Polyurethane foam composition for treatment of burns and wounds of various etiologies

Abstract

FIELD: medicine.SUBSTANCE: group of inventions relates to a polyurethane composition intended for the treatment of burns and healing of wounds of various etiologies, containing: component A, which is a mixture of components in the following ratio in the composition, wt.%: high-molecular trifunctional polyester based on propylene and ethylene oxides with a molecular weight of 5000–6000 units – 100; foaming agent: distilled water – 3.0–5.5; foam opener: high-molecular trifunctional polyester – 0.25–2.5; emulsifier, foam stabilizer: triethanolamine (TEA) – 0.8–1.4; foam hardener: triethylenediamine (TEDA) – 0.1–1.2; chain extender: diethanolamine (DEA) – 0.2–1.5; foaming catalyst: dimethylethanolamine (DMEA) – 0.15–2.4; urethane formation activator: tegoamine BDE – 0.1–0.4; and component B, which is an isocyanate component, namely aromatic diphenylmethane diisocyanate – 30–50 wt.%, and also to the use of the said composition for obtaining a polyurethane foam coating in the form of a dressing for the treatment of burns and wounds of various etiologies.EFFECT: increase in the reliability of the use of the claimed polyurethane foam composition, compared to the prototype, in its antibacterial properties, and increase in the absorption capacity and sorption capacity of the resulting foam, which in turn leads to an increase in the sorption capacity and, as a consequence, to effective treatment, allowing for a reduction in wound healing time.2 cl, 9 dwg, 3 tbl, 11 ex

Description

[0001] The invention relates to the field of medicine, in particular to traumatology, surgery, and can be used for the treatment of burns, for the treatment of infected wounds, pain relief, and inflammation of the skin.

[0002] More specifically, the invention relates to a polyurethane foam (PUF) composition used in medical devices for the treatment of burns or wounds of various etiologies. The invention also relates to the use of the polyurethane foam composition for producing a foam coating in the form of a medical dressing, to a medical device, to a method for applying the resulting polyurethane foam coating, and to a method for treatment using the polyurethane foam coating.

[0003] The effectiveness of treating wounds of various etiologies, burn wounds is primarily due to the creation of a new polyurethane composition with improved properties.

[0004] STATE OF THE ART

[0005] From patent RU 2379060 (prototype), a gel-like dressing made of elastic polyurethane foam is known, consisting of a polyol component including a high-molecular simple oligoether polyol based on propylene oxide and ethylene oxide, water, a urethane formation activator, an isocyanate component including a mixture of diphenylmethane diisocyanate isomers, an activating additive consisting of a polyurethane chain extender, a foam opener, a foam hardener, wherein a foaming agent is additionally introduced into the activating additive, a mixture of tertiary amines and organotin compounds in a ratio of 1:1 (parts by weight) is used as an activator, an isocyanate component with an isocyanate group content of 26.0-32% by weight with the following ratio of ingredients in the composition, parts by weight:

[0006] high molecular weight oligoether polyol 100 water 2,0-4,0 foaming agent 2,0-4,0 urethane formation activator (a mixture of tertiary amines and organotin compounds at a ratio of 1:1 (mass parts) 0,05-0,4 chain extender 0,2-1,5 foam opener 0,2-1,5 foam hardener 0,2-1,5 isocyanate component containing isocyanate groups 26.0-32.0 wt.% 30-60

[0007] Practical use of the proposed gel dressing revealed a number of disadvantages, which are as follows:

[0008] - the use of isopentane (boiling point 35.5°C) and n-pentane (boiling point 30°C) as low-boiling organic liquids in foaming agents. These liquids are flammable, which limits the use of this composition. It was found that during foaming, pentane vapors are released, forming a vapor-air mixture capable of igniting, for example, from a static spark. The use of such a composition is impossible, for example, in hot weather, in the field, and other conditions of elevated temperatures. Another negative factor is that swelling may occur during storage of the composition;

[0009] - Use of a tertiary amine system with an organotin compound as a catalyst. It should be noted that the organotin compound belongs to hazard class I, is toxic, and can cause a number of irreversible side effects when used on wounds. According to the examples in the patent description, dibutyltin dioleate is used as the organotin compound. Dibutyltin dioleate is included in the list of hazardous toxic substances according to the Federal State Budgetary Institution "Russian Register of Potentially Hazardous Chemical and Biological Substances" (Rospotrebnadzor, No. 07 / 22-1727, dated November 30, 2012), number in the Federal Register of Potentially Hazardous Chemical and Biological Substances: series BT No. 003423.

[0010] During long-term treatment, the use of such a toxic substance in a well-known gel dressing can cause complications during treatment, such as dermatitis and eczema. Therefore, using a toxic substance in a wound dressing is extremely dangerous.

