KR20160126117A - Biodegradable triblock copolymers, synthesis methods therefore and microparticles-based drug delivery made there from - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a biodegradable triblock copolymer, a method of synthesizing the biodegradable triblock copolymer, and a microparticle for drug delivery prepared therefrom, and more particularly, to a biodegradable triblock copolymer which is a biodegradable polymer such as polyepsilon -caprolactone- Propylene carbonate-b-epsilon -caprolactone triblock copolymer, PLGA-PPC-PLGA triblock copolymer and poly L-lactide-b-propylene carbonate-bl-lactide triblock copolymer, the triblock copolymers A microparticle for drug delivery prepared from the above triblock copolymers, and a drug delivery system containing the therapeutic drug in the microparticles.
The microparticles can be prepared from a triblock copolymer, which is a carbon dioxide-based biodegradable polymer produced by the synthesis method of the present invention, and the microparticles are applied to a drug delivery system But it can also be useful in various medical fields such as filler and suture.

Description

TECHNICAL FIELD The present invention relates to a biodegradable triblock copolymer, a biodegradable triblock copolymer, a method for synthesizing the biodegradable triblock copolymer, and a drug delivery microparticle prepared from the biodegradable triblock copolymer,

TECHNICAL FIELD The present invention relates to a biodegradable triblock copolymer, a method of synthesizing the biodegradable triblock copolymer, and a microparticle for drug delivery prepared therefrom, and more particularly, to a biodegradable triblock copolymer which is a biodegradable polymer such as polyepsilon -caprolactone- Propylene carbonate-b-epsilon -caprolactone triblock copolymer, PLGA-PPC-PLGA triblock copolymer and poly L-lactide-b-propylene carbonate-bl-lactide triblock copolymer, the triblock copolymers A microparticle for drug delivery prepared from the above triblock copolymers, and a drug delivery system containing the therapeutic drug in the microparticles.

Recently, many mechanisms for effectively delivering drugs to the body have been studied, among which drug delivery systems using nano- and micro-materials have attracted much attention. Carrier materials include microparticles, liposome, micro / nanogel, and emulsion type materials. Among them, drug delivery system using biodegradable polymer microparticle is injected into the body, continuously releasing a certain amount of drug during the treatment period, and can be controlled through the physical properties and surface modification of the polymer. It is also known that it is excellent in biocompatibility and does not generate substances toxic to human body in the decomposition process, and can effectively deliver drugs without being removed by the immune system such as mononuclear phagocytosis system and reticuloendothelial system in the body. The rate of drug release can be controlled by the crystallinity and polarity of the polymer, and many studies are underway to control the crystallinity and polarity of the polymer by controlling the skeleton of the polymer or copolymerization.

A representative biodegradable polymer used in the drug delivery system is poly (ε-caprolactone) (PCL). PCL is a crystalline polyester which is degraded by the hydrolysis mechanism by the penetration of water. It does not generate toxic substances during decomposition and is suitable as a carrier material because of its excellent biocompatibility. In addition, it is a polymer used for biopolymers, surgical sutures, etc. in addition to a drug delivery system because it is relatively easy to process. However, due to its high crystallinity and low hydrophilicity, its degradation rate is low. When used as a drug delivery carrier, it is difficult to penetrate into the particles, resulting in low drug release rate. As a method to overcome this disadvantage, there is a control of the hydrophilic functional group in the polymer chain or copolymerization with other polymers. Generally, PCL is synthesized by ring opening polymerization (ROP) through initiation by OH groups. As a result, it is possible to copolymerize with a polymer having an OH group at the terminal end. Typically, the drug delivery effect is improved by block copolymerization with poly (polyethylene glycol) (PEG).

Poly (propylene carbonate) (PPC) was first synthesized by Inoue in 1969 and is an amorphous poly carbonate synthesized by the copolymerization of CO ₂ and propylene oxide. PPC uses CO ₂ as a monomer and has good decomposition ability in soil and buffer solution and does not generate environmental pollutants during decomposition. For this reason, CO ₂ The problem is presented as a solution to environmental and carbon dioxide regulations in the polymer industry which is highly dependent on oil. However, PPC has not been commercialized yet due to its low thermal properties. It is expected that block copolymer can be formed with the polymer synthesized through ROP by OH group at the end of the PPC chain.

In the present invention, ROP of ε-caprolactone was attempted using PPC as a macroinitiator to compensate for the disadvantage of drug delivery carrier without degrading the biodegradability of PCL. A new structure of carbon dioxide-based biodegradable polymer, poly (ε-caprolactone - b -propylene ethylamine carbonate- b -ε-caprolactone) triblock copolymer . The polymerized triblock copolymers were characterized by DSC, XRD and POM for thermal properties, crystallinity and crystal morphology. Bovine serum albumin (BSA) loaded microparticles were prepared using the W / O / W emulsion technique and the BSA loading efficiency and drug release behavior of various triblock copolymers of [PCL] / [PPC] were measured.

Poly (L-lactide) (PLLA) is a biodegradable polyester synthesized from plants such as corn. It does not generate toxic substances during decomposition and has excellent biocompatibility and is used as biomolecules such as surgical suture or drug delivery carrier. However, due to low hydrophilicity and high crystallinity, it is difficult to penetrate water when used as a drug delivery carrier, resulting in low drug release rate. In order to solve such problems, a method of lowering crystallinity through copolymerization with various polymers or introducing a hydrophilic functional group into a chain has been used. Typically, there is a synthesis of poly (L-lactide-co-glycolide) (PLGA) by copolymerization with poly (glycolide) (PGA). PGA has higher hydrophilicity compared to PLLA and, when copolymerized, decreases the crystallinity of the copolymer and imparts high hydrophilicity. This not only shows a high release rate in the drug delivery system, but also facilitates the penetration of water into the particles and is known to be highly biodegradable. It is also known that it can be processed into various sizes and encapsulate high molecular weight materials. PLGA is synthesized by ring opening polymerization (ROP) by initiation of OH group, and it is possible to copolymerize with polymer having OH group at terminal end. Typical examples are poly (ethylene oxide) (PEO), poly (ethylene glycol) (PEG).

Poly (propylene carbonate) (PPC) is a biodegradable poly carbonate synthesized by using CO ₂ as a monomer. Because PPC uses CO ₂ as a monomer, it can cause global warming due to CO ₂ It is proposed as a solution to environment and CO ₂ regulation in high polymer dependency industry. However, due to its low thermal properties, commercialization is difficult and commercialization has not yet been announced. Since PPC contains an ester group, it is degraded by the hydrolysis mechanism by moisture penetration. It is expected that it can be used as a carrier material which requires high crystallinity and high biodegradability. However, no studies using PPC as a carrier material have been published yet.

In the present invention, random copolymerization of L-lactide and glycolide using PPC as a macroinitiator was attempted to confirm the applicability of PPC synthesized using CO ₂ as a monomer as a drug delivery carrier, and a new structure of CO ₂ -based biodegradable polymer PLGA / PPC / PLGA triblock copolymers were synthesized. The synthesized polymers were characterized by DSC, XRD and POM for thermal properties and crystallinity. Bovine serum albumin (BSA) - loaded microparticles were prepared using the W / O / W emulsion technique and BSA loading efficiency and drug release behavior of various triblock copolymers of PLGA / PPC were measured.

A biodegradable polymer refers to a polymer which is decomposed into a harmless substance to the human body by microorganisms, moisture or light present in the natural world.

Poly (L-lactide) (PLLA) is a polyester compound obtained from plants such as corn and has been actively commercialized. In addition, the biodegradable raw material is the most representative biodegradable raw material having excellent biodegradability and biocompatibility. Recently, the group also reported on the characteristics of L-lactide polymerization using various Al-based compounds. The most common polymerization method of PLLA is ring opening polymerization, and is well known as a method of forming a high molecular weight PLLA chain. Sn (Oct) ₂ is the most excellent catalyst to be used at this time. This is because it is very effective for the production of high molecular weight PLLA as well as stability.

PLLA is a transparent crystalline polymer and is used for medical purposes such as surgical suture and drug delivery materials. However, since the molecular structure is hard due to high crystallinity, when the molded product is manufactured, the impact resistance is weak. In addition, it has a drawback that it is difficult to control the decomposition rate in a drug delivery system due to high crystallinity and low hydrophilicity. As a countermeasure for such drawbacks, a method of introducing a hydrophilic soft segment by a block copolymer and controlling physical properties has been proposed. Currently, many studies have been conducted to increase the degradation rate of polymers and to increase the hydrophilicity of polymers by synthesizing or blending copolymers of PLLA and polyethylene glycol (PEG) by many groups. In addition to the chemical structure, crystallization degree, glass transition temperature, chain flexibility, molecular weight, and the like are known factors that influence the decomposition rate of the polymer. It is known that the lower the molecular weight, the lower the crystallinity, and the more hydrophilic, .

Another environmentally friendly resin used in the present invention to copolymerize with PLLA is polycarbonate with CO ₂ . In addition to research on biodegradable polymers, there is also a growing concern about greenhouse gases, and there is a great deal of effort to reduce CO ₂ in accordance with environmental regulations. As a result, research is being conducted to make polymeric materials from CO ₂ as a raw material. In the polymer industry, which is highly dependent on petroleum, CO ₂ / epoxide copolymerization has attracted much attention in terms of academic and industrial aspects. Poly (propylene carbonate) (PPC), a CO ₂ / PO copolymer using propylene oxide (PO), has a mass ratio of CO ₂ of 44%. In addition, when burned, it is known that environmental pollutants are not generated and the film is excellent in oxygen and moisture barrier properties. Recently, it has attracted attention as a new thermoplastic polymer having biodegradability and has been studied by many researchers.

In the present invention, a triblock copolymer of poly (L-lactide- b- propylene carbonate- b- L-lactide) was synthesized using PPC as a macroinitiator in order to compensate for the physical disadvantages without degrading the biodegradability of PLLA. The synthesized polymer was characterized by GPC, DSC, FT-IR and other polymerization characteristics. Also, the microparticles were prepared from the synthesized polymer.

It is an object of the present invention to provide a biodegradable polymer, poly ε-caprolactone-b-propylene carbonate-b-ε-caprolactone-b-propylene carbonate-b-ε-carprolactone) triblock copolymer a triblock copolymer and a method for producing the same, and a drug delivery system comprising a drug delivery microparticle prepared from the triblock copolymer and a therapeutic drug in the microparticle.

Another object of the present invention is to provide a PLGA-PPC-PLGA triblock copolymer which is a biodegradable polymer and a method for producing the same, a drug delivery microparticle prepared from the triblock copolymer, And to provide a drug delivery system containing a therapeutic drug.

