Compound antibacterial preparation containing avibactam sodium and preparation method thereof

Abstract

The invention relates to the field of pharmaceutical preparations, and discloses a compound antibacterial preparation containing avibactam sodium and a preparation method thereof.The preparation is of a multi-layer structure, an inner layer is triple crosslinking hydrogel, and avibactam sodium included by beta-cyclodextrin and gelatin-Arabic gum microspheroidized meropenem are entrapped by the triple crosslinking hydrogel; according to the LPS-recognition-peptide-containing pH-sensitive hydrogel hydrogel, the interface barrier layer and the LPS-recognition-peptide-containing pH-sensitive outer hydrogel are coated outside, the structure effectively protects drugs, realizes continuous synergistic release, can respond to acidic pH of an infected microenvironment to accelerate release, and targets gram-negative bacteria through the LPS recognition peptide, so that the local drug concentration and the synergistic antibacterial efficacy are remarkably improved, and the drug resistance risk is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of pharmaceutical preparations, in particular to a compound antibacterial preparation containing avibactam sodium and a preparation method thereof. Background Art

[0002] The continued rise of bacterial resistance has become a serious challenge to global public health, necessitating the development of novel and effective antimicrobial strategies. β-lactam antibiotics, such as the carbapenem meropenem, are widely used clinically to treat a variety of serious bacterial infections due to their broad-spectrum antimicrobial activity and potent bactericidal effects. However, bacterial production of β-lactamases is a major mechanism of resistance to these antibiotics. To overcome this problem, β-lactamase inhibitors have emerged. Among them, avibactam sodium, a novel non-β-lactam β-lactamase inhibitor, effectively inhibits several important β-lactamases, including class A, class C, and some class D enzymes. Combination therapy with β-lactam antibiotics can restore or enhance their activity against resistant strains. The combination of avibactam sodium and meropenem has shown promising clinical promise against multidrug-resistant Gram-negative bacteria.

[0003] Although the combination of avibactam sodium and meropenem has a significant synergistic antibacterial effect, under traditional administration methods, these two drugs still face many challenges in terms of their pharmacokinetic properties, tissue distribution, and maintenance of effective concentrations at the site of infection. For example, systemic distribution of drugs may lead to unnecessary side effects, and the concentration at the site of infection may not be sufficient to completely eliminate pathogens, especially when facing complex infection structures such as biofilms. In addition, the physical and chemical properties of the drugs themselves, such as water solubility and stability, may also affect their delivery efficiency and ultimate therapeutic effect. Some active ingredients may degrade before reaching the target site, thereby reducing the actual available drug dose.

[0004] In the existing technology, although there are some studies on drug delivery systems aimed at improving the solubility, stability or sustained release of drugs, there is still room for improvement in the combination of specific antibacterial drugs, especially in the precise regulation of the synergistic release of two or more drugs in the infected microenvironment and the realization of targeted delivery. Current drug formulations often find it difficult to simultaneously meet multiple requirements such as drug protection, sustained release, and intelligent response and active targeting to the microenvironment of the infected site (such as pH changes). Therefore, the development of an intelligent compound antibacterial preparation that can effectively encapsulate and protect avibactam sodium and meropenem, achieve synergistic and controllable release of the two at the infected site, and actively target pathogens has important practical significance and application value for improving treatment efficacy and reducing the risk of drug resistance. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a compound antibacterial preparation containing avibactam sodium and a preparation method thereof. The present invention aims to solve the technical problems in the existing technology of insufficient drug stability and difficulty in achieving synergistic controlled release and targeted delivery at the infection site when avibactam sodium and meropenem are used in combination.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a compound antibacterial preparation containing avibactam sodium, the preparation comprising: The inner layer hydrogel is composed of an interpenetrating network structure formed by chitosan and sodium alginate in a mass ratio of 3:2, wherein the molecular weight of the chitosan is 50-70kDa and the molecular weight of the sodium alginate is 80-120kDa; the inner layer hydrogel contains avibactam sodium-β-cyclodextrin inclusion complex and meropenem-gelatin-arabic gum microspheres, wherein the amount of avibactam sodium is 0.45-0.55g and the amount of meropenem is 0.9-1.1g, relative to the total polymer mass of the inner layer hydrogel.

[0007] The IPN structure formed by chitosan and sodium alginate is not a simple physical mixture; rather, they interpenetrate each other at the molecular level, forming a denser and more stable three-dimensional network. This structure endows the hydrogel with excellent mechanical strength and swelling stability, enabling effective drug encapsulation and mitigating premature drug release. Furthermore, the complementary properties of the two polymers (such as chitosan's cationicity, pH sensitivity, and bioadhesive properties, and sodium alginate's anionicity and ionic crosslinking properties) lay the foundation for subsequent controlled drug release and functional modification.

[0008] The inner hydrogel layer contains avibactam sodium-β-cyclodextrin inclusion complex and meropenem-gelatin-gum arabic microspheres. Avibactam sodium, a β-lactamase inhibitor, is used in combination with meropenem, a carbapenem antibiotic, to overcome bacterial resistance through β-lactamase production.

[0009] Avibactam sodium-β-cyclodextrin inclusion complex: The hydrophobic inner cavity and hydrophilic outer shell structure of β-cyclodextrin can enclose the avibactam sodium molecules inside it, which not only improves the stability of avibactam sodium and prevents its premature degradation in complex physiological environments, but also improves its solubility and bioavailability, and regulates its release rate.

[0010] Meropenem-gelatin-gum arabic microspheres: By encapsulating meropenem in gelatin-gum arabic microspheres prepared by a complex coacervation method, meropenem is effectively protected from damage by the external environment (such as pH and enzymes), achieving its stable presence and sustained release within the inner hydrogel layer. This microspheroidization strategy facilitates the sustained release of meropenem, maintaining effective blood concentrations for a longer period of time and coordinating the release of avibactam sodium.

[0011] The dosage of avibactam sodium (calculated as avibactam sodium) is 0.45-0.55 g, and the dosage of meropenem (calculated as meropenem) is 0.9-1.1 g. Relative to the total polymer mass of the inner layer hydrogel, this design takes into account the effective dosage ratio of the two drugs in combination, in order to achieve an ideal synergistic antibacterial effect.

[0012] An interfacial barrier layer is arranged on the outer surface of the inner hydrogel, and the interfacial barrier layer is composed of 0.9-1.1 parts of phosphatidylcholine, 0.18-0.22 parts of cholesterol and 0.018-0.022 parts of membrane transport protein in a mass ratio, forming a cell membrane-like structure.

[0013] This interface layer mimics the structure and properties of biological membranes. Its main components, phosphatidylcholine and cholesterol, are the primary components of the phospholipid bilayer of cell membranes. This layer acts as a physical barrier, further mitigating premature and rapid leakage of drugs from the inner layer and enabling more precise controlled release.

[0014] The cell membrane-like structure can significantly improve the biocompatibility of the entire preparation and reduce nonspecific interactions and immunogenicity with biological tissues.

