Implant comprising biodegradable polymer, manufacturing method therefor, and composition therefor

Abstract

Provided is an implant comprising a first biodegradable polymer and a second biodegradable polymer, wherein the first biodegradable polymer comprises copolymerized polyhydroxyalkanoate (PHA), and the copolymerized PHA comprises, on the basis of the total weight of the copolymerized PHA, 0.1-50 wt% of a repeating unit derived from 4-hydroxybutyrate (4-HB).

Description

Implant containing biodegradable polymer, method for producing same, and composition therefor

[0001] The present invention relates to an implant comprising a biodegradable polymer and a method for manufacturing the same. More specifically, the present invention relates to an orthopedic implant comprising a biodegradable polymer and having enhanced osteodifferentiation and osseointegration capabilities, and a method for manufacturing the same.

[0002]

[0003] Biodegradable polymers are attracting attention in various fields, including medicine, agriculture, and the environment, due to their unique decomposition properties. In the medical field, they offer the advantage of eliminating the need for surgical removal after healing, as they aid in the healing process and are metabolized by the body after fulfilling their function, unlike non-degradable polymers like metals and ceramics.

[0004] These biodegradable polymers are broadly divided into natural and synthetic biodegradable polymers. Natural biodegradable polymers, made from natural materials, exhibit excellent biological compatibility and bioadaptability, resulting in relatively low immune responses in the body. However, compared to synthetic biodegradable polymers, they exhibit weaker physical strength and durability, requiring the use of appropriate materials for each application.

[0005] Currently, polyglycolide (PGA), polylactide (PLLA), and polycaprolactone (PCL) are the main materials used in absorbable implants, and most utilize synthetic biodegradable polymers. PLLA, the most commonly used, boasts high strength but is vulnerable to impact, so materials copolymerized with other materials such as PGA or PCL (PLGA or PLCL) are sometimes used. For example, Korean Patent Publication No. 2022-0047788 discloses an implant made of a biodegradable composite material comprising PLLA, PGA, PCL, or a copolymer thereof.

[0006] Polyhydroxyalkanoate (PHA) is a biodegradable polymer derived from microorganisms. It breaks down in the human body and is non-toxic, making it a safe material. These advantages make it suitable for a variety of medical applications, including fracture repair, cardiovascular materials, artificial joints, and surgical instruments. PHA comes in various types, including PHB, P3HB, P4HB, PHV, and PHH, and each type has different properties. Depending on the application, the appropriate material can be selected, or a copolymer, such as P(3HB-4HB), can be created and applied.

[0007] The development of absorbable implants for fracture treatment containing these bio-derived polymers is expected to significantly improve the quality of fracture treatment, potentially shortening patient recovery times and reducing the burden of rehabilitation. Furthermore, it is expected to contribute to reducing medical costs associated with fracture treatment, which is becoming increasingly important in an aging society.

[0008] [Prior Art Literature]

[0009] (Patent Document 1) Korean Patent Publication No. 2022-0047788

[0010]

[0011] The object of the present invention is to provide an implant comprising a biodegradable polymer and having strength and stability suitable for orthopedics and excellent osteodifferentiation and bone union capabilities, a method for manufacturing the same, and a composition therefor.

[0012]

[0013] The present invention provides an implant comprising a first biodegradable polymer and a second biodegradable polymer, wherein the first biodegradable polymer comprises a copolymerized polyhydroxyalkanoate (PHA), and the copolymerized polyhydroxyalkanoate (PHA) comprises a repeating unit derived from 4-hydroxybutyrate (4-HB) in an amount of 0.1 wt% to 50 wt% based on the total weight of the copolymerized polyhydroxyalkanoate (PHA).

[0014] In one embodiment, the implant may comprise a blend of the first biodegradable polymer and the second biodegradable polymer.

[0015] In another embodiment, the implant may include a central portion and a covering portion, wherein the covering portion may include the first biodegradable polymer, and the central portion may include the second biodegradable polymer.

[0016] In another embodiment, the implant includes a central portion and a covering portion, wherein the central portion and the covering portion each include a blend of the first biodegradable polymer and the second biodegradable polymer, and the content of the first biodegradable polymer included in the covering portion based on the total weight of the blend included in the covering portion may be greater than the content of the first biodegradable polymer included in the central portion based on the total weight of the blend included in the central portion.

[0017] In another embodiment, the implant comprises at least one intermediate portion disposed between the central portion and the covering portion, the at least one intermediate portion comprising a blend of the first biodegradable polymer and the second biodegradable polymer, and the content of the first biodegradable polymer included in the covering portion based on the total weight of the blend included in the covering portion may be greater than the content of the first biodegradable polymer included in the intermediate portion based on the total weight of the blend included in the intermediate portion, and the content of the first biodegradable polymer included in the intermediate portion based on the total weight of the blend included in the intermediate portion may be greater than the content of the first biodegradable polymer included in the central portion based on the total weight of the blend included in the central portion.

[0018] In another embodiment, the implant may have a porous structure including pores with a size of 10 nm to 10 μm.

[0019] In another embodiment, the copolymerized polyhydroxyalkanoate (PHA) is composed of 2-hydroxybutyrate (2-HB), 3-hydroxybutyrate (3-HB), 3-hydroxypropionate (3-HP), 3-hydroxyvalerate (3-HV), 3-hydroxyhexanoate (3-HH), 3-hydroxyheptanoate (3-Hhep), 3-hydroxyoctanoate (3-HO), 3-hydroxynonanoate (3-HN), 3-hydroxydecanoate (3-HD), 3-hydroxydodecanoate (3-HDd), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV), and 6-hydroxyhexanoate (6-HH). It may further include repeating units derived from one or more monomers selected from the group.

[0020] In another embodiment, the first biodegradable polymer may further comprise one or more polymers selected from the group consisting of poly(3-hydroxybutyrate) (P3HB), poly(4-hydroxybutyrate) (P4HB), poly(3-hydroxyhexanoate) (P3HH), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB-3HH), poly(3-hydroxyoctanoate) (P3HO), and poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) (P3HB-3HO).

[0021] In another embodiment, the second biodegradable polymer is a mixture of one or more selected from synthetic biodegradable polymers and natural biodegradable polymers excluding polyhydroxyalkanoate (PHA), wherein the synthetic biodegradable polymers include polylactic acid (PLA), polycaprolactone (PCL), polyglycolic acid (PGA), poly(lactic acid-co-caprolactone) (PLCL), poly(lactic acid-co-glycolic acid) (PLGA), polybutylene succinate (PBS), and poly(butylene adipate-co-terephthalate) (PBAT); and the natural biodegradable polymers may include starch, silk fibroin, chitosan, chitin, cellulose, collagen, and gelatin.

[0022] In another embodiment, the copolymerized polyhydroxyalkanoate (PHA) may be included in an amount of 10 wt% to 50 wt%, based on the total weight of the first biodegradable polymer and the second biodegradable polymer.

[0023] In another embodiment, the implant may further comprise one or more additives selected from bioactive glass fibers or ceramics.

[0024] In another embodiment, the implant further comprises one or more drugs for enhancing bone regeneration, and the drugs may be included by being coated on the surface of the implant, or by being blended with the first biodegradable polymer and the second biodegradable polymer, or may be included in a concentration gradient from the surface to the interior of the implant.

[0025] In another embodiment, the implant may be manufactured as a specimen having a diameter of 1.5 mm and a length of 50 mm, and may have a measured tensile strength of 40 MPa to 70 MPa and an elongation of 3.2% to 10%.

[0026] In another embodiment, the implant may have a roughness on the surface of 1 μm to 10 μm in depth, or may have a grid pattern, wave pattern, or stripe pattern with spacing of 1 μm to 10 μm.

[0027] In another embodiment, the implant may exhibit a cell viability of 70% or more based on a cell viability of 100% for the control group of the dissolution solvent in a cytotoxicity test using the dissolution solvent.

[0028] In another embodiment, the implant may be transplanted into a fractured femur tissue of a rat, and the stiffness of the femur tissue harvested two months later may be 120 N / mm or more.

[0029] In addition, the present invention provides a method for manufacturing an implant, comprising the steps of preparing a biodegradable polymer including a first biodegradable polymer and a second biodegradable polymer; and the step of forming an implant using the biodegradable polymer, wherein the first biodegradable polymer includes a copolymerized polyhydroxyalkanoate (PHA), and the copolymerized polyhydroxyalkanoate (PHA) includes a repeating unit derived from 4-hydroxybutyrate (4-HB) in an amount of 0.1 wt% to 50 wt% based on the total weight of the copolymerized polyhydroxyalkanoate (PHA).

[0030] In one embodiment, the molding may be injection molding or 3D printing molding.

