Polycaprolactone microspheres and interfacial membrane emulsification preparation method and application thereof

Abstract

The invention provides a polycaprolactone microsphere as well as an interfacial membrane emulsification preparation method and application thereof, and the interfacial membrane emulsification preparation method comprises the following steps: firstly, respectively preparing a dispersion phase containing polycaprolactone and a continuous phase containing a surfactant, and then centrifugally mixing the dispersion phase containing polycaprolactone and the continuous phase containing the surfactant in a planetary centrifugal emulsifying machine to form emulsion droplets; and finally, stirring the emulsion droplets to volatilize the organic solvent, washing with water, centrifuging and drying to obtain the polycaprolactone microspheres. The interfacial membrane emulsification preparation method is simple in process, convenient to operate and short in consumed time, and meanwhile, the prepared polycaprolactone microspheres are very uniform in particle size distribution, relatively narrow in particle size distribution, good in sphericity and good in application prospect, and the appearance of the polycaprolactone microspheres is of a spherical structure.

Description

Technical Field

[0001] The invention belongs to the technical field of microspheres, and in particular relates to a polycaprolactone microsphere and a limiting membrane emulsification preparation method and application thereof. Background Art

[0002] Drug-loaded microspheres are a new drug delivery technology developed at the end of the 20th century. They are generally 1 to 250 μm in diameter and refer to a microparticle dispersion system formed by dispersing or adsorbing drugs in a macromolecular or polymer matrix. There are many carrier materials used to prepare drug-loaded microspheres, which are mainly divided into natural polymer carrier materials (such as starch, albumin, gelatin and chitosan, etc.) and synthetic polymer carrier materials (such as polylactic acid, etc.).

[0003] Polycaprolactone (PCL) is a synthetic polyester biopolymer material that is biodegradable and biocompatible. It is a hydrophobic polymer with a long-term degradation mechanism. Its final degradation products will be absorbed and excreted from the body. It has been widely used in the control system of sustained-release microspheres.

[0004] At present, the conventional preparation methods of polycaprolactone microspheres mainly include spray drying, high-speed stirring and shearing, and membrane emulsification. Among them, the polycaprolactone microspheres prepared by spray drying and high-speed stirring and shearing are of uneven sizes and wide particle size distribution, and there is a greater risk of needle clogging during injection filling. When preparing microspheres by the high-speed stirring and shearing method, the stirring or shearing equipment easily mixes the oil and water phases at a faster speed, forming turbulence between the two phases, which greatly affects the uniformity of the particle size of the microspheres. The injection application of the prepared microspheres in the subcutaneous or tissue gaps also has the risk of needle clogging or particle accumulation.

[0005] At the same time, the particle size of the polycaprolactone microspheres prepared by the membrane emulsification method is uniform, which eliminates the need for screening and subsequent screen cleaning and regeneration processing, simplifies the overall process, and significantly reduces the process cost of uniform microsphere production. For example, CN116078298A discloses a polycaprolactone microsphere and its membrane emulsification preparation method, application, and filler, including the following steps: using a polycaprolactone solution as a dispersed phase, using a pressure of 1 to 13 kPa to press the dispersed phase through the membrane pores of the membrane tube, forming polycaprolactone droplets in the continuous phase, and the continuous phase carries the polycaprolactone droplets away; wherein the concentration of polycaprolactone in the dispersed phase is 0.04 to 0.15 mg / mL, and the molecular weight of polycaprolactone is 0.5 to 15,000 Daltons; collecting the mixed solution of the polycaprolactone droplets and the continuous phase, and then at a rate of 100 to 400 rpm The mixture is stirred to form polycaprolactone microspheres. The preparation method can effectively prepare polycaprolactone microspheres with good roundness and basically no fragments. However, the preparation method provided by the invention is time-consuming and generally requires several hours to dozens of hours to complete the membrane emulsification process. The reason is that the membrane emulsification method requires the oil phase system with higher viscosity to be extruded through a membrane to form relatively uniform droplets, thereby preparing microspheres with relatively uniform particle size. Therefore, this method is difficult to meet the needs of large-scale production due to its slow membrane passing speed, and the production capacity reserve of the process is easily limited by its preparation principle.

