This invention relates to matrices, such as wound dressings, and methods for making such matrices.

Honey has been used for treatment of microbial infections since ancient times. In recent years there has been a resurgence of interest in the therapeutic efficacy of honey, particularly in the area of wound healing. Clinical trials have shown that honey is an effective broad-spectrum antimicrobial agent which is effective against common wound-infecting organisms, such as Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and Escherichia coli, and is effective against antibiotic-resistant strains of bacteria. As a natural product, honey also offers an attractive alternative to drug-based treatments.

Many different types of honey have antimicrobial activity. This activity is attributed largely to osmolarity, pH, hydrogen peroxide production and the presence of phytochemical components.

The applicant has appreciated that the antimicrobial effects of honey can be greatly enhanced and controlled by adding glucose oxidase to honey, and that compositions comprising honey and added glucose oxidase are applicable in the treatment of a number of infections, and notably in the treatment of infections caused by biofilms (see WO 2015/166197, WO 2016/083798 and WO 2016/124926).

However, because honey is a natural product, its composition can vary greatly depending on its source. For example, the difference in antimicrobial potency among honeys can be more than one hundred-fold, depending on the geographical, seasonal and botanical source of the honey, as well as the harvesting, processing and storage conditions. Consequently, the antimicrobial efficacy may also vary depending on the type of honey used. Furthermore, honey may also contain other components, such as allergens e.g. trace amounts of pollen, which may cause adverse reactions when applied to certain subjects and make it unsuitable for certain pharmaceutical applications.

Honey may also require processing such that it is in a suitable form for application to subjects, which can add cost and complexity to the production process. Such processing may include creaming or pasteurisation.

Consequently, there is a desire to provide improved compositions which provide enhanced antimicrobial efficacy compared to honey, and which also overcome some of honey’s disadvantages. There is also a desire to provide compositions with improved stability and which have the ability to provide antimicrobial activity over an extended period of time. In some situations, such as in the treatment of topical wounds, it may be advantageous to administer an antimicrobial composition with a dressing. Although honey-based compositions, and synthetic compositions similar to honey, can be co-administered with a dressing, they can be sticky and difficult to handle, and may be incompatible with certain types of dressing materials.

The applicant has devised matrices that can be used as wound dressings, which may address at least some of these disadvantages. The applicant has also devised methods of making such matrices.

The present invention is directed to an antimicrobial matrix that comprises an enzyme that is able to convert a substrate to release hydrogen peroxide; and a substrate for the enzyme. The matrix may comprise a matrix material which is coated with, or on which is deposited, the enzyme and the substrate. In other words, the matrix material may be coated with a composition comprising the enzyme and the substrate. The matrix preferably does not comprise sufficient free water to allow the enzyme to convert the substrate. Most preferably, the matrix is substantially free of water.

Such matrices may provide certain technical advantages. If the matrix is substantially dry it may not have a sticky or wet feel, and may thus be more convenient to handle. Furthermore, a dry matrix with substantially no water present means that hydrogen peroxide production is minimised. Hydrogen peroxide production may thus only take place once water is added to the matrix, for example if the matrix is exposed to wound exudate.

The matrix material may be any matrix material suitable for use in a wound dressing. For example, it may include a gauze, tulle, bandage or foam. The matrix material is preferably a fabric.

If the matrix is substantially free of water, matrix materials, such as gel-forming matrix materials may be advantageously employed. If water-containing compositions are coated on gel-forming matrix materials, the matrix material may absorb water from the composition and begin to form a gel, even before applying the material to a wound. This may decrease the exudate-absorbing capabilities of the matrix.

Advantageously, the matrix material may thus comprise a gel-forming matrix material. The gel forming matrix material may comprise alginate or hydrofibres. These types of dressings may undergo gelation with exudate absorption. This may promote a moist wound-healing environment, autolytic debridement, and atraumatic removal, and may minimise lateral wicking. Gel-forming fibres typically include derivatised cellulose. The structure below is a b-glucose monomer of cellulose.

Cellulose derivatives include cellulose in which one or more hydroxyl groups have been substituted with other functional groups.

