Multi-layer wrapped microsphere antibacterial gel and preparation method thereof

Abstract

The invention belongs to the technical field of external pharmaceutical compositions, and particularly relates to a multi-layer coated microsphere antibacterial gel and a preparation method thereof. The gel is composed of three core components: multi-layer coated microspheres, a composite antibacterial component and a carbomer matrix solution. The antibacterial component comprises thymol, oregano oil, anisaldehyde, corilagin, ellagic acid and nano-silver, and aims to realize a broad-spectrum and efficient antibacterial effect. The preparation method comprises the following steps: preparing multi-layer coated microspheres by utilizing a micro-fluidic chip technology, coating a composite antibacterial component in the multi-layer coated microspheres, then dispersing the microspheres in a carbomer solution, and further compounding to obtain the microsphere antibacterial gel. During daily storage, the microspheres in the antibacterial gel can realize long-acting maintenance of the antibacterial components; when the gel is smeared on the skin surface, the gel microspheres are broken and release the internally-packaged antibacterial components, so that the antibacterial effect is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of external-use pharmaceutical compositions, and particularly relates to a multi-layer wrapped microsphere antibacterial gel and a preparation method thereof. Background Art

[0002] Antibacterial gel is a topical gel preparation with antibacterial effect, mainly used to prevent and treat bacterial infections on the skin surface.

[0003] Traditional wound treatment methods mainly rely on simple covering with gauze and bandages, but these methods are relatively passive when treating wounds and lack the ability to actively promote healing. Frequent replacement of these materials is not only cumbersome, but may also cause secondary damage to the wound due to improper operation. Their main function is limited to initial protection of the wound, but they are limited in creating a moist environment conducive to wound healing and effectively preventing bacterial reproduction. In addition, the antibacterial components in traditional antibacterial gels are easily affected by the external environment. When stored for a long time, the efficacy of some active ingredients is prone to decline, which limits the actual application effect.

[0004] In view of the above shortcomings, the development of new wound dressings has become an urgent problem to be solved in the medical field. This is not only related to the advancement of medical technology, but also indicates huge market opportunities. As a material with high water content, hydrogel has attracted much attention due to its high similarity to human tissue. Hydrogels exhibit excellent biocompatibility and certain antibacterial properties, creating a more superior environment for wound repair and effectively overcoming the limitations of traditional materials. However, hydrogels that have not been fully optimized still have room for improvement in antibacterial efficacy, and the long-term effectiveness of antibacterial components still needs to be improved to meet more stringent requirements in clinical applications. Summary of the invention

[0005] The present invention provides a multi-layer encapsulated microsphere antibacterial gel and a preparation method, the gel not only exhibits excellent antibacterial performance, but also has a significant wound repair promoting effect. The multi-layer microsphere structure can effectively encapsulate the antibacterial components to prevent them from being affected by the external environment, prolong their activity maintenance time, and facilitate the long-term storage of the gel. When the gel is applied to the skin surface, the gel microspheres rupture and release the antibacterial components encapsulated inside, thereby achieving an antibacterial effect. The present invention brings a new solution to the medical field of antibacterial gel.

[0006] A multi-layer wrapped microsphere antibacterial gel, comprising:

[0007] Phase A: mixed antibacterial ingredients

[0008] Phase B: Multi-layer encapsulated microspheres

[0009] Phase C: Carbomer mixture

[0010] The mixed antibacterial ingredients include: thymol, oregano phenol, anisaldehyde, corilagin, ellagic acid and nano silver.

[0011] The materials involved in the multi-layer wrapped microspheres include: mixed antibacterial solution, sodium alginate + Ca-EDTA complex, tetradecane, and tetradecane + acetic acid complex.

[0012] The phase A is finally dispersed into microspheres and located in the innermost layer of the multi-layer wrapped microspheres.