[0031] In another embodiment, the injection molding may be performed under conditions of an extrusion temperature of 100°C to 210°C, an injection temperature of 150°C to 200°C, and an annealing temperature of 80°C to 110°C.

[0032] In another embodiment, the 3D printing molding may be performed under the conditions of a printing temperature of 150°C to 200°C, an injection speed of 200 mm / min to 400 mm / min, a pressure of 200 kPa to 400 kPa, and a printing duration of 60 minutes or less.

[0033] In another embodiment, after the forming, at least one surface treatment step may be additionally included among a step of imparting roughness or a pattern to the surface through blasting, molding, or laser treatment, and a step of imparting hydrophilicity to the surface through plasma treatment.

[0034] In addition, the present invention provides an implant composition comprising a first biodegradable polymer and a second biodegradable polymer, wherein the first biodegradable polymer comprises a copolymerized polyhydroxyalkanoate (PHA), and the copolymerized polyhydroxyalkanoate (PHA) comprises a repeating unit derived from 4-hydroxybutyrate (4-HB) in an amount of 0.1 wt% to 50 wt% based on the total weight of the copolymerized polyhydroxyalkanoate (PHA).

[0035]

[0036] The implant according to the present invention comprises a first biodegradable polymer and a second biodegradable polymer including a copolymerized polyhydroxyalkanoate (PHA), and exhibits strength and stability suitable as a material for fixing hard tissues such as orthopedic implants, such as pins, screws, and fixation plates, and has excellent bone formation performance and osseointegration performance.

[0037]

[0038] Figure 1a illustrates an implant (11) according to one embodiment.

[0039] Fig. 1b shows an implant (12) according to another embodiment (100: center, 300: covering).

[0040] Fig. 1c shows an implant (13) according to another embodiment (100: central part, 200: middle part, 300: covering part).

[0041] Figure 2 schematically shows the surface roughness of an implant.

[0042] Figure 3 shows the results of a tensile test of the implant.

[0043] Figure 4 shows the results of a cytotoxicity test of the implant.

[0044] Figure 5 shows the results of WST-1 analysis of the implant.

[0045] Figure 6 shows the results of the bone differentiation induction test of the implant.

[0046] Figure 7 shows an outline of the rat femur fracture test.

[0047] Figure 8 shows the histopathological analysis results of a rat femur fracture test.

[0048] Figure 9 shows micro-CT 2D and 3D images of a rat femur fracture test.

[0049] Figures 10a and 10b show the results of radiological analysis of a 2-month rat femur sample.

[0050] Figures 11a and 11b show the results of radiological analysis of a 4-month rat femur sample.

[0051] Figures 12a and 12b show the biomechanical analysis results of a rat femur fracture test.

[0052]

[0053] The invention is described in detail below through examples. The examples are not limited to the content disclosed below and may be modified in various ways as long as the spirit of the invention remains intact.

[0054] The word "comprising" or "including" in this specification is intended to specify particular features, regions, steps, processes, elements and / or components, and does not exclude the presence or addition of other features, regions, steps, processes, elements and / or components, unless specifically stated to the contrary.

[0055] In this specification, the terms "first," "second," etc. are used to describe various components, and the components should not be limited by the terms. The terms are used for the purpose of distinguishing one component from another.

[0056] In the numerical ranges that limit the size, physical properties, etc. of the components described in this specification, if a numerical range limited only to the upper limit and a numerical range limited only to the lower limit are separately exemplified, it should be understood that a numerical range in which these upper and lower limits are combined is also included in the exemplary range.

[0057]

[0058] biodegradable polymers

[0059] The implant according to the present invention comprises a biodegradable polymer, and may comprise, for example, a bio-derived polymer.

[0060] Specifically, the implant may include two or more types of biodegradable polymers.

[0061] In one embodiment, the implant comprises a first biodegradable polymer and a second biodegradable polymer.

[0062] In another embodiment, the implant may comprise a blend of the first biodegradable polymer and the second biodegradable polymer.

[0063] The first biodegradable polymer and the second biodegradable polymer may be different polymers.

[0064] The first biodegradable polymer and the second biodegradable polymer may each include one or two or more types of biodegradable polymers.

[0065] In one embodiment, the first biodegradable polymer is polyhydroxyalkanoate (PHA).

[0066] The above polyhydroxyalkanoate (PHA) can have similar properties to synthetic polymers such as polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polybutylene succinate terephthalate (PBST), and polybutylene succinate adipate (PBSA) derived from conventional petroleum, and exhibits excellent biodegradability and also excellent biocompatibility.

[0067] Specifically, the PHA is a natural polyester-based biodegradable polymer that accumulates within microbial cells and can ultimately be decomposed into carbon dioxide, water, and organic matter. In particular, since the PHA can be decomposed in vivo, an implant manufactured using a biodegradable polymer composition containing the PHA can be utilized in the medical field as an absorbable medical device.

[0068] The above PHA can be formed by enzyme-catalyzed polymerization of one or more monomer repeating units within a living cell.

[0069] In one specific example, the first biodegradable polymer comprises a copolymerized polyhydroxyalkanoate (PHA).

[0070] For example, the first biodegradable polymer may include one or more copolymerized polyhydroxyalkanoates (PHAs).

[0071] The above copolymerized polyhydroxyalkanoate (PHA) may include a copolymer containing two or more different repeating units in which the different repeating units are randomly distributed in the polymer chain.

[0072] In one embodiment, the copolymerized polyhydroxyalkanoate (PHA) comprises repeating units derived from 4-hydroxybutyrate (4-HB).

[0073] In the present invention, it is important to control the content of the 4-HB repeating unit in the copolymer PHA. That is, in order to realize the physical properties desired in the present invention, particularly to enhance biodegradability and realize excellent mechanical properties, the content of the 4-HB repeating unit in the copolymer PHA may be important.

[0074] The content of the repeating unit derived from the 4-hydroxybutyrate (4-HB) based on the total weight of the copolymerized polyhydroxyalkanoate (PHA) may be 0.1 wt% or more, 5 wt% or more, 10 wt% or more, 12 wt% or more, 13 wt% or more, 15 wt% or more, 17 wt% or more, 18 wt% or more, 20 wt% or more, or 25 wt% or more, and may be 50 wt% or less, 45 wt% or less, 43 wt% or less, 42 wt% or less, 40 wt% or less, or 35 wt% or less.

[0075] For example, the content of the repeating unit derived from the 4-hydroxybutyrate (4-HB) based on the total weight of the copolymerized polyhydroxyalkanoate (PHA) is 0.1 wt% to 50 wt%, 1 wt% to 50 wt%, 2 wt% to 50 wt%, 3 wt% to 50 wt%, 5 wt% to 50 wt%, 10 wt% to 50 wt%, 1 wt% to 40 wt%, 1 wt% to 30 wt%, 1 wt% to 29 wt%, 1 wt% to 25 wt%, 1 wt% to 24 wt%, 2 wt% to 20 wt%, 2 wt% to 23 wt%, 3 wt% to 20 wt%, 3 wt% to 15 wt%, 4 wt% to 18 wt%, 5 wt% to 15 wt%, 8 wt% to It may be, but is not limited to, 12 wt%, 9 wt% to 12 wt%, 15 wt% to 50 wt%, 20 wt% to 50 wt%, or 25 wt% to 50 wt%.

[0076] In one specific example, the copolymerized polyhydroxyalkanoate (PHA) contains repeating units derived from 4-hydroxybutyrate (4-HB) in an amount of 0.1 wt% to 50 wt% based on the total weight of the copolymerized polyhydroxyalkanoate (PHA).

[0077] More specifically, the copolymerized polyhydroxyalkanoate (PHA) contains repeating units derived from 4-hydroxybutyrate (4-HB) in an amount of 3 wt% to 20 wt% based on the total weight of the copolymerized polyhydroxyalkanoate (PHA).

[0078] In this way, the copolymer PHA includes at least one 4-HB repeating unit, and the crystallinity of the copolymer PHA can be controlled by controlling the content of the 4-HB repeating unit. In other words, the copolymer PHA can be a polymer with controlled crystallinity.

[0079] The above-mentioned copolymer PHA with controlled crystallinity may have controlled crystallinity and amorphousness by increasing irregularity in the molecular structure, and specifically, may be one in which the type of monomer, the ratio of monomers, or the type and / or content of isomers is controlled.

[0080] In addition, the copolymerized polyhydroxyalkanoate (PHA) is selected from the group consisting of 2-hydroxybutyrate (2-HB), 3-hydroxybutyrate (3-HB), 3-hydroxypropionate (3-HP), 3-hydroxyvalerate (3-HV), 3-hydroxyhexanoate (3-HH), 3-hydroxyheptanoate (3-Hhep), 3-hydroxyoctanoate (3-HO), 3-hydroxynonanoate (3-HN), 3-hydroxydecanoate (3-HD), 3-hydroxydodecanoate (3-HDd), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV), and 6-hydroxyhexanoate (6-HH). It may further include repeating units derived from one or more monomers.

