Method for preparing biodegradable polymer microparticles, biodegradable polymer microparticles, and composition for tissue repair

Abstract

The present invention provides a method for preparing biodegradable polymer microparticles having an active ingredient loaded thereon, the method comprising: (A) a covalently bonded product formation step of forming a covalently bonded product by linking the active ingredient to the biodegradable polymer through a covalent bond; (B) a microparticle dispersing step of dispersing the covalently bonded product in a solvent to form dispersed microparticles in a solution; and (C) a microparticle separation step of separating the microparticles from the solution. The present invention has an advantage of effectively preparing biodegradable polymer microparticles to enable delayed release of an active ingredient.

Description

Method for producing biodegradable polymer microparticles, biodegradable polymer microparticles, and composition for tissue repair

[0001] The present invention relates to a method for producing biodegradable polymer microparticles that can be used for tissue repair, biodegradable polymer microparticles, and a composition for tissue repair, and more specifically, to a method for producing biodegradable polymer microparticles loaded with an effective ingredient, biodegradable polymer microparticles, and a composition for tissue repair, which can produce biodegradable polymer microparticles by loading an effective ingredient so that the effective ingredient is released more effectively and exerts an effect.

[0002] Biodegradable materials for tissue repair, such as plastic prosthetics (e.g., fillers) and bone fillers, are not solely composed of biodegradable polymers; they often contain additional active ingredients, such as vitamins. For example, microspheres encapsulating active ingredients such as L-ascorbic acid have been developed (see Korean Patent No. 10-2034871). While this technology could potentially promote the action of active ingredients during tissue repair, the relatively early release of active ingredients simply encapsulated within the microspheres presents a limitation, making it difficult to expect sustained and adequate effects.

[0003] [Prior Art Literature]

[0004] [Patent Document]

[0005] (Patent Document 1) Republic of Korea Patent Publication No. 10-2034871, November 8, 2019, Specification

[0006] One problem that the present invention seeks to solve is to provide a method for manufacturing biodegradable polymer microparticles loaded with an effective ingredient, which can manufacture biodegradable polymer microparticles by loading an effective ingredient therein so that the effective ingredient is released more effectively and exerts an effect.

[0007] In addition, another problem that the present invention seeks to solve is to provide biodegradable polymer microparticles loaded with an active ingredient so that the active ingredient can be released more effectively.

[0008] In addition, another problem that the present invention seeks to solve is to provide a tissue repair composition comprising biodegradable polymer microparticles loaded with an effective ingredient so that the effective ingredient can be released more effectively.

[0009] The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0010] The present invention provides a method for producing biodegradable polymer microparticles loaded with an active ingredient, comprising: (A) a covalent bond forming step of covalently linking the active ingredient to the biodegradable polymer to form a covalent bond; (B) a microparticle dispersing step of dispersing the covalent bond in a solvent to form microparticles dispersed in a solution; and (C) a microparticle separation step of separating the microparticles from the solution.

[0011] The biodegradable polymer is polylactic acid, and the solution comprises 0.5 to 1.5 wt% of the covalent bond, 1.5 to 2.5 wt% of an emulsifier, and 2.5 to 4.0 wt% of a stabilizer, wherein the covalent bond may have an effective ingredient release amount of 50% or less for up to 150 days and 80% or more for up to 210 days.

[0012] In addition, the present invention provides biodegradable polymer microparticles loaded with an effective ingredient manufactured by the manufacturing method of the present invention.

[0013] In addition, the present invention provides a tissue repair composition comprising the biodegradable polymer microparticles of the present invention.

[0014] The present invention can effectively manufacture biodegradable polymer microparticles that enable the delayed release of an active ingredient. Furthermore, the biodegradable polymer microparticles or tissue repair compositions of the present invention can more effectively release the active ingredient. Therefore, because the present invention enables the effective release of the active ingredient, the duration of its effect on tissue repair can also be controlled.

[0015] Figure 1 is a flowchart for explaining one embodiment of the present invention.

