Gel composition containing dual-phase microsphere and biodegradable high polymer material and use thereof

Abstract

A gel composition containing a dual-phase microsphere and a biodegradable high polymer material and a use thereof. The gel composition comprises a dual-phase microsphere, a biodegradable high polymer material and an auxiliary material. The dual-phase microsphere is a polylactic acid / inorganic material dual-phase microsphere. Compared with a single-phase microsphere, the gel composition containing the dual-phase microsphere and the biodegradable high polymer material has the advantages of no displacement, good viscosity, high pressure resistance, thermal degradation resistance, and enzymolysis resistance by means of the interaction of the dual-phase microsphere and the high polymer material, integrates the advantages of the three materials, and can be used for filling, repairing and shaping biological tissues.

Description

A gel composition containing dual-phase microspheres and biodegradable polymer material and its application Technical Field

[0001] The present invention relates to the technical field of biomedical materials, in particular to a gel composition containing dual-phase microspheres and biodegradable polymer materials and application thereof. Background Art

[0002] Hyaluronic acid (HA) is widely present in many body tissues, including synovial joint fluid, vitreous humor in the eye, cartilage, blood vessels, extracellular matrix, skin, and the umbilical cord. HA has strong water absorption and water retention properties, forming a highly viscoelastic substance in aqueous solutions. Furthermore, its non-immunogenic and non-toxic properties allow it to be incorporated into tissues and has diverse applications in the cosmetic, biomedical, pharmaceutical, and food industries. Hydroxyapatite (HAP) exhibits excellent biocompatibility and osteoconductivity and is a major inorganic component of human and animal bones and teeth. It can tightly bind to both soft and hard tissues within a short period of time, releasing harmless ions that participate in human metabolism, stimulate or induce bone proliferation, and promote the repair of defective tissue. It has been widely used in human bone tissue repair. Polylactic acid (PLA), also known as polylactide, is a polyester polymer derived from the polymerization of lactic acid. Due to its excellent biocompatibility, biodegradability, and ease of processing, it is used in conjunction with HAP to enhance its mechanical and biological properties.

[0003] Patent document CN110636870A discloses a dermal filler composition comprising HA and HAP, wherein the HA and HAP are chemically bonded. This dermal filler composition can be used to correct wrinkles and nasolabial folds, thereby restoring a smooth facial appearance. Patent document CN102380128B discloses a composite scaffold material comprising HAP, sodium hyaluronate (SH), and konjac glucomannan (KGM). This composite scaffold material has a uniquely structured HAP deposited layer that improves the mechanical properties of the scaffold material. The introduction of SH promotes cell growth and reproduction, meeting the requirements of bone tissue engineering scaffolds.

[0004] Currently, there have been reports of HAP and PLA binary composites, as well as HAP and PLA and other polymer ternary composites or composite microspheres, both domestically and internationally. Dong Yan et al. (Additive Manufacturing, 2020; 34: 101305) have produced PLA and nanoscale HAP blended microspheres with a minimum particle size of approximately 100 μm, primarily for use in microcarrier research. Patents such as a hydroxyapatite-loaded polylactic acid porous microsphere and preparation method (CN103768658B) and a polylactic acid / hydroxyapatite whisker composite porous scaffold for bone tissue and preparation method (CN105797215A) are primarily used for bone defect repair, filling, and drug loading, but have not been applied to tissue filling. Furthermore, conventional physical mixing of biphasic microspheres with biodegradable polymer materials can lead to problems such as displacement, poor viscosity, and a sudden drop in modulus after sterilization, resulting in easy sedimentation, uneven dispersion, and poor cohesion. The above patent document does not disclose the preparation of biphasic microspheres by compounding HAP and PLA and then cross-linking the microspheres with a polymer material (such as HA) to form a three-phase stable composite gel for filling and repairing biological tissues.

[0005] Summary of the Invention

[0006] The present invention overcomes the defects in the prior art and provides a gel composition containing dual-phase microspheres and biodegradable polymer materials and application thereof.

[0007] The first aspect of the present invention provides a gel composition containing biphasic microspheres and a biodegradable polymer material. The gel composition includes biphasic microspheres, a biodegradable polymer material and auxiliary materials. The biphasic microspheres are polylactic acid / inorganic material biphasic microspheres. The biphasic microspheres and the biodegradable polymer material are cross-linked, and the cross-linking includes physical cross-linking or chemical cross-linking.

[0008] The auxiliary materials include local anesthetic, hydrochloric acid solution, and sodium chloride solution or phosphate buffer solution.

[0009] The auxiliary material can be added to the biodegradable polymer material before the dual-phase microspheres and the biodegradable polymer material are cross-linked, or added after the two are cross-linked.

[0010] Preferably, the osmotic pressure of the phosphate buffer solution or sodium chloride solution is 200 to 400 mOsm / L, more preferably 220 to 380 mOsm / L, particularly preferably 250 to 350 mOsm / L;

[0011] The local anesthetic is selected from one of amide type and ester type or a combination thereof.

[0012] Furthermore, the concentration of the local anesthetic in the composition is 1 to 5 mg / mL.

[0013] Furthermore, the content of biphasic microspheres in the gel composition is 5-35wt% (such as 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, 25wt%), preferably 10-25wt%.

[0014] Furthermore, the dual-phase microspheres are polylactic acid / inorganic material dual-phase microspheres.

[0015] Furthermore, the average particle size of the biphasic microspheres is 10 to 80 μm (such as 10 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 46 μm, 47 μm, 48 μm, 49 μm, 50 μm, 55 μm, 60 μm), preferably, 15 to 55 μm, and particularly preferably, 20 to 50 μm.

[0016] Furthermore, the inorganic material is selected from one or a combination of two or more of calcium carbonate, calcium phosphate and calcium tartrate; further, the calcium phosphate is preferably calcium hydroxyapatite; further, the inorganic material is a nano-inorganic material.

[0017] In one embodiment of the present invention, the inorganic material is nano-calcium hydroxyapatite (HAP).

[0018] Furthermore, the content of the inorganic material in the dual-phase microspheres is 5% to 15% (e.g., 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%), preferably 6% to 15%, and particularly preferably 6% to 12% (based on the entire microspheres).

[0019] Furthermore, the concentration of the biodegradable polymer material in the gel composition is 10-40 mg / mL.

[0020] Furthermore, the biodegradable polymer material is selected from one or a combination of two or more of hyaluronic acid or its salts, cellulose, collagen, chitosan and gelatin, preferably hyaluronic acid or its salts, wherein the hyaluronate is selected from any one of sodium hyaluronate, potassium hyaluronate, calcium hyaluronate, magnesium hyaluronate, ammonium hyaluronate, tetrabutylammonium hyaluronate, bismuth hyaluronate and zinc hyaluronate, preferably sodium hyaluronate.

[0021] Furthermore, the hyaluronic acid or its salt is cross-linked hyaluronic acid or its salt and / or non-cross-linked hyaluronic acid or its salt.

[0022] The molecular weight of hyaluronic acid can be arbitrary, such as 100 KDa to 3000 KDa.

