KR20220101914A - A pH-sensitive amphiphilic block copolymer, a manufacturing method thereof, a polymer micelle comprising the pH-sensitive amphiphilic block copolymer - Google Patents

Abstract

The present invention relates to a pH-sensitive amphiphilic block copolymer, a manufacturing method thereof, and a polymeric micelle containing the pH-sensitive amphiphilic block copolymer. More specifically, the present invention can form self-assembled polymeric micelles that can be encapsulated by strong intermolecular hydrophobic interactions of CHGE by copolymerizing hexyloxyethyl glycidyl ether (PCHGE) having hydrophobicity at one end of a hydrophilic polymer, and have excellent stability to the human body. In addition, the polymeric micelles using the same have excellent encapsulation stability and biocompatibility and control the decomposition rate of the micelles by controlling pH or the number of CHGE monomers due to the acetal bond that reacts to the pH of CHGE such that the drug can be effectively released.

Description

A pH-sensitive amphiphilic block copolymer, a manufacturing method thereof, and a polymer micelle comprising the pH-sensitive amphiphilic block copolymer block copolymer}

The present invention relates to a pH-sensitive amphiphilic block copolymer, a method for preparing the same, and a polymer micelle comprising the pH-sensitive amphiphilic block copolymer.

Chemotherapy is the most common means of treating cancer. However, it is of great importance to develop novel drug delivery systems with improved efficiencies to overcome intrinsic limitations of therapeutics such as high toxicity, rapid clearance and tumor selectivity. To solve this problem, research and development on polymer drug carriers including polymer drug conjugates, liposomes, and polymer micelles have been conducted.

Among them, polymer micelles have been widely used and studied as ideal drug delivery carriers with unique advantages such as highly tunable loading efficiency and dose, easy modification, long circulation time in the circulatory system, side effects of release, and tunable degradation kinetics. Although these polymer micelles have made great strides for efficient drug delivery, the stability problem to which they are applied is a challenge to be resolved.

The stability of drug carriers in a biological environment is very important. The adsorption of various protein components in contact with the biological vehicle negatively affects the stability of the vehicle and is a factor that reduces the effectiveness of drug delivery. In addition, the stability of polymer micelles in the bloodstream is reduced due to dynamic equilibrium shift. In order to solve this problem, when non-covalent interactions such as hydrophobicity, electrostatics, host-guest, hydrogen bonding, steric complexes, and coordination interactions are introduced into polymer micelles, the stability of polymer micelles can be improved.

In the existing literature, disulfide-linked cross-linked deoxycholic acid-hyaluronic acid, which is a polymer micelle having a reduction reaction, was synthesized to improve the hydrophobicity of the amphiphilic copolymer. The polymer micelles were degraded in the presence of glutathione and exhibited accelerated hydrophobic drug release. The stearate-g-dextran graft copolymer synthesized in another document has a different grafting degree of hydrophobic stearate. As the ratio of the hydrophobic stearate increases, the loading capacity and encapsulation efficiency increase and the size decreases. In addition, encapsulation of hydrophobic molecules within the amphiphilic assembly is related to hydrophobicity. Accordingly, increasing the hydrophobicity of self-assembled micelle cores may improve interaction with hydrophobic therapeutics and improve loading capacity and efficiency.

In addition, sophisticated delivery is another important element of DDS. Polymeric micelles with specific chemical functional groups that respond to various endogenous stimuli such as pH, redox, enzymes or proteins, nucleic acids have been developed to deliver therapeutic compounds and to control drug release at disease sites. Here, pH-responsive micelles with acid labile bonds such as ketals, acetals, hydrazones and orthoesters esters due to the acidic microenvironment of cancer cells were used.

Synthesis of a series of pH-reactive glycidyl ethers with acetal groups, including tetrahydrofuranyl glycidyl ether (TFGE) and tetrahydropyranyl glycidyl ether (TPGE) as novel functional epoxide monomers for drug delivery did. However, although polymer micelles based on TFGE and TPGE monomers have been successful as drug carriers, achieving high doses and human safety to reduce the side effects of therapeutics remains a challenge.

Korean Patent No. 10-2187144

In order to solve the above problems, an object of the present invention is to provide a pH-sensitive amphiphilic block copolymer capable of forming self-assembled micelles.

Another object of the present invention is to provide a polymer micelle excellent in encapsulation stability and biocompatibility, including the pH-sensitive amphiphilic block copolymer.

Another object of the present invention is to provide a pH-sensitive target delivery system comprising the polymer micelles.

Another object of the present invention is to provide a method for preparing a pH-sensitive amphiphilic block copolymer.

The present invention provides a pH-sensitive amphiphilic block copolymer in which polycyclohexyloxyethyl glycidyl ether (PCHGE) having hydrophobicity at one end of a hydrophilic polymer is copolymerized by anionic ring-opening polymerization.

In addition, the present invention is the pH-sensitive amphiphilic block copolymer; and a molecular imaging marker, contrast agent or therapeutic agent bound to polycyclohexyloxyethyl glycidyl ether (PCHGE) of the pH-sensitive amphiphilic block copolymer.

The present invention also provides a pH-sensitive target delivery system comprising the polymer micelles.

In addition, the present invention comprises the steps of synthesizing cyclohexyloxyethyl glycidyl ether (CHGE); and adding a hydrophilic polymer, the cyclohexyloxyethyl glycidyl ether (CHGE) and a catalyst to an organic solvent, and performing anionic ring-opening polymerization to prepare a pH-sensitive amphiphilic block copolymer; A method for producing a block copolymer is provided.

