JPH034227B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to wound dressings. In particular, the present invention relates to a wound dressing comprising a microcapsule layer and a collagen film layer supporting the microcapsule layer. The wound dressing of the present invention is useful as an external preparation for treating burns, skin extraction wounds, skin abrasion wounds, traumatic skin defect wounds, and the like. [Prior Art and Problems] Traditionally, when administering hormones to treat injuries, etc., they were supplied through the circulatory system through injections, but because they were not applied locally to the affected area, they were not as effective. Additionally, because it circulates throughout the body, there is a possibility of side effects due to excessive intake. Therefore, recently, it has been incorporated into creams and the like and applied directly to the affected area for its effect. However,
Hormones may leak from the affected area at an early stage, and this cannot be prevented.
For this reason, it is necessary to apply cream to the affected area many times, and this complicated and time-consuming process has many inconveniences, including the risk of causing problems such as bacterial infection. On the other hand, in cases where there is particularly extensive loss of skin tissue due to skin diseases or skin wounds such as burns, skin harvest wounds, dermabrasion, and traumatic skin loss wounds,
Rapid tissue repair is desired because bacterial infection and excessive outflow of body fluids in the affected area can put life at risk. Autologous transplantation is currently considered the best method for treating such affected areas, but it is extremely difficult in cases where the skin defect is widespread, and even if it is possible to apply it, it may not last for a long period of time. It is necessary to repeat the transplant several times. Therefore, instead of autografting, there is a need to develop a wound dressing that temporarily or permanently covers the affected area to prevent bacterial infection and the outflow of body fluids, as well as to promote tissue repair by proliferating tissue cells. desired. [Object of the Invention] An object of the present invention is to provide a wound dressing that prevents bacterial infection in the affected area and outflow of body fluids, and promotes tissue repair by proliferating tissue cells. [Configuration of the Invention] The object of the present invention is achieved by the following configuration. (1) A wound dressing consisting of a microcapsule layer containing cell growth factors incorporated into a coacervate structure consisting of denatured collagen and mucopolysaccharide, and a sheet-like collagen film layer supporting the microcapsule layer. (2) The wound dressing according to item 1, wherein the cell growth factor is a hormone related to cell growth. (3) The wound dressing material according to item 2, wherein the hormone is insulin or hydrocortisone. (4) The wound dressing according to item 1, wherein the cell growth factor is epidermal growth factor (EGF), urogastrone, or platelet-derived growth factor (PDGF). (5) Denatured collagen heats collagen from 37℃ to 90℃.
The first, which is obtained by heat denaturation in the range of °C.
Wound dressings as described in Section. (6) The wound dressing material according to item 1, wherein the mucopolysaccharide is an acidic mucopolysaccharide. (7) The wound dressing according to item 6, wherein the mucopolysaccharide is chondroitin sulfate, heparan sulfate, dermatan sulfate, hyaluronic acid, or heparin. (8) The wound dressing according to item 7, wherein the mucopolysaccharide is chondroitin-6-sulfate. (9) The wound dressing material according to item 1, wherein the collagen film is an oriented fiber. (10) The thickness of the collagen film is 5 to 500 μm.
