Liquid bandage and method of making same

Abstract

This invention provides a liquid wound dressing and its preparation method, belonging to the field of wound dressing technology. The preparation method of the liquid wound dressing provided by this invention includes the following steps: dissolving glycerin in water, adding alginate to obtain an alginate dispersion; adding silicate to the alginate dispersion to form a gel; and after cooling, adding cellulose to obtain the liquid wound dressing. The wound dressing prepared by this invention forms a film quickly, has a smooth surface, good breathability, good waterproofness, is convenient to use, and will not cause harm to the human body.

Description

Technical Field

[0001] This invention relates to the field of wound dressing technology, and more particularly to a liquid wound dressing and its preparation method. Background Technology

[0002] For minor cuts on the skin, fabric or adhesive bandages are typically used. These bandages provide hemostasis, wound protection, and promote healing. Fabric bandages (gauze, non-woven fabric) are mainly used for larger wounds, while adhesive bandages consist of an absorbent dressing (such as cotton) and an adhesive portion (for securing the wound), providing protection. However, these bandages easily absorb dust and moisture after use, increasing the risk of secondary infection. Furthermore, due to limitations in materials and thickness, these bandages often have poor breathability.

[0003] Liquid bandages can solve the problems mentioned above in the use and storage of traditional solid bandages. Existing liquid bandages include a product from the United States (cellulose dissolved in multiple organic solvents), a product from Japan (nitrocellulose dissolved in multiple organic solvents), US patent US4291025 (agar dissolved in water and diethylene glycol), US patent US5103812A (using a polymer or polymerizable monomer containing siloxanes), patent CN201010233179.7 (using chitosan, methylcellulose and multiple organic solvents), CN201911023695.4 (nitrocellulose and multiple organic solvents), and CN201810915271.8 (nitrocellulose and multiple organic solvents). Most of these products use organic solvents or organic polymers or polymer monomers to form a polymer film on the wound surface through evaporation, thereby achieving a protective effect on small wounds. Such organic polymers and solvents are generally toxic and not conducive to wound healing. They also typically cause stinging to the wound and are not suitable for children. The CN105056285 dressing for deep wounds uses sodium alginate and calcium carbonate dissolved in water to form a gel layer on a non-woven fabric layer, which has a healing effect on severe wounds. However, the use of non-woven fabric results in poor water resistance of this dressing. Therefore, finding a waterproof and safe wound dressing is the technical problem that this invention aims to solve. Summary of the Invention

[0004] The purpose of this invention is to provide a liquid wound dressing and its preparation method. The prepared wound dressing forms a film quickly, has a smooth surface, good breathability, good waterproof performance, is convenient to use, and will not cause harm to the human body.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing a liquid wound dressing, the method comprising the following steps:

[0007] (1) Dissolve glycerol in water, add alginate to obtain an alginate dispersion;

[0008] (2) Add silicate to the alginate dispersion to form a gel;

[0009] (3) After cooling, add cellulose to obtain liquid bandage.

[0010] Preferably, the volume-to-mass ratio of water, glycerol, and alginate is 100ml:3-6ml:0.5-5g; and the alginate is calcium alginate or sodium alginate.

[0011] Preferably, the pH of the alginate dispersion is adjusted to 5-7 using a pH adjuster; the pH adjuster is one or more of sodium hydroxide, sodium dihydrogen phosphate, and disodium hydrogen phosphate.

[0012] Preferably, in step (2), the mass-to-volume ratio of silicate to water is 1-3 g: 100 ml; the silicate is lithium magnesium silicate, calcium silicate or sodium silicate; the conditions for forming the gel are: temperature 10-50°C, time 8-12 min, and rotation speed 1800-2200 rpm.

[0013] Preferably, the temperature after cooling is 20-25°C.

[0014] Preferably, the cellulose is carboxymethyl cellulose or hydroxypropyl methylcellulose. When the cellulose is carboxymethyl cellulose, the mass-to-volume ratio of the added carboxymethyl cellulose to water is 6-8 g:100 ml; when the cellulose is hydroxypropyl methylcellulose, the mass-to-volume ratio of the added hydroxypropyl methylcellulose to water is 12-16 g:100 ml; and the rotation speed when adding the cellulose is 1800-2200 rpm.