The pH-sensitive amphiphilic block copolymer according to the present invention can be encapsulated by strong intermolecular hydrophobic interaction of CHGE by copolymerizing polycyclohexyloxyethyl glycidyl ether (PCHGE) having hydrophobicity at one end of the hydrophilic polymer. It can form self-assembled polymer micelles, and has the advantage of excellent human stability.

In addition, the polymer micelles according to the present invention have excellent encapsulation stability and biocompatibility, and control the decomposition rate of micelles by controlling the pH or the number of CHGE monomers due to the acetal bond responding to the pH of CHGE, thereby effectively releasing the drug. can be adjusted so that

The effects of the present invention are not limited to the above-mentioned effects. It should be understood that the effects of the present invention include all effects that can be inferred from the following description.

1 is a 1H NMR spectrum analysis result of the CHGE monomer (a), PCHGE homopolymer (b) and mPEG-b-PCHGE block copolymer (c) prepared in Example 1 and Comparative Example 1 of the present invention.
2 shows the results of MALDI-ToF mass spectrum analysis from 2750 to 4500 Da for the mPEG-b-PCHGE block copolymer prepared in Example 1 of the present invention.
Figure 3 schematically shows the energy diagram (a) of the hydrolysis reaction coordinates of various model acetal side chain compounds (CHPE, TPPE, TFPE, EEPE) and the proposed hydrolysis mechanism (b) of CHPE.
4 is an intensity average hydrodynamic diameter (Dh) distribution diagram (ac) of Cy1, Cy2 and Cy3 micelles prepared in Example 1 of the present invention and AFM images of Cy1, Cy2 and Cy3 micelles with corresponding line scan profiles (df) to be.
5 is an actual image of the encapsulation efficiency (a) of Nile Red and the encapsulation efficiency of Cy1, Cy2 and Cy3 in Cy1, Cy2 and Cy3 of Example 1 of the present invention and E60, P37, and F47 of Comparative Examples 2 to 4 (b) is shown respectively.
6 is a schematic diagram (a) and chemical structure change (b) of a drug release profile based on pyrene fluorescence using Cy1, Cy2, Cy3 prepared in Example 1 of the present invention and E60, P37, and F47 of Comparative Examples 2 to 4 ) and the drug release kinetics (c, d) of micelles using Cy1, Cy2, Cy3 prepared in Example 1 and E60, P37, F47 of Comparative Examples 2 to 4 loaded with pyrene at pH 5.0 and pH 7.4 The results of the analysis are shown.
7 shows the results of FRET-based encapsulation stability analysis in PBS and FBS using fluorescence emission spectra (λex = 450 nm) for Cy1, Cy2, and Cy3 prepared in Example 1 of the present invention.
8 shows the in vitro cell viability assay results determined by MTT assay using HeLa cells for Cy1, Cy2, and Cy3 prepared in Example 1 of the present invention.

Hereinafter, the present invention will be described in more detail by way of an embodiment.

The present invention relates to a pH-sensitive amphiphilic block copolymer, a method for preparing the same, and a polymer micelle comprising the pH-sensitive amphiphilic block copolymer.

The pH-sensitive amphiphilic block copolymer according to the present invention is prepared by copolymerizing polycyclohexyloxyethyl glycidyl ether (PCHGE) having hydrophobicity at one end of a hydrophilic polymer to prepare a pH-sensitive amphiphilic block copolymer. It is possible to form self-assembled polymer micelles that can be encapsulated by strong intermolecular hydrophobic interactions, and has the advantage of excellent human stability. In addition, the amphiphilic block copolymer has excellent loading efficiency due to CHGE having high hydrophobicity. Furthermore, it can be applied to polyether-based bio fields using this.

In addition, the polymer micelles according to the present invention have excellent encapsulation stability and biocompatibility, and control the decomposition rate of micelles by controlling the pH or the number of CHGE monomers due to the acetal bond responding to the pH of CHGE, thereby effectively releasing the drug. can be adjusted so that For example, the polymer micelles can be sustained at 37° C. for up to 14 days to enable sustained release and control of degradation kinetics. In addition, the excellent biocompatibility of the polymer micelles has the advantage of being applicable as a drug delivery carrier.

The present invention provides a pH-sensitive amphiphilic block copolymer in which polycyclohexyloxyethyl glycidyl ether (PCHGE) having hydrophobicity at one end of a hydrophilic polymer is copolymerized by anionic ring-opening polymerization.

The hydrophilic polymer may be a polymer having excellent human body stability, and specific examples include poly(ethylene glycol) methyl ether, polyethylene glycol diacrylate, polyethylene glycol, polyethylene imide, polyamino acid, polymethyl methacrylate, polyethylene oxide, poly It may be at least one selected from the group consisting of vinyl alcohol, polyacrylic acid and polyvinylpyrrolidone. Preferably, it may be at least one selected from the group consisting of poly (ethylene glycol) methyl ether, polyethylene glycol diacrylate, polyethylene glycol and polyethylene oxide, and most preferably poly (ethylene glycol) methyl ether.

Since the polycyclohexyloxyethyl glycidyl ether (PCHGE) contains an epoxy monomer, it has hydrophobicity, and has a characteristic that can be encapsulated by intermolecular hydrophobic interaction. In addition, when forming polymer micelles, various physiologically active ingredients such as pyrene-based organic substances, molecular imaging markers, contrast agents or therapeutic substances are chemically combined with the polycyclohexyloxyethyl glycidyl ether (PCHGE) to be located in the core of the polymer micelles. can

The pH-sensitive amphiphilic block copolymer may be poly(ethylene glycol) methyl ether-block-polycyclohexyloxyethyl glycidyl ether (PEG-b-PCHGE) represented by the following formula (1).