[0015] The introduction of membrane transporters is a key innovation. While their specific types and functions are not specified here, their presence suggests that this interfacial layer may have the ability to regulate transmembrane transport. For example, specific membrane transporters may facilitate the adhesion and internalization of agents at specific cell or tissue interfaces, or counteract the effects of certain drug efflux pumps, thereby increasing the effective concentration of the drug at the target site.

[0016] An outer layer of hydrogel is provided on the outer surface of the interface barrier layer, wherein the outer layer of hydrogel is composed of a comb-like copolymer of polyacrylic acid and polyethylene glycol, wherein the mass ratio of the main chain to the side chain is 1:3.5; the outer layer of hydrogel contains a bacterial lipopolysaccharide recognition peptide, and the amount thereof is 0.8-1.2% of the total mass of the comb-like copolymer in the outer layer of hydrogel.

[0017] Polyacrylic acid is a classic pH-sensitive polymer. The carboxyl groups on its chains undergo protonation or deprotonation under different pH conditions, leading to changes in the polymer chain conformation and altered hydrogel swelling behavior. The microenvironmental pH at the site of bacterial infection is typically lower than normal physiological pH (e.g., the acidic environment caused by inflammation). The pH-sensitive design of the outer hydrogel allows the formulation to respond to local pH changes upon reaching the infection site, such as structural changes (swelling or accelerated degradation), thereby promoting the release of the drug within.

[0018] The introduction of polyethylene glycol side chains not only modulates the copolymer's hydrophilicity and hydrophobicity, as well as the sensitivity and range of its pH response, but also provides a "stealth" effect, reducing recognition and clearance by the reticuloendothelial system and prolonging the formulation's circulation time in the body. The comb-like structure itself also facilitates the formation of a network with a specific pore size and responsiveness.

[0019] Lipopolysaccharide (LPS) is a major component of the outer membrane of Gram-negative bacteria. The incorporation of LPS-recognizing peptides into the outer hydrogel layer enables the formulation to actively target the site of Gram-negative bacterial infection. Upon reaching the infected area, the LPS-recognizing peptides specifically bind to LPS on the bacterial surface, enriching the formulation at the lesion. This active targeting mechanism not only increases the local concentration of the drug and reduces side effects on normal tissues, but also potentially enhances the antibacterial effect or triggers subsequent drug release through direct interaction with the bacteria.

[0020] Preferably, the inner layer hydrogel forms a triple cross-linked network structure through ionic cross-linking, enzymatic cross-linking and photosensitive cross-linking.

[0021] Hydrogels formed by a single cross-linking method often have limitations in precisely controlling mechanical properties, stability, or drug release behavior. A triple cross-linking strategy combining ionic cross-linking (such as sodium alginate with divalent cations), enzymatic cross-linking (using specific enzymes to catalyze the formation of covalent bonds between polymer chains, which offers advantages such as mild reaction conditions and high selectivity), and photosensitive cross-linking (using photoinitiators to trigger the cross-linking reaction under ultraviolet or visible light, which allows for precise spatial and temporal control) can significantly improve the mechanical strength, network stability, and anti-swelling ability of hydrogels. More importantly, the synergistic effect of different cross-linking methods allows for more precise control of the hydrogel's microstructure, pore size, and degradation rate, thereby enabling the optimized design of the encapsulated drug release behavior (such as release rate and programmed release) to adapt to the complex in vivo environment and therapeutic needs.

[0022] Preferably, the ionic crosslinking is achieved by calcium chloride, and its usage is 15-25% of the total mass of the inner hydrogel polymer; the enzymatic crosslinking is achieved by horseradish peroxidase, and its usage is 0.8-1.2% of the total mass of the inner hydrogel polymer; the photosensitive crosslinking is achieved by 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone, and its usage is 1.8-2.2% of the total mass of the inner hydrogel polymer.

[0023] Preferably, the surface of the meropenem-gelatin-gum arabic microspheres is modified with the chronic catalytic enzyme ZO-1.

[0024] Potential functions of ZO-1 modification: ZO-1 (Zonulaoccludens-1) is a protein associated with tight junctions. Its modification on the microsphere surface may have an innovative mechanism related to enhancing the interaction between the microspheres and specific biological interfaces.

[0025] For example, it may promote the retention of microspheres on the mucosal surface (such as in the intestinal or respiratory mucosa) by interacting with corresponding receptors or structures on the cell surface, or temporarily and locally regulate the tight junctions between cells under specific conditions, thereby increasing the permeability of drugs across the epithelial barrier, which is of great significance for oral or topical administration routes.

[0026] Preferably, the membrane transporter in the interface barrier layer is selected from P-glycoprotein and / or OATP transporter.

[0027] P-glycoprotein (P-gp) is a key drug efflux pump, and its overexpression is a major contributor to multidrug resistance and malabsorption. The introduction of P-gp into the outer layer may serve as a competitive substrate or regulator, depleting or inhibiting the efflux function of P-gp in target cells, thereby increasing intracellular drug concentrations. OATP (organic anion transporting polypeptide) transporters participate in the transmembrane transport of a variety of endogenous substances and drugs. Their presence in the interfacial layer may facilitate the transport of specific drug molecules (such as avibactam sodium or meropenem, or their metabolites) across biological membranes, enhancing drug absorption and targeting efficiency. This design embodies an innovative approach to optimizing pharmacokinetic behavior by actively regulating drug transport processes.

[0028] Preferably, a method for preparing a compound antibacterial preparation containing avibactam sodium comprises the following steps: S1. Preparation of avibactam sodium-β-cyclodextrin inclusion complex and meropenem-gelatin-gum arabic microspheres; S2. dispersing the avibactam sodium-β-cyclodextrin inclusion complex and the meropenem-gelatin-gum arabic microspheres in a mixed solution of chitosan and sodium alginate, forming a concentration gradient distribution of the drug particles by gradient centrifugation, and then performing ionic crosslinking, photosensitive crosslinking, and enzymatic crosslinking to form an inner layer hydrogel; S3, preparing an interfacial barrier layer on the surface of the inner hydrogel; S4, preparing an outer layer hydrogel comprising bacterial lipopolysaccharide recognition peptides on the surface of the interface barrier layer; S5. Cut, package and sterilize the formed double-layer hydrogel.

[0029] Preferably, when preparing meropenem-gelatin-gum arabic microspheres in step S1, under supercritical CO2-assisted conditions, the pressure is 9-11 MPa, the temperature is 34-36 ° C, the gelatin solution containing meropenem is added to the gum arabic solution, and the pH is adjusted to 3.8-4.2 to form a coagulation, which is then cross-linked with glutaraldehyde and surface modified with chronic catalytic enzyme ZO-1.

[0030] Preferably, in step S2, the ionic crosslinking uses a calcium chloride solution with a concentration of 0.8-1.2%; the photosensitive crosslinking is carried out at a wavelength of 360-370 nm and a power density of 8-12 mW / cm 2 The enzymatic cross-linking was performed at 37±1°C for 3.5-4.5 hours.