For example, X, Y and/or Z may be a group other than H. For example, the cellulose derivative may be carboxymethyl cellulose (e.g. sodium carboxymethyl cellulose) or cellulose ethyl sulfonate. Other cellulose derivatives include ester-based derivatives such as cellulose acetate, cellulose acetate phthalate, cellulose acetate butyrate, cellulose acetate trimellitate, hydroxypropyl methylcellulose phthalate; or ether-based derivatives such as methylcellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and hydroxypropyl methylcellulose. Matrix materials suitable for use in matrices of the invention may include materials capable of forming hydrogels. Gel-forming dressing materials based on cellulose derivatives are commercially available, such as AQUACEL® Dressings from ConvaTec®, which uses Hydrofibre® technology utilising sodium carboxymethyl cellulose.

Alternatively, the matrix material may comprise collagen. Collagen plays a key role in wound healing. It may attract cells, such as fibroblasts and keratinocytes, to the wound, which may encourage debridement, angiogenesis, and re-epithelialization. In addition, collagen provides a natural scaffold or substrate for new tissue growth. Collagen dressings may encourage the deposition and organization of newly formed collagen fibers and granulation tissue in the wound bed. The composition that coats the matrix material may comprise a polymer. So, the matrix may be coated with the enzyme, the substrate and the polymer; or the enzyme, the substrate and the polymer may each be deposited on the matrix material. The polymer may assist in binding or adhering the enzyme and the substrate to the matrix material. For example, the polymer may form a film, coating or layer which binds the substrate, enzyme and matrix material.

Preferably, the polymer is soluble in an organic, or non-aqueous, solvent. The polymer may be water soluble. The polymer is preferably a synthetic polymer. The polymer may be biodegradable or bioerodable. In some embodiments, the polymer is selected from polyethylene oxide (or polyethylene glycol (PEG)), polyvinyl alcohol and polyvinylpyrrolidone. Other polymers may include poly(lactic-co-glycolic acid), polyglycolic acid, polylactic acid, polycaprolactone, polymeric surfactants, polyacrylic acid, polyacrylamide, N-(2-hydroxypropyl) methacrylamide (HPMA), polyoxazolines, polyphosphates or polyphosphazenes. Another suitable polymer may be phosphino-carboxylic acid (PCA). In a preferred example, the polymer is, or comprises PEG. The polymer which coats, or is deposited on, the matrix may thus be distinct from any polymer which forms part of the matrix material. For example, the matrix material may comprise carboxymethyl cellulose and the polymer which coats the matrix material, and assists in adhering the enzyme and substrate to the polymer material, may be PEG.

The enzyme may be provided on, or immobilised to, a polymer carrier, such as a PEG carrier.

According to the invention, there is provided an antimicrobial matrix comprising a matrix material coated with enzyme that is able to convert a substrate to release hydrogen peroxide; and substrate for the enzyme, wherein the matrix is substantially free of water; and wherein the matrix material is coated with polymer.

According to the invention, there is provided an antimicrobial matrix comprising a matrix material coated with enzyme that is able to convert a substrate to release hydrogen peroxide; and substrate for the enzyme, wherein the matrix is substantially free of water; and wherein the matrix material comprises a gel-forming material.

According to the invention, there is provided an antimicrobial matrix comprising a matrix material coated with enzyme that is able to convert a substrate to release hydrogen peroxide; and substrate for the enzyme, wherein the matrix is substantially free of water; and wherein the matrix material comprises collagen.

According to the invention, there is provided an antimicrobial matrix comprising a matrix material coated with enzyme that is able to convert a substrate to release hydrogen peroxide; and substrate for the enzyme, wherein the matrix is substantially free of water; and wherein: a) the matrix material is coated with polymer; and/or b) the matrix material comprises i) a gel forming material and/or ii) collagen.

The present invention is also directed to a method of making matrices of the invention. According to the invention, there is provided a method for making an antimicrobial matrix that has enzyme that is able to convert a substrate to release hydrogen peroxide and a substrate for the enzyme. The method may comprise contacting matrix material with substrate and enzyme, substantially in the absence of water. This may be achieved by contacting a solution comprising non-aqueous solvent, enzyme, substrate and optionally a polymer, with the matrix material. For example, the method may comprise applying the solution to the surface of the matrix material and allowing the solution to dry on the surface of the matrix material. Alternatively, it is achieved by contacting matrix material with the substrate, wherein the substrate is in a dry, solid phase; and contacting the matrix material with the enzyme, wherein the enzyme is in a solution comprising a non-aqueous solvent and optionally a polymer. This may be beneficial if it is difficult to dissolve the substrate in non-aqueous solvent.