[0006] Therefore, in view of the above problems, it is urgent to develop a preparation method for polycaprolactone microspheres which is time-saving, has mild process conditions and can produce polycaprolactone microspheres with uniform particle size and high sphericity. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a polycaprolactone microsphere and a limiting membrane emulsification preparation method and application thereof. The limiting membrane emulsification preparation method is not only simple in process, convenient in operation, and short in time, but also the prepared polycaprolactone microspheres have a very uniform particle size distribution, a narrow particle size distribution, a spherical structure in appearance, good sphericity, and good application prospects.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing polycaprolactone microspheres by emulsification of the limiting membrane, the method comprising the following steps:

[0010] (1) dissolving polycaprolactone in an organic solvent to obtain a dispersed phase; dissolving a surfactant in water to obtain a continuous phase;

[0011] (2) centrifugally mixing the dispersed phase and the continuous phase obtained in step (1) in a planetary centrifugal emulsifier to obtain emulsion droplets;

[0012] (3) The emulsion obtained in step (2) is stirred to volatilize the organic solvent, washed with water, centrifuged and dried to obtain the polycaprolactone microspheres.

[0013] The preparation method of the polycaprolactone microspheres provided by the present invention adopts an interfacial film emulsification method, which is still a technology based on the volatilization of the emulsification solvent.

[0014] First, it is necessary to prepare a dispersed phase containing polycaprolactone and a continuous phase containing a surfactant respectively, and then the two are centrifugally mixed in a planetary centrifugal emulsifier. When the planetary centrifugal emulsifier is used for centrifugal mixing, centrifugal revolution and centrifugal rotation are performed simultaneously. The centrifugal revolution enables the continuous phase and the dispersed phase to form a stable oil-water boundary film with the help of centrifugal force, thereby increasing the mixing area. The centrifugal rotation will generate a certain linear velocity. Due to the different properties and specific gravities of the continuous phase and the dispersed phase, the linear velocities generated by the two are different. During the centrifugal rotation, the linear velocity of the continuous phase and the dispersed phase is different. In this case, the two phases are in a transition state between turbulence and laminar flow, which will produce a strong vortex fluidity and form a centrifugal vector synthetic force, so that the shear force between the material and the wall and the molecules inside the material produce a mutual dispersion effect, so that the two phases can be fully mixed and sheared to form O / W type emulsion droplets loaded with polycaprolactone; finally, the O / W type emulsion droplets are stirred to evaporate the organic solvent contained therein, and the O / W type emulsion droplets will gradually solidify into microspheres, and the microspheres are collected by washing with water and centrifuging, and the collected microspheres are dried to obtain the polycaprolactone microspheres.

[0015] In summary, the limiting membrane emulsification preparation method provided by the present invention not only has the advantages of simple process, convenient operation and short time consumption, but also the process can make the prepared polycaprolactone microspheres very evenly distributed due to the mild and controllable shear effect, with a narrow particle size distribution and a spherical structure in appearance, good sphericity, and has a good application prospect.

[0016] Preferably, the intrinsic viscosity (IV) of the polycaprolactone in step (1) is 0.1 to 3 dl / g, for example, 0.1 dl / g, 0.2 dl / g, 0.5 dl / g, 1 dl / g, 1.5 dl / g, 2 dl / g, 2.5 dl / g or 3 dl / g.

[0017] Preferably, the polycaprolactone in step (1) includes any one of polycaprolactone IV0.1-0.5 (PCL IV0.1-0.5), polycaprolactone IV0.5-1.0 (PCL IV0.5-1.0), polycaprolactone IV1.0-1.5 (PCL IV1.0-1.5), polycaprolactone IV1.5-2.0 (PCL IV1.5-2.0) or polycaprolactone IV2.0-3.0 (PCL IV2.0-3.0).

[0018] Preferably, the organic solvent in step (1) comprises any one of dichloromethane, chloroform or acetone, or a combination of at least two thereof.

[0019] Preferably, the mass percentage of polycaprolactone in the dispersed phase of step (1) is 5-20%, for example, 5%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc.

[0020] Preferably, the surfactant in step (1) comprises polyvinyl alcohol and / or methyl cellulose, more preferably polyvinyl alcohol.

[0021] Preferably, the polyvinyl alcohol includes any one of polyvinyl alcohol 0388, polyvinyl alcohol 0588, polyvinyl alcohol 1788, polyvinyl alcohol 2488 or polyvinyl alcohol 403, or a combination of at least two thereof.