[0016] Figure 2 is a graph of NMR analysis (covalent compound / CDCl3) performed in Experimental Example 1.

[0017] Figure 3 is a graph of NMR analysis (biodegradable polymer / CDCl3) performed in Experimental Example 1.

[0018] Figure 4 is a graph of NMR analysis (active ingredient / D2O) performed in Experimental Example 1.

[0019] Figure 5 is a graph of NMR analysis (covalent bond / D2O) performed in Experimental Example 1.

[0020] Figure 6 is a graph showing the polymer decomposition characteristics in Experimental Example 2.

[0021] Figure 7 is a graph showing the release characteristics of the active ingredient in Experimental Example 2.

[0022] The advantages and features of the present invention, as well as the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined solely by the claims.

[0023] Hereinafter, a method for manufacturing biodegradable polymer microparticles loaded with an effective ingredient, which is an embodiment of the present invention, will be described in more detail with reference to FIG. 1.

[0024] Figure 1 is a flowchart illustrating one embodiment of the present invention. As illustrated in Figure 1, a method for manufacturing biodegradable polymer microparticles loaded with an active ingredient, which is one embodiment of the present invention, comprises (A) a covalent bond formation step; (B) a microparticle dispersion step; and (C) a microparticle separation step.

[0025] Step (A) is the step of forming a covalent bond by covalently linking the active ingredient with the biodegradable polymer. In this step, by forming the covalent bond, the active ingredient is strongly bound to the biodegradable polymer to form microparticles. As a result, the release of the active ingredient can be delayed and appropriately released. This is also confirmed by experimental examples. That is, as also confirmed by experimental examples, the covalent bond not only delays the release of the active ingredient for a long period of time, but also enables the effective release of the active ingredient after a certain period of time.

[0026] For example, the covalent bond may have an effective ingredient release rate of 50% or less for up to 150 days. In addition, the covalent bond may have an effective ingredient release rate of 80% or more for up to 210 days. In this way, not only can the release of the effective ingredient be delayed for a long period of time, but unnecessary residue after a certain period of time can be avoided. The covalent bond may have a period in which the effective ingredient release rate is faster than the biodegradable polymer decomposition rate. For example, the period may be a period from 100 days to 150 days under a temperature condition of 36 degrees Celsius in phosphate buffered saline. In this way, since the effective ingredient is released faster than the biodegradable polymer decomposition rate, the effective ingredient can continue to act while the biodegradable polymer maintains its tissue repair function.

[0027] Active ingredients are substances that can exhibit effects depending on their activity during the tissue repair process. These effects may include, for example, skin whitening or wrinkle improvement.

[0028] Active ingredients include, but are not limited to, hydroquinone, arbutin, vitamins or derivatives or salts thereof, magnesium ascorbylphosphate, calcium ascorbylphosphate, ascorbic acid polypeptide, ethyl ascorbyl ether, ascorbyl dipalmitate, ascorbyl palmitate, ascorbyl glucoside, ascorbylethylsilanol pectinate, kojic acid, alpha hydroxynan, niacinamide, camellia sinensis oil extract, pheniflorin, phosphatidylinositol, costunolide, soy peptide, salmon extract, helipirone, It may be one or more selected from isosorbide, tocopherol, beta-carotene, phytosterol, and retinol.

[0029] The vitamin may be one or more selected from, for example, vitamin A, vitamin C, and vitamin E.

[0030] At this time, derivatives of vitamin A may include retinoic acid, tretinoic acid, etc. Vitamin A is a general term for organic compounds based on an ionone structure and having an isoprene branch as a side branch, and includes retinol, retinal, retinoic acid, carotenoids, etc.

[0031] Additionally, derivatives of vitamin C may include sodium ascorbylphosphate, magnesium ascorbylphosphate, calcium ascorbylphosphate, ascorbic acid polypeptide, ethyl ascorbyl ether, ascorbyl dipalmitate, ascorbyl palmitate, ascorbyl glucoside, and ascorbylethylsilanol pectinate.

