TOPICAL ANTIMICROBIAL FORMULAS WITH MONOVALENTEN COPPER IONS AND SYSTEMS FOR THE GENERATING MONOVALENTEN COPPER IONS

Description

Field of the Invention

[0001] The present invention relates to antimicrobial formulations. More particularly, the invention relates to monovalent copper-containing and / or monovalent copper-generating products for use as dressings for healing of chronic wounds and burns, and particularly for use in preventing wound infections and infections in various implants as well as a bandage comprising the antimicrobial formulation.Background of the Invention

[0002] Copper (Cu) is an essential trace element for most living organisms. However, in high concentration it can exert biocidal effect in various mechanisms, most of them are yet not fully understood (Grass Get al., Appl. Environ. Microbiol., 2011; 77(5):1541-1547). First mentioned in an Egyptian papyrus dated back to 2600-2200 BC, the antimicrobial properties of copper have been well recognized and documented throughout history (Dollwet H. et al., Trace Elements Med. 1985; 2(2):80-87).

[0003] Over recent decades, copper has regained scientific interest due to its possible applications in the healthcare setting. One of the most common and established medical applications of copper is the addition of ionized copper-silver in hospital water systems as an effective method to control Hospital-acquired Legionella infection (Stout J. E. et al., Infect. Control Hosp. Epidemiol., 2003; 24(8):563-568). Various studies have demonstrated the effective impact of copper biocidal surfaces in reducing the spread of various bacteria, yeasts and viruses, a conclusion that was later on supported in clinical trials.

[0004] The mechanisms behind copper toxicity are still a subject of ongoing research, but a number of contributing factors have already been established. A major factor is the ability to act as a catalyst for oxidative damage to tissues through cyclic redox reactions, alternating between Cu(I) and Cu(II). The reactive oxygen species generated in these reactions directly damage essential cell components like nucleic acids, proteins, and lipids. Intracellular free copper ions also contribute to cell death through protein inactivation. The significance of the effect of copper on DNA degradation is still controversial, with different mechanisms of toxicity observed in different types of microorganisms. In several studies that involved enterococci DNA degradation as a result of copper ionic species and the generation of superoxides was a key factor in cell death process (Warnes SL et al., Appl. Environ. Microbiol., 2010 Aug; 76(16): 5390-401; Warnes SL et al., Appl. Environ. Microbiol., 2011 Sep; 77 (17): 6049-6059). In contrast, other studies that explored copper toxic effects on Gram-negative bacteria such as Escherichia coli and yeasts suggested that depolarization of the cytoplasmic membrane is the main target, while DNA degradation occurs only after cell death (Macomber L. et al., J. Bacteriol. 2007, Mar;189(5):1616-26; Quaranta D. et al., Appl. Environ. Microbiol., 2011, Jan; 77(2):416-26).

[0005] The two most common ions formed by copper are the +1 (cuprous) and +2 (cupric) ions. The cuprous ion is the chemically more active and less stable of the two oxidation states, and is easily oxidized in an aqueous environment. However, it is possible to maintain high concentration of cuprous ions in aqueous environment by adding reagents which form a very stable complex with the cuprous ion, such as acetonitrile (CH 3 CN) (Parker A. J. et al., Journal of Solution Chemistry, November 1981, Volume 10, Issue 11, pp 757-774) or benzoic acid (C 6 H 5 COOH) (Saphier M. et al., J. Chem. Soc., Dalton Ttans., 1845-1849, 1999). Keeping the environment anaerobic also helps in stabilizing the cuprous form.

[0006] Currently, Ag (I) (Silver) ions are used to treat wound infection in burn victims as well as in chronic wounds. The present invention demonstrates that the use of Cu (I) ions, rather than Ag (I) ions or Cu (II) and metallic copper, is more efficient in eliminating Bacteria (such as Escherichia coli, Staphylococcus aureus) and yeast (such as Saccharomyces cerevisiae).

[0007] US 2016 / 220728 A1 relates to antimicrobial compositions comprising surface functionalized particles of low water solubility inorganic copper salts, or such copper salts infused into porous particles, their preparation, combinations of these particles with other additives and antimicrobial materials, and application of the compositions for wound care.