[0081] Specifically, the copolymerized polyhydroxyalkanoate (PHA) may further include one or more repeating units selected from the group consisting of 3-hydroxybutyrate (3-HB), 3-hydroxypropionate (3-HP), 3-hydroxyvalerate (3-HV), 3-hydroxyhexanoate (3-HH), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV), and 6-hydroxyhexanoate (6-HH).

[0082] More specifically, the copolymer PHA may include a copolymer comprising repeating units derived from 3-HB and repeating units derived from 4-HB. For example, the copolymer PHA may include poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (3HB-co-4HB).

[0083] For example, the content of the repeating unit derived from the 3-HB based on the total weight of the copolymer PHA may be 50 wt% or more, 55 wt% or more, 60 wt% or more, 64 wt% or more, 70 wt% or more, or 75 wt% or more, and may also be 99.9 wt% or less, 99 wt% or less, 95 wt% or less, 90 wt% or less, 85 wt% or less, 80 wt% or less, or 75 wt% or less.

[0084] Additionally, the copolymer PHA may include isomers. For example, the copolymer PHA may include structural isomers, enantiomers, or geometric isomers. Specifically, the PHA may include structural isomers.

[0085] The above copolymer PHA may have a glass transition temperature (Tg) of, for example, -45°C to 80°C, -35°C to 80°C, -30°C to 80°C, -25°C to 75°C, -20°C to 70°C, -35°C to 5°C, -25°C to 5°C, -35°C to 0°C, -25°C to 0°C, -30°C to -10°C, -35°C to -15°C, -35°C to -20°C, -20°C to 0°C, -15°C to 0°C, or -15°C to -5°C.

[0086] The above copolymer PHA may have a crystallization temperature (Tc) that may not be measured, for example, or may be, for example, from 70°C to 120°C, from 75°C to 120°C, from 75°C to 115°C, from 75°C to 110°C, or from 90°C to 110°C.

[0087] The above copolymer PHA may have a melting temperature (Tm) that may not be measured, for example, or may be from 100°C to 170°C, from 110°C to 150°C, or from 120°C to 140°C.

[0088] The above copolymer PHA may have a weight average molecular weight (Mw) of, for example, 10,000 g / mol to 1,200,000 g / mol. For example, the weight average molecular weight of the copolymer PHA is 50,000 g / mol to 1,200,000 g / mol, 100,000 g / mol to 1,200,000 g / mol, 50,000 g / mol to 1,000,000 g / mol, 100,000 g / mol to 1,000,000 g / mol, 100,000 g / mol to 900,000 g / mol, 200,000 g / mol to 1,200,000 g / mol, 250,000 g / mol to 1,150,000 g / mol, 300,000 g / mol to 1,100,000 g / mol, 350,000 g / mol to 1,000,000 g / mol, 350,000 g / mol to 950,000 g / mol, 100,000 g / mol to 900,000 g / mol, 200,000 g / mol to 800,000 g / mol, 200,000 g / mol to 700,000 g / mol, 250,000 g / mol to 650,000 g / mol, 200,000 g / mol to 400,000 g / mol, 300,000 g / mol to 800,000 g / mol, 300,000 g / mol to 600,000 g / mol, 400,000 g / mol to 800,000 g / mol, 500,000 g / mol to 1,200,000 g / mol, It may be 500,000 g / mol to 1,000,000 g / mol, 550,000 g / mol to 1,050,000 g / mol, 550,000 g / mol to 900,000 g / mol, or 600,000 g / mol to 900,000 g / mol.

[0089] In one specific example, the copolymer PHA may be a crystalline or semi-crystalline PHA. For example, the crystalline or semi-crystalline PHA may contain, for example, 1 wt% to 25 wt% of the 4-HB repeating unit based on the total weight of the copolymer PHA. In addition, the glass transition temperature (Tg) of the crystalline or semi-crystalline PHA may be, for example, -20°C to 0°C, the crystallization temperature (Tc) may be, for example, 75°C to 115°C, and the melting temperature (Tm) may be, for example, 110°C to 160°C.

[0090] In another embodiment, the first biodegradable polymer may further comprise one or more polymers selected from the group consisting of poly(3-hydroxybutyrate) (P3HB), poly(4-hydroxybutyrate) (P4HB), poly(3-hydroxyhexanoate) (P3HH), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB-3HH), poly(3-hydroxyoctanoate) (P3HO), and poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) (P3HB-3HO).

[0091] In another embodiment, the first biodegradable polymer may further comprise one or more short-chain or medium-chain copolymerized polyhydroxyalkanoates (PHAs).

[0092] The second biodegradable polymer may be a mixture of one or more selected from among synthetic biodegradable polymers and natural biodegradable polymers excluding polyhydroxyalkanoate (PHA).

[0093] Examples of the above synthetic biodegradable polymers may include polylactic acid (PLA), polycaprolactone (PCL), polyglycolic acid (PGA), poly(lactic acid-co-caprolactone) (PLCL), poly(lactic acid-co-glycolic acid) (PLGA), polybutylenesuccinate (PBS), and poly(butyleneadipate-co-terephthalate) (PBAT).

[0094] Additionally, examples of the above natural biodegradable polymers may include starch, silk fibroin, chitosan, chitin, cellulose, collagen, and gelatin.

[0095] In one specific example, the second biodegradable polymer may be polylactide (PLA).

[0096] For example, the second biodegradable polymer may include one or more types of polylactide (PLA).

[0097] Specifically, the second biodegradable polymer may include poly-L-lactide (PLLA), poly-D-lactide (PDLA), poly-DL-lactide (PDLLA), or blends thereof.

[0098] Polylactide (PLA) has high strength but low flexibility, making it prone to fracture. However, by blending it with copolymerized polyhydroxyalkanoate (PHA), flexibility is provided, which can improve implant stability, bone formation performance, and osseointegration performance.

[0099]

[0100] Additives and drugs

[0101] The above implant may further include one or more additives and / or drugs in addition to the biodegradable polymer.

[0102] In one embodiment, the implant may further comprise one or more additives selected from, but not limited to, bioactive glass fibers or ceramics.

[0103] For example, the bioactive ceramics may include hydroxyapatite (HAP), wollastonite, tricalcium phosphate (TCP), dicalcium phosphate dihydrate (DCPD), tetracalcium phosphate (TTCP), octacalcium phosphate (OCP), amorphous calcium phosphate (ACP), etc.

[0104] In another embodiment, the implant may further comprise one or more drugs for enhancing bone regeneration.

[0105] For example, the drugs may include tricalcium phosphate (TCP), beta-tricalcium phosphate (β-TCP), hydroxyapatite-tricalcium phosphate (HTCP), deoxyribonucleotide triphosphates (dNTPs), bone morphogenetic proteins (BMPs), calcium (Ca), magnesium (Mg), etc.

[0106] In one specific example, the drug may be included by being coated on the surface of the implant.

[0107] In another embodiment, the drug may be included blended with the first biodegradable polymer and the second biodegradable polymer.

[0108] In another specific embodiment, the drug may be included in a concentration gradient from the surface to the interior of the implant, for example, the drug may be included such that the concentration of the drug gradually decreases from the surface to the interior, in which case the drug release amount may be initially rapid and then gradually decrease.

[0109]

[0110] Composition of the implant

[0111] Figure 1a illustrates an implant according to one embodiment.

[0112] Referring to Fig. 1a, the implant (11) may have a single-layer configuration.

[0113] In one embodiment, the implant may comprise a blend of the first biodegradable polymer and the second biodegradable polymer.

[0114] The content of the first biodegradable polymer may be 0.1 wt% or more, 0.5 wt% or more, 1 wt% or more, 3 wt% or more, 5 wt% or more, 10 wt% or more, 15 wt% or more, 20 wt% or more, or 25 wt% or more, and may also be 50 wt% or less, 45 wt% or less, 40 wt% or less, 35 wt% or less, 30 wt% or less, or 25 wt% or less, based on the total weight of the first biodegradable polymer and the second biodegradable polymer (i.e., the total weight of the blend).

[0115] Specifically, the content of the first biodegradable polymer may be 0.1 wt% to 50 wt%, 1 wt% to 50 wt%, 5 wt% to 50 wt%, 10 wt% to 50 wt%, 15 wt% to 50 wt%, 20 wt% to 50 wt%, 25 wt% to 50 wt%, 0.1 wt% to 40 wt%, 5 wt% to 40 wt%, 15 wt% to 40 wt%, 25 wt% to 40 wt%, 5 wt% to 35 wt%, 15 wt% to 35 wt%, or 25 wt% to 35 wt%, based on the total weight of the first biodegradable polymer and the second biodegradable polymer.