[0032] Additionally, derivatives of vitamin E (tocopherol) may include tocopheryl acetate and α-, β-, γ-, δ-tocopherols and α-, β-, γ-, δ-tocotrienols, tocopheryl linoleate, tocopheryl oleate, tocopheryl nicotinate, tocopheryl succinate, etc.

[0033] The biodegradable polymer may be a single polymer or a block copolymer of different components. The single polymer may be one or more selected from polydioxanone, polylactic acid, polyglycolic acid, and polycaprolactone. In addition, block copolymers include PLGA (poly(lactic acid-co-glycolic acid)), PLCL (poly(lactic acid-co-εcaprolactone)), PDLGA (poly(D-lactic acid-co-glycolic acid)), PLLA-PDLA (poly(L-lactic acid-co-D-lactic acid)), GA-TMC (poly(glycolic acid-co-trimethylene carbonate)), PDO-PGA-TMC (poly(dioxanone-co-glycolic acid-co-trimethylene carbonate)), PLA-PEG (Polylactic acid-co-Polyethylene glycol), PGA-PEG (poly glycolic acid-polyethylene glycol), PCL-PEG (Poly(ε-carprolactone)-poly(ethylene glycol)), PEG-PLGA (polyethylene glycol-polylactic) acid-co-glycolic acid), and PDO-PEG (Polydioxanone-co-polyethylene glycol).

[0034] The molecular weight of the biodegradable polymer may preferably be 10 kDa to 300 kDa, as this range may be desirable for tissue repair.

[0035] The covalent bond may be formed by one or more of, but is not limited to, an esterification reaction or an amide coupling.

[0036] At this time, the active ingredient may have a hydroxyl group capable of esterification with the biodegradable polymer. In addition, the biodegradable polymer may have a carboxyl group capable of esterification with the active ingredient.

[0037] Additionally, the active ingredient may be capable of amide coupling with a biodegradable polymer.

[0038] Specifically, the covalent bond formation step may include a process of dissolving a biodegradable polymer and a coupling agent in a solvent, adding an active ingredient, mixing, washing, and then drying.

[0039] Coupling agents include, for example, N,N'-dicyclohexylcarbodiimide (DCC), 2-(1H_benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU), 2-(1H-7-azabenzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TATU), 1-[(1-(cyano-2-ethoxy-2-oxoethylideneamiooxy)dimethylaminomorpholino methylene)]methanaminium hexafluorophosphate (COMU), N-hydroxybenzotriazole (HOBt), 1-Hydroxy-7-azabenzotriazole (HOAt), It may be at least one selected from sulfo-N-hydroxysuccinimide (Sulfo-NHS) and N-hydroxysuccinimide (NHS).

[0040] Additionally, the process of adding a catalyst to the coupling agent may be further included.

[0041] The catalyst may be, for example, one or more selected from dimethylaminopyridine, 4-(1-pyrrolidinyl)pyridine, 2-halopyridinium salts, N,N'-diisopropylcarbodiimide (DIC), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDAC), and 1-tosylimidazole.

[0042] As a specific example, an esterification reaction may be carried out by the catalyst and at least one selected from among coupling agents, N,N'-dicyclohexylcarbodiimide (DCC), 2-(1H_benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU), 2-(1H-7-azabenzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TATU), and 1-[(1-(cyano-2-ethoxy-2-oxoethylideneamiooxy)dimethylaminomorpholino methylene)]methanaminium hexafluorophosphate.

[0043] The solvent in which the biodegradable polymer and coupling agent are dissolved is not limited, as long as it is a medium in which covalent bonding can occur between the active ingredient and the biodegradable polymer, but may be a polar solvent, a non-polar solvent, a hydrophilic solvent, or a hydrophobic solvent. Furthermore, depending on the physical properties of the active ingredient, the solvent may be an aqueous solvent, an organic solvent, or a co-solvent comprising a mixture of these.