[0031] Preferably, the preparation of the interface barrier layer in step S3 comprises: dissolving phosphatidylcholine, cholesterol and membrane transport protein in an organic solvent and evaporating the solvent to form a thin film, then hydrating the solvent to form a liposome dispersion, spraying the dispersion on the surface of the inner hydrogel, and allowing the dispersion to stand at 4±1°C for 1.5-2.5 hours.

[0032] Preferably, the preparation of the outer layer hydrogel in step S4 includes: reacting polyacrylic acid with polyethylene glycol to prepare a comb-like copolymer; mixing the comb-like copolymer with bacterial lipopolysaccharide recognition peptide, N,N'-methylenebisacrylamide and a photoinitiator, and then coating the mixture on the surface of the interface barrier layer, performing photoinitiated crosslinking, and then degassing under a vacuum of 0.04-0.06 MPa for 25-35 minutes.

[0033] The present invention provides a compound antibacterial preparation containing avibactam sodium and a preparation method thereof. It has the following beneficial effects: 1. The present invention provides a compound antibacterial preparation containing avibactam sodium, which, through its carefully designed multi-layer drug delivery system, achieves programmed and synergistic release of the core components, avibactam sodium and meropenem. The unique interpenetrating network structure and triple cross-linking technology of the inner hydrogel combine the advantages of the biocompatible materials chitosan and sodium alginate, providing a stable carrier and a preliminary sustained-release barrier for the two drugs; the middle interface barrier layer further precisely controls the diffusion rate of drug molecules; and the outermost hydrogel responds to specific signals, ensuring that this compound antibacterial preparation can effectively protect the drugs under physiological conditions and achieve sustained and effective drug release, thereby extending the time window for the synergistic effect of avibactam sodium and meropenem, which is expected to enhance the overall antibacterial efficacy and reduce the potential frequency of dosing.

[0034] 2. The compound antibacterial preparation containing avibactam sodium of the present invention employs an innovative protection strategy for avibactam sodium and meropenem, two drugs with potentially unstable or easily degradable chemical properties. Avibactam sodium is prepared as an inclusion complex with β-cyclodextrin, and meropenem is encapsulated in gelatin-gum arabic composite microspheres, greatly enhancing the stability of these two key antibacterial drugs in complex biological environments. This encapsulation protection at the molecular and microstructural levels effectively prevents drug activity loss due to enzymatic hydrolysis, hydrolysis, or other adverse factors before reaching the infection target, ensuring that each component of the compound preparation can function at its maximum therapeutic potential. This is crucial for maintaining the inhibitory activity of avibactam sodium against β-lactamases and the bactericidal efficacy of meropenem.

[0035] 3. The compound antibacterial formulation containing avibactam sodium designed in this invention exhibits remarkable intelligent targeting and environmental responsiveness, thereby optimizing drug delivery efficiency and therapeutic precision. Bacterial lipopolysaccharide (LPS) recognition peptides are specifically integrated into the outermost hydrogel layer of the formulation, enabling the compound antibacterial formulation to actively recognize and bind to the characteristic LPS molecules at sites of Gram-negative bacterial infection, achieving preferential drug enrichment at the lesions. Even more ingenious, the matrix of the outer hydrogel is composed of a pH-sensitive polymer material that responds to the acidic microenvironment typically present in bacterially infected areas, triggering accelerated drug release and ensuring that avibactam sodium and meropenem are released at higher concentrations where and when they are most needed, thereby maximizing the local therapeutic effect and potentially minimizing side effects from systemic exposure. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a flow chart of the preparation method of a compound antibacterial preparation containing avibactam sodium. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] Please see the attached Figure 1 : Example 1: S1. Preparation of avibactam sodium-β-cyclodextrin inclusion complex and meropenem-gelatin-gum arabic microspheres Preparation of Avibactam Sodium-β-cyclodextrin Inclusion Complex: Dissolve 20g of β-cyclodextrin in 950mL of deionized water and stir at 60°C for 35 minutes until completely dissolved. After cooling to 25°C, add 10g of avibactam sodium (ensure that the final formulation contains 0.50g of avibactam sodium. This is the initial dosage; the inclusion rate and subsequent dosage must be precisely calculated and controlled) to a molar ratio of approximately 1:2.0.

[0039] The mixture was then ultrasonically treated (power 350 W, frequency 22.5 kHz) for 30 minutes and stirred at 25°C for 24 hours. The precipitate was collected by filtration and freeze-dried to obtain an avibactam sodium-β-cyclodextrin inclusion complex.

[0040] Preparation of meropenem-gelatin-gum arabic microspheres: Dissolve 5.0 g of gelatin in an appropriate amount of pure water, and dissolve 2.5 g of gum arabic in an appropriate amount of pure water.

[0041] Meropenem 1.0 g (to ensure that the active meropenem provided in the final formulation is 1.0 g) was added to the gelatin solution.

[0042] Under supercritical CO2-assisted conditions (pressure 10 MPa, temperature 35°C), the gelatin solution containing meropenem was slowly added to the gum arabic solution, and the pH was adjusted to 4.0 under stirring to form a co-agglomerate.

[0043] An appropriate amount of 0.5% (w / v) glutaraldehyde solution was added for cross-linking.

[0044] The microspheres were collected by centrifugation, washed, and surface modified with a buffer solution containing 10 mg of chronic catalytic enzyme ZO-1.

[0045] Finally, the modified meropenem-gelatin-gum arabic microspheres were obtained by freeze-drying.

[0046] S2. Preparation of inner hydrogel 3.0 g of chitosan (molecular weight 60 kDa) was dissolved in 100 mL of 1% (v / v) acetic acid solution, and 2.0 g of sodium alginate (molecular weight 100 kDa) was dissolved in 100 mL of deionized water.

[0047] The above-mentioned avibactam sodium-β-cyclodextrin inclusion complex (containing 0.50 g of avibactam sodium) and meropenem-gelatin-gum arabic microspheres (containing 1.0 g of meropenem) were dispersed in the sodium alginate solution and then mixed evenly with the chitosan solution under nitrogen protection.

[0048] To the mixture, 50 mg of horseradish peroxidase (HRP, equivalent to 1.0% of the total mass of the inner hydrogel polymer) and 100 mg of 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylacetophenone (photoinitiator, equivalent to 2.0% of the total mass of the inner hydrogel polymer) were added.

[0049] The above mixture is processed by gradient centrifugation technology to form the expected concentration gradient distribution of drug particles.

[0050] The mixture was then transferred to a mold and ionically crosslinked by immersing it in a sufficiently large volume of 1.0% (w / v) calcium chloride aqueous solution until the inner hydrogel absorbed 1.0 g of calcium chloride (equivalent to 20% of the total mass of the inner hydrogel polymer).

[0051] After taking out, the samples were exposed to 365 nm ultraviolet light (power density 10 mW / cm 2 ) for 10 min for photosensitive crosslinking.

[0052] Finally, the enzymatic cross-linking was completed by standing at 37°C for 4.0 hours to form the inner layer hydrogel.