[0022] Preferably, the methylcellulose includes any one of methylcellulose MC 55RT400, methylcellulose MC 55RT40000 or methylcellulose MC 55RT70000, or a combination of at least two thereof.

[0023] Preferably, the mass percentage of the surfactant in the continuous phase of step (1) is 0.8-1.5%, for example 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4% or 1.5%, etc.

[0024] Preferably, the mass ratio of the dispersed phase to the continuous phase in step (2) is 1:(3-10), for example 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, etc.

[0025] Preferably, the orbital speed of the planetary centrifugal emulsifier in step (2) is 600-1500 rpm, for example, 600 rpm, 700 rpm, 800 rpm, 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm, 1300 rpm, 1400 rpm or 1500 rpm.

[0026] Preferably, the rotation speed of the planetary centrifugal emulsifier in step (2) is 40-80% of the orbital speed, for example, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%.

[0027] Preferably, the rotation speed of the planetary centrifugal emulsifier in step (2) is 240 to 1200 rpm, for example, 240 rpm, 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm, 1000 rpm or 1200 rpm.

[0028] Preferably, the temperature of the centrifugal mixing in step (2) is 25-45°C, for example, 25°C, 27°C, 29°C, 31°C, 33°C, 35°C, 37°C, 39°C, 41°C, 43°C or 45°C, etc.

[0029] Preferably, the centrifugal mixing time in step (2) is 3 to 6 minutes, for example, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes, 5 minutes, 5.5 minutes or 6 minutes.

[0030] Preferably, the stirring in step (3) is carried out at a rotation speed of 400 to 1000 rpm (for example, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm or 1000 rpm, etc.).

[0031] Preferably, the stirring temperature in step (3) is 25-40°C, for example, 25°C, 27°C, 29°C, 31°C, 33°C, 35°C, 37°C, 39°C or 40°C.

[0032] Preferably, the stirring time in step (3) is 1 to 3 h, for example, 1 h, 1.2 h, 1.4 h, 1.6 h, 1.8 h, 2 h, 2.2 h, 2.4 h, 2.6 h, 2.8 h or 3 h.

[0033] Preferably, the rotation speed of the water washing centrifugation in step (3) is 10000-15000 rpm (for example, 10000 rpm, 10500 rpm, 11000 rpm, 11500 rpm, 12000 rpm, 12500 rpm, 13000 rpm, 13500 rpm, 14000 rpm, 14500 rpm or 15000 rpm, etc.).

[0034] Preferably, the drying in step (3) is freeze drying and / or vacuum drying.

[0035] As a preferred technical solution of the present invention, the limiting membrane emulsification preparation method comprises the following steps:

[0036] (1) dissolving polycaprolactone in an organic solvent to obtain a dispersed phase with a mass percentage of polycaprolactone of 5 to 20%; dissolving a surfactant in water, heating to 70 to 80° C., and cooling to room temperature to obtain a continuous phase with a mass percentage of polycaprolactone of 0.8 to 1.5%;

[0037] (2) placing the dispersed phase and the continuous phase in a mass ratio of 1:(3-10) in a planetary centrifugal emulsifier, centrifugally mixing for 3-6 minutes at an orbital speed of 600-1500 rpm, an autorotational speed of 240-1200 rpm and a temperature of 25-45° C. to form O / W type emulsion droplets;

[0038] (3) stirring the O / W emulsion droplets at 400-1000 rpm and 25-40° C. for 1-3 h to volatilize the organic solvent, washing and centrifuging the emulsion droplets several times, removing the supernatant, and finally drying the emulsion droplets to obtain the polycaprolactone microspheres.

[0039] In a second aspect, the present invention provides polycaprolactone microspheres, which are prepared by the limiting membrane emulsification preparation method as described in the first aspect.

[0040] Preferably, the average particle size of the polycaprolactone microspheres is 25 to 50 μm, such as 25 μm, 30 μm, 40 μm or 50 μm.

[0041] Preferably, the particle size distribution coefficient (Span) of the polycaprolactone microspheres is ≤0.8, such as 0.7, 0.6, 0.5, 0.4, 0.3 or 0.2.