[0044] Step (B) is the step of dispersing the covalent bond formed in Step (A) into a solvent to form fine particles dispersed in the solution. In this step, fine particles can be formed, and their size and shape can be controlled.

[0045] At this time, dispersion can be performed using a vibrating device, an emulsifier, and / or a stirrer.

[0046] Dispersion can be carried out in a solvent, and the solvent may be, but is not limited to, an organic solvent. In this case, the organic solvent may be, for example, one or more selected from tetrahydrofuran, hexafluoroisopropanol, ethanol, methanol, acetone, chloroform, and dichloromethane.

[0047] Additionally, the solution may be a solvent with added emulsifiers and stabilizers.

[0048] The emulsifier is not limited as long as it can exhibit emulsifying action, but may include, for example, a polyethylene oxide-polypropylene oxide-polyethylene oxide terpolymer.

[0049] The stabilizer is not limited to any agent capable of exhibiting a stabilizing effect, but may include, for example, polyvinyl alcohol.

[0050] Such a solution may contain 0.5 to 1.5 wt% of the covalent bond, 1.5 to 2.5 wt% of the emulsifier, 2.5 to 4.0 wt% of the stabilizer, and the remainder of the solvent. When the covalent bond is out of the above range, there is a concern that it is difficult to form a dispersed phase (emulsion). In addition, when the emulsifier and / or stabilizer are out of the above range, there is a concern that it is difficult to control the shape of the fine particles. For example, the covalent bond may become a fiber and difficult to form a spherical shape.

[0051] Step (C) is the step of separating the microparticles formed in step (B) from the solution. In this step, the microparticles can be obtained in a separated state, and their purity can also be controlled.

[0052] In step (C), the separation may include a process of filtering the solution. At this time, the filtration may be performed using an automatic vibration filter, etc. The fine particle separation step may include a process of sequentially performing a first wash, a second wash, and a third wash on the dried material obtained by filtering the solution and freeze-drying the remaining filtrate. At this time, the first wash may use phosphate-buffered saline (PBS), the second wash may use sterilized water, and the third wash may use ethanol. Specifically, the first wash, the second wash, and the third wash may each be performed with 500 to 1,000 parts by weight of PBS, 10,000 to 20,000 parts by weight of sterilized water, and 500 to 1,000 parts by weight of ethanol solution, based on 100 parts by weight of the dried material. Additionally, the fine particle separation step may additionally include a process of drying the third washing material after the third washing is completed.

[0053] Additionally, biodegradable polymer microparticles loaded with an effective ingredient, which is an embodiment of the present invention, can be manufactured using the manufacturing method of the present invention. Such biodegradable polymer microparticles loaded with an effective ingredient may have an average particle size of 1 µm to 200 µm. Beyond this range, there is concern that they may be difficult to use as a biodegradable material for tissue repair.

[0054] In addition, a tissue repair composition, which is an embodiment of the present invention, includes biodegradable polymer microparticles loaded with an effective ingredient, which is an embodiment of the present invention. Such a tissue repair composition may be a plastic prosthesis, a bone filler, or a scaffold for tissue engineering.

[0055] Meanwhile, the tissue repair composition may contain 0.1 to 99.9 wt% of biodegradable polymer microparticles loaded with an active ingredient, which is an embodiment of the present invention. In addition, the composition may further contain a carrier. The carrier may be an aqueous carrier, and the aqueous carrier may be, for example, an injectable aqueous solution such as purified water, physiological saline, or a phosphate buffer solution. In addition, the composition may further contain a solute and / or a lubricant. The solute may be, for example, a cellulose derivative such as carboxymethylcellulose (CMC) or hydroxypropylmethylcellulose (HPMC), hyaluronic acid, lidocaine, polydeoxyribonucleotide (PDRN), or polynucleotide (PN), and the lubricant may be, for example, glycerin.

[0056] Unless otherwise stated, the matters mentioned in the manufacturing method, biodegradable polymer microparticles, and tissue repair composition of the present invention are applied equally to each other within the scope of identity, unless they are contradictory to each other.