Another object of the present invention is to provide a biodegradable polymer, triblock copolymer (poly-L-lactide-b-propylene carbonate-bL-lactide) ), A method for producing the same, a drug delivery microparticle prepared from the triblock copolymer, and a drug delivery system including the therapeutic drug in the microparticle.

In order to accomplish the above object, the present invention provides a method for producing a polypropylene carbonate (PPC) copolymer comprising a) epoxide compound and carbon dioxide to form a polyoxyethylene (PPC) step; And b) a polypropylene carbonate copolymer having a hydroxyl group at the terminal and an ε-caprolactone monomer in an organic solvent, followed by polymerization under an organometallic catalyst. A method for producing a triblock copolymer (poly (? -Caprolactone-b-ε-carprolactone)) poly ε-caprolactone-b-propylene carbonate-b-ε-carprolactone .

In the present invention, the epoxide compound may be at least one selected from the group consisting of ethylene oxide, propylene oxide, epichlorohydrin, glycidyl ether, glycidol, glycidyl ester, 1,2-butylene oxide, , Cyclopentene oxide, cyclohexene oxide, 3-vinylcyclohexene oxide, cyclooctene oxide, norbornene oxide, and limonene oxide, but is not limited thereto.

In the present invention, the organometallic catalyst may be selected from the group consisting of stannic chloride, stannous oxide, stannous octoate, stannous chloride dihydrate, tetraphenyl tin, Based catalysts including zinc chloride, zinc oxide, zinc octate, and diethyl zinc, which are contained in the exhaust gas of the present invention, But is not limited thereto.

In another aspect, the present invention provides a poly-epsilon -caprolactone-b-propylene carbonate-b-epsilon -caprolactone triblock copolymer produced by the above method.

In yet another aspect, the present invention provides a process for preparing a microparticle formed from a poly-epsilon -caprolactone-b-propylene carbonate-b-epsilon -caprolactone triblock copolymer prepared by the above method, A therapeutically effective amount of one or more therapeutic agents that are included in the pharmaceutical composition.

In the present invention, the therapeutic agent may be at least one selected from the group consisting of an analgesic agent, an anesthetic agent, an arthritic agent, an anti-rheumatic agent, an anti-asthmatic agent, an anticoagulant, an anticonvulsant, an antidepressant, an antidiabetic agent, The composition of the present invention is selected from the group consisting of antiinflammatory agents, antiinflammatory agents, antiinflammatory agents, muscle relaxants, antiparasitic agents, antiviral agents, antifouling agents, antiandrogens, cartilage protecting agents, antiadhesive agents, antitumor cell penetration agents, vasodilators, But are not limited thereto.

Also, the one or more therapeutic agents may be selected from the group consisting of antigens, DNA, RNA and DNA, including peptides, cytokines, growth factors, angiogenic factors, soluble receptors, antibodies and proteins and small molecules, genes, vaccines including fragments and human recombinant proteins thereof Nanoparticles, and nanoparticles, but is not limited thereto.

In the present invention, the microparticle may be a drug delivery system that is applied to an insertable device, and the insertable device may be a stent, a catheter, an airway, a channel, a screw, a plate, a shunt, Joints, artificial heart or valves, and other prosthetic inserts, but are not limited thereto.

According to another aspect of the present invention, there is provided a process for preparing a polypropylene carbonate (PPC) copolymer, comprising the steps of: a) preparing a poly (propylene carbonate) (PPC) copolymer having a hydroxy group at the terminal thereof by polymerization reaction of an epoxide compound and carbon dioxide; And b) a polypropylene carbonate copolymer and a L-lactide ((3S) -cis-3,6-dimethyl-1,4-dioxane-2,5-dione; L-lactide) And a glycolide monomer in an organic solvent to a polymerization reaction under an organometallic catalyst to produce a biodegradable polymer PLGA-PPC-PLGA triblock copolymer. to provide.

In the present invention, the epoxide compound may be at least one selected from the group consisting of ethylene oxide, propylene oxide, epichlorohydrin, glycidyl ether, glycidol, glycidyl ester, 1,2-butylene oxide, , Cyclopentene oxide, cyclohexene oxide, 3-vinylcyclohexene oxide, cyclooctene oxide, norbornene oxide, and limonene oxide, but is not limited thereto.

In the present invention, the organometallic catalyst may be selected from the group consisting of stannic chloride, stannous oxide, stannous octoate, stannous chloride dihydrate, tetraphenyl tin, Based catalysts including zinc chloride, zinc oxide, zinc octate, and diethyl zinc, which are contained in the exhaust gas of the present invention, But is not limited thereto.

In another embodiment, the present invention provides a PLGA-PPC-PLGA triblock copolymer prepared by the above method.

In yet another aspect, the present invention provides a method for the treatment and / or prophylaxis of cancer, comprising administering to a subject a therapeutically effective amount of a microparticle formed from a PLGA-PPC-PLGA triblock copolymer produced by the method and one or more therapeutic agents homogeneously contained in the microparticle, A drug delivery system.

In the present invention, the therapeutic agent may be at least one selected from the group consisting of an analgesic agent, an anesthetic agent, an arthritic agent, an anti-rheumatic agent, an anti-asthmatic agent, an anticoagulant, an anticonvulsant, an antidepressant, an antidiabetic agent, The composition of the present invention is selected from the group consisting of antiinflammatory agents, antiinflammatory agents, antiinflammatory agents, muscle relaxants, antiparasitic agents, antiviral agents, antifouling agents, antiandrogens, cartilage protecting agents, antiadhesive agents, antitumor cell penetration agents, vasodilators, But are not limited thereto.

Also, the one or more therapeutic agents may be selected from the group consisting of antigens, DNA, RNA and DNA, including peptides, cytokines, growth factors, angiogenic factors, soluble receptors, antibodies and proteins and small molecules, genes, vaccines including fragments and human recombinant proteins thereof Nanoparticles, and nanoparticles, but is not limited thereto.

In the present invention, the microparticle may be a drug delivery system that is applied to an insertable device, and the insertable device may be a stent, a catheter, an airway, a channel, a screw, a plate, a shunt, Joints, artificial heart or valves, and other prosthetic inserts, but are not limited thereto.

According to another aspect of the present invention, there is provided a process for preparing a polypropylene carbonate (PPC) copolymer, comprising the steps of: a) preparing a poly (propylene carbonate) (PPC) copolymer having a hydroxy group at the terminal thereof by polymerization reaction of an epoxide compound and carbon dioxide; And b) a polypropylene carbonate copolymer and a L-lactide ((3S) -cis-3,6-dimethyl-1,4-dioxane-2,5-dione; L-lactide) (L-lactide-b-lactide-b-lactide-b-lactide), which is a biodegradable polymer containing a monomer and an organic solvent, propylene carbonate-bL-lactide) triblock copolymer.

In the present invention, the epoxide compound may be at least one selected from the group consisting of ethylene oxide, propylene oxide, epichlorohydrin, glycidyl ether, glycidol, glycidyl ester, 1,2-butylene oxide, , Cyclopentene oxide, cyclohexene oxide, 3-vinylcyclohexene oxide, cyclooctene oxide, norbornene oxide, and limonene oxide, but is not limited thereto.

In the present invention, the organometallic catalyst may be selected from the group consisting of stannic chloride, stannous oxide, stannous octoate, stannous chloride dihydrate, tetraphenyl tin, Based catalysts including zinc chloride, zinc oxide, zinc octate, and diethyl zinc, which are contained in the exhaust gas of the present invention, But is not limited thereto.

In yet another embodiment, the present invention provides a poly L-lactide-b-propylene carbonate-bL-lactide triblock copolymer prepared by the above process.

In another aspect, the present invention relates to a microparticle formed from the poly-L-lactide-b-propylene carbonate-bL-lactide triblock copolymer prepared by the above method and a microparticle formed homogeneously A therapeutically effective amount of at least one therapeutic agent that is at least < RTI ID = 0.0 >

In the present invention, the therapeutic agent may be at least one selected from the group consisting of an analgesic agent, an anesthetic agent, an arthritic agent, an anti-rheumatic agent, an anti-asthmatic agent, an anticoagulant, an anticonvulsant, an antidepressant, an antidiabetic agent, The composition of the present invention is selected from the group consisting of antiinflammatory agents, antiinflammatory agents, antiinflammatory agents, muscle relaxants, antiparasitic agents, antiviral agents, antifouling agents, antiandrogens, cartilage protecting agents, antiadhesive agents, antitumor cell penetration agents, vasodilators, But are not limited thereto.

Also, the one or more therapeutic agents may be selected from the group consisting of antigens, DNA, RNA and DNA, including peptides, cytokines, growth factors, angiogenic factors, soluble receptors, antibodies and proteins and small molecules, genes, vaccines including fragments and human recombinant proteins thereof Nanoparticles, and nanoparticles, but is not limited thereto.

In the present invention, the microparticle may be a drug delivery system that is applied to an insertable device, and the insertable device may be a stent, a catheter, an airway, a channel, a screw, a plate, a shunt, Joints, artificial heart or valves, and other prosthetic inserts, but are not limited thereto.

The microparticles can be prepared from a triblock copolymer, which is a carbon dioxide-based biodegradable polymer produced by the synthesis method of the present invention, and the microparticles are applied to a drug delivery system But it can also be useful in various medical fields such as filler and suture.