[Formula 1]

) 또는 페닐기(

)이고, 상기 R₂는 CH₃, CH₂CH₃ 또는 -NH₂이고, n과 m은 각 반복단위의 반복수로서, n은 50 내지 200의 정수이고, m은 3 내지 46의 정수이며, n:m은 1: 0.01 내지 1: 0.9이다.)(In Formula 1, R ₁ is hydrogen, an alkyl group having 1 to 4 carbon atoms, a cycle group (

) or a phenyl group (

), wherein R ₂ is CH ₃ , CH ₂ CH ₃ or -NH ₂ , n and m are the number of repeats of each repeating unit, n is an integer of 50 to 200, m is an integer of 3 to 46, n:m is 1: 0.01 to 1: 0.9.)

)이고, n은 70 내지 180의 정수이고, m은 3 내지 46의 정수이며, n:m은 1:0.06 내지 1: 0.7일 수 있다. 더욱 바람직하게는 상기 화학식 1에서, n은 90 내지 160의 정수이고, m은 18 내지 35의 정수이며, n:m은 1:0.1 내지 1: 0.5일 수 있다. 가장 바람직하게는 상기 화학식 1에서, R₁은 사이클기(

)이고, n은 110 내지 120의 정수이고, m은 26 내지 30의 정수이며, n:m은 1:0.2 내지 1: 0.3일 수 있다. 특히, 상기 폴리사이클로헥실옥시에틸글리시딜에테르(PCHGE)의 반복수가 3 미만이면 수평균분자량 및 유리전이온도가 현저하게 저하되고, 소수성 상호작용이 급격하게 떨어져 고분자 마이셀 형성이 어려울 수 있고, 반대로 46 초과이면 마이셀 형성에 사용되는 고분자 양이 적어질 수 있다.Preferably, in Formula 1, R ₁ is a cyclic group (

), n is an integer from 70 to 180, m is an integer from 3 to 46, and n:m may be from 1:0.06 to 1:0.7. More preferably, in Formula 1, n is an integer of 90 to 160, m is an integer of 18 to 35, and n:m may be 1:0.1 to 1:0.5. Most preferably, in Formula 1, R ₁ is a cyclic group (

), n is an integer from 110 to 120, m is an integer from 26 to 30, and n:m may be from 1:0.2 to 1:0.3. In particular, if the number of repetitions of the polycyclohexyloxyethyl glycidyl ether (PCHGE) is less than 3, the number average molecular weight and the glass transition temperature are remarkably reduced, and the hydrophobic interaction is sharply reduced, making it difficult to form polymer micelles, and vice versa. If it exceeds 46, the amount of polymer used to form micelles may be reduced.

The pH-sensitive amphiphilic block copolymer has a number average molecular weight (Mn, _NMR ) of 6,000 to 20,000 g/mol, a molecular weight dispersion (Mw/Mn) of 1.08 to 1.19, and a glass transition temperature (Tg) of -40 to -25 °C. The number average molecular weight may be preferably 6,400 to 14,000 g/mol, more preferably 8,500 to 12,000 g/mol, and most preferably 9,800 to 11,000 g/mol. The molecular weight dispersion may be preferably 1.09 to 1.13, and most preferably 1.1 to 1.12. In addition, the glass transition temperature (Tg) may be preferably -35.3 to -28.6 ℃, most preferably -31 to -29.5 ℃.

At this time, in the pH-sensitive amphiphilic block copolymer, when the number average molecular weight, molecular weight dispersion, and glass transition temperature satisfy all of the above physical property ranges, the average diameter of the polymer micelles is uniformly formed, thereby securing uniform drug loading efficiency. , it is possible to maintain a constant decomposition rate.

The pH-sensitive amphiphilic block copolymer has a critical micelle concentration (CMC) of 1.4 to 13 mg/L, preferably 1.64 to 9.49 mg/L, more preferably 1.91 to 5.24 mg/L, most preferably 2.13 to 2.81 mg/L.

The pH-sensitive amphiphilic block copolymer forms self-assembled micelles when the pH is in the range of 7.2 to 7.6, and the micelles may collapse when the pH is in the range of 1 to 5. The pH-sensitive amphiphilic block copolymer forms stable micelles in the pH range of 7.2 to 7.6, which is the pH range of normal cells in the body, and when the pH is 7.0 or less indicated by abnormal cells such as cancer cells, the micelles are chemically Due to the release of the diagnostic agent bound to the cancer cell target, it can serve as a carrier for drug release of a therapeutic agent for treatment. That is, in an acidic environment where the pH is in the range of 1 to 5, the acetal bond in response to the pH of CHGE in the amphiphilic block copolymer is hydrolyzed to have a double hydrophilic group and the micelles may be collapsed. That is, the pH-sensitive amphiphilic block copolymer can control the decomposition rate of polymer micelles by adjusting the pH.

On the other hand, the present invention is a pH-sensitive amphiphilic block copolymer; and a molecular imaging marker, contrast agent or therapeutic agent bound to polycyclohexyloxyethyl glycidyl ether (PCHGE) of the pH-sensitive amphiphilic block copolymer.

When the polymer micelles are injected into the body, they form micelles, and when the micelles reach a low pH locally, such as cancer cells, the micelles collapse. There is an advantage in that target-directed drug delivery is possible by releasing a therapeutic agent for

The molecular imaging marker is for the diagnosis of diseases, and is pyrene, pyrenebutyric acid, pyrene methylamine, aminopyrene (1-Aminopyrene), pyrene-1-boronic acid (Pyrene-1-boronic). acid), and may be at least one selected from the group consisting of iron oxide and manganese oxide, preferably pyrene.