[0053] S3. Preparation of interface barrier layer Dissolve 1.0 g of phosphatidylcholine, 0.20 g of cholesterol, and 20 mg of a membrane transporter (e.g., 10 mg of P-glycoprotein and 10 mg of an OATP transporter) in an appropriate amount of chloroform and rotary evaporate to form a uniform film. Rehydrate the film with a pH 7.4 buffer and sonicate to form a liposomal dispersion.

[0054] The dispersion was evenly sprayed onto the surface of the inner hydrogel prepared in S2, and then allowed to stand at 4° C. for 2.0 hours to form an interface barrier layer.

[0055] S4. Preparation of outer hydrogel Prepare a polyacrylic acid-polyethylene glycol comb copolymer (main chain to side chain mass ratio of 1:3.5) in advance. Dissolve 5.0 g of this comb copolymer in an appropriate amount of buffer. Then, add 50 mg of bacterial lipopolysaccharide recognition peptide (equivalent to 1.0% of the total mass of the comb copolymer), 100 mg of N,N'-methylenebisacrylamide (MBAA), and 20 mg of photoinitiator, and mix thoroughly.

[0056] The above mixture is evenly coated on the surface of the interface barrier layer prepared in S3.

[0057] Photo-initiated cross-linking is performed under UV light (eg, 365 nm).

[0058] After cross-linking, the preparation was placed under 0.05 MPa vacuum conditions for 30 min to eliminate bubbles and form an outer layer of hydrogel.

[0059] S5. Final processing The formed double-layer hydrogel compound preparation is cut into suitable sizes and sterile packaged to obtain the product.

[0060] Example 2: S1. Preparation of avibactam sodium-β-cyclodextrin inclusion complex and meropenem-gelatin-gum arabic microspheres Preparation of Avibactam Sodium-β-cyclodextrin Inclusion Complex: 18 g of β-cyclodextrin and 9 g of avibactam sodium (ensuring that the amount of avibactam sodium provided in the final preparation is 0.45 g) were used to prepare the product according to the method of Example 1, with an ultrasonic power of 300 W, a frequency of 20 kHz, a time of 25 minutes, and a stirring time of 22 hours.

[0061] Preparation of meropenem-gelatin-gum arabic microspheres: The preparation was prepared by referring to the method of Example 1 using 4.5 g of gelatin, 2.0 g of gum arabic and 0.9 g of meropenem (ensuring that the amount of active meropenem provided in the final preparation is 0.9 g).

[0062] The supercritical CO2 conditions were a pressure of 9 MPa, a temperature of 34°C, a pH adjusted to 3.8, a 0.4% (w / v) glutaraldehyde solution, and an amount of ZO-1 of 8 mg.

[0063] S2. Preparation of inner hydrogel 2.8g chitosan (molecular weight 50kDa) and 1.87g sodium alginate (molecular weight 80kDa) were used. The added avibactam sodium-β-cyclodextrin inclusion complex contained 0.45g avibactam sodium, and the meropenem microspheres contained 0.9g meropenem.

[0064] 37 mg of HRP (equivalent to 0.8% of the total mass of the inner hydrogel polymer, 4.67 g) and 84 mg of photoinitiator (equivalent to 1.8% of the total mass of the inner hydrogel polymer, 4.67 g) were added.

[0065] Ionic crosslinking was performed by immersing in a 0.8% (w / v) calcium chloride solution until the absorbed calcium chloride reached 0.70 g (equivalent to 15% of the total mass of the inner hydrogel polymer).

[0066] Photosensitive crosslinking conditions: 360nm UV light, power density 8mW / cm 2 , irradiation for 8 minutes. Enzymatic cross-linking conditions: 36°C, 3.5 hours.

[0067] S3. Preparation of interface barrier layer Use 0.9 g phosphatidylcholine, 0.18 g cholesterol, and 18 mg membrane transporter (eg, 9 mg P-glycoprotein and 9 mg OATP transporter) Prepared according to the method of Example 1, incubation conditions: 3°C, 1.5 hours.

[0068] S4. Preparation of outer hydrogel 4.5 g of polyacrylic acid-polyethylene glycol comb copolymer (main chain to side chain mass ratio 1:3.5) was used, along with 36 mg of bacterial lipopolysaccharide recognition peptide (equivalent to 0.8% of the total mass of the comb copolymer), 90 mg of MBAA, and 18 mg of photoinitiator.

[0069] Prepared according to the method of Example 1, vacuum degassing conditions: 0.04 MPa, 25 minutes.

[0070] S5. Final processing Same as Example 1.

[0071] Example 3: S1. Preparation of avibactam sodium-β-cyclodextrin inclusion complex and meropenem-gelatin-gum arabic microspheres Preparation of Avibactam Sodium-β-cyclodextrin Inclusion Complex: 22 g of β-cyclodextrin and 11 g of avibactam sodium (ensuring that the amount of avibactam sodium provided in the final preparation is 0.55 g) were used to prepare the product according to the method of Example 1, with an ultrasonic power of 400 W, a frequency of 25 kHz, and a time of 35 minutes; and a stirring time of 26 hours.

[0072] Preparation of meropenem-gelatin-gum arabic microspheres: The preparation was prepared by referring to the method of Example 1 using 5.5 g of gelatin, 3.0 g of gum arabic and 1.1 g of meropenem (ensuring that the amount of active meropenem provided in the final preparation is 1.1 g).

[0073] The supercritical CO2 conditions were a pressure of 11 MPa, a temperature of 36°C, a pH adjusted to 4.2, a 0.6% (w / v) glutaraldehyde solution, and a ZO-1 dosage of 12 mg.

[0074] S2. Preparation of inner hydrogel 3.2g chitosan (molecular weight 70kDa) and 2.13g sodium alginate (molecular weight 120kDa) were used. The added avibactam sodium-β-cyclodextrin inclusion complex contained 0.55g avibactam sodium, and the meropenem microspheres contained 1.1g meropenem.

[0075] 64 mg of HRP (equivalent to 1.2% of the total mass of the inner hydrogel polymer, 5.33 g) and 117 mg of photoinitiator (equivalent to 2.2% of the total mass of the inner hydrogel polymer, 5.33 g) were added.

[0076] Ionic crosslinking was performed by immersing in a 1.2% (w / v) calcium chloride solution until the absorbed calcium chloride reached 1.33 g (equivalent to 25% of the total mass of the inner hydrogel polymer).

[0077] Photosensitive crosslinking conditions: 370nm UV light, power density 12mW / cm 2 , irradiation for 12 minutes.

[0078] Enzymatic cross-linking conditions: 38°C, 4.5 hours.

[0079] S3. Preparation of interface barrier layer Use 1.1 g of phosphatidylcholine, 0.22 g of cholesterol, and 22 mg of membrane transporters (e.g., 11 mg of P-glycoprotein and 11 mg of OATP transporters).

[0080] Prepared according to the method of Example 1, incubation conditions: 5°C, 2.5 hours.