1 shows the structure of Co-salen complex 1 of the present invention.
FIG. 2 is a schematic view showing a manufacturing process of a microparticle of the present invention using a water-in-oil-in water (W / O / W) double emulsification technique.
Figure 3 is a schematic representation of PPC (poly (propylene carbonate)) synthesis of the present invention.
4 is a graph showing the results of measurement of PPC molecular weight of the present invention through GPC.
5 is a diagram showing the structure of the synthesized PPC of the present invention analyzed by ¹ H-NMR.
6 is a graph showing the FT-IR spectra of the PPC of the present invention.
7 is a schematic view illustrating a process of synthesizing a poly (ε-caprolactone-b-propylene carbonate-b-ε-caprolactone) triblock copolymer of the present invention.
8 is a graph showing the results of ¹ H-NMR analysis of the synthesized poly (ε-caprolactone-b-propylene carbonate-b-ε-caprolactone) triblock copolymer of the present invention.
9 is a graph showing FT-IR analysis results of the synthesized PCL / PPC / PCL triblock copolymer of the present invention.
10 is a graph showing the gel permeation chromatography (GPC) curve of the PPC of the present invention and the PCL / PPC / PCL triblock copolymer.
11 is a graph showing conversion rates of PCL / PPC / PCL triblock copolymerization according to the molecular weight of PPC.
12 is a graph showing the conversion ratio of PCL / PPC / PCL triblock copolymerization according to the molar ratio of [CL] / [PPC].
13 is a diagram showing the degree of polymerization of PCL according to the molar ratio of [CL] / [PPC].
FIG. 14 is a graph showing crystallinity (X _C ) calculated by [PCL] / [PPC] composition ratio.
Figure 15 shows the XRD (X) of PCL and PCLx '/ PPC ₁₇₉ / PCLx' triblock copolymers (a) PCL and PCLx '/ PPC ₁₁₂ / PCLx' triblock copolymer -ray diffracion) analysis results.
FIG. 16 is a graph showing a result of measurement of crystal growth of PCL / PPC / PCL triblock copolymer over time according to the molar ratio of various [PCL] / [PPC] through POM. (A) is the molar ratio of PCL ₉₀ / PPC ₁₇₉ / PCL ₉₀ , (b) is the molar ratio of PCL ₁₃₀ / PPC ₁₇₉ / PCL ₁₃₀ , (c) is the molar ratio of PCL ₂₇₆ / PPC ₁₇₉ / PCL ₂₇₆ .
17 is a graph showing a result of measurement of crystal growth of PCL / PPC / PCL triblock copolymer over time according to the molar ratio of various [PCL] / [PPC] through POM. (A) is the molar ratio of PCL ₁₄₄ / PPC ₁₁₂ / PCL ₁₄₄ , (b) is the molar ratio of PCL ₂₅₂ / PPC ₁₁₂ / PCL ₂₅₂ , (c) is the molar ratio of PCL ₂₈₄ / PPC ₁₁₂ / PCL ₂₈₄ .
18 is a graph showing a result of measurement of crystal growth of PCL / PPC / PCL triblock copolymer over time according to a molar ratio of various [PCL] / [PPC] through POM. (A) is the molar ratio of PCL ₁₃₃ / PPC ₅₆ / PCL ₁₃₃ , and (b) is the molar ratio of PCL ₂₇₉ / PPC ₅₆ / PCL ₂₇₉ , which is the molar ratio of the various [PCL] / [PPC]
19 is a graph showing the relative crystallinity (X _t ) according to the isothermal crystallization progress time and the PCL / PPC / PCL three-block (1-Xt) versus log t of a triblock copolymer. (A) is the molar ratio of PCLx / PPC ₁₇₉ / PCLx, (b) is the molar ratio of PCLx / PPC ₁₁₂ / PCLx, and (c) PCLx / PPC ₅₆ / PCLx.
FIG. 20 is a diagram showing crystallization rate constants of a PCL / PPC / PCL triblock copolymer. FIG.
21 is a graph showing a crystallization half time of a PCL / PPC / PCL triblock copolymer.
22 is a SEM photograph of (a) microsphere of PCL / PPC / PCL triblock copolymer and (b) PCL microsphere.
Figure 23 is a graph showing the change from microparticles of a PCL / PPC / PCL triblock copolymer to in road, (a) showing the profile of the BSA released in vitro is the _{PCL x / PPC 179 / PCL x} , (b) is a _{PCL x / PPC 112 / PCL x} .
Figure 24 is a graph showing the effect of a PCL _x / PPC ₁₇₉ / PCL _x triblock copolymer (a) and a PCL _x / PPC ₁₁₂ / PCL _x triblock copolymer (a) Figure 5 shows the emission behavior curve.
25 is a graph showing a diffusion coefficient according to a [PCL] / [PPC] composition ratio.
26 schematically shows the synthesis of PPC (poly (propylene carbonate)) of the present invention.
27 is a graph showing the results of measurement of the PPC molecular weight of the present invention through GPC.
28 is a diagram showing the structure of the synthesized PPC of the present invention, analyzed by ¹ H-NMR.
29 is a view showing the FT-IR spectra of the PPC of the present invention.
30 is a schematic view illustrating a process of synthesizing a PLGA / PPC / PLGA triblock copolymer of the present invention.
31 is a graph showing the results of ¹ H-NMR analysis of the synthesized PLGA / PPC / PLGA triblock copolymer of the present invention.
FIG. 32 is a graph showing FT-IR analysis results of the synthesized PLGA / PPC / PLGA triblock copolymer of the present invention. FIG.
33 is a graph showing a gel permeation chromatography (GPC) curve of the PPC and the PLGA / PPC / PLGA triblock copolymer of the present invention.
34 is a diagram showing the conversion ratio of PLGA / PPC / PLGA triblock copolymerization according to the monomer.
35 is a diagram showing the conversion ratio of PLGA / PPC / PLGA triblock copolymerization according to the molecular weight of PPC.
36 is a diagram showing the degree of polymerization of PLGA according to a monomer.
37 is [PLGA] / [PPC] it is a diagram showing the T _g value of the composition ratio (ratio) PLGA / PPC / PLGA triblock copolymer (triblock copolymerization) according to.
38 is a diagram showing the T _g value of [PLA] / [PPC] or [PLGA] / [PPC] PLGA / PPC / PLGA triblock copolymer (triblock copolymerization) in accordance with the composition ratio (ratio).
Figure 39 is a SEM photograph of (a) microsphere of PLGA / PPC / PLGA triblock copolymer and (b) PLLA / PPC / PLLA triblock copolymer microsphere Fig.
Figure 40 is a graphical representation of the microparticles of PLGA / PPC / PLGA triblock copolymer from in road, (a) showing the profile of the BSA in vitro release phase is _{PLGA x / PPC 37 / PLGA x} , (b) is a _{PLLA x / PPC 76 / PLLA x} .
FIG. 41 shows the results of (a) PLGA _x / PPC ₇₆ / PLGA _x triblock copolymer and PLLA _x / PPC ₇₆ / PLLA _x triblock copolymer, (b) PLGA _x / PPC ₃₇ / PLGA _x triblock copolymer. < tb >< TABLE >
FIG. 42 is a view showing a diffusion coefficient according to a composition ratio of [PLGA] / [PPC] or [PLLA] / [PPC].
43 shows the structure of Co-salen complex 1 of the present invention.
44 is a schematic view showing a method of manufacturing a microsphere according to the present invention.
Figure 45 is a schematic representation of PPC (poly (propylene carbonate)) synthesis of the present invention.
46 is a diagram showing the structure of the synthesized PPC of the present invention analyzed by ¹ H-NMR.
47 is a view showing FT-IR spectra of PPC (Mn = 32000 g / mol) of the present invention.
48 is a graph showing the results of measurement of the PPC molecular weight of the present invention by GPC.
49 is a diagram showing a DSC (Differential Scanning Calorimetry) curve of the PPC of the present invention.
50 is a schematic view showing ring-opening polymerization of L-lactide in the presence of dihydroxyl PPC using Sn (Oct) ₂ as a catalyst.
51 is a graph showing the results of ¹ H-NMR analysis of the synthesized poly (L-lactide- b- propylene carbonate- b- L-lactide) triblock copolymer of the present invention.
52 is a view showing FT-IR spectra of synthesized PLLA, PPC and poly (L-lactide- b- propylene carbonate- b- L-lactide) triblock copolymer of the present invention.
FIG. 53 is a graph showing the relationship between the molar ratio of [LA] / [PPC] and the triblock copolymer (A = PLA x '/ PPC ₅₃₀ / PLA x', B = PLA x ' / PPC ₃₉₄ / PLA x ' = PLA x ' / PPC ₃₀₃ / PLA x ", D = PLA x' / PPC ₁₁₇ / PLA x" ).
54 is a graph showing the gel permeation chromatography (GPC) curve of the PPC of the present invention and the poly (L-lactide- b- propylene carbonate- b- L-lactide) triblock copolymer.
55 is a diagram showing a DSC (Differential Scanning Calorimetry) curve of PLLA (Mn = 8700 g / mol) of the present invention.
56 is a diagram showing the structure of the poly (L-lactide- b- propylene carbonate- b- L-lactide) triblock copolymer of the present invention.
57 is a diagram showing the DSC (Differential Scanning Calorimetry) curve of the PPC of the present invention and the poly (L-lactide- b- propylene carbonate- b- L-lactide) triblock copolymer.
FIG. 58 is a diagram showing a change in degree of polymerization according to the difference in PPC chain length and the molar ratio of [LA] / [PPC].
59 is a microsphere SEM photograph of (a) PLLA (Mn = 8700 g / mol) and (b) PPC (Mn = 31000 g / mol).
60 shows a microsphere of (a) PLA ₉₁ / PPC ₁₁₇ / PLA ₉₁ triblock copolymer, (b) PLA ₈₀ / PPC ₃₀₃ / PLA ₈₀ triblock copolymer microspheres (microsphere), (c) PLA ₄₃ / PPC ₅₃₀ / PLA ₄₃ triblock copolymer SEM photograph of a microsphere.
61 is a view schematically showing the difference in evaporation rate depending on the microparticle surface, (a) and (b) show the evaporation rate of the organic solvent according to different polymer structures of the surface, Fig.

Hereinafter, the constitution and effects of the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and the scope of the present invention is not limited by these examples.

Example  One: Poly (竜 - caprolactone -b- 프로로렌 carbonate -b-ε- caprolactone ) Triblock copolymer ( triblock copolymer Synthesis and Drug Release System Studies

Example  1-1: Experimental material

The propylene oxide (PO) used in the synthesis of poly (propylene carbonate) (PPC) was refluxed for 5 h or more in a nitrogen atmosphere with calcium hydride. CO ₂ (Korean industrial gas, 99.999%) was passed through a molecular sieve 3A / 13X (Aldrich) and alumina filling column to remove moisture and oxygen. The catalyst was prepared by using Co-salen catalyst 1 according to the method reported in the literature and its structure is shown in FIG. After the polymerization, silica gel 60 (0.063 ~ 0.200 mm, 70 ~ 230 mesh ASTM) purchased from Merck was used to remove catalyst residues in the copolymer of PO and CO ₂ . The methyl alcohol used for precipitation and the ethyl alcohol used to control the molecular weight of poly (propylene carbonate) to remove the cyclic carbonate and selectivity of poly carbonate were purified by Samchun Chnmicals Co., The monomer ε-caprolactone used in the synthesis of the triblock copolymer was purchased from Aldrich, stirred with calcium hydride for 48 h, vacuum purified, and then the water was removed. The catalyst stannous octoate (Sn (Oct) ₂ ) used in the ROP was purchased from Aldrich and used without purification. In addition, toluene (JT Baker) used as a solvent was refluxed for more than 8 hours by adding sodium / benzophenone under a nitrogen atmosphere and then distilled. Nitrogen gas was passed through Redox Oxygen Removal Tube (Fisher Scientific) and 5A / 13X Molecular Sieve (Aldrich) to remove moisture and oxygen components. After the synthesis of the triblock copolymer, methyl alcohol, chloroform, diethyl ether, and dichloromethane (MC), which were used before refolding, were used without purification by Samchun Chnmicals. The poly (vinyl alcohol) (PVA) , phosphate-buffered salins (PBS), bovine serum albumin (BSA), TWEEN ® 20 , a drug of sodium dodecyl sulfate (SDS) used in the release experiments used Microparticle Preparation, 0.1 M NaOH , and sodium azide was purchased from Aldrich.