The therapeutic agent may be one or more selected from the group consisting of peptides, proteins, anticancer agents, anti-inflammatory drugs, antibiotics, antibacterial agents, hormones, genes, and vaccines for the treatment of diseases, but is not limited thereto.

The polymer micelles may have an average diameter of 20 to 200 nm, preferably 26 to 119 nm, more preferably 60 to 105 nm, and most preferably 82 to 87 nm. At this time, if the average diameter of the polymer micelles is less than 20 nm, it may be difficult to support a sufficient amount of drug inside the core. can collapse.

The polymer micelles may be formulated for injection, transdermal or oral administration so as to be administered via oral, transdermal, ocular, subcutaneous, intravenous, intramuscular or intraperitoneal routes, but is not limited thereto.

In addition, the present invention provides a pH-sensitive target delivery system comprising the polymer micelles.

In addition, the present invention comprises the steps of synthesizing cyclohexyloxyethyl glycidyl ether (CHGE); and adding a hydrophilic polymer, the cyclohexyloxyethyl glycidyl ether (CHGE) and a catalyst to an organic solvent, and performing anionic ring-opening polymerization to prepare a pH-sensitive amphiphilic block copolymer; A method for producing a block copolymer is provided.

The step of synthesizing cyclohexyloxyethyl glycidyl ether (CHGE) may be synthesized by adding glycidol and cyclohexyl vinyl ether to a dichloromethane solvent and polymerization.

In the step of preparing the amphiphilic block copolymer, the hydrophilic polymer and cyclohexyloxyethyl glycidyl ether (CHGE) are mixed in a molar ratio of 1: 5 to 60, preferably 1: 10 to 55, more preferably 1: 45 to 50 molar ratio, most preferably 1: 25 to 35 molar ratio may be mixed. In particular, if the cyclohexyloxyethyl glycidyl ether (CHGE) is less than 5 molar ratio, the hydrophobic interaction may be too weak, so it may be difficult to form micelles. can

The catalyst may be at least one selected from the group consisting of t-BuP ₄ , t-BuP ₁ and EtP ₂ , preferably t-BuP ₄ .

In the step of preparing the amphiphilic block copolymer, polymerization is performed at 50 to 100 ° C. for 24 to 72 hours, preferably at 52 to 70 ° C. for 30 to 68 hours, and most preferably at 55 to 65 ° C. for 46 to 50 hours. can In this case, if neither of the polymerization temperature and polymerization time conditions are satisfied, cross-linking between the hydrophilic polymer and CHGE does not occur sufficiently, or thermal and chemical stability of the amphiphilic block copolymer obtained by excessive cross-linking may be reduced. .

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by the following examples.

Example 1

(1) Material

All reagents and solvents were purchased from Sigma-Aldrich, Alfa Aesar or Tokyo Chemical Industry and were used as is unless otherwise specified. Dry toluene and dichloromethane were dried, degassed using a solvent and solvent system (Vacuum Atmospheres, USA), and immediately collected and used. The deuterated NMR solvents CDCl ₃ and D ₂ O were purchased from Cambridge Isotope Laboratories, Inc. CHGE was used for polymerization after drying on molecular sieve 4A.

(2) cyclohexyloxyethyl glycidyl ether (CHGE) monomer synthesis

[Scheme 1]

A solution of glycidol (15.0 g, 0.202 mol) and cyclohexylvinyl ether (17.03 g, 0.135 mol) dissolved in dichloromethane (200 mL) was placed in a round bottom flask and stirred at room temperature for 30 minutes to prepare a mixed solution. To the mixed solution, p-toluene sulfonic acid (0.23 g, 1.35 mmol) was slowly added, and the mixture was stirred at 0° C. for 2 hours. Then, saturated NaHCO ₃ solution was further added, and the mixed solution was stirred for 1 hour. Then, the aqueous phase of the mixed solution was extracted with dichloromethane, and the organic layer was extracted with deionized water.

The obtained organic layer was dried over Na ₂ SO ₄ . The dried organic phase was concentrated under reduced pressure, and the residue was purified by flash column chromatography using ethyl acetate/hexane (1:9 v/v) as an eluent to obtain 22.98 g (85%) of CHGE monomer as a colorless liquid. The CHGE monomer was then further purified by distillation. The successful synthesis of CHGE monomers was confirmed by 1H and 13C NMR, correlation spectroscopy (COSY), heteronuclear single quantum correlation (HSQC), and electrospray ionization mass spectrometry (ESI-MS) (see FIG. 2 below).

1H NMR (400 MHz, CDCl3): δ 4.86 (qd, J = 5.2, 0.6 Hz, 1H), 3.81 (dd, J = 11.3, 3.3 Hz, 1H), 3.69 (dd, J = 11.4, 3.4 Hz, 1H) ), 3.60 - 3.49 (m, 1H), 3.41 (dd, J = 11.3, 6.0 Hz, 1H), 3.18 - 3.09 (m, 1H), 2.83 - 2.76 (m, 1H), 2.64 (dd, J = 5.1) , 2.7 Hz, 1H), 2.60 (dd, J = 5.0, 2.7 Hz, 1H), 1.93 - 1.80 (m, 2H), 1.79 - 1.67 (m, 2H), 1.58 - 1.49 (m, 1H), 1.41 - 1.11 (m, 8H). 13 C NMR (101 MHz, CDCl3): δ 98.14, 98.04, 74.49, 74.34, 65.19, 64.34, 50.94, 50.87, 44.73, 44.60, 33.44, 33.34, 32.65, 32.54, 25.64, 24.39, 24.17, 20.81, 20.58. MS (m/z + Na+, ESI+) calcd for C11H20O3, 223.14; found, 223.13

(3) mPEG-b-PCHGE block copolymer synthesis

[Scheme 2]

(In Scheme 3, n is 114, and m is 10 (Cy1), 30 (Cy2), or 50 (Cy3), respectively.)

