Veterinary antibacterial peptide sustained-release gel as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of veterinary drug preparations, and particularly relates to veterinary antibacterial peptide sustained-release gel as well as a preparation method and application thereof. The veterinary antibacterial peptide sustained-release gel is prepared from the following materials in percentage by mass: 0.00005%-0.5% of antibacterial peptide; 0.25%-2% of a gel matrix; 2%-8% of an additive; the total percentage is 100%; the antibacterial peptide is antibacterial peptide Z (WK) 2, and the amino acid sequence of the antibacterial peptide is shown as SEQ ID NO.1; the gel matrix is prepared from any one or more of carboxymethyl cellulose, sodium carboxymethyl cellulose, hydroxyethyl cellulose, hydroxy propyl cellulose, hydroxypropyl methyl cellulose and carbomer; the additive comprises any one or more of propylene glycol, glycerol, sorbitol and polyethylene glycol. The veterinary antibacterial peptide sustained-release gel preparation provided by the invention consists of antibacterial peptide, a gel matrix and an additive, has an obvious antibacterial effect, and can inhibit proliferation of bacteria such as methicillin-resistant staphylococcus aureus and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of veterinary drug preparations, and specifically relates to an antimicrobial peptide sustained-release gel for animals, a preparation method thereof and an application thereof. Background Art

[0002] Bacterial infection is one of the major challenges faced by animal husbandry. It not only affects animal health and production performance, but also poses a threat to food safety and public health. However, the irrational use of antibiotics in animal husbandry has exacerbated the problem of bacterial resistance. The global use of antibiotics in livestock is three times that of humans, which has led to increased bacterial resistance, bringing adverse effects to human society, such as increased biosafety threats, increased environmental pollution, and constraints on economic development. In order to meet this challenge, the animal husbandry industry is gradually reducing the use of antibiotics and seeking alternative strategies. The European Union has banned the addition of growth promoters to animal feed since 2006, and my country has also launched a reduction in the use of veterinary antimicrobial drugs. Therefore, the development of new green, safe and efficient alternatives to veterinary antibiotics is of great practical significance.

[0003] In recent years, antimicrobial peptides can directly inhibit or kill viruses, fungi and bacteria in animals, and are biological agents that have been studied more recently in terms of anti-inflammatory mechanisms. Antimicrobial peptides have a non-specific membrane rupture mechanism and a broad-spectrum antimicrobial activity. They have great potential to become a weapon against drug-resistant bacteria and are also considered to be promising alternatives to antibiotics. Although antimicrobial peptides have excellent antibacterial effects and show good antibacterial activity against multidrug-resistant bacteria, most antimicrobial peptides have limited activity and are unstable in the environment. Therefore, it is necessary to use antimicrobial peptides to develop new veterinary antibiotic alternatives. Summary of the invention

[0004] In order to solve the problem of limited activity and instability of antimicrobial peptides in the environment in the prior art, the present invention provides a veterinary antimicrobial peptide sustained-release gel, a preparation method and an application thereof. To achieve the above object, the present invention adopts the following technical scheme.

[0005] The present invention provides a veterinary antimicrobial peptide sustained-release gel, which is made of the following materials in percentage by mass: Antimicrobial peptide 0.00005%~0.5%.

[0006] Gel matrix 0.25%~2%.

[0007] Additives 2%~8%.

[0008] Make up to 100% with distilled water.

[0009] The antimicrobial peptide is antimicrobial peptide Z(WK)2, and its amino acid sequence is shown in SEQ ID NO.1: WKWKCNSKSFCKWKW.

[0010] The gel matrix includes any one or more of carboxymethyl cellulose, sodium carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose and carbomer.

[0011] The additive includes any one or more of propylene glycol, glycerol, sorbitol and polyethylene glycol.

[0012] The veterinary antimicrobial peptide sustained-release gel provided by the present invention is made of antimicrobial peptide, gel matrix and additives. It has obvious antibacterial effect and can inhibit the proliferation of bacteria such as methicillin-resistant Staphylococcus aureus. At the same time, the veterinary antimicrobial peptide sustained-release gel provided by the present invention is highly active and stable in the environment, which is conducive to the antimicrobial peptide to better exert its antimicrobial effect. The hydrogel as a gel matrix can encapsulate the antimicrobial peptide, which can not only protect the antimicrobial peptide from the destruction of proteases in the environment, but also play a role of sustained release and prolong the in vitro action time; in addition, additives such as propylene glycol can have a moisturizing effect to prevent it from losing water when applied on the skin surface for a long time. At the same time, it was found during the experiment that propylene glycol as an additive can also assist the antimicrobial peptide in enhancing the antibacterial effect and play a combined antibacterial role. In summary, the antimicrobial peptide gel composite preparation has a better clinical application effect than a single antimicrobial peptide solution, solving the problem of limited and unstable activity of antimicrobial peptides in the environment in the prior art.