Example  1-2: Poly ( 프로로렌 carbonate ) ( PPC ) synthesis

Prior to the synthesis of triblock copolymers, PPC with OH groups at both terminal ends to be used as macroinitiators was synthesized (FIG. 3). The poly (ε-caprolactone-b-propylene carbonate-b-ε-caprolactone)

Specifically, all the polymerization reactions were carried out in a 100 mL high-pressure reactor, and the reactor before the experiment was used for the post-purging experiment. Since the catalyst and PO react sensitively to moisture and oxygen, all experiments were carried out under a nitrogen atmosphere using glove box and schlenk line technology. Catalyst 1 (60 μmol) was added to a flask containing 300 mmol of PO and stirred for 10 minutes. The mixed solution was put into the reactor using a syringe and CO ₂ was replaced three times. The CO ₂ gas was then stirred until 14 bar was maintained. When the CO ₂ pressure was maintained, the gas valve was closed and the temperature was maintained at 40 ° C. At the point when the pressure of CO ₂ began to decrease, polymerization was started and polymerization was carried out for 2 h. After the polymerization, the reactor cooled to room temperature in a cool bath, and the remaining CO ₂ was discharged. The resulting polymer was dissolved in MC and passed through a silica pad prepared in advance to remove the catalyst residue. The product passed through the silica pad was dried in a hood and then vacuum dried in a vacuum oven at 50 ° C for 6 h.

In order to investigate the effect of molecular weight of PPC on the triblock copolymer polymerization, PPC with molecular weight controlled at 18300, 11400 and 5700 g / mol was synthesized with ethanol. The molecular weight of PPC was measured by GPC and the results are shown in Table 1 and FIG.

The structure of the synthesized PPC was analyzed by ¹ H-NMR and the results are shown in FIG. _{^{1 H-NMR (CDCl 3,}} 400.3 MHz, ppm): δ 5.0 (m, 1H, CH (CO 3)), 4.0 ~ 4.2 (m, 2H, CH 2 (CO 3)), 1.34 (d, 3H, CH _3). Figure 6 shows the FT-IR spectra. C = O stretching and CO stretching corresponding to the PPC functional group were observed at 1738 and 1223 cm ^-1 , respectively.

Pp was not amorphous polymer and T _m was not measured. As the molecular weight of polymer increased, T _g was increased.

Example  1-3: Poly (ε- caprolactone -b- 프로로렌 carbonate -b-ε-caprolactone) Three blocks  Copolymer ( triblock copolymer ) synthesis

(Ε-caprolactone-b-propylene carbonate-b-ε-caprolactone) triblock copolymer (ε-caprolactone) was obtained through ring-opening polymerization of ε-caprolactone using PPC of various molecular weights obtained by the polymerization of Example 1-2 as a macroinitiator triblock copolymer.

Specifically, all reactions were performed under nitrogen atmosphere using glove box and schlenk line technology. The polymerization catalyst was selected as Sn (Oct) ₂ , and the solvent was polymerized by toluene solution polymerization. PPC was fixed at 40 μmol and polymerized by changing the molar ratios of [CL] / [PPC] to 300, 600 and 900. In general, ring-opening polymerization using Sn (Oct) ₂ is carried out by the combination of an initiator such as alcohol in which an OH group is present and octanoate, which is a ligand, and the monomer is introduced into the activated catalyst. Polymerization was carried out using a 20-mL glass vial containing a magnetic bar.

PPC and ε-caprolactone obtained in the polymerization of Example 1-2 were added at a predetermined ratio, and then 5 mL of toluene as a solvent and Sn (Oct) ₂ 30 < / RTI > The polymerization temperature was kept constant at 105 ° C in an oil bath and stirred for 3 h. After cooling to room temperature, the polymer was dissolved in chloroform to remove unreacted monomers and homopolymer, and precipitated in cold diethyl ether. The polymer was reprecipitated again with excess amount of cold methanol, separated from the solvent by vacuum filtration, dried at room temperature for one day, and vacuum dried in a vacuum oven for 3 hours to obtain a polymer.

As shown in Fig. 7, PPC having OH groups at both terminal ends was used as a macroinitiator and? -Caprolactone ring-opening polymerization system to synthesize a triblock copolymer by growing a PCL chain at the terminal end of PPC. The results are shown in Table 2 below.

The results of ¹ H-NMR analysis of the synthesized copolymer are shown in FIG. The PCL block peaks of methylene protone (CH ₂ ) in the triblock copolymers were found at 4.08 ppm, 2.3 ppm, 1.6 ppm, and 1.28 ppm, and CH, CH ₂ , CH ₃ Peak at 4.9 ppm, 4.0 ~ 4.2 ppm, and 1.34 ppm, respectively. The triblock copolymer is represented as PCL _{x '} / PPC _y / PCL _{x '} by calculating the degree of polymerization (DP) of the PCL polymerized with both PPC from the ¹ H-NMR spectrum, where x ' , x " y represents the number of repeating units of PCL and PPC in the polymer chain, respectively.

The results of FT-IR analysis of the synthesized triblock copolymer are shown in FIG. PPC in the C = O stretching, peak is 1738, 1223 cm ^-1 indicating the CO stretching, the peak representing the CH stretching in the PCL at ^{2941, 2860 cm -1 C = O} stretching, peak is 1732 cm represents the CO stretching ^{- 1} , 1140 cm ^-1 .

The structure of the polymer synthesized by ¹ H-NMR and FT-IR analysis was analyzed. The molecular weight curve of PPC in the GPC curve was shifted to the higher molecular weight portion as the block copolymerization progressed. triblock copolymer) was synthesized (FIG. 10).

In order to confirm the effect of PPC chain length on triblock copolymerization, homoPCL was synthesized by changing the [CL] / [initiator] molar ratio to 300, 600 and 900 by using benzyl alcohol as an initiator as an initiator.

In the triblock copolymerization, the conversion of PCL was lower than that of PCL homopolymerization, and as the molecular weight of PPC used as a macroinitiator was increased as shown in FIG. 11, the conversion tended to decrease. This seems to be due to the fact that as the PPC chain becomes longer, the contact between the active site and the monomer present in the terminal group becomes difficult due to the steric hindrance of the chain. In addition, the tendency to increase as the molar ratio of [CL] / [PPC] increased, but the conversion rate tended to decrease again when the ratio of [CL] / [PPC] was 600 or more (Fig. 12).

The PCL polymerization degree of the triblock copolymer increased as the amount of CL injected into the polymerization increased as shown in FIG. 13, and the ratio of [CL] / [PPC] The triblock copolymer could be synthesized. Also, it decreases as the molecular weight of the used PPC increases, which is also due to the steric hindrance of the PPC polymer chains for the same reason as the conversion rate.

The following table 4 shows the results of DSC analysis of a triblock copolymer. The amorphous polymer, PPC, showed no T _m at all molecular weights and triblock copolymers showed high T _m as PCL polymerization increased. Also, it can be seen that the T _m is similar to that of PCL as the [PCL] / [PPC] composition ratio increases in the triblock copolymer.

Crystallinity (X _C ) was calculated through ΔH _m and is shown in FIG. Triblock was low as compared with the X is a _C 53 to 30.5 ~ 52.1 homoPCL of the copolymer (Triblock copolymer) was increased together according to [PCL] / [PPC] increase in the composition ratio. X _C is directly related to the crystallinity and it is confirmed that the presence of PPC block in the triblock copolymer reduces the crystallinity of PCL. In addition, the crystallinity of the triblock copolymer could be controlled by synthesizing a copolymer having various [PCL] / [PPC] compositions through various polymerization conditions.

For the crystallization analysis of the additional triblock copolymer, a triblock copolymer synthesized using PPC having a molecular weight of 18600 and 11400 g / mol was subjected to XRD analysis. The ratio of [CL] / [initiator] Is shown in Fig. 15 together with homoPCL results polymerized at 600. As a result, two strong peaks appear at 2 θ = 21.5 ° and 2 θ = 23.8 ° as in homoPCL in all triblock copolymers. The triblock copolymer showed a lower peak than homoPCL and the peak was lowered as the degree of polymerization of PCL in the triblock copolymer decreased. This means that as the DSC results, crystallinity decreases as the amorphous polymer, PPC, is copolymerized with the crystalline PCL.

The crystal growth of the triblock copolymer over time was measured by POM and the results are shown in FIGS. 16, 17 and 18. FIG. At this time, the isothermal temperature was fixed between T _c and T _m . As a result, triblock copolymer synthesized by using PPC having molecular weights of 18300, 11400 and 5800 g / mol as a macroinitiator gradually increased in spherulite form as the ratio of [PCL] / [PPC] Crystal growth morphology of PCL ₉₀ / PCL ₉₀ / PPC ₁₇₉ / PCL ₉₀ showed the disappearance of crystals. In addition, as the [PCL] / [PPC] composition ratio decreased, the time of initial crystal formation and the rate of crystal growth decreased. This was due to the fact that the presence of PPC, an amorphous polymer, inhibited the crystal growth of spherulite form of PCL, This is because the crystallization rate decreases.

In order to confirm the crystallization behavior as a kinetic constant, the relative crystallinity (X _t ) according to the crystallization progress time was measured and measured using a DSC curve, and it was measured and shown in FIG. X _t is calculated by Equation 1, _{d H t} is the enthalpy change with time during the crystallization, and t and ∞ are the elapsed time and the time at which the crystallization ends, respectively, while the crystallization is being performed.

X _t can also be expressed by the Avrami equation and is shown in FIG. 19 through equation (3) expressed as log t and log (-l n (1-X _t )). Here, n is the Avrami index, which indicates the nucleus function and nucleus growth process, and K denotes the rate constant. These values are shown in Table 5 below.

The K value was the highest in PCL ₂₇₉ / PPC ₅₆ / PCL ₂₇₉ synthesized through PPC with 5800 as shown in FIG. 20. As the molecular weight of the PPC used in the polymerization increased, the PCL / PPC composition ratio decreased Respectively. t _1/2 is meant the time required to determine 50% of the growth is complete, and with decreasing the K value, as opposed to a molecular weight of PPC was used for the polymerization, was increased with [PCL] / [PPC] the composition ratio is increased (Fig. 21). This means that as the POM analysis results, the crystal growth rate becomes lower as the ratio of PPC blocks in the triblock copolymer increases.

Theoretically, the n value is an integer between 1 and 4, and it is known that 1-dimensional crystal growth occurs at 1 and spherulite-type crystal growth occurs at 2-4. The n-value of all the triblock copolymers synthesized in the present invention has a value between 3 and 4, which is the same as the crystal growth morphology actually observed with POM. The reason why the value of n is not an integer is that it is impossible to form perfect spherical spherulite crystals due to interference of crystal growth due to contact between spherulite in the crystal growing process.