[0013] The B-phase fluid is injected into the microfluidic chip, and the B-phase fluid forms multi-layer wrapped microspheres with diameters ranging from micrometers to millimeters under the microfluidic hydrodynamic mode.

[0014] The multi-layer wrapped microspheres are wrapped by the C phase.

[0015] Preferably, the mass ratio of the mixed antibacterial components is carvacrol: oregano carvacrol: cinnamaldehyde: citral: gallic acid: nanosilver = (0.1-0.3): (0.1-0.3): (1): (0.2-0.3): (0.15-0.25): (0.01-0.05)

[0016] Preferably, the mass ratio of the components in the carbomer mixture is EDTA disodium: chitosan: carbomer: propylene glycol: glycerol = (0.02-0.06): (1-3): (0.4-1): (3): (1-3)

[0017] The method for preparing the aforementioned multi-layer encapsulated microsphere antibacterial gel comprises the following steps:

[0018] a) Preparation of mixed antibacterial solution

[0019] The mixed antibacterial components are dissolved in water to prepare an antibacterial solution.

[0020] b) Preparation of multilayer encapsulated microspheres

[0021] The mixed antibacterial solution, sodium alginate + Ca-EDTA complex, tetradecane, and tetradecane + acetic acid complex were injected into the four inlets of the microfluidic chip, respectively, to form multilayer wrapped microspheres under the microfluidic hydrodynamic mode.

[0022] c) Preparation of Carbomer Mixture

[0023] Disodium EDTA, chitosan, carbomer, propylene glycol and glycerol are dissolved in water to prepare a carbomer mixture, and then microspheres are added to the carbomer mixture to obtain a microsphere antibacterial gel.

[0024] Preferably, in the preparation of a) the mixed antibacterial solution, the total concentration of the mixed antibacterial components is 2-8 wt %.

[0025] Preferably, in the preparation of b) multi-layer wrapped microspheres, the diameter of the microspheres is 5 μm-2 mm.

[0026] The use of the aforementioned multi-layer encapsulated microsphere antibacterial gel in preventing and treating bacterial infections on the skin surface.

[0027] The present invention generates multi-layer wrapped microspheres by microfluidic technology, and the internal core of the microspheres contains mixed antibacterial ingredients. The microspheres are dispersed in a carbomer solution to finally obtain an antibacterial gel. Compared with traditional antibacterial gels, the multi-layer microsphere structure of the present invention can effectively wrap the antibacterial ingredients, prevent them from being affected by the external environment, prolong their activity maintenance time, and facilitate long-term storage of the gel. When the gel is applied to the skin surface, the gel microspheres rupture and release the antibacterial ingredients encapsulated inside, thereby achieving an antibacterial effect.

[0028] Antibacterial ingredients in the present invention:

[0029] Thymol: As a natural organic compound, thymol can inhibit the growth and reproduction of many bacteria. It inhibits the production of toxic substances in bacteria by interfering with bacterial DNA synthesis and protein regulation, thereby exerting an antibacterial effect. In addition, thymol can also destroy the normal structure of bacterial cell walls and cell membranes, further enhancing its antibacterial ability.

[0030] Oregano phenol: Oregano phenol can inhibit bacteria by blocking their respiratory oxidation process, destroying their energy metabolism, and further achieving the effect of antibacterial. Due to its advantages such as being natural, non-toxic, residue-free, and non-resistant, oregano phenol has broad application prospects in food preservation, animal health, medicine and other fields.

[0031] Anisaldehyde: As a natural product, anisaldehyde can inhibit the growth of many bacteria such as Staphylococcus aureus, and shows good antifungal effects, such as a significant inhibitory effect on Aspergillus flavus. Anisaldehyde can destroy the cell walls and cell membranes of bacteria or fungi, interfering with their normal physiological functions. Anisaldehyde also has the advantages of being non-toxic, having no side effects, and leaving no residue.