[0023] Furthermore, the cross-linked hyaluronic acid is prepared by a cross-linking agent, and the cross-linking agent is selected from one or a combination of two or more of dialdehydes, disulfides, polyethylene glycol (PEG) cross-linkers, divinyl sulfone, diglycidyl ether, diepoxides, diamines and polyamines.

[0024] Furthermore, the cross-linking agent is selected from biscarbodiimide, fatty diamine, ethylenediamine, hexamethylenediamine, endogenous polyamine (spermine or spermidine), pentaerythritol tetraglycidyl ether (PETGE), divinyl sulfone (DVS), 1,4-butanediol diglycidyl ether (BDDE), 1,2-bis(2,3-epoxypropoxy)ethylene (EGDGE), 1,2,7,8-diepoxyoctane (DEO), (phenylene bis-(ethyl)-carbodiimide and 1,6-hexamethylene bis(ethylcarbodiimide), adipic acid dihydrazide (ADH), bis(sulfosuccinimide) octanediamide, The cross-linking agent may be selected from the group consisting of bis(2,3-epoxypropyl)-2,3-epoxycyclohexane, bis(2,3-epoxypropyl)-butane, 1,4-bis(2,3-epoxypropyl)-2,3-epoxycyclohexane, 1,3-butadiene diepoxide, 1,2,7,8-diepoxyoctane, 1,5-hexadiene diepoxide, and glutaraldehyde. Preferably, the cross-linking agent is 1,4-butanediol diglycidyl ether (BDDE) or an endogenous polyamine (spermine or spermidine).

[0025] In one embodiment of the present invention, the hyaluronic acid or its salt is cross-linked hyaluronic acid or its salt.

[0026] In one embodiment of the present invention, the hyaluronic acid or its salt is non-cross-linked hyaluronic acid or its salt.

[0027] In one embodiment of the present invention, the hyaluronic acid or its salt is cross-linked sodium hyaluronate.

[0028] Furthermore, the cross-linking degree of the cross-linked sodium hyaluronate is 0.5% to 5% (such as 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%), preferably, 1% to 5%, and particularly preferably, 1% to 4%.

[0029] Furthermore, the concentration of the cross-linked sodium hyaluronate is 10-40 mg / mL.

[0030] In one embodiment of the present invention, the concentration of cross-linked sodium hyaluronate is 17 mg / mL.

[0031] Furthermore, the osmotic pressure of the phosphate buffer solution or the sodium chloride solution is 200 to 400 mOsm / L (e.g., 200 mOsm / L, 210 mOsm / L, 220 mOsm / L, 230 mOsm / L, 240 mOsm / L, 250 mOsm / L, 260 mOsm / L, 270 mOsm / L, 280 mOsm / L, 290 mOsm / L, 300 mOsm / L, sm / L, 310mOsm / L, 320mOsm / L, 330mOsm / L, 340mOsm / L, 350mOsm / L, 360mOsm / L, 370mOsm / L, 380mOsm / L, 390mOsm / L, 400mOsm / L), preferably, 220-380mOsm / L, particularly preferably, 250-350mOsm / L.

[0032] Furthermore, the pH of the phosphate buffer solution or the sodium chloride solution is 5 to 8 (such as 5, 5.5, 6, 6.5, 7, 7.5, 8), preferably 5.5 to 8, and particularly preferably 6.5 to 7.5.

[0033] Further, the local anesthetic is selected from the group consisting of lidocaine or its salt, bupivacaine or its salt, butancaine or its salt, caticaine or its salt, cinchocaine or its salt, chlorocaine or its salt, ethyl p-piperidylacetylaminobenzoate or its salt, etidocaine or its salt, mepivacaine or its salt, oxethacaine or its salt, prilocaine or its salt, ropivacaine or its salt, tolicaine or its salt, trimecaine or its salt, vardocaine or its salt, articaine or its salt, levobupivacaine or its salt, amicaine or its salt, cocaine or its salt, The group consisting of one or more of propancaine or its salt, chloroparacaine or its salt, cyclomethicaine or its salt, proparacaine or its salt, tetracaine or its salt, benzocaine or its salt, butacaine or its salt, butyrocaine or its salt, butylaminobenzoate or its salt, chloroprocaine or its salt, dimethocaine or its salt, oxybuprocaine or its salt, piperocaine or its salt, p-ethoxycaine or its salt, procaine or its salt, propoxycaine or its salt, and tricaine or its salt, preferably lidocaine or its salt, more preferably lidocaine hydrochloride.

[0034] The dual-phase microspheres and the biodegradable polymer material in the composition are cross-linked.

[0035] Furthermore, the crosslinking includes any one of physical crosslinking and chemical crosslinking.

[0036] Furthermore, the cross-linking includes cross-linking of polylactic acid and biodegradable polymer materials in the dual-phase microspheres.

[0037] In one embodiment of the present invention, the cross-linking comprises cross-linking polylactic acid and hyaluronic acid or a salt thereof in the biphasic microspheres.

[0038] Furthermore, the crosslinking of the polylactic acid and the biodegradable polymer material includes any one of physical crosslinking and chemical crosslinking.

[0039] The physical crosslinking comprises modifying the surface charge of the biphasic microspheres and then forming an electrostatic crosslink with a biodegradable polymer material. Furthermore, the physical crosslinking comprises modifying the surface charge of the biphasic microspheres and then forming an electrostatic crosslink with a biodegradable polymer material having positive ions. Furthermore, modifying the surface charge of the biphasic microspheres comprises immersing the biphasic microspheres in an alkaline buffer solution to separate them.

[0040] The chemical cross-linking comprises modifying the biphasic microspheres with amino groups and then performing a chemical cross-linking reaction with a biodegradable polymer material; preferably, the amino modification comprises reacting the biphasic microspheres with an amine compound.

[0041] In one embodiment of the present invention, the biphasic microspheres are polylactic acid / nano-calcium hydroxyapatite biphasic microspheres. In one embodiment of the present invention, the content of nano-calcium hydroxyapatite in the biphasic microspheres is 10% (based on the entire microspheres).

[0042] In one embodiment of the present invention, in the polylactic acid / nano-calcium hydroxyapatite dual-phase microspheres, the rest of the microspheres except hydroxyapatite are polylactic acid.

[0043] In one embodiment of the present invention, a gel composition comprising biphasic microspheres and a biodegradable polymer material is provided. The composition comprises polylactic acid / nano-calcium hydroxyapatite biphasic microspheres and a cross-linked sodium hyaluronate gel. The cross-linked sodium hyaluronate gel is prepared by cross-linking sodium hyaluronate and then reacting it with lidocaine hydrochloride, hydrochloric acid, and a phosphate buffer solution. The polylactic acid / nano-calcium hydroxyapatite biphasic microspheres and the cross-linked sodium hyaluronate are physically cross-linked to form the composition.

[0044] The second aspect of the present invention provides a method for preparing the gel composition containing the dual-phase microspheres and the biodegradable polymer material as described in the first aspect.

