TWI798649B - Medical dressing - Google Patents

Abstract

A medical dressing includes modified cellulose with cation groups, in which the modified cellulose is formed by cationization of a cellulose powder having crystallinity between 0 and 0.5.

Description

medical dressing

The present disclosure relates to medical dressings, and in particular to medical dressings comprising cellulose.

Polymer compounds with positive charges can interfere with the growth of bacteria or cause the death of bacteria, so they can be used as medical antibacterial products, such as dressing materials, patches, sutures, etc. Materials of high molecular weight compounds include animal components and vegetable components such as chitosan or modified cellulose. However, chitosan requires a lot of chemical solvents to process and may cause allergic reactions, while the production of cellulose products is limited by its inefficient modification process. Therefore, how to improve the modification efficiency of cellulose is an important development project for medical dressings.

The present disclosure provides a medical dressing, which includes modified cellulose with cationic groups, so as to have good antibacterial effect.

According to some embodiments of the present disclosure, the medical dressing includes modified cellulose with cationic groups, wherein the modified cellulose is formed by cationizing cellulose powder with a crystallinity between 0 and 0.5.

In some embodiments, the degree of substitution of the cationic groups of the modified cellulose ranges from 0.25 to 0.6.

In some embodiments, the bacteriostatic value of the medical dressing is between 85% and 100%.

In some embodiments, the cellulose powder with a crystallinity ranging from 0 to 0.5 is obtained by wet grinding cellulose raw materials in a neutral aqueous solution.

In some embodiments, the wet milling includes milling the cellulose feedstock with a planetary ball mill and zirconia beads, wherein the zirconia beads have a diameter ranging from 0.2 cm to 1.0 cm.

In some embodiments, the cellulose powder is cotton powder.

In some embodiments, the cationization of the cellulose powder comprises dissolving the cellulose powder in an alkaline solution, adding a quaternary ammonium salt to the alkaline solution, heating the alkaline solution, and performing a drying process on the alkaline solution to form Modified cellulose.

In some embodiments, the alkaline solution is a sodium hydroxide solution with a concentration between 5 wt% and 10 wt%.

In some embodiments, the concentration of the quaternary ammonium salt in the alkaline solution is between 6.0 wt% and 6.5 wt%.

In some embodiments, the quaternary ammonium salt includes 3-chloro-2-hydroxypropyltrimethylammonium chloride.

According to the above embodiments of the present disclosure, since the medical dressing includes modified cellulose with cationic groups, the medical dressing can have a good antibacterial effect. On the other hand, since the cellulose powder used to form the modified cellulose has low crystallinity, the modifying efficiency of the cellulose powder can be increased, and the use of modifying agents can be reduced to reduce the modification cost.

The following disclosure presents a number of different embodiments or examples in order to achieve the different features of the mentioned subject matter. Specific examples of numerical values, operations, materials, etc. are described below to simplify the present disclosure. Of course, these are examples only, not limiting.

Herein, the structure of a polymer or a group is sometimes represented by a skeleton formula. This notation can omit carbon atoms, hydrogen atoms, and carbon-hydrogen bonds. Where an atom or an atomic group is clearly drawn in a structural formula, the drawn one shall prevail.

The present disclosure provides a medical dressing, which includes modified cellulose with cationic groups, so as to have good antibacterial effect. Since the modified cellulose is obtained by modifying the cellulose powder with low crystallinity, the modification efficiency of the cellulose powder can be increased and the modification cost can be reduced.

The medical dressing of the present disclosure includes modified cellulose, wherein the modified cellulose has cationic groups, thereby providing the medical dressing with good antibacterial effect. Modified cellulose is formed by subjecting cellulose powder to a modification process. More specifically, the modified cellulose is formed by cationizing cellulose powder with a crystallinity between 0 and 0.5 by a modifying agent. Since the low crystallinity of the cellulose powder can promote the chemical reaction between the cellulose powder and the modifying agent, thereby increasing the modifying efficiency of the cellulose powder and improving the antibacterial effect of the medical dressing.