The block copolymer was synthesized using poly (ethylene glycol) methyl ether (mPEG) as a macroinitiator. mPEG (1.0 g, 0.2 mmol) was placed in the flask under a flow of nitrogen. Toluene (3.0 mL) was then added to the flask and the mixture was stirred at 70 °C for 30 min. Then 0.25 mL of t-BuP ₄ in n-hexane (0.8 M, 0.2 mmol) was added to the solution. After 30 min CHGE (2.0 g, 10.0 mmol) was added dropwise to the solution using a syringe pump over 6 h. After stirring at 60 °C for 2 days, benzoic acid (0.02 g, 0.2 mmol) was added to terminate polymerization. The reaction mixture was passed through an alumina pad with dichloromethane. The solution was evaporated to dryness to obtain Cy3, respectively (Table 1; 1.98 g) (yield: 71%). The number average molecular weight (Mn) of Cy3 was determined to be 14,000 g/mol as calculated from the NMR data (Fig. 2) using the following equation. In addition, Cy2 was obtained in the same manner as above, except that mPEG (1.0 g, 0.2 mmol) and CHGE (1.2 g, 6.0 mmol) were mixed. In addition, Cy1 was obtained in the same manner as above, except that mPEG (1.0 g, 0.2 mmol) and CHGE (0.4 g, 2.0 mmol) were mixed.

number of repeat units (CHGE) = 45 (integral value of methine peak, 45H, 4.80 ppm and methyl, 3H, 3.38 ppm of mPEG); Mn = (200.28 g/mol (molecular weight of CHGE monomer) x 45 (number of repeat units)) + 5000 g/mol (molecular weight of mPEG) = 14012 g/mol. Considering the error range of NMR integration, 14000 g/mol was used as the Mn value of Cy3.

1H NMR (400MHz, CDCl3) δ 4.85 - 4.74 (m, 45H), 3.96 - 3.40 (m, 734H), 3.39 (s, 3H), 1.86 (s, 94H), 1.73 (s, 92H), 1.61 - 1.47 (m, 44H), 1.42 - 1.09 (m, 385H).

Comparative Example 1

(3) PCHGE homopolymer synthesis

[Scheme 3]

(In Scheme 3, n is 25 or 50.)

A 0.125 mL solution of t-BuP ₄ (0.80 M, 0.1 mmol) in n-hexane was added to a solution of benzyl alcohol (10.4 μL, 0.1 mmol) in toluene under a nitrogen atmosphere. Then CHGE (1.0 g, 5 mmol) was added dropwise to the solution with a syringe pump to polymerize over 6 hours. After stirring at room temperature for 24 hours, polymerization was stopped by addition of benzoic acid (12.2 mg, 0.1 mmol). Then, after quenching, the obtained polymer was passed through an alumina pad using dichloromethane. Then, the polymer was evaporated to dryness to obtain PCHGE (500 mg) (yield: 50%). The number average molecular weight of PCHGE ₅₀ (Table 1) was 10100 g/mol as calculated from the NMR data shown in FIG. 2 using the following equation.

number of repeat units (CHGE) = 50 (integral value of methine peak, 50H, 4.78 ppm and methylene of benzyl alcohol, 2H, 4.53 ppm); Mn = (200.28 g/mol (molecular weight of CHGE monomer) X 50 (number of repeat units)) + 108.14 g/mol (molecular weight of benzyl alcohol) = 10122.14 g/mol. Considering the error range of the NMR integration, the Mn value of PCHGE ₅₀ was 10100 g/mol. PCHGE ₂₅ was obtained in the same manner as above, except that CHGE (0.5 g, 2.5 mmol) was mixed.

1H NMR (400MHz, CDCl3): δ 4.79 (dd, J = 10.1, 6.4Hz, 50H), 4.54 (s, 2H), 3.78 - 3.34 (m, 312H), 1.84 (s, 105H), 1.72 (s) 109H), 1.52 (d, J = 7.1 Hz, 53H), 1.40 - 1.07 (m, 438H).

Comparative Examples 2 to 4

Blocks of commercially available mPEG ₁₁₄ -b-PCHGE ₆₀ (Comparative Example 2, E60), mPEG ₁₁₄ -b-PCHGE ₃₇ (Comparative Example 3, P37) and mPEG ₁₁₄ -b-PCHGE ₄₇ (Comparative Example 4, F47) Each copolymer was prepared.

Experimental Example 1: NMR spectrum analysis

1H NMR spectra of the CHGE monomer, mPEG-b-PCHGE block copolymer, and PCHGE homopolymer prepared in Example 1 and Comparative Example 1, respectively, were analyzed, and the results are shown in FIG. 1 .