[0042] Preferably, the sphericity of the polycaprolactone microspheres is ≥0.95, for example, 0.96, 0.97, 0.975, 0.98, 0.985, 0.99 or 0.995, etc.

[0043] In a third aspect, the present invention provides an application of the polycaprolactone microspheres as described in the first aspect, wherein the application comprises mixing the polycaprolactone microspheres with gel and then filling the mixture into a syringe to prepare a microsphere gel injection.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The invention provides a method for preparing polycaprolactone microspheres by boundary membrane emulsification, wherein a dispersed phase containing polycaprolactone and a continuous phase containing a surfactant are first prepared respectively, and then the two are centrifugally mixed in a planetary centrifugal emulsifier to form an emulsion, and finally the emulsion droplets are stirred to volatilize an organic solvent to realize microsphere solidification, and the microspheres are washed, centrifuged and dried to obtain the polycaprolactone microspheres. The method for preparing polycaprolactone microspheres by boundary membrane emulsification has the advantages of simple process, convenient operation and short time consumption, and can make the prepared polycaprolactone microspheres very evenly distributed, narrow in particle size distribution, and all present a spherical structure in appearance, with good sphericity, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is an optical microscope image of the O / W type emulsion droplets obtained in step (2) of Example 3;

[0047] Figure 2 This is a scanning electron microscope image of the polycaprolactone microspheres obtained in Example 3;

[0048] Figure 3 This is a scanning electron microscope image of the polycaprolactone microspheres obtained in Comparative Example 1;

[0049] Figure 4 This is a scanning electron microscope image of the polycaprolactone microspheres obtained in Comparative Example 2. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0051] Unless otherwise specified, the raw materials involved in the following specific embodiments are all conventional materials in the art and can be purchased commercially. In particular, the information of some raw materials and instruments involved in the following examples and comparative examples is as follows:

[0052] (1) Raw materials

[0053] Polycaprolactone A: IV is 0.48 dl / g, Mn is 38000, purchased from Jinan Daigang Bioengineering Co., Ltd., China;

[0054] Polycaprolactone B: IV is 0.84 dl / g, Mn is 40000, purchased from Lactel, USA;

[0055] Dichloromethane: purchased from Guangzhou Xilong Science Co., Ltd.;

[0056] Polyvinyl alcohol 1788: purchased from Jiangxi Alpha Hi-Tech Pharmaceutical Co., Ltd.;

[0057] Methylcellulose MC 55RT400: purchased from Taian Ruitai Cellulose Co., Ltd.

[0058] (2) Instruments:

[0059] Planetary centrifugal emulsifier: ATS Nanotechnology (Suzhou) Co., Ltd.

[0060] Electronic balance: Sartorius Scientific Instruments (Beijing) Co., Ltd., model GL124-1SCN;

[0061] Laser particle size analyzer: Zhuhai OMEC Instrument Co., Ltd., model: Topsizer Plus;

[0062] Magnetic stirrer: Changzhou Su Rui Instrument Co., Ltd., model HJ-6B;

[0063] Vortex instrument: Jintan Baita Xinbao Instrument Factory, model XH-C;

[0064] High-speed refrigerated centrifuge: Shanghai Luxiangyi Centrifuge Instrument Co., Ltd., model TGL-20M;

[0065] Thermal field emission scanning electron microscope: JEOL Ltd., model JSM-7001F;

[0066] Freeze dryer: Shanghai Bilang Instrument Manufacturing Co., Ltd., model FD-1A-80;

[0067] Optical microscope: Nanjing Jiangnan Yongxin Optics Co., Ltd., model BM2000.

[0068] Example 1

[0069] A method for preparing polycaprolactone microspheres by emulsification of the limiting membrane comprises the following steps:

[0070] (1) Using an electronic balance, 1 g of polycaprolactone A was accurately weighed and placed in a 50 mL centrifuge tube, and then 9 g of dichloromethane was added to the centrifuge tube, and vortexed to completely dissolve the mixture, thereby obtaining a dispersed phase having a polycaprolactone content of 10% by weight;

[0071] 0.9 g of polyvinyl alcohol 1788 was accurately weighed with an electronic balance and dissolved in 98.1 g of purified water. The mixture was heated to 85° C. with a heating magnetic stirrer to fully dissolve the mixture. The mixture was then cooled to room temperature to obtain a continuous phase having a mass percentage of 1% polyvinyl alcohol.

