Hydroxyapatite core-spun microsphere for injection filling and preparation method thereof

Abstract

The invention belongs to the technical field of passive filling materials for medical instruments, and discloses hydroxyapatite core-spun microspheres for injection filling and a preparation method of the hydroxyapatite core-spun microspheres. The hydroxyapatite core-spun microsphere is composed of inner-layer hydroxyapatite and an outer-layer coating material, the brittleness and roundness of the surface of the hydroxyapatite microsphere can be improved, the inflammatory reaction and granuloma occurrence rate of an injection site can be reduced, more importantly, the risk that the hydroxyapatite microsphere is gathered and fused with surrounding skeleton tissue can be improved, and safety is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of passive filling materials for medical devices, and more particularly to a hydroxyapatite core-shell microsphere for injection filling and a preparation method thereof. Background Art

[0002] Hydroxyapatite is usually also referred to as HA bioceramics, and its molecular formula is Ca 1 0(PO 4 ) 6 (OH) 2 or Ca 6 (PO 4 ) 3 (OH), and its structure is a hexagonal crystal system P63 / m space group. All along, hydroxyapatite has been widely used in the medical field because of its composition and structure identical to those of human bones, good osteoconductivity and excellent biocompatibility.

[0003] Radiesse is a product of the German century-old Mohs medical beauty company, which is composed of 30% hydroxyapatite microspheres and 70% gel (sodium carboxymethyl cellulose) and is used for subcutaneous injection filling and can stimulate collagen regeneration. Due to the good biocompatibility and slow degradation performance of hydroxyapatite, Radiesse has been widely used in the field of medical beauty. However, due to the rough surface and relatively large brittleness of hydroxyapatite, powder shedding is likely to occur during transportation, and a relatively serious inflammatory reaction is likely to occur at the injection site, and blood vessel blockage may occur and then granuloma may form. More seriously, the degradation of hydroxyapatite is slow, and after long-term contact at the injection site, it is likely to fuse with the surrounding bone structure and needs to be removed by surgery, seriously affecting the use safety.

[0004] To solve the above problems, researchers began to add various polymer materials such as polylactic acid to nano-hydroxyapatite in order to improve the surface properties of hydroxyapatite microspheres. However, it is not easy for the polymer materials to bind to the surface of hydroxyapatite, and materials such as chitosan need to be added, and then prepared into composite materials by co-precipitation and other methods. Although it can improve the brittleness of hydroxyapatite to a certain extent, since the hydroxyapatite on the material surface is not completely covered by the polymer materials, there is still a risk of powder shedding and bone fusion. CN101756908A polyester-coated hydroxyapatite microspheres and a preparation method thereof disclose that by utilizing the porosity of hydroxyapatite, after adsorbing the corresponding drug, the drug-loaded microspheres are coated by methods such as drying in liquid, fluidized bed coating, spray drying, etc., in order to achieve the effect of controlling the drug release rate. Among them, the polyester coating material is in direct contact with the hydroxyapatite completely. As the encapsulated drug is released, the polyester coating material is separated from the internal hydroxyapatite, and still cannot solve the problem of bone fusion during the slow degradation of hydroxyapatite in the body.

[0005] Centrifugal granulation coating machines are commonly used for powder granulation / pelletization of oral solids or pellet coating. When used for coating, a ventilation heating method is mostly adopted to dry the binder while coating. The generally particle size of pellets and the like treated conventionally is above 80 mesh. When coating microspheres with a smaller particle size, problems such as easy adhesion of microspheres, serious static electricity, the coating material not contacting the microspheres and being directly dried into powder during the spraying process, and very low utilization rate of the coating material are likely to occur.

[0006] Therefore, how to improve the binding degree between the polymer material and the surface of hydroxyapatite and to improve the risk of aggregation of hydroxyapatite microspheres and fusion with the surrounding skeletal tissue is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention provides a hydroxyapatite core-shell microsphere for injection filling and a preparation method thereof.

[0008] The technical concept of the present invention is: directly wrapping polylactic acid, polycaprolactone or polyacrylic resin on the surface of hydroxyapatite to prepare a hydroxyapatite core-shell microsphere, which can improve the roundness and friability of the surface of the hydroxyapatite microsphere, reduce the incidence of inflammatory reaction and granuloma at the injection site. More importantly, it can improve the risk of aggregation of hydroxyapatite microspheres and fusion with the surrounding skeletal tissue, and improve safety. Surprisingly, through the low-temperature centrifugal granulation coating method, no chitosan or other drugs need to be added to the polymer material, and it can also bind well on the surface of hydroxyapatite and form a uniform coating, realizing the direct contact between hydroxyapatite and the polyester material, so that the acidity of the polyester material is neutralized by the alkalinity of hydroxyapatite during the in vivo degradation process, further reducing the irritation and inflammatory reaction of the two materials to the injection site.