2. The wound dressing according to claim 1. (11) The wound dressing material according to item 1, wherein the collagen film is porous. Hormones that are directly or indirectly involved in cell proliferation can be used as cell growth factors. Insulin and hydrocortisone can be used as hormones related to cell growth. In addition, cell growth factors
Epidermal growth factor (EGF), urogastrone, and platelet-derived growth factor (PDGF) can also be used in trace amounts. Denatured collagen is obtained by treating oxygen-treated collagen derived from bovine dermis with acid or alkali, followed by treatment with protease or pepsin to eliminate the telopeptide at the terminal end of the molecule, and is used as a raw material. This oxygen-treated collagen is swollen with water to form an oxygen-treated collagen aqueous solution,
This is thermally denatured by heating to perform a denaturation treatment. Thermal denaturation of collagen occurs around 37°C, so it is preferable to heat it to 40°C or higher to ensure denaturation. Heating above 90° C. should be avoided to prevent boiling of the aqueous solution and to prevent irreversible denaturation of the collagen from occurring and interfering with coacervate formation. A suitable heat denaturation treatment is to hold at a temperature around 60°C for several hours. If collagen is used as it is, microcapsules cannot be produced because the coacelvation phenomenon does not occur. By performing such a modification treatment, the coacervation phenomenon, that is, the formation of a coacervate structure, becomes possible for the first time. In addition, coacelvation is difficult to occur only with denatured collagen, which is a polycation, so
Add acidic mucopolysaccharides as polyanions. The mucopolysaccharide used for microcapsule production is
Specifically, chondroitin-6-sulfate, which is a type of acidic mucopolysaccharide, is used. Other mucopolysaccharides that can be used include heparan sulfate, dermatan sulfate, hyaluronic acid, and heparin. When producing microcapsules, the above enzyme-treated collagen was soaked in distilled water for one day and night to swell, obtain a dilute aqueous solution, and adjust the collagen denaturation temperature (37
℃) and held for a predetermined period of time to cause thermal denaturation. The temperature for this modification is preferably in the range of 37°C to 90°C. Next, create a dilute aqueous solution of mucopolysaccharide and chondroitin sulfate, add this to the previously created dilute aqueous solution of denatured collagen kept at 37°C or above at a temperature above the denaturation temperature of collagen, and adjust the PH. When stirred, coacervate is produced. In this case, if a cell growth factor is mixed, the cell growth factor will be incorporated into the produced coacervate. All mixing, stirring, and pH adjustment operations should be performed at a temperature of 37°C or higher. It has been found that coacervate droplets composed of such a denatured collagen-chondroitin sulfate system take up cell growth factors such as insulin and hydrocortisone. The amount of intake depends on the amount of preparation, and when the amount of preparation is small, it is possible to take in about 80% of the amount of preparation, but when the amount of preparation is large, there is a limit to the amount of absorption, and it becomes saturated at a certain amount. It ends up. The collagen used in the collagen film layer is oxygen-treated in the same manner as above, but unlike the above-mentioned denatured collagen, it is not thermally denatured.
The collagen film is desirably made into oriented fibers or crosslinked in order to suppress decomposition by oxygen such as collagenase. In order to obtain fibers with orientation, for example, a collagen solution is mixed with a balanced salt solution such as Hank's solution at a weight ratio of about 1:1 to 5, preferably 1:2, heated to 37°C, and mixed with a balanced salt solution such as Hank's solution. ~10 days preferably 3
Incubate for days. For crosslinking, aldehydes such as glutaraldehyde, formaldehyde, and glyoxal; diisocyanates such as hexamethylene diisocyanate and diphenylmethane isocyanate; dianamide, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride; Crosslinking is carried out using a crosslinking agent such as carbodiimide, preferably diisocyanate, particularly hexamethylene diisocyanate. Further, from the viewpoint of preventing leakage of body fluids and bacterial infection, it is preferable that the collagen film is made porous to have air permeability. To be versatile, approximately
It can be obtained by further air-drying the collagen incubated at 37° C. to dryness, washing excess neutral salts with water, and drying. Air drying was performed in a sterile room or clean bench. The thickness of the collagen film can be adjusted by adjusting the collagen solution concentration and volume. The film thickness is preferably about 5 to 500 μm, more preferably about 5 to 500 μm, in view of the permeability of the volume. The microcapsules and collagen film produced as described above are laminated by dropping a microcapsule solution onto the collagen film to impregnate the entire film, thereby obtaining the wound dressing of the present invention. Note that this operation is performed in a sterile room or a clean bench. Example 1 (1) Preparation of hydrocortisone-containing microcapsules Commercially available oxygen-treated collagen [trade name: Atelocollagen (powder), Kouken Co., Ltd.