[0008] US 2014 / 271757 A1 relates to antimicrobial compositions comprising surface functionalized particles of low water solubility inorganic copper salts, or such copper salts or silver salts infused into porous particles, their preparation, combinations of these copper-based particles with other antimicrobial materials, application of the compositions and methods of preparation.

[0009] US 5 458 906 A relates to antibacterial fibers are disclosed which are produced by immersing fibers in a solution containing a copper compound, as monovalent copper cations, and at the same time or subsequently treating the fibers in a solution containing carbonate and / or borate anions.

[0010] Davies et al. The Reaction between copper(II) Ions and L-Ascorbic Acid in Chloride Media. Inorg. Chim. Acta 1988, 146 (1), 59- 63, studied the reaction of copper(II) with L-ascorbic acid in the presence of chloride ions.Summary of the Invention

[0011] The present invention relates to an antimicrobial formulation comprising a monovalent copper ions (cuprous, Cu 1+< ) generating system, wherein the monovalent copper is produced in situ by reduction of divalent copper ions (cupric, Cu 2+< ) selected from copper sulphate, CuSO 4 , copper chloride, CuCl 2 , copper acetate, Cu(CH 3 COO) 2 , and copper gluconate, C 12 H 22 CuO 14 in the presence of a reducing agent; wherein the divalent copper ions source is a salt or complex which is able to release divalent copper ions into the reaction mixture that is an aqueous solution; wherein the reducing agent is selected from ascorbyl palmitate, ascorbic acid, or other salts thereof and metallic copper and a stabilizing ligand wherein the stabilizing ligand is acetonitrile; ascorbyl palmitate (0.1-15%) or ascorbic acid (0.1-15%) for use as dressings for healing of chronic wounds and burns.

[0012] Another embodiment of the present invention relates to the antimicrobial formulation as described above, for use in preventing wound infections.

[0013] A further embodiment of the present invention relates to the antimicrobial formulation as described above, for use in preventing infections in implants and medical / surgical devices.

[0014] A further embodiment of the present invention relates to the antimicrobial formulation as described above, for use in the treatment of skin infections, such as acne and herpes.

[0015] A further embodiment of the present invention relates to the antimicrobial formulation as described above, for use in skin healing.

[0016] According to the present invention, the stabilizing ligand is acetonitrile; ascorbyl palmitate (0.1-15%) or ascorbic acid (0.1-15%).

[0017] According to the present invention, the reducing agent is selected from ascorbyl palmitate, ascorbic acid or other salts thereof and metallic copper.A further embodiment of the present invention provides a bandage comprising the formulation as described above for use in the treatment of anaerobic infections.

[0018] A specific embodiment of the present invention provides a bandage as described above, wherein the external side of the bandage is sealed against penetration of oxygen from the external environment.Brief Description of the Drawings

[0019] Figure 1 shows the viable cell count of E. coli bacteria (Δlog cfu / ml) over time of treating with Cu 1+< , Cu 2+< , Ag 1+< and control groups (no copper and metal copper alone), using syringes technique. Figure 2 shows the viable cell count of E. coli bacteria (Δlog cfu / ml) over time of treating with Cu 1+< , 8 mM Ag 1+< and 16 mM Ag 1+< , using syringes technique. Figure 3 shows the viable cell count of Staphylococcus aureus bacteria (Δlog cfu / ml) over time of treating with Cu 1+< , Cu 2+< and control groups (no copper and metal copper alone), using syringes technique. Figure 4 shows the viable cell count of Saccharomyces cerevisiae yeast (Δlog cfu / ml) over time of treating with Cu 1+< , Cu 2+< and control groups (no copper and metal copper alone), using syringes technique. Figure 5 shows the results of a disc diffusion antibiotic sensitivity test (as radiuses in mm of sterile zones on agar), exemplifying the advantage of the Cu 1+< ions over Ag 1+< and Cu 2+< . Figure 6 shows a schematic representation of the structure of an adhesive bandage comprising the cuprous ions as an antimicrobial agent for improved healing for chronic non-healing wounds and burns. Figure 7 shows the results of a disc diffusion antibiotic sensitivity test (as radiuses in mm of sterile zones on agar) for the antibacterial activity of emulsifying base ointments (example 1). Figure 8 shows the results of stability test of emulsifying base ointments (example 1) using a disc diffusion antibiotic sensitivity test (as radiuses in mm of sterile zones on agar) at preparation time and after 6 months' storage at room temperature and at 37 °C. Figure 9 shows the results of a disc diffusion antibiotic sensitivity test (as radiuses in mm of sterile zones on agar) for the antibacterial activity of absorption base ointments (example 2). Figure 10 shows the results of stability test of absorption base ointments (example 2), using a disc diffusion antibiotic sensitivity test (as radiuses in mm of sterile zones on agar) at preparation time and in after 2 months storage at room temperature and at 37 °C. Detailed Description