式(1) 其中R是陽離子基團。在一些實施方式中，改質纖維素的陽離子基團可包括帶正電荷的四級胺基團。舉例而言，在以式(1)表示的改質纖維素的單體中，R可以是具有陽離子的2-羥丙基-N,N,N-三甲基銨基團，其單體可具有如以下式(2)所示的結構，

式(2)。 In some embodiments, the cellulose molecules in the cellulose powder are cationized, so that the cationic groups can replace the hydroxyl functional groups of the cellulose molecules, thereby forming a modified cellulose with cationic groups. Specifically, the monomer of the modified cellulose may have the structure shown in the following formula (1),

Formula (1) wherein R is a cationic group. In some embodiments, the cationic groups of the modified cellulose may include positively charged quaternary amine groups. For example, in the monomer of the modified cellulose represented by formula (1), R may be a cationic 2-hydroxypropyl-N,N,N-trimethylammonium group, and the monomer may be Has the structure shown in the following formula (2),

Formula (2).

In some embodiments, the modified cellulose may have a suitable degree of substitution of cationic groups such that the modified cellulose has a suitable amount of positive charge. Therefore, the modified cellulose with positive charges can provide good antibacterial effect for medical dressings. In some embodiments, the degree of substitution of the cationic groups of the modified cellulose may range from 0.25 to 0.6. Specifically, if the degree of substitution of the cationic group is less than 0.25, it may not be able to provide effective positive charges, thereby reducing the antibacterial effect of the medical dressing; and if the degree of substitution of the cationic group is greater than 0.6, it may increase the modification cost. At the same time, the antibacterial effect of medical dressings cannot be significantly increased, resulting in waste of resources. In some embodiments, since the medical dressing includes modified cellulose with a suitable degree of substitution, the bacteriostatic value of the medical dressing can be between 85% and 100%, and the bacteriostatic effect of the medical dressing can be extended to one or more strains.

In some embodiments, forming the modified cellulose may include subjecting the cellulose raw material to a wet milling process to form a cellulose powder. In this way, the crystallinity of the formed cellulose powder can be reduced, thereby increasing the modification efficiency of the cellulose powder in the subsequent modification process. Specifically, a wet grinding process can be performed on cellulose raw materials in a neutral aqueous solution to form cellulose powder, wherein water can be used as a lubricant or reduce the process temperature, thereby reducing the addition of organic solvents or acid-base solutions, And can avoid the residue of chemical solvents.

In some embodiments, the wet milling process may include grinding the cellulose raw material using a planetary ball mill and zirconia beads, and the weight ratio of the zirconia beads to the cellulose raw material may be between 90 and 100. Cellulose feedstock can be ground using zirconia beads of suitable diameter to form a cellulose powder with low crystallinity. For example, the diameter of the zirconia beads can be between 0.2 cm and 1.0 cm, preferably between 0.5 cm and 1.0 cm.

In some embodiments, the cellulose raw material can be selected from ingredients with high cellulose content, so that the formed cellulose powder has low content of impurities, thereby reducing the steps of repurification of the cellulose powder. For example, cotton can be selected as the cellulose raw material, and the cellulose powder obtained through the wet grinding process is cotton powder. Since cotton powder has low content of lignin, ash and other impurities, the medical dressing made of it can have low risk of allergies, which can increase the applicability of the medical dressing.

The medical dressing of the present disclosure includes modified cellulose, and the modified cellulose is formed by cationizing cellulose powder with a crystallinity between 0 and 0.5. Specifically, cationizing the cellulose powder may include the following steps. First, cellulose powder is dissolved in an alkaline solution. Then, the quaternary ammonium salt is added to the alkaline solution, and the alkaline solution is heated. Finally, the alkaline solution is dried to form modified cellulose.

Specifically, the ground cellulose powder can be dissolved in an alkaline solution as a catalytic environment to promote the subsequent cationic substitution reaction. Since the cellulose powder is ground to have low crystallinity, the cellulose powder can be uniformly distributed in a low-concentration alkaline solution. Therefore, an alkaline solution with an alkaline substance concentration of less than 10wt% can be selected to carry out the above cationic substitution reaction, so as to reduce the use and residue of chemical solvents. Preferably, the alkaline solution may be, for example, a sodium hydroxide solution with a concentration between 5 wt % and 10 wt %.