[0013] Preferably, it is made of the following materials in percentage by mass: The antimicrobial peptide Z(WK)2 is 0.1%~0.5%.

[0014] The hydroxypropyl methylcellulose is 0.5% to 2%.

[0015] The propylene glycol comprises 6% to 8%.

[0016] The distilled water makes up to 100%.

[0017] Preferably, it is made of the following materials in percentage by mass: The antimicrobial peptide Z(WK)2 0.5%.

[0018] The hydroxypropyl methylcellulose is 2%.

[0019] The propylene glycol comprises 8%.

[0020] The distilled water makes up to 100%.

[0021] The antimicrobial peptide Z(WK)2 with a mass percentage of 0.5% is the best therapeutic concentration screened by the mouse skin anti-infection test; the hydroxypropyl methylcellulose with a mass percentage of 2% can provide good skin adhesion when administered on the skin surface without affecting the antimicrobial effect of the antimicrobial peptide, and has a 3-day sustained-release effect, reducing the frequency of clinical administration; 8% propylene glycol can not only provide a good gel moisturizing effect, but also the antibacterial test shows that it can significantly enhance the antibacterial effect of the antimicrobial peptide. In summary, the above materials and concentrations are selected for the final formulation preparation.

[0022] The present invention also provides a method for preparing the veterinary antimicrobial peptide sustained-release gel, comprising the following steps: Weigh the antimicrobial peptide, gel matrix and additive according to the formula amount, add distilled water to make up to 100%, mix and fully swell, and obtain the veterinary antimicrobial peptide sustained-release gel. The preparation method of the veterinary antimicrobial peptide sustained-release gel prepared by the present invention has a simple process, good antimicrobial activity, good safety, a 3-day sustained-release effect, and good adhesion when applied to the skin, which can promote transdermal absorption of the drug and achieve a better drug administration effect.

[0023] The present invention also provides application of the veterinary antimicrobial peptide sustained-release gel in the preparation of antimicrobial drugs.

[0024] Preferably, the antibacterial drug uses the veterinary antibacterial peptide sustained-release gel as an active ingredient.

[0025] Preferably, the antibacterial drug is used against Gram-positive bacteria and Gram-negative bacteria.

[0026] Preferably, the Gram-positive bacteria include any one or more of Staphylococcus aureus, Staphylococcus haemolyticus, Streptococcus and Bacillus cereus.

[0027] Preferably, the Gram-negative bacteria include any one or more of Escherichia coli, Salmonella, Klebsiella pneumoniae and Proteus.

[0028] The present invention also provides the use of the veterinary antimicrobial peptide sustained-release gel in the preparation of a medicine for treating at least one of bacterial skin diseases, systemic septicemic infections and gastrointestinal infections in animal husbandry.

[0029] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention provides a veterinary antimicrobial peptide sustained-release gel. The veterinary antimicrobial peptide sustained-release gel provided by the present invention is composed of an antimicrobial peptide, a gel matrix and an additive. It has a significant antibacterial effect and can inhibit the proliferation of bacteria such as methicillin-resistant Staphylococcus aureus. At the same time, the veterinary antimicrobial peptide sustained-release gel provided by the present invention is highly active and stable in the environment, which is conducive to the antimicrobial peptide to better exert its antimicrobial effect. The hydrogel as a gel matrix can encapsulate the antimicrobial peptide, which can not only protect the antimicrobial peptide from damage by proteases in the environment, but also play a role of sustained release and prolong the in vitro action time; in addition, additives such as propylene glycol can have a moisturizing effect to prevent it from losing water when applied on the skin surface for a long time. At the same time, it was found during the experiment that propylene glycol as an additive can also assist the antimicrobial peptide in enhancing the antibacterial effect and play a combined antibacterial role. In summary, the antimicrobial peptide gel composite preparation has a better clinical application effect than a single antimicrobial peptide solution, solving the problem of limited and unstable activity of antimicrobial peptides in the environment in the prior art.