1 is a 1H NMR spectrum analysis result of the CHGE monomer (a), PCHGE homopolymer (b) and mPEG-b-PCHGE block copolymer (c) prepared in Example 1 and Comparative Example 1. FIG. Referring to FIG. 1, in the case of the PCHGE homopolymer (b) of Comparative Example 1, it was shown that the monomer was converted into a polymer by the disappearance of a and b, which are the epoxide peaks of the monomer at 2.60, 2.80 and 3.15 ppm. Also benzyl protons (x; 4.52 to 4.55 ppm), polyether backbone protons (a, b and c; 3.40 to 3.75 ppm), methine protons (d; 4.75 to 4.85 ppm), and methyl and cyclohexyloxy protons (eg : g, h and i, 1.10 to 1.90 ppm), it was confirmed that other peaks of the PCHGE homopolymer were clearly displayed. The theoretical number average molecular weight (Mn, NMR) was calculated as the integral ratio of benzylic protons and methine protons in the 1H NMR spectrum.

Also, referring to FIG. 1(c), the 1H NMR spectrum of the mPEG-b-PCHGE block copolymer clearly showed each characteristic peak according to the structure: methyl proton (x; 3.38 ppm) of the mPEG macroinitiator. , methine protons (d; 4.75 to 4.80 ppm), polyether backbone protons (y, z; 3.40 to 3.75 ppm), methyl and cyclohexyloxy protons (eg g, h and i; 1.10 to 1.90 ppm). The degree of polymerization (DP) of the amphiphilic block copolymer was determined by the ratio of the methine peak of CHGE (g; 4.75 to 4.80 ppm) and the methine peak of mPEG (3.38 ppm). Although not specified in Experimental Example 1, the GPC results of the mPEG-b-PCHGE block copolymer showed a single mode distribution with a narrow dispersion (D <1.13) in all items.

Experimental Example 2: Analysis of Mn, Tg and CMC properties

Number average molecular weight (Mn), glass transition temperature (Tg) and critical micelle concentration (CMC) for the CHGE monomer, mPEG-b-PCHGE block copolymer, and PCHGE homopolymer prepared in Example 1 and Comparative Examples 1 to 4, respectively ) was measured. The results are shown in Table 1.

[How to measure]

Number average molecular weight (Mn) was determined by b1H NMR spectroscopy, cGPC (THF, RI signal, PMMA standard) and dGPC (DMF, RI signal, PMMA standard).

The glass transition temperature (Tg) was measured at a rate of 10 °C/min by differential scanning calorimetry (DSC). Critical micelle concentration (CMC) values were calculated by fluorescence spectroscopy using pyrene as a probe.

Since the critical micelle concentration (CMC) is the minimum micelle-forming polymer concentration for micelle formation and is an important parameter predicting the stability of micelles, the CMC value of the amphiphilic block copolymer was measured using pyrene as a fluorescent probe. The specific photoluminescence of pyrene when pyrene is close to each other, such as the hydrophobic core of self-assembled polymer micelles, was plotted according to various concentrations of each polymer in the ratio I339/I332 (intensity of 339 at 332 nm). A specific method for measuring critical micelle concentration (MC) using pyrene fluorescence was prepared by preparing polymer solutions in dimethylformamide (DMF) at various concentrations (0.001 mg/L to 1000 mg/L). To the mPEG-b-PCHGE block copolymer solution was added 10 μl of pyrene solution (5.2 mg/L in DMF) and the mixture was stirred at room temperature for 30 minutes. A total of 5 mL of deionized water was then added to the solution using a syringe pump at a rate of 0.5 mL/min. The solution was allowed to equilibrate overnight. The fluorescence of each pyrene-containing polymeric micellar solution (different concentrations) was measured at an emission wavelength of 372 nm using a fluorometer in a 1 x 1 cm quartz cell. The following parameters were selected. Emission wavelength = 372 nm, excitation wavelength range = 300 - 360 nm, data interval = 0.5 nm. The ratio of fluorescence intensity at wavelengths of 339 and 332 nm was plotted against polymer concentration and CMC was determined at the inflection point.

According to the results in Table 1, the polymerization conversion of each composition was 99% or more. In the case of Example 1, it was confirmed that the number average molecular weight (Mn, _NMR ) increased as the number of CHGE increased. In addition, the CMC values of Example 1 were 9.49 ± 2.61 (Cy1), 2.47 ± 0.34 (Cy2), and 1.64 ± 0.18 mg/L (Cy3), respectively. That is, the CMC value of the amphiphilic block copolymer decreased as the number of hydrophobic blocks increased. In particular, in the case of Cy2, it was found that the loading efficiency of the critical micelle concentration was the best compared to the number of CHGE monomers. In addition, in Comparative Examples 2 to 4, the number average molecular weight (Mn, _NMR ) was relatively low compared to Cy2 and Cy3 of Example 1, and in the CMC value, E60 of EEGE and TPGE (10.3 mg/L) ), P37 (9.79 mg/L) and F47 (113.6 mg/L), which were confirmed to be higher than those of Cy2 and Cy3 of Example 1. Through this, in the case of Example 1, it was found that the CMC value was relatively lower than that of Comparative Examples 2 to 4, indicating that the hydrophobicity of the CHGE monomer was large.

On the other hand, the glass transition temperature (Tg) increased from -36.8 °C to -31.5 °C as the polymerization degree of CHGE in the PCHGE homopolymer of Comparative Example 1 increased. From these results, it was found that the more the chair-to-chair stacks of the cyclohexyl group of CHGE were, the higher the Tg value could be. Similarly, in the amphiphilic block copolymer of Example 1, the Tg value of the polymer increased from -35 °C (Cy1) to -28 °C (Cy3) as the degree of polymerization of CHGE increased. In addition, it was confirmed that the Tg of the mPEG-b-PCHGE was similar to that of the TFGE block copolymer, but lower than that of the TPGE block copolymer. It can be seen that the Tg is increased due to the cyclohexyl group of CHGE, but the result is lower than the Tg of TPGE because CHGE has a more linear structure than TPGE.