[0057] The following examples and experimental examples will be used to examine in more detail the manufacturing method, biodegradable polymer microparticles, and tissue repair composition, which are embodiments of the present invention.

[0058] The reagents and materials used in the examples and experimental examples below are commercially available and of the highest quality, and unless otherwise stated, those purchased from Sigma-Aldrich were used.

[0059] <Example 1> Manufacturing of microparticles loaded with an active ingredient on a single biodegradable polymer

[0060] Mix 90g of PLA with a weight average molecular weight of 10kDa, DCC (2.04g, 1.1eq), and DMAP (0.11g, 0.1eq) and dissolve in 1800g of chloroform, then stir for 1 hour. Add 10g of vitamin C (L-ascorbic acid) and stir for 6 hours. Then, place it in a dialysis tubing (cut off 5KDa) and wash it for 3 days while changing distilled water every 6 hours. Freeze-dry the washed material to obtain a slightly yellow material (covalent compound). This material was confirmed to be a covalent compound through NMR analysis in Experimental Example 1. Meanwhile, dissolve 100g of the material in question in 0.4L of chloroform, add 200g of a polyethylene oxide-polypropylene oxide-polyethylene oxide terpolymer, and stir for more than 12 hours. After that, the polymer solution was added to a 10 L aqueous solution containing 300 g of polyvinyl alcohol and stirred with a stirrer for 12 hours until an emulsified solution was created and maintained. The microparticles in the state of the emulsified solution were placed in an automatic vibration filter, separated, and freeze-dried. 100 g of the dried microparticles were washed with 3,000 g of phosphate buffered saline (PBS). Subsequently, they were washed with 60,000 g of sterilized water maintained at 30 to 40°C. 100 g of the washed microparticles were washed and dried using 500 g of 70 to 80 wt% ethanol to produce biodegradable polymer microparticles (average particle size of about 5 to 20 μm) loaded with an active ingredient.

[0061] <Experimental Example 1> NMR Analysis

[0062] For the covalent compound obtained in Example 1, NMR analysis was performed using CDCl3 or D2O. In addition, NMR analysis was performed for each of PLA and vitamin C using CDCl3 or D2O. NMR analysis was performed using a nuclear magnetic resonance spectrometer (JNM-ECZ500R / S1, JEOL, 500 MHz), and the solvents were as described in FIGS. 2 to 5.

[0063] The results are as shown in Figs. 2 to 5. Fig. 2 is a graph of NMR analysis (covalent bond / CDCl3) performed in Experimental Example 1, Fig. 3 is a graph of NMR analysis (biodegradable polymer / CDCl3) performed in Experimental Example 1, Fig. 4 is a graph of NMR analysis (active ingredient / D2O) performed in Experimental Example 1, and Fig. 5 is a graph of NMR analysis (covalent bond / D2O) performed in Experimental Example 1. From the results {PLA (5.2 ppm, 1.6 ppm), vitamin C (4.1 ppm)}, it can be seen that the covalent bond prepared in Example 1 is a compound formed by covalent bonding of PLA and vitamin C.

[0064] Meanwhile, as shown in FIGS. 3 and 4, peaks can be observed in the solvents (D2O, CDCl3) in which vitamin C and PLA are dissolved, respectively (see FIGS. 3 and 4). However, when vitamin C is covalently bonded to PLA, the peak that appeared in the aqueous solvent (D2O) in its independent state does not appear in the aqueous solvent (D2O) (see FIG. 5). Instead, in the solvent (CDCl3) where the peak of PLA appears, a peak corresponding to vitamin C appears together with a peak corresponding to PLA (see FIG. 2). From these results, it can be seen that vitamin C is recognized as a single substance and dissolved in the solvent (CDCl3) in which PLA is dissolved, rather than in the solvent (D2O) in which it was originally dissolved, as a result of being covalently bonded to PLA. It can also be seen that an active ingredient covalently bonded to a biodegradable polymer in this way exhibits a different behavior from an active ingredient simply mixed with a biodegradable polymer, as in Experimental Example 2. That is, in the case of a mixture by simple mixing (an active ingredient encapsulated in microspheres by mixing), it is difficult to maintain the active ingredient in a mixed state, so the active ingredient cannot help but be released early. However, the present invention can delay the release of the active ingredient.