[0011] From patent RU 139960, disclosing a utility model, a polyurethane foam coating is known for treating burns, wounds or other skin damage, formed from a mixture of initial components directly on the damaged skin surface to obtain a three-dimensional foam-like structure with a hardened outer layer and an elastic inner layer, wherein as a mixture of initial components a mixture based on polyol and isocyanate components in a ratio of (3.0-3.5):1 is used, where as a polyol component a composition of the following composition is used, mass parts:

[0012] foam regulator containing high molecular weight polyol 100 water 2,0-4,0 foaming agent 2,0-4,0 urethane formation activator 0,05-0,4 chain extender 0,2-1,5 foam opener 0,2-1,5 foam hardener 0,2-1,5

[0013] This document also discloses a single-use device for applying a medical polyurethane foam coating. The known device is designed as a flexible container comprising at least two sealed sections, one of which contains a polyol component and the other an isocyanate component in a ratio of (3.0-3.5):1, wherein said sections are separated by a partition configured to remove at least a portion of said partition, as well as a means for discharging a mixture of the initial components of the foam structure to obtain a coating.

[0014] This patent document presents a general description of the composition of a polyurethane foam composition containing two main components: a polyol component and an isocyanate component. The ratio of the two main components, the polyol component to the isocyanate component, is disclosed as being 3.0-3.5:1.

[0015] Thus, the urgent task is to search for new effective means for the treatment of wounds of various etiologies, expanding the arsenal of known means for this purpose, accessible and without toxic side effects.

[0016] The objective of the proposed invention was to develop a new polyurethane foam (PUF) composition for producing a polyurethane foam coating (dressing) with improved properties for treating various wounds, particularly burns, in hospital settings, harsh extreme conditions, and field conditions. This composition would eliminate all of the aforementioned disadvantages. There was also a continuing need for a PUF composition that would eliminate toxic components while maintaining the foam's effective properties. The development of this new PUF composition and a medical device containing it expanded the arsenal of available treatments for burns and wounds of various etiologies.

[0017] Thus, the problem that the present invention is aimed at solving was to create a highly effective means for treating wounds of various etiologies, made in the form of a polyurethane foam coating that has antimicrobial properties and promotes a positive course of the wound process.

[0018] The present inventors unexpectedly discovered an increase in the effectiveness of the claimed polyurethane foam composition. Testing revealed antibacterial properties of the resulting polyurethane foam composition, as well as increased absorption and sorption capacity of the resulting foam. This, in turn, led to increased sorption capacity and, consequently, to effective treatment, reducing wound healing time.

[0019] SUMMARY OF THE INVENTION

[0020] The present invention relates to a polyurethane foam composition created on the basis of two components A and B. Component A is in the form of a mixture, and along with other ingredients, includes a high-molecular trifunctional polyester based on propylene and ethylene oxides with a molecular weight of 5000-6000 units. Component B is an isocyanate component, namely aromatic diphenylmethane diisocyanate.

[0021] An important aspect of the present invention is the qualitative and quantitative composition of the components used, in particular the content in component A of a foaming agent, a foam opener, an emulsifier, a foam hardener, a chain extender, a foaming catalyst, and a urethane formation activator.

[0022] More specifically, the objective of the present invention was to create a new polyurethane foam composition for the treatment of wounds of various etiologies, including burns, containing component A, which is a mixture of components in the following ratio in the composition, mass parts:

[0023] - high molecular weight trifunctional polyester based on propylene and ethylene oxides with a molecular weight of 5000-6000 units. 100 - foaming agent: water, distilled 3,0-5,5 - foam opener (high molecular weight) trifunctional polyester) 0,25-2,5 - emulsifier, foam stabilizer: triethanolamine (TEA) 0,8-1,4 - foam hardener: triethylenediamine (TEDA) 0,1-1,2 - chain extender: diethanolamine (DEA) 0,2-1,5 - foaming catalyst: dimethylethanolamine (DMEA) 0,15-2,4 - urethane formation activator: tegoamine BDE 0,1-0,4

[0024] and component B, which is an isocyanate component, namely aromatic diphenylmethane diisocyanate - 30-50 mass parts,

[0025] possesses antibacterial properties, high absorption capacity and increased sorption capacity without limiting use in relation to various types of wounds and burns, age and specific groups of patients, due to the synergistic effect of effective amounts of the components of the composition.

[0026] According to the main aspect of the claimed invention, component B is a polymeric aromatic diphenylmethane diisocyanate with an isocyanate group content of 29.7. This polyisocyanate is a reactivity-modified prepolymer based on diphenylmethane diisocyanate (MDI) containing several highly functional isocyanates. The structure of this type of polyisocyanate reduces the exothermic effect of the polyurethane foam formation reaction on the victim's wound.