[0030] 2. The preparation method of the veterinary antimicrobial peptide sustained-release gel prepared by the present invention has a simple process, good antibacterial activity, good safety, a 3-day sustained-release effect, and good adhesion when applied to the skin, which can promote transdermal absorption of the drug and achieve a better drug delivery effect.

[0031] 3. The present invention mainly uses hydrogel preparations to overcome the problems of instability, high toxicity and short efficacy of antimicrobial peptides, and makes them an effective substitute for antibiotics in animal husbandry. The present invention screens out an optimal matrix from 6 gel matrices, which does not affect its antibacterial properties and has high safety. It has a sustained release effect within 3 days, and its clinical application effect is better than that of antimicrobial peptide aqueous solution and erythromycin ointment. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The results of in vitro hemolysis test of the gel matrix of the present invention are shown in Figure 1. HPMC: hydroxypropyl methylcellulose; HPC: hydroxypropyl cellulose.

[0033] Figure 2 The results are the in vitro release test results of the antimicrobial peptide gel preparation of the present invention.

[0034] Figure 3 This is a diagram showing the wound healing after skin bacterial treatment in the present invention; wherein, Figure 3 A in the figure is the blank control group; Figure 3 B in the figure is the model group; Figure 3 C in the figure is the antimicrobial peptide aqueous solution group; Figure 3 D in the figure is the antimicrobial peptide gel group; Figure 3 E in the figure is the positive drug control group.

[0035] Figure 4is a statistical diagram of bacterial load in skin tissue in the present invention; wherein, Figure 4 A in the figure is the blank control group; Figure 4 B in the figure is the model group; Figure 4 C in the figure is the antimicrobial peptide aqueous solution group; Figure 4 D in the figure is the antimicrobial peptide gel group; Figure 4 E in the figure is the positive drug control group. DETAILED DESCRIPTION

[0036] The present invention is described in detail below in conjunction with the accompanying drawings and specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the following examples are conventional means well known to those skilled in the art, and the materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial sources.

[0037] The antimicrobial peptide used in the embodiments of the present invention is antimicrobial peptide Z(WK)2, and its amino acid sequence is shown in SEQ ID NO.1: WKWKCNSKSFCKWKW.

[0038] The antimicrobial peptide Z(WK)2 is synthesized by GenScript Chemical, and the content of the synthesized antimicrobial peptide is >95%.

[0039] The gel base used in the following examples includes any one or more of carboxymethyl cellulose, sodium carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose and carbomer.

[0040] Among them, carboxymethyl cellulose is abbreviated as CMC in English, which was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; sodium carboxymethyl cellulose is abbreviated as CMC-Na in English, which was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; hydroxyethyl cellulose is abbreviated as HEC in English, which was purchased from Shanghai McLean Biochemical Technology Co., Ltd.; hydroxypropyl cellulose is abbreviated as HPC in English, which was purchased from Shanghai McLean Biochemical Technology Co., Ltd.; hydroxypropyl methyl cellulose is abbreviated as HPMC in English, which was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; and carbomer is called Carbomer in English, which was purchased from Shanghai McLean Biochemical Technology Co., Ltd.

[0041] Example 1: Screening of gel matrix (1) Take 0.05 g of carboxymethyl cellulose, sodium carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose and carbomer respectively, mix them with 10 mg of antimicrobial peptide Z(WK)2, and add 10 mL of distilled water to mix thoroughly to prepare an antimicrobial peptide gel solution. At the same time, prepare an antimicrobial peptide aqueous solution without gel matrix as a control.

[0042] The preparation method of the antimicrobial peptide aqueous solution without gel matrix is ​​as follows: 10 mg of antimicrobial peptide Z(WK)2 is weighed, and 10 mL of distilled water is added and mixed thoroughly to prepare the antimicrobial peptide aqueous solution without gel matrix.

[0043] (2) After the methicillin-resistant Staphylococcus aureus ATCC 33591 was activated for 3 generations in MHB medium, it was continuously cultured at 37°C and 200 r / min for 12 hours. After 12 hours, it was diluted 100 times with PBS solution, 20 μL of the diluted bacterial solution was taken on the MHA plate and evenly coated with a sterile cotton swab, and then a hole was punched with a 6 mm diameter puncher. 100 μL of antimicrobial peptide aqueous solution or antimicrobial peptide gel solution was added to the hole, cultured overnight, and the size of the inhibition zone was measured. The results are shown in Table 1.

[0044] Among them, the classification name of methicillin-resistant Staphylococcus aureus ATCC 33591 is MRSA, which was purchased from the China Veterinary Microbiological Culture Collection Center.