[0009] One of the purposes of the present invention is to provide a hydroxyapatite core-shell microsphere for injection filling. The hydroxyapatite core-shell microsphere is composed of internal hydroxyapatite and an outer coating material, and the particle size of the hydroxyapatite core-shell microsphere is 25-60 μm. Among them, the dosage of the internal hydroxyapatite microspheres is 70 wt% - 95 wt% of the total mass of the hydroxyapatite core-shell microspheres, and the dosage of the outer coating material is 5 wt% - 30 wt% of the total mass of the hydroxyapatite core-shell microspheres.

[0010] Preferably, the friability of the hydroxyapatite core-shell microsphere is ≤ 0.5%.

[0011] The beneficial effect of adopting the above technical solution is: to avoid powder shedding during transportation and reduce local irritation and inflammatory reaction caused by powder shedding.

[0012] Preferably, the coating material is selected from at least one of polylactic acid, polycaprolactone, and polyacrylic resin.

[0013] Further preferably, the polylactic acid is selected from at least one of poly-L-lactic acid, poly-D-lactic acid, and poly-rac-lactic acid.

[0014] Preferably, the dosage of the hydroxyapatite microspheres is 75 wt% - 85 wt% of the total mass of the hydroxyapatite core-shell microspheres, and the dosage of the coating material is 15 wt% - 25 wt% of the total mass of the hydroxyapatite core-shell microspheres.

[0015] The second object of the present invention is to provide a method for preparing hydroxyapatite core-shell microspheres for injection filling, comprising the following steps:

[0016] (1) Weigh the hydroxyapatite and the coating material according to the above scheme;

[0017] (2) Dissolve the coating material in a solvent to obtain a coating material solution;

[0018] (3) Add the hydroxyapatite microspheres to a centrifugal granulation coating machine;

[0019] (4) Through centrifugal granulation coating, coat the coating material solution on the surface of the hydroxyapatite at a low temperature to obtain hydroxyapatite core-shell microspheres;

[0020] (5) Screen the hydroxyapatite core-shell microspheres on a screening machine, and collect the hydroxyapatite core-shell microspheres with a particle size of 25 μm - 60 μm.

[0021] Preferably, in step (2), the solvent is selected from at least one of dichloromethane, ethanol, isopropanol, and acetone.

[0022] Preferably, in step (2), the mass concentration of the coating material is 5 wt% - 20 wt%.

[0023] Preferably, in step (4), the inlet air temperature of the centrifugal granulation coating machine is 5 - 15 °C, and the atomization pressure of the spray gun is 3.0 - 4.0 bar.

[0024] Through the above technical solutions, compared with the prior art, the beneficial effects obtained by the present invention are as follows:

[0025] 1) In the present invention, a layer of polymer material is coated on the surface of the hydroxyapatite microspheres, significantly improving the roundness and friability of the microsphere surface; reducing the incidence of inflammatory reactions and granulomas at the injection site, and significantly reducing the incidence of adverse reactions of the filling product;

[0026] 2) The polymer material is coated on the surface of the hydroxyapatite microspheres according to the ratio described in the present invention, which can reduce the aggregation of the hydroxyapatite microspheres, avoid fusion with the surrounding skeletal tissue, significantly reduce the incidence of serious adverse reactions, and improve the safety of the filling product.

[0027] 3) The present invention adopts the centrifugal granulation coating method, innovatively reducing the inlet air temperature, enabling the polymer material to bind well to the surface of hydroxyapatite and form a uniform coating, reducing the use of other materials such as chitosan, and further improving the safety of the product. Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0029] Figure 1 SEM photograph of the hydroxyapatite core-shell microspheres prepared in Example 1

[0030] Figure 2 SEM photograph of the untreated hydroxyapatite microspheres

[0031] Figure 3 SEM photograph of the injection filled with the hydroxyapatite core-shell microspheres prepared in Example 6

[0032] Figure 4 SEM photograph of the injection filled with the hydroxyapatite microspheres prepared in Comparative Example 2

[0033] Figure 5 Particle size distribution diagram of the hydroxyapatite core-shell microspheres prepared in Example 1 measured by a laser particle size analyzer

