A bilayer core-shell nanoparticle composite thermosensitive gel for postoperative analgesia, its preparation method and application

Abstract

This invention relates to the fields of biomedicine and nanomaterials technology, and provides a bilayer core-shell nanoparticle composite thermosensitive gel for postoperative analgesia, its preparation method, and its applications. The bilayer core-shell nanoparticles comprise: a core of PLGA nanoparticles loaded with magnesium, and a shell of a lipid bilayer loaded with bupivacaine. The composite thermosensitive gel is made by uniformly dispersing the bilayer core-shell nanoparticles in a thermosensitive gel material. By constructing a structure with a lipid shell loaded with bupivacaine and a PLGA core loaded with magnesium, and combining it with a thermosensitive gel, this invention achieves rapid release of bupivacaine for acute postoperative analgesia, and sustained slow release of magnesium ions for long-term anti-inflammatory and repairing effects. This perfectly meets the temporal requirements of postoperative pain management and has broad clinical application prospects.

Description

Technical Field

[0001] This invention relates to the fields of biomedicine and nanomaterials technology, specifically a bilayer core-shell nanoparticle composite thermosensitive gel for postoperative analgesia, its preparation method, and its application. Background Technology

[0002] Postoperative pain management is a crucial aspect of enhanced recovery after surgery (ERAS). Currently, commonly used postoperative analgesics include local anesthetics (such as bupivacaine) and nonsteroidal anti-inflammatory drugs (NSAIDs). However, a single drug cannot simultaneously meet the sequential needs of potent acute analgesia and subsequent anti-inflammatory repair. Bupivacaine has a limited duration of action, while systemic anti-inflammatory drugs have significant side effects.

[0003] In recent years, nanodelivery systems have offered new solutions to this problem. Existing technologies have reported encapsulating different drugs within core-shell structures. For example, a core-shell-based drug composition loads meloxicam onto liposomes and bupivacaine onto PLGA nanoparticles, achieving sequential drug release. Furthermore, further combining nanoparticles with thermosensitive gels to prolong local retention time is also a known strategy, such as dispersing antitumor nanoparticles in mPEG-PLGA thermosensitive gels.

[0004] However, no existing technology has been found to combine local anesthetics with magnesium ions (Mg). 2+ Reports have documented precise, time-sequential release of drugs through a specific core-shell structure. However, precisely controlling the release rates of two drugs to perfectly match the pathophysiological needs of different stages of postoperative pain, particularly utilizing the anti-inflammatory and pro-repair properties of magnesium ions, remains a limitation of current technologies. Therefore, there is an urgent need to provide a bilayer core-shell nanoparticle composite thermosensitive gel for postoperative analgesia, along with its preparation method and applications, to overcome the shortcomings in current practical applications. Summary of the Invention

[0005] The purpose of this invention is to provide a bilayer core-shell nanoparticle composite thermosensitive gel for postoperative analgesia, its preparation method, and its application, aiming to solve the problems in the background art mentioned above.

[0006] This invention is achieved by providing a bilayer core-shell nanoparticle, wherein the nanoparticle comprises: The core is a PLGA nanoparticle loaded with magnesium. The outer shell is a lipid bilayer loaded with bupivacaine, which wraps around the outer surface of the core.

[0007] As a further aspect of the present invention: the magnesium agent is magnesium sulfate; The lipid bilayer is composed of DSPC, cholesterol, and DSPE-PEG.

[0008] As a further aspect of the present invention, the molar ratio of DSPC, cholesterol and DSPE-PEG is 60:35:5.

[0009] The present invention also provides a method for preparing the above-mentioned bilayer core-shell nanoparticles, comprising the following steps: Step 1: Prepare PLGA nanoparticle cores loaded with magnesium agent using the double emulsion-solvent evaporation method; Step 2: Using the thin film hydration method, bupivacaine and lipid materials are made into a lipid film, and then an aqueous solution of the PLGA nanoparticle core prepared in Step 1 is added for hydration. The lipid bilayer loaded with bupivacaine is self-assembled and encapsulates the PLGA core to obtain bilayer core-shell nanoparticles.