[0045] MHA medium and MHB medium were purchased from Beijing Aoboxing Biotechnology Co., Ltd., and the specific configuration method was the same as the instruction manual.

[0046] Overnight culture refers to culture time ≥ 12h.

[0047] Table 1 Size of inhibition zone of antimicrobial peptide gel As can be seen from Table 1, hydroxypropyl cellulose and hydroxypropyl methyl cellulose are more suitable as gel matrices for preparing veterinary antimicrobial peptide sustained-release gels, and do not affect the antibacterial activity of the antimicrobial peptide Z(WK)2.

[0048] Example 2: Hemolytic properties of gel matrix 5 mL of fresh defibrinated sheep blood was drawn up, centrifuged at room temperature at 1000 × g for 10 min, the supernatant was discarded, the lower layer of cell pellet was collected, and washed three times with PBS solution. PBS solution was added to resuspend the cell pellet to prepare a 2% v / v red blood cell suspension.

[0049] The prepared red blood cell suspension was added to a 96-well cell culture plate at a density of 100 μL / well, and then 100 μL of gel matrix was added to each well. PBS solution was set as a negative control and 0.1% v / v Triton X-100 was set as a positive control. The mass concentrations of hydroxypropyl cellulose and hydroxypropyl methylcellulose were set to 0.25% w / v, 0.5% w / v, 0.75% w / v and 1% w / v, and 3 replicates were set for each mass concentration. After mixing, incubate in a 37°C incubator for 1 hour and then centrifuge at 3000×g for 10 minutes. Pipette 100 μL of supernatant into a new 96-well plate and measure the absorbance at OD=576nm. Finally, the hemolysis rate of the gel matrix was calculated according to the cell hemolysis rate calculation formula. The results are shown in Figure 1 shown.

[0050] The cell hemolysis rate calculation formula is as follows: Hemolysis rate = (OD 576 - Negative control OD 576 ) / (positive control OD 576 - Negative control OD 576 )×100%; In the above formula, the unit of hemolysis rate is %.

[0051] Defibrinated sheep blood was purchased from Beijing Solebow Technology Co., Ltd.

[0052] PBS solution was purchased from Beijing Solebow Technology Co., Ltd., with a pH of 7.4.

[0053] The gel matrix is ​​obtained by fully mixing hydroxypropyl cellulose and hydroxypropyl methyl cellulose with PBS solution respectively.

[0054] Depend on Figure 1 The results show that at the same mass percentage concentration, hydroxypropyl methylcellulose has a lower biological hemolysis rate. Therefore, hydroxypropyl methylcellulose was selected as the gel matrix.

[0055] Example 3: In vitro time release curve of antimicrobial peptides from gel matrix Weigh 0.2 g of hydroxypropyl methylcellulose and 10 mg of antimicrobial peptide Z(WK)2, and fully dissolve them in 10 mL of PBS solution to prepare an antimicrobial peptide gel solution. The preparation method is the same as that in Example 1.

[0056] The antimicrobial peptide gel solution was placed in a dialysis bag and subjected to an in vitro release test under physiological conditions of 37°C, pH=7.4 PBS solution. At 1 hour, 2 hours, 3 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 24 hours, 36 hours, 48 ​​hours and 72 hours, 1 mL of liquid was aspirated from the outside of the dialysis bag and 1 mL of new PBS solution was added. The antimicrobial peptide concentration of each sample was determined by the BCA kit. The release curve results are shown in Figure 2. Figure 2 As shown,

[0057] Among them, dialysis bag: MwCO: 8000D~14000D.

[0058] The BCA kit was purchased from Bio-Tech Biotech Co., Ltd., and the detection method was the same as the instruction manual.

[0059] Depend on Figure 2 The results showed that the solution with hydroxypropyl methylcellulose as the gel matrix could release antimicrobial peptides over a period of 3 days and prolong the duration of drug action.

[0060] Example 4: Screening of additives Hydroxypropyl methylcellulose was used as the gel matrix, antimicrobial peptide Z(WK)2 was added, and propylene glycol was added at 0%, 2%, 4%, 6% and 8% v / v, and mixed thoroughly in PBS solution to prepare antimicrobial peptide gel solutions containing different propylene glycol concentrations. The in vitro antibacterial effects of antimicrobial peptides at different propylene glycol concentrations were investigated by the minimum inhibitory concentration test. The results are shown in Table 2.

