JP2006333897A - Interactive wound care system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optimum gas and liquid environment for enhancing wound healing, improving patient comfort and reducing costs by providing an occlusive covering and interaction with a wound during the healing process. <P>SOLUTION: A method of forming an in situ film dressing on animal tissue is provided, which comprises preparing an application liquid including a polyalkylene carbonate, applying the application liquid to animal tissue and forming a film dressing on the animal tissue. A material for forming a film dressing on animal tissue is also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wound care system comprising a unique bandage and a composition comprising the bandage.

  The present invention relates to wound care that covers both an external wound (such as skin) and an internal wound (such as an organ). Wound care has many aspects, both medical and economic. The shorter the treatment period, the more economical the procedure and the greater the patient comfort. Treatment and nursing costs are nearly ten times higher than article costs. Some of the complications that increase the duration of treatment are long periods of infection, suboptimal wound care dressings, healing and suturing. These are affected by the wound care system used. The most common wound dressings were gauze and tape. Subsequently, a multilayer system was designed with a film backing. Liquid bandages that provide film coverage of the wound have also been suggested. While these wound dressings provide the desired protection in part to the wound, they do not provide an optimal environment for enhancing wound healing and minimizing scarring.

  Gauze bandages may not completely protect wounds from water, bacteria, dust, external oxygen and other foreign objects. Gauze can stick to the wound, causing damage to the wound during bandage changes, increasing the probability of infection and extending the healing period.

  Multi-layer dressings are improved compared to gauze dressings, but can be cramped and bulky, making it easier to form a passageway that allows bacteria and foreign objects to enter the wound. These bandages typically have a layer that absorbs wound exudate and must be replaced during wound healing. Injury may be caused by the bandage sticking to the wound. These multilayer bandages may have a film backing. Typically, polyurethane is used. This does not provide the desired barrier to external oxygen to protect the wound from external oxygen in the early stages of healing. Some multi-layer bandages may provide a somewhat lower level of oxygen barrier simply due to the bandage and its thickness.

  Conventionally suggested liquid bandages are usually polymer solutions dissolved in organic solvents. The solution is applied directly to the wound, i.e. applied, and the solvent evaporates and / or precipitates, or the solution solidifies in situ, leaving a film over the wound. These films may be nitrocellulose polymers or cyanoacrylic acid. These films do not provide oxygen barrier properties to the wound site. Since these are not elastomers, they do not impart elasticity and resilience to the film. Because of their high softening temperature, the film cannot flow as a result of skin / body temperature. Nitrocellulose films tend to form cracks when placed over bending and extending sites such as the base of the thumb or other moving anatomical body parts. These cracks then destroy the protective covering of the wound. These films can also give off undesirable chemical odors. Any of the above wound dressings generates an oxygen barrier, elasticity and resilience, compatibility with the site, i.e. low glass transition temperature, carbon dioxide and water to improve the property of tightly covering the site. Not all of the desired combinations of properties necessary to enhance wound healing, such as not sticking to the wound by enzymatic degradation of the polymer at the site of the wound.

  Polycarbonate is listed as one of many polymers used as films. Polycarbonate has no effect as disclosed in this application. Polycarbonate is a different polymer than polyalkylene carbonate.

In a wound, a new blood vessel grows from an oxygen-rich zone toward a low oxygen zone (Non-patent Document 1). Normal tissue has an oxygen partial pressure of about 40 mmHg. Angiogenesis is stimulated in a relatively low oxygen state of about 1-10 mmHg (Non-patent Documents 2-4).
Knightton D et al., “Partial oxygen pressure regulates the expression of angiogenic factors by macrophages.” Science, 1983, 221, 1283-5. Hunt TK et al., “Wound Microenvironment”, Cohen IK et al. (Eds), “Wound Healing: Biochemical and Clinical Aspects”, Philadelphia, WB Saunders, 1992, 274-281. Pai MP et al., "Effect of different oxygen partial pressures on healing of open wounds", Gynecol Obst 1972, 135, 756-758. Storch, TG et al., “Oxygen levels modulate the proliferative response of human fibroblasts to serum and growth factors.” Exp Cell Res, 1988, 175, 317-325.