Consequently, the invention may provide a method for making an antimicrobial matrix that has enzyme that is able to convert a substrate to release hydrogen peroxide and a substrate for the enzyme, the method comprising: contacting matrix material with the substrate, wherein the substrate is in a solid phase; and contacting the matrix material with the enzyme, wherein the enzyme is in a solution comprising a non-aqueous solvent, and optionally a polymer.

The substrate may be added to the matrix material in an anhydrous form. The substrate may be in the form of a powder or granules. The granules may be distributed substantially evenly over a surface of the matrix material. This may be achieved by sprinkling or atomisation.

The substrate granules may have a particular particle size distribution. For example, the particles of may have a mean diameter of 500 pm or less, 250 pm or less, 200 pm or less, 150 pm or less, 100 pm or less, 50 pm or less, 25 pm or less, or 10 pm or less. The particles may have a mean diameter of at least 2.5 pm, at least 5 pm, or at least 10 pm. The particles may have a mean particle diameter of 2.5 to 500 pm, 5 to 250 pm, or 10 to 100 pm. Less than 10% of the particles may have a diameter in excess of 200 pm. Less than 10% of the particles may have a diameter in excess of 100 pm. Less than 10% of the particles may have a diameter in excess of 50 pm. Less than 10% of the particles may have a diameter in excess of 25 pm. Less than 10% of the particles may have a diameter of less than 2.5 pm. Less than 10% of the particles may have a diameter of less than 5 pm. Less than 10% of the of the particles may have a diameter of less than 10 pm. Particle size of powders or granules is conventionally reported in terms of diameter irrespective of the actual particle shape; commonly the equivalent sphere diameter, such as defined by ISO 9276. Particle size analysis may be undertaken, for example, by image analysis using equivalent projected circle area or Feret diameters. Particle size distribution may be analysed using dynamic image analysis (DIA), sieve analysis or static laser light scattering (SIS).

The solution comprising the non-aqueous solvent, the enzyme and optionally the substrate and/or polymer is preferably applied to the matrix material by spraying. This may permit even coverage of the matrix material and may assist in rapid evaporation of the solvent.

The solution is preferably a non-aqueous solution, thus comprising substantially no water. However, the solution could conceivably comprise water, preferably low amounts of water. For example, the solution could have less than 10% by weight water, preferably less than 5% by weight water, more preferably less than 2% by weight water.

The non-aqueous solvent is preferably an organic solvent, e.g. a polar organic solvent. The non-aqueous solvent may be an alcohol such as isopropyl alcohol. It is preferable that the non- aqueous solvent is volatile so that it may readily evaporate during manufacture of the matrix.

For example, the non-aqueous solvent may have a vapour pressure of at least 3 kPa at 25 ² C, preferably at least 4 kPa at 25 ² C. The non-aqueous solvent, preferably has a boiling point less than 100 ² C, preferably less than 90 ² C.

In one example, the solution comprises at least 80% by weight non-aqueous solvent. In another example, the solution comprises at least 90% by weight non-aqueous solvent In another example, the solution comprises at least 95% by weight non-aqueous solvent. In another example, the solution comprises at least 99% by weight non-aqueous solvent.

The solution may comprise 0.005 to 1% by weight enzyme. For example, the solution may comprise 0.05 to 0.5% by weight enzyme.

The method of the invention may comprise the step of forming the solution. For example, this may include dissolving the enzyme, and optionally the substrate and/or polymer, in the solvent.

The method may comprise contacting the matrix material with the enzyme prior to contacting the matrix material with the substrate; or contacting the enzyme and the substrate with the matrix material concurrently, or simultaneously. Preferably, the method comprises contacting the matrix material with the substrate prior to contacting the matrix material with the enzyme. This may assist in the adhesion or binding of the glucose to the matrix, particularly if the substrate is in a dry, solid form. References herein to “enzyme” encompass one or more enzymes. For example, in some embodiments, matrices of the invention may comprise a plurality of enzymes that are able to convert a substrate to release hydrogen peroxide. In some embodiments, matrices of the invention may comprise only one enzyme that is able to convert a substrate to release hydrogen peroxide.