[0027] Unexpectedly, the inventors discovered that the stated quantitative composition of the components in the claimed polyurethane foam composition enables the resulting polyurethane foam composition to achieve antibacterial properties, increase absorption capacity, and enhance sorption capacity. Experiments revealed that varying the quantitative composition of the components in the claimed polyurethane foam composition does not achieve the required synergistic effect that would lead to effective treatment and reduce wound healing time.

[0028] One important aspect of the present invention is that the claimed composition does not contain hazardous or toxic substances, in particular foaming agents in the form of low-boiling liquids (isopentane, N-pentane) or organotin compounds. According to the present invention, water is used as a foaming agent in an amount of 3.0-5.5 parts by weight, which in turn eliminates the formation of a vapor-air mixture, thereby eliminating the fire hazard of the composition and does not require additional safety measures when applying the dressing to the wound, which is necessary, for example, when using pentane or its isomers as a foaming agent to produce a dressing with a similar effect.

[0029] According to the stated composition of the polyurethane foam composition, water not only acts as the initial participant in the elongation of the prepolymer's macromolecular chain (the reaction between isocyanate and a high-molecular compound) to form urea (an intermediate step in polyurethane production), but also as an active foaming agent as its concentration increases, resulting in the formation of greater amounts of carbon dioxide. Its combination with tertiary amines allows for smooth foaming control and a lower structuring temperature for the polyurethane foam coating applied to the wound, reducing pain in patients.

[0030] The authors of the present invention also discovered that carbon dioxide, formed during the reaction of isocyanate with water in large quantities (after the chemical reaction, the composition increases in volume 25-35 times), has antiseptic properties, killing many types of bacteria, viruses, and fungi. Moreover, unlike many antiseptics, carbon dioxide does not have a destructive effect on tissue, as the body's cells have an antioxidant defense system.

[0031] According to the main aspect of the present invention, dimethylethanolamine (DMEA) is used as a foaming catalyst. It is bifunctional, containing both a tertiary amine and a primary alcohol as functional groups. The foaming catalyst activates the gas evolution reaction and regulates the amount of carbon dioxide released, which in turn influences the formation of more pores.

[0032] Table 1 below illustrates the comparative characteristics of the claimed composition and the composition according to patent RU 2379060.

[0033] According to Table 1, according to the present invention, an increase in the number of open pores by 36%, vapor permeability by 115%, sorption capacity by 86%, absorption capacity after 2 hours by 26% and absorption capacity per day by 35% were found.

[0034] Table 1

[0035] Polyurethane foam composition according to the invention RU 2379060 Vapor permeability, mg / cm2*hour 6,23 2.9 Absorption capacity for 2 hours, g / g 6,18 4,89 Absorption capacity for 1 day, g / g 7,56 5,57 Sorption capacity, % 778 418 Porosity, % (open pores) 78 57

[0036] It was found that the introduction of triethanolamine (TEA) into the composition as an emulsifier and stabilizer for the resulting foam facilitates the process of mixing all components together and regulates open porosity by reducing the surface tension coefficient between the gas phase (CO2) and the liquid phase of the composition, and as a consequence, increases the number of open pores.

[0037] The introduction of tegoamine BDE into the composition as an activator of urethane formation allows for a significant increase in the rate of foaming without increasing the temperature of the polyurethane foam coating formation process and, as a result, a reduction in the time of its formation, with the formation of a soft and highly flexible surface layer.

[0038] Thus, the task was solved through the qualitative and quantitative composition of all components in the proposed composition, which made it possible to achieve an unexpected synergistic effect.

[0039] Also, an unexpected effect is due to the production of a highly elastic polyurethane foam wound dressing with a 3-fold reduction in the formation time of stable foam compared to the prototype, a decrease in the dressing formation temperature and an increase in antibacterial properties in accordance with Tables 2 and 3 below.

[0040] Table 2

[0041] Technological sample data Polyurethane foam composition according to the invention RU 2379060 Start time, s 21 22 Gel time, s 53 120 Tack-free time (formation of stable foam), min. 5 12 Dressing temperature, °C 39 42

[0042] The above tests revealed that determining the optimal reaction temperature (about 39°C) while reducing the gelation time and structuring of the dressing due to the optimal effective qualitative and quantitative content of the components in the claimed composition leads to a reduction in additional pain in patients.

[0043] Table 3

[0044] Strains of microorganisms The growth rate of a crop under a polyurethane foam coating of the composition according to the invention Staphylococcus aureus ++ Pseudomonas aeruginosa ++

[0045] The presence and growth rate of microbial cultures on the surface of the nutrient medium are determined using the 4-cross system:

[0046] + - weak, insignificant growth,

[0047] ++ - suppressed growth,

[0048] +++ - moderate growth,

[0049] ++++ - intensive growth.

