A sustained-release formulation of teicoplanin for injection and its preparation method

Abstract

This invention belongs to the field of biomedicine and discloses a teicoplanin sustained-release injection, its preparation method, and its application. The injection consists of the active ingredient teicoplanin and a polylactic-co-glycolic acid (PLGA) carrier in a specific ratio (lactic acid:glycolic acid molar ratio 75:25–85:15, molecular weight 10,000–50,000 Da), with a drug-to-carrier weight ratio of 1:3–1:5, forming sustained-release microspheres with a particle size of 10–50 μm. The surface of the microspheres is coated with a composite stabilizing layer containing polyvinyl alcohol (PVA, 0.5–2% w / w) and mannitol (1–5% w / w). Combined with a gradient temperature curing process and freeze-drying protection technology, the burst release effect is significantly reduced (24-hour release ≤50%), achieving a cumulative release of ≥80% over 7 days. Furthermore, the viscosity of the dispersion medium after reconstitution is controlled at 10–50 mPa·s (25℃), ensuring needle penetration. The preparation method improves the drug encapsulation efficiency (>90%) and stability by optimizing the W / O / W emulsification process, low-temperature solvent evaporation and surface coating steps, thus solving the problems of high burst release, low encapsulation efficiency and easy aggregation during storage of traditional PLGA microspheres.

Description

Technical Field

[0001] This invention belongs to the field of biomedicine and provides a teicoplanin sustained-release injection and its preparation method. Background Technology

[0002] Teicoplanin is a glycopeptide antibiotic with potent antibacterial activity against Gram-positive bacteria (including methicillin-resistant Staphylococcus aureus (MRSA)). Clinically, it is widely used to treat deep tissue infections such as bone and joint infections and infective endocarditis. However, existing teicoplanin formulations are primarily injectable, requiring multiple daily doses (usually every 12-24 hours), leading to poor patient compliance, large fluctuations in blood drug concentrations, and the potential for local tissue irritation from frequent injections. For chronic infections requiring long-term treatment (such as bone and joint infections), existing formulations are insufficient to meet the need for sustained and effective antibacterial activity.

[0003] In recent years, sustained-release microsphere technology using polylactic-co-glycolic acid copolymer (PLGA) as a carrier has been explored for the sustained-release delivery of antibiotics. However, existing PLGA-based sustained-release formulations still have significant drawbacks:

[0004] 1. Insufficient control of burst release effect: Most PLGA microspheres release more than 50% within 24 hours, which cannot meet the need for "rapidly reaching effective concentration and continuous release" in the treatment of deep infections. High burst release may lead to early toxicity risks.

[0005] 2. Poor drug encapsulation efficiency and stability: Teicoplanin is a hydrophilic drug. Microspheres prepared by traditional emulsification methods are prone to low encapsulation efficiency (usually <70%) due to drug diffusion, and microspheres are prone to aggregation or drug degradation during storage.

[0006] 3. Defects in formulation process: Existing microsphere solidification processes (such as isothermal evaporation) are prone to causing uneven porosity inside the microspheres, affecting the reproducibility of the release curve; the microsphere structure is prone to collapse during freeze drying, resulting in poor dispersibility and high viscosity (>50 mPa·s) after reconstitution, making it difficult to meet the requirements for injection permeability.

[0007] 4. Limitations in excipient compatibility: Commonly used surfactants (such as single PVA) are difficult to balance microsphere stability and burst release control, and lack protective designs for the chemical stability of teicoplanin (such as oxidation or metal ion catalytic degradation).

[0008] To address the aforementioned issues, there is an urgent need to develop a teicoplanin sustained-release injection with precise release kinetics, high encapsulation efficiency, and good stability. Summary of the Invention

[0009] To address the aforementioned issues, we disclose an injectable teicoplanin sustained-release formulation and its preparation method. This invention, by optimizing the composition of the PLGA carrier, the microsphere structure design, and the preparation process, combined with composite stabilizing layer coating technology, successfully overcomes the bottlenecks of existing technologies, providing a safer and longer-acting treatment option for deep infections caused by MRSA.