[0020] The present invention exemplifies the potency of Cu 1+< over Cu 2+< copper ion in eliminating various microorganisms. Cu 1+< was found to be more potent antimicrobial agent than Ag +< , which is a popular antimicrobial ion used in many modern types of wound dressings. Therefore, the present invention provides a more potent antimicrobial dressings comprising Cu 1+< as an active agent. The results of this study are consistent when using two different methods of bacterial growth and, more importantly, when using two different chemical reactions for the in situ production of Cu 1+< - one with metallic copper and acetonitrile and the other with ascorbic acid. Both materials are non-toxic agents.Definitions

[0021] The term "microbial" refers herein to any kind of bacteria, yeast, fungus and virus.

[0022] The term "metallic copper" refers herein to copper in its metallic form, namely, oxidation state 0. The metallic copper may be, but not limited to, in the form of powder, wires, net, sheets, nano particles or any other known form.

[0023] The term "stabilizing ligand" refers herein to a non-toxic ligand which is able to stabilize monovalent copper ions. Such a ligand is acetonitrile; ascorbyl palmitate (0.1-15%) or ascorbic acid (0.1-15%).

[0024] The term "reducing agent" refers herein to a non-toxic agent which is able to reduce divalent copper ions into monovalent copper ions. Such an agent might be metals, such as aluminum, iron and copper, and biological reducing agents (antioxidants) such as ascorbic acid, beta-carotene and folic acid. The reducing agent is is selected from ascorbyl palmitate, ascorbic acid, or other salts thereof and metallic copper.

[0025] The term "divalent copper ions source" refers herein to a non-toxic compound, salt or complex which is able to release divalent copper ions into the reaction mixture. Such a source is selected from copper sulphate, CuSO 4 , copper chloride, CuCl 2 , copper acetate, Cu(CH 3 COO) 2 , and copper gluconate, C 12 H 22 CuO 14 .

[0026] The term "filling agent" refers herein to a structural agent such as used in the cosmetics and in medical formulations. Examples of such an agent are poly(vinyl alcohol) (PVA), stearyl alcohol, sodium lauryl sulfate, glycerol, lanolin, Vaseline or combinations thereof.

[0027] The term "emollient" refers herein to supple, waxlike, lubricating, thickening agent that prevents water loss and has a softening and soothing effect on skin. Examples of emollients are ingredients like plant oils, mineral oil, petrolatum, and fatty acids. More specifically, emollient may refer to Vaseline, lanolin, triglycerides, benzoates, myristates, palmitates, and stearates.

[0028] The term "vehicle" refers herein to any carrier or inert medium used as a solvent (or diluent) in which the medicinally active agent is formulated and or administered.