[0045] The preparation method comprises cross-linking the biphasic microspheres and the biodegradable polymer material to form a gel composition,

[0046] Furthermore, the crosslinking includes physical crosslinking or chemical crosslinking.

[0047] The physical crosslinking includes modifying the surface charge of the biphasic microspheres to obtain modified biphasic microspheres carrying negative ions on the surface, and mixing the modified biphasic microspheres with cross-linked hyaluronic acid or its salt having positive ions to produce electrostatic crosslinking; further, the cross-linked hyaluronic acid or its salt having positive ions is a cross-linked hyaluronic acid or its salt obtained by cross-linking with BDDE or polyamine; further, the surface charge modification of the biphasic microspheres includes immersing the biphasic microspheres in an alkaline buffer solution and separating them.

[0048] The specific steps of the physical cross-linking include:

[0049] Step 1: preparing biodegradable polymer materials;

[0050] Step 2: Preparation of biphasic microspheres;

[0051] Step 3: Physically cross-linking the dual-phase microspheres of step 2 and the biodegradable polymer material of step 1.

[0052] Furthermore, step 1 includes: dissolving the biodegradable polymer material in a solvent, adding auxiliary materials, and swelling.

[0053] Furthermore, step 2 includes:

[0054] 2-1) dissolving polylactic acid (PLA) in dichloromethane to prepare a solution, and filtering;

[0055] 2-2) adding an inorganic material and performing ultrasonication and stirring to completely disperse the inorganic material in the solution to form a uniformly dispersed suspension;

[0056] 2-3) preparing a polyvinyl alcohol solution, and adding the suspension obtained in 2-2) dropwise to the PVA solution to form microspheres under stirring, shearing and emulsification;

[0057] 2-4) The emulsified solution is stirred to evaporate the dichloromethane, and then the obtained intermediate product is washed and filtered.

[0058] In step 2-1), preferably, the concentration of the PLA dichloromethane solution is 10 mg / mL to 80 mg / mL, including but not limited to: 15 mg / mL, 30 mg / mL, 40 mg / mL, 60 mg / mL and 80 mg / mL.

[0059] Preferably, the PLA comprises a mixture of one or more of poly (L-lactic acid) (PLLA), poly (D-lactic acid) (PDLLA) and poly (D-lactic acid) (PDLA).

[0060] Preferably, the molecular weight of the PLA is in the range of 10 KDa to 150 KDa.

[0061] In a specific embodiment, in the step (2-2), preferably, the inorganic material is hydroxyapatite with a mass fraction of 5% to 15% to ensure that it can be completely incorporated into the polylactic acid microspheres.

[0062] Preferably, the ultrasonic energy is 1-300 kJ, preferably 1-20 kJ, and the ultrasonic energy calculation formula is as follows:

[0063] Ultrasonic energy (KJ) = ultrasonic power (W) × ultrasonic time (s) / 1000.

[0064] In a specific embodiment, in step 2-3), preferably, the concentration of the polyvinyl alcohol solution is 5 mg / ml to 30 mg / ml. In this concentration range, the emulsification effect can be ensured and the size of the microspheres can be controlled.

[0065] Preferably, the ratio of the dichloromethane solution to the polyvinyl alcohol solution is 1 / 2-1 / 10.

[0066] Preferably, the rotation speed of the stirring paddle in the stirring device is 100-600 rpm / min. In this rotation speed range, continuous emulsification can be ensured to form a good emulsion.

[0067] In a specific embodiment, in step 2-4), preferably, the water bath temperature is 20-37°C. In this temperature range, the volatilization rate of dichloromethane can be controlled, thereby optimizing the hollow effect and surface microporous structure of the microspheres; after step 2-4), the obtained filter cake is dried to obtain dual-phase polylactic acid hydroxyapatite nanodispersed microspheres; preferably, the drying process includes vacuum drying and freeze drying. Vacuum drying utilizes the principle of ice crystal sublimation to avoid the destruction of the internal structure of the microspheres by the liquefaction process of the solid phase component, and can better maintain the spatial structure of the prepared polylactic acid microspheres.

[0068] Furthermore, step 3 includes:

[0069] 3-1) modifying the surface charge of the biphasic microspheres obtained in step 2 to obtain modified biphasic microspheres carrying negative ions on the surface;

[0070] 3-2) mixing the obtained modified dual-phase microspheres with the polymer material obtained in step 1, and subjecting them to electrostatic crosslinking to obtain the composition;

[0071] Preferably, the surface charge modification of the biphasic microspheres comprises separating the biphasic microspheres by immersing them in an alkaline buffer solution; more preferably, the alkaline buffer solution is a PBS solution (phosphate buffer solution), and the pH range is preferably 9.0 to 11.0.

[0072] In one embodiment, the microspheres are biphasic polylactic acid hydroxyapatite dispersed microspheres, and the physical crosslinking includes immersing the biphasic polylactic acid hydroxyapatite dispersed microspheres in a PBS solution with a pH of 9.0 to 11.0 to perform surface charge modification so that the surface of the microspheres carries a negative charge, separating and removing the biphasic microspheres, and physically mixing them with a cross-linked hyaluronic acid gel so that the carboxylate negative ions on the surface of the polylactic acid and the ammonium positive ions in the cross-linked hyaluronic acid undergo electrostatic crosslinking.

[0073] The chemical crosslinking includes amino-modifying the biphasic microspheres and then performing a chemical crosslinking reaction with a biodegradable polymer material; further, the amino modification includes reacting the biphasic microspheres with an amine compound; further, the crosslinking reaction includes coupling the modified biphasic microspheres with hyaluronic acid or a salt thereof in the presence of a carbodiimide activator.

[0074] Specifically, chemical crosslinking includes the following steps:

[0075] Step 1': preparing a biodegradable polymer material;

[0076] Step 2': Preparation of biphasic microspheres (same as physical crosslinking step 2);

[0077] Step 3': chemically cross-linking the dual-phase microspheres obtained in step 2' and the biodegradable polymer material obtained in step 1', and adding auxiliary materials after the reaction to obtain the composition.

[0078] Furthermore, step 1′ includes dissolving a biodegradable polymer material in a solvent;

[0079] Further, step 2' is the same as step 2 of the physical cross-linking process;

[0080] Furthermore, step 3' comprises: 3'-1) performing amino modification on the polylactic acid in the biphasic microspheres prepared in step 2';

[0081] 3'-2) chemically cross-linking the modified biphasic microspheres with the biodegradable polymer material of step 1' to obtain the composition; preferably, the biodegradable polymer material is hyaluronic acid or a salt thereof.

[0082] Furthermore, the amino modification described in 3'-1) comprises reacting the biphasic microspheres with an amine compound;

[0083] 3'-2) The cross-linking reaction comprises coupling the modified biphasic microspheres with hyaluronic acid or its salt in the presence of a carbodiimide activator.

[0084] In one embodiment, the amine compound comprises a diamine, a polyamine, or a polyamino compound.