[0010] This invention includes the following specific technical solutions:

[0011] A teicoplanin extended-release injection comprising: components 1) and 2), wherein

[0012] 1) Teicoplanin active ingredient;

[0013] 2) A biodegradable polymer carrier, wherein the carrier is a polylactic acid-glycolic acid copolymer (PLGA) with a lactic acid to glycolic acid molar ratio of 75:25 to 85:15;

[0014] The weight ratio of 1) to 2) is 1:3 to 1:5;

[0015] The combination of 1) and 2) forms sustained-release microspheres with a particle size of 10-50 μm;

[0016] The surface of the microspheres is coated with a stabilizing layer containing polyvinyl alcohol (PVA) and mannitol, wherein PVA accounts for 0.5-2% w / w of the total weight of the microspheres and mannitol accounts for 1-5% w / w of the total weight of the microspheres.

[0017] The injectable agent has sustained-release properties, achieving a release rate of ≤50% within 24 hours and a cumulative release rate of ≥80% over 7 days after subcutaneous or intramuscular injection.

[0018] The injection is a lyophilized powder for injection, and the viscosity of the dispersion medium after reconstitution is 10-50 mPa·s, measured at 25℃.

[0019] Furthermore, the PLGA in the aforementioned teicoplanin sustained-release injection has a molecular weight of 10,000-50,000 Da, an intrinsic viscosity of 0.2-0.6 dL / g, and is measured in chloroform at 25°C.

[0020] The present invention also discloses a method for producing the above-mentioned sustained-release injection, comprising the following steps:

[0021] a) Dissolve PLGA in dichloromethane to form an organic phase of 5-15% w / v;

[0022] b) Disperse teicoplanin in an aqueous phase containing 1-3% w / v PVA and sonicate until the particle size is ≤5μm;

[0023] c) The organic phase is injected into the aqueous phase at a stirring speed of 800-1200 rpm to form a W / O / W emulsion;

[0024] d) Curing microspheres using a gradient temperature rise process: maintain 10-15℃ for the first 2 hours, then raise the temperature to 30-35℃ at a rate of 0.5℃ / min and maintain it for 2-4 hours;

[0025] e) Evaporate the solvent at 2-8℃ for 12-24h, collect the microspheres by filtration through a sieve with a pore size of 5-20μm, wash them three times each with deionized water and 0.1% w / v mannitol aqueous solution, and vacuum dry them at 25-30℃ until the water content is ≤3%;

[0026] f) Immerse the microspheres in an aqueous solution containing 1-5% w / v mannitol and stir for 30-60 min to form a surface coating layer;

[0027] g) After adding 2-5% w / w trehalose as a freeze-drying protectant, freeze-dry the product.

[0028] Furthermore, in the above-mentioned method for preparing teicoplanin sustained-release injection, optionally, in step b), a metal ion chelating agent is further added, wherein the metal ion chelating agent accounts for 0.01-0.1% w / w of the final injection weight.

[0029] Furthermore, in the above-mentioned method for preparing teicoplanin sustained-release injection, the metal ion chelating agent is selected from calcium sodium ethylenediaminetetraacetate or sodium citrate.

[0030] Furthermore, in the above-mentioned method for preparing teicoplanin sustained-release injection, in step c), the formation of the W / O / W emulsion is carried out under nitrogen protection.

[0031] Furthermore, in the above-mentioned method for preparing teicoplanin sustained-release injection, the freeze-drying process in step g) is carried out at a temperature of -40°C to -60°C, and the freeze-drying time is not less than 24 hours.

[0032] The present invention also discloses the use of the above-mentioned sustained-release injection in the preparation of drugs for treating osteoarthritis or infective endocarditis caused by methicillin-resistant Staphylococcus aureus (MRSA).