[0050] As shown in Table 3, the polyurethane foam composition according to the invention exhibits antibacterial properties against all tested cultures. This is an important aspect in the effective treatment of burns and other skin lesions, where the treatment process reveals an increase in microbial infection and the possibility of a secondary infection occurring.

[0051] Thus, the technical result according to the present invention is achieved due to the synergistic action of the components of the claimed polyurethane foam composition, followed by obtaining a viscoelastic bandage with a highly effective therapeutic effect.

[0052] During the tests, the authors of the present invention found that the obtained polyurethane foam composition has an unexpected synergistic effect aimed at improving the sorption capacity of the resulting foam, obtaining an antibacterial effect of the composition, and reducing the wound healing time.

[0053] Another aspect of the present invention is the use of a composition for producing a polyurethane foam coating in the form of a dressing for treating wounds of various etiologies, including wounds formed as a result of burns.

[0054] Also another aspect of the present invention is a medical product containing the claimed polyurethane foam composition, which is an individual package, the features of which allow the properties of the components of the composition to be preserved, which is a “sachet package” divided by a perforation line into two zones, one of which contains the polyol component A, and the other contains the isocyanate component B, made with the possibility of rupturing this perforation by increasing the pressure in the chambers by compressing and mixing the two zones to obtain a polyurethane foam coating.

[0055] One of the embodiments of the given medical product containing components A and B may be the medical product shown in Fig. 1, containing a polyurethane composition according to the present invention, which is an individual package - a sachet package in the form of a "bottle", divided by a perforation line into two zones, in one of which is A, and in the other component B, made with the possibility of breaking this perforation and mixing the two zones to obtain a polyurethane foam coating, with the possibility of easy squeezing and uniform distribution of the coating on the surface of any wound.

[0056] Also, obtaining the declared polyurethane foam composition is not limited to the use of sachet packages; it is possible to use two-component syringes with a mixer, an automatic stationary dispenser for closing wounds of different sizes, and a pressure container.

[0057] Another aspect of the present invention is a method for applying a polyurethane composition, according to which, in order to rupture a sachet package, it is necessary to first twist the package in the direction of the arrow, then press on the sides of the package until the central seam is torn, unfold the package to its original state, intensively rubbing the chambers of the package together, mix the contents until they increase in volume, immediately tear off the upper corner along the notch and apply the coating to the wound, capturing areas of dry skin around the wound.

[0058] Alternative methods of applying the composition include using two-component syringes with a mixer instead of a sachet, the operating principle of which is identical, but allows you to use a syringe to regulate the amount of composition poured onto the wound.

[0059] Also an important aspect of the present invention is a method for treating burns, wounds, pain of various etiologies, inflammation of the skin using the claimed medical product, leading to a reduction in wound healing time.

[0060] Thus, the technical result is that the present polyurethane foam composition has an unexpected synergistic effect aimed at enhancing antibacterial properties, increasing the sorption capacity and healing time of wounds of various natures, in inpatient, hospital, military, field and extreme conditions, and at various ambient temperatures.

[0061] Thus, the components in the claimed composition are present in effective amounts. However, research unexpectedly revealed that less than the stated amount of components was ineffective, and more than the stated amount was inappropriate, as it did not enhance the positive effect.

[0062] EMBODIMENT OF THE PRESENT INVENTION

[0063] Below are examples confirming the implementation of obtaining the declared polyurethane foam composition, its application to wounds under different conditions, its antibacterial properties, and sorption properties.

[0064] Example #1

[0065] Obtaining the claimed polyurethane foam composition and coating in the form of a bandage, which is a spongy material

[0066] The method for obtaining the claimed composition and coating consists of the following steps:

[0067] 1. Preliminary production of component A in accordance with the declared composition.

[0068] Component A is prepared from a mixture of all necessary ingredients, namely high-molecular-weight polyesters, water, emulsifier, foam stabilizer, foam hardener, catalyst, and urethane activator. Component A is produced in a production facility using specialized equipment.

[0069] The following components are added and mixed into a high-molecular trifunctional polyester based on propylene and ethylene oxides with a molecular weight of 5000-6000 units in accordance with the composition: emulsifier, foam stabilizer, foam hardener, catalyst and urethane formation activator.

[0070] 2. Packing components A and B into closed containers (e.g., a sachet or other closed container with two separated cavities) using dry nitrogen.

[0071] 3. Mixing components A and B.

[0072] Components A and B are mixed immediately before use in a closed container (for example, a sachet or other closed container with two separated cavities) in a ratio of A:B = 2.0-3.3:1, until the moment the mixed composition increases in volume and heats up slightly.

[0073] 4. Applying the mixed composition to the target surface.

[0074] The mixed composition is applied to the target surface.