[0085] Preferably, the diamine includes any one of aliphatic diamines, aromatic diamines and heteroatom diamines; for example, but not limited to, fatty diamines, ethylenediamine, hexamethylenediamine; the polyamine includes any one of aliphatic polyamines, aromatic polyamines and heteroatom polyamines; for example, but not limited to, endogenous polyamines such as spermidine and spermine; the polyamino compound includes any one of double-terminated amino polyethylene glycol and terminally amino multi-arm polyethylene glycol.

[0086] Furthermore, the carbodiimide activator includes one or more of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide, 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide, 1,3-bis[di(methoxymethyl)methyl]carbodiimide or their salts.

[0087] In one embodiment, the preparation method further comprises using an auxiliary agent together with the carbodiimide activator; for example, N-hydroxysuccinimide (NHS), tert-butyl alcohol, etc. The water-soluble carbodiimide activator needs to be used in combination with the auxiliary agent to improve the efficiency of the crosslinking reaction. The amount of the auxiliary agent added is 10-30% of the mass of the carbodiimide.

[0088] The amount of the amine compound added to the reaction system is 30-200% of the mass of the biphasic microspheres; the concentration range of the amine compound is 10-1000 mg / mL.

[0089] Furthermore, the added amount of the carbodiimide activator is 10 to 150% of the total mass of the hyaluronic acid or its salt.

[0090] Furthermore, the concentration of the hyaluronic acid or its salt solution is 10 to 40 mg / mL.

[0091] Furthermore, the temperature of the amino modification reaction and the cross-linking reaction is 5 to 60° C., the reaction time is 6 to 24 hours, and the pH value of the reaction system is in the range of 5.0 to 6.0.

[0092] In one embodiment, the microspheres are biphasic polylactic acid / hydroxyapatite microspheres. The chemical crosslinking comprises dispersing the biphasic polylactic acid / hydroxyapatite microspheres in water, adding an amine compound (polyamine derivative), adjusting the pH, causing the carboxyl groups on the microsphere surface to react with the polyamine derivative to modify the surface with amino groups; then, adding the amino-modified polylactic acid hydroxyapatite biphasic microspheres (PLA-HAP biphasic microspheres) to a hyaluronic acid or salt solution, adjusting the pH to 5.0-6.0, and simultaneously adding a carbodiimide activator and an auxiliary agent to complete the coupling reaction between the PLA-HAP biphasic microspheres and HA. The surface amino modification reaction temperature is 5-60°C, and the reaction time is 6-24 hours; the coupling reaction temperature is 5-60°C, and the reaction time is 6-24 hours.

[0093] The third aspect of the present invention provides a use of the gel composition containing biphasic microspheres and a biodegradable polymer material as described in the first aspect, or the gel composition obtained by the preparation method described in the second aspect, in the preparation of a drug carrier, tissue filler or tissue repair material.

[0094] Furthermore, the drug carrier can be a drug carrier of a biological drug, a chemical drug or a naturally extracted drug.

[0095] Beneficial effects of the present invention:

[0096] The gel composition containing dual-phase microspheres and biodegradable polymer materials of the present invention is optimized by adjusting the composition and ratio of the dual-phase microspheres and the biodegradable polymer materials, optimizing the proportion of inorganic materials in the dual-phase microspheres, and optimizing process parameters such as the particle size of the microspheres. The resulting composition has the advantages of being non-displaceable, having good viscosity, strong pressure resistance, and resistance to sterilization (resistance to thermal degradation), making it particularly suitable for soft tissue filling and shaping.

[0097] The present invention first prepares polylactic acid-inorganic material biphasic microspheres, and then physically or chemically crosslinks the carboxyl groups at the ends of the polylactic acid in the biphasic microspheres with hyaluronic acid to form a three-phase composite gel with high stability and good biocompatibility, which can be used for filling and repairing biological tissues. The biphasic microspheres in the present invention further improve the hydrophilicity of the polylactic acid microspheres due to the addition of a hydrophilic calcium salt inorganic material (such as hydroxyapatite). Moreover, the calcium-based inorganic material in the two-phase microspheres can be introduced into the macroscopic network structure of cross-linked hyaluronic acid using micron-sized polylactic acid as a carrier (the particles of the cross-linked hyaluronic acid are also micron-sized). Through the complexation between calcium ions and the carboxyl and hydroxyl groups in the hyaluronic acid, the network gaps between the cross-linked hyaluronic acids are filled, so that the three-phase gel has a tighter network structure. At the same time, with the help of the complexation between the calcium-based inorganic material and the hyaluronic acid, the distance between the polylactic acid and hyaluronic acid molecular chains is shortened, thereby improving the cross-linking reaction efficiency of the two and improving the mechanical strength and thermal stability of the three-phase composite gel. The gel composition of the present invention can exert the instant filling effect of hyaluronic acid, the collagen regeneration effect of polylactic acid, and the bone filling and lactic acid neutralization effect of calcium-based inorganic materials such as hydroxyapatite, integrating the advantages of the three materials into one. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] Figure 1 is an electron microscope and SEM image of the microspheres (Figure A is an electron microscope image of the sample in Example 4, Figure B is an SEM image of the dual-phase microspheres in Example 4, and Figure C is an SEM image of the PLA microspheres in Comparative Example 1).

[0099] Figure 2 shows photos of samples before and after the compressive performance test (the left photo is a photo of the sample before the test, and the right photo is a photo of the sample after the test).

[0100] FIG3 is a diagram showing the results of the compression test (wherein, from left to right are Example 6, Comparative Example 1, Example 7, Example 11, Example 9, Example 12, Comparative Example 2, Example 8, and Example 10).

[0101] FIG4 is a graph showing viscosity test results (wherein, from left to right are Comparative Example 2, Comparative Example 1, Example 12, Example 11, Example 10, Example 9, Example 8, Example 7 and Example 6).

[0102] Figure 5 is a diagram of the fluidity test results (wherein, Figure A shows from left to right: Example 10, Example 6, Example 7, Comparative Example 2, Example 8, Example 11 and Example 12; Figure B shows from the left side Example 9 and from the right side Comparative Example 1). DETAILED DESCRIPTION

[0103] In order to more clearly understand the technical content of the present invention, the following embodiments are given in detail, the purpose of which is only to better understand the content of the present invention but not to limit the scope of protection of the present invention.

[0104] The polymer raw materials, inorganic materials, reagents, etc. used in the present invention are all commercially available products.

[0105] Example 1 Preparation of cross-linked sodium hyaluronate gel

[0106] 0.4 g of sodium hyaluronate (molecular weight 500 KDa) was dissolved in 2 ml of water for injection, 0.2 ml of 20% sodium hydroxide solution was added, 8 μl of 1,4-butanediol diglycidyl ether was added, and after the cross-linking reaction, 4 ml of 2.6 mol / L hydrochloric acid was added to adjust the pH to 6.5-7.5, and then 7 ml of 1% lidocaine hydrochloride was added, followed by 5 ml of PBS buffer and 5.31 ml of water for injection to obtain a sodium hyaluronate gel in which the concentration of sodium hyaluronate was 17 mg / mL.