[0116] In addition, the content of the second biodegradable polymer may be 50 wt% or more, 55 wt% or more, 60 wt% or more, 64 wt% or more, 70 wt% or more, or 75 wt% or more, based on the total weight of the first biodegradable polymer and the second biodegradable polymer, and may also be 99.9 wt% or less, 99 wt% or less, 95 wt% or less, 90 wt% or less, 85 wt% or less, 80 wt% or less, or 75 wt% or less, and specifically may be 50 wt% to 90 wt%.

[0117] For example, the weight ratio of the first biodegradable polymer and the second biodegradable polymer may be 0.1:99.9 to 50:50, 1:99 to 50:50, 5:95 to 50:50, 5:95 to 40:60, 10:90 to 50:50, 15:85 to 40:60, 20:80 to 40:60, or 25:75 to 40:60.

[0118] In one embodiment, the implant may comprise a blend of a first biodegradable polymer comprising the copolymerized polyhydroxyalkanoate (PHA) and a second biodegradable polymer.

[0119] The content of the copolymerized polyhydroxyalkanoate (PHA) may be 0.1 wt% or more, 0.5 wt% or more, 1 wt% or more, 3 wt% or more, 5 wt% or more, 10 wt% or more, 15 wt% or more, 20 wt% or more, or 25 wt% or more, and may also be 50 wt% or less, 45 wt% or less, 40 wt% or less, 35 wt% or less, 30 wt% or less, or 25 wt% or less, based on the total weight of the first biodegradable polymer and the second biodegradable polymer.

[0120] Specifically, the content of the copolymerized polyhydroxyalkanoate (PHA) may be 0.1 wt% to 50 wt%, 1 wt% to 50 wt%, 5 wt% to 50 wt%, 10 wt% to 50 wt%, 15 wt% to 50 wt%, 20 wt% to 50 wt%, 25 wt% to 50 wt%, 0.1 wt% to 40 wt%, 5 wt% to 40 wt%, 15 wt% to 40 wt%, 25 wt% to 40 wt%, 5 wt% to 35 wt%, 15 wt% to 35 wt%, or 25 wt% to 35 wt%, based on the total weight of the first biodegradable polymer and the second biodegradable polymer.

[0121] For example, the copolymerized polyhydroxyalkanoate (PHA) may be included in an amount of 10 wt% to 50 wt% based on the total weight of the first biodegradable polymer and the second biodegradable polymer.

[0122] In one specific example, the first biodegradable polymer may be polyhydroxyalkanoate (PHA) and the second biodegradable polymer may be polylactide (PLA).

[0123] For example, the weight ratio of the polyhydroxyalkanoate (PHA) and the polylactide (PLA) may be 0.1:99.9 to 50:50, 1:99 to 50:50, 5:95 to 50:50, 5:95 to 40:60, 10:90 to 50:50, 15:85 to 40:60, 20:80 to 40:60, or 25:75 to 40:60.

[0124] Figure 1b illustrates an implant according to another embodiment.

[0125] Referring to FIG. 1b, the implant (12) according to the other embodiment includes a central portion (100) and a covering portion (300).

[0126] In one specific example, the covering portion may include the first biodegradable polymer, and the central portion may include the second biodegradable polymer.

[0127] In another specific example, the central portion and the covering portion each include a blend of the first biodegradable polymer and the second biodegradable polymer, and the content of the first biodegradable polymer included in the covering portion based on the total weight of the blend included in the covering portion may be greater than the content of the first biodegradable polymer included in the central portion based on the total weight of the blend included in the central portion.

[0128] In another specific example, the central portion and the covering portion each include the first biodegradable polymer, the second biodegradable polymer, or a blend thereof, and the weight ratio of the first biodegradable polymer to the second biodegradable polymer included in the covering portion may be greater than the weight ratio of the first biodegradable polymer to the second biodegradable polymer included in the central portion.

[0129] The size and thickness of the central portion and the covering portion may vary depending on the content ratio of the first biodegradable polymer and the second biodegradable polymer included in the implant.

[0130] Figure 1c illustrates an implant according to another embodiment.

[0131] Referring to FIG. 1c, an implant (13) according to another embodiment includes a central portion (100), a covering portion (300), and one or more intermediate portions (200) disposed therebetween.

[0132] For example, the covering portion may have the highest content of the first biodegradable polymer, the central portion may have the highest content of the second biodegradable polymer, and the one or more intermediate portions may have a higher content of the first biodegradable polymer the closer they are to the covering portion, and a higher content of the second biodegradable polymer the closer they are to the central portion.

[0133] In one specific example, the covering portion may include the first biodegradable polymer, and the central portion may include the second biodegradable polymer.

[0134] In another specific example, the central portion and the covering portion each include a blend of the first biodegradable polymer and the second biodegradable polymer, and the content of the first biodegradable polymer included in the covering portion based on the total weight of the blend included in the covering portion may be greater than the content of the first biodegradable polymer included in the central portion based on the total weight of the blend included in the central portion.

[0135] The implant comprises at least one intermediate portion disposed between the central portion and the covering portion, wherein the at least one intermediate portion comprises a blend of the first biodegradable polymer and the second biodegradable polymer, and the content of the first biodegradable polymer included in the covering portion based on the total weight of the blend included in the covering portion may be greater than the content of the first biodegradable polymer included in the intermediate portion based on the total weight of the blend included in the intermediate portion, and the content of the first biodegradable polymer included in the intermediate portion based on the total weight of the blend included in the intermediate portion may be greater than the content of the first biodegradable polymer included in the central portion based on the total weight of the blend included in the central portion.

[0136] In another specific embodiment, the central portion, the intermediate portion, and the covering portion may each include the first biodegradable polymer, the second biodegradable polymer, or a blend thereof. The weight ratio of the first biodegradable polymer to the second biodegradable polymer included in each of the central portion, the intermediate portion, and the covering portion may be highest in the covering portion and lowest in the central portion. Additionally, the weight ratio of the second biodegradable polymer to the first biodegradable polymer included in each of the central portion, the intermediate portion, and the covering portion may be highest in the central portion and lowest in the covering portion.

[0137] In another specific embodiment, the implant comprises two or more intermediate portions disposed between the central portion and the covering portion, wherein the two or more intermediate portions each comprise a blend of the first biodegradable polymer and the second biodegradable polymer, and the content of the first biodegradable polymer contained in each intermediate portion based on the total weight of the blend contained in each intermediate portion may be higher the closer the intermediate portion is to the covering portion. In addition, the content of the second biodegradable polymer contained in each intermediate portion based on the total weight of the blend contained in each intermediate portion may be higher the closer the intermediate portion is to the central portion.

[0138] For example, the covering portion may be formed of the first biodegradable polymer (e.g., PHA), and the mixing ratio of the second biodegradable polymer (e.g., PLA) may gradually increase toward the center. The difference in the content of the first biodegradable polymer or the second biodegradable polymer that increases or decreases in each intermediate portion may be, for example, 5 wt% to 50 wt%.

[0139] The size and thickness of the central portion, the middle portion, and the covering portion may vary depending on the content ratio of the first biodegradable polymer and the second biodegradable polymer included in the implant.

[0140] The shape of the above implant is not particularly limited, and may be, for example, cylindrical (or pin-shaped), square column-shaped, or plate-shaped.

[0141] The above implant may have a porous structure.

[0142] For example, the implant may include multiple pores.

[0143] Specifically, the implant may have a porous structure including pores with a size of 10 nm to 10 μm.

[0144] Additionally, the implant may have a rough surface or a pattern.

[0145] In one embodiment, the implant may have a uniform roughness on its surface.

[0146] In one specific example, the implant may have a roughness on the surface of 1 μm to 10 μm in depth. More specifically, the implant may have micro-concave portions on the surface of 1 μm to 10 μm in depth and 1 μm to 10 μm in spacing.

[0147] In another specific embodiment, the implant may additionally have a small roughness within a large roughness on its surface. More specifically, the implant may have a first micro-concave portion having a depth of 1 μm to 10 μm and a spacing of 1 μm to 10 μm on its surface, and may have a second micro-concave portion having a depth of 0.1 μm to 1 μm and a spacing of 0.1 μm to 1 μm on the surface of the first micro-concave portion (see FIG. 2).

[0148] In another embodiment, the implant may have a pattern on its surface.

[0149] Specifically, the implant may have a grid pattern, wave pattern, or stripe pattern with a spacing of 1 μm to 10 μm on the surface.