[0015] Preferably, one or more of a preservative, pigment and fragrance are added to the water in step (1).

[0016] The present invention also provides a liquid wound dressing obtained by the preparation method described above.

[0017] The wound dressing provided by this invention is based on alginate, silicate, and cellulose, exhibiting excellent biocompatibility. Alginate possesses outstanding hemostatic, antibacterial, and tissue-healing and regeneration-promoting properties. Silicate gel is an inorganic mineral gel with low chemical activity, insoluble in water, oil, and alcohol, and does not react with them. When placed under dry conditions, it does not oxidize, acidify, decompose, or degrade, thus facilitating the formation of a thin film on the skin surface.

[0018] The bandage of this invention does not use any organic solvents, is easy to use, and will not cause harm to the human body. Unlike aqueous solution-based bandages, the bandage of this invention forms a film quickly, has a smooth surface, good breathability, and good waterproof performance. Detailed Implementation

[0019] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0020] Example 1

[0021] Add 4 mL of glycerol to 100 mL of pure water while stirring at 2000 rpm, then add 0.5 g of calcium alginate to obtain a calcium alginate dispersion. Next, add 1 g of lithium magnesium silicate and stir at 40°C for 10 minutes to form a gel. Cool to room temperature (25°C), and then add 6 g of carboxymethyl cellulose while stirring at 2000 rpm to obtain a liquid wound dressing. The liquid wound dressing has a pH of 7. It forms a stable, elastic, and waterproof film on the skin surface within 5 minutes after application.

[0022] Comparative Example 1

[0023] Liquid wound dressings were prepared using different types and proportions of cellulose, different proportions of calcium alginate, and the addition of a preservative (benzalkonium chloride). The effects of each factor on the performance of the liquid wound dressing were investigated.

[0024] Liquid bandage samples were obtained according to the preparation method of Example 1 and the formulations in Table 1. Specifically, formulation 1 omits calcium alginate and glycerin in Example 1, and replaces "6g carboxymethyl cellulose" with "4g hydroxypropyl methylcellulose" in Example 1, while keeping other steps the same as in Example 1, thus producing liquid bandage of formulation 1. Formulation 2 omits calcium alginate and glycerin in Example 1, while keeping other steps the same as in Example 1, thus producing liquid bandage of formulation 2. This process is repeated to obtain liquid bandages of formulations 3 to 18. (The preservative benzalkonium chloride is dissolved in pure water, and then glycerin, calcium alginate, etc., are added.)

[0025] Then, the mold was placed on the surface of a plastic plate, and the liquid bandage was evenly applied into the 3cm*3cm*0.2mm mold. The surface was smoothed with a plate, the mold was removed, and the plastic plate was placed in a forced-air drying oven at 60℃ for 30 minutes to obtain a smooth film. The film-forming characteristics were observed, and the results are shown in Table 1. As can be seen from Table 1, (i) to form a complete and smooth protective film on the skin surface, the amount of hydroxypropyl methylcellulose needs to be higher than 12%, or the amount of carboxymethyl cellulose needs to be higher than 6%; (ii) the amount of glycerin greater than or equal to 4% can improve the smoothness of the film formed on the skin surface; (iii) the amount of benzalkonium chloride less than or equal to 1% does not affect the film-forming characteristics.

[0026] Table 1 Comparison of film-forming properties of different formulations

[0027]

[0028]

[0029] Comparative Example 2

[0030] Several formulations (formulations 7, 9, 11, 14, 17, and 18) with good film-forming performance were selected from Comparative Example 1. The air permeability and water resistance of the formed films were evaluated and compared on glass slides. Air permeability was tested according to ASTM E95 using a water vapor permeability meter (model: WB-61-F-1), and water resistance was measured using the seat drop method contact angle (Germany Dataphysics OCA20). The results are shown in Table 2. Table 2 shows that formulations 7, 9, 11, and 18, containing hydroxypropyl methylcellulose, have lower water resistance than formulations 14 and 17, which contain carboxymethyl cellulose. Meanwhile, formulations 14 and 17 have higher water vapor permeability than formulations 7, 9, 11, and 18, indicating that under mold-forming conditions, carboxymethyl cellulose is superior to hydroxypropyl methylcellulose. Furthermore, Table 2 shows that the addition of lithium magnesium silicate results in a higher contact angle, better water resistance, and better air permeability.