Example  1-4: Microparticles ( Microparticle ) Produce

(Ε-caprolactone-b-propylene carbonate-b-ε-caprolactone) triblock copolymer was synthesized by using PPC with various molecular weights as a macroinitiator. Through the synthesis of various [PCL] / [PPC] I was able to control sex. Microparticles were prepared using crystallinity controlled PCL / PPC / PCL triblock copolymer and drug release behavior was measured for bovine serum albumin (BSA). In the preparation of microparticles, benzyl alcohol was used as an initiator to confirm the effect of PPC in a block copolymer synthesized by using PPC having a molecular weight of 18300 and 11400 g / mol in a synthesized triblock copolymer. HomoPCL polymerized at a ratio of [CL] / [initiator] of 600 was used.

Specifically, Microparticles were prepared using a water-in-oil-in-water (W / O / W) double emulsification technique (V. Tamboli et al., 2013, Colloid . Polym . Sci . , 291 1235-1245; DR Chen et al., 2000, Polym . Degrad . Stabil . , 67, 455-459). The manufacturing process is shown in Fig. 10 mg of BSA is dissolved in 0.05 mL of PBS (pH 7.4, 0.1 M NaCl) solution and 200 mg of polymer is added to the organic phase dissolved in 15 mL of MC used as an organic solvent. The PVA aqueous solution is prepared by dissolving PVA (1 wt%) and TWEEN ^® 20 (0.02 wt%) in distilled water. Thereafter, the W / O emulsion phase, in which the polymer and BSA were dissolved, was dropped into 200 mL of the PVA aqueous solution by a drop-by-drop method using a 21G needle syringe. Microparticles were obtained by evaporating MC in the organic phase by stirring at room temperature for 3 h at 300 rpm. The microparticles were washed three times with distilled water and dried at room temperature for 24 h.

All microparticles prepared by W / O / W double emulsion technique showed a spherical shape (Fig. 22).

Example  1-5: Drug loading  And In vitro release

The content of BSA in the particles was measured by adding 10 mg of particles to 0.1 M NaOH, 0.5% aqueous solution of SDS, shaking at 37 ° C and 175 rpm for 4 days, and measuring absorbance at 280.1 nm using UV-spectrometer And the amount of drug loading was quantified.

In addition, drug release experiments were performed using TWEEN ^® 50 mg of loaded particles were placed in 4 mL of PBS solution containing 20 (0.5 wt%) and sodium azide (0.01 w / v%) and shaking at 175 rpm at 37 ℃. The drug release was determined by measuring the absorbance at 280.1 nm through a UV-spectrophotomer after a certain period of time (7 days). Release% was calculated by the release concentration / (loading concentration × 5) × 100.

The drug loading and release behavior of Triblock copolymer microparticles against BSA were measured and the results are shown in Table 6 below.

The loading amount was calculated by the following equation (4). The triblock copolymer had a low loading as compared to homoPCL (8.2%) due to low crystallinity, and increased with increasing [PCL] / [PPC] composition ratio Respectively.

Degree 23 shows the drug release profile of the triblock copolymer to BSA. The drug release rate of the triblock copolymer increased with decreasing [PCL] / [PPC] composition ratio in the polymer, which decreased the crystallinity of the polymer due to amorphous PPC in the triblock copolymer And the increase of the free volume thereby facilitates the penetration of moisture into the particles, thereby increasing the drug release rate. In addition, drug release rate of block copolymers is significantly different from homoPCL. This appears to be due to the difference in the polar end groups of the polymer as well as the decrease in crystallinity due to the PPC block in the polymer. In the case of PCL synthesized via benzyl alcohol, there is only one polar end group, whereas the block copolymer is composed of PPC The chain grows in two end groups and has two polar end groups. As a result, the intrinsic polar functional groups are increased and the penetration of moisture into the particles becomes easier.

The experimentally calculated drug release of BSA should consider the time-varying sink condition. Generally, drug release over time in spherical microparticles follows Fick's second law (Equation 5) and curve fitting can be performed using Crank's model (Equation 6).

Where c is the concentration of the drug in the particle, D is the diffusion coefficient, and r is the radius of the particle. Figure 24 shows the drug release behavior curve of a triblock copolymer fitted by Crank's model. The theoretical emissions calculated through the curve fitting can be estimated relatively accurately for the calculated emissions from the experiment, but the initial emissions are high and the latter emissions are low. In the case of PCL / PPC / PCL triblock copolymer, since it is composed of hydrophobic polymer, it is difficult to penetrate the initial moisture, and the amount of release is low. As time passes, hydrolysis of the polymer proceeds, The speed is considered to have increased further.

FIG. 25 shows the diffusion coefficient of PCL / PPC / PCL triblock copolymer calculated using Fick's second law. As the PPC composition ratio in the polymer increases, the diffusion coefficient increases, which appears to be due to a decrease in crystallinity in the polymer.

Example  1-6: Polymer Analysis

Thermal analysis of the resulting triblock copolymer was firstly scanned at a heating rate of 10 ° C / min up to 200 ° C using TA differential scanning calorimetry (TA) (TA 2010) The DSC curve was measured by a second scan at a heating rate of ° C / min, and T _m and T _g were measured. The molecular weight of the resulting polymer was determined by gel permeation chromatography (GPC) from Waters equipped with a pump (Waters 1515), an RI detector (Waters 2414), a column (Shodex KF-804L, Shodex KF-805L) and a sampler Respectively. The mobile phase was tetrahydrofuran (THF, JT Baker, HPLC grade) and the flow rate was 1 mL / min and calibrated using a polystyrene standard (Shodex, SM-105). Image analysis of the particles was performed using a scanning electron microscope (SEM) (FEL company, Nova 230). In order to analyze the crystallinity of polymer according to PPC content, X-ray diffraction (XRD) (Scinco, SMD 3000) was used and the scanning speed was 10 ° / min and the sample interval was 0.05 °. The crystal growth behavior was analyzed by polarized optical microscopy (POM) (U-KPA, BX40). In order to measure the drug loading content and the amount of release, it was analyzed using UV-Visible Spectrometer (Varian, Inc., USA, cary 50 Conc.).

Example  2: PLGA / PPC / PLGA Three blocks  Copolymer ( triblock copolymer Synthesis and Drug Release System Studies

Example 2-1: Experimental material

The propylene oxide (PO) used in the synthesis of poly (propylene carbonate) (PPC) was refluxed for 5 h or more in a nitrogen atmosphere with calcium hydride. CO ₂ (Korean industrial gas, 99.999%) was passed through a molecular sieve 3A / 13X (Aldrich) and alumina filling column to remove moisture and oxygen. Co-salen catalyst 1 was prepared and used in the manner reported in the literature and stored in a glove box. After the polymerization, silica gel 60 (0.063 ~ 0.200 mm, 70 ~ 230 mesh ASTM) purchased from Merck was used to remove catalyst residues in the copolymer of PO and CO ₂ . The methyl alcohol used for precipitation and the ethyl alcohol used to control the molecular weight of PPC to remove the cyclic carbonate by increasing the selectivity of the poly carbonate were used without purification by Samchun chemicals. The monomer (3S) -cis-3,6-dimethyl-1,4-dioxane-2,5-dione (L-lactide) and glycolide used in the synthesis of the triblock copolymer were purchased from Aldrich and used without further purification . The catalyst stannous octoate (Sn (Oct) 2) used in ring opening polymerization was purchased from Aldrich and used without purification. In addition, toluene (JT Baker) used as a solvent was refluxed for more than 8 hours by adding sodium / benzophenone under a nitrogen atmosphere and then distilled. Nitrogen gas was passed through Redox Oxygen Removal Tube (Fisher Scientific) and 5A / 13X Molecular Sieve (Aldrich) to remove moisture and oxygen components. After the synthesis of the triblock copolymer, methyl alcohol, chloroform, diethyl ether and dichloromethane (MC) used for reprecipitation were obtained from Samchun chemicals. Microparticles (Microparticle) used in the manufacturing poly (vinyl alcohol) (PVA) , phosphate-buffered salins (PBS), bovine serum albumin (BSA), a sodium dodecyl sulfate (SDS) used in the TWEEN ^® 20, a drug release experiment , 0.1 M NaOH, and sodium azide was purchased from Aldrich.

Example  2-2: Poly ( 프로로렌 carbonate ) ( PPC ) synthesis

Prior to the synthesis of the PLGA / PPC / PLGA triblock copolymer, PPC was synthesized in which OH groups were present at both terminal ends to be used as macroinitiators (FIG. 26).

Specifically, all the polymerization reactions were carried out in a 100 mL high-pressure reactor, and the reactor before the experiment was used for the post-purging experiment. Since the catalyst and PO react sensitively to moisture and oxygen, all experiments were carried out under a nitrogen atmosphere using glove box and schlenk line technology. Catalyst 1 (60 μmol) was added to a flask containing 300 mmol of PO and stirred for 10 minutes. The mixed solution was put into the reactor using a syringe and CO ₂ was replaced three times. Then CO ₂ The gas was stirred until 14 bar was maintained. CO ₂ When the pressure was maintained, the gas valve was closed and the temperature was maintained at 40 ° C. At the point when the pressure of CO ₂ began to decrease, polymerization was started and polymerization was carried out for 2 h. After the polymerization, the reactor cooled to room temperature in a cool bath, and the remaining CO ₂ was discharged. The resulting polymer was dissolved in MC and passed through a silica pad prepared in advance to remove the catalyst residue. The product passed through the silica pad was dried in a hood and then vacuum dried in a vacuum oven at 50 DEG C for 6 hours.

In order to investigate the effect of molecular weight of PPC on the triblock copolymer polymerization, PPC having molecular weight controlled at 18600, 7800 and 3800 g / mol was synthesized by using ethanol. The molecular weight of PPC was measured by GPC and the results are shown in Table 7 and FIG.

The structure of the synthesized PPC was analyzed by ¹ H-NMR and the results are shown in FIG. _{^{1 H-NMR (CDCl 3,}} 400.3 MHz, ppm): δ 5.0 (m, 1H, CH (CO 3)), 4.0 ~ 4.2 (m, 2H, CH 2 (CO 3)), 1.34 (d, 3H, CH _3). 29 shows the FT-IR spectra. C = O stretching and CO stretching corresponding to the PPC functional group were observed at 1738 and 1223 cm ^-1 , respectively.

Pp was not amorphous polymer and T _m was not measured. As the molecular weight of polymer increased, T _g was increased.

Example  2-3: PLGA / PPC / PLGA Three blocks  Copolymer ( triblock copolymer ) synthesis

A PLGA / PPC / PLGA triblock copolymer was synthesized by random copolymerization of L-lactide and glycolide using PPC of various molecular weights obtained as the macroinitiator obtained in the polymerization of Example 2-2.