[0075] Open the sachet by removing the corner of the sachet, pour the contents onto the wound surface and smooth out the edges if necessary using a spatula or other tool.

[0076] 5. Formation of polyurethane foam bandage on the affected surface.

[0077] Within 3-5 minutes, depending on the ambient temperature and the temperature of the components, the polyurethane foam hardens (forms) on the wound (or on the target surface) in the form of a porous sponge, ensuring wound closure.

[0078] Example #2

[0079] The polyol component (A) is prepared by thoroughly mixing 100 parts by weight of high-molecular trifunctional polyester based on propylene and ethylene oxides with a molecular weight of 5000-6000 units, as well as 3 parts by weight of a blowing agent (water), 0.25 parts by weight of a foam opener (high-molecular trifunctional polyester, in particular Sintepol 1422), 0.8 parts by weight of an emulsifier, foam stabilizer (TEA), 0.1 parts by weight of a foam hardener (TEDA), 0.2 parts by weight of a chain extender (DEA), 0.15 parts by weight of a foaming catalyst (DMEA), 0.1 parts by weight of a urethane formation activator (tegoamine BDE).

[0080] Diphenylmethane diisocyanate Suprasec 2456 was used as the isocyanate component (B) - 30 parts by weight per 100 parts by weight of polyol component A.

[0081] The composition is prepared by mixing component A and component B in a 20 ml sachet, followed by manual mixing. Mixing is continued for 35 seconds. The sachet is then opened, and the resulting composition is applied to the wound surface. After 200 seconds of mixing, the composition transforms into a porous sponge that adheres firmly to the wound surface. Over the next 100 seconds, the PU sponge exhibits relatively low tackiness, which decreases over time and virtually disappears after 420 seconds of application.

[0082] The composition foams quickly on the wound.

[0083] Foaming parameters:

[0084] Start - 35 sec,

[0085] Gel - 115 sec

[0086] Rise - 150 sec,

[0087] Tack-free - 425 sec,

[0088] The temperature at the coating surface is 39°C.

[0089] Example #3

[0090] Polyol component (A) is prepared by thoroughly mixing 100 parts by weight of high-molecular trifunctional polyester based on propylene and ethylene oxides with a molecular weight of 5000-6000 units, as well as 5.5 parts by weight of blowing agent (water), 2.5 parts by weight of foam opener (high-molecular trifunctional polyester, 1.4 parts by weight of emulsifier, foam stabilizer (TEA), 1.2 parts by weight of foam hardener (TEDA), 1.5 parts by weight of chain extender (DEA), 2.4 parts by weight of foaming catalyst (DMEA), 0.4 parts by weight of urethane formation activator (tegoamine BDE).

[0091] When producing a polyurethane composition, 50 parts by weight of isocyanate component (B) are added to 100 parts by weight of polyol component A.

[0092] The composition is prepared by mixing component A and component B in a 20 ml sachet, followed by manual mixing. Mixing is continued for 35 seconds. The sachet is then opened, and the resulting composition is applied to the wound surface. After 130 seconds of mixing, the composition transforms into a porous sponge that adheres firmly to the wound surface. For the next 30 seconds, the PU sponge exhibits relatively low tackiness, which decreases over time and virtually disappears within 180 seconds of application.

[0093] The composition foams quickly on the wound.

[0094] Foaming parameters:

[0095] Start - 18 sec,

[0096] Gel - 43 sec

[0097] Rise - 130 sec,

[0098] Tack-free - 180 sec,

[0099] The temperature at the coating surface is 39°C.

[0100] Example #4

[0101] The polyol component (A) is prepared by thoroughly mixing 100 parts by weight of high-molecular trifunctional polyester based on propylene and ethylene oxides with a molecular weight of 5000-6000 units, as well as 4.5 parts by weight of blowing agent (water), 1.97 parts by weight of foam opener (high-molecular trifunctional polyester, 1.25 parts by weight of emulsifier, foam stabilizer (TEA), 0.85 parts by weight of foam hardener (TEDA), 1.0 parts by weight of chain extender (DEA), 1.9 parts by weight of foaming catalyst (DMEA), 0.28 parts by weight of urethane formation activator (tegoamine BDE).

[0102] When producing a polyurethane composition, 32 parts by weight of isocyanate component (B) are added to 100 parts by weight of polyol component A.

[0103] The composition is prepared by mixing component A and component B in a 20 ml sachet, followed by manual mixing. Mixing is continued for 30 seconds. The sachet is then opened, and the resulting composition is applied to the wound surface. After 170 seconds of mixing, the composition transforms into a porous sponge that adheres firmly to the wound surface. For the next 40 seconds, the PU sponge exhibits relatively low stickiness, which decreases over time and virtually disappears after 240 seconds of application.

[0104] The composition foams quickly on the wound.