Preferably, the enzyme is a purified enzyme. The term “purified enzyme” is used herein to include an enzyme preparation in which the enzyme has been separated from at least some of the impurities originally present when the enzyme was produced. Preferably impurities that have been removed or reduced include those that would otherwise interfere with the ability of the enzyme to convert the substrate to release hydrogen peroxide. Examples of suitable purity levels (mass purity) include at least 90% pure, at least 95% pure, or at least 98% pure. Most preferably, the enzyme is at least 99% pure.

The enzyme may have been produced by recombinant or non-recombinant means, and may be a recombinant or non-recombinant enzyme. The enzyme may be purified from a microbial source, preferably from a non-genetically modified microbe.

Preferably, the enzyme is, or comprises, an oxidoreductase enzyme. Examples of oxidoreductase enzymes include glucose oxidase, hexose oxidase, cholesterol oxidase, galactose oxidase, pyranose oxidase, choline oxidase, pyruvate oxidase, glycollate oxidase, amino acid oxidase, or mannose oxidase.

Preferably, the oxidoreductase enzyme is glucose oxidase and the substrate for the oxidoreductase enzyme is glucose.

References herein to “substrate” encompass one or more substrates. For example, in some embodiments, matrices of the invention may comprise a plurality of substrates. In some embodiments, matrices of the invention may comprise only one substrate.

Preferably, the substrate is a purified substrate. The term “purified substrate” is used herein to include a substrate which has been separated from at least some of the impurities originally present when the substrate was obtained or produced. The purified substrate may be obtained from a natural source or may be synthetically produced. The purified substrate may be a processed, extracted, or refined substrate (i.e. a substrate in which impurities or unwanted elements have been removed by processing). The substrate may be 90%, 95%, or 99% pure (mass purity). However, in some embodiments, it may be desirable that the purified substrate is a medical grade, medical device grade, or pharmaceutical grade substrate. In particular embodiments, the substrate is, or comprises, sugar. The term “sugar” is used herein to refer to a carbohydrate with the general formula C _m (H ₂ 0) _n . The purified sugar may be obtained from a natural source (for example a processed, extracted, or refined natural sugar), or be synthetically produced. The sugar may be at least 10%, 20%, 30%, 40%, 50%, 60%,

70%, 80%, 90%, 95%, or 99% pure (mass purity). Preferably the purity level is at least 90%. Even more preferably, the purity is at least 99%. The sugar may be a medical grade, medical device grade, or pharmaceutical grade sugar. The sugar may be a monosaccharide or a disaccharide, preferably a monosaccharide. The sugar may include, for example purified D- glucose, hexose, or D-galactose. For example, the purified sugar may be medical grade, medical device grade, or pharmaceutical grade D-glucose, hexose, or D-galactose. The sugar may be an anhydrous sugar. For example, the glucose may be anhydrous glucose.

Matrices of the invention, or components of matrices of the invention, may be pharmaceutical grade. The term “pharmaceutical grade” is used herein to refer to include reference to a purity standard for a reagent that has been established by a recognized national or regional pharmacopeia (e.g., the U.S. Pharmacopeia (USP), British Pharmacopeia (BP), National Formulary (NF), European Pharmacopoeia (EP), or Japanese Pharmacopeia (JP)).

Instead of, or in addition to, the substrate, the matrix may comprise a precursor substrate. Any disclosure herein which relates to the substrate, such as amounts and purity, may also apply to the precursor substrate.

For matrices of the invention which comprise a precursor-substrate, the matrix may comprise one or more enzymes for converting the precursor-substrate to the substrate for the enzyme. However, in some embodiments, the precursor-substrate may not necessarily be converted to the substrate enzymatically. For example, for some precursor substrates, addition of water may be sufficient for conversion. Alternatively or additionally, matrices of the invention may comprise non-enzymatic catalysts.

Matrices which comprise a precursor-substrate may comprise a first enzyme that is able to convert the substrate to release hydrogen peroxide, and a second enzyme that is able to convert the precursor-substrate to the substrate for the first enzyme.