[0032] Corilagin: As a polyphenolic tannic acid, corilagin can inhibit the growth of many bacteria, especially against common pathogens such as Staphylococcus aureus. Corilagin also has broad-spectrum antibacterial, antioxidant, anti-inflammatory, antiviral and other biological activities.

[0033] Ellagic acid: Ellagic acid is a plant polyphenol compound. Its antibacterial effect is mainly reflected in the inhibition of various bacteria, including pathogenic bacteria such as Staphylococcus epidermidis and Bacillus cereus. Ellagic acid also has good antioxidant properties, which can scavenge free radicals and protect cells from oxidative damage. In the field of cosmetics, ellagic acid is often used as a whitening and anti-freckle ingredient and antioxidant. Its antibacterial properties also enable it to inhibit the growth of bacteria on the skin surface and maintain skin health.

[0034] Nanosilver: Nanosilver is a new type of antibacterial material obtained by nano-sizing silver using cutting-edge nanotechnology. Its particle size is mostly around 25 nanometers, and it has strong antibacterial and bactericidal properties. The antibacterial principle of nanosilver is that it can penetrate the cell membrane of microorganisms, bind to the enzymes in the cells, inactivate the enzymes, and thus block the respiratory metabolic system of the microorganisms, leading to their death. In addition, nanosilver also has a broad-spectrum antibacterial property, which can effectively fight against a variety of bacteria, fungi, viruses and other microorganisms, and will not produce drug resistance.

[0035] Given that each antibacterial ingredient has different focal points, simply increasing the concentration of a single ingredient to enhance the antibacterial effect is often ineffective and may aggravate the irritation problem. Therefore, the present invention cleverly selects multiple antibacterial ingredients with synergistic effects, and through their mutual cooperation, a more excellent antibacterial effect is achieved while maintaining or reducing the overall usage.

[0036] Compared with the prior art, the present invention has the advantage that the mixed antibacterial components are encapsulated in phase-change hydrogel microspheres, and the antibacterial components are protected by microspheres to extend the action time. At the same time, after the microspheres are sprayed onto the surface of human skin, the human body temperature is higher than the phase-change temperature of the microspheres, thereby causing the antibacterial components inside the microspheres to be released quickly, and the antibacterial effect of the gel is further enhanced. In the present invention, thymol, oregano phenol, anisaldehyde, corilagin, ellagic acid, and nano-silver are compounded into gel as antibacterial components, which significantly alleviates the skin irritation that may be caused by a single component at a high concentration, and greatly extends the antibacterial time of the product. The prepared microsphere gel not only shows excellent antibacterial performance, but also has a mild characteristic of low irritation to wounds, providing a safer and more efficient antibacterial solution for antibacterial gel products.

[0037] Compared with the prior art, the present invention has the advantage of using microfluidic chip technology to prepare multi-layer encapsulated microspheres, encapsulating the composite antibacterial components therein, and then dispersing the microspheres in a carbomer solution to compound into a microsphere antibacterial gel. During daily storage, the microspheres in the antibacterial gel can achieve long-term maintenance of the antibacterial components; when the gel is applied to the skin surface, the gel microspheres rupture and release the antibacterial components encapsulated inside, thereby achieving an antibacterial effect. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 A multi-layer wrapped microsphere generating device of the present invention; Figure 2 A system for generating multi-layer encapsulated microspheres, and the generated multi-layer encapsulated microspheres. DETAILED DESCRIPTION

[0038] In order to better understand the present invention, the present invention is further described below in conjunction with specific serial numbers, wherein the terms used in the serial numbers are for describing specific embodiments and do not constitute limitations on the scope of protection of the present invention.

[0039] In the specific implementation manner, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used can be obtained from commercial channels unless otherwise specified.