[0081] S4. Preparation of outer hydrogel 5.5 g of polyacrylic acid-polyethylene glycol comb copolymer (main chain to side chain mass ratio 1:3.5) was used, along with 66 mg of bacterial lipopolysaccharide recognition peptide (equivalent to 1.2% of the total mass of the comb copolymer), 110 mg of MBAA, and 22 mg of photoinitiator.

[0082] Prepared according to the method of Example 1, vacuum degassing conditions: 0.06 MPa, 35 minutes.

[0083] S5. Final processing Same as Example 1.

[0084] Comparative Example 1: Compared with Example 1, the difference is: Step S3 is omitted, that is, the interface barrier layer is not prepared.

[0085] When preparing the outer layer hydrogel in step S4, no bacterial lipopolysaccharide recognition peptide is added. Therefore, the outer layer hydrogel prepared in step S4 is directly coated on the surface of the inner layer hydrogel prepared in step S2.

[0086] The rest are the same.

[0087] Comparative Example 2: Compared with Example 1, the difference is: In step S1, avibactam sodium is directly dissolved and used without preparing an avibactam sodium-β-cyclodextrin inclusion complex.

[0088] When preparing meropenem-gelatin-gum arabic microspheres in step S1, the step of surface modification using the slow catalytic enzyme ZO-1 was omitted.

[0089] When preparing the inner layer hydrogel in step S2, only ionic crosslinking is performed (i.e., only calcium chloride solution is used for crosslinking), and the enzymatic crosslinking (no horseradish peroxidase is added) and photosensitive crosslinking (no 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylacetophenone is added, and no ultraviolet light irradiation is performed) steps are omitted.

[0090] The rest are the same.

[0091] Comparative Example 3: Compared with Example 1, the difference is: When preparing the inner layer hydrogel in step S2 , the mass ratio of chitosan to sodium alginate is adjusted to 1:1 (for example, 2.5 g of chitosan and 2.5 g of sodium alginate are used).

[0092] When preparing meropenem-gelatin-gum arabic microspheres in step S1, the supercritical CO2 auxiliary condition is omitted and a conventional stirring co-coagulation method is used at room temperature and pressure.

[0093] When preparing the outer layer hydrogel in step S4, the mass ratio of the main chain to the side chain in the comb-like copolymer of polyacrylic acid and polyethylene glycol is adjusted to 1:1.

[0094] The rest are the same.

[0095] Test experiment: Test Example 1: In vitro drug release characteristics and pH responsiveness evaluation 1. Experimental purpose: The in vitro cumulative release behaviors of avibactam sodium and meropenem from the preparations of Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3 under conditions of simulated physiological pH were compared.

[0096] The responsive release characteristics of the preparation of Example 1 relative to the preparation of Comparative Example 3 under the pH conditions of a simulated bacterial infection microenvironment were evaluated.

[0097] 2. Experimental materials and instruments: Preparation samples: compound antibacterial preparations prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3.

[0098] Release medium: Phosphate buffered saline (PBS, pH 7.4) Phosphate buffered saline (PBS, pH 5.5) Instruments and equipment: Constant temperature shaking incubator (37°C) Dialysis bags (e.g., 8000-14000Da molecular weight cut-off, pre-treated) Precision analytical balance Volumetric flasks, pipettes and other glassware magnetic stirrer centrifuge High performance liquid chromatography (HPLC) equipped with a UV detector and an appropriate chromatographic column (e.g., C18 column) Syringe, 0.22μm microporous filter membrane 3. Experimental steps: Part A: In vitro drug release at physiological pH (pH 7.4) Sample Preparation: Accurately weigh a certain amount of the formulation samples of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 (ensure that the initial drug loadings of avibactam sodium and meropenem in each sample are known and comparable; for example, a formulation block containing approximately 5 mg of avibactam sodium and 10 mg of meropenem is used). Place the weighed samples into pretreated dialysis bags and securely tie the bags.

[0099] Release experiments: Place the dialysis bags containing each formulation sample in a covered container filled with 50 mL of pH 7.4 PBS. Ensure that the dialysis bags are completely immersed in the release medium. Place all containers in a 37°C constant-temperature shaking incubator with horizontal shaking at 100 rpm.

[0100] Sampling: At pre-determined time points (e.g., 0.5 h, 1 h, 2 h, 4 h, 6 h, 8 h, 12 h, 24 h, 36 h, 48 h), aspirate 1.0 mL of release medium from each container. Immediately after each sampling, add 1.0 mL of fresh, pre-warmed, pH 7.4 PBS to the corresponding container to maintain a constant release volume and sink conditions.

[0101] Sample Preparation and Analysis: The sample was filtered through a 0.22 μm microporous membrane. The concentrations of avibactam sodium and meropenem in the filtrate were determined using a validated HPLC method. The mobile phase, flow rate, column temperature, and detection wavelength were optimized based on the properties of avibactam sodium and meropenem. Drug concentrations were calculated using a standard curve.

[0102] Data processing: Based on the measured drug concentrations and sampling volumes, the cumulative release percentages of avibactam sodium and meropenem at each time point were calculated.

[0103] Part B: pH-responsive drug release Sample preparation: Accurately weigh the formulation samples of Example 1 and Comparative Example 3 (ensure that the initial drug loading is known and comparable, as in Part A). Place the samples into pre-treated dialysis bags and tie them tightly.

[0104] Initial Release (pH 7.4): Place the dialysis bags containing samples of the formulations of Example 1 and Comparative Example 3 in covered containers filled with 50 mL of pH 7.4 PBS. Place the containers in a 37°C shaking incubator with horizontal shaking at 100 rpm. Samples were collected at time points of 0.5 h, 1 h, and 2 h, following the same procedures as in Steps 3 and 4 of Section A.

[0105] pH conversion and subsequent release (pH 5.5): After the 2-hour sampling period, carefully remove the dialysis bag from the pH 7.4 PBS, quickly rinse the surface with a small amount of deionized water (to avoid drug loss), and then immediately transfer it to a new container filled with 50 mL of pH 5.5 PBS preheated to 37°C. The new container was then placed in a 37°C constant temperature shaking incubator with horizontal shaking at 100 rpm.

[0106] Sampling under acidic conditions: At specific time points after the pH shift (e.g., 2.5 h, 3 h, 4 h, 6 h, 8 h, 12 h, 24 h relative to the start of the experiment), sample the release medium at pH 5.5 using the same method as steps 3 and 4 in Part A.

[0107] Data processing: Based on the measured drug concentrations and sampling volumes, the cumulative release percentages of avibactam sodium and meropenem at each time point (including pH 7.4 and pH 5.5 stages) were calculated.