[0061] The specific operation method is as follows: add 100 μL of MRSA bacterial solution to each well of a 96-well plate at a concentration of 1×10 6 CFU / mL, and then 100 μL of antimicrobial peptide gel solution containing different concentrations of antimicrobial peptides and different concentrations of propylene glycol were added respectively, wherein the w / v concentration of hydroxypropyl methylcellulose was 0.5%, the final concentration of antimicrobial peptides was 0.5-1024 μg / mL, and the v / v final concentration of propylene glycol was 0%, 2%, 4%, 6% and 8%.

[0062] Among them, the English abbreviation of the minimum inhibitory concentration test is MIC, and the unit is μg / mL.

[0063] The results show that the addition of propylene glycol can significantly improve the in vitro antibacterial effect of antimicrobial peptides. The effect of propylene glycol with a final v / v concentration of 8% is the most obvious, and the MIC can be reduced to 1 / 8 of the previous one. Therefore, propylene glycol with a final v / v concentration of 8% is selected as an additive for the antimicrobial peptide gel preparation.

[0064] Table 2 Minimum inhibitory concentration of antimicrobial peptide gel preparations Note: MIC is the minimum inhibitory concentration, unit: μg / mL.

[0065] Example 5: Mouse skin anti-infection test of antimicrobial peptide gel preparation Female BALB / c mice aged 6 to 8 weeks were selected and randomly divided into 5 groups: blank control group, model group, antimicrobial peptide aqueous solution group, antimicrobial peptide gel group, and positive drug control group. The positive drug control group used commercially available erythromycin ointment.

[0066] Before modeling, 2.5 mg / mouse of Shutai was injected intraperitoneally for anesthesia. After anesthesia, the hair on the back was shaved with a shaver, and a 10 mm circular wound was cut on the back with scissors. 9 CFU / mL of methicillin-resistant Staphylococcus aureus ATCC 33591 was applied to the circular wound. The drug was administered at the wound 3 days after infection, and the drug was administered once every 2 days for 10 consecutive days. The antimicrobial peptide aqueous solution group, antimicrobial peptide gel group and positive drug control group were given 100 μL of the corresponding drug on the circular wound, while the blank control group and model group were not given the drug. Photos were taken every 2 days to record the changes in the size of the circular wound. The mice were euthanized on the 10th day, and the wound tissue was taken for bacterial load determination. The difference in the therapeutic effect of antimicrobial peptide aqueous solution and antimicrobial peptide gel was compared by the wound healing condition and the amount of bacterial load.

[0067] Among them, the preparation method and concentration of erythromycin are the same as those in the patent instructions.

[0068] Preparation method of antimicrobial peptide aqueous solution group: weigh 50 mg of antimicrobial peptide Z(WK)2, add 10 mL of distilled water and mix thoroughly to prepare the antimicrobial peptide aqueous solution.

[0069] Preparation method of antimicrobial peptide gel solution: weigh 0.2 g of hydroxypropyl methylcellulose and 50 mg of antimicrobial peptide Z(WK)2, add 10 mL of distilled water and mix thoroughly to prepare the antimicrobial peptide gel solution.

[0070] Wound recovery and bacterial load results are shown in Figure 3 and Figure 4 .

[0071] After euthanasia, the dorsal skin wound tissues of the mice were cut and the bacterial load was detected.

[0072] The bacterial load detection method is as follows: Weigh about 1g of tissue and add 1mL PBS solution for homogenization. Centrifuge the homogenate at 500r / min for 5min and keep the supernatant. Dilute the supernatant 10 times in PBS solution, select 50μL of bacterial solution of each dilution and evenly spread on MHA plate. Incubate the MHA plate inverted at 37℃ for 24h and count the colonies.

[0073] The homogenization conditions were 600 Hz and 10 min.

[0074] The bacterial load was calculated as follows: log 10 (CFU / g) = log 10 (Number of colony counts / coating volume / dilution factor / tissue weight).

[0075] Depend on Figure 3 The results showed that the wound recovery in the antimicrobial peptide gel group was significantly better than that in the antimicrobial peptide aqueous solution group. The wound began to shrink significantly on the 6th day of treatment and was basically fully recovered on the 10th day of treatment.

[0076] Depend on Figure 4 The results showed that the skin bacterial load in the antimicrobial peptide gel group was significantly lower than that in the antimicrobial peptide aqueous solution group and the positive drug control group, indicating that the antimicrobial peptide gel group had a better bactericidal effect.