  A bandage that is impermeable to external oxygen causes the angiogenesis to proceed most rapidly. Early oxygen deficiency and late oxygen supply lead to healing. Lowering the pH of the wound also contributes to angiogenesis. The low pH is maintained by preventing the wound tissue from losing all of its carbon dioxide.

Some of the challenges associated with some wound care systems in prior art methods include:
The oxygen gas environment around the wound is not optimal (relatively high) as a result of the wound dressing allowing external oxygen to enter the wound area at an early stage;
・ There is no appropriate (sufficient) humidity,
Bacteria invading the wound area due to poor adhesion and / or covering of the bandage and film covering that forms cracks, passages and wrinkles leading to the wound due to lack of elasticity;
The exudate removal is not optimal in connection with inadequate water vapor transmission from the wound;
・ Insufficient mechanical pressure on the wound,
・ Contamination of gauze bandage due to handling,
-Injury to healing cells by gauze bandages that attach to wounds and cause injury, particularly damage by peeling epithelial cells and interfering with healing during bandage exchange.
・ A hard bandage that may be flexible but does not have elasticity to fit the body shape when bent and stretched,
Loss of carbon dioxide from wound tissue, leading to high pH and alkalosis,
・ Sensitivity of skin to tape causing rash,
・ Chemical odors of different degrees
And • other film bandages are unable to incorporate all the necessary key properties into a single film.

  The present invention provides an interactive wound care system that meets the above problems. Our system provides an occlusive covering and interaction with the wound during the healing process to deliver optimal expectations and a fluid environment to improve wound healing, improve patient comfort and reduce costs. provide.

Summary of the Invention When the wound covering allows the necessary concentrations of oxygen, humidity, exudates, carbon dioxide and bacteria around the wound, wound healing is enhanced and scar formation is minimized.

  A recently developed family of polymers called polyalkylene carbonate (PAC) is utilized to design the optimal environment inside and around the wound. These polymers are produced by reacting carbon dioxide with epoxides (Inoue S, “Organic and Bio-Organic Chemistry of Carbon Dioxide”, Halted Press, New York, pp 167-176, 1982). The resulting properties of the polymer will vary depending on the epoxide selected.

  Polymers with properties ranging from soft elastic polymers with low glass transition temperatures (15 ° C. to 25 ° C. to 40 ° C.) to hard rigid polymers with high glass transition temperatures of eg 132 ° C. can be produced. . Polymers with intermediate properties can be produced by chemical means (terpolymer) and physical means (blends). These polymers may be selected to provide a different degree of oxygen barrier that separates the wound from ambient oxygen and prevents carbon dioxide transmission from the wound for enhanced wound healing.

  Films made of these polymers adhere to the skin, forming a barrier to external dust, water and bacteria, allowing water vapor transmission from the wound, and excess exudates and bacteria from the wound by evaporation. Go out to reduce wound pressure and infection.

  These films do not adhere to the wound, thus allowing frequent bandage changes without disturbing the normal healing process of the wound. In addition, these polymers provide solutions of one or more polyalkylene carbonates and one or more solvents, suitable films for a number of biologically acceptable solvents, It makes it possible to design a foam or gel composition. These polymers are sometimes produced as water based emulsions. These solutions or emulsions may be applied around the wound with a brush or spray to form a protective and interactive film that is compatible with wound healing. Other methods of application can be used, such as gels from extruded tubes, melt formed films, squeegees, or solutions spread with a spatula. Other adhesives may be dissolved or dispersed in these solutions to allow the design of chemical medical systems that optimize wound healing. Examples of drugs that can be added to the polyalkylene carbonate solution include well-known antibacterial agents (such as erythromycin and clindamycin), steroids (such as clovestazole, triamcinolene, and fluocinonide), and antifungal agents (Penlac). , Griseofulvin and terbinafine (Lamisil, etc.), immunomodulators, antimicrobial agents, anti-acne agents and anti-psoriatic agents. The wound is first pretreated with a drug or the like, and then a protective film coating or the like may be applied by spraying. The object of the present invention is to solve the problems of conventional dressings by uniquely designing an appropriate polyalkylene carbonate polymer or a combination of polyalkylene carbonate polymers, which is unique to other wound care dressings. It is to meet the challenges.