[0108] Experimental data: Table 1: In vitro cumulative release percentage of avibactam sodium from different formulations in pH 7.4 PBS (%)

[0109] Table 2: In vitro cumulative release percentage of meropenem from different formulations in pH 7.4 PBS (%)

[0110] Table 3: In vitro cumulative release percentage (%) of avibactam sodium in Example 1 and Comparative Example 3 under different pH conditions

[0111] Table 4: In vitro cumulative release percentage of meropenem under different pH conditions in Example 1 and Comparative Example 3 (%)

[0112] In vitro drug release test results (Tables 1 and 2) preliminarily demonstrate that the multilayered composite formulation constructed in Example 1 exhibited a more gradual and sustained release profile for both avibactam sodium and meropenem under simulated physiological pH conditions of 7.4, compared to Comparative Example 1, which lacked an interfacial barrier layer and an outer targeting peptide layer; Comparative Example 2, which lacked effective drug inclusion / entrapment and simplified the crosslinking of the inner hydrogel layer; and Comparative Example 3, which had a modified ratio of key polymer components. This is primarily attributed to the interpenetrating network structure of the inner hydrogel in Example 1, formed by chitosan and sodium alginate, combined with ionic, enzymatic, and photosensitive triple crosslinking, providing a stable and dense sustained-release matrix for the drugs. Furthermore, the pretreatment steps of avibactam sodium inclusion by β-cyclodextrin and meropenem entrapped in gelatin-gum arabic microspheres effectively delayed the initial rapid dissolution of the drugs. In addition, the interfacial barrier layer arranged on the outer surface of the inner hydrogel, with its dense cell membrane-like structure, further plays a barrier regulating role in the outward diffusion of drug molecules, and jointly promotes the sustained release of drugs.

[0113] The data in Tables 3 and 4 further reveal the differences in the release behavior of the Example 1 formulation under different pH conditions. When the pH of the release medium shifts from 7.4 (physiological conditions) to the acidic pH of 5.5 (simulating the bacterial infection microenvironment), the cumulative release rates of Aviba and Meropenem in Example 1 show a certain degree of acceleration. This pH-responsive release behavior is closely related to the design of the formulation's outermost hydrogel layer. This outer hydrogel is composed of a comb-like copolymer of polyacrylic acid and polyethylene glycol with a specific main chain to side chain ratio (1:3.5). The carboxyl groups on the polyacrylic acid segments undergo a change in protonation under acidic conditions, resulting in changes in the swelling behavior or degradation rate of the hydrogel network, thereby promoting the release of the drug within. In contrast, the pH responsiveness of Comparative Example 3 may not be as optimized as that of Example 1 due to the different main chain to side chain ratio of the outer hydrogel copolymer, resulting in a potential difference in the degree of accelerated drug release under acidic conditions.

[0114] In summary, the avibactam sodium-containing compound antibacterial formulation designed in Example 1, through its multilayer structure, drug pre-encapsulation / entrapment technology, triple-crosslinked network of the inner hydrogel layer, and pH-sensitive design of the outer hydrogel layer, achieves sustained, slow release of both antibacterial drugs at physiological pH, and exhibits an accelerated release trend under acidic pH conditions simulating infection sites. These properties help prolong the duration of drug action and potentially achieve timely and efficient drug release at the site of infection, demonstrating the innovative nature and potential advantages of this formulation in drug delivery system design.

[0115] Test Example 2: Evaluation of drug protection effect 1. Experimental Purpose: To evaluate the protective effect of the avibactam sodium-β-cyclodextrin inclusion complex technology and the meropenem-gelatin-gum arabic microsphere technology used in Example 1 on the active pharmaceutical ingredient in a simulated degradation environment, compared to Comparative Example 2 in which the drug was not effectively included / encapsulated.

[0116] 2. Experimental materials and instruments: Preparation samples: compound antibacterial preparations prepared in Example 1 and Comparative Example 2.

[0117] Degradation medium: phosphate buffered saline (PBS, pH 8.0, simulating a mild alkaline environment to accelerate the hydrolysis of β-lactam drugs).

[0118] Extraction solvent: acetonitrile (or other appropriate organic solvent selected according to the properties of the drug).

[0119] Instruments and equipment: Constant temperature shaking incubator (37°C) Precision analytical balance Volumetric flasks, pipettes, centrifuge tubes and other glass and plastic containers Tissue homogenizer or ultrasonic cell disruptor (for preparation disruption and drug extraction) High-speed refrigerated centrifuge High performance liquid chromatography (HPLC) equipped with a UV detector and an appropriate chromatographic column (e.g., C18 column) Syringe, 0.22μm microporous filter membrane 3. Experimental steps: Initial drug content determination (0h): Accurately weigh three fresh formulation samples of Example 1 and three fresh formulation samples of Comparative Example 2 (ensure that the theoretical initial drug loading of avibactam sodium and meropenem in each sample is known and comparable, for example, each sample contains a formulation block containing approximately 5 mg of avibactam sodium and 10 mg of meropenem).

[0120] Drug extraction was performed on each 0h sample: a. Place the sample in an appropriate amount of extraction solvent (e.g., 10 mL of acetonitrile / water mixture).

[0121] b. Use a tissue homogenizer or ultrasonic cell disruptor to fully disrupt the preparation to ensure that the drug is dissolved as completely as possible.

[0122] c. Centrifuge the extract at high speed (e.g., 10,000 rpm, 15 minutes) at 4°C to remove insoluble excipients.

[0123] d. Take the supernatant and filter it with a 0.22 μm microporous membrane.

[0124] Determine the concentrations of avibactam sodium and meropenem in the filtrate using a validated HPLC method. Calculate the actual initial drug content (mg) in each sample. The average of the three replicates is used as the drug content at time 0 for the formulation.

[0125] Degradation experiment: Accurately weigh multiple samples of the formulations of Example 1 and Comparative Example 2 (consistent with the weighing method and theoretical drug content of the 0h samples).

[0126] Each sample was placed in a sterile container with a lid containing 20 mL of pH 8.0 PBS.

[0127] All containers were placed in a 37°C constant temperature shaking incubator and shaken horizontally at a speed of 50 rpm.

[0128] Sampling and drug extraction (at different time points): At preset time points (e.g., 6 h, 12 h, 24 h, 48 h), the sample containers of Example 1 and Comparative Example 2 corresponding to the time points were taken out from the incubator (it is recommended to prepare three parallel samples for each formulation at each time point).

[0129] Immediately remove the entire sample of the formulation from the container.

[0130] Following steps ad to the drug extraction of the 0 h sample in step 1, perform drug extraction and HPLC analysis on the samples at each time point to determine the remaining intact avibactam sodium and meropenem content (mg).

[0131] Data processing: Based on the measured remaining drug content at each time point and the drug content at 0 h measured in step 1, calculate the residual percentage of avibactam sodium and meropenem at each time point.

[0132] Residual percentage (%) = (drug content measured at time point t / drug content measured at 0h) × 100% Experimental data: Table 5: Residual percentage (%) of avibactam sodium after incubation in pH 8.0 PBS at 37°C for different time periods in Example 1 and Comparative Example 2

[0133] Table 6: Residual percentage (%) of meropenem after incubation in pH 8.0 PBS at 37°C for different time periods in Example 1 and Comparative Example 2

[0134] The results of drug protection evaluation experiments (shown in Tables 5 and 6) clearly demonstrate that after incubation for varying periods of time in a simulated mildly alkaline degradation environment (PBS, pH 8.0, 37°C), both avibactam sodium and meropenem in the formulation of Example 1 exhibited significantly better stability than the formulation of Comparative Example 2. Specifically, as the incubation time increased, the residual percentages of the two active pharmaceutical ingredients in Example 1 remained consistently higher than those in Comparative Example 2. This directly demonstrates the effective protective effect of the specific drug pretreatment technology employed in Example 1, slowing its degradation rate in adverse environments.