[0107] Example 2 Preparation of cross-linked sodium hyaluronate gel

[0108] 0.4 g of sodium hyaluronate (molecular weight 500 KDa) was dissolved in 2 ml of water for injection, 0.2 ml of 20% sodium hydroxide solution was added, 4 μl of 1,4-butanediol diglycidyl ether was added, and after the cross-linking reaction, 4 ml of 2.6 mol / L hydrochloric acid was added to adjust the pH to 6.5-7.5, and then 7 ml of 1% lidocaine hydrochloride was added, followed by 5 ml of PBS buffer and 5.31 ml of water for injection to obtain a sodium hyaluronate gel in which the concentration of sodium hyaluronate was 17 mg / mL.

[0109] Example 3 Preparation of cross-linked sodium hyaluronate gel

[0110] 0.4 g of sodium hyaluronate (molecular weight 500 KDa) was dissolved in 2 ml of water for injection, 0.2 ml of 20% sodium hydroxide solution was added, 12 μl of 1,4-butanediol diglycidyl ether was added, and after the cross-linking reaction, 4 ml of 2.6 mol / L hydrochloric acid was added to adjust the pH to 6.5-7.5, and then 7 ml of 1% lidocaine hydrochloride was added, followed by 5 ml of PBS buffer and 5.31 ml of water for injection to obtain a sodium hyaluronate gel in which the concentration of sodium hyaluronate was 17 mg / mL.

[0111] Example 4 Preparation of biphasic microspheres

[0112] The polylactic acid (molecular weight 100KDa) that takes by weighing 1.8g is positioned in the 50mL beaker, the methylene dichloride that adds 50mL then, stirring with a medicine spoon makes it dissolve fully, then filters in the ultrasonic special beaker with 10mm nylon 66 material syringe filter, then takes the nano hydroxyapatite of 0.2g and joins in this system, 60% power effect 10min fully disperses nano material in the methylene dichloride solution of polylactic acid, during this period the polyvinyl alcohol solution (1.5wt%) of 135mL is joined in the 300mL three-necked flask and is positioned in 30 ℃ of water-baths, is mechanically stirred at 400r / min with speed subsequently. Treat that ultrasonic end subsequently the methylene dichloride turbid liquid is slowly joined in the polyvinyl alcohol solution, stir and volatilize and remove methylene dichloride overnight.

[0113] The suspension obtained in the previous step was diluted to 500 mL with purified water, and then allowed to stand for 1 hour. The upper suspension was poured off and repeated twice. The precipitate was redissolved and filtered with a 0.45 μm water filter membrane to remove the liquid. The obtained solid was then dispersed with 200 mL of purified water and filtered again. This was repeated four times. The obtained solid was then redissolved with 150 mL of purified water and added to a Schott bottle. The product was placed in a 100°C oven and heated for 30 minutes. The product was taken out and cooled and filtered. The product was washed three times with purified water. The solid obtained from the last wash was transferred to a culture dish and dried in a vacuum drying oven at 40°C overnight to obtain the final product, biphasic microspheres, with a particle size mainly distributed between 20 and 50 μm.

[0114] Example 5 Preparation of biphasic microspheres

[0115] The polylactic acid (molecular weight 100KDa) that takes by weighing 1.8g is positioned in the 50mL beaker, the methylene dichloride that adds 50mL then, stirring with a medicine spoon makes it dissolve fully, then filters into the ultrasonic special beaker with 10mm nylon 66 material syringe filter, then takes the nano hydroxyapatite of 0.115g and joins in this system, 60% power effect 10min fully disperses nano material in the methylene dichloride solution of polylactic acid, during this period the polyvinyl alcohol solution (1.5wt%) of 135mL is joined in the 300mL three-necked flask and is positioned in 30 ℃ of water-baths, is the mechanical stirring of 400r / min with speed subsequently.Treat that ultrasonic finishes and the methylene dichloride turbid liquid is slowly joined in the polyvinyl alcohol solution subsequently, stirs and volatilizes and removes methylene dichloride overnight.

[0116] The suspension obtained in the previous step was diluted to 500 mL with purified water, and then allowed to stand for 1 hour. The upper suspension was poured off and repeated twice. The precipitate was redissolved and filtered with a 0.45 μm water filter membrane to remove the liquid. The obtained solid was then dispersed with 200 mL of purified water and filtered again. This was repeated four times. The obtained solid was then redissolved with 150 mL of purified water and added to a Schott bottle. The product was placed in a 100°C oven and heated for 30 minutes. The product was taken out and cooled and filtered. The product was washed three times with purified water. The solid obtained from the last wash was transferred to a culture dish and dried in a vacuum drying oven at 40°C overnight to obtain the final product, biphasic microspheres, with a particle size mainly distributed between 20 and 50 μm.

[0117] Example 6 Physical crosslinking of three-phase gel

[0118] 0.9 g of the biphasic microspheres from Example 4 were soaked in 50 mL of a pH 9.0 PBS solution for surface charge modification, resulting in a negative charge on the microsphere surface. After soaking for 30 minutes, the biphasic microspheres were separated and removed, drained, and physically mixed with 17.1 g of the cross-linked hyaluronic acid gel from Example 1. This allowed the carboxylate anions on the polylactic acid surface to electrostatically crosslink with the ammonium cations in the cross-linked hyaluronic acid, and also allowed the calcium on the surface of the biphasic microspheres to form coordination bonds with the carboxylates of the cross-linked sodium hyaluronate gel. After uniform mixing, the three-phase gel was filled into a prefilled syringe and sterilized by moist heat at 121° C. for 15 minutes to obtain a final product containing a gel composition of biphasic microspheres and a biodegradable polymer material.

[0119] Example 7 Physical crosslinking of three-phase gel

[0120] 2.7 g of the biphasic microspheres from Example 4 were soaked in 50 mL of a pH 9.0 PBS solution for surface charge modification, resulting in a negative charge on the microsphere surface. After soaking for 30 minutes, the biphasic microspheres were separated and removed, drained, and physically mixed with 15.3 g of the cross-linked hyaluronic acid gel from Example 1. This allowed the carboxylate anions on the polylactic acid surface to electrostatically crosslink with the ammonium cations in the cross-linked hyaluronic acid, and also allowed the calcium on the surface of the biphasic microspheres to form coordination bonds with the carboxylates of the cross-linked sodium hyaluronate gel. After uniform mixing, the three-phase gel was filled into a prefilled syringe and sterilized by moist heat at 121° C. for 15 minutes to obtain a gel composition containing biphasic microspheres and a biodegradable polymer material.

[0121] Example 8 Physical crosslinking of three-phase gel

[0122] 4.5 g of the biphasic microspheres from Example 4 were soaked in 50 mL of a pH 9.0 PBS solution for surface charge modification, resulting in a negative charge on the microsphere surface. After soaking for 30 minutes, the biphasic microspheres were separated, drained, and physically mixed with 13.5 g of the cross-linked hyaluronic acid gel from Example 1. After uniform mixing, the three-phase gel was filled into a prefilled syringe and sterilized by moist heat at 121°C for 15 minutes to obtain a gel composition containing the biphasic microspheres and a biodegradable polymer material.