[0150] The implant according to the present invention comprises a first biodegradable polymer and a second biodegradable polymer including a copolymerized polyhydroxyalkanoate (PHA), and exhibits strength and stability suitable as a material for fixing hard tissues such as orthopedic implants, such as pins, screws, and fixation plates, and has excellent bone formation performance and osseointegration performance.

[0151] For example, the tensile strength of the implant may be 35 MPa or more, 40 MPa or more, 45 MPa or more, or 50 MPa or more, and may also be 75 MPa or less, 70 MPa or less, 65 MPa or less, or 60 MPa or less. As a specific example, the tensile strength of the implant may be from 40 MPa to 70 MPa. More specifically, the tensile strength of the implant may be from 40 MPa to 60 MPa, or from 50 MPa to 60 MPa.

[0152] The elongation of the implant may be 2% or more, 3% or more, 3.2% or more, or 4% or more, and may also be 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, or 5% or less. As a specific example, the elongation of the implant may be 3.2% to 10%. More specifically, the elongation of the implant may be 3.2% to 7%.

[0153] The tensile strength and elongation of the above implant can be measured by manufacturing a specimen having a diameter of 1.5 mm and a length of 50 mm, for example.

[0154] The implant may exhibit a cell viability of 70% or more based on the cell viability of 100% of the dissolution solvent control group in a cytotoxicity test using an extract. In addition, the implant may exhibit a cell viability of 75% or more, 80% or more, or 81% or more based on the cell viability of 100% of the dissolution solvent control group in a cytotoxicity test using an extract. In addition, the implant may exhibit a cell viability of 70% to 90%, 80% to 90%, or 81% to 90% based on the cell viability of 100% of the dissolution solvent control group in a cytotoxicity test using an extract. Specifically, in the cytotoxicity test, after dissolving the implant in an dissolution solvent (e.g., cell culture medium) and treating the dissolution solvent to cells, the cell viability is measured after 48 hours, and the cell viability may be expressed as a relative value when the cell viability of the control group in which only the dissolution solvent is treated to cells is set to 100%.

[0155] In addition, the stiffness of the femur tissue harvested two months after transplanting the implant into the fractured femur tissue of a rat may be 120 N / mm or more. Specifically, the stiffness of the femur tissue harvested two months after transplanting the implant into the fractured femur tissue of a rat may be 130 N / mm or more. For example, the stiffness of the femur tissue harvested two months after transplanting the implant into the fractured femur tissue of a rat may be 120 N / mm to 500 N / mm, 130 N / mm to 500 N / mm, 130 N / mm to 400 N / mm, or 150 N / mm to 300 N / mm.

[0156] Additionally, the stiffness of the femur tissue harvested 4 months after transplanting the implant into the fractured femur tissue of a rat may be 170 N / mm or more. For example, the stiffness of the femur tissue harvested 4 months after transplanting the implant into the fractured femur tissue of a rat may be 170 N / mm to 700 N / mm, 200 N / mm to 600 N / mm, or 250 N / mm to 500 N / mm.

[0157] The stiffness of the femoral tissue can be measured, for example, by a three-point bending test using a biomechanical tester, and can be tested by applying the standards (ASTM F1161, ASTM F382) commonly used for ceramic or fracture plate testing. In one embodiment, the specimen is placed on a test jig with the fracture site positioned on the upper jig in which the gap between the lower support spans is set to 16 mm, and the stiffness can be measured by applying a load of 3 kN at a rate of 5 mm / min until the specimen is broken.

[0158]

[0159] Method for manufacturing implants

[0160] A method for manufacturing an implant according to the present invention comprises the steps of: preparing a biodegradable polymer including a first biodegradable polymer and a second biodegradable polymer; and forming an implant using the biodegradable polymer, wherein the first biodegradable polymer includes a copolymerized polyhydroxyalkanoate (PHA), and the copolymerized polyhydroxyalkanoate (PHA) includes a repeating unit derived from 4-hydroxybutyrate (4-HB) in an amount of 0.1 wt% to 50 wt% based on the total weight of the copolymerized polyhydroxyalkanoate (PHA).

[0161] In one embodiment, the molding may be injection molding.

[0162] The above injection molding may be performed by, for example, extrusion using a twin-screw extruder or single-screw extruder, followed by injection using an injection molding machine, and then post-processing such as annealing. The mold used for the above injection molding may be, for example, a cold runner mold, a hot runner mold, or a pinpoint mold.

[0163] The temperature during the extrusion may be, for example, 100°C to 210°C, the main screw rpm range may be, for example, 100 rpm to 250 rpm, and the feeder rpm range may be, for example, 4 rpm to 40 rpm.

[0164] The temperature during the injection may be, for example, 150°C to 200°C, the injection pressure may be, for example, 1000 bar to 1800 bar, the injection speed may be, for example, 0.5 mm / s to 100 mm / s, the holding pressure range may be, for example, 300 bar to 1200 bar, and the holding pressure time may be, for example, 1 s to 10 s.

[0165] The temperature during the above annealing may be, for example, 80°C to 110°C, and the annealing time may be, for example, 30 minutes to 2 hours.

[0166] In another embodiment, the molding may be a 3D printing molding.

[0167] The printing temperature of the above 3D printing molding may be, for example, 150°C to 200°C, the injection speed may be, for example, 200 mm / min to 400 mm / min, the pressure may be, for example, 200 kPa to 400 kPa, and the printing duration may be performed under conditions of, for example, less than 60 minutes.

[0168] In another embodiment, the implant surface may be modified to enhance cell adhesion and strengthen fixation within tissues.

[0169] In one specific example, after the forming, a step of imparting roughness or a pattern to the surface through blasting, molding, or laser treatment may be additionally included.

[0170] In another specific example, after the forming, a step of imparting hydrophilicity to the surface through plasma treatment may be additionally included.

[0171] In another specific example, after the forming, the step of imparting roughness or a pattern to the surface through blasting, molding, or laser treatment; and the step of imparting hydrophilicity to the surface through plasma treatment may be additionally included.

[0172]

[0173] Composition for implants

[0174] The implant composition according to the present invention comprises a first biodegradable polymer and a second biodegradable polymer, wherein the first biodegradable polymer comprises a copolymerized polyhydroxyalkanoate (PHA), and the copolymerized polyhydroxyalkanoate (PHA) comprises a repeating unit derived from 4-hydroxybutyrate (4-HB) in an amount of 0.1 wt% to 50 wt% based on the total weight of the copolymerized polyhydroxyalkanoate (PHA).

[0175] In one embodiment, the implant composition may comprise a blend of the first biodegradable polymer and the second biodegradable polymer.

[0176] In another embodiment, the copolymerized polyhydroxyalkanoate (PHA) is selected from the group consisting of 2-hydroxybutyrate (2-HB), 3-hydroxybutyrate (3-HB), 3-hydroxypropionate (3-HP), 3-hydroxyvalerate (3-HV), 3-hydroxyhexanoate (3-HH), 3-hydroxyheptanoate (3-Hhep), 3-hydroxyoctanoate (3-HO), 3-hydroxynonanoate (3-HN), 3-hydroxydecanoate (3-HD), 3-hydroxydodecanoate (3-HDd), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV), and 6-hydroxyhexanoate (6-HH). It may further include repeating units derived from one or more selected monomers.

[0177] In another embodiment, the first biodegradable polymer may further comprise one or more polymers selected from the group consisting of poly(3-hydroxybutyrate) (P3HB), poly(4-hydroxybutyrate) (P4HB), poly(3-hydroxyhexanoate) (P3HH), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB-3HH), poly(3-hydroxyoctanoate) (P3HO), and poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) (P3HB-3HO).

[0178] In another embodiment, the second biodegradable polymer is a mixture of one or more selected from synthetic biodegradable polymers and natural biodegradable polymers excluding polyhydroxyalkanoate (PHA), wherein the synthetic biodegradable polymers include polylactic acid (PLA), polycaprolactone (PCL), polyglycolic acid (PGA), poly(lactic acid-co-caprolactone) (PLCL), poly(lactic acid-co-glycolic acid) (PLGA), polybutylene succinate (PBS), and poly(butylene adipate-co-terephthalate) (PBAT); and the natural biodegradable polymers may include starch, silk fibroin, chitosan, chitin, cellulose, collagen, and gelatin.

[0179] In another embodiment, the copolymerized polyhydroxyalkanoate (PHA) may be included in an amount of 10 wt% to 50 wt% based on the total weight of the first biodegradable polymer and the second biodegradable polymer.

[0180] In another embodiment, the implant composition may further comprise one or more additives selected from bioactive glass fibers or ceramics.

[0181] In another embodiment, the composition for implants may further include one or more drugs for enhancing bone regeneration.