[0033] Compared with the prior art, the present invention has the following outstanding advantages:

[0034] This invention significantly improves the performance of teicoplanin sustained-release injection through innovative formulation design and process optimization, with the following specific effects:

[0035] 1. Precise control of drug release kinetics

[0036] Low burst release effect: By optimizing the hydrophobicity and microsphere structure of the PLGA carrier (lactic acid: glycolic acid = 75:25–85:15) and combining it with a gradient temperature curing process (initial low temperature curing at 10–15℃ + slow temperature increase), the burst release effect is significantly reduced, achieving a release of ≤50% within 24 hours, thus avoiding the toxicity risk caused by excessively high blood drug concentrations in the early stages.

[0037] Long-lasting release: The cumulative release over 7 days is ≥80%, meeting the need for sustained effective antibacterial concentrations in the treatment of deep infections. This allows for an extension of the dosing frequency to once a week, significantly improving patient compliance.

[0038] 2. High encapsulation efficiency and stability

[0039] Highly efficient drug loading: Teicoplanin is dispersed by ultrasound to a particle size of ≤5μm, and then encapsulated to >90% by a W / O / W emulsification process combined with a low-temperature solvent evaporation method, reducing drug waste.

[0040] Enhanced physicochemical stability: The microspheres are coated with a PVA-mannitol composite layer (PVA 0.5–2% w / w, mannitol 1–5% w / w), which inhibits microsphere aggregation and drug degradation; with the addition of trehalose freeze-drying protectant, the microspheres have an intact structure after freeze-drying, excellent reconstitution and dispersibility, and extended shelf life.

[0041] 3. Advantages of optimized formulation process

[0042] High reproducibility of release curves: The gradient heating process avoids the problem of uneven porosity inside the microspheres, ensuring consistent release behavior between batches.

[0043] Excellent needle penetration: By controlling the microsphere particle size (10–50 μm) and the viscosity after reconstitution (10–50 mPa·s, 25℃), the injection can be made to pass smoothly through commonly used clinical needles (such as 21–23G), reducing the risk of local irritation.

[0044] 4. Clinical treatment advantages

[0045] Targeting deep infections: After subcutaneous or intramuscular injection, the microspheres form a local drug reservoir, slowly releasing teicoplanin to the lesion (such as bone, joints, or endocardium), increasing the drug concentration at the site of infection and reducing systemic exposure side effects.

[0046] Expanded indications: Particularly suitable for refractory infections such as bone and joint infections and infective endocarditis caused by MRSA that require long-term treatment, filling the gap in existing formulations that cannot achieve weekly dosing.

[0047] In summary, this invention combines excellent sustained-release properties, stability, and clinical applicability, providing a highly efficient and safe long-acting drug delivery solution for the treatment of deep bacterial infections. Attached Figure Description

[0048] Figure 1 Comparison chart of particle size D50 (μm);

[0049] Figure 2 Encapsulation efficiency (%) comparison chart;

[0050] Figure 3 Comparison chart of 24-hour burst release (%). Detailed Implementation

[0051] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] To ensure the repeatability of experiments and the reliability of data, the various test methods involved in this invention are performed according to the following standardized procedures.

[0053] 1. Particle size distribution determination

[0054] Instrument: Malvern Mastersizer 3000 laser particle size analyzer

[0055] Sample processing:

[0056] Take 10 mg of lyophilized microspheres, disperse them in 1% w / v Tween-80 aqueous solution (5 mL), and sonicate (40 kHz, 100 W) for 1 min to avoid bubble interference.

[0057] Test conditions:

[0058] Refractive index of the dispersion medium: 1.33 (water);

[0059] Particle refractive index: 1.50 (PLGA);

[0060] Light blocking rate range: 5-15%;

[0061] Number of measurements: 3 independent parallel experiments, and the average value of D50 (median particle size) was taken.