Experimental Example 3: MALDI-ToF spectroscopy and hydrolysis reaction analysis

After confirming the synthesis of the PCHGE homopolymer of Comparative Example 1 through NMR and GPC in Experimental Examples 1 and 2, MALDI-ToF spectroscopy was performed to confirm whether CHGE was cross-linked to the PCHGE homopolymer. The results are shown in FIG. 2 .

2 shows the results of MALDI-ToF mass spectrum analysis from 2750 to 4500 Da for the mPEG-b-PCHGE block copolymer prepared in Example 1. FIG. In FIG. 2, each symbol corresponds to an intact polymer (red circle) and a partially decomposed polymer fragment (blue triangle and green square) during measurement. Referring to FIG. 2, the molecular weight of 3734.9 g/mol in the MALDI-ToF spectrum is a benzyl alcohol initiator (108.06 g mol-1), 18 monomers (200.14 g mol-1) and Na ⁺ as a counter ion. Corresponding to the polymer, two types of small peaks were observed due to partial decomposition of the cyclohexyloxy group during the measurement. In particular, the interval between the main signal and the minor signal corresponds to the molecular weight of the functional CHGE monomer, indicating that polymerization was successful.

Before examining the self-assembly behavior of the amphiphilic block copolymer prepared in Example 1, the hydrolysis kinetics of the CHGE monomer was investigated through quantum mechanical calculation using the density functional theory, and the results are shown in FIG. 3 . Here, the hydrolysis kinetics were compared with other types of monomers with acetal groups such as ethoxyethyl propylether (EEPE), tetrahydropyranyl propylether (TFPE) and tetrahydropyranyl propylether (TPPE).

Figure 3 schematically shows the energy diagram (a) of the hydrolysis reaction coordinates of various model acetal side chain compounds (CHPE, TPPE, TFPE, EEPE) and the proposed hydrolysis mechanism (b) of CHPE. The green molecule in FIG. 3 is a water molecule involved in the hydrolysis of CHPE. In addition, cyclohexyloxy propyl ether (CHPE) was synthesized as a new model compound in consideration of the side chain structure formed after polymerization of the CHGE monomer.

Referring to FIG. 3, in the first step, 25 explicit water molecules (25 H ₂ O) and additional protons were included to calculate the proton energy barrier. An optimized structure of the model compound with the lowest energy structure was obtained, including the transition state structures before and after protonation. In particular, protonation of the outer shell of the water molecule to CHPE revealed the large hydrophobicity of the model compound. The reaction energy barrier (ΔE) was then calculated with limited optimization according to the fixed distance between the oxygen and the proton in the CHPE structure. The reactive energy profile showed the protonation of the model acetal compound along the OH bond length. In addition, the CHPE (29.0 kcal/mol) has the highest energy barrier (ΔE) to protonation than all other monomers including the TPPE (24.2 kcal/mol), TFPE (11.2 kcal/mol) and EEPE (10.0 kcal/mol). ) was shown. This means that CHPE has the highest hydrophobicity than other acetal model compounds.

In addition, the hydrophobicity of each monomer was evaluated using the partition coefficient (logP) with the computational model ALOGPS 2.1. The calculated logP values were 2.93 (CHPE), 1.72 (TPPE) and 1.31 (TFPE) ²⁴ , supporting the observed trend in the reactive energy profile.

In general, the total hydrolysis of an acetal bond involves two steps: (1) protonation step and (2) bond cleavage step. The rate determining step of the overall hydrolysis was observed to be the protonation reaction with the highest value of 29.0 kcal/mol for CHPE. Hydrolysis of the protonated CHPE compound (i.e., H+-CHPE; Figure 4b) using two explicit water molecules for hydrolysis of the protonated CHPE compound through an activation energy barrier of about 1.0 kcal/mol. The reaction energy barrier and transition state were calculated in each step. This process was similarly observed for ring-opening of H + -TFPE and H + -TPPE as a single transition state with significantly lower energy barriers (0.37 kcal/mol and 0.83 kcal/mol, respectively) compared to the protonation step. In addition, no activation energy barrier was observed for C-O bond breakage for H+ -EEPE, suggesting that co-hydrolysis followed by protonation step.

Motivating computer analysis of the model compound, hydrolysis of the CHPE model compound was performed by in situ 1H NMR spectroscopy under acidic conditions of sodium acetate-d3/acetic acid-d4 buffer at pH 5.0. However, the solubility of CHPE monomer in aqueous buffer was limited, preventing hydrolysis monitoring unlike other model acetal compounds. Together with the calculation results, the hydrolysis of acetal groups in CHPE was prolonged due to the high hydrophobicity of the CHPE model compound.

Experimental Example 4: DLS and AFM evaluation

The size and shape of the Cy1, Cy2 and Cy3 micelles prepared in Example 1 were confirmed using dynamic light scattering (DLS) and atomic force microscopy (AFM). The results are shown in FIG. 4 .

4 is an intensity average hydrodynamic diameter (Dh) distribution diagram (a-c) of Cy1, Cy2, and Cy3 micelles prepared in Example 1 and AFM images (d-f) of Cy1, Cy2 and Cy3 micelles with corresponding line scan profiles. Referring to FIG. 4 (a-c), the concentration of all polymers performed in the DLS measurement was above the CMC value (1 mg/mL). In addition, the hydrodynamic diameters (Dh) of each micelle measured in DLS were 26.72 ± 1.99 (Cy1), 85.06 ± 0.54 (Cy2), and 118.56 ± 4.21 nm (Cy3), and the diameter increased with increasing number of CHGEs. Through this, it could be inferred that the size of micelles increased due to the presence of steric hindrance in the hydrophobic core of micelles due to the increase of bulky hydrophobic units (CHGEs).