[0040] The sources of some raw materials used in the present invention are as follows: Table 1:

[0041] Table 1 Raw materials and sources used in multi-layer encapsulated microsphere antibacterial gel

[0042] name Product Name / Model / Other Name Source (Manufacturer) Sodium alginate Sodium Alginate Qingdao Nanshan Biotechnology Co., Ltd. Ca-EDTA complex Ca-EDTA complex Shandong Jinrunzi Biotechnology Co., Ltd. Tetradecane n-Tetradecane Hubei Rishengchang New Material Technology Co., Ltd. Acetic acid glacial acetic acid Shijiazhuang Chensheng Environmental Protection Technology Co., Ltd. Thymol 5-Isopropyl-2-methylphenol Wuhan Lanabai Pharmaceutical Chemical Co., Ltd. Oregano Bis(chlorobenzyl)biguanide Hebei Hongtao Bioengineering Co., Ltd. Anisaldehyde β-phenylacrolein Hubei Jusheng Technology Co., Ltd. Korilagin Geranial Firmenich Fragrances (China) Co., Ltd. Ellagic acid 3,4,5-Trihydroxybenzoic acid Tianjin Jindong Tianzheng Fine Chemical Reagent Factory Nano Silver AgNPs (Silver Nanoparticles) Suzhou Nanotech Co., Ltd. Disodium EDTA Disodium EDTA Sigma-Aldrich (Shanghai) Trading Co., Ltd. Chitosan Chitosan Zhejiang Golden Shell Biochemical Co., Ltd. Carbomer Carbomer U20 Nouyo Chemical (Shanghai) Co., Ltd. Propylene glycol Methyl glycol Dow Chemical (China) Investment Co., Ltd. glycerin Glycerol Zhangzhou Pien Tze Huang Pharmaceutical Co., Ltd.

[0043] Preparation of antibacterial gel

[0044] a) Preparation of mixed antibacterial solution

[0045] The mixed antibacterial components are dissolved in water to prepare an antibacterial solution.

[0046] b) Preparation of multilayer encapsulated microspheres

[0047] The microsphere preparation process is achieved through a microfluidic system. The technical solution for preparing microspheres is further explained below through a specific implementation method.

[0048] In one embodiment, the present invention provides a multi-layer encapsulated microsphere generating device, the device as Figure 1 As shown, it includes a pressure pump 1 and a pressure controller 2 connected by a gas pipeline 3, a mixed antibacterial solution storage bottle 4, a mixed antibacterial solution 5, a sodium alginate + Ca-EDTA complex storage bottle 6, a sodium alginate + Ca-EDTA complex 7, a tetradecane storage bottle 8, tetradecane 9, a microfluidic chip 11, an inverted optical microscope 12, a computer control system 13, multi-layer wrapped microspheres 14, a tetradecane + acetic acid complex 15, and a collection pool 16 connected by a fluid pipeline 10.

[0049] The mixed antibacterial solution, sodium alginate + Ca-EDTA complex, tetradecane, and tetradecane + acetic acid complex were injected into the four inlets of the microfluidic chip respectively. Under the microfluidic hydrodynamic mode, the sodium alginate + Ca-EDTA complex wrapped the mixed antibacterial solution and was sheared into monodisperse droplets by tetradecane. Then, when the droplets entered the collection pool, alginate reacted with acetic acid, and the macromolecules were cross-linked and solidified, thereby forming multi-layer wrapped microspheres, encapsulating the mixed antibacterial solution in the innermost part.

[0050] Figure 2 The invention relates to a multi-layer encapsulated microsphere generating system and the generated multi-layer encapsulated microsphere, wherein the core of the microsphere is a mixed antibacterial component.

[0051] c) Preparation of Carbomer Mixture

[0052] Disodium EDTA, chitosan, carbomer, propylene glycol, and glycerol were dissolved in water to prepare a carbomer mixture. Then, microspheres were added to the carbomer mixture to obtain microsphere antibacterial gel. The specific ratios are shown in Table 2 (showing the ratios of 5 groups of antibacterial gels with different ingredients); at the same time, based on these 5 groups of ratios, ordinary antibacterial gels were prepared for subsequent antibacterial comparative experiments to verify the antibacterial properties of the multi-layer encapsulated microsphere antibacterial gel.