[0123] Example 9 Physical crosslinking of three-phase gel

[0124] 4.5 g of the biphasic microspheres from Example 4 were soaked in 50 mL of a pH 9.0 PBS solution for surface charge modification, resulting in a negative charge on the microsphere surface. After soaking for 30 minutes, the biphasic microspheres were separated and removed, drained, and physically mixed with 13.5 g of the cross-linked hyaluronic acid gel from Example 2. This allowed the carboxylate anions on the polylactic acid surface to electrostatically crosslink with the ammonium cations in the cross-linked hyaluronic acid, and also allowed the calcium on the surface of the biphasic microspheres to form coordination bonds with the carboxylates of the cross-linked sodium hyaluronate gel. After uniform mixing, the three-phase gel was filled into a prefilled syringe and sterilized by moist heat at 121° C. for 15 minutes to obtain a final product containing a gel composition of biphasic microspheres and a biodegradable polymer material.

[0125] Example 10 Physical crosslinking of three-phase gel

[0126] 4.5 g of the biphasic microspheres from Example 4 were soaked in 50 mL of a pH 9.0 PBS solution for surface charge modification, resulting in a negative charge on the microsphere surface. After soaking for 30 minutes, the biphasic microspheres were separated and removed, drained, and physically mixed with 13.5 g of the cross-linked hyaluronic acid gel from Example 3. This allowed the carboxylate anions on the polylactic acid surface to electrostatically crosslink with the ammonium cations in the cross-linked hyaluronic acid, and also allowed the calcium on the surface of the biphasic microspheres to form coordination bonds with the carboxylates of the cross-linked sodium hyaluronate gel. After uniform mixing, the three-phase gel was filled into a prefilled syringe and sterilized by moist heat at 121° C. for 15 minutes to obtain a gel composition containing biphasic microspheres and a biodegradable polymer material.

[0127] Example 11 Physical crosslinking of three-phase gel

[0128] 4.5 g of the biphasic microspheres from Example 5 were soaked in 50 mL of a pH 9.0 PBS solution for surface charge modification, resulting in a negative charge on the microsphere surface. After soaking for 30 minutes, the biphasic microspheres were separated, drained, and physically mixed with 13.5 g of the cross-linked hyaluronic acid gel from Example 1. After uniform mixing, the three-phase gel was filled into a prefilled syringe and sterilized by moist heat at 121°C for 15 minutes to obtain a gel composition containing the biphasic microspheres and a biodegradable polymer material.

[0129] Example 12 Chemical crosslinking of three-phase gel

[0130] 30 g of the biphasic microspheres obtained in Example 4 were added to 350 mL of purified water and 2.0 g of ethylenediamine. The pH of the solution was adjusted to 5.5 using 1 mol / L hydrochloric acid solution. 2.0 g of EDC and 0.4 g of NHS were added for surface amino modification. The reaction was carried out at 40°C for 16 h. The microspheres were separated by filtration and washed with purified water to a pH range of 7.0-7.1. The microspheres were then dried in a vacuum drying oven at 40°C overnight to obtain surface amino-modified biphasic microspheres.

[0131] Weigh 1.5g of sodium hyaluronate (molecular weight 500kDa) and add 37.5ml of purified water. After complete dissolution, the concentration of hyaluronic acid is now 40mg / mL. Add 29.7g of surface-amino-modified biphasic microspheres to the hyaluronic acid solution. Use 0.1mol / L hydrochloric acid solution to adjust the pH value of the hyaluronic acid solution to about 5.5, then add and stir evenly. Add 0.3g of EDC and 0.06g of NHS (20% of the EDC mass) and continue stirring evenly. Seal and place in a 40°C forced air drying oven to react for 14 hours. After the reaction is completed, add 200mL of anhydrous ethanol to completely dehydrate the gel. Separate the precipitate and wash it continuously with 200mL of anhydrous ethanol five times. Then place the precipitate in a vacuum oven and vacuum dry it at -0.090MPa at 40°C for 24 hours. After complete drying, 4.73 g of the dry gel was taken, 5.14 mL of phosphate buffer solution was added, 4.05 mL of 1% lidocaine hydrochloride was added, and 4.18 mL of sterile water for injection was added. After the gel was completely swollen, the gel was filled into a prefilled syringe and sterilized with wet heat at 121°C for 15 min to obtain a gel composition containing biphasic microspheres and biodegradable polymer materials.

[0132] Comparative Example 1: Preparation of physical blend gel of PLA microspheres and cross-linked hyaluronic acid

[0133] Preparation of PLA microspheres:

[0134] Weigh 1.8g of polylactic acid (molecular weight 100kDa) and place it in a 50mL beaker. Then add 50mL of dichloromethane and stir with a spoon to completely dissolve it. Then filter it into a beaker with a 10mm nylon 66 syringe filter. Then add 135mL of polyvinyl alcohol solution (1.5wt%) to a 300mL three-necked flask and place it in a 30℃ water bath. Then stir it mechanically at a rate of 400r / min. After the ultrasonic wave ends, slowly add the dichloromethane turbidity to the polyvinyl alcohol solution and stir overnight to evaporate and remove the dichloromethane.

[0135] The suspension obtained in the previous step was diluted to 500 mL with purified water, and then allowed to stand for 1 hour. The upper suspension was poured off and repeated twice. The precipitate was redissolved and filtered with a 0.45 μm water filter membrane to remove the liquid. The obtained solid was then dispersed with 200 mL of purified water and filtered again. This was repeated four times. The obtained solid was then redissolved with 150 mL of purified water and added to a Schott bottle. The product was placed in a 100°C oven and heated for 30 minutes. It was taken out and cooled and filtered. The product was washed three times with purified water. The solid obtained from the last wash was transferred to a culture dish and placed in a vacuum drying oven at 40°C for drying overnight to obtain the final product, PLA microspheres.

[0136] 2.7 g of the aforementioned PLA microspheres were soaked in 50 mL of PBS solution (pH 9.0) for surface charge modification, resulting in a negative charge on the microsphere surface. After soaking for 30 minutes, the microspheres were separated, drained, and physically mixed with 15.3 g of the cross-linked hyaluronic acid gel from Example 1. This electrostatically crosslinked the carboxylate anions on the polylactic acid surface with the ammonium ions in the cross-linked hyaluronic acid. After uniform mixing, the gel was filled into prefilled syringes and sterilized by moist heat at 121°C for 15 minutes to obtain the final gel.

[0137] Comparative Example 2: Preparation of physical blend gel of nano-scale HAP and cross-linked hyaluronic acid

[0138] 2.7 g of nano-hydroxyapatite (HAP) was soaked in 50 mL of PBS (pH 9.0) for surface charge modification, resulting in a negative charge on the HAP surface. After soaking for 30 minutes, the HAP was separated, drained, and physically mixed with 15.3 g of the cross-linked hyaluronic acid gel from Example 1 to form coordination bonds between the calcium in the nano-hydroxyapatite and the carboxylate groups in the cross-linked sodium hyaluronate gel. After uniform mixing, the gel was filled into prefilled syringes and sterilized by moist heat at 121°C for 15 minutes to obtain the final gel.