Specifically, all reactions were performed under nitrogen atmosphere using glove box and schlenk line technology. The polymerization catalyst was selected as Sn (Oct) ₂ , and the solvent was polymerized by toluene solution polymerization. PPC with molecular weights of 3800, 7800 and 18600 g / mol was used and fixed at 0.5 g. The amount of monomers was changed from 6 to 24 mmol and polymerized. Polymerization was carried out using a 20-mL glass vial containing a magnetic bar.

The PPC obtained in the polymerization of Example 2-2 and the monomers L-lactide and glycolide were added thereto. Then, 5 mL of toluene as a solvent and 30 μmol of a catalyst Sn (Oct) ₂ were added. The polymerization temperature was kept constant at 105 ° C in an oil bath and stirred for 3 h. After cooling to room temperature, the polymer was dissolved in chloroform to remove unreacted monomers and homopolymer, and precipitated in cold diethyl ether. Again, the polymer reprecipitated in an excess of cold methanol was vacuum filtered, separated from the solvent, dried at room temperature for 24 h, and vacuum dried in a vacuum oven for 3 h to obtain a polymer.

The PLGA / PPC / PLGA triblock copolymer is expected to be synthesized through a ring opening polymerization coordination insertion mechanism by the initiation of OH groups present in the short term of PPC, and the mechanism is shown in FIG.

Table 8 below shows the polymerization results of PLGA / PPC / PLGA triblock copolymer.

Copolymer (Triblock copolymer) block three are shown in _{^{1 H-NMR spectrum PLGA x '}} / PPC y / PLGA x'' by calculating a degree of polymerization (DP) of the polymerized PLGA as PPC either side from where x', x " , y means the number of repeating units of PLGA and PPC in the polymer chain, respectively.

The results of ¹ H-NMR analysis of the synthesized copolymer are shown in Fig. The PLGA block peaks CH ₃ , CH ₂ , and CH in the triblock copolymer were 1.40 to 1.52 ppm, 4.7 to 5.0 ppm, 5.11 ppm, 1.6 ppm, and 1.28 ppm, respectively. The peak corresponding to CH3 was 4.9 ppm, 4.0 ~ 4.2 ppm, and 1.34 ppm.

The result of FT-IR analysis of the synthesized triblock copolymer is shown in Fig. C = O stretching, peak showing CO stretching at 1738 and 1223 cm ^-1 , and peak indicating CH stretching at 1452 cm ^-1 .

The structure of the polymer synthesized by ¹ H-NMR and FT-IR analysis was analyzed. From the results of GPC analysis, it was found that the triblock copolymer, which is not a homopolymer, Was synthesized (Fig. 33).

In order to confirm the effect of PPC chain length on triblock copolymerization, the amounts of LA and GA were changed to 6, 12 and 24 mmol by using benzyl alcohol as an initiator. The results are shown in Table 9 below.

The conversion of PCL in triblock copolymerization increased as a large amount of monomers were added as shown in FIG. Also, it showed a lower conversion rate than PLGA polymerization and tended to decrease gradually as the molecular weight of PPC used as macroinitiator increased (Fig. 35). This seems to be due to the fact that as the PPC chain becomes longer, the contact between the active site and the monomer existing in the terminal group becomes difficult due to the steric hindrance of the chain.

The PLGA polymerization degree of the triblock copolymer increased with the increase of the monomers added to the polymerization, and the triblock copolymer having various chain lengths and compositions was synthesized by controlling the [monomer] / [PPC] ratio inputted 36). PLGA _x / PPC ₃₇ / PLGA _x synthesized with PPC having a molecular weight of 3800 g / mol exhibits a lower degree of polymerization than polymers polymerized with higher molecular weight PPC despite high activity. This is because the chain is grown at a higher starting OH compared to PPC at 7800 and 18600 g / mol for PPC having a molecular weight of 3800 g / mol when PPC is added to the reaction at a constant mass during polymerization.

The DSC analysis results of the triblock copolymers are shown in Table 10 below. The triblock copolymers synthesized by block copolymerization of PPC and LA and GA, which were amorphous polymers used in polymerization, did not have T _m . The T _g of the resulting triblock copolymer decreased as the PPC composition ratio in the polymer increased as shown in FIG. 37. The T _g is related to the fluidity and free volume of the polymer, and the flexibility and free volume of the triblock copolymer can be controlled by synthesizing a copolymer of [PLGA] / [PPC] composition ratio. In addition, the fluidity and free volume of the chains in the biodegradable polymer can be increased to enhance the biodegradability by increasing the contact with water and enzyme.

Such as [PLGA] / of PLGA _x / PPC ₃₇ / PLGA _x in [PPC] composition ratio condition T _g is PLGA _x / PPC ₇₆ / higher than PLGA _x, this PLGA _x / PPC ₃₇ / PLGA _x of PLLA in the PLGA block mole fraction is higher than PLGA _x / PPC ₇₆ / PLGA _x .

In order to investigate the effect of PGA in the triblock copolymer on the T _g of the polymer, the amount of L-lactide was adjusted to 6, 12, 24 mmol using PPC having a molecular weight of 7800 g / mol, PLA / PPC / PLA triblock copolymer were synthesized. The results are shown in Table 11 below.

[PPC] and [PLGA] / [PPC] ratios of PLA / PPC / PLA triblock copolymer, PLGA / PPC / PLGA triblock copolymer synthesized under the same conditions in FIG. It showed the amount of change in T _g, triblock the [PPC], [PLGA] / [PPC] ratio of PLA / PPC / PLA triblock copolymer (triblock copolymer) when the same has a higher T _g in the copolymer (triblock copolymer) It looked. This shows that the incorporation of PGA in the PLA chain through random copolymerization reduces the crystallinity of the polymer and thus shows a low T _g .

Example  2-4: Microparticles ( Microparticle ) Produce

PLGA / PPC / PLGA triblock copolymers were synthesized by using PPC as a macroinitiator. Various molecular structures of PLGA / PPC were synthesized and their free volume was controlled. there was. Microparticles were prepared using a PLGA / PPC / PLGA triblock copolymer with various compositions of [PLGA] / [PPC] and the drug release behavior to BSA was measured. In the preparation of microparticles, a block copolymer synthesized by using PPC having a molecular weight of 7800 and 3800 g / mol in a synthesized triblock copolymer was used. In order to confirm the effect of PPC in the polymer, PPC with molecular weight of 7800 g / mol was used to confirm the effect of glycolide in polymerized homoPLGA and triblock copolymer by adding 12, 24 mmol of monomer with benzyl alcohol as initiator Block copolymers were used.

Specifically, microparticles were prepared using a water-in-oil-in-water (W / O / W) double emulsification technique (V.Tamboli et al., 2013, Colloid . Polym. Sci. , 291 5), 1235-1245; Y. Zhuang et al., 2005, Biomaterials , 26, 6736-6742). 10 mg of BSA is dissolved in 0.05 mL of PBS (pH 7.4, 0.1 M NaCl) solution and 200 mg of polymer is added to the organic phase dissolved in 15 mL of MC used as an organic solvent. The PVA aqueous solution is prepared by dissolving PVA (1 wt%) and TWEEN ^® 20 (0.02 wt%) in distilled water. Thereafter, the W / O emulsion phase, in which the polymer and BSA were dissolved, was dropped into 100 mL of PVA aqueous solution using a drop-by-drop method using a 21G needle syringe. Microparticles were obtained by evaporating MC in the organic phase by stirring at room temperature for 3 h at 300 rpm. The microparticles were washed three times with distilled water and dried at room temperature for 24 h.

Most polymer samples were prepared with microparticles loaded with BSA by the W / O / W double emulsion technique. Most of the microparticles were spherical (Fig. 39).

Example  2-5: Drug loading  And In vitro release

The content of BSA in the particles was measured by adding 10 mg of particles to 0.1 M NaOH, 0.5% aqueous solution of SDS, shaking at 37 ° C and 175 rpm for 4 days, and measuring absorbance at 280.1 nm using UV-spectrometer And the amount of drug loading was quantified.

In addition, 50 mg of loaded particles were placed in 4 mL of PBS solution containing TWEEN ^® 20 (0.5 wt%) and sodium azide (0.01 w / v%) and shaking at 175 rpm Respectively. The drug release was determined by measuring the absorbance at 280.1 nm through a UV-spectrophotomer after a certain period of time (7 days). Release% was calculated by the release concentration / (loading concentration × 5) × 100.

The drug loading and release behaviors of Triblock copolymer microparticle to BSA were measured and the results are shown in Table 12 below.

The loading amount of PLGA / PPC / PLGA triblock copolymer was 3.9 ~ 4.1%, which was calculated by Equation (4) of Example 1-5. The loading amount of PLGA / PPC / PLGA triblock copolymer was 3.9 ~ 4.1% PLLA / PPC / PLLA triblock copolymer (4.1 ~ 4.7%) and homoPLGA (5.4%) due to the structure of the particle (paticle). In addition, the amount of loading increased with increasing [PLGA] / [PPC] composition ratio.

Figure 40 shows the drug release profile for BSA of the triblock copolymer. The drug release rate of the triblock copolymer was lower than that of homoPLGA and increased as the ratio of [PLGA] / [PPC] in the polymer decreased.

This is because the presence of PPC in the triblock copolymer reduces the fluidity of the polymer, and the increase of the free volume thereby facilitates the penetration of moisture into the particles, thereby increasing the drug release rate. Also, the drug release rate of PLGA / PPC / PLGA triblock copolymer is higher than that of PLLA / PPC / PLLA triblock copolymer synthesized under the same conditions. This indicates that PGA has a higher hydrophilicity compared to PLA, which increases the relative hydrophilicity within the particle, making it easier to penetrate the inside of the particle.

The experimentally calculated dose of BSA should take into consideration the sink condition where the concentration changes with time. Generally, drug release over time in spherical microparticles follows Fick's second law (Equation 5 of Examples 1-5 above) and curve fitting using Crank's model (Equation 6 of Examples 1-5 above) .

Where c is the concentration of the drug in the particle, D is the diffusion coefficient, and r is the radius of the particle. Figure 41 shows the curves of a triblock copolymer fitted by Crank's model. The theoretical emissions calculated by the curve fitting can be estimated relatively accurately with the experiment, but the initial emissions are higher than the experimental values and the latter emissions are calculated lower. This is a hydrophobic polymer in the case of PLGA / PPC / PLGA triblock copolymer. Since it is difficult to permeate water during initial release, the amount of release is small, and hydrolysis of the polymer progresses with time, Is more likely to increase.