product] in distilled water (or deionized water). At this time, the concentration of enzyme-treated collagen is
When made into a dilute aqueous solution of about 0.1 to 0.5% by weight,
It is suitable for producing coacervate, and more preferably around 0.3% by weight. The resulting enzyme-treated collagen aqueous solution is placed in an oven and heat-treated to denature it. It is stored for a certain period of time in an oven set at a predetermined temperature, but the most suitable processing temperature for coacervate production is:
The temperature is around 60℃. Processing times range from about 2 hours to several hours. This heat treatment denatures the collagen, but the denatured collagen is kept at a temperature above the denaturation temperature until it is subjected to the next mixing operation. On the other hand, as a material corresponding to denatured collagen as a polycation, an H ⁺ form of chondroitin-6-sulfate (chemical name: chondroitin sulfate C, manufactured by Wako Pure Chemical Industries, Ltd.), which is a polyanion, is prepared. Chondroitin-6-sulfate is usually referred to as sodium chondroitin-6-sulfate ^.
It is often commercially available as a type, but it is used by converting it into the H ⁺ form in a solution using a cation exchange resin. The obtained denatured collagen aqueous solution and chondroitin-6-sulfuric acid aqueous solution were each passed through a 0.45 μm filter to remove impurities. Since hydrocortisone is insoluble in water, an ethanol solution containing hydrocortisone is prepared. The concentration of this hydrocortisone is
Approximately 0.05% by weight is desirable. Next, the three types of aqueous solutions obtained in this way are mixed at a temperature above the denaturation temperature. The mixing ratio at this time is chondroitin contained in the mixed aqueous solution.
The weight of 6-sulfuric acid is adjusted to 10 to 30% by weight of the total weight of denatured collagen and chondroitin-6-sulfuric acid. The amount of hydrocortisone to be prepared is
It can be varied as necessary to obtain the desired amount of hydrocortisone uptake.
That is, FIG. 1 is a graph showing the amount of hydrocortisone taken into microcapsules with respect to the amount of charged hydrocortisone. Determine the amount of hydrocortisone to be added to obtain the desired amount from this graph, and add that amount of hydrocortisone to the mixture. After thoroughly mixing this mixture, 1N
Adjust the PH using HCl. This mixed aqueous solution
When the pH is lowered to a weak acidity of about 3 to 6 and the mixture is stirred and mixed, it becomes cloudy, a coacervation phenomenon occurs, and coacervate containing hydrocortisone is precipitated. This coacervate is stabilized by a coacervate film hardening treatment method such as formalin treatment,
Microcapsules incorporating hydrocortisone were obtained. (2) Test of sustained release properties of microcapsules 20 ml of the hydrocortisone-containing microcapsules prepared in 1 above are placed in a 60 mm shear dish and air-dried in a clean bench. The membrane of the dried hydrocortisone-containing microcapsules (hydrocortisone content 10 μg/ml) was
Place in a mm jar and add 20 ml of physiological saline. The shear dish was kept at room temperature, and samples of the solution were taken over time to quantify the hydrocortisone content. The results are shown in FIG. It has been found that the hydrocortisone-incorporated microcapsules according to the present invention can release drugs over a long period of time and can maintain drug efficacy over a long period of time. (3) Preparation of collagen film A commercially available collagen solution [trade name: Atelocollagen, manufactured by Koken Co., Ltd., 0.3%] and 1.5 times concentrated Hank's solution were mixed in a 1:2 ratio (volume).
and mixed at below 4°C. The resulting mixture was poured into a styrene container and averaged there, and then immediately transferred to an incubator at 37°C and incubated for 3 days to solidify into agar-like form. This treatment turns collagen into oriented fibers. This agar-like collagen solution was air-dried in a clean bench to dryness. This resulted in a white film containing excess neutral salt. Further washing with water to remove excess neutral salt gave a translucent collagen film. The thickness of the collagen film can be easily changed by changing the concentration and volume of the collagen solution poured into the styrene container. (4) Collagen film permeability test The collagen film obtained in 3 above was evaluated for solute permeability. Film thickness 11μ
Glucose (molecular weight: 180), vitamin B ₁₂ using commercially available dialysis cells of m, 20 μm and 40 μm.