[0034] Figure 6 Particle size distribution diagram of the untreated hydroxyapatite microspheres measured by a laser particle size analyzer Detailed Description of the Embodiments

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0036] Example 1: Preparation of Hydroxyapatite Core-Shell Microspheres

[0037] 1) Add 60 g of poly-L-lactic acid powder to 540 g of dichloromethane and stir until completely dissolved;

[0038] 2) Add 340 g of hydroxyapatite microspheres with a particle size of 25 - 50 μm to the Granurex centrifugal granulation coater of Furendo, Japan;

[0039] 3) Start the centrifugal granulation coating machine, adjust the appropriate centrifugal speed and air intake volume, so that the material makes a centrifugal motion in the granulator, and set the inlet air temperature to 10 °C (the inlet air unit of the coating machine is temperature-controlled by cooling with chilled water).

[0040] 4) Wait until the temperature of the material in the granulator drops below 15 °C, set the atomization pressure to 3.0 bar, and through a peristaltic pump, transport the dissolved poly-L-lactic acid dichloromethane solution to the centrifugal granulation machine spray gun at a speed of 10 - 20 g / min, turn on atomization, and coat the dissolved outer coating material on the surface of hydroxyapatite by centrifugal granulation at low temperature. After the liquid spraying is completed, continue to run for 30 min for drying to obtain hydroxyapatite core-shell microspheres.

[0041] 5) Install a 25 μm sieve and a 60 μm sieve on the screening machine, start the screening machine, add the hydroxyapatite core-shell microspheres prepared in 4) to the screening machine, and collect the core-shell microspheres in the 25 μm - 60 μm part.

[0042] Example 2: Preparation of hydroxyapatite core-shell microspheres

[0043] 1) Add 20 g of polycaprolactone powder to 380 g of dichloromethane and stir until completely dissolved.

[0044] 2) Add 380 g of hydroxyapatite microspheres with a particle size of 25 - 50 μm to the Granurex centrifugal granulation coating machine made in Japan.

[0045] 3) Start the centrifugal granulation coating machine, adjust the appropriate centrifugal speed and air intake volume, so that the material makes a centrifugal motion in the granulator, and set the inlet air temperature to 12 °C (the inlet air unit of the coating machine is temperature-controlled by cooling with chilled water).

[0046] 4) Wait until the temperature of the material in the granulator drops below 17 °C, set the atomization pressure to 3.5 bar, and through a peristaltic pump, transport the dissolved poly-L-lactic acid dichloromethane solution to the centrifugal granulation machine spray gun at a speed of 10 - 20 g / min, turn on atomization, and coat the dissolved outer coating material on the surface of hydroxyapatite by centrifugal granulation at low temperature. After the liquid spraying is completed, continue to run for 30 min for drying to obtain hydroxyapatite core-shell microspheres.

[0047] 5) Install a 25 μm sieve and a 60 μm sieve on the screening machine, start the screening machine, add the hydroxyapatite core-shell microspheres prepared in 4) to the screening machine, and collect the core-shell microspheres in the 25 μm - 60 μm part.

[0048] Example 3: Preparation of hydroxyapatite core-shell microspheres

[0049] 1) Add 120 g of polyacrylic resin powder to 480 g of a 50% isopropanol / acetone solution and stir until completely dissolved;

[0050] 2) Add 380 g of hydroxyapatite microspheres with a particle size of 25 - 50 μm to a Granurex centrifugal granulation coater from Furuta, Japan;

[0051] 3) Start the centrifugal granulation coater, adjust the appropriate centrifugal speed and air intake volume to make the material perform a centrifugal motion in the granulator, and set the inlet air temperature to 15 °C (the inlet air unit of the coater is temperature-controlled by cooling with chilled water).

[0052] 4) Wait until the temperature of the material in the granulator drops below 20 °C, set the atomization pressure to 4.0 bar, and through a peristaltic pump, transport the dissolved poly-L-lactic acid dichloromethane solution to the centrifugal granulator spray gun at a speed of 5 - 10 g / min, turn on atomization, and coat the dissolved outer coating material on the surface of hydroxyapatite by centrifugal granulation at low temperature. After the liquid spraying is completed, continue to run for 30 min for drying to obtain hydroxyapatite core-shell microspheres;

[0053] 5) Install a 25-μm sieve and a 60-μm sieve on the screening machine, start the screening machine, add the hydroxyapatite core-shell microspheres prepared in 4) to the screening machine, and collect the core-shell microspheres in the 25-μm - 60-μm part.