[0029] Three groups of filling agents are possible: 1. Cream (Example 1) - emulsion of water (e.g., 60-80% buffer (0.1M PBS), oil (20-40% oil component, e.g., mineral or vegetable oil) and emulsifier 2% (e.g. carboxymethyl cellulose, lanolin) 2. Ointment (Example 2) - semi-solid preparations of hydrocarbons (petrolatum, mineral oil, paraffin, synthetic hydrocarbons) 3. Paste - mixture of powder and ointment (e.g., zinc oxide 20% paste)

[0030] All possible groups have to contain copper source, reducing agent and / or stabilizing ligand.Materials and methods

[0031] Syringes technique: Bacteria cells were incubated at room temperature under anaerobic conditions in LB Bruce growth substance syringes. To ensure anaerobic conditions, Argon gas (UHP) was bubbled through a sterile filter into a syringe filled with a growth substance. Cu 1+< was formed in situ, the process was started with deaerating the aqueous solutions containing a mixture of CuSO 4 as the source for Cu 2+< ions, metallic copper and Acetonitrile as a stabilizing ligand, prior to microorganisms insertion, according to the following reaction: K 1 %CH 3 CN = 1 * 10 2

[0032] One must notice that each Cu 2+< results in two Cu 1+< ions.

[0033] 0.1 M acetonitrile (0.5 % V / V), which according to preliminary tests was shown to be the minimal effective concentration, was use as a stabilizing ligand.

[0034] Reference bacteria were incubated under the same condition in a growth substance containing: Metallic copper (4X2X0.1cm), Acetonitrile, CuSO 4 or AgNO 3

[0035] Bacteria count was measured at time intervals using a series of dilutions, and colonies count on LB Agar was incubated at 37 0< C.

[0036] Petri dish technique: Bacteria were incubated at 37 0< C in Petri dish with LB Agar containing 20 mM ascorbic acid and 0.05 - 3.5 mM CuSO 4 covered by oil, to prevent air oxygen penetration. As control groups, bacteria were incubated under the same conditions without ascorbic acid, or without CuSO 4 . In this series of experiments ascorbic acid acted as the reducing agent according to the following reaction:         2Cu 2+< + ascorbic acid →2Cu +< + dehydro ascorbic acid     (2)

[0037] The viability of bacteria was detected by the presence or absence of colonies.Disc diffusion antibiotic sensitivity test:

[0038] 1. Introduction: The antibacterial effect was measured by an agar disk diffusion method. Escherichia coli strain MG1655 was used as a model organism. Whatman's 6 mm disks were used. The incubation of Petri dishes (with disks) was done in aerobic conditions, at 37 °C. After 24 h incubation, the radiuses of sterile zones on agar were measured. 2. Experimental procedure: 2.1 Preparation of bacterial suspension 100 µL of bacterial suspension (containing 10 4< - 10 5< bacterial cells per plate) was used for testing. Cells of E. coli MG1655 were grown overnight as a starter on LB (Luria broth) media at 37°C with a shaker. After 12-18 hhours incubation, 100 µL suspension were added to 9.9 mL of fresh LB media. Bacterial cells designated for testing were grown in fresh LB at 37 °C with a shaker for 2-3 h to final OD (600 nm) 0.2 - 0.4. This cell suspension was diluted by a factor of 100 using 0.9% NaCl, and 100 µL of the diluted suspension was distributed on agar surface before adding a disk. 2.2 Preparation of Petri dishes LB agar was prepared according to a standard procedure, autoclaved and stored afterwards up to 3 h at 55 °C. The needed substances (like ascorbic acid) were added into agar before pouring into dishes. 15 ml agar was added to each 90 mm Petri dish. Dishes were dried for at least 1 h in a biosafety cabinet by sterile air flow. 2.3 Formulation application To the preliminary dried dishes (a described in 2.2) a freshly prepared bacterial culture was added (as described in 2.1). Immediately after absorption of the suspension into the agar, a disk was placed at the center of the dish. In case where metallic copper was tested, it was placed first in the form of a small circular wire at the dish center and pressed into the agar, and covered by a disk afterwards. 10 µL of a Cu 2+< solution was placed on the disk. 2.4 Measurement of the sterile zone size All dishes after 24 h incubation (as described in 2.1) were photographed and the images are analyzed. The absolute size of the sterile zones was estimated in comparison with the disk size (6 mm). The results were presented as sterile area in mm 2< (Figure 5 and Table 2) or as radiuses in mm (Figures 7-10) of the sterile zones on agar. Results

[0039] The vitality of Escherichia coli, Staphylococcus aureus (bacteria) and Saccharomyces cerevisiae (yeast) was tested in anaerobic conditions using syringe technique and Petri dish technique.