[0105] Foaming parameters:

[0106] Start - 22 sec,

[0107] Gel - 58 sec

[0108] Rise - 160 sec,

[0109] Tack-free - 240 sec,

[0110] The temperature at the coating surface is 39°C.

[0111] Example #5

[0112] The polyol component (A) is prepared by thoroughly mixing 80 parts by weight of high-molecular trifunctional polyester based on propylene and ethylene oxides with a molecular weight of 5000-6000 units, as well as 2 parts by weight of a blowing agent (water), 0.1 parts by weight. foam opener (high molecular weight trifunctional polyether, 0.3 parts by weight of emulsifier, foam stabilizer (TEA), 0.02 parts by weight of foam hardener (TEDA), 0.1 parts by weight of chain extender (DEA), 0.8 parts by weight of foaming catalyst (DMEA), 0.05 parts by weight of urethane formation activator (tegoamine BDE). Diphenylmethane diisocyanate Suprasec 2456 was used as the isocyanate component (B) - 20 parts by weight per 100 parts by weight of polyol component A.

[0113] The composition is prepared by mixing component A and component B in a 20 ml sachet, followed by manual mixing. Mixing is continued for 35 seconds. The sachet is then opened, and the resulting composition is applied to the wound surface. No foam was formed; the composition spread with a slight increase in volume, and large cavities and pits were observed. The stickiness persisted for the next 70 minutes.

[0114] Example #6

[0115] Polyol component (A) is prepared by thoroughly mixing 120 parts by weight of high-molecular trifunctional polyester based on propylene and ethylene oxides with a molecular weight of 5000-6000 units, as well as 6.5 parts by weight of blowing agent (water), 3.5 parts by weight of foam opener (high-molecular trifunctional polyester, 1.8 parts by weight of emulsifier, foam stabilizer (TEA), 2 parts by weight of foam hardener (TEDA), 1.8 parts by weight of chain extender (DEA), 2.8 parts by weight of foaming catalyst (DMEA), 0.5 parts by weight of urethane formation activator (tegoamine BDE).

[0116] When producing a polyurethane composition, 55 parts by weight of isocyanate component (B) are added to 100 parts by weight of polyol component A.

[0117] The composition is prepared by mixing component A and component B in a 20 ml sachet, followed by manual mixing. Mixing is continued for 10 seconds, as the sachet begins to heat up significantly after 8 seconds. The sachet is then opened, and the resulting composition takes on a stable, rigid form within 5 seconds, with the surface temperature of the coating reaching 55°C.

[0118] Example #7

[0119] The production of a medical product is illustrated in Fig.1-5.

[0120] According to one aspect of the claimed invention, a medical product containing the claimed polyurethane foam composition is an individual package - a sachet package, divided by a perforation line into two zones, one of which contains a polyol component A, and the other an isocyanate component B, made with the possibility of breaking this perforation and mixing the two zones, with the possibility of extruding the polyurethane foam composition and obtaining a polyurethane foam coating in the form of foam (bandage).

[0121] According to the main aspect of the present invention, the following is a method for producing a polyurethane foam composition contained in a medical product that is a convenient-to-use sachet package.

[0122] To apply the resulting foam to the wound, several steps must be taken beforehand, including stopping the bleeding and cleaning the wound. When applying the dressing, the wound should be moist and the intact skin around the wound should be dry and clean. If possible, position the wound horizontally to prevent the dressing from dripping.

[0123] Next you need to:

[0124] To tear the sachet, first twist the sachet in the direction of the arrow. Press on the sides of the sachet until the central seam breaks (see Fig. 1-2). Unfold the sachet to its original position.

[0125] Place your thumbs along the edges of the bag (see Fig. 3).

[0126] Intensively rubbing the chambers of the bag together (20-30 sec), stir the contents until the temperature noticeably rises and the volume increases (see Fig. 4).

[0127] Immediately tear off the top corner along the notch and apply the dressing to the wound, covering 2-2.5 cm of dry skin around the wound. Do not touch the dressing until it has completely hardened (4-6 minutes) (see Fig. 5).

[0128] According to the tests carried out on the polyurethane foam composition in accordance with the present invention, the following results were achieved.

[0129] It was established that the claimed polyurethane foam composition has improved properties, namely:

[0130] excellently protects wounds from secondary infection, has high elasticity, and sufficient air and vapor permeability, creating optimal conditions for wound healing. Good sorption capacity has been demonstrated, as demonstrated by the examples below.

[0131] Example #8

[0132] Determination of sorption capacity

[0133] This example illustrates the identification of improved sorption properties of the obtained polyurethane foam.