The precursor-substrate is preferably a carbohydrate, such as a polysaccharide, or a sugar e.g. a disaccharide, or sugar derivative. For example, the precursor-substrate may be sucrose, the first enzyme may be glucose oxidase and the second enzyme may be invertase. In another example, the precursor-substrate may be maltose, the first enzyme may be glucose oxidase and the second enzyme may be maltase. Matrices of the invention which comprise a precursor-substrate may comprise an enzyme (preferably a purified enzyme) that is able to convert the substrate to release hydrogen peroxide, and at least two enzymes (e.g. second and third enzymes, preferably purified enzymes) that are able to convert the precursor-substrate to the substrate for the first enzyme. For example, the precursor-substrate may be starch, the first enzyme may be glucose oxidase and the second and third enzymes may be amylase and maltase. For example, the precursor- substrate may be cellulose, the first enzyme may be glucose oxidase and the second and third enzymes may be cellulose and beta-glucosidase.

Matrices of the invention are preferably substantially free of non-aqueous solvent. Although matrices of the invention may employ non-aqueous solvent in their manufacture, as described herein, it is preferable that the non-aqueous solvent evaporates during manufacture to produce a substantially dry matrix. Of course, trace amounts of the non-aqueous solvent may remain.

Matrices of the invention may comprise antioxidant. Antioxidant may consist of one antioxidant or may consist of a plurality of antioxidants. Suitable antioxidants include ascorbic acid, tocopherol or ascorbyl palmitate. Ascorbic acid may be preferred. Antioxidant may be present in an amount of at least 0.01% by weight or at least 0.1% by weight. Antioxidant may be present in an amount of 2% by weight, or less, 1% by weight, or less, or 0.5% by weight, or less. For example, in some embodiments, antioxidant is present in an amount of 0.1 to 0.5% by weight, such as 0.25% by weight.

Matrices of the invention may be wound dressings or they may be tissue matrices for use in tissue regeneration.

In methods of the invention, antioxidant may be in the solution which is applied to the matrix material.

Matrices of the invention preferably contain substantially no catalase. Matrices of the invention preferably contain essentially no catalase.

Matrices of the invention preferably contain substantially no peroxidase. Matrices of the invention preferably contain essentially no peroxidase.

Matrices of the invention preferably contain substantially no lactoferrin. Matrices of the invention preferably contain essentially no lactoferrin.

Matrices of the invention preferably contain substantially no zinc oxide. Matrices of the invention preferably contain essentially no zinc oxide. Matrices of the invention preferably do not comprise an unrefined substance. The term “unrefined” is used herein to refer to substances that have not been processed into a pure form. Unrefined substances include substances that may have been concentrated, for example by drying or boiling.

Matrices of the invention preferably do not include one or more substrates from a natural source (termed herein a “natural substance”). Examples of natural substances include substances from a plant source, including from sap, roots, nectar, flowers, seeds, fruit, leaves, or shoots.

Preferably, matrices of the invention do not comprise an unrefined natural substance. Matrices of the invention preferably do not comprise honey.

In some matrices of the invention, there is substantially no oil or other lipophilic phase. Matrices of the invention preferably do not comprise an emulsion.

Matrices of the invention are preferably sterile. Matrices of the invention may be sterilised by any suitable means. Preferably matrices of the invention have been sterilised by irradiation. Irradiation may be achieved by gamma, electron beam or X-ray. The Applicant has found that matrices can retain glucose oxidase activity (and, therefore, the ability to release hydrogen peroxide on dilution) following sterilisation by exposure to gamma irradiation or electron beam irradiation. A suitable level of gamma irradiation is 10-70 kGy, preferably 25-70 kGy, more preferably 35-70 kGy. Alternatively, matrices of the invention may be sterilised by electron beam irradiation. A suitable level or dose of irradiation (e.g. electron beam irradiation) may be 10-100 kGy, preferably 30-80 kGy, more preferably 50-80kGy. The dose may be greater than 35 kGy. The dose may be less than 80 kGy, for example 75 kGy or less.

There is also provided according to the invention a method of sterilising a matrix of the invention. Preferably, the method comprises exposing the matrix to irradiation, preferably gamma irradiation or electron beam irradiation.

Since ozone has not been authorised by the US FDA for sterilisation of honey-based products for use in wound healing, matrices according to the invention preferably have not been sterilized by ozonation, and do not include ozone, or any components that have been subjected to sterilisation by ozonation.