[0040] The following four different conditions were tested: A- a syringe containing metallic copper with Cu 2+< reacting in the presence of CH 3 CN to give 2 Cu 1+< prior to bacteria insertion; B- a syringe containing Cu 2+< only; C- a syringe containing metallic copper; and D- a reference syringe without copper. The effect of Cu 1+< , Cu 2+< , Cu 0< on gram negative bacteria (Ecoli)

[0041] Table 1 summarizes 16 various experiments with different concentrations of Cu 1+< , Cu 2+< , and control groups (no copper and metal copper alone). Cu 1+< is stable only under the conditions presented in column A.

[0042] Table 2 compares the antibacterial efficacy of Cu 1+< with Ag 1+< and Cu 2+< , tested on E. coli by disk diffusion method. It is shown that exposure to Cu 1+< provides more than 10 times improvement in the biocidal effect. Table 2IonEstimate of the sterile area beyond the disk (mm 2< )Cu 1+< 359.3Ag 1+< 27.1Cu 2+< 25.9 Minimal inhibitory concentration (MIC) of univalent and divalent copper ions on E.coli.

[0043] The MIC of Cu 1+< and Cu 2+< was measured by using four syringes with decreasing concentration of the copper ions from 8 to 2 mM. Table 3Cu 1+< Cu 1+< Cu 1+< Cu 1+< Cu +2< Cu +2< Cu +2< Cu 2+< positive control without coppernegative control without E. coli2 mM4 mM6 mM8 mM2 mM4 mM6 mM8 mM++107--+++++-++-

[0044] Table 3 shows the presence ("++" represents a fully covered plate, estimated as 2x10 7< cfu / ml; "+" represents partially covered plate but still uncountable, estimated as 1x10 4< cfu / ml; when a number is given, it indicates the number of colonies on the plate) or absence (-) of E. coli colonies after 24h incubation with decreasing concentrations of copper ions and 0.5 % (v / v) of acetonitrile. MIC of Cu 1+< found to be around 4mM where the MIC of Cu 2+< was between 6mM and 8mM.Petri dish technique:

[0045] The experiment was repeated using a different reducing agent (ascorbic acid instead of metal copper with acetonitrile) and different technique of growing bacteria on Petri dishes with LB agar. The ascorbic acid embedded in the agar reduces copper as was shown in Equation 2. Table 4Ascorbic acid20mM20mM20mM0mM0mMCuSO 4 0mM0.01mM0.05mM3.0mM4.0mMVitality of E.coli MG 1655++++-++-

[0046] Table 4 demonstrates the ascorbic acid and copper ion concentration effect on E. coli vitality 24h after incubation. The bactericidal effect of reduced copper ions (Cu 1+< ) was eight times higher than that of Cu 2+< .Kinetics of bactericidal effect of copper and silver ions on E. coli

[0047] Because of the chemical similarity of copper and silver as well as their clinical use as antibacterial agents, their antibacterial effect over time was compared. The survival of test bacteria in each syringe was sampled in time intervals of 1, 20, 40 and 85 hours from inoculation. Time-kill curve was constructed by plotting the viable cell count of bacteria (Δlog10 cfu / ml) over time (Figure 1).

[0048] The syringe with Cu 1+< ions demonstrated a significant reduction of the initial bacteria inoculums by 7 log cfu / ml after 1 h of incubation in anaerobic environment. In the next sample, 20 hours after inoculation, no viable bacteria cell was found at all. A more gradual decline in the viable cell count along time was observed in the Cu +2< syringe, and it should be noted that even after 85 hours, live bacteria still remained in the syringe (1 log cfu / ml). A similar pattern of decline was seen in the syringe that contained silver ions (Ag +< ), but after 85 hours no viable cells were found. As expected, none of the negative control syringes showed toxic effect on bacteria survival during the experiment timeline.

