliophora, Sporozoa or any combination thereof; for example, SARS-CoV or SARS-CoV-2, and non-tuberculosis mycobacteria including Mycobacterium abscessus, Pseudomonas aeruginosa including antibiotic-resistant strains thereof.
    43. A method, or a substance or composition, or a kit, or a dispenser, or nitric oxide, optionally other oxides of nitrogen and/or optionally precursors thereof when dispensed using a dispenser, according to any one of the preceding statements, wherein the one or more organic polyol, when present, does not include (i.e. excludes) a reductant.