[0072] (2) 90 g of the continuous phase was poured into the container box, and then 10 g of the dispersed phase was slowly poured into the container box along the wall, and then the container box was placed in a planetary membrane emulsifier, and centrifuged for 5 min at an orbital speed of 1000 rpm, a rotational speed of 800 rpm, and a temperature of 30° C. to form O / W type emulsion droplets;

[0073] (3) The O / W type emulsion droplets were taken out, stirred and evaporated at 25°C and 600 rpm for 3 h to remove dichloromethane, and then placed in a high-speed refrigerated centrifuge, centrifuged at 10,000 rpm for 10 min, and then washed and centrifuged at 10,000 rpm for 3 times, each time for 10 min. After removing the supernatant, the emulsion was placed in a freeze dryer, pre-frozen at -80°C for 2 h, and freeze-dried for 24 h to obtain the polycaprolactone microspheres.

[0074] Example 2

[0075] A method for preparing polycaprolactone microspheres by emulsification of the limiting membrane comprises the following steps:

[0076] (1) Using an electronic balance, 1.5 g of polycaprolactone B was accurately weighed and placed in a 50 mL centrifuge tube. Then, 8.5 g of dichloromethane was added to the centrifuge tube and vortexed to completely dissolve the polycaprolactone to obtain a dispersed phase having a mass percentage of 15%;

[0077] 1.5 g of polyvinyl alcohol 1788 was accurately weighed with an electronic balance and dissolved in 98.5 g of purified water. The mixture was heated to 70° C. with a heating magnetic stirrer to fully dissolve the mixture. The mixture was then cooled to room temperature to obtain a continuous phase having a mass percentage of polyvinyl alcohol of 1.5%.

[0078] (2) Pour 50 g of the continuous phase into the container box, then slowly pour 10 g of the dispersed phase into the container box along the wall, and then place the container box into a planetary membrane emulsifier, centrifuge and mix for 3 min at an orbital speed of 800 rpm, an autorotational speed of 600 rpm, and a temperature of 40° C. to form O / W type emulsion droplets;

[0079] (3) The O / W emulsion droplets were taken out, stirred and evaporated at 25° C. and 600 rpm for 3 h to remove dichloromethane, and placed in a high-speed refrigerated centrifuge after stirring, centrifuged at 10,000 rpm for 10 min, and then washed and centrifuged at 10,000 rpm for 3 times, each time for 10 min. After the end, the supernatant was removed and finally placed in a freeze dryer, pre-frozen at -80° C. for 2 h, and freeze-dried for 24 h to obtain the polycaprolactone microspheres.

[0080] Example 3

[0081] A method for preparing polycaprolactone microspheres by centrifugal limiting membrane emulsification specifically comprises the following steps:

[0082] (1) Using an electronic balance, 2 g of polycaprolactone A is accurately weighed and placed in a 50 mL centrifuge tube, and then 18 g of dichloromethane is added to the centrifuge tube, and vortexed to completely dissolve the mixture, thereby obtaining a dispersed phase having a polycaprolactone content of 10% by weight;

[0083] 0.8 g of polyvinyl alcohol 1788 was accurately weighed with an electronic balance and dissolved in 79.2 g of purified water. The mixture was heated to 80° C. with a heating magnetic stirrer to fully dissolve the mixture. The mixture was then cooled to room temperature to obtain a continuous phase having a mass percentage of 1% polyvinyl alcohol.

[0084] (2) 80 g of the continuous phase was poured into the container box, and then 20 g of the dispersed phase was slowly poured into the container box along the wall, and then the container box was placed in a planetary membrane emulsifier, and centrifuged and mixed for 3 min at an orbital speed of 800 rpm, an autorotational speed of 480 rpm, and a temperature of 25° C. to form O / W type emulsion droplets;

[0085] (3) The O / W emulsion droplets were taken out, stirred and evaporated at 25°C and 800 rpm for 3 hours to remove dichloromethane, and placed in a high-speed refrigerated centrifuge after stirring, centrifuged at 10,000 rpm for 10 minutes, and then washed and centrifuged at 10,000 rpm for 3 times, each time for 10 minutes, and finally placed in a freeze dryer, pre-frozen at -80°C for 2 hours, and freeze-dried for 24 hours to obtain the polycaprolactone microspheres.