[0049] Figure 2 shows the result of 1h incubation of E. coli with 8mM Cu 1+< compared to 8mM and 16mM of Ag +< . That experiment demonstrates that even when doubling the Ag +< concentration Cu 1+< is a more potent antibacterial agent.The effect Cu 1+< , Cu 2+< , Cu 0< on gram positive bacteria (Staphylococcus aureus)

[0050] The MIC of Cu 1+< is measured by using Petri dishes with LB agar. The ascorbic acid embedded in the agar reduces copper as was shown in Equation 2. Table 5Control without S. aureusControl without copper(I) and ascorbic acidCopper(I) 0.3 mM with Ascorbic acid 20 mMCopper(I) 0.1 mM with Ascorbic acid 20 mMCopper(I) 0.05 mM with Ascorbic acid 20 mM-++-45++

[0051] Table 5 demonstrates the ascorbic acid and copper ion concentration effect on S. aureus vitality 24h after incubation.

[0052] Figure 3 demonstrates the growth kinetics of gram positive Staphylococcus aureus in anaerobic conditions using the syringe technique in the presence of Cu 1+< , Cu 2+< , metallic Cu and control. It is noticeable that Cu 2+< had very little bacteriostatic effect while exposure to Cu 1+< caused depletion of bacterial count within 1h of incubation. When comparing with Figure 2 it seems that the difference between the effect of Cu 1+< and Cu 2+< is more pronounced in gram (+) bacteria than in gram(-).The effect Cu 1+< , Cu 2+< , Cu 0< on gram positive yeast (Saccharomyces cerevisiae)

[0053] Similar effect is found with Saccharomyces cerevisiae (Figure 4), however, the yeasts were more susceptible to Cu 2+< than both bacteria studied.Disc diffusion antibiotic sensitivity test

[0054] The results of the disc diffusion antibiotic sensitivity test are presented in Figure 5. Cu 1+< yields a sterile area of 359.3 mm 2< , much larger than the area resulted from the Ag +< disc (27.1 mm 2< ) and the Cu +2< disc (25.9 mm 2< ). The results are another indication for the superiority of the monovalent copper ions as an antimicrobial agent in comparison with the traditional silver ions and divalent copper ions.Use of Cu 1+< as an antimicrobial dressing

[0055] The improved antimicrobial effect of monovalent copper ions, especially under anaerobic conditions, is demonstrated above. Anaerobic bacteria play a major role in the pathogenesis of chronic ulcers as well as major burns. Therefore, monovalent coppers ions can be used as an active agent in topical antimicrobial formulations.

[0056] One embodiment of the invention relates to an adhesive bandage comprising: copper wires; and ointment comprising divalent copper ions source, reducing agent, filling and glycerol.

[0057] A Schematic example of such an adhesive bandage is presented in Figure 6.

[0058] This invention has further the potential to be impregnated into surgical sutures and into medical / surgical implants and devices and reduce the rate of implant / device related infections. It further has the potential to reduce the formation of biofilm around implants thus enabling other antibiotics to reach the implant site in case of infection, as well as reducing the chance of other biofilm related morbidity such as capsular contracture.Examples Example 1- Emulsifying base ointments that generate Cu(I) ions Preparation

[0059] The ointment having in situ Cu(I) generating mechanism was made by mixing of ointment base (emollient and vehicle) with copper(II) gluconate, ascorbyl palmitate and copper powder. The mixing can be done with mortar and pestle for massive quantities (20-100 g) of ointment, and with the help of a clock glass and plastic spatula for a small amount (1-4 g) of ointment. The proportion of copper(II) gluconate and ascorbyl palmitate was used as for absorption ointment (1.4:1), as described in Example 2 below, and 2% w.t. of copper in the powder form was added to each sample. The following ointments with different mass concentrations of copper(II) gluconate were made: 0.625% w.t. (E-0), 1.25% w.t. (E-1), 2.5% w.t. (E-2), 5% w.t. (E-10) and 15% w.t. (see Table 6). Antibacterial effect

[0060] Figure 7 shows a strong correlation between the copper (II) gluconate concentration in the emulsifying base and its antibacterial effect. The minimal recommended concentration of copper (II) gluconate was determined as 1.25% w / w.Stability test of emulsifying base ointments formulations

[0061] Measurements that were done after storage are divided into two groups: "room conditions", referring to measurement of ointment sample, which was stored at room temperature; and "37 °C" referring to measurement of ointment sample, which was stored in the incubator at 37 °C.