[0010] As a further aspect of the present invention: the dosage of magnesium in step 1 is 10-30 mg / mL PLGA solution; In step 2, the dosage of bupivacaine is 5-15 mg / mL.

[0011] The present invention also provides a bilayer core-shell nanoparticle composite thermosensitive gel, comprising the above-mentioned bilayer core-shell nanoparticles and thermosensitive gel material.

[0012] As a further aspect of the present invention: the temperature-sensitive gel material is a PLGA-PEG-PLGA triblock copolymer.

[0013] The present invention also provides a method for preparing the above-mentioned bilayer core-shell nanoparticle composite thermosensitive gel, wherein the aqueous dispersion of the above-mentioned bilayer core-shell nanoparticles is mixed uniformly with PLGA-PEG-PLGA thermosensitive gel material at low temperature to obtain the bilayer core-shell nanoparticle composite thermosensitive gel.

[0014] The present invention also provides the use of the bilayer core-shell nanoparticles as described above or the above-described bilayer core-shell nanoparticle composite thermosensitive gel in the preparation of drugs for postoperative analgesia and / or anti-inflammatory purposes.

[0015] As a further aspect of the present invention: in an in vitro release test, the bilayer core-shell nanoparticles or bilayer core-shell nanoparticle composite thermosensitive gel showed that bupivacaine was rapidly released within 48 hours, while magnesium was continuously released within 7 to 14 days.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention achieves the sequential release of two drugs by constructing a bilayer core-shell nanoparticle with a lipid shell loaded with bupivacaine and a PLGA core loaded with magnesium, combined with a thermosensitive gel. Bupivacaine is rapidly released from the outer lipid layer to meet the demand for potent analgesia in the postoperative acute phase, while magnesium ions are continuously and slowly released from the inner PLGA core to exert long-term anti-inflammatory and repair effects. This formulation perfectly matches the pathophysiological process of postoperative pain management, reduces the frequency of administration, improves patient compliance, and reduces the side effects of systemic medication. Detailed Implementation

[0017] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0018] The present invention will be further explained below with reference to specific embodiments.

[0019] This invention provides a bilayer core-shell nanoparticle, the nanoparticle comprising: The core is a magnesium-loaded PLGA nanoparticle (magnesium@PLGA). The outer shell is a lipid bilayer loaded with bupivacaine (bupivacaine@lipid), which encapsulates the outer surface of the magnesium agent@PLGA core.

[0020] In a more specific example, the magnesium agent is magnesium sulfate; The lipid bilayer is composed of DSPC (distearylphosphatidylcholine), cholesterol, and DSPE-PEG (distearylphosphatidylethanolamine-polyethylene glycol); Preferably, the molar ratio of DSPC, cholesterol, and DSPE-PEG is 60:35:5.

[0021] The present invention also provides a method for preparing the above-mentioned bilayer core-shell nanoparticles, comprising the following steps: Step 1, Core layer preparation (magnesium agent@PLGA): Using the double emulsion-solvent evaporation method, magnesium sulfate aqueous solution is used as the inner aqueous phase and added to PLGA dissolved in an organic solvent to emulsify and form a primary emulsion. Then, it is transferred to the outer aqueous phase to form a double emulsion. The organic solvent is evaporated and collected by centrifugation to obtain the PLGA nanoparticle core loaded with magnesium sulfate. The dosage of magnesium agent is 10-30 mg / mL of PLGA solution; the dosage of bupivacaine is 5-15 mg / mL. Step 2, Shell Loading and Encapsulation (Bupivacaine@Lipid Shell): Using the thin film hydration method, bupivacaine and lipid materials (DSPC / cholesterol / DSPE-PEG) are dissolved in an organic solvent and rotary evaporated to form a lipid film; then the magnesium agent@PLGA nanoparticle hydration medium prepared in step (1) is added for hydration, so that the lipid bilayer self-assembles into vesicles during the hydration process, while bupivacaine is loaded into the lipid bilayer and encapsulates the PLGA core to obtain the bilayer core-shell nanoparticles.