[0139] Performance Testing

[0140] Test Example 1: Microsphere Morphology

[0141] Electron microscopy image 1(A) shows that the dual-phase microspheres of Example 4 are evenly dispersed and have uniform particle size. Furthermore, the SEM images in Figures 1(B) and (C) show that the PLA microspheres without HAP (PLA microspheres from Comparative Example 1) have a smooth surface, while the PLA-HAP dual-phase microspheres with HAP added exhibit nanoscale HAP uniformly dispersed within the PLA matrix (Example 4).

[0142] Test Example 2: Mechanical Properties

[0143] Elastic modulus test method: Samples obtained from Examples 6-12 and Comparative Examples 1-2 were divided into two groups, pre-sterilization and post-sterilization, with 2.0 mL of each sample taken. The elastic modulus (G') of the gel was measured using a TA DHR-2 plate rheometer, and the elastic modulus loss rate was calculated. The G' loss rate was calculated using the following formula:

[0144] G' loss rate = (G' before sterilization - G' after sterilization) / G' before sterilization

[0145] The rheometer parameters are: operating gap: 1000 mm, loading gap: 45000 m, operating temperature: 37° C., deformation: 1%, frequency: 0.9 Hz, and operating time: 60 s.

[0146] Pushing force testing method: Use a syringe loaded with the sample and a 23G, 50mm blunt needle. Use an electronic universal tensile testing machine at a speed of 30mm / min to test the pushing force of the sterilized product and record the data. The test results are shown in Table 1.

[0147] Table 1

[0148] As shown in Table 1, compared to Comparative Example 1, the gel composition samples obtained by physical crosslinking in Examples 6-11 and the gel composition sample obtained by chemical crosslinking in Example 12 exhibited higher elastic moduli and improved thermal stability, indicating that crosslinking contributes to the increase in elastic modulus and, to a certain extent, enhances the thermal stability of the gel composition. Furthermore, the extrusion forces of the samples of the present invention were all below 23 N, making them suitable for clinical injection.

[0149] The gel product of Comparative Example 1 contained only PLA microspheres, resulting in a low sample extrusion force. Although PLA and HA were physically cross-linked, no HAP was added. Compared to Example 7, which had the same microsphere content (15%), the resulting gel composition had a lower elastic modulus and a much higher heat loss rate than Example 7. This indicates that in the present example sample, after HAP formed composite microspheres with PLA, nano-HAP, using micron-sized PLA as a carrier, was introduced into the macroscopic network structure of cross-linked hyaluronic acid (the cross-linked hyaluronic acid particles were also micron-sized). Calcium ions complexed with the carboxyl and hydroxyl groups in the hyaluronic acid that had not undergone cross-linking with PLA, filling the gaps in the cross-linked hyaluronic acid network and resulting in a tighter network structure for the gel composition. Furthermore, the complexation between HAP and HA shortened the distance between the PLA and HA molecular chains, thereby improving the efficiency of the cross-linking reaction between the two, resulting in a composition product with improved elastic modulus and thermal stability.

[0150] In Comparative Example 2, nanoscale HAP (15%) was physically blended with cross-linked hyaluronic acid. Compared to Example 7, which had the same microsphere content (15%), the elastic modulus improved, with a loss of only 1.28%, reflecting a certain degree of complexation between HAP and cross-linked HA. However, the high extrusion force of 35N made it unsuitable for clinical use. Furthermore, due to the direct addition of nanoscale HAP in Comparative Example 2, the gel composition struggled to form a tighter network structure. By forming biphasic microspheres with HAP and PLA, the HAP was loaded onto the micron-sized PLA carrier, further forming a tighter network structure with the cross-linked hyaluronic acid gel, resulting in enhanced thermal stability.

[0151] Test Example 3: Compression Test

[0152] Test method: 0.5 g of the samples of Examples 6-12 and Comparative Examples 1-2 were evenly squeezed onto a glass slide to form an approximately hemispherical shape. A cover glass was placed on the sample, and a weight was added to the cover glass to expand the sample diameter to 1 cm. At this time, the mass of the cover glass and the weight was weighed and recorded.

[0153] Photos of the samples before and after the compressive performance test are shown in Figure 2, and the test results are shown in Table 2 and Figure 3.

[0154] Table 2

[0155] In order to press the sample into discs of the same size, the size of the mass reflects the compressive resistance of the sample.

[0156] It can be seen from Table 2 and Figure 3 that Examples 6-12 can all withstand a larger mass, and with the increase of the microsphere content in the gel composition and the increase of the HA cross-linking degree, the mass of the heavy object that can be supported is larger. For example, the sample of Example 10 can withstand a mass of 8.8 g, which shows that the sample of Example 10 has the strongest compressive resistance and the best supporting performance.

[0157] The sample in Example 1, containing 5% biphasic microspheres, had the same load-bearing capacity, and thus the same compressive resistance, as the sample in Comparative Example 1, containing 15% PLA microspheres. This demonstrates that the present invention significantly improves the compressive resistance of the gel composition sample by adding a small amount of biphasic microspheres. This is due to the physical crosslinking between the biphasic microspheres and sodium hyaluronate, which enhances the compressive resistance of the three-phase composite gel. The sample in Comparative Example 2 exhibits higher compressive resistance, both due to the higher microsphere content (15%) and because the microspheres are made of pure nano-HAP inorganic material.

[0158] Test Example 4: Viscosity Test

[0159] Testing Method: Each sample (1 mL) was loaded into a syringe using a 23G, 50mm blunt needle. The maximum drawn length was measured at 30 mm / min using an electronic universal tensile testing machine, and the data was recorded. A greater maximum drawn length indicates greater viscosity and cohesion, making the sample more suitable for soft tissue augmentation and shaping. Test results are shown in Figure 4 and Table 3.

[0160] Table 3

[0161] It can be seen from the test results that the maximum drawing lengths of the samples of Examples 6-12 of the present invention are all above 39 mm, and the viscosity is excellent. As the microsphere content and the degree of cross-linking of sodium hyaluronate increase, the maximum drawing length increases. The maximum drawing length of the sample of Example 10 can reach 53 mm, and still has a good pushing force (23 N, see Table 1), meeting the requirements of clinical use. In the case of 15% microsphere content, the maximum drawing of Comparative Examples 1-2 is lower than that of Example 6 with only 5% microsphere content, which also illustrates that the interaction between the two-phase microspheres and sodium hyaluronate comprehensively improves the performance of the three-phase composite gel composition and reduces the cost of raw materials.

[0162] Test Example 5: Liquidity Test

[0163] 0.5g of each sample from Examples 6-12 and Comparative Examples 1-2 (1 mL) was evenly squeezed onto a polytetrafluoroethylene plate to form a roughly hemispherical shape. The plate was then held upright, and the hemispheres were held under gravity for 1 hour. The flow distance of the sample on the plate was recorded. A smaller sample flow distance indicates that the sample is less likely to shift, has better cohesion, and is more suitable for soft tissue filling and shaping. Test results are shown in Figure 5 and Table 4.