[0062] All Petri dishes that were used for antimicrobial efficacy tests were triplicated for calculating of standard deviation. The samples were stored in a closed container.

[0063] Figure 8 presents inhibition radius of bacterial growth at beginning and in after 6 months of E-5 emulsifying base ointment sample.Example 2- Absorption base ointments that generate Cu(I) ions Preparation

[0064] For preparation of 100 gram of absorption base, 35 g of vaseline and 35 g of lanolin were heated in a chemical glass on water bath at 70° C till melted together into a yellowish transparent liquid and then 30 g of glycerol 80%w.t was added. The mixture was withdrawn from the water bath and cooled by stirring with a spatula until completely congealed.

[0065] Ascorbyl palmitate and copper(II) gluconate may be added directly to the prepared base with a mortar and pestle for massive quantities (20-100 g) of ointment and with the help of a clock glass and plastic spatula for a small amount (1-4 g) of ointment. However, for better dispersion of the ascorbyl palmitate and the copper(II) gluconate, they were mixed with glycerol 80%w.t. and then added to the mixture of vaseline and lanolin (1:1 ratio). Metal copper in the powder form was added in amount of 2%w.t. of ointment. Copper(II) gluconate and ascorbyl palmitate were used in 1.4:1 mole ratio (while the stoichiometric ratio is 1:1 ) because of low stability of ascorbyl palmitate and necessity of prevention of the copper powder oxidation. Four ointments with different mass concentrations of copper(II) gluconate of 10%w.t. (A-10), 11%w.t. (A-11), 13%w.t. (A-13) and 15w.t. (A-15) were used. Composition of these ointments is presented in Table 7. Antibacterial effect

[0066] According to Figure 9, the relation between inhibition radius of bacterial growth and copper (II) gluconate mass concentration is similar to the one in Figure 7. Again, the more copper (II) gluconate was in the emulsifying base, the inhibition radius was larger. However, in the case of the emulsifying base formulation, a lower Cu(ll) concentration is required for inhibition, and therefore it is termed as "quick release" ointment. The absorption base ointment is termed as "slow release" ointment.Stability test of absorption base ointments formulations

[0067] Measurements that were done after storage are divided into two groups: "room conditions", referring to measurement of ointment sample, which was stored at room temperature; and "37 °C" referring to measurement of ointment sample, which was stored in the incubator at 37 °C.

[0068] All Petri dishes that were used for antimicrobial efficacy tests were triplicated for calculating of standard deviation. The samples were stored in a closed container.

[0069] Figure 10 presents inhibition radius of bacterial growth at beginning and in after 2 months of A-10 absorption base ointment sample.

Claims

1. An antimicrobial formulation comprising a monovalent copper ions (cuprous, Cu1+) generating system, wherein the monovalent copper is produced in situ by reduction of divalent copper ions (cupric, Cu2+) selected from copper sulphate, CuSO4, copper chloride, CuCl2, copper acetate, Cu(CH3COO)2, and copper gluconate, C12H22CuO14 in the presence of a reducing agent; wherein the divalent copper ions source is a salt or complex which is able to release divalent copper ions into the reaction mixture that is an aqueous solution; wherein the reducing agent is selected from ascorbyl palmitate, ascorbic acid, or other salts thereof and metallic copper and and a stabilizing ligand wherein the stabilizing ligand is acetonitrile; ascorbyl palmitate (0.1-15%) or ascorbic acid (0.1-15%)for use as dressings for healing of chronic wounds and burns.