[0062] 2. Encapsulation efficiency determination

[0063] Instrument: Agilent 1260 High Performance Liquid Chromatograph (HPLC)

[0064] Chromatographic conditions:

[0065] Chromatographic column: C18 column (4.6×250mm, 5μm);

[0066] Mobile phase: Acetonitrile-0.1% phosphoric acid aqueous solution (25:75, v / v);

[0067] Flow rate: 1.0 mL / min;

[0068] Detection wavelength: 280nm;

[0069] Column temperature: 30℃;

[0070] Injection volume: 20 μL.

[0071] Sample processing:

[0072] Total drug content determination: Accurately weigh 10 mg of microspheres, dissolve in 1 mL of dimethyl sulfoxide (DMSO), vortex until completely dissolved, filter through a 0.22 μm filter membrane, and dilute to the HPLC detection linear range (0.1-1.0 mg / mL).

[0073] Determination of free drug content: The washing solution (deionized water and mannitol solution) from the microsphere preparation process was combined, concentrated, and then analyzed by HPLC to determine the amount of unencapsulated drug.

[0074] Encapsulation efficiency E is calculated using the following formula:

[0075]

[0076] 3. Determination of burst release and cumulative release

[0077] Release medium: pH 7.4 phosphate buffer (containing 0.1% w / v SDS, simulating physiological conditions)

[0078] Instrument: RCZ-8M drug dissolution apparatus (paddle method, 100 rpm)

[0079] Test steps:

[0080] Accurately weigh 50 mg of microspheres, place them in a dialysis bag (molecular weight cutoff 10 kDa), and immerse them in 900 mL of release medium;

[0081] At a constant temperature of 37±0.5℃, 5 mL samples were taken at 0.5, 1, 2, 4, 8, 12, 24 h and daily thereafter (with an equal volume of fresh medium added at the same time);

[0082] The concentration of teicoplanin was determined by HPLC after the sample was filtered through a 0.22 μm filter membrane, and the cumulative release rate was calculated.

[0083] 4. Reconstitution viscosity determination

[0084] Instrument: Brookfield DV2T rotational viscometer (compatible with LV-4 rotor)

[0085] Sample processing:

[0086] Take 100 mg of lyophilized microspheres, add 2 mL of water for injection, vortex for 1 min, and let stand for 5 min to form a homogeneous suspension.

[0087] Test conditions:

[0088] Temperature: 25±0.1℃ (water bath temperature control);

[0089] Rotational speed: 60 rpm;

[0090] Measurement time: 3 minutes, steady-state viscosity value;

[0091] The measurements were performed in three parallel trials, and the average value was taken.

[0092] 5. Storage stability test

[0093] Accelerated testing conditions:

[0094] Temperature: 40±2℃;

[0095] Humidity: 75±5% RH;

[0096] Packaging: Sealed with a semi-permeable aluminum-plastic composite film;

[0097] Timeframe: 0, 1, 2, or 3 months.

[0098] Testing indicators:

[0099] Appearance: Visually inspect for color changes, clumping, or aggregation of microspheres;

[0100] Encapsulation efficiency: determined according to the above HPLC method;

[0101] Reconstitution properties: Dispersion uniformity was assessed using viscosity measurement methods;

[0102] Microbial limits: Tested according to General Chapter 1105 of Part IV of the 2020 edition of the Chinese Pharmacopoeia.

[0103] Example 1

[0104] Preparation of Teicoplanin Extended-Release Injection

[0105] Step a: Weigh 4.0g of PLGA (Suzhou Beike Nanotechnology Co., Ltd.) with a molecular weight of 30,000 Da and a lactic acid:glycolic acid molar ratio of 80:20, and dissolve it in 40mL of dichloromethane to form a 10% w / v organic phase.

[0106] Step b: Disperse 1.0g of teicoplanin raw material (Wuhan Dingxintong Pharmaceutical Co., Ltd.) in 100mL of aqueous phase containing 2% w / v PVA (Xi'an Tianzheng Pharmaceutical Excipients Co., Ltd. Pharmaceutical Grade PVA88 CP2020), and sonicate for 30min (power 200W, frequency 40kHz) to obtain a uniform suspension with a particle size ≤3μm.