[0086] Example 4

[0087] A method for preparing polycaprolactone microspheres by centrifugal membrane emulsification, which differs from Example 3 in that the orbital speed of the planetary membrane emulsifier in step (2) is 1000 rpm and the rotational speed is 600 rpm, and other substances, amounts and steps are the same as those in Example 3.

[0088] Example 5

[0089] A method for preparing polycaprolactone microspheres by centrifugal membrane emulsification, which differs from Example 3 in that the orbital speed of the planetary membrane emulsifier in step (2) is 1200 rpm and the rotational speed is 720 rpm, and other substances, amounts and steps are the same as those in Example 3.

[0090] Example 6

[0091] A method for preparing polycaprolactone microspheres by centrifugal membrane emulsification, which differs from Example 3 in that the orbital speed of the planetary membrane emulsifier in step (2) is 1500 rpm and the rotational speed is 900 rpm, and other substances, amounts and steps are the same as those in Example 3.

[0092] Example 7

[0093] A method for preparing polycaprolactone microspheres by centrifugal membrane emulsification, which differs from Example 3 in that the orbital speed of the planetary membrane emulsifier in step (2) is 1800 rpm and the rotational speed is 1080 rpm, and other substances, amounts and steps are the same as those in Example 3.

[0094] Example 8

[0095] A method for preparing polycaprolactone microspheres by emulsification of a limiting membrane, which differs from Example 3 in that the orbital speed of the planetary limiting membrane emulsifier in step (2) is 500 rpm and the rotational speed is 300 rpm, and other substances, amounts and steps are the same as those in Example 3.

[0096] Example 9

[0097] A method for preparing polycaprolactone microspheres by emulsification of a limiting membrane, which differs from Example 3 in that the amount of the continuous phase in step (2) is 50 g, and the other substances, amounts and steps are the same as those in Example 3.

[0098] Example 10

[0099] A method for preparing polycaprolactone microspheres by centrifugal limiting membrane emulsification is disclosed. The method is different from Example 3 in that the amount of dispersed phase used in step (2) is 6 g, and other substances, amounts and steps are the same as those in Example 3.

[0100] Embodiment 11

[0101] A method for preparing polycaprolactone microspheres by centrifugal limiting membrane emulsification is disclosed. The method differs from Example 3 in that methylcellulose MC 55RT400 is used to replace polyvinyl alcohol 1788, and other substances, amounts and steps are the same as those in Example 3.

[0102] Comparative Example 1

[0103] A high-speed stirring and shearing emulsification preparation method for polycaprolactone microspheres specifically comprises: weighing 1g of polycaprolactone and dissolving it in 10mL of dichloromethane solvent, adding 1mL of purified water containing 2% PVA1788 and vortexing for 5min, adding 100mL of purified water containing 0.2% PVA1788, shearing at 14000rpm for 3min, continuing to stir at 1500rpm for 3h, centrifuging at 15000rpm for 10min after the stirring is completed, discarding the supernatant, adding purified water to wash the microspheres and centrifuging at 15000rpm for 10min, repeating the washing three times and freeze-drying to obtain the polycaprolactone microspheres.

[0104] Comparative Example 2

[0105] A membrane emulsification preparation method for polycaprolactone microspheres specifically comprises: weighing 1g of polycaprolactone and placing it in a 50mL centrifuge tube, then adding dichloromethane to the centrifuge tube until 5g is added, placing a membrane emulsification device in a 50g continuous phase solution containing 1% PVA, passing a prepared 20% PCL dichloromethane solution through the membrane emulsification device at a pressure of about 1500mPa, continuously extruding for about 1h until all dispersed phases are completely extruded, taking out the emulsion and continuing to stir and volatilize for 3h, centrifuging at 1000rpm for 10min, pouring out the supernatant, then washing and centrifuging at 10000rpm for 3 times, each time for 10min, finally pre-freezing at -80°C for 2h, freeze-drying for 24h, to obtain the polycaprolactone microspheres.