One or more physicochemical properties of this family of selectively available polyalkylene carbonate polymers are:
・ Transparency, amorphousness, thermoplasticity,
The glass transition temperature is in the range of about 15 ° C to about 132 ° C;
・ Excellent skin adhesion and does not adhere to wounds.
・ It is a soft elastic polymer with high resilience against hard engineering polymer.
・ Decomposed mainly into carbon dioxide and water by enzymatic decomposition or combustion,
・ Excellent oxygen barrier,
・ Water vapor is semi-permeable,
・ Inexpensive,
・ Odorless and quick drying,
It is soluble in a wide range of solvents from low boiling point solvents to high boiling point solvents,
The glass transition temperature of polyethylene carbonate is as low as 25 ° C., for example,
Softening with skin and whole body temperature to promote a soft, flexible and elastic bandage to facilitate adaptation to the moving body shape;
・ Oxygen permeability can be controlled,
The barrier to external water, dust and bacteria,
That it can be produced as an aqueous emulsion, and
・ The film has excellent self-adhesiveness.

DETAILED DESCRIPTION OF THE INVENTION To utilize the present invention, one or more of the polyalkylene carbonate polymers are applied in a liquid form (eg, to cover a wound), ie, applied to an animal tissue. . Thus, for example, the polyalkylene carbonate is soluble in one or more biocompatible solvents. Some of the available solvents are methylene chloride, dichloroethane, propylene carbonate, dimethylformamide, N-methylpyrrolidone, acetone, ethyl acetate, tetrahydrofuran, methyl ethyl ketone and other ketones, esters, ethers, and the like. The polymer concentration varies depending on the delivery system.

  As a general rule, it is preferred to use polyalkylene carbonates in which the alkylene moiety contains from about 2 to about 9 carbon atoms. It is particularly preferred to use a polyalkylene carbonate in which the alkylene moiety is one of ethylene, propylene and butylene.

  Some of the preferred solvents include methylene chloride and acetone, but generally alcohols and other well-known organic solvents are available. When the polyalkylene carbonate is polyethylene carbonate, methylene chloride is preferably used as the solvent, but when the polyalkylene carbonate is polypropylene carbonate, acetone is preferably used as the solvent.

  The wound is first cleaned and then any of the following application methods are used.

  When spray cans (aerosols) or bottle sprays are used, lower concentrations of polymer are used to give the proper viscosity for spraying and filming on and around the wound. This concentration will also vary depending on the solvent selected and the molecular weight. The polymer concentration for this application is usually in the range of about 5% to about 35% by weight solution.

  When a brush, cotton swab (Q-tip), eye-dropper or stick is used, a medium concentration polymer with an appropriate viscosity is used to prevent the solution from flowing out of the wound. The polymer concentration for this application is usually in the range of about 5% to about 50% by solution weight concentration.

  If a gel or extruded tube is used, the polymer concentration may be higher. The gel is applied directly and applied to form a film on and around the wound. The polymer concentration for this application is usually in the range of about 20% to about 60% by weight of the gel.

  When a molten film taken from a molten film former is used, the polymer concentration is, for example, within about 100% by weight of the polymer excluding all additives, such as absorbents, humectants, drugs, plasticizers, There may be a relatively high concentration.

  If an emulsion, such as an aqueous emulsion, is used, the polymer concentration may be maximized based on other chemicals throughout the system. The polymer concentration may be in the range of about 10% to about 60% by weight based on the emulsion.

  Films produced by any of the above methods have excellent self-adhesive properties. Thus, these films can completely cover the periphery of certain body parts and become self-adhesive. Spraying over the film can provide greater protection around the wound by providing a perfect seal around the oddly shaped (irregularly shaped) wound of the body.