[0107] Step c: Under nitrogen protection, the organic phase is slowly injected into the aqueous phase at a stirring speed of 1000 rpm to form a W / O / W emulsion.

[0108] Step d: Gradient temperature curing: maintain 12℃ for the first 2 hours, then increase the temperature to 32℃ at 0.5℃ / min and maintain for 3 hours.

[0109] Step e: Evaporate the solvent at 4℃ for 18h, filter through a 15μm sieve, wash three times with deionized water and 0.1% mannitol aqueous solution, and vacuum dry (28℃, 24h) until the water content is 2.5%.

[0110] Step f: Immerse the microspheres in a 3% w / v mannitol solution and stir for 45 min to form a surface coating layer.

[0111] Step g: Add 3% w / w trehalose and freeze-dry at -50℃ for 28 hours to obtain lyophilized powder for injection.

[0112] Key parameter testing:

[0113] Particle size distribution: D50 = 28 μm (measured by laser particle size analyzer);

[0114] Encapsulation efficiency: 93.2% (determined by HPLC);

[0115] Burst release: 42% in 24 hours, 85% cumulative release over 7 days;

[0116] Reconstitution viscosity: 35 mPa·s (25℃, rotational viscometer);

[0117] Storage stability: After 3 months at 40℃ / 75% RH, the encapsulation efficiency decreased by <5%, and no visible aggregation was observed.

[0118] Example 2

[0119] High PLGA ratio formulation (drug:carrier = 1:5)

[0120] Step a: Select 5.0 g of PLGA (molecular weight 50,000 Da) with a lactic acid:glycolic acid ratio of 85:15 and dissolve it in 50 mL of dichloromethane (10% w / v).

[0121] Step b: 1.0 g of teicoplanin was dispersed in a 1% w / v PVA aqueous phase, and the particle size was ≤4 μm after sonication.

[0122] Step c: Other steps are the same as in Example 1. The final microsphere particle size D50 = 45 μm, encapsulation efficiency 91.5%, 24-hour release 38%, and 7-day release 88%.

[0123] Example 3

[0124] Low PLGA ratio formulation (drug:carrier = 1:3)

[0125] Step a: Select 3.0 g of PLGA (molecular weight 10,000 Da) with a lactic acid:glycolic acid ratio of 75:25 and dissolve it in 20 mL of dichloromethane (15% w / v).

[0126] Step b: Disperse 1.0 g of teicoplanin in a 3% w / v PVA aqueous phase and add 0.05% calcium sodium ethylenediaminetetraacetate.

[0127] Step c: In step d, the temperature is raised to 35℃ and maintained for 4 hours. The final microsphere particle size D50 is 12μm, the encapsulation efficiency is 89.7%, the release rate is 47% after 24 hours, and the release rate is 82% after 7 days.

[0128] Comparative Example 1

[0129] Comparative Example 1: PLGA molar ratio outside the range (lactic acid:glycolic acid = 70:30)

[0130] Preparation method: Except that the PLGA molar ratio is adjusted to 70:30, the rest is the same as in Example 1.

[0131] Results: The burst release rate reached 65% in 24 hours, while the cumulative release rate was only 72% in 7 days. The microspheres were uneven in size (D50 = 50 μm, span > 2).

[0132] Comparative Example 2

[0133] The drug carrier ratio is outside the range (1:2).

[0134] Preparation method: PLGA 2.0g and teicoplanin 1.0g were mixed (1:2), and other steps were the same as in Example 1.

[0135] Results: The encapsulation rate was only 68%, the release rate was 58% after 24 hours, the microspheres were severely aggregated after freeze-drying, and the reconstitution viscosity was >80 mPa·s.

[0136] Comparative Example 3

[0137] Gradient heating process not used

[0138] Preparation method: Step d is changed to constant temperature curing at 30℃ for 6 hours, and the rest is the same as in Example 1.