[0053] Table 2 Preparation ratio of multi-layer encapsulated microsphere antibacterial gel

[0054]

[0055] Note: In Table 2, except for the concentration of antibacterial solution, all other units are parts by mass.

[0056] Sample stability test:

[0057] 1. Heat resistance test: Set the constant temperature incubator to 30°C. Then, for each of the 10 samples prepared previously, take out three samples and put them into transparent glass bottles. Ensure that the sample volume of each bottle is 20 ml. After the sample is loaded and sealed, place the glass bottles in a constant temperature incubator. After three months of continuous testing, take out the samples and wait for them to return to room temperature. Then carefully observe and record the changes in the appearance of each sample.

[0058] 2. Cold resistance test: Adjust the constant temperature incubator to -10℃. For each of the 10 samples prepared previously, take out three samples and put them into transparent glass bottles, ensuring that the sample volume of each bottle is 20 ml. After sealing, place the glass bottle in the adjusted constant temperature incubator. After three months of low temperature testing, take out the samples and restore them to room temperature, then carefully observe and record the changes in the appearance of each sample.

[0059] 3. Normal temperature test: For the 10 samples prepared previously, take out three samples of each sample and put them into transparent glass bottles, and keep the sample volume of each bottle at 20 ml. After the samples are filled and sealed, place the samples at normal room temperature. After one month of storage, take out the samples and directly observe whether there are any changes in their appearance.

[0060] No precipitation, precipitate, cracking, water loss, or damage was observed in the heat resistance test, cold resistance test, and room temperature test, and the original appearance was maintained. At the same time, the internal microsphere rupture rate was less than 5%, and the antibacterial ingredients were well wrapped and protected.

[0061] Human skin patch test

[0062] The five groups of samples numbered 1 to 5 were tested according to the human skin patch test method specified in the "2022 Cosmetic Safety Technical Specifications". During the test, the skin reactions of the subjects must be carefully observed according to standard procedures at three specific time points - 30 minutes (after the indentation completely subsides), 24 hours and 48 hours, and the results of each observation must be recorded in detail. After rigorous observation and recording, it was confirmed that at the three evaluation nodes of 30 minutes, 24 hours and 48 hours, the skin reaction level of all subjects was level 0, indicating that the samples did not cause any adverse reactions in the test.

[0063] Antibacterial activity evaluation

[0064] The antibacterial activity of the 10 groups of samples obtained was determined by the improved filter paper method (similar to the traditional method), and the diameter of the inhibition zone was used as the main evaluation index to quantify the antibacterial effect.

[0065] The specific steps are:

[0066] Preparation of antibacterial tablets: accurately cut the antibacterial gel products corresponding to each serial number into circular thin slices with a diameter of 6 mm, and use them as antibacterial tablets for later use, ensuring that each tablet is of the same size.

[0067] Preparation of bacterial plates: First, select the strain to be tested and culture it overnight in a nutrient-rich medium to promote its growth. Second, dilute the cultured strain with phosphate buffered saline (PBS) to an appropriate concentration (10 6 cfu / mL) to ensure uniform distribution of the bacterial solution. Use the plate coating method to evenly coat the diluted bacterial solution on the surface of the nutrient agar plate to ensure uniform coverage without omissions. Finally, place the coated plate at room temperature to dry naturally for about 5 minutes to allow the bacterial solution to fully adsorb on the agar surface.

[0068] Antibacterial effect test: First, gently place the prepared antibacterial sheet on the stained agar plate to ensure that the antibacterial sheet fits tightly against the bacterial layer to avoid bubbles. Then, place the fitted plate in a constant temperature incubator and set a suitable temperature for incubation, usually for 18 hours, to observe the antibacterial effect. Finally, after the incubation, use a vernier caliper to accurately measure the outer diameter of the antibacterial circle (i.e., the antibacterial diameter, in millimeters) and record the data. To ensure the accuracy of the experimental results, each test group must be measured three times, and the average value must be calculated as the basis for evaluating the final antibacterial diameter.