[0182] More specific details regarding the first biodegradable polymer, the second biodegradable polymer, the mixing ratio thereof, the content of repeating units derived from 4-hydroxybutyrate (4-HB) in the copolymerized polyhydroxyalkanoate (PHA), the types and contents of the additives and drugs, etc. are as exemplified in the description of the implant above.

[0183] The above implant composition can be used to manufacture an implant according to an embodiment of the present invention, and can be used to manufacture an implant according to the method described above, for example.

[0184]

[0185] The present invention is described in more detail with reference to the following examples. However, the following examples are intended only to illustrate the present invention and the scope of the examples is not limited to these examples.

[0186]

[0187] Examples 1 to 3 and Comparative Example 1: Manufacturing of implants

[0188] Materials and equipment are as follows:

[0189] - PLA: PLLA (BBCA)

[0190] - PHA: P(3HB-4HB) (4-HB 10%, CJ CheilJedang)

[0191] - Extruder (STEER OMEGA 20, Bautech BA 19)

[0192] - Injection molding machine (Engel E-victory 170 / 80)

[0193] Compounding was performed by mixing PLLA and P(3HB-4HB) at different weight ratios as shown in the table below.

[0194] Example 1 Example 2 Example 3 Comparative Example 1P(3HB-4HB)302010-PLLA708090100 Total Content 100100100100

[0195]

[0196] Compounding was performed using the two types of twin screw extruders below.

[0197] BA 19 - Temperature range: 100~170℃, Main screw RPM: 150, Feeder RPM: 7~8, Torque range: 36~42

[0198] Omega 20 - Temperature range: 120~195℃, Main screw RPM: 250, Feeder RPM: 25~35, Torque range: 39~46

[0199] Drying was carried out overnight at 60°C and then at 80°C for 6 hours.

[0200] The injection conditions were temperature: 160~180℃, mold temperature: 30~70℃, pressure: 1100~1500 bar, injection speed: 5~120 mm / s, holding pressure: 300~600 bar, holding pressure time: 3 s, metering amount: 12~15 mm, metering speed: 40 rpm, back pressure: 40 bar, holding pressure switching time: 10 s, and cooling time: 15~30 s.

[0201] As a result, pin-shaped implants with a diameter of 1.5 mm and a length of 50 mm were manufactured in various compositions.

[0202]

[0203] Test Example 1: Strength and Elongation

[0204] The equipment used was a UTM (Instron 34SC-1), and the implant specimens were manufactured in the shape of pins with a diameter of 1.5 mm and a length of 50 mm. The test conditions were a load cell load of 1 kN, a jig distance of 20 mm, and a tensile speed of 20 mm / min. The test results are shown in the table below and Fig. 3.

[0205] Classification Unit Example 1 Example 2 Example 3 Comparative Example 1 Tensile strength MPa 5 6.9 5 6.4 5 8.2 6 1.7 Elongation % 5.0 5.1 5.5 3.1

[0206]

[0207] As can be seen from the test results, Examples 1 to 3 containing 10 to 30 wt% of P(3HB-4HB) have almost no difference in tensile strength compared to Comparative Example 1 containing no P(3HB-4HB) at all, while the elongation increases, imparting flexibility to the material, confirming its suitability as an implant material.

[0208] Additionally, tests were conducted using P(3HB-4HB) (CJ CheilJedang) with various 4HB contents of 6%, 8%, and 10%. Implants were manufactured in the same manner as in Example 1 using P(3HB-4HB) with various copolymer compositions and PLLA at a weight ratio of 3:7. The tensile strength and elongation of the manufactured implants were tested as described above, and the results are shown in the table below.

[0209] P(3HB-4HB) : PLLA = 3 : 7 4HB content in P(3HB-4HB) (%) 6810 Tensile strength (MPa) 61.46 56.88 56.52 Elongation (%) 6.3 16.27 6.11

[0210]

[0211] Test Example 2: Cytotoxicity (in vitro)

[0212] 1) Test method

[0213] Cytotoxicity assessment was conducted based on the "Considerations for Applying GLP to Medical Device Biological Safety Testing (Cytotoxicity Testing Guidelines)" published by the Ministry of Food and Drug Safety, which is based on the international standard ISO 10993-1:12. Based on the guidelines, positive and negative controls, dissolution conditions, and cell lines were used as described below.

[0214] - Positive control: Polyurethane stabilized with organotin

[0215] - Negative control group: High-density polyethylene (standard material for cytotoxicity evaluation)

[0216] - Elution solvent: Cell culture medium (RPMI-1640 + 10% Fetal Bovine Serum + 1% antibiotics)

[0217] - Dissolution conditions: 0.2 g / mL, 37±2℃, 24±2 hours

[0218] - Cell line: WI-38 (human lung fibroblast cell line)

[0219] Cytotoxicity assessment is divided into direct and indirect methods. The direct method is a test that checks for changes in cells by directly contacting the test sample with the cells, and the indirect method is a test that dissolves the test sample in cell culture medium, treats the cells with the dissolved solution, and observes changes in the cells after 48 hours.

[0220] First, cells were seeded into 24-well plates and incubated for 24 hours. Afterwards, 80% confluency was confirmed. For the direct method, test samples were inserted into the plates where cells were being cultured. For the indirect method, the cell culture medium was replaced with the eluate. After 48 hours of incubation, cell changes were observed.

[0221] After 48 hours, the direct method was analyzed using the Live / Dead Cell fluorescent staining method, and the indirect method was analyzed qualitatively by observing cell morphology, followed by quantitative analysis using the WST-1 assay. The analysis was conducted according to guidelines.

[0222] 2) Test results

[0223] The results of Live / Dead Cell fluorescence staining according to the direct method are shown in the table below and Fig. 4. As a result of the test, both Comparative Example 1 and Example 1 containing biodegradable polymers had fewer dead cells than the positive control group and were similar to the negative control group.

[0224] ClassificationNonePositive controlNegative controlComparative example 1 (PLA)Example 1 (PLA 7: PHA 3)ResultNo abnormalityDead cellsConfirmationNo abnormalityNo abnormalityNo abnormality

[0225]

[0226] In addition, the cell morphology after the test according to the indirect method was observed and is shown in Fig. 4. As a result of the test, in Example 1, the cells were attached while maintaining a fibroblast morphology and were seen to have proliferated by more than 80%. In addition, in Comparative Example 1, it was confirmed that the cells proliferated significantly, similar to the negative control group, and filled the culture plate.

[0227] In addition, the cell viability after the test according to the indirect method (WST-1 assay) was measured and shown in Fig. 5. As a result of the test, when the cell viability of the elution solvent control group was set to 100%, Comparative Example 1 (PLA 100%) showed a viability of 80.9%, and Example 1 (PLA / PHA=7:3) showed a viability of 81.1%. According to the Ministry of Food and Drug Safety guideline, a decrease in cell viability of 30% or more is considered cytotoxic, but it was confirmed that Comparative Example 1 and Example 1 both showed no cytotoxicity.

[0228]

[0229] Test Example 3: Induction of osteogenic differentiation (in vitro)

[0230] 1) Test method

[0231] The osteogenic differentiation induction test was conducted using the SaOS-2 cell line (human osteosarcoma cell line) to determine the degree of osteogenic differentiation when the test sample was directly contacted with bone cells. The cell culture medium (bone formation promoting medium) was replaced once every three days, and after two weeks of culture, the degree of osteogenic differentiation was evaluated by performing an Alizarin Red stain to determine whether calcium was produced.

[0232] 2) Test results

[0233] The results of the osteogenic differentiation induction test are shown in Fig. 6. The test results showed that in the first week, Example 1 (PLA / PHA = 7:3) showed slightly more calcium deposition staining than the other groups, indicating that osteogenic differentiation occurred slightly faster than the other groups. However, in the second week, osteogenic differentiation was confirmed to have progressed in all groups without any difference.

[0234]

[0235] Test Example 4: Rat femur fracture (in vivo)

[0236]

[0237] 1) Test method

[0238] An in vivo study was conducted using a PHA-based orthopedic pin-type implant in a rat fracture model. Based on existing literature and previous studies, Sprague-Dawley femurs were osteotomized and implants were inserted. Femur samples from Comparative Example 1 (PLA 100%) and Example 1 (PLA / PHA=7:3) were collected 2 and 4 months after surgery, and histological, radiological, and biomechanical analyses were performed and the results were compared.