[0139] Results: The porosity of the microspheres varied greatly, and the release amount fluctuated between batches over 7 days (75%-88%), with a 24-hour burst release of 52%.

[0140] Comparative Example 4

[0141] No trehalose freeze-drying protectant added

[0142] Preparation method: omit the trehalose in step g, and freeze-dry directly. Other steps are the same as in Example 1.

[0143] Results: The collapse rate of microspheres after freeze-drying was >30%, the reconstitution dispersibility was poor, and the encapsulation rate decreased by 12% after 1 month of storage.

[0144] Analysis example

[0145] The test results of the summarized examples and comparative examples are shown in Table 1 below. Figure 1-3 As shown.

[0146] Table 1 Test Results

[0147]

[0148]

[0149] Note:

[0150] 1. Items marked with "*": indicate key parameters that deviate from the technical solution of this invention;

[0151] 2. Storage stability: The accelerated test conditions were 40℃ / 75% RH. The example was tested for 3 months, and the comparative example was tested for 1 month (due to time constraints, the comparative example was only tested for 1 month, but it was sufficient to observe the performance degradation trend).

[0152] 3. Reconstitution viscosity: The clinically acceptable range is 10-50 mPa·s (>50 mPa·s may cause injection blockage);

[0153] 4. 7-day release of Comparative Example 3: Due to defects in the curing process, there were batch-to-batch fluctuations (±8%), which did not meet the quality control standards (RSD < 5%).

[0154] As can be seen from the test results in Table 1 above, this invention systematically solves the long-standing technical problems (high burst release, low encapsulation rate, and poor stability) of PLGA-based teicoplanin sustained-release formulations through a combination of key parameter optimization and process innovation.

[0155] 1. Synergistic control of PLGA composition and drug carrier ratio (Example 1 vs. Comparative Examples 1-2)

[0156] Example 1: Using PLGA (molecular weight 30kDa) with a lactic acid:glycolic acid ratio of 80:20 and a drug:carrier ratio of 1:4, combined with a gradient temperature process, a 42% burst release was achieved in 24 hours, an 85% release was achieved in 7 days, and an encapsulation rate of 93.2%.

[0157] Comparative Example 1 (PLGA molar ratio out of range): When the PLGA molar ratio was adjusted to 70:30 (glycolic acid ratio too high), the hydrophilicity of PLGA increased, leading to a surge in burst release to 65% (24h), and insufficient cumulative release (72% over 7 days). This demonstrates that the lactate ratio needs to be ≥75% to maintain sufficient hydrophobicity and inhibit early drug diffusion.

[0158] Comparative Example 2 (Drug-Carrier Ratio 1:2): Reducing the PLGA ratio resulted in excessively high drug loading, with an encapsulation efficiency of only 68%, a burst release of 58%, and excessive viscosity after reconstitution. Validation shows that a drug:carrier ratio of 1:3–1:5 is the critical window for balancing drug loading and sustained release.

[0159] Summarize:

[0160] In existing technologies, the composition of PLGA and the drug ratio are usually set based on experience (such as a conventional 50:50 or a random ratio). This invention, through experiments, has found that the synergistic effect of a lactic acid ratio of 75–85% and a drug carrier ratio of 1:3–1:5 can precisely control the balance between drug diffusion resistance and PLGA degradation rate without sacrificing drug loading.

[0161] 2. The core role of gradient temperature curing process (Example 1 vs. Comparative Example 3)

[0162] Example 1: Using an initial low temperature curing method of 12℃ followed by slow heating to 32℃, the microspheres exhibited uniform pore distribution, with batch-to-batch release differences of <5% (7-day release amount of 85±2%).