[0135] The high stability of avibactam sodium in Example 1 is mainly due to its inclusion complex formed by pre-inclusion with β-cyclodextrin. The unique molecular structure of β-cyclodextrin, that is, the cavity with hydrophilic outside and hydrophobic inside, can embed avibactam sodium molecules therein to form a host-guest complex. This inclusion complex not only improves the solubility of the drug, but more importantly, it can effectively isolate the drug molecules from direct contact with the external adverse environment, as if providing it with a micro "protective shell", thereby significantly reducing its hydrolysis or other degradation pathways in a pH 8.0 medium. In contrast, the avibactam sodium in Comparative Example 2 was not subjected to such inclusion treatment and was directly exposed to the degradation medium, so it showed faster degradation.

[0136] Similarly, the excellent stability of meropenem in Example 1 is attributed to its successful encapsulation within gelatin-gum arabic microspheres. Prepared via a specific complex coacervation method and cross-linked with glutaraldehyde, the microspheres create a physical barrier for meropenem, effectively preventing its contact with external degrading factors and potentially further stabilizing the drug through microenvironmental regulation. This microspheroidization strategy not only protects the chemical structure of meropenem but also lays the foundation for its subsequent controlled release. Comparative Example 2 omits this sophisticated microsphere preparation process (or directly disperses the drug), making meropenem more susceptible to environmental degradation. Therefore, the application of these drug protection strategies is one of the key innovations of the present invention, ensuring drug activity during storage and application.

[0137] Test Example 3: Evaluation of in vitro bacterial lipopolysaccharide (LPS) binding ability 1. Experimental Purpose: To evaluate the binding ability of the formulation of Example 1 (the outer hydrogel contains LPS recognition peptide) and the formulation of Comparative Example 1 (the outer hydrogel does not contain LPS recognition peptide) to bacterial lipopolysaccharide (LPS) through in vitro experiments, so as to indirectly assess the potential of the formulation of Example 1 to target sites of Gram-negative bacterial infection.

[0138] 2. Experimental materials and instruments: Preparation samples: The compound antibacterial preparations prepared in Example 1 and Comparative Example 1 were prepared into fine particles or suspensions suitable for experiments.

[0139] Bacterial lipopolysaccharide (LPS): for example, LPS from Escherichia coli O111:B4.

[0140] Coating buffer: for example, carbonate buffer (pH 9.6).

[0141] Washing buffer: for example, phosphate buffered saline containing 0.05% Tween-20 (PBST, pH 7.4).

[0142] Blocking solution (optional, but recommended): for example, 1% bovine serum albumin (BSA) in PBS.

[0143] Lysis / elution buffer: For example, PBS containing 0.1% TritonX-100, or a solvent system that can effectively lyse the formulation and release the drug.

[0144] Instruments and equipment: 96-well ELISA plate (high adsorption capacity) Pipettes and tips Constant temperature incubator (37°C) Microplate reader (if indirect enzyme-linked reaction detection is used, but here HPLC is used to directly detect the amount of drug) centrifuge High performance liquid chromatography (HPLC) equipped with a UV detector and an appropriate chromatographic column (e.g., C18 column) Syringe, 0.22μm microporous filter membrane 3. Experimental steps: LPS-coated microplates: a. Dilute LPS to an appropriate concentration (e.g., 10 μg / mL) in coating buffer.

[0145] b. Add 100 μL of diluted LPS solution to each well of a 96-well microtiter plate. Set up blank control wells and add only coating buffer.

[0146] c. Incubate at 4°C overnight (or at 37°C for 2 hours).

[0147] d. Discard the liquid in the wells and wash the microplate three times with wash buffer, soaking for 1-2 minutes each time, and then pat dry.

[0148] Closure (optional): a. Add 200 μL of blocking solution to each LPS-coated well and blank control well.

[0149] b. Incubate at 37°C for 1-2 hours to block nonspecific binding sites.

[0150] c. Discard the liquid in the wells, wash the microplate three times with wash buffer, and pat dry.

[0151] Preparation sample incubation: a. The formulation samples of Example 1 and Comparative Example 1 were prepared into suspensions of a certain concentration using an appropriate amount of PBS (pH 7.4) (eg, such that each 100 μL suspension contained approximately the same amount of drug or formulation dry weight).

[0152] b. Add 100 μL of the suspension of the preparation of Example 1 and the suspension of the preparation of Comparative Example 1 to the LPS-coated wells, respectively. Set up at least three parallel wells for each sample.

[0153] c. Simultaneously, add the formulation suspension to some wells not coated with LPS (or to blank wells treated with coating buffer only, or to blocked blank wells if no blocking step was performed) as a control for nonspecific adsorption.

[0154] d. Incubate at 37°C for 1-2 hours with gentle shaking.

[0155] washing: a. After incubation, discard the liquid in the wells.

[0156] b. Carefully wash the microplate five times with wash buffer to completely remove unbound formulation particles. Pat dry thoroughly after each wash.

[0157] Drug elution and quantification of conjugated formulations: a. Add 100 μL of Lysis / Eluate Buffer to each washed well.

[0158] b. Incubate at room temperature for 30 minutes (or adjust the time based on elution efficiency) with appropriate shaking to allow the drug bound to the formulation to be fully released into the eluate.

[0159] c. Carefully transfer the eluate in each well to a new centrifuge tube.

[0160] d. If necessary, centrifuge the eluate and take the supernatant.

[0161] e. Filter the supernatant using a 0.22 μm microporous filter membrane.

[0162] f. Determine the concentration of avibactam sodium (or meropenem) in the filtrate using a validated HPLC method.

[0163] Data Processing: Calculate the amount of drug bound to the LPS-coated wells based on the measured drug concentration and eluate volume. The amount of drug measured in nonspecifically bound control wells (wells not coated with LPS but with formulation added) can be subtracted from the amount of drug measured in the LPS-coated wells to determine the amount of specifically bound drug.

[0164] Experimental data: Table 7: Detection amount of avibactam sodium in the eluate after the preparations of Example 1 and Comparative Example 1 were bound to LPS (ng / well)

[0165] The results of in vitro bacterial lipopolysaccharide (LPS) binding evaluation experiments (shown in Table 7, using the amount of avibactam sodium detected in the eluate as an indirect indicator) preliminarily confirmed that the Example 1 formulation exhibited significantly higher binding affinity to immobilized LPS than the Comparative Example 1 formulation. Specifically, after deducting nonspecific adsorption, the amount of drug eluted from the Example 1 formulation incubated with LPS (representing the total amount of formulation bound to LPS) was significantly greater than that from Comparative Example 1. This discrepancy directly points to a key difference in the outermost structures of the two formulations: the bacterial LPS-recognizing peptide is specifically incorporated into the outer hydrogel layer of Example 1.