  Using polyalkylene carbonate with excellent oxygen barrier properties, low Tg at about 25 ° C, high stretch recovery, flexibility and elasticity gives excellent conformity and protection to irregular body shapes . The low Tg allows skin temperature to further soften the polymer and make it more conformable with irregular shapes, increasing patient comfort and providing great protection of the wound. The film thickness can be from about 0.25 mil to greater than about 3.0 mil, for example, about 3.5 mil.

  In the early stages of healing of certain types of wounds, ambient oxygen is undesirable. By blocking external oxygen and allowing oxygen inside the blood vessel to assist wound healing, the wound heals more quickly and with less scar formation. Prior art patents did not recognize this important role of oxygen scavenging. Prior art patents, on the contrary, disclosed films that are “suitable exchange” of oxygen and / or “semi-permeable” for oxygen. Kay et al. US Pat. No. 5,713,842 discloses that “oxygen, water vapor and other gases can freely diffuse through the molecular matrix” and that polyurethane films are preferred. Tipton et al., US Pat. No. 5,725,491, “It is preferred that the size and number of pores in the film dressing facilitate the diffusion of nutrients, oxygen, water and biologically active reagents. ".

  Examples in the prior art patents of usable polymers do not include polyalkylene carbonates.

Wounds treated with oxygen permeable films have a slow recovery rate. An occlusive dressing has a lower infection rate than a non-occlusive dressing. Thus, by using a polyalkylene carbonate film as a suitable polymer we will combine the following features:
・ Oxygen barrier
・ Water resistance against external water
・ There is elasticity to make the film not cracked by the movement of the surface,
・ Has good shielding properties
・ It is easy to apply and is a one-component system that can be sold over-the-counter.
-Good skin adhesion that does not allow bacteria and foreign substances to enter,
・ Excellent self-adhesiveness to completely cover the periphery and to make multiple layers if necessary,
The film is transparent for observation of the wound, if desired,
The polymer can be enzymatically degraded to form carbon dioxide and water at the wound / film surface interface to enhance bandage removal and wound healing power;
-Oil resistance, acid and alkali resistance so as not to be affected by oils or liquids in the body,
・ Wear resistance so that it is not easily damaged by external force.
Contain chemical / medical additives for better binding, dispersibility or solubility,
To reduce odor and promote healing by allowing frequent bandage changes without sticking to the wound and damaging wound healing cells.
The film is water vapor permeable to assist in the removal of exudates and bacteria;
Be semi-permeable to carbon dioxide to maintain a low pH and prevent alkalosis,
・ When methylene chloride is used as a solvent, the film must be dry and no odor will remain.
・ The shelf life is infinite, and
-It must be an inexpensive wound covering.

  A preferred method of use of the present invention is to produce a solution comprising from about 10% to about 15% by weight concentration of a polyethylene carbonate solution in methylene chloride. The wound is washed or pretreated and then dried. The polymer solution is then coated with a brush or spray. Since the boiling point of the solvent is as low as 39.7 ° C., for example, the drying process takes several minutes. The skin body temperature is about 33 ° C. and the body temperature is about 37 ° C., which facilitates evaporation of the solvent and flow of the polymer, which has a glass transition temperature of about 20-25 ° C. The process of wound healing is observed through a transparent film. If a bandage change is necessary, the film is easily removed and a new film is applied. The film is removed when the healing is complete.

  In certain other types of wounds, or in later stages of certain wounds, polypropylene carbonate can be used, as external oxygen may be desirable, but it is not suitable as an oxygen barrier. It is not so good. Intermediate properties to optimize wound healing, depending on the type of wound, by blending polypropylene carbonate and polyethylene carbonate either physically or chemically (terpolymer) Can be obtained.

  There is no other family of polymers that can be integrated with this unique family of physical / chemical properties that can be obtained using this new family of polymers, polyalkylene carbonates. Polyalkylene carbonate can be “tailored” to fit this application, providing an overall healing system that promotes wound healing, reduces scar formation, increases patient comfort and reduces costs To do.