[0022] The present invention also provides a bilayer core-shell nanoparticle composite thermosensitive gel, comprising the above-mentioned bilayer core-shell nanoparticles and a thermosensitive gel material; wherein the thermosensitive gel material is a PLGA-PEG-PLGA triblock copolymer.

[0023] The present invention also provides a method for preparing the above-mentioned bilayer core-shell nanoparticle composite thermosensitive gel, wherein the aqueous dispersion of the above-mentioned bilayer core-shell nanoparticles is mixed uniformly with PLGA-PEG-PLGA thermosensitive gel material at low temperature to obtain the bilayer core-shell nanoparticle composite thermosensitive gel.

[0024] The present invention also provides the use of the bilayer core-shell nanoparticles as described above or the above-described bilayer core-shell nanoparticle composite thermosensitive gel in the preparation of drugs for postoperative analgesia and / or anti-inflammatory purposes.

[0025] As a further aspect of the present invention: the bilayer core-shell nanoparticles or bilayer core-shell nanoparticle composite thermosensitive gel exhibited the following properties in an in vitro release test: Within 24 hours, the cumulative release rate of bupivacaine is ≥40%, and the cumulative release rate of magnesium is 10-20%. Within 48 hours, the cumulative release rate of bupivacaine was ≥60%, and the cumulative release rate of magnesium was 20-30%. Within 72 hours, the cumulative release rate of bupivacaine is 70-80%, and the cumulative release rate of magnesium is 30-40%. Within 7 days, the cumulative release rate of bupivacaine was ≥85%, and the cumulative release rate of magnesium was ≥60%. Within 14 days, the cumulative release rate of bupivacaine was ≥95%, and the cumulative release rate of magnesium was ≥85%.

[0026] Example 1: Preparation of bilayer core-shell nanoparticles and their composite thermosensitive gel Preparation of magnesium agent@PLGA core: PLGA was dissolved in dichloromethane as the oil phase; Magnesium sulfate is dissolved in water to form the internal aqueous phase; The aqueous phase is added to the oil phase and ultrasonically emulsified to form a primary emulsion; The colostrum is rapidly injected into the external aqueous phase containing PVA, and high-speed shear emulsification is used to form a secondary emulsion; The organic solvent was evaporated by magnetic stirring overnight. The precipitate was collected by high-speed centrifugation, washed, and magnesium agent@PLGA nanoparticles were obtained. The optimal magnesium dosage is 20 mg / mL.

[0027] Bupivacaine encapsulated in a lipid shell: DSPC, cholesterol, DSPE-PEG (molar ratio 60:35:5) and bupivacaine were dissolved together in chloroform, placed in a round-bottom flask, and the chloroform was removed by rotary evaporation to form a uniform lipid film. Add magnesium-containing PLGA nanoparticles to PBS buffer and hydrate at 60°C for 1 hour to allow the lipid film to hydrate and detach, self-assemble into a lipid bilayer, and simultaneously encapsulate bupivacaine and the PLGA core. The optimal dosage of bupivacaine was 10 mg / mL. Uniform core-shell nanoparticles with uniform particle size were obtained by extrusion through a membrane.

[0028] Preparation of composite thermosensitive gel: The PLGA-PEG-PLGA triblock copolymer was dispersed in deionized water at 4°C using a cold dissolution method and allowed to swell overnight to form a clear blank thermosensitive gel solution. The concentrated solution of bilayer core-shell nanoparticles and the blank thermosensitive gel solution were mixed evenly at 4°C in a certain proportion to obtain the bilayer core-shell nanoparticle composite thermosensitive gel.