[0106] Performance Test:

[0107] (1) Optical microscope test: The O / W type emulsion droplets obtained in step (2) of Example 3 were first tested using an optical microscope, and an optical microscope image of the O / W type emulsion droplets obtained in step (2) of Example 3 was obtained as shown in FIG. Figure 1 As shown, Figure 1 In the figure, the smallest unit of the scale is 10 μm;

[0108] from Figure 1 It can be seen that in the method for preparing polycaprolactone microspheres by limiting membrane emulsification provided in Example 3, the particles in the formed O / W type emulsion droplets have good uniformity and high roundness, and the diameter of the microspheres before solidification and drying is 30 to 60 μm.

[0109] (2) Scanning electron microscope test: The polycaprolactone microspheres obtained in Example 3 and Comparative Examples 1-2 were tested using a thermal field emission scanning electron microscope. The scanning electron microscope images of the polycaprolactone microspheres obtained in Example 3 and Comparative Examples 1-2 were as follows: Figure 2 to Figure 4 As shown;

[0110] from Figure 2 to Figure 4 It can be seen from the comparison that the particle size distribution of the polycaprolactone microspheres provided in Example 3 is 25-50 μm, and the roundness is high and the distribution is uniform; while the polycaprolactone microspheres provided in Comparative Examples 1-2 have a low roundness, uneven distribution, and poor particle size uniformity.

[0111] (3) Average particle size: The test was performed using a laser particle size analyzer. Specifically, the polycaprolactone microspheres were evenly dispersed in distilled water by ultrasonication to obtain a suspension, the suspension was slowly dripped into a sample tank using a dropper, and the laser particle size analyzer automatically sucked the suspension into the laser channel, and the average particle size was automatically measured under the set program.

[0112] (4) Span value of particle size distribution coefficient: Particle size distribution can be expressed by span value. The smaller the span value, the narrower the particle size distribution, that is, the more uniform the particle size. The particle size distribution span is shown in the following formula:

[0113]

[0114] Among them, D N％ (N = 10, 50 and 90) are the particle sizes of the microspheres D N％ The volume fraction when it is N%.

[0115] (5) Sphericity: 50 or more microspheres were selected from the SEM images. The sphericity of the microspheres was determined by the shortest diameter (D iL ) and the longest diameter (D iS ), the specific formula is as follows:

[0116]

[0117] In the formula, S B is the sphericity (%), D iL , D iS are the longest diameter and shortest diameter of a microsphere (μm), respectively, and n is the number of microspheres (pieces);

[0118] (6) Yield: Calculated based on the amount of polycaprolactone input and the weight of microspheres in the range of 25 to 50 μm, i.e., weight of microspheres in the range of 25 to 50 μm / amount of polycaprolactone input×100%.

[0119] The polycaprolactone microspheres provided in Examples 1 to 11 and Comparative Examples 1 to 2 were tested according to the above test method. The test results are shown in Table 1:

[0120] Table 1

[0121]

[0122]

[0123] From the data in Table 1, we can see that:

[0124] Under preferred conditions, the limiting membrane emulsification preparation method provided in Examples 1 to 6 can prepare polycaprolactone microspheres with an average particle size of 25 to 50 μm, a sphericity of not less than 0.95 and a high yield. By comparing the data of Example 3 and Examples 7 to 11, it can be found that the concentration of PVA, the centrifugal speed, etc. can affect the formation of polycaprolactone microspheres.

[0125] In addition, compared with the limiting membrane emulsification preparation method provided by the present invention, the polycaprolactone microspheres prepared by the conventional high-speed stirring shear emulsification method provided in Comparative Example 1 are unevenly distributed and have poor sphericity; while the conventional membrane emulsification method provided in Comparative Example 2 is time-consuming and the microsphere sphericity, average particle size and other indicators are not as good as the limiting membrane emulsification process.

[0126] The applicant declares that the present invention illustrates a polycaprolactone microsphere and its centrifugal membrane emulsification preparation method and application through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing polycaprolactone microspheres by emulsification of the limiting membrane, characterized in that: The limiting membrane emulsification preparation method comprises the following steps: (1) dissolving polycaprolactone in an organic solvent to obtain a dispersed phase; dissolving a surfactant in water to obtain a continuous phase; (2) centrifugally mixing the dispersed phase and the continuous phase obtained in step (1) in a planetary centrifugal emulsifier to obtain emulsion droplets; (3) The emulsion obtained in step (2) is stirred to volatilize the organic solvent, washed with water, centrifuged and dried to obtain the polycaprolactone microspheres.