Next, a quaternary ammonium salt including cationic groups is added to the above basic solution and the basic solution is heated so that the cationic groups of the quaternary ammonium salt replace the hydroxyl functional groups of the cellulose powder. In some embodiments, the quaternary ammonium salt may include 3-chloro-2-hydroxypropyltrimethylammonium chloride, which can increase the modification efficiency of cationization through its activity. In this way, cationic substitution reactions can be achieved using low concentrations of quaternary ammonium salts. For example, the concentration of the quaternary ammonium salt in the alkaline solution may be between 6.0 wt% and 6.5 wt%. In some embodiments, the alkaline solution can be heated to 70° C. to 80° C. for 3 to 4 hours, and then the alkaline solution is dried to form the modified cellulose with cationic groups.

According to the above-mentioned embodiments of the present disclosure, the modified cellulose having cationic groups is formed by cationizing the cellulose powder, so that the medical dressing including the modified cellulose has a good antibacterial effect. Due to the low crystallinity of the cellulose powder, it can promote the cationization between the cellulose powder and the modifier, thereby increasing the degree of substitution of the modified cellulose, improving the modification efficiency, reducing the use of modifiers and chemical solvents, and reducing the Modification cost.

In the following description, various measurements and evaluations will be performed on the modified cellulose of the present disclosure and the medical dressing including the modified cellulose. The features of the present disclosure will be described in more detail below with reference to Experimental Example 1 and Experimental Example 2. Although the following examples are described, materials used, their amounts and ratios, processing details, processing flow, and the like can be appropriately changed without departing from the scope of the present disclosure. Therefore, the present disclosure should not be limitedly interpreted by the embodiments described below. <Experimental example 1: Evaluation of crystallinity of cellulose powder>

各實施例與比較例的纖維素原料的濕式研磨參數以及結晶度的測量結果如表一所示。 In this experimental example, wet grinding was performed on the cellulose raw material of each example, and the crystallinity evaluation was performed on the cellulose powder formed in each example and the unground cellulose raw material of the comparative example. Specifically, the crystallinity is obtained by measuring the diffraction intensity of cellulose powder or cellulose raw material by an X-ray diffraction analyzer, and using the following method (3) to calculate, wherein I _22.6 and I _18.5 are respectively cellulose powder or Diffraction intensities of crystalline and amorphous phases of cellulose raw materials in X-ray diffraction.

Table 1 shows the wet grinding parameters and crystallinity measurement results of the cellulose raw materials of each embodiment and comparative example.

Table I Cellulose raw material (g) Zirconia bead diameter (cm) Grinding speed (rpm) Grinding time (min) Crystallinity Example 1 2 0.5 20 10 0.42 Example 2 2 0.5 20 20 0.31 Example 3 2 0.5 20 30 0.015 Example 4 2 0.5 20 40 -0.05 Comparative example 1 2 unground 0.7 Comparative example 2 2 unground 0.7 Note 1: The weight of zirconia beads is 200g

It can be seen from Table 1 that the crystallinity of the unground cellulose raw material in the comparative example is greater than 0.5. In contrast, the crystallinity of the cellulose powder in each example is between 0 and 0.5 (although the crystallinity of Example 4 is -0.05, considering the measurement error of the instrument, the crystallinity can be regarded as 0). Therefore, after the cellulose raw material of each embodiment undergoes physical wet grinding, the cellulose powder can have a suitable crystallinity. ＜Experimental example 2: Substitution degree of modified cellulose and antibacterial evaluation of medical dressings＞

In this experimental example, a modification process was performed on the cellulose powder of each example and the cellulose raw material of the comparative example to evaluate the degree of substitution of the formed modified cellulose, and the same process was performed on each modified cellulose To evaluate the antibacterial effect of the formed medical dressing. Specifically, the degree of substitution of the modified cellulose is measured by an elemental analyzer to measure the content of nitrogen, and the degree of substitution of cationic groups is calculated using the following method (4), wherein N% is the content of nitrogen in the modified cellulose percentage.