FIG. 42 shows the diffusion coefficient of PLGA / PPC / PLGA triblock copolymer calculated using Fick's second law. The diffusion coefficient of PLGA / PPC / PLGA triblock was calculated higher than PLLA / PPC / PLLA triblock. This seems to be due to the decrease in crystallinity due to PGA insertion in PLGA / PPC / PLGA triblock copolymer. In addition, PLGA _x / PPC ₇₆ / to PLGA compared with _x look low diffusion coefficient, which PLGA _x / PPC ₃₇ / of PLGA _x of PLLA in the PLGA block mole fraction is PLGA _x / PPC ₇₆ for PLGA _x / PPC ₃₇ / PLGA _x / PLGA _x. & Lt _; / RTI >

Example  2-6: Polymer analysis

Thermal analysis of the resulting triblock copolymer was firstly scanned at a heating rate of 10 ° C / min up to 200 ° C using TA differential scanning calorimetry (TA) (TA 2010) The DSC curve was measured by a second scan at a heating rate of ° C / min, and T _m and T _g were measured. The molecular weight of the resulting polymer was determined by gel permeation chromatography (GPC) from Waters equipped with a pump (Waters 1515), an RI detector (Waters 2414), a column (Shodex KF-804L, Shodex KF-805L) and a sampler Respectively. The mobile phase was tetrahydrofuran (THF, JT Baker, HPLC grade) and the flow rate was 1 mL / min and calibrated using a polystyrene standard (Shodex, SM-105). Image analysis of the particles was performed using a scanning electron microscope (SEM) (FEL company, Nova 230). In order to analyze the crystallinity of polymer according to PPC content, X-ray diffraction (XRD) (Scinco, SMD 3000) was used and the scanning speed was 10 ° / min and the sample interval was 0.05 °. The crystal growth behavior was analyzed by polarized optical microscopy (POM) (U-KPA, BX40). In order to measure the drug loading content and the amount of release, it was analyzed using UV-Visible Spectrometer (Varian, Inc., USA, cary 50 Conc.).

Example  3: Poly (L- lactide -b- 프로로렌 carbonate -b-L- lactide ) Synthesis and particle preparation

Example 3-1: Experimental material

The propylene oxide (PO) used in copolymerization was purchased from TCI and used with calcium hydride for 5 hours or more under nitrogen atmosphere. CO ₂ (Korean industrial gas, 99.999%) was passed through a molecular sieve 3A / 13X (Aldrich) and alumina filling column to remove moisture and oxygen. The catalyst was prepared by using Co-salen catalyst 1 according to the method reported in the literature (FIG. 43) and stored in a glove box. In order to remove the catalyst in the copolymer of PO and CO ₂ , silica gel 60 (0.063 ~ 0.200 mm, 70 ~ 230 mesh ASTM) purchased from Merck was used.

The monomer (3S) -cis-3,6-Dimethyl-1,4-dioxane-2,5-dione (L-lactide) used in the synthesis of the triblock copolymer was purchased from Aldrich, It was stored in my cooling box and used without purification. L-lactide and stannous octoate (Sn (Oct) ₂ ) were purchased from Aldrich and used without purification. Further, since the reaction is sensitive to moisture and oxygen, the experiment was conducted in a nitrogen atmosphere. Toluene (JTBaker) used as a solvent was distilled after refluxing for 8 h with sodium / benzophenone under nitrogen. Nitrogen gas was passed through REDOX Oxygen Removal Tube (Fisher) and 5A / 13X Molecular Tube (Aldrich) to remove moisture and oxygen components. After the synthesis of the triblock copolymer, methyl alcohol, chloroform, and diethyl ether, which were used before re-precipitation, were purchased from SAMCHUN and used without purification.

Poly (vinyl alcohol) and TWEEN ^® 20 used in microparticle preparation were purchased from Aldrich.

Example  3-2: Poly ( 프로로렌 carbonate ) ( PPC ) synthesis

In order to synthesize a triblock copolymer of poly (L-lactide- b- propylene carbonate- b- L-lactide), PPC having OH groups at both terminal ends was synthesized (FIG. 45).

Specifically, all the polymerization reactions were carried out in a 100-mL high-pressure reactor, and the reactor was vacuum-cleaned before the experiment. Since the catalyst and propylene oxide (PO) react sensitively to moisture and oxygen, all experiments were conducted under a nitrogen atmosphere using a glove box and a schlenk line. Catalyst 1 (60 μmol) was added to a flask containing PO (300 mmol) and stirred for 10 minutes. The mixed solution was put into the reactor using a syringe and CO ₂ was replaced three times. The stirrer was then agitated until the CO ₂ gas was maintained at 14 bar. When the CO ₂ pressure was maintained, the gas valve was closed and the temperature was maintained at 40 ° C. At the point when the pressure of CO ₂ began to decrease, polymerization was started and polymerization was carried out for 2 h. After the polymerization, the reactor cooled to room temperature in a cool bath, and the remaining CO ₂ was discharged. The resulting polymer was dissolved in MC and then passed through a silica pad prepared in advance to remove the catalyst residue. The product passed through the silica pad was dried in a hood and then vacuum dried in a vacuum oven at 80 DEG C for 5 hours.

Table 13 below shows the molecular weight of PPC measured by GPC. In order to compare the effect of PPC molecular weight on the triblock copolymer polymerization, a polymer controlled at 54000, 40000, 31000 and 12000 g / mol was synthesized.

The structure of synthesized PPC was analyzed by ¹ H-NMR and FT-IR. The polymer used for the analysis is a PPC having a molecular weight of 32000 g / mol. ^The spectrum analyzed by ¹ H-NMR spectra is shown in FIG. The existence of carbonate group of PPC was confirmed by this. _{^{1 H-NMR (CDCl 3,}} 400.3 MHz, ppm): δ 5.0 (m, 1H, CH (CO 3)), 4.0 ~ 4.2 (m, 2H, CH 2 (CO 3)), 1.34 (d, 3H, CH _3). Figure 47 shows FT-IR spectra. A strong absorption signal corresponding to CO, C = O stretching peak represents the adsorption Carbonate unit 1250, 1750 cm ^- was confirmed in ^1.

The GPC curve of the PPC with controlled molecular weight is shown in Fig. A bimodal molecular weight distribution curve appeared in all synthesized PPCs. The portion corresponding to the high molecular weight curve appears to be due to the chain transfer reaction by moisture, as reported in K. Nakano et al . , 2006, Angew . Chem . , 118 (43), 7432-7435 .

The DSC curve is shown in Fig. PPC was an amorphous polymer and T _m was not measured. As the molecular weight increased, T _g increased.

Two OH groups present in both terminal ends of PPC suggest the possibility of a block copolymer with L-lactide.

Example  3-3: Poly (L- lactide -b- 프로로렌 carbonate -b-L- lactide ) synthesis

A triblock copolymer of poly (L-lactide- b- propylene carbonate- b- L-lactide) was synthesized using various chain length PPC as a macroinitiator.

Specifically, all reactions were performed under a nitrogen atmosphere using glove box and Schlenk techniques. The polymerization catalyst was selected as Sn (Oct) ₂ , and the solvent was polymerized by toluene solution polymerization. PPC was fixed at 1 g and polymerized by varying the molar ratio of lactide / PPC ([LA] / [PPC] = 100, 200, 400). In general, the polymerization mechanism using Sn (Oct) ₂ uses an initiator such as alcohol in which an OH group is present. At this time, alcohol is bound to activate octanoate, which is a ligand of Sn (Oct) ₂ , and monomer is inserted between activated catalysts to proceed polymerization. Polymerization was carried out using a 20-mL glass vial containing a magnetic bar.

After adding the PPC and L-lactide obtained in the polymerization of Example 3-2 at a predetermined ratio, 5 mL of toluene as a solvent and the catalyst Sn (Oct) ₂ were added. The polymerization temperature was kept constant at 105 ° C in an oil bath and stirred for 3 h. The polymer was cooled to room temperature and then dissolved in chloroform and precipitated in cold diethyl ether. And reprecipitated in an excess of cold methanol. The precipitated polymer was separated by vacuum filtration and dried at room temperature for one day. Thereafter, the polymer was vacuum dried in a vacuum oven for 1 h to obtain a polymer.

As shown in FIG. 50, a triblock copolymer was prepared by applying a PPC having hydroxyl groups at both terminals to a initiation system of ROP to grow a PLLA polymer chain from OH groups at both terminal ends Were synthesized. Table 14 below shows the polymerization results of the triblock copolymer.

The various triblock copolymers are represented by PLA x ' / PPCy / PLA x' , where the degree of polymerization of PLLA and PPC is given by x ' , x " and y , calculated from the ¹ H-NMR spectrum. Since the OH groups of both end groups of PPC were polymerized under the same chemical environment, it is expected that the triblock copolymer was synthesized by growing PLLA chains at similar rates from both ends.

As a result of ¹ H-NMR analysis of the obtained polymer, the synthesis of a triblock copolymer was confirmed, and a typical spectrum thereof is shown in FIG. The polymer used for the analysis is a triblock copolymer having a molecular weight of 31,000 g / mol of PPC and a molar ratio of [LA] / [PPC] of 200. The major peaks of PLLA were methyl protone (CH ₃ ) and methine protone (CH) at 1.52-1.40 ppm and 5.11 ppm, respectively. Peaks corresponding to -CH, CH ₂ , and CH ₃ in the PPC block were confirmed at 4.9 ppm, 4.0 to 4.2 ppm, and 1.34 ppm, respectively. The molecular weight of the triblock copolymer was calculated by comparing the proton area ratio of CH (δ = 5.11 ppm) peak of PLLA to CH (δ = 4.9 ppm) of PPC. FT-IR spectra of a triblock copolymer are shown in FIG. Specific peaks corresponding to the functional groups of PLLA and PPC were also found in the triblock copolymers. 1250 and 1750 cm ^-1 , respectively, the adsorption peaks of CO and C═O stretching the carbonate unit of PPC were observed. Also in 1750 cm ^-1 carbonyl stretching peak and 1180, 1211 cm of PLLA ^- confirmed the ester COC stretching peak at ^1.

(DP) and the average molecular weight (Mn) of the triblock copolymer were calculated from the ¹ H-NMR spectrum using the following equations (7), (8) and (9) Respectively. Here, reference numerals 102 and 72 represent molecular weights of repeating units of PC (propylene carbonate) and LA (lactide).

As the ratio of [LA] / [PPC] to the PPC of various molecular weights was increased, the molecular weight of the triblock copolymer increased (FIG. 53). This means that the regulation of the molar ratio of [LA] / [PPC] can control the PLLA chain length or degree of polymerization.

The GPC curve is shown in Fig. As the molar ratio of [LA] / [PPC] increases with respect to the PPC of various molecular weights, the bimodal curve shape is maintained and shift phenomenon occurs to the high molecular weight portion. Also, the curve of the inserted PPC is not seen. This indicates that a PLLA chain is grown from the input PPC to form a triblock copolymer. The molecular weight measured by GPC analysis is lower than the molecular weight calculated by ¹ H-NMR analysis. This result is due to the hydrodynamic volume change of the block copolymer compared with the parent homopolymer.