Wound healing is a complex process. Significant and valuable medical knowledge that can improve wound care has developed. Polyalkylene carbonate polymers have a wide range of properties that can be effectively utilized with modern medical knowledge to produce a new generation of wound dressings. As new wound care knowledge develops, it has the potential to be tailored to meet new medical needs.

Claims (21)

  In-situ film dressing on animal tissue comprising preparing an application liquid comprising polyalkylene carbonate, applying the application liquid to animal tissue, and forming a film on the animal tissue How to form.   The polyalkylene carbonate is placed in a liquid state by heating to at least the same temperature as its glass transition temperature and extruding the liquefied polyalkylene carbonate to the animal tissue. Method.   The polyalkylene carbonate forms a suspension in a biocompatible solvent, applies the liquid polyalkylene carbonate to animal tissue, and evaporates the biocompatible medium, The method of claim 1, wherein the method is disposed in a liquid state.   The polyalkylene carbonate is in a liquid state by forming an emulsion in a biocompatible solvent, applying the liquid polyalkylene carbonate to animal tissue, and evaporating the biocompatible medium. The method of claim 1, wherein:   The polyalkylene carbonate forms a polyalkylene carbonate solution in a biocompatible solvent, applies the liquid polyalkylene carbonate to animal tissue, and evaporates the biocompatible solvent. The method of claim 1.   The method of claim 1, wherein the alkylene portion of the polyalkylene carbonate contains up to 9 carbon atoms if two.   The method of claim 1, wherein the alkylene portion of the polyalkylene carbonate is selected from the group consisting of ethylene, propylene, and butene.   6. The method of claim 5, wherein the polyalkylene carbonate concentration in the solution is from 5% to 50% by weight of the solution, and the solution is applied over the animal tissue.   The polyalkylene carbonate concentration in the suspension is from about 10% to about 60% by weight of the suspension, and the suspension is applied over the animal tissue. The method described in 1.   The method of claim 1, wherein the liquid polyalkylene carbonate comprises a drug.   11. The method of claim 10, wherein the agent is selected from the group consisting of antibacterial agents, steroids, antifungal agents, immunomodulators, antimicrobial agents, steroids, anti-acne agents and anti-psoriatic agents.   A liquid polyalkylene carbonate having a glass transition temperature from about 15 ° C. to about 40 ° C., wherein the liquid polyalkylene carbonate adheres to the animal tissue and forms a film dressing on the animal tissue. Material.   13. The material of claim 12, wherein the polyalkylene carbonate is placed in a liquid state by being heated to at least the same temperature as its glass transition temperature.   13. The material of claim 12, wherein the polyalkylene carbonate is placed in a liquid state by forming a suspension of polyalkylene carbonate in a biocompatible medium.   13. The material of claim 12, wherein the polyalkylene carbonate in liquid form is a solution in a biocompatible solvent.   16. The material of claim 15, wherein the alkylene portion of the polyalkylene carbonate is selected from the group consisting of ethylene, propylene and butene.   The material of claim 15, wherein the alkylene portion of the polyalkylene carbonate is ethylene and the biocompatible solvent of polyethylene carbonate comprises methylene chloride.   16. The material of claim 15, wherein the alkylene portion of the polyalkylene carbonate is propylene and the polypropylene carbonate biocompatible solvent comprises methylene chloride.   The polyalkylene carbonate is polyethylene carbonate having a glass transition temperature from about 20 ° C. to about 25 ° C., the biocompatible solvent is methylene chloride, and the polyethylene carbonate is the solution 16. The material of claim 15, wherein the material is present in the solution at a concentration by weight of from about 10% to about 15%.   20. A material according to claim 19, comprising a drug. 21. The material of claim 20, wherein the agent is selected from the group consisting of antibacterial agents, steroids, antifungal agents, immunomodulators, antimicrobial agents, steroids, anti-acne agents and anti-psoriatic agents.