[0134] According to the sorption capacity testing method, polyol component A and isocyanate component B according to the present invention are mixed. After the polymerization process is complete, an accurate sample is weighed on a scale with a division value of 1.0 mg, the coating is compressed by hand and immersed in a container with water for (60.0 ± 1) min, at a temperature of (22 ± 4) °C, then weighed with an accuracy of 1.0 mg. The total sorption capacity is determined by the following formula:

[0135] A = (M2- M1) / M * 100%,

[0136] where

[0137] A - total sorption capacity (%),

[0138] M1 - weight of the attachment,

[0139] M2 - weight of the sample after being kept in water.

[0140] The results of determining the sorption capacity are shown in Table 1.

[0141] Example #9

[0142] Absorption capacity test

[0143] The absorption capacity of the polyurethane coating is tested using a method, the essence of which is to determine the ability of the material to absorb and retain water through filter paper in the vertical direction for certain periods of time (10 min, 30 min, 60 min, 120 minutes, 1 day, 3 days, 7 days).

[0144] For this, the polyol component A and the isocyanate component B are mixed. After the coating has formed into a dressing and has cooled to ambient temperature for 15-20 minutes, 3 samples with a diameter of 45±2 mm are cut from the product.

[0145] Each sample is weighed on filter paper pads of the same diameter. The samples are placed in three wells filled with water, with the fourth well left open to monitor the liquid level.

[0146] Maintains a constant liquid level by adding liquid through a cylindrical opening. The liquid level is monitored using the 4th cell.

[0147] After 10±1 min, the moistened sample is transferred to a Petri dish and weighed with an accuracy of 0.001 g.

[0148] Return the wetted sample back to the cell to continue testing.

[0149] The test procedure is repeated after 30±1 min, 60±1 min and 120±1 min, 1 day, 3 days, 7 days.

[0150] Absorption capacity (B) is determined by the weight gain of water relative to the initial mass of the sample and is calculated using the formula:

[0151] B = (M2 - M1) / M1

[0152] where M1 is the mass of the original sample,

[0153] M2 - wet sample mass.

[0154] Example #10

[0155] Study of the antibacterial properties of the obtained polyurethane foam composition

[0156] The antimicrobial activity was determined using the standard methodology approved by the Ministry of Health, the State Pharmacopoeia, Moscow, "Medicine," 1990, Issue 2, in the section "Methods of Microbiological Control of Medicines." The in vitro test data for the composition proposed according to the invention reflect the antimicrobial activity against test cultures of S. aureus and Ps. aeruginosae and are summarized in Table 3.

[0157] Results of the study of the clinical efficacy of external use of the composition proposed by the invention.

[0158] To determine the antibacterial properties, standard strains of Staphylococcus aureus and Pseudomonas aeruginosa, recommended by international standards for the study of antimicrobial properties, were used.

[0159] Bacterial cultures are inoculated and placed in a nutrient medium. Polyol component A and isocyanate component B are mixed according to the claimed invention and applied to the nutrient medium containing the bacterial cultures.

[0160] As shown in Table 3, the polyurethane foam composition according to the invention exhibits antibacterial properties against all tested cultures. This is an important aspect in the effective treatment of burns and other skin lesions, where the treatment process reveals an increase in microbial infection and the possibility of a secondary infection occurring.

[0161] Example #11

[0162] Results of the therapeutic effect of the applied polyurethane foam composition according to the present invention

[0163] Patient Zh., 67 years old, sustained burns on May 13, 2025, when he spilled a container of boiling water on himself while at his dacha. He did not seek medical attention for 24 hours and treated the wound with Panthenol spray. On May 14, 2025, he presented to the emergency room. On admission, the burn wounds were located on the left shin, primarily on the posterior surface, with an area of ​​approximately 500 sq. cm. They consisted of subepidermal blisters with straw-colored liquid contents, desquamated epidermis, and exposed pink, whitish-pink, and bright red dermis. Pain sensitivity in the area of ​​the burn wounds was preserved, and perifocal inflammation was not pronounced. The burn wounds were debrided, the subepidermal blisters were opened, and the remnants of the desquamated epidermis were removed. Aseptic gauze dressings with 10% Povidone-iodine solution were applied to the wound area.The patient was admitted to the adult burn unit. His left lower extremity was elevated using a Behler splint, and symptomatic therapy was prescribed. Laboratory tests on admission were normal. The patient's medical history includes: overnourished, BMI 34.6, and 10-year history of type 2 diabetes. The target HbA1C level is <7.5%. The disease is compensated. He has stage 2 hypertension, risk 4, and achieved target blood pressure of 130-140 / 80 mmHg.

[0164] On May 15, 2025, in the dressing room, the dressings were removed. Upon examination, the burn wound was revealed to have exposed pink, whitish-pink, and crimson dermis with translucent capillaries, reflecting damage within the epidermis and papillary dermis and corresponding to grades I-II in terms of thermal injury depth. Wound discharge was scant and serous. There were no signs of perifocal inflammation. Marginal and insular epithelialization were absent (see Fig. 6).