[0164] Table 4

[0165] The test results show that the sample in Example 6 of the present invention flowed a distance of 6 mm, while the samples in Examples 7-12 did not flow after being placed for 1 hour. This shows that by rationally controlling the microsphere content, HA crosslinking degree, and other parameters in the composition, the prepared gel composition has good cohesion and does not produce displacement. In contrast, the flow distance of Comparative Example 1, at a microsphere content of 15%, was 8 mm, which is higher than the flow distance (6 mm) of the sample in Example 6 of the present invention with a microsphere content of 5%. This also shows that by introducing biphasic microspheres, the interaction between the microspheres and sodium hyaluronate is enhanced, thereby enhancing the cohesion of the three-phase composite gel composition product. Since the microspheres in Comparative Example 2 are pure nano-HAP inorganic material with a content of 15%, the prepared gel product is prone to solidification or cement-like phenomena, which is not conducive to push injection.

[0166] The gel composition of the present invention, comprising biphasic microspheres and a biodegradable polymer material, has the advantages of being non-displaceable, having good viscosity, strong pressure resistance, resistance to thermal degradation, and resistance to enzymatic hydrolysis, through the interaction between the biphasic microspheres and the polymer material. The gel composition combines the advantages of the three materials and can be used for filling, repairing, and shaping biological tissues.

[0167] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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 gel composition comprising biphasic microspheres and a biodegradable polymer material, It is characterized in that The gel composition comprises dual-phase microspheres, biodegradable polymer materials and auxiliary materials. The dual-phase microspheres are polylactic acid / inorganic material dual-phase microspheres. The dual-phase microspheres and the biodegradable polymer materials are cross-linked, and the cross-linking includes physical cross-linking or chemical cross-linking.

2. The composition according to claim 1, It is characterized in that The auxiliary materials include local anesthetics, hydrochloric acid solution, and sodium chloride solution or phosphate buffer solution; the auxiliary materials are added to the biodegradable polymer material before the two phase microspheres and the biodegradable polymer material are cross-linked, or added after the two are cross-linked; Preferably, the osmotic pressure of the phosphate buffer solution or the sodium chloride solution is 200 to 400 mOsm / L, more preferably, 220 to 380 mOsm / L, particularly preferably, 250 to 350 mOsm / L; Preferably, the local anesthetic is selected from one or a combination of amide type and ester type, and the concentration of the local anesthetic in the composition is 1 to 5 mg / mL.

3. The composition according to claim 1 or 2, It is characterized in that The content of the dual-phase microspheres in the gel composition is 5-35 wt %, preferably 10-25 wt %.

4. The composition according to claim 1 or 2, It is characterized in that The inorganic material in the dual-phase microspheres is selected from one or a combination of two or more of calcium carbonate, calcium phosphate and calcium tartrate; preferably, the calcium phosphate is preferably calcium hydroxyapatite; the content of the inorganic material in the dual-phase microspheres is 5% to 15%; and the average particle size of the dual-phase microspheres is 10 to 80 μm.

5. The composition according to claim 1 or 2, It is characterized in that The concentration of the biodegradable polymer material in the gel composition is 10-40 mg / mL, and the biodegradable polymer material is selected from one or a combination of two or more of hyaluronic acid or its salt, cellulose, collagen, chitosan and gelatin, preferably hyaluronic acid or its salt.

6. The composition according to claim 1 or 2, It is characterized in that The physical crosslinking includes modifying the surface charge of the biphasic microspheres to form an electrostatic crosslink with the biodegradable polymer material; preferably, the surface charge modification of the biphasic microspheres includes immersing the biphasic microspheres in an alkaline buffer solution to separate them.

7. The composition according to claim 1 or 2, It is characterized in that The chemical cross-linking comprises performing amino modification on the biphasic microspheres and then performing a chemical cross-linking reaction with a biodegradable polymer material; preferably, the amino modification comprises reacting the biphasic microspheres with an amine compound.

8. A method for preparing the composition according to any one of claims 1 to 7, It is characterized in that The steps include: Step 1: preparing biodegradable polymer materials; Step 2: preparing biphasic microspheres; Step 3: Physically cross-linking the dual-phase microspheres of step 2 and the biodegradable polymer material of step 1.

9. The preparation method according to claim 8, It is characterized in that Step 1 includes: The biodegradable polymer material is dissolved in a solvent, and auxiliary materials are added to allow swelling.

10. The preparation method according to claim 9, It is characterized in that Step 2 includes: 2-1) dissolving polylactic acid (PLA) in dichloromethane to prepare a solution, and filtering; 2-2) adding inorganic materials, performing ultrasonication and stirring to completely disperse them in the solution to form a suspension; 2-3) preparing a polyvinyl alcohol solution, and dropping the suspension obtained in 2-2) into the solution to form microspheres under stirring, shearing and emulsification; 2-4) The emulsified solution is stirred to evaporate the dichloromethane, and then the obtained intermediate product is washed and filtered.

11. The preparation method according to any one of claims 8 to 10, It is characterized in that In step 3, the physical crosslinking comprises: 3-1) modifying the surface charge of the biphasic microspheres obtained in step 2 to obtain modified biphasic microspheres carrying negative ions on the surface; 3-2) mixing the obtained modified dual-phase microspheres with the polymer material obtained in step 1 to undergo electrostatic crosslinking to obtain the composition; Preferably, the surface charge modification of the biphasic microspheres comprises separating the biphasic microspheres by immersing them in an alkaline buffer solution; more preferably, the alkaline buffer solution is a PBS solution.

12. A method for preparing the composition according to any one of claims 1 to 7, It is characterized in that The steps include: Step 1': preparing biodegradable polymer materials; Step 2': preparing biphasic microspheres; Step 3': chemically cross-linking the dual-phase microspheres obtained in step 2' and the biodegradable polymer material in step 1', and adding auxiliary materials after the reaction to obtain the composition.

13. The preparation method according to claim 12, It is characterized in that Step 1' includes dissolving a biodegradable polymer material in a solvent; Step 2' is the same as step 2 in claim 10; Step 3' comprises: 3'-1) performing amino modification on the polylactic acid in the dual-phase microspheres prepared in step 2'; 3'-2) chemically cross-linking the modified biphasic microspheres with the biodegradable polymer material of step 1' to obtain the composition; preferably, the biodegradable polymer material is hyaluronic acid or a salt thereof.

14. The preparation method according to claim 13, It is characterized in that The amino modification described in 3'-1) includes reacting the biphasic microspheres with amine compounds; 3'-2) the cross-linking reaction includes coupling the modified biphasic microspheres with hyaluronic acid or its salt in the presence of a carbodiimide activator.

15. Use of the composition according to any one of claims 1 to 7 or the composition obtained by the preparation method according to any one of claims 8 to 14 in the preparation of a drug carrier, a tissue filler or a tissue repair material.

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