[0031] The wound dressings prepared with formulas 7, 9, 11, 14, 17, and 18 all exhibited higher breathability than those prepared with Kobayashi Wound Control from Japan. In particular, the wound dressing prepared with formula 14 had a water vapor permeability of 27.4 g / m³. 2 / h, higher than the 4.87g / m of Kobayashi Soharun in Japan. 2 / h. Therefore, the optimal formulation is formulation 14: 0.5% lithium magnesium silicate, 6% carboxymethyl cellulose, 0.5% calcium alginate, 4% glycerol,

[0032] Table 2 Comparison of breathability and waterproofness of liquid wound dressings prepared with different formulations after film formation.

[0033]

[0034] Comparative Example 3

[0035] This comparative study measured the contact angle of the liquid wound dressing as it naturally forms a film on a glass slide and skin surface. Each group was repeated three times, and the contact angle was compared with that of Kobayashi Wound Healing from Japan. The liquid wound dressing gel was selected from Formula 14 in Table 2. The gel prepared according to Formula 14 was applied to a glass slide or skin surface, and after film formation, the intact film was peeled off. Its water resistance was measured using the seated drop method (Dataphysics OCA20, Germany). The results are shown in Table 3.

[0036] Table 3. Comparison of contact angles after liquid bandages naturally form a film.

[0037]

[0038]

[0039] Combining the results in Tables 2 and 3, due to the presence of oils and other substances on the skin, and the fact that the film formed on the skin surface is not as smooth as that on the glass slide, the contact angle data of the glass slide and the skin surface differ significantly. However, overall, the liquid wound dressing of this invention does not use organic solvents, is non-toxic and harmless, and achieves better water resistance than the Kobayashi Wound Healing (based on organic solvents) from Japan.

[0040] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a liquid wound dressing, characterized in that, The preparation method includes the following steps: (1) Dissolve glycerol in water, add alginate to obtain alginate dispersion; the volume-to-mass ratio of water, glycerol and alginate is 100ml:3~6ml:0.5~5g; (2) Add silicate to the alginate dispersion to form a gel; the mass-to-volume ratio of silicate to water is 1~3g:100ml; the silicate is lithium magnesium silicate, calcium silicate, or sodium silicate; the gel formation temperature is 40~50℃. (3) After cooling, cellulose is added to obtain a liquid bandage; the cellulose is carboxymethyl cellulose or hydroxypropyl methylcellulose. When the cellulose is carboxymethyl cellulose, the mass-volume ratio of the added carboxymethyl cellulose to water is 6~8g:100ml; when the cellulose is hydroxypropyl methylcellulose, the mass-volume ratio of the added hydroxypropyl methylcellulose to water is 12~16g:100ml.

2. The preparation method according to claim 1, characterized in that, The alginate is calcium alginate or sodium alginate.

3. The preparation method according to claim 2, characterized in that, The pH of the alginate dispersion is adjusted to 5-7 using a pH adjuster; the pH adjuster is one or more of sodium hydroxide, sodium dihydrogen phosphate, and disodium hydrogen phosphate.

4. The preparation method according to claim 3, characterized in that, The gel formation time in step (2) is 8~12 min, and the rotation speed is 1800~2200 rpm.

5. The preparation method according to claim 1, characterized in that, The temperature after cooling is 20~25℃.

6. The preparation method according to claim 5, characterized in that, The rotation speed when adding the cellulose is 1800~2200 rpm.

7. The preparation method according to claim 6, characterized in that, One or more of the following are added to the water in step (1): preservative, pigment and fragrance.

8. A liquid bandage prepared according to any one of claims 1 to 7.

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