[0239] A femur fracture model was conducted in 12-week-old rats, and out of a total of 25 rats, 12 rats were implanted with PLA implants and the remaining 13 rats were implanted with implants of Example 1 (PLA / PHA=7:3) and observed for 4 months as shown in the table below. At 2 months, 3 rats implanted with PLA implants and 3 rats implanted with Example 1 (PLA / PHA=7:3) implants were sacrificed for tissue slide production, and 3 rats implanted with Comparative Example 1 (PLA 100%) implants and 4 rats implanted with Example 1 (PLA / PHA=7:3) implants were sacrificed for Micro CT imaging and femur flexural strength evaluation, and femur tissues were collected from a total of 13 rats. At 4 months, 3 mice with PLA implants and 3 mice with Example 1 (PLA / PHA=7:3) implants were sacrificed for tissue slide production. In addition, 3 mice with PLA implants and 3 mice with Example 1 (PLA / PHA=7:3) implants were sacrificed for micro-CT imaging and femoral flexural strength evaluation, collecting femoral tissues from a total of 12 mice. Afterwards, histopathological, radiological, and biomechanical evaluations were performed through tissue staining, micro-CT imaging, and flexural strength evaluation.

[0240] The model of the rat femur fracture test is described in Fig. 7 and summarized in the table below.

[0241] 0 months 2 months 4 months Comparative Example 1 (PLA 100%) implants were implanted in 12 rats, 6 rats were sacrificed, 6 rats were sacrificed, 3 rats were subjected to histopathological analysis, 3 rats were subjected to radiological and biomechanical analysis, 3 rats were subjected to histopathological analysis, 3 rats were subjected to radiological and biomechanical analysis. Example 1 (PLA / PHA=7:3) implants were implanted in 13 rats, 7 rats were sacrificed, 6 rats were sacrificed, 3 rats were subjected to histopathological analysis, 4 rats were subjected to radiological and biomechanical analysis, 3 rats were subjected to histopathological analysis, 3 rats were subjected to radiological and biomechanical analysis.

[0242]

[0243] Histopathological analysis was performed using H&E staining of femoral specimens to identify basic bone morphology, changes in fracture sites, implant-bone contact surfaces, and new bone formation through microscopic observations. Radiological analysis was performed based on micro CT images to evaluate the degree of femoral bone union. Biomechanical analysis was performed by fixing the femoral specimens in a biomechanical test machine and performing a three-point bending experiment.

[0244] During the pin-type implant of Comparative Example 1 (PLA 100%), a very serious problem occurred in which the pin broke during fixation to the bone, and it was determined that it was difficult to use as a surgical fixation material. In contrast, in Example 1 (PLA / PHA=7:3), the problem that occurred in Comparative Example 1 (PLA 100%) was not present, and thus Example 1 (PLA / PHA=7:3) was confirmed to be more suitable as a surgical implant. In other words, it was confirmed during the surgical process that the physical properties of the pin-type implant of Example 1 (PLA / PHA=7:3) were improved compared to that of Comparative Example 1 (PLA 100%), and thus it was more suitable as a surgical implant.

[0245] None of the 25 rats tested showed any visible signs of inflammation at the wound site, and all survived without significant complications for two and four months, respectively. Femur samples were successfully collected from 25 rats at two and four months post-surgery.

[0246]

[0247] 2) Histopathological evaluation

[0248] Histopathological analysis of the collected femur samples was conducted in the Department of Pathology at Konkuk University. Paraffin blocks and microtome slides were prepared centered on the femoral osteotomy site. Hematoxylin & E (H&E) staining, which facilitates observation of bone matrix arrangement and osteocyte nuclei and cytoplasm, was performed to compare and analyze the progress of bone union between the control and experimental groups. Furthermore, the pin insertion site and contact surface of the femur were examined for foreign body reactions. The results are shown in Figure 8.

[0249] The femur sample collected at 2 months showed H&E staining results showing that Example 1 (PLA / PHA=7:3) had a more regularly organized bone matrix than Comparative Example 1 (PLA 100%), the cytoplasm of bone cells was smaller, and it was spindle-shaped, confirming that Example 1 had progressed in mature bone formation compared to Comparative Example 1.

[0250] In addition, the femur sample collected at 4 months also showed that the bone matrix of Example 1 (PLA / PHA=7:3) was more regularly organized than that of Comparative Example 1 (PLA 100%), the cytoplasm of the bone cells was smaller, and they showed a uniform spindle shape, confirming that Example 1 had progressed in mature bone formation compared to Comparative Example 1.

[0251]

[0252] 3) Radiological analysis

[0253] The radiological analysis of the collected femur samples was conducted with the analysis team of the Osong Medical Industry Promotion Foundation (KBio Health). The radiological analysis was performed using micro CT, and the bony union of the osteotomy surface was confirmed in 2D and 3D images, and the gap of the fracture surface, bone bridge, and hypertrophy patterns were analyzed. In addition, the degree of bony union was analyzed by measuring the quantitative parameter of callus volume and the qualitative parameter of bone marrow density (BMD) in the ROI (range of interest) area of ​​the osteotomy site using micro CT.

[0254] Figure 9 is a 2D / 3D image of a 2-month and 4-month sample, (a) is an image of a sample implanted with Comparative Example 1 (PLA 100%), and (b) is an image of a sample implanted with Example 1 (PLA / PHA=7:3).

[0255] As a result of the 2-month test, a gap in the fracture surface was observed in all three samples of Comparative Example 1 (PLA 100%), and the bone bridge was not observed. In particular, in one sample of Comparative Example 1, displacement of the fracture surface and the pin was observed, confirming that refracture had occurred. In contrast, in Example 1 (PLA / PHA=7:3), a gap in the fracture surface was observed in two out of four samples, and the bone bridge was observed in two samples. In conclusion, in Comparative Example 1, bone union was not achieved in any of the three samples, and in Example 1, bone union was achieved in two out of four samples (50%).

[0256] As a result of the 4-month test, in Comparative Example 1, a gap in the fracture surface was observed in 2 out of 3 samples, and a bone bridge was observed in 1 sample. In Example 1, a gap in the fracture surface was observed in 1 out of 3 samples, and a bone bridge was observed in 2 samples. In conclusion, in Comparative Example 1, bone union was achieved in 1 out of 3 samples, and in Example 1, bone union was achieved in 2 out of 3 samples.

[0257] The results of the radiological analysis of the 2-month sample are shown in the table below and Figures 10a and 10b. The analysis results of the 2-month sample showed no significant difference in callus volume and BMD between Example 1 and Comparative Example 1.

[0258] Comparative Example 1 (PLA 100%) bone volume (mm) 2 )Tissue volume (mm) 3 ) Bone volume / tissue volume (%) BMD (g / cm) 3 )#171.71529.2013.550.4005#274.58529.2014.090.5420#346.21529.208.730.5420Average64.17529.200.120.4900Standard deviation12.750.000.020.0667

[0259] Example 1 (PLA / PHA=7:3) Bone volume (mm) 2 )Tissue volume (mm) 3 ) Bone volume / tissue volume (%) BMD (g / cm) 3 )#176.59529.2014.470.5475#263.31529.2011.960.5190#335.43529.206.690.4619#447.83529.2012.820.5103Average60.79529.200.110.5097Standard deviation15.400.000.030.0308

[0260]

[0261] The results of the radiological analysis of the 4-month sample are shown in the table below and Figures 11a and 11b. As a result of the analysis of the 4-month sample, both the callus volume and BMD were slightly increased in Example 1 compared to Comparative Example 1.

[0262] Comparative Example 1 (PLA 100%) bone volume (mm) 2 )Tissue volume (mm) 3 ) Bone volume / tissue volume (%) BMD (g / cm) 3 )#122.487529.204.20.437#260.059529.2011.30.513#322.487529.204.20.490Mean35.011529.206.620.480Standard deviation17.7120.000.030.032

[0263] Example 1 (PLA / PHA=7:3) Bone volume (mm) 2 )Tissue volume (mm) 3 ) Bone volume / tissue volume (%) BMD (g / cm) 3 )#141.184529.207.80.476#268.929529.2013.00.537#345.963529.208.70.486Average52.025529.209.830.500Standard deviation12.1110.000.020.027

[0264]

[0265] 4) Biomechanical analysis

[0266] The collected femur samples were subjected to a three-point bending test using a biomechanical test machine. The biomechanical properties were evaluated by measuring the stiffness (N / mm), maximum load (N), and maximum deformation (mm) of the samples.

[0267] The three-point bending biomechanical test was conducted with reference to the standards commonly used for testing ceramic or bone plates (ASTM F1161 Standard Test Method for Flexural Strength of Advanced Ceramics at Ambient Temperature, ASTM F382 Standard Specification and Test Method for Metallic Bone Plates).

[0268] The specific test conditions and test methods are as follows.

[0269] - Support span: 16 mm

[0270] - loading rate: 5 mm / min

[0271] - test environment: dry at ambient, room temperature

[0272] - test equipment: MTS Acumen Test system (MTS system Corp. Mn, USA)

[0273] - Load capacity: 3 kN

[0274] - The specimen (animal specimen) was placed on a test jig with the fracture site located on the upper jig and the gap between the lower support spans set to 16 mm. A load of 3 kN was applied to the specimen at a rate of 5 mm / min. The test was conducted until the specimen broke, and the load and displacement values ​​were recorded.