[0054] Example 4: Preparation of hydroxyapatite core-shell microsphere filling material

[0055] 1) Add 80 g of polyacrylic resin powder to 720 g of a 95% ethanol solution and stir until completely dissolved;

[0056] 2) Add 320 g of hydroxyapatite microspheres with a particle size of 25 - 50 μm to a Granurex centrifugal granulation coater from Furuta, Japan;

[0057] 3) The subsequent preparation process is the same as that of Example 3.

[0058] Example 5: Preparation of hydroxyapatite core-shell microsphere filling material

[0059] 1) Add 100 g of poly-D-lactic acid powder to 900 g of dichloromethane and stir until completely dissolved;

[0060] 2) Add 300 g of hydroxyapatite microspheres with a particle size of 25 - 50 μm to a Granurex centrifugal granulation coater from Furuta, Japan;

[0061] 3) The subsequent preparation process is the same as that of Example 1.

[0062] Example 6: Preparation of hydroxyapatite core-shell microsphere filling injection

[0063] 1) Add 2 g of glycerol to 67 g of water for injection, mix well, then add 1 g of sodium carboxymethylcellulose, disperse evenly, and allow to swell overnight to form a gel.

[0064] 2) Add 30 g of the hydroxyapatite core-shell microspheres prepared in Example 1 to the gel prepared in 1), and disperse evenly.

[0065] 3) Fill into 1 mL pre-filled syringes, sterilize by γ-irradiation, and prepare the injectable preparation for filling.

[0066] Example 7: Preparation of Injectable Hydroxyapatite Core-Shell Microsphere Filling

[0067] The preparation method is the same as that of Example 6, and the hydroxyapatite core-shell microspheres prepared in Example 1 are replaced with those prepared in Example 2.

[0068] Comparative Example 1: Preparation of Hydroxyapatite Core-Shell Microspheres by Centrifugal Granulation and Coating at Room Temperature

[0069] The preparation method is the same as that of Example 1, and the inlet air temperature is adjusted to 30 °C.

[0070] Comparative Example 2: Preparation of Injectable Hydroxyapatite Microsphere Filling

[0071] The preparation method is the same as that of Example 6, and the hydroxyapatite core-shell microspheres are replaced with untreated hydroxyapatite microspheres.

[0072] Comparative Example 3: Preparation of Filling Agent of Hydroxyapatite Core-Shell Microspheres Containing Lidocaine

[0073] Take an appropriate amount of hydroxyapatite microspheres, add lidocaine hydrochloride solution, mix at 50 - 120 r / min with constant temperature oscillation for 6 hours, filter to collect the microspheres, and freeze-dry to obtain drug-loaded hydroxyapatite microspheres.

[0074] The preparation method is the same as that of Example 1 to obtain hydroxyapatite core-shell microspheres containing lidocaine. The preparation method is the same as that of Example 6 to prepare a filling agent of hydroxyapatite core-shell microspheres containing lidocaine.

[0075] Experiment 1: Physicochemical Property Test and Comparison of Hydroxyapatite Core-Shell Microspheres Prepared in Examples 1 - 5 and Hydroxyapatite without Coating Layer

[0076] 1) The particle size was measured using a BT-9300ST laser particle size distribution analyzer.

[0077] 2) The sphericity was tested using a scanning electron microscope and calculated using image processing software.

[0078] 3) Friability: Take 100 g of the material, add it to the fluidized bed, and set the air inlet volume to 120 m 3Without heating, boil for 2 h, then take out the material, weigh it, and calculate the loss weight ratio, which is the friability.

[0079] 4) Coating material utilization rate: (weight of the material after coating - weight of hydroxyapatite before coating) / coating material input * 100%.

[0080] Table 1 Physicochemical property test results of hydroxyapatite core-shell microspheres and untreated hydroxyapatite microspheres

[0081]

[0082] As can be seen from Table 1, compared with Comparative Example 1 and untreated microspheres, Examples 1-5 have more uniform particle size, better sphericity and friability.

[0083] Experiment 2: Clinical experiment comparison between hydroxyapatite core-shell microsphere-filled injections and untreated hydroxyapatite microspheres

[0084] Test method:

[0085] Test products: Example 6, Example 7, Example 7 + lidocaine, Comparative Example 2, Comparative Example 3

[0086] Healthy subjects aged 30-60 years old;

[0087] Injection site: nasolabial fold;

[0088] Injection dose: 0.5-1.5 ml

[0089] Observation period: Observe and record the filling effect and side effects at 1 week, 3 months, 12 months, and 24 months after injection respectively. The filling effect was evaluated by 3 blinded reviewers using the Global Aesthetic Improvement Scale (GAIS) through photos.