[0065] <Experimental Example 2> Analysis of the release behavior of effective ingredients

[0066] 5 g of the covalent bond obtained in Example 1 was aliquoted, dissolved in 2 mL of phosphate buffered saline (PBS), and stored in an oven at 36°C. The degradation state of the polymer was confirmed at 15-day intervals using GPC (Waters, 2414 RI detector), and the amount of vitamin C released was confirmed using HPLC (Waters, 2489 UV detector). Specifically, the release amount or release rate of the active ingredient in the covalent bond and the degradation rate of the biodegradable polymer were determined under temperature conditions of 36°C in phosphate buffered saline. The degradation and release behaviors for 210 days are shown in Figures 6 and 7. Figure 6 is a graph showing the polymer degradation characteristics in Experimental Example 2 {graph showing the results of molecular weight measurement over time, x-axis time (days), y-axis molecular weight (PS (polystyrene) standard)}, and Figure 7 is a graph showing the results of vitamin C content measurement over time, x-axis time (days), y-axis VC content (%)}, showing the active ingredient release characteristics in Experimental Example 2.

[0067] As confirmed in Figures 6 and 7, the covalent bond not only delays the release of the active ingredient for a long period of time, but can also effectively release a significant amount of the active ingredient after a certain period of time. That is, the covalent bond shows an active ingredient release amount of less than 50% until 150 days and more than 80% until 210 days. In this way, not only can the release of the active ingredient be delayed for a long period of time, but also unnecessary residue of the active ingredient after a certain period of time can be avoided. Therefore, not only can the active ingredient be continuously released to maintain the effect, but the active ingredient can also exert its effect without unnecessary residue after a certain period of time. In addition, the covalent bond has a section in which the release rate of the active ingredient is faster than the degradation rate of the biodegradable polymer. That is, under a temperature condition of 36 degrees Celsius in phosphate buffered saline, it can be seen that the release rate of the active ingredient is faster than the degradation rate of the biodegradable polymer for a period of at least 100 days and up to 150 days. In this way, since the active ingredient is released faster than the biodegradable polymer decomposition rate, the active ingredient can continue to act while the biodegradable polymer maintains its tissue repair action.

[0068] <Example 2> Manufacturing of microparticles loaded with an active ingredient in a biodegradable polymer, which is a heterogeneous copolymer.

[0069] Mix 90 g of PEG-PLA with a weight average molecular weight of 10 kDa, 100 kDa, 200 kDa, or 300 kDa, DCC (2.04 g, 1.1 eq), and DMAP (0.11 g, 0.1 eq) and dissolve in 1800 g of chloroform, and stir for 1 hour. Add 10 g of vitamin C (L-ascorbic acid) and stir for 6 hours. Then, pour into dialysis tubing (cut off 5 KDa) and wash for 3 days while replacing distilled water at 6-hour intervals. Freeze-dry the washed material to obtain a slightly yellow material (covalent bond). Dissolve 100 g of the material in 0.4 L of chloroform, add 200 g of polyethylene oxide-polypropylene oxide-polyethylene oxide terpolymer, and stir for more than 12 hours. After that, the polymer solution was added to a 10 L aqueous solution containing 300 g of polyvinyl alcohol and stirred with a stirrer for 12 hours until an emulsified solution was created and maintained. The emulsified solution-state microparticles were separated by putting them into an automatic vibrating filter and freeze-dried. 100 g of the dried microparticles were washed with 3,000 g of phosphate-buffered saline (PBS). Subsequently, they were washed with 60,000 g of sterilized water maintained at 30 to 40°C. After washing, 100 g of the microparticles were washed and dried using 500 g of 70 to 80 wt% ethanol to produce biodegradable polymer microparticles loaded with an active ingredient. The average particle size of the produced microparticles was measured using a particle size analyzer (1064 L, CILAS). The results are shown in Table 1.