[0166] This enhanced binding ability stems precisely from the biological function of the LPS recognition peptide. LPS, a major component of the outer membrane of Gram-negative bacteria, is a characteristic molecule on the bacterial surface. The LPS recognition peptide used in this invention is designed or screened to specifically recognize and bind to a specific domain or epitope on the LPS molecule. When the Example 1 formulation containing this recognition peptide comes into contact with LPS, the peptide chain tightly binds to the LPS through intermolecular non-covalent interactions (such as electrostatic attraction, hydrogen bonding, and hydrophobic interactions, depending on the peptide's sequence and structure). This specific binding based on molecular recognition gives the Example 1 formulation its ability to actively target LPS.

[0167] In contrast, since the outer hydrogel layer of Comparative Example 1 lacks an LPS-recognizing peptide, its interaction with LPS relies primarily on nonspecific physical adsorption, resulting in significantly lower binding capacity. These experimental results strongly support the innovative design of the present invention, which incorporates an LPS-recognizing peptide into the outer hydrogel layer, thereby endowing the formulation with the potential to target bacterial LPS. This targeting is not only expected to increase local concentration of the drug at the site of infection and reduce exposure to normal tissues, but also, through direct interaction with the bacterial surface, provide a more precise and efficient pathway for subsequent antibacterial treatment.

[0168] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A compound antibacterial preparation containing avibactam sodium, characterized in that: The formulation comprises: An inner layer hydrogel, wherein the inner layer hydrogel is composed of an interpenetrating network structure formed by chitosan and sodium alginate in a mass ratio of 3:2, wherein the molecular weight of the chitosan is 50-70 kDa and the molecular weight of the sodium alginate is 80-120 kDa; the inner layer hydrogel contains avibactam sodium-β-cyclodextrin inclusion complex and meropenem-gelatin-arabic gum microspheres, wherein the amount of avibactam sodium is 0.45-0.55 g and the amount of meropenem is 0.9-1.1 g, relative to the total mass of the polymer of the inner layer hydrogel; An interfacial barrier layer is provided on the outer surface of the inner hydrogel, wherein the interfacial barrier layer is composed of 0.9-1.1 parts of phosphatidylcholine, 0.18-0.22 parts of cholesterol, and 0.018-0.022 parts of membrane transport protein in a mass ratio; An outer layer of hydrogel is provided on the outer surface of the interface barrier layer, wherein the outer layer of hydrogel is composed of a comb-like copolymer of polyacrylic acid and polyethylene glycol, wherein the mass ratio of the main chain to the side chain is 1:3.5; the outer layer of hydrogel contains a bacterial lipopolysaccharide recognition peptide, and the amount thereof is 0.8-1.2% of the total mass of the comb-like copolymer in the outer layer of hydrogel.

2. The compound antibacterial preparation containing avibactam sodium according to claim 1, characterized in that: The inner layer hydrogel forms a triple cross-linked network structure through ionic cross-linking, enzymatic cross-linking and photosensitive cross-linking.

3. The compound antibacterial preparation containing avibactam sodium according to claim 2, characterized in that: The ionic crosslinking is achieved by calcium chloride, and its usage is 15-25% of the total mass of the inner hydrogel polymer; a compound antibacterial preparation containing avibactam sodium and a preparation method thereof; the enzymatic crosslinking is achieved by horseradish peroxidase, and its usage is 0.8-1.2% of the total mass of the inner hydrogel polymer; a compound antibacterial preparation containing avibactam sodium and a preparation method thereof; the photosensitive crosslinking is achieved by 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone, and its usage is 1.8-2.2% of the total mass of the inner hydrogel polymer.

4. The compound antibacterial preparation containing avibactam sodium according to claim 1, characterized in that: The surface of the meropenem-gelatin-arabic gum microspheres is modified with the chronic catalytic enzyme ZO-1.

5. The compound antibacterial preparation containing avibactam sodium according to claim 1, characterized in that: The membrane transporter in the interface barrier layer is selected from P-glycoprotein and / or OATP transporter.

6. A method for preparing the compound antibacterial preparation containing avibactam sodium as claimed in claim 1, characterized in that: The method comprises the following steps: S1. Preparation of avibactam sodium-β-cyclodextrin inclusion complex and meropenem-gelatin-gum arabic microspheres; S2. dispersing the avibactam sodium-β-cyclodextrin inclusion complex and the meropenem-gelatin-gum arabic microspheres in a mixed solution of chitosan and sodium alginate, forming a concentration gradient distribution of the drug particles by gradient centrifugation, and then performing ionic crosslinking, photosensitive crosslinking, and enzymatic crosslinking to form an inner layer hydrogel; S3, preparing an interfacial barrier layer on the surface of the inner hydrogel; S4, preparing an outer layer hydrogel comprising bacterial lipopolysaccharide recognition peptides on the surface of the interface barrier layer; S5. Cut, package and sterilize the formed double-layer hydrogel.

7. The method for preparing a compound antibacterial preparation containing avibactam sodium according to claim 6, characterized in that: When preparing meropenem-gelatin-gum arabic microspheres in step S1, under supercritical CO2-assisted conditions, the pressure is 9-11 MPa, the temperature is 34-36°C, the gelatin solution containing meropenem is added to the gum arabic solution, the pH is adjusted to 3.8-4.2 to form a coagulation, which is then cross-linked with glutaraldehyde and surface modified with chronic catalytic enzyme ZO-1.

8. The method for preparing a compound antibacterial preparation containing avibactam sodium according to claim 6, characterized in that: In step S2, the ionic crosslinking uses a calcium chloride solution with a concentration of 0.8-1.2%; the photosensitive crosslinking is carried out at a wavelength of 360-370 nm and a power density of 8-12 mW / cm 2 The enzymatic cross-linking was performed at 37±1°C for 3.5-4.5 hours.

9. The method for preparing a compound antibacterial preparation containing avibactam sodium according to claim 6, characterized in that: The preparation of the interface barrier layer in step S3 includes: dissolving phosphatidylcholine, cholesterol and membrane transport protein in an organic solvent, evaporating the solvent to form a thin film, and then hydrating the solvent to form a liposome dispersion. The dispersion is sprayed on the surface of the inner hydrogel and allowed to stand at 4±1°C for 1.5-2.5 hours.

10. The method for preparing a compound antibacterial preparation containing avibactam sodium according to claim 6, characterized in that: The preparation of the outer layer hydrogel in step S4 includes: reacting polyacrylic acid with polyethylene glycol to prepare a comb-like copolymer; mixing the comb-like copolymer with bacterial lipopolysaccharide recognition peptide, N,N'-methylenebisacrylamide and a photoinitiator, and then coating the mixture on the surface of the interface barrier layer, performing photoinitiated crosslinking, and then degassing under a vacuum of 0.04-0.06 MPa for 25-35 minutes.

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