[0163] Comparative Example 3 (Isothermal Curing): Curing at an isothermal temperature of 30℃ resulted in an excessively rapid solvent evaporation rate. The hard shell on the surface of the microspheres hindered the escape of the internal solvent, forming irregular pores. The release varied greatly between batches (75-88% over 7 days), with a burst release of 52%. This demonstrates that gradient heating is a necessary means to control the uniformity of the microsphere structure.

[0164] Summarize:

[0165] Traditional PLGA microsphere curing methods often employ isothermal processes. This invention, however, proposes a gradient heating strategy for the first time. This involves slowly forming a dense outer shell at low temperatures, followed by gradual heating to promote the gentle evaporation of the internal solvent, preventing pore collapse or bursting. This process requires a specific molecular weight of PLGA (10k–50kDa) and a suitable solvent system (dichloromethane) to be effective.

[0166] 3. Synergistic effect of composite stabilizing layer and freeze-drying protection (Example 1 vs. Comparative Example 4)

[0167] Example 1: The microspheres were coated with PVA (2%) + mannitol (3%) and protected by trehalose freeze drying. After 3 months of storage, the encapsulation rate decreased by <5%, and the reconstitution and dispersibility were excellent (viscosity 35 mPa·s).

[0168] Comparative Example 4 (without trehalose): After freeze-drying, the microsphere collapse rate was >30%, the encapsulation rate decreased by 12% after 1 month of storage, and the reconstitution and dispersibility were poor. This indicates that trehalose inhibits ice crystal damage through glass transition and, together with the PVA-mannitol layer, maintains the integrity of the microspheres.

[0169] Summarize:

[0170] In existing technologies, PVA is often used alone as an emulsifier, while this invention innovatively introduces mannitol as a stabilizer. Its hydroxyl groups form a hydrogen bond network with PVA, enhancing the mechanical strength of the microsphere surface. At the same time, the low-temperature protection effect of trehalose and the surface coating layer form a dual barrier, solving the industry problem of microsphere structure collapse and poor storage stability during freeze-drying.

[0171] 4. The added value of metal ion chelating agents (Example 3)

[0172] Example 3: Adding 0.05% calcium sodium ethylenediaminetetraacetate in step b increased the encapsulation efficiency to 89.7% (compared to <85% without addition). The chelating agent binds metal ions (such as Fe) in water. 3+ Cu 2+ It inhibits the oxidative degradation of teicoplanin and prolongs the shelf life of the formulation.

[0173] Existing technology has shortcomings: traditional PLGA microspheres neglect the chemical stability of drugs, especially the sensitivity of teicoplanin to metal ions. This invention establishes a multiple stability assurance mechanism through chelating agents, low-temperature processing, and inert gas protection (nitrogen environment in step c).

[0174] Animal experimental test cases

[0175] Animal models:

[0176] A model of MRSA bone and joint infection was established using SD rats (200-250g, purchased from Nanjing Zhishuyantu Biotechnology Co., Ltd.) (MRSA bacterial suspension was injected into the tibia, and the drug was administered 48 hours after infection).

[0177] Grouping and Dosing:

[0178] Experimental group: 10 animals, subcutaneously injected with sustained-release microspheres prepared in Example 1 (teicoplanin dose 20 mg / kg);

[0179] Control group: 10 animals, intravenously injected with conventional teicoplanin injection (daily administration, total dose 20mg / kg / day × 7 days, Zhejiang Hisun Pharmaceutical Co., Ltd.);

[0180] Control group: 5 animals, injected with physiological saline.

[0181] Testing indicators:

[0182] Blood drug concentration: Blood samples were collected at 0.5h, 1h, 6h, 12h, 24h after administration and daily up to day 7. Teicoplanin concentration was determined by HPLC.

[0183] Tissue drug concentration: Animals were sacrificed on day 7, and infected bones and joints, heart (simulating target tissue of endocarditis) and liver (representative of whole-body exposure) were taken, homogenized, and drug concentration was measured.

[0184] Antibacterial effect: Take tissue homogenate from the infected site, spread it on MH agar plates, and calculate the colony count (CFU / g).