Matrices of the invention may be in a container or sachet. The container may assist in maintaining the sterility of the matrix. Preferably, the container or sachet is sealed or airtight. Matrices of the invention can be used to treat, ameliorate or prevent any microbial infection that can be treated by hydrogen peroxide. Examples include infection caused by gram positive bacteria, gram negative bacteria, acid-fast bacteria, viruses, yeasts, parasitic or pathogenic micro-organisms or fungi. For example, infections caused by the following micro-organisms may be treated: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Propionibacterium acnes, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophytics, Beta haemolytic Streptococci Group A or B, Campylobacter coli, Campylobacter jejuni, Methicillin Resistant Staphylococcus Aureus (MRSA), Methicillin Sensitive Staphylococcus Aureus (MSSA), Botrytis cinerea, Mycobacterium tuberculosis, Cryptosporidium, Plasmodium, Streptococcus pyogenes, Streptococcus zooepidemicus and Toxoplasma.

The invention also provides a method of preventing or treating a microbial infection, for example a microbial infection that comprises a biofilm, or a microbe that is capable of forming a biofilm, wherein the method comprises administering a matrix of the invention to a site of the infection.

Matrices of the invention may be used to treat animals. Matrices of the invention may be used to treat humans. Matrices of the invention may be topically administered.

There may be provided matrices of the invention for use in the treatment of a microbial infection that comprises a biofilm.

A matrix of the invention may be used in a method of wound care, including the treatment of a wound, or the treatment or management of wound sepsis. The wound may be an acute wound, chronic wound, surgical wound (for example, a Caesarean wound), chronic burn, or an acute burn. A matrix of the invention may be used in the prophylactic prevention of wound sepsis.

Matrices of the invention may be used to treat chronic wounds or wounds that are critically colonized. The term “critically colonized” is often used to refer to a wound that has reached a critical point at which bacteria begin to negatively affect the wound and begin to elicit signs of their presence. A critically colonized wound may indicate the presence of a biofilm. A bacterial load of greater than 10 ⁵ organisms/gram of tissue is often accepted as impeding wound healing (Siddiqui AR, Bernstein JM (2010) Chronic wound infection: Facts and controversies. Clinics in Dermatology 28: 519-26; Edmonds, M., & Foster, A. (2004). The use of antibiotics in the diabetic foot. Am J Surg, 187(5A), 25S-28S. Consequently, matrices of the invention may be used to treat wounds that have a bacterial load of greater than 10 ⁵ organisms/gram of tissue.

Matrices of the invention may be administered to a patient, such as placed on the wound of a patient, for a period of at least 24 hours or 48 hours or, more preferably, 72 hours. There is also provided according to the invention a method of treating inflammation, which comprises administering a matrix of the invention to a site of inflammation.

There is also provided according to the invention a method of stimulating tissue growth, which comprises administering a matrix of the invention to a site in need of such stimulation.

There is also provided according to the invention a method of debriding a wound, which comprises administering a matrix of the invention to a wound in need of debridement.

There is also provided according to the invention a method of deodorising a wound, which comprises administering a matrix of the invention to a wound in need of deodorising.

A matrix of the invention may be provided with instructions for use of the composition. For example, a matrix of the invention may be packaged as a kit with the instructions.

Embodiments of the invention are now described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 shows a dressing of the invention produced in accordance with a method of the invention;

Figure 2 shows the dressing of Figure 1 following exposure to water and contact with a Quantofix® peroxide test strip.

Example 1 - Formation of a wound dressing

1 . Sieve Glucose powder (Fisher Scientific™; product code G/0500/65) 100# and apply a fine ‘dusting’ to a modified cellulose wound dressing material (supplied by SFM Limited, Coventry, UK).

2. Dissolve glucose oxidase (BBI solutions; product code: G03B2) provided on a polyethylene glycol carrier into Isopropyl alcohol (0.25% by weight) and apply a fine mist to would dressing by spray application.

3. Allow to air dry (30 ² C for 2 hours).

The resulting wound dressing is shown in Figure 1 . Example 2 - Results & Testing

5 drops of water applied (approx. 200mg) were applied to the dressing. 5 seconds later a Quantofix® peroxide test strip was used to assess the presence of hydrogen peroxide the results are shown in Figure 2. Hydrogen peroxide activity was instant and significant.