[0275] The biomechanical analysis results of the 2-month sample are shown in the table below. In addition, the stiffness measurement results of the 2-month sample are shown in Fig. 12a.

[0276] Comparative Example 1 (PLA 100%) Stiffness (N / mm) Maximum Load (N) Maximum Strain (mm) #1117.3979.081.42 #2112.3691.821.31 #358.2654.071.91 Average 96.0074.991.55 Standard Deviation 26.7715.680.26

[0277] Example 1 (PLA / PHA=7:3) Stiffness (N / mm) Maximum load (N) Maximum strain (mm) #1132.7188.010.72 #2130.19103.481.10 #3425.79117.050.57 #4137.9695.831.05 Average 206.66101.090.86 Standard deviation 126.5410.710.22

[0278]

[0279] The biomechanical analysis results of the 4-month sample are shown in the table below. In addition, the stiffness measurement results of the 4-month sample are shown in Fig. 12b.

[0280] Comparative Example 1 (PLA 100%) Stiffness (N / mm) Maximum Load (N) Maximum Strain (mm) #1715.05144.880.30 #268.9488.662.07 #3183.09135.830.86 Average 322.36123.121.08 Standard Deviation 281.5624.650.74

[0281] Example 1 (PLA / PHA=7:3) Stiffness (N / mm) Maximum load (N) Maximum deformation (mm) #1617.49211.210.64 #2176.79142.461.36 #3236.02172.861.07 Average 343.43175.511.02 Standard deviation 195.2928.130.30

[0282]

[0283] As a result of biomechanical analysis, Example 1 (PLA / PHA=7:3) was measured to have superior biomechanical strength compared to Comparative Example 1 (PLA 100%) at 2 and 4 months.

Claims

1. Containing a first biodegradable polymer and a second biodegradable polymer, The first biodegradable polymer comprises a copolymerized polyhydroxyalkanoate (PHA), An implant wherein the above copolymerized polyhydroxyalkanoate (PHA) contains repeating units derived from 4-hydroxybutyrate (4-HB) in an amount of 0.1 wt% to 50 wt% based on the total weight of the above copolymerized polyhydroxyalkanoate (PHA).

2. In paragraph 1, An implant comprising a blend of the first biodegradable polymer and the second biodegradable polymer.

3. In paragraph 1, The above implant comprises a central portion and a covering portion, The above covering portion comprises the first biodegradable polymer, An implant wherein the central portion comprises the second biodegradable polymer.

4. In paragraph 1, The above implant comprises a central portion and a covering portion, The central portion and the covering portion each comprise a blend of the first biodegradable polymer and the second biodegradable polymer, An implant wherein the content of the first biodegradable polymer included in the covering portion based on the total weight of the blend included in the covering portion is greater than the content of the first biodegradable polymer included in the central portion based on the total weight of the blend included in the central portion.

5. In paragraph 4, The implant comprises at least one intermediate portion disposed between the central portion and the covering portion, wherein said one or more intermediate portions comprise a blend of said first biodegradable polymer and said second biodegradable polymer, The content of the first biodegradable polymer included in the covering portion based on the total weight of the blend included in the covering portion is greater than the content of the first biodegradable polymer included in the intermediate portion based on the total weight of the blend included in the intermediate portion, An implant wherein the content of the first biodegradable polymer included in the intermediate portion based on the total weight of the blend included in the intermediate portion is greater than the content of the first biodegradable polymer included in the central portion based on the total weight of the blend included in the central portion.

6. In paragraph 1, The above implant An implant having a porous structure including pores with a size of 10 nm to 10 μm.

7. In paragraph 1, The above copolymerized polyhydroxyalkanoate (PHA) is one selected from the group consisting of 2-hydroxybutyrate (2-HB), 3-hydroxybutyrate (3-HB), 3-hydroxypropionate (3-HP), 3-hydroxyvalerate (3-HV), 3-hydroxyhexanoate (3-HH), 3-hydroxyheptanoate (3-Hhep), 3-hydroxyoctanoate (3-HO), 3-hydroxynonanoate (3-HN), 3-hydroxydecanoate (3-HD), 3-hydroxydodecanoate (3-HDd), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV), and 6-hydroxyhexanoate (6-HH). An implant further comprising repeating units derived from the above monomers.

8. In paragraph 1, An implant, wherein the first biodegradable polymer further comprises at least one polymer selected from the group consisting of poly(3-hydroxybutyrate) (P3HB), poly(4-hydroxybutyrate) (P4HB), poly(3-hydroxyhexanoate) (P3HH), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB-3HH), poly(3-hydroxyoctanoate) (P3HO), and poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) (P3HB-3HO).

9. In paragraph 1, The above second biodegradable polymer A mixture of one or more synthetic biodegradable polymers and natural biodegradable polymers excluding polyhydroxyalkanoate (PHA), The above synthetic biodegradable polymers include polylactic acid (PLA), polycaprolactone (PCL), polyglycolic acid (PGA), poly(lactic acid-co-caprolactone) (PLCL), poly(lactic acid-co-glycolic acid) (PLGA), polybutylenesuccinate (PBS), and poly(butyleneadipate-co-terephthalate) (PBAT); The above natural biodegradable polymer is an implant including starch, silk fibroin, chitosan, chitin, cellulose, collagen, and gelatin.

10. In paragraph 1, An implant wherein the copolymerized polyhydroxyalkanoate (PHA) is included in an amount of 10 wt% to 50 wt% based on the total weight of the first biodegradable polymer and the second biodegradable polymer.

11. In paragraph 1, The implant further comprises at least one additive selected from bioactive glass fibers or ceramics.

12. In paragraph 1, The above implant further comprises one or more drugs for enhancing bone regeneration, The above drug or is coated and included on the surface of the above implant, Included in a blend with the first biodegradable polymer and the second biodegradable polymer, or An implant, which is included in a concentration gradient from the surface to the inside of the implant.

13. In paragraph 1, The above implant is An implant having a tensile strength of 40 MPa to 70 MPa and an elongation of 3.2% to 10%, measured by manufacturing a specimen having a diameter of 1.5 mm and a length of 50 mm.

14. In paragraph 1, The above implant is Has a roughness of 1 ㎛ to 10 ㎛ in depth on the surface, or An implant having a grid pattern, wave pattern or stripe pattern with a spacing of 1 ㎛ to 10 ㎛.

15. In paragraph 1, The above implant is An implant that exhibits a cell viability of 70% or more based on the cell viability of 100% of the control group of the dissolution solvent in a cytotoxicity test using the dissolution solvent.

16. In paragraph 1, An implant wherein the stiffness of the femoral tissue harvested two months after transplanting the implant into the fractured femoral tissue of a rat is 120 N / mm or more.

17. A step of preparing a biodegradable polymer comprising a first biodegradable polymer and a second biodegradable polymer; and Comprising a step of forming an implant using the above biodegradable polymer, A method for manufacturing an implant, wherein the first biodegradable polymer comprises a copolymerized polyhydroxyalkanoate (PHA), and the copolymerized polyhydroxyalkanoate (PHA) comprises a repeating unit derived from 4-hydroxybutyrate (4-HB) in an amount of 0.1 wt% to 50 wt% based on the total weight of the copolymerized polyhydroxyalkanoate (PHA).

18. In paragraph 17, A method for manufacturing an implant, wherein the above molding is injection molding or 3D printing molding.

19. In paragraph 18, The above injection molding Extrusion temperature 100℃ to 210℃, Injection temperature 150℃ to 200℃, and A method for manufacturing an implant, performed under conditions of an annealing temperature of 80°C to 110°C.

20. In paragraph 18, The above 3D printing molding Printing temperature 150℃ to 200℃, Injection speed 200 mm / min to 400 mm / min, Pressure 200 kPa to 400 kPa, and A method for manufacturing an implant, performed under the condition that the printing duration is within 60 minutes.

21. In paragraph 17, After the above plastic surgery, A step of imparting roughness or pattern to the surface through blasting, molding, or laser treatment, and Among the steps of imparting hydrophilicity to the surface through plasma treatment, A method for manufacturing an implant, comprising at least one additional surface treatment step.

22. Containing a first biodegradable polymer and a second biodegradable polymer, The first biodegradable polymer comprises a copolymerized polyhydroxyalkanoate (PHA), A composition for implant, wherein the copolymerized polyhydroxyalkanoate (PHA) comprises 0.1 to 50 wt% of a repeating unit derived from 4-hydroxybutyrate (4-HB) based on the total weight of the copolymerized polyhydroxyalkanoate (PHA).

Images