[0185] Summary of experimental results:

[0186] The experimental group had stable blood drug concentrations with peak concentration (Cmax) < 10 μg / mL (compared to Cmax > 30 μg / mL in the control group), and reduced systemic exposure.

[0187] Maintain drug concentrations >5 μg / g (5 times the MIC = 1 μg / mL) in infected bone and joint tissues until day 7;

[0188] Colony count reduced to <10 3 CFU / g (in the control group, due to fluctuations caused by intermittent dosing, the colony count repeatedly increased to >10). 5 CFU / g).

[0189] Conclusion: The sustained-release microspheres prepared in this invention can form a drug reservoir locally, maintain an effective concentration at the site of infection, and reduce systemic side effects.

[0190] The above are merely a few preferred embodiments of the present invention, described in a relatively specific and detailed manner, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A teicoplanin sustained-release injection, characterized in that, It contains: components 1) and 2), wherein 1) Teicoplanin active ingredient; 2) A biodegradable polymer carrier, wherein the carrier is a polylactic acid-glycolic acid copolymer (PLGA) having a lactic acid to glycolic acid molar ratio of 75:25 to 85:15; The weight ratio of 1) to 2) is 1:3 to 1:5; The combination of 1) and 2) forms sustained-release microspheres with a particle size of 10-50 μm; The surface of the microspheres is coated with a stabilizing layer containing polyvinyl alcohol (PVA) and mannitol, wherein PVA accounts for 0.5-2% w / w of the total weight of the microspheres and mannitol accounts for 1-5% w / w of the total weight of the microspheres. The injectable agent achieves sustained-release characteristics of ≤50% release within 24 hours and ≥80% cumulative release over 7 days after subcutaneous or intramuscular injection; The injection is a lyophilized powder for injection, and the viscosity of the dispersion medium after reconstitution is 10-50 mPa•s, measured at 25℃. The PLGA has a molecular weight of 10,000-50,000 Da and an intrinsic viscosity of 0.2-0.6 dL / g, as determined in chloroform at 25°C. The preparation method of the above-mentioned sustained-release injection includes the following steps: a) Dissolve PLGA in dichloromethane to form an organic phase of 5-15% w / v; b) Disperse teicoplanin in an aqueous phase containing 1-3% w / v PVA and sonicate until the particle size is ≤5μm; c) The organic phase is injected into the aqueous phase at a stirring speed of 800-1200 rpm to form a W / O / W emulsion; d) Curing microspheres using a gradient temperature rise process: maintain 10-15℃ for the first 2 hours, then raise the temperature to 30-35℃ at a rate of 0.5℃ / min and maintain it for 2-4 hours; e) Evaporate the solvent at 2-8℃ for 12-24 hours, collect the microspheres by filtration through a sieve with a pore size of 5-20 μm, wash them three times each with deionized water and 0.1% w / v mannitol aqueous solution, and vacuum dry them at 25-30℃ until the water content is ≤3%; f) Immerse the microspheres in an aqueous solution containing 1-5% w / v mannitol and stir for 30-60 min to form a surface coating layer; g) Add 2-5% w / w trehalose as a freeze-drying protectant before freeze-drying; In step b), a metal ion chelating agent is further added, wherein the metal ion chelating agent accounts for 0.01-0.1% w / w of the final injection weight; The metal ion chelating agent is selected from sodium calcium ethylenediaminetetraacetate or sodium citrate. In step c), the formation of the W / O / W emulsion is carried out under nitrogen protection; The freeze-drying process in step g) is carried out at a temperature of -40°C to -60°C, and the freeze-drying time is not less than 24 hours.

2. The use of the sustained-release injection as described in claim 1 in the preparation of a medicament for treating bone and joint infections caused by methicillin-resistant Staphylococcus aureus (MRSA).

3. The use of the sustained-release injection as described in claim 1 in the preparation of a medicament for treating infective endocarditis caused by methicillin-resistant Staphylococcus aureus (MRSA).

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