Table 15 below shows the DSC measurement results of the triblock copolymer.

As shown in Figure 55, a typical PLLA is a rigid plastic having a T _g of 50 ° C or higher. On the other hand, the T _g of the triblock copolymer has a value lower than 50 캜. The predicted structure of the triblock copolymer is that the amorphous polymer PPC is present in the middle block and the crystalline polymer PLLA chain is grown on both sides (FIG. 56). This indicates that the presence of the soft segment PPC chain enhances the flexibility and mobility of the triblock copolymer chain. In addition, three blocks of the copolymer (triblock copolymer) T _m was not low or measurement than the PLLA (Figure 57). If the T _m is not measured, the PLLA chain in the triblock copolymer is too short to form a crystal. T _m is related to crystal structure and crystallinity, and the relative length of PPC and PLLA determines the presence of T _m . As the ratio of PLLA / PPC increases, T _m is found and increased. This means that the PPC chain in the triblock copolymer can reduce the crystallinity of PLLA. This property affects the drug release system that uses PLLA as a drug delivery system.

The effect of PPC chain length on LA polymerization degree and triblock copolymer synthesis was investigated. _PPC having a molecular weight of 31000 g / mol (DP _PPC = 303) and 12000 g / mol (DP _PPC = 117) was fixed to the same mole number (0.3 mmol).

Therefore, the amount of OH groups added is the same. As shown in FIG. 58, when the length of the PPC chain is short, the LA polymerization degree is large. This is because short-chain PPC is more likely to react to LA relative to long chains.

Example  3-4: Microparticles ( Microparticle ) Produce

The microparticles of PLLA, PPC and triblock copolymers were synthesized by a single oil-in-water (O / W) emulsification technique.

Specifically, microparticles were prepared using a single oil-in-water emulsification technique (A. Taluja et al. , 2007, J. Mater . Chem. , 17, 4002-4014). The manufacturing process is shown in Fig. Prepare an organic phase by dissolving 200 mg of polymer in 15 mL of dichloromethane (MC), which is an organic solvent. Poly (vinyl alcohol) (PVA) solution is prepared by dissolving PVA (1 wt%) and TWEEN ^® 20 (0.02 wt%) in distilled water. Thereafter, the organic phase, in which the polymer was dissolved, was dripped into 200 mL of the PVA aqueous solution using a 21G needle syringe. Microparticles were obtained by evaporating MC in the organic phase by stirring at room temperature for 3 h at a speed of 300 rpm. The prepared microparticles were washed three times with distilled water and then dried at room temperature for one day. It was then dried in a vacuum oven for 4 h.

A microparticle SEM photograph of the prepared PLLA and PPC is shown in FIG. Particles made of PLLA showed a non-porous spherical shape with a smooth surface. The microparticles made of PPC are also spherical and non-porous. On the other hand, a microparticle of a triblock copolymer is a sponge surface structure in which many holes are present on the particle surface (FIG. 60). This structure is affected by the evaporation rate of the organic solvent in the single O / W emulsification technique. 61, the microparticle of the triblock copolymer was composed of PLLA, which is a crystalline polymer, and PPC, which is an amorphous polymer. Due to this structural difference, the rate of dichloromethane (MC) evaporation in microparticles will be relatively faster in PPC than in the crystalline polymer PLLA (a <b). Thus, during the evaporation of MC at the MC / water interface, the sponge surface structure is obtained due to the difference in the evaporation rate of MC due to the different structures of PPC and PLLA blocks.

PPC and PLLA chain length ratio. 60 (a) shows a PPC / PLLA = 1/2, (b) shows a PPC / PLLA = 2, and (c) shows a chain length ratio of PPC / PLLA = 6. (c) is relatively shorter than the PPC chain length in comparison with (a) and (b). Accordingly, there is little influence of evaporation of MC in the PLLA chain and formation of a porous sponge surface.

Typical PLLA is very low in drug release systems due to its high crystallinity. As the crystallinity is lower, the free volume in the polymer increases, so that drug movement is facilitated and the drug release rate can be rapidly improved. Further, the larger the pores on the surface, the faster the release rate of the drug. As a result of the present invention, microparticles having a sponge surface structure with a high drug release rate were prepared by effectively controlling T _g and T _m using PPC as a soft segment.

Example  3-5: Polymer analysis

The thermal analysis of the polymer was performed by DSC (differential scanning calorimetry) (TA 2010) at a heating rate of 10 ° C / min up to 200 ° C to remove the thermal history, The DSC curve was obtained by a second scan at a heating rate of &lt; RTI ID = 0.0 &gt; C / min &lt; / RTI &gt; to determine melting point and glass transition temperature at the peak position. Molecular weights were analyzed using GPC (gel permeation chromatography) from Waters equipped with a pump (waters 1515), an RI detector (waters 2414), a column (Shodex KF-804L, Shodex KF-805L) and a sampler (waters 717 plus). The calibration curve was prepared using a polystyrene standard (Shodex, SM-105) with tetrahydrofuran (THF, JT Baker, HPLC grade) and a flow rate of 1 mL / min. Structural analysis was performed using an FT-IR spectrometer (Thermo Scientific, Nicholet 6700) and ¹ H-NMR (Bruker Biospin, AVANCE III 400). The solvent used for the analysis was CDCl ₃ . The morphology of the microparticles of the triblock copolymer was observed using a scanning electron microscope (SEM) (MIRA LMH, TESCAN).

Claims (12)

The composition of claim 1 wherein the composition comprises a) at least one compound selected from the group consisting of ethylene oxide, propylene oxide, epichlorohydrin, glycidyl ether, glycidol, glycidyl ester, 1,2-butylene oxide, 2,3-butylene oxide, cyclopentene oxide, , At least one epoxide compound selected from the group consisting of 3-vinylcyclohexene oxide, cyclooctene oxide, norbornene oxide, and limonene oxide, and carbon dioxide are reacted to produce a polypropylene carbonate (Poly propylene carbonate (PPC) copolymer; And
b) polymerizing a mixture of a polypropylene carbonate copolymer and a ε-caprolactone monomer having a hydroxyl group at the terminal thereof in an organic solvent under an organometallic catalyst, and B-propylene carbonate-b-epsilon-carprolactone) triblock copolymer, wherein the poly (? -Caprolactone-b-ε-carprolactone) is a poly (ε-caprolactone-b-ε-carprolactone).
The method of claim 1, wherein the organometallic catalyst is selected from the group consisting of stannic chloride, stannous oxide, stannous octoate, stannous chloride dihydrate, tetraphenyl tin, Or a zinc catalyst comprising zinc chloride, zinc oxide, zinc octate, and diethyl zinc, or a poly-ε catalyst selected from zinc-based catalysts including zinc chloride, zinc oxide, zinc octate, -Caprolactone-b-propylene carbonate-b-epsilon-carprolactone) triblock copolymer. &Lt; RTI ID = 0.0 &
A process for producing a poly-ε-caprolactone-b-propylene carbonate-b-ε-caprolactone-b-propylene carbonate-b-ε-carprolactone triblock copolymer ).
A process for producing a poly (ε-caprolactone-b-propylene carbonate-b-ε-carprolactone) triblock copolymer (b-ε-caprolactone) A microparticle formed from a microparticle; And a therapeutically effective amount of one or more therapeutic agents homogeneously contained within the microparticles.
The composition of claim 1 wherein the composition comprises a) at least one compound selected from the group consisting of ethylene oxide, propylene oxide, epichlorohydrin, glycidyl ether, glycidol, glycidyl ester, 1,2-butylene oxide, 2,3-butylene oxide, cyclopentene oxide, , At least one epoxide compound selected from the group consisting of 3-vinylcyclohexene oxide, cyclooctene oxide, norbornene oxide, and limonene oxide, and carbon dioxide are reacted to produce a polypropylene carbonate (Poly propylene carbonate (PPC) copolymer; And
b) a polypropylene carbonate copolymer containing a hydroxyl group at the terminal and L-lactide ((3S) -cis-3,6-dimethyl-1,4-dioxane-2,5- (PLGA) triblock copolymer, which is a biodegradable polymer, comprising a step of polymerizing a mixture of glycolide monomer and organic solvent in an organic metal catalyst.
6. The method of claim 5, wherein the organometallic catalyst is selected from the group consisting of stannic chloride, stannous oxide, stannous octoate, stannous chloride dihydrate, tetraphenyl tin, Based catalyst or a zinc-based catalyst containing zinc chloride, zinc oxide, zinc octate, and diethyl zinc, or a zeolite-based catalyst containing at least one selected from the group consisting of zinc chloride, zinc oxide, zinc octate, A method of making a PPC-PLGA triblock copolymer.
A PLGA-PPC-PLGA triblock copolymer prepared according to claim 5.
Microparticles formed from the PLGA-PPC-PLGA triblock copolymer prepared according to claim 5; And a therapeutically effective amount of one or more therapeutic agents homogeneously contained within the microparticles.
The composition of claim 1 wherein the composition comprises a) at least one compound selected from the group consisting of ethylene oxide, propylene oxide, epichlorohydrin, glycidyl ether, glycidol, glycidyl ester, 1,2-butylene oxide, 2,3-butylene oxide, cyclopentene oxide, , At least one epoxide compound selected from the group consisting of 3-vinylcyclohexene oxide, cyclooctene oxide, norbornene oxide, and limonene oxide, and carbon dioxide are reacted to produce a polypropylene carbonate (Poly propylene carbonate (PPC) copolymer; And
b) a polypropylene carbonate copolymer containing a hydroxy group at the terminal and a L-lactide ((3S) -cis-3,6-dimethyl-1,4-dioxane-2,5- (L-lactide-b-propylene), which is a biodegradable polymer comprising a poly (lactide-b-propylene carbonate) -b-lactide carbonate-bL-lactide)) triblock copolymer.
The method of claim 9, wherein the organometallic catalyst is selected from the group consisting of stannic chloride, stannous oxide, stannous octoate, stannous chloride dihydrate, tetraphenyl tin, Based catalyst comprising zinc chloride, zinc oxide, zinc octate, and diethyl zinc, or a zinc-based catalyst containing zinc chloride, zinc oxide, diethyl zinc, (L-lactide-b-propylene carbonate-bL-lactide) triblock copolymer.
A triblock copolymer of poly (L-lactide-b-propylene carbonate-bL-lactide) prepared by the process according to claim 9.
A microcapsule formed from a triblock copolymer of poly (L-lactide-b-propylene carbonate-bL-lactide) prepared according to claim 9 Microparticles; And a therapeutically effective amount of one or more therapeutic agents homogeneously contained within the microparticles.

Images