[0069] The results are shown in Table 3.

[0070] Table 3 Antibacterial results

[0071]

[0072] As can be seen from Table 3, group 10 has the best antibacterial effect, but considering that too high a concentration may cause irritation and the concentration difference with group 9 is not obvious, the concentration of the antibacterial solution of the present invention is limited to 2-8%.

[0073] From the comparison of groups 1-10, it can be seen that when multi-layer wrapped microspheres are used to encapsulate antibacterial components, the storage time of the antibacterial components can be effectively extended. After the microspheres are broken, more effective antibacterial components are released, thereby achieving a better antibacterial effect. The above detailed description is a specific description of one of the feasible embodiments of the present invention. The embodiment is not intended to limit the scope of the present invention. Any equivalent implementation or change that does not deviate from the present invention should be included in the scope of the technical solution of the present invention.

Claims

1. A multi-layer encapsulated microsphere antibacterial gel, comprising: Phase A: mixed antibacterial ingredients Phase B: Multi-layer encapsulated microspheres Phase C: Carbomer mixture The mixed antibacterial ingredients include: thymol, oregano phenol, anisaldehyde, corilagin, ellagic acid, and nanosilver; The materials involved in the multi-layer wrapped microspheres include: mixed antibacterial solution, sodium alginate + Ca-EDTA complex, tetradecane, tetradecane + acetic acid complex; The phase A is finally dispersed into microspheres and located in the innermost layer of the multi-layer wrapped microspheres; The phase B fluid is injected into the microfluidic chip, and the phase B fluid forms multi-layer wrapped microspheres with a diameter of micrometer to millimeter level under the microfluidic hydrodynamic mode; The multi-layer wrapped microspheres are wrapped by phase C; The mass ratio of the mixed antibacterial components is carvacrol: oregano carvacrol: cinnamaldehyde: citral: gallic acid: nanosilver = (0.1-0.3): (0.1-0.3): (1): (0.2-0.3): (0.15-0.25): (0.01-0.05); The mass ratio of the components in the carbomer mixture is disodium EDTA:chitosan:carbomer:propylene glycol:glycerol=(0.02-0.06):(1-3):(0.4-1):(3):(1-3).

2. The method for preparing the multi-layer encapsulated microsphere antibacterial gel according to claim 1, characterized in that: The following steps are involved: a) Preparation of mixed antibacterial solution dissolving the mixed antibacterial components in water to prepare an antibacterial solution; b) Preparation of multilayer encapsulated microspheres The mixed antibacterial solution, sodium alginate + Ca-EDTA complex, tetradecane, and tetradecane + acetic acid complex were injected into the four inlets of the microfluidic chip, respectively, and multilayer wrapped microspheres were formed in the microfluidic hydrodynamic mode; c) Preparation of Carbomer Mixture Disodium EDTA, chitosan, carbomer, propylene glycol and glycerol are dissolved in water to prepare a carbomer mixture, and then microspheres are added to the carbomer mixture to obtain a microsphere antibacterial gel.

3. The method for preparing the multi-layer encapsulated microsphere antibacterial gel according to claim 2, characterized in that: In the preparation of the mixed antibacterial solution a), the total concentration of the mixed antibacterial components is 2-8 wt %.

4. The method for preparing the multi-layer encapsulated microsphere antibacterial gel according to claim 2, characterized in that: In the preparation of b) multi-layer wrapped microspheres, the diameter of the microspheres is 5 μm-2 mm.

5. Use of the multi-layer encapsulated microsphere antibacterial gel according to claim 1 in preventing and treating bacterial infections on the skin surface.

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