(molecular weight: 1355), inulin (molecular weight: 5200), and bovine serum albumin (molecular weight: 66000).

[Table] (5) Preparation of wound dressing The collagen film obtained in 3 above (film thickness 11 μm) and the hydrocortisone-containing microcapsules obtained in 1 above or the insulin-containing microcapsules obtained in 1 above. prepare. The concentration of growth factors contained in microcapsules is 1 μg/ml for hydrocortisone and 10 μg/ml for insulin.
g/ml is preferred. The microcapsule solution was slowly dripped onto the collagen film until the entire collagen film was impregnated with microcapsules. When the collagen film impregnated with the microcapsule solution was freeze-dried, a collagen film laminated with cell growth factor-containing microcapsules was obtained. Incidentally, all operations in the Examples are performed in a sterile room or a clean bench. [Effects of the Invention] The present invention provides a wound dressing comprising a microcapsule layer and a collagen film layer supporting the microcapsule layer. Since the microcapsule layer consists of microcapsules in which cell growth factors are coated with collagen and mucopolysaccharides, cell growth factors gradually leak out, and by containing cell growth factors, they can be used for a long period of time. The formation of the granulation layer and epidermis is promoted over time. Furthermore, by using a complex of skin-derived collagen and mucopolysaccharide, it has excellent affinity for the skin and other body parts. Further, since the collagen film layer is modified into oriented fibers or cross-linked, it is possible to suppress decomposition by enzymes such as collagenase. Furthermore, since the material is porous and has breathability, it is possible to minimize the occurrence of bodily fluid leakage, bacterial infection, etc. By combining the above-described microfilm layer and collagen layer, the wound dressing material according to the present invention temporarily or permanently covers the affected area to prevent bacterial infection and loss of body fluid, and to promote tissue cell proliferation. and can promote tissue repair. Therefore, as an alternative to autotransplantation, burn injury,
It can be applied to wounds such as skin harvest wounds, skin abrasion wounds, and traumatic skin defect wounds.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the amount of hydrocortisone charged and the amount of hydrocortisone incorporated into microcapsules. FIG. 2 is a graph showing sustained release of hydrocortisone from microcapsules.

Claims (1)

[Scope of Claims] 1. A wound dressing comprising a microcapsule layer containing a cell growth factor incorporated into a coacervate structure consisting of denatured collagen and mucopolysaccharide, and a sheet-like collagen film layer supporting the microcapsule layer. 2. The wound dressing according to claim 1, wherein the cell growth factor is a hormone related to cell proliferation. 3. The wound dressing material according to claim 2, wherein the hormone is insulin or hydrocortisone. 4. The wound dressing according to claim 1, wherein the cell growth factor is epidermal growth factor (EGF), urogastrone or platelet-derived growth factor (PDGF). 5 Denatured collagen heats collagen from 37℃ to 90℃.
The wound dressing material according to claim 1, which is obtained by thermal denaturation at a temperature in the range of .degree. 6. The wound dressing according to claim 1, wherein the mucopolysaccharide is an acidic mucopolysaccharide. 7. The wound dressing according to claim 6, wherein the mucopolysaccharide is chondroitin sulfate, heparan sulfate, dermatan sulfate, hyaluronic acid, or heparin. 8. The wound dressing according to claim 7, wherein the mucopolysaccharide is chondroitin-6-sulfate. 9. The wound dressing material according to claim 1, wherein the collagen film is an oriented fiber. 10 Collagen film thickness is 5 to 500 μm
A wound dressing according to claim 1. 11. The wound dressing material according to claim 1, wherein the collagen film is porous.