[0029] Example 2: Study on in vitro release behavior The bilayer core-shell nanoparticle composite thermosensitive gel prepared in Example 1 was placed in a dialysis bag and immersed in release medium (PBS, pH 7.4). An in vitro release experiment was conducted under isothermal shaking conditions at 37°C. Samples were taken at predetermined time points (24h, 48h, 72h, 7d, 14d), and an equal volume of fresh medium was added simultaneously at the same temperature. The concentration of bupivacaine in the release medium was determined by high-performance liquid chromatography (HPLC), and the concentration of magnesium ions was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The cumulative release rate was calculated.

[0030] The results are shown in Table 1. The composite thermosensitive gel of the present invention can achieve the designed target release curve. Bupivacaine is rapidly released within 48 hours to meet the needs of acute analgesia, while magnesium ions are released continuously and slowly, exerting long-term anti-inflammatory and repair effects, which perfectly matches the pathophysiological process of postoperative pain management.

[0031] Table 1. In vitro cumulative release rate of the bilayer core-shell nanoparticle composite thermosensitive gel Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bilayer core-shell nanoparticle, characterized in that, The nanoparticles include: The core is a PLGA nanoparticle loaded with magnesium. The outer shell is a lipid bilayer loaded with bupivacaine, which wraps around the outer surface of the core.

2. The bilayer core-shell nanoparticles according to claim 1, characterized in that, The magnesium agent is magnesium sulfate; The lipid bilayer is composed of DSPC, cholesterol, and DSPE-PEG.

3. The bilayer core-shell nanoparticles according to claim 2, characterized in that, The molar ratio of DSPC, cholesterol, and DSPE-PEG is 60:35:

5.

4. A method for preparing the bilayer core-shell nanoparticles according to any one of claims 1 to 3, characterized in that, Includes the following steps: Step 1: Prepare PLGA nanoparticle cores loaded with magnesium agent using the double emulsion-solvent evaporation method; Step 2: Using the thin film hydration method, bupivacaine and lipid materials are made into a lipid film, and then an aqueous solution of the PLGA nanoparticle core prepared in Step 1 is added for hydration. The lipid bilayer loaded with bupivacaine is self-assembled and encapsulates the PLGA core to obtain bilayer core-shell nanoparticles.

5. The preparation method according to claim 4, characterized in that, In step 1, the dosage of magnesium is 10-30 mg / mL PLGA solution; In step 2, the dosage of bupivacaine is 5-15 mg / mL.

6. A bilayer core-shell nanoparticle composite thermosensitive gel, characterized in that, Includes the bilayer core-shell nanoparticles and thermosensitive gel materials as described in any one of claims 1 to 3.

7. The bilayer core-shell nanoparticle composite thermosensitive gel according to claim 6, characterized in that, The thermosensitive gel material is a PLGA-PEG-PLGA triblock copolymer.

8. A method for preparing the bilayer core-shell nanoparticle composite thermosensitive gel according to claim 5 or 6, characterized in that, The aqueous dispersion of the bilayer core-shell nanoparticles according to any one of claims 1 to 3 is mixed with PLGA-PEG-PLGA thermosensitive gel material at low temperature to obtain a bilayer core-shell nanoparticle composite thermosensitive gel.

9. The use of a bilayer core-shell nanoparticle as described in any one of claims 1 to 3, or a bilayer core-shell nanoparticle composite thermosensitive gel as described in claim 5 or 6, in the preparation of a postoperative analgesic and / or anti-inflammatory drug.

10. The application according to claim 9, characterized in that, In in vitro release tests, the bilayer core-shell nanoparticles or bilayer core-shell nanoparticle composite thermosensitive gel showed that bupivacaine was rapidly released within 48 hours, while magnesium was continuously released over 7 to 14 days.

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