[0070] <Reference Example 1> Manufacturing of microparticles without active ingredients loaded onto a biodegradable polymer, which is a heterogeneous copolymer.

[0071] 100 g of PEG-PLA having a weight-average molecular weight of 10 kDa, 100 kDa, 200 kDa, or 300 kDa was dissolved in 0.4 L of chloroform, and 200 g of polyethylene oxide-polypropylene oxide-polyethylene oxide terpolymer was added and stirred for more than 12 hours. Then, the polymer solution was added to 10 L of an aqueous solution containing 300 g of polyvinyl alcohol and stirred with a stirrer for 12 hours until an emulsified solution was created and maintained. The fine particles in the emulsified solution were separated by placing them in an automatic vibrating filter and freeze-dried. 100 g of the dried fine particles were washed with 3,000 g of phosphate-buffered saline (PBS). Subsequently, they were washed with 60,000 g of sterilized water maintained at 30 to 40°C. 100 g of washed microparticles were washed and dried with 500 g of 70 to 80 wt% ethanol to produce biodegradable polymer microparticles not loaded with an active ingredient. The average particle size of the produced microparticles was measured using a particle size analyzer (1064 L, CILAS). The results are shown in Table 1.

[0072] Classification Molecular weight (kDa) Average particle size (um) Example 2 1012±10 10048±13 20078±18 300195±13 Reference example 11010±7 10045±15 20075±20 300190±10

[0073] As shown in Table 1, it can be seen that the average particle diameter increases as the molecular weight of the polymer increases. In addition, it can be seen that the average particle diameter also increases with the loading of the active ingredient. In this way, it can be seen that the size and shape of the particles can be controlled by controlling the active ingredient and the molecular weight of the polymer. This effect is also an effect that cannot be achieved in the case of microspheres loaded with the active ingredient. In the case of the present invention, since the active ingredient is linked to the biodegradable polymer by covalent bonds, it is easy to control the loading amount of the active ingredient, and thus the size of the microparticles is also easy to control. However, it is difficult to expect such an effect when the active ingredient is simply loaded into the microspheres. Therefore, according to the present invention, the size of the microparticles, the loading amount of the active ingredient, and the release pattern of the active ingredient can be controlled as intended. In addition, as discussed above, it can be seen that the present invention can effectively produce microparticles in which the active ingredient is loaded by covalent bonds not only to a single biodegradable polymer but also to a heterogeneous biodegradable polymer. In addition, the present invention can be seen that the active ingredient can continuously exert its effect while the biodegradable polymer maintains its tissue repair function, and does not remain unnecessarily after a certain period of time, so that it can exert its effect in the manner originally planned.

[0074] According to the present invention, biodegradable polymer microparticles can be effectively manufactured to enable delayed release of active ingredients. Therefore, the present invention has industrial applicability.

Claims

1. A method for manufacturing biodegradable polymer microparticles loaded with effective ingredients, (A) A covalent bond formation step of forming a covalent bond by covalently linking the above effective ingredient with the biodegradable polymer; (B) a fine particle dispersion step of dispersing the covalent bond in a solvent to form fine particles dispersed in the solution; and (C) including a microparticle separation step for separating the microparticles from the solution, The above biodegradable polymer is polylactic acid, The solution comprises 0.5 to 1.5 wt% of the covalent bond, 1.5 to 2.5 wt% of an emulsifier, and 2.5 to 4.0 wt% of a stabilizer. The above covalent bond is a method for manufacturing biodegradable polymer microparticles loaded with an effective ingredient having an effective ingredient release amount of 50% or less for 150 days and 80% or more for 210 days.

2. Biodegradable polymer microparticles loaded with an effective ingredient manufactured by the manufacturing method of paragraph 1.

3. A tissue repair composition comprising the biodegradable polymer microparticles of paragraph 2.

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