各實施例和比較例的改質製程參數、取代度以及醫療敷材抑菌值的測量結果如表二所示。 On the other hand, the bacterial strains of the control group and the experimental group (such as Staphylococcus aureus, Streptococcus pneumoniae, etc.) were cultivated under the same conditions, and the medical dressings of each embodiment or comparative example were placed in the experimental group. After 18 to 24 hours of cultivation, measure the amount of bacteria remaining in the control group and the experimental group, and use the following method (5) to calculate the bacteriostatic value of each embodiment and comparative example.

The modification process parameters, degree of substitution and measurement results of the antibacterial value of the medical dressings in each embodiment and comparative example are shown in Table 2.

Table II Crystallinity Quaternary ammonium salt concentration Degree of substitution Staphylococcus aureus inhibitory value pneumococcal inhibitory value Example 1 0.42 6.28% 0.28 85.45% 85.20% Example 2 0.31 6.28% 0.34 95.88% 90.11% Example 3 0.015 6.28% 0.44 99.91% 99.92% Example 4 -0.05 6.28% 0.52 99.92% 99.92% Comparative example 1 0.7 6.28% 0 <0 <0 Comparative example 2 0.7 21.14% 0.21 <0 <0

It can be seen from Table 2 that the cellulose raw material of the comparative example has a high degree of crystallinity, the degree of substitution of the modified cellulose formed by it is less than 0.25, and the antibacterial values of the medical dressings including the modified cellulose of the comparative example are all less than 0 . In contrast, the modified cellulose is formed by the cellulose powder with low crystallinity in each embodiment, and the degree of substitution is between 0.25 and 0.6, which shows that each embodiment has good modification efficiency. In addition, each example was cationized by a lower concentration of quaternary ammonium salt, and the degree of substitution of the modified cellulose formed was greater than that of Comparative Example 2, which was cationized by a higher concentration of quaternary ammonium salt, so Various embodiments have lower modification costs. On the other hand, the medical dressing including the modified cellulose of each embodiment has a bacteriostatic value between 85% and 100% against Staphylococcus aureus and Streptococcus pneumoniae. That is to say, the medical dressings of each embodiment have good antibacterial effect.

Through the verification of the above experimental examples, the medical dressing of the present disclosure can include modified cellulose with an appropriate degree of substitution, which has good antibacterial effects against various bacterial strains. Modified cellulose is formed from cellulose powder with low crystallinity, and the low crystallinity of cellulose powder can increase modification efficiency and reduce modification cost.

The foregoing outlines features of some embodiments so that those skilled in the art may better understand the aspects of this disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures to achieve the same purposes and/or achieve the same advantages as the embodiments described herein. Those skilled in the art should also understand that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they can make various changes, substitutions and alterations without departing from the spirit and scope of the present disclosure.

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Claims (8)

A medical dressing, comprising modified cellulose, the modified cellulose has 2-hydroxypropyl-N,N,N-trimethylammonium groups, wherein the modified cellulose is obtained by increasing the crystallinity The cationization of cellulose powder between 0 and 0.5, the degree of substitution of the 2-hydroxypropyl-N,N,N-trimethylammonium group of the modified cellulose is between 0.25 and 0.6 Between, and the cellulose powder is cotton powder. The medical dressing according to claim 1, wherein the antibacterial value of the medical dressing is between 85% and 100%. The medical dressing according to claim 1, wherein the cellulose powder with a crystallinity between 0 and 0.5 is obtained by wet grinding cellulose raw materials in a neutral aqueous solution. The medical dressing according to claim 3, wherein the wet grinding includes grinding the cellulose raw material with a planetary ball mill and zirconia beads, wherein the diameter of the zirconia beads is between 0.2 cm and 1.0 cm. The medical dressing according to claim 1, wherein the cationization of the cellulose powder includes: dissolving the cellulose powder in an alkaline solution; adding a quaternary ammonium salt to the alkaline solution; heating the said alkaline solution; and The alkaline solution is dried to form the modified cellulose. The medical dressing according to claim 5, wherein the alkaline solution is a sodium hydroxide solution with a concentration between 5wt% and 10wt%. The medical dressing according to claim 5, wherein the concentration of the quaternary ammonium salt in the alkaline solution is between 6.0wt% and 6.5wt%. The medical dressing according to claim 5, wherein the quaternary ammonium salt includes 3-chloro-2-hydroxypropyltrimethylammonium chloride.