[0165] As a result, a decision was made to use the polyurethane foam composition according to the present invention as a multicomponent wound dressing made of polyurethane foam. Before applying the dressing, the wound surface was thoroughly cleaned with a 3% hydrogen peroxide solution and Prontosan solution and dried with blotting motions using a sterile gauze pad.

[0166] The wound dressing consists of two components located in compartments of a specially designed reactor package, separated by a central seam. Application of the polyurethane foam composition, consisting of components A and B, consisted of preparing the coating for application by twisting the reactor package until the central seam ruptures and mixing the two components together by vigorously rubbing the chambers with the contents. During the process of mixing the components of the composition, a noticeable warming of the package and a significant increase in its volume were observed, which determined the readiness of the coating for use. The package was opened immediately, according to the instructions, by tearing off the corner marked with a notch. Immediately after opening, a milky-white foamed mass was abundantly released from the package, which was evenly applied to the prepared wound surface, capturing 2-2.5 cm of intact skin along the perimeter of the wound (see Fig. 7).

[0167] Within 4-6 minutes after application, complete hardening of the wound dressing on the wound surface was observed, like thickened foam, and strong adhesion to the wound.

[0168] From May 15, 2025 to May 19, 2025, a visual assessment of the wound dressing condition was performed. The dressing structure remained unchanged, and no deformation or delamination was observed.

[0169] On May 19, 2025, in the dressing room, the dressing was removed. Removal of the dressing was performed by gentle peeling and did not cause trauma to the wound surface. Significant improvement was noted: the wound is clean and dry, no purulent discharge is present, and there are signs of active insular and marginal epithelialization (see Fig. 8).

[0170] Visually, the removed dressing was heavily soaked with wound fluid, but the surface in contact with the wound was dry, indicating the dressing's high absorption properties. A control sample of wound fluid was collected for bacteriological testing. The dressing was reapplied to the wound surface according to the product instructions.

[0171] May 22, 2025, in the dressing room, the dressing was removed. Upon examination, complete epithelialization of the wound surface was noted. Removal of the dressing was performed by gentle peeling and did not result in trauma to the epithelialized surface (see Fig. 9).

[0172] On May 23, 2025, the patient was discharged for outpatient treatment with restored skin.

[0173] As a result of the above clinical studies of the effectiveness of the declared polyurethane foam composition, its antibacterial properties and an increase in the absorption capacity and sorption capacity of the resulting foam were noted, which in turn led to an increase in sorption capacity and, as a consequence, to effective treatment, allowing for a reduction in wound healing time.

[0174] The findings of the above studies showed the following.

[0175] Analysis of the obtained data, as well as their comparison with the data according to the prototype, showed that the claimed invention solves the following technical problems:

[0176] - increasing the absorption properties of the resulting material by increasing the number of open pores (above 70%), which allows increasing the absorption capacity of the dressing;

[0177] - determination of the optimal reaction temperature (39°C) while reducing the gelation time and structuring of the dressing by using the optimal ratio of all the declared components, which in turn leads to the elimination of additional pain in patients;

[0178] - reduction of the concentration and composition of chemical components (up to 7 components), resulting in a reduction in the cost of the target product;

[0179] - ensuring wound sealing due to adhesion to healthy skin and high congruence with the wound relief;

[0180] - facilitates wound care by applying a single polyurethane foam covering;

[0181] - has high elasticity and sufficient air and vapor permeability, which allows creating optimal conditions for wound healing;

[0182] - perfectly protects the wound from secondary infection;

[0183] - has high absorption capacity according to Table 1.

Claims

1. A polyurethane composition intended for the treatment of burns and healing of wounds of various etiologies, containing: component A, which is a mixture of components in the following ratio in the composition, mass parts: - high molecular weight trifunctional polyester based on propylene and ethylene oxides with a molecular weight of 5000-6000 units. 100 - foaming agent: water, distilled 3,0-5,5 - foam opener: high molecular weight trifunctional polyester 0,25-2,5 - emulsifier, foam stabilizer: triethanolamine (TEA) 0,8-1,4 - foam hardener: triethylenediamine (TEDA) 0,1-1,2 - chain extender: diethanolamine (DEA) 0,2-1,5 - foaming catalyst: dimethylethanolamine (DMEA) 0,15-2,4 - urethane formation activator: tegoamine BDE 0,1-0,4, and component B, which is an isocyanate component, namely aromatic diphenylmethane diisocyanate - 30-50 mass parts.

2. Use of the composition according to item 1 for obtaining a polyurethane foam coating in the form of a dressing for the treatment of burns and wounds of various etiologies.

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