Also, referring to (d-f) of FIG. 4, in the AFM image, Cy1 is DAFM = 55.16 ± 1.8 nm, Cy2 is DAFM = 91.27 ± 2.3 nm, and Cy3 is DAFM = 130.89 ± 1.4 nm. The micelles have a spherical shape and constant diameter, respectively. distribution was shown, and it was confirmed that the level was similar to that of the DLS result.

Experimental Example 5: Evaluation of encapsulation efficiency

The encapsulation efficiency of the micelles was evaluated for Cy1, Cy2, and Cy3 micelles prepared in Example 1 and E60, P37, and F47 of Comparative Examples 2 to 4, and the results are shown in FIG. 5 .

The encapsulation efficiency (EE) of micelles was measured as follows. A 0.1 mL solution of the model hydrophobic dye, Nile Red (50 μg/mL in acetone) was added to a solution of mPEG-b-PCHGE block copolymer (5 mg) in acetone (0.1 mL) and the mixture was stirred at room temperature for 30 min. . A total of 5 mL deionized water was added to the solution using a syringe pump at a rate of 0.5 mL/min. The solution was then allowed to equilibrate overnight, the lid was opened and the acetone evaporated. After filtration using a 0.45 μm syringe filter to remove unloaded Nile Red, the solution was freeze-dried and redissolved in 1.0 mL acetone. The amount of Nile Red encapsulated in micelles was measured using a fluorometer in a 1 x 1 cm quartz cell, and encapsulation efficiency (EE) was calculated by Equation 1 below.

[Formula 1]

5 is an encapsulation efficiency (a) of Nile Red in Cy1, Cy2 and Cy3 of Example 1 and E60, P37, and F47 of Comparative Examples 2 to 4 and actual images of the encapsulation efficiency of Cy1, Cy2 and Cy3 (b) ) are shown respectively. 5, Cy1, Cy2, and Cy3 of Example 1 had Nile Red load efficiencies of 20.35% (Cy1), 57.59% (Cy2) and 61.47% (Cy3) in each micelle core. This confirmed that the encapsulation efficiency in other existing studies ( Biomacromolecules 2014, 15, (11), 4281-4292.) showed a minimum of 26% and a maximum of 53.5%, which was lower than that of the CHGE-based micelles of Example 1. In addition, in comparison with the previous study, E60, P37, and F47 of Comparative Examples 2 to 4 using acetal-containing polymer were 10.9% (E60), 16.6% (P37) and 9.8% (F47). It was found that the effect was increased. In addition, the loading efficiency of micelles increased with the increase of the CHGE monomer unit, and was saturated in Cy2, which was in good agreement with the CMC value. Through this, it was confirmed that when a hydrophobic and bulky CHGE monomer was introduced into the polymer, micelles with excellent loading efficiency could be formed.

Experimental Example 6: Evaluation of decomposition rate in an acidic environment

Although polymeric micelles are promising as drug carriers, the stability of micelles is still challenging for biological applications. In particular, considering the various biological substances that can be encountered during circulation, the encapsulation of hydrophobic drugs is affected by various proteins in the blood. To this end, Cy1, Cy2, Cy3 prepared in Example 1 and E60, P37, and F47 of Comparative Examples 2 to 4 were applied to a drug release profile based on pyrene fluorescence method in various environments (FBS, PBS, pH 5.0 and pH 7.4) The degradation rate of micelles was evaluated. The results are shown in FIG. 6 .

6 is a schematic diagram (a) and chemical structure change (b) of a drug release profile based on the pyrene fluorescence method using Cy1, Cy2, Cy3 prepared in Example 1 and E60, P37, and F47 of Comparative Examples 2 to 4 Analysis of drug release kinetics (c, d) of micelles using Cy1, Cy2, Cy3 prepared in Example 1 and E60, P37, F47 of Comparative Examples 2 to 4 loaded with pyrene at pH 5.0 and pH 7.4 the results are shown. Referring to FIG. 6 (a, b), the amphiphilic block copolymer of Example 1 is present in the form of micelles, but swells as the acetal bond is protonated by water molecules in the solvent. When a ringing phenomenon occurs and hydrolysis is performed in the form of polyglycerol (PG), micelles are decomposed and the drug is released.

6 (c, d) is a result of monitoring the stability of each pyrene-containing micelles with respect to the change in intensity of the I339/I332 fluorescence ratio in acidic (pH 5.0) and normal (pH 7.4) environments at a temperature of 37°C. As a result of examining the degradation of micelles in the normal (pH 7.4) environment, the fluorescence ratio intensity of I339/I332 in the Cy1 to Cy3 micelles of Example 1 did not change, meaning that the micelles were stable in the pH 7.4 environment. On the other hand, in micelles in the acidic (pH 5.0) environment, the CHGE moiety was changed to hydrophilic linear PG by hydrolysis, and degradation was observed due to disruption of the hydrophobic/hydrophilic balance. As micelles responded to low pH, pyrene encapsulated in the core was released, Cy1 decreased most markedly, and Cy2 and Cy3 intensity also decreased over time. In addition, in the case of E60, P37, and F47 of Comparative Examples 2 to 4, it was confirmed that the pyrene strength with time rapidly disappeared due to the rapid decomposition of micelles in an acidic (pH 5.0) environment.

In