[0090] Table 2 Clinical effect comparison between hydroxyapatite core-shell microsphere-filled injections and untreated hydroxyapatite microspheres

[0091]

[0092]

[0093] As can be seen from Table 2, compared with the groups of Comparative Example 2 and 3, Examples 6, 7 and Example 7 + lidocaine have basically the same facial improvement ratio, but there are cases of deterioration in Comparative Example 2 and 3. Considering the occurrence of adverse reactions, it may be related to the occurrence of injection site granuloma, material migration or bone fusion in the comparative examples.

[0094] Table 3 Clinical adverse reactions of hydroxyapatite core-shell microsphere-filled injections and untreated hydroxyapatite microspheres

[0095]

[0096] As can be seen from Table 3, 1) compared with Comparative Example 2, the incidence of adverse reactions in Examples 6 and 7 was significantly reduced, and no serious adverse reactions such as granuloma, material migration, and bone fusion occurred; 2) in the Example 7 + lidocaine group, compared with the single Example 7 group, the proportion of pain at the injection site was significantly lower, and there was no significant difference in other adverse reactions; 3) compared with the Comparative Example 3 group, the incidence of adverse reactions in the Example 7 + lidocaine group was significantly reduced, and no serious adverse reactions such as granuloma, material migration, and bone fusion occurred; 4) compared with the Comparative Example 3 group, in the Comparative Example 2, the pain rate at the injection site decreased, but the incidence of material migration and injection site inflammatory reaction was higher, which may be related to the delamination and rupture of the coating material and hydroxyapatite caused by the degradation of the drug in Comparative Example 3, resulting in debris and local irritation.

[0097] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A hydroxyapatite core microsphere for injection filling, characterized in that: The hydroxyapatite core microspheres are composed of hydroxyapatite and coating materials, and the particle size of the hydroxyapatite core microspheres is 25 to 60 μm; wherein, The amount of the hydroxyapatite microspheres is 70wt% to 95wt% of the total mass of the hydroxyapatite core microspheres, and the amount of the coating material is 5wt% to 30wt% of the total mass of the hydroxyapatite core microspheres.

2. The hydroxyapatite cored microspheres for injection filling according to claim 1, characterized in that: The coating material is selected from at least one of polylactic acid, polycaprolactone and polyacrylic acid resin.

3. The hydroxyapatite cored microspheres for injection filling according to claim 2, characterized in that: The polylactic acid is selected from at least one of poly-L-lactic acid, poly-D-lactic acid and poly-racemic lactic acid.

4. The hydroxyapatite cored microspheres for injection filling according to claim 1, characterized in that: The amount of the hydroxyapatite microspheres is 75wt% to 85wt% of the total mass of the hydroxyapatite core-coated microspheres.

5. The hydroxyapatite cored microspheres for injection filling according to claim 1, characterized in that: The amount of the coating material is 15wt% to 25wt% of the total mass of the hydroxyapatite core microspheres.

6. A method for preparing hydroxyapatite core microspheres for injection filling, characterized in that: The following steps are involved: (1) Weighing hydroxyapatite and coating material according to any one of claims 1 to 5; (2) dissolving the coating material in a solvent to obtain a coating material solution; (3) adding hydroxyapatite microspheres into a centrifugal granulation coating machine; (4) coating the coating material solution on the surface of hydroxyapatite at low temperature by centrifugal granulation coating to obtain hydroxyapatite core microspheres; (5) Screening the hydroxyapatite core microspheres to collect the hydroxyapatite core microspheres with a particle size of 25 μm to 60 μm.

7. The method for preparing hydroxyapatite core microspheres for injection filling according to claim 6, characterized in that: In step (2), the solvent is selected from at least one of dichloromethane, ethanol, isopropanol and acetone.

8. The method for preparing hydroxyapatite core microspheres for injection filling according to claim 6, characterized in that: In step (2), the mass concentration of the coating material is 5wt% to 20wt%.

9. The method for preparing hydroxyapatite core microspheres for injection filling according to claim 6, characterized in that: In step (4), the air inlet temperature of the centrifugal granulation coating machine is 5-15°C, and the atomization pressure is 3.0-4.0 bar.

Images