[0077] The above experimental results show that the antimicrobial peptide gel group has a better wound recovery effect than the antimicrobial peptide aqueous solution group. After 10 days of treatment, the wound recovery rate of the antimicrobial peptide gel group is better than that of the positive drug control group. The results of the bacterial load in skin tissue also show that the bactericidal effect of the antimicrobial peptide gel group is significantly better than that of the antimicrobial peptide aqueous solution group and the positive drug control group. After 10 days of treatment, the bacterial load in the antimicrobial peptide gel group decreased significantly.

[0078] From the above experimental results, it can be seen that the antimicrobial peptide gel solution has better clinical application effect than the antimicrobial peptide aqueous solution, significantly reduces the bacterial load and promotes wound recovery.

[0079] Antimicrobial peptides are often used in clinical practice for in vitro antibacterial treatment, such as skin infections and vaginal infections, due to their structural characteristics. However, complex environmental changes during infection, such as low pH and various proteases, may still lead to degradation and loss of activity of antimicrobial peptides, and they often exert rapid antibacterial effects through membrane destruction mechanisms. Therefore, the antimicrobial effectiveness of antimicrobial peptides is relatively short.

[0080] The present invention prepares an antimicrobial peptide gel solution by adding a gel matrix and an additive, and compares its therapeutic effect on skin infection by administering it in vitro for 2 days / time. The results show that under the condition of low-frequency administration of 2 days / time, the hydrogel preparation can still play a good wound recovery effect, and it is basically completely recovered in 10 days, while the wound recovery effect and skin bacterial load of the antimicrobial peptide aqueous solution group are significantly worse than those of the gel group, which may be related to the short efficacy time of the antimicrobial peptide aqueous solution and the degradation of the drug by components such as proteases. Therefore, the technical solution of the present invention can more effectively solve the problems of instability and short action time of antimicrobial peptides in clinical application, and significantly improve its clinical application value.

[0081] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. In order to avoid redundancy, the present invention describes a preferred embodiment.

[0082] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they understand the basic inventive concepts, and all such changes and modifications fall within the scope of the present invention.

Claims

1. A veterinary antimicrobial peptide sustained-release gel, characterized in that: Made of the following materials by mass percentage: Antimicrobial peptides 0.00005%~0.5%; Gel matrix 0.25%~2%; Additives 2%~8%; Distilled water to make up 100%; The antimicrobial peptide is antimicrobial peptide Z(WK)2, and its amino acid sequence is shown in SEQ ID NO.1; The gel matrix includes any one or more of carboxymethyl cellulose, sodium carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose and carbomer; The additive includes any one or more of propylene glycol, glycerol, sorbitol and polyethylene glycol.

2. The veterinary antimicrobial peptide sustained-release gel according to claim 1, characterized in that: Made of the following materials by mass percentage: The antimicrobial peptide Z(WK)2 0.1%~0.5%; The hydroxypropyl methylcellulose 0.5% to 2%; The propylene glycol 6% to 8%; The distilled water makes up to 100%.

3. The veterinary antimicrobial peptide sustained-release gel according to claim 2, characterized in that: Made of the following materials by mass percentage: The antimicrobial peptide Z(WK)2 0.5%; Said hydroxypropyl methylcellulose 2%; Propylene glycol 8%; The distilled water makes up to 100%.

4. The method for preparing the veterinary antimicrobial peptide sustained-release gel according to claim 1, characterized in that: The steps include: The antimicrobial peptide, gel matrix and additives are weighed according to the formula amount, and distilled water is added to make up to 100%. After mixing, the veterinary antimicrobial peptide sustained-release gel is obtained.

5. Use of the veterinary antimicrobial peptide sustained-release gel according to claim 1 in the preparation of antimicrobial drugs.

6. The use according to claim 5, characterized in that: The antibacterial drug uses the veterinary antibacterial peptide sustained-release gel as an active ingredient.

7. The use according to claim 6, characterized in that: The antibacterial drug is used to fight against Gram-positive bacteria and Gram-negative bacteria.

8. The use according to claim 7, characterized in that: The Gram-positive bacteria include any one or more of Staphylococcus aureus, Staphylococcus haemolyticus, Streptococcus and Bacillus cereus.

9. The use according to claim 7, characterized in that: The Gram-negative bacteria include any one or more of Escherichia coli, Salmonella, Klebsiella pneumoniae and Proteus.

10. Use of the veterinary antimicrobial peptide sustained-release gel according to claim 1 in the preparation of a medicament for treating at least one of bacterial skin diseases, systemic septicemic infections and gastrointestinal infections in animal husbandry.

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