2. The method for preparing the limiting membrane emulsification according to claim 1, characterized in that: The intrinsic viscosity of the polycaprolactone in step (1) is 0.1 to 3 dl / g; Preferably, the organic solvent in step (1) comprises any one of dichloromethane, chloroform or acetone, or a combination of at least two thereof; Preferably, the mass percentage of polycaprolactone in the dispersed phase in step (1) is 5-20%.

3. The method for preparing the limiting membrane emulsification according to claim 1 or 2, characterized in that: The surfactant in step (1) comprises polyvinyl alcohol and / or methyl cellulose, preferably polyvinyl alcohol; Preferably, the polyvinyl alcohol includes any one of polyvinyl alcohol 0388, polyvinyl alcohol 0588, polyvinyl alcohol 1788, polyvinyl alcohol 2488 or polyvinyl alcohol 403, or a combination of at least two thereof; Preferably, the methylcellulose comprises any one of methylcellulose MC 55RT400, methylcellulose MC 55RT40000 or methylcellulose MC 55RT70000, or a combination of at least two thereof; Preferably, the mass percentage of the surfactant in the continuous phase in step (1) is 0.8-1.5%.

4. The limiting membrane emulsification preparation method according to any one of claims 1 to 3, characterized in that: The mass ratio of the dispersed phase to the continuous phase in step (2) is 1:(3-10).

5. The limiting membrane emulsification preparation method according to any one of claims 1 to 4, characterized in that: The planetary centrifugal emulsifier in step (2) has an orbital speed of 600 to 1500 rpm; Preferably, the rotation speed of the planetary centrifugal emulsifier in step (2) is 40 to 80% of the revolution speed; Preferably, the rotation speed of the planetary centrifugal emulsifier in step (2) is 240 to 1200 rpm; Preferably, the temperature of the centrifugal mixing in step (2) is 25 to 45°C; Preferably, the centrifugal mixing time in step (2) is 3 to 6 minutes.

6. The limiting membrane emulsification preparation method according to any one of claims 1 to 5, characterized in that: The stirring in step (3) is carried out at a rotation speed of 400 to 1000 rpm; Preferably, the stirring temperature in step (3) is 25 to 40° C. Preferably, the stirring time in step (3) is 1 to 3 hours.

7. The limiting membrane emulsification preparation method according to any one of claims 1 to 6, characterized in that: The rotation speed of the water washing centrifuge in step (3) is 10000-15000 rpm; Preferably, the drying in step (3) is freeze drying and / or vacuum drying.

8. The method for preparing polycaprolactone microspheres by limiting membrane emulsification according to any one of claims 1 to 7, characterized in that: The limiting membrane emulsification preparation method comprises the following steps: (1) dissolving polycaprolactone in an organic solvent to obtain a dispersed phase with a mass percentage of polycaprolactone of 5 to 20%; dissolving a surfactant in water, heating to 70 to 80° C., and cooling to room temperature to obtain a continuous phase with a mass percentage of polycaprolactone of 0.8 to 1.5%; (2) placing the dispersed phase and the continuous phase in a mass ratio of 1:(3-10) into a planetary centrifugal emulsifier, centrifugally mixing for 3-6 minutes at an orbital speed of 600-1500 rpm, an autorotational speed of 240-1200 rpm and a temperature of 25-45° C. to form O / W type emulsion droplets; (3) stirring the O / W emulsion droplets at 400-1000 rpm and 25-40° C. for 1-3 h to volatilize the organic solvent, washing and centrifuging the emulsion droplets several times, removing the supernatant, and drying the emulsion droplets to obtain the polycaprolactone microspheres.

9. A polycaprolactone microsphere, characterized in that: The polycaprolactone microspheres are prepared by the limiting membrane emulsification preparation method according to any one of claims 1 to 8; Preferably, the average particle size of the polycaprolactone microspheres is 25 to 50 μm; Preferably, the Span value of the polycaprolactone microspheres is ≤0.8; Preferably, the polycaprolactone microspheres have a sphericity of ≥0.

95.

10. A use of the polycaprolactone microspheres as claimed in claim 9, characterized in that: The application comprises mixing the polycaprolactone microspheres with gel and then filling the mixture into a syringe to prepare a microsphere gel injection.

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