2. An antimicrobial formulation comprising a monovalent copper ions (cuprous, Cu1+) generating system, wherein the monovalent copper is produced in situ by reduction of divalent copper ions (cupric, Cu2+) selected from copper sulphate, CuSO4, copper chloride, CuCl2, copper acetate, Cu(CH3COO)2, and copper gluconate, C12H22CuO14 in the presence of a reducing agent; wherein the divalent copper ions source is a salt or complex which is able to release divalent copper ions into the reaction mixture that is an aqueous solution; wherein the reducing agent is selected from ascorbyl palmitate, ascorbic acid, or other salts thereof and metallic copper and and a stabilizing ligand wherein the stabilizing ligand is acetonitrile; ascorbyl palmitate (0.1-15%) or ascorbic acid (0.1-15%)for use in preventing wound infections.

3. An antimicrobial formulation comprising a monovalent copper ions (cuprous, Cu1+) generating system, wherein the monovalent copper is produced in situ by reduction of divalent copper ions (cupric, Cu2+) selected from copper sulphate, CuSO4, copper chloride, CuCl2, copper acetate, Cu(CH3COO)2, and copper gluconate, C12H22CuO14 in the presence of a reducing agent; wherein the divalent copper ions source is a salt or complex which is able to release divalent copper ions into the reaction mixture that is an aqueous solution; wherein the reducing agent is selected from ascorbyl palmitate, ascorbic acid, or other salts thereof and metallic copper and and a stabilizing ligand wherein the stabilizing ligand is acetonitrile; ascorbyl palmitate (0.1-15%) or ascorbic acid (0.1-15%)for use in preventing infections in implants and medical / surgical devices.

4. An antimicrobial formulation comprising a monovalent copper ions (cuprous, Cu1+) generating system, wherein the monovalent copper is produced in situ by reduction of divalent copper ions (cupric, Cu2+) selected from copper sulphate, CuSO4, copper chloride, CuCl2, copper acetate, Cu(CH3COO)2, and copper gluconate, C12H22CuO14 in the presence of a reducing agent; wherein the divalent copper ions source is a salt or complex which is able to release divalent copper ions into the reaction mixture that is an aqueous solution; wherein the reducing agent is selected from ascorbyl palmitate, ascorbic acid, or other salts thereof and metallic copper and and a stabilizing ligand wherein the stabilizing ligand is acetonitrile; ascorbyl palmitate (0.1-15%) or ascorbic acid (0.1-15%)for use in the treatment of skin infections, such as acne and herpes.

5. An antimicrobial formulation comprising a monovalent copper ions (cuprous, Cu1+) generating system, wherein the monovalent copper is produced in situ by reduction of divalent copper ions (cupric, Cu2+) selected from copper sulphate, CuSO4, copper chloride, CuCl2, copper acetate, Cu(CH3COO)2, and copper gluconate, C12H22CuO14 in the presence of a reducing agent; wherein the divalent copper ions source is a salt or complex which is able to release divalent copper ions into the reaction mixture that is an aqueous solution; wherein the reducing agent is selected from ascorbyl palmitate, ascorbic acid, or other salts thereof and metallic copper and and a stabilizing ligand wherein the stabilizing ligand is acetonitrile; ascorbyl palmitate (0.1-15%) or ascorbic acid (0.1-15%)for use in skin healing.

6. A bandage comprising an antimicrobial formulation comprising a monovalent copper ions (cuprous, Cu1+) generating system, wherein the monovalent copper is produced in situ by reduction of divalent copper ions (cupric, Cu2+) selected from copper sulphate, CuSO4, copper chloride, CuCl2, copper acetate, Cu(CH3COO)2, and copper gluconate, C12H22CuO14 in the presence of a reducing agent; wherein the divalent copper ions source is a salt or complex which is able to release divalent copper ions into the reaction mixture that is an aqueous solution; wherein the reducing agent is selected from ascorbyl palmitate, ascorbic acid, or other salts thereof and metallic copper and and a stabilizing ligand wherein the stabilizing ligand is acetonitrile; ascorbyl palmitate (0.1-15%) or ascorbic acid (0.1-15%)for use in the treatment of anaerobic infections.

7. A bandage for use according to claim 6, wherein the external side of the bandage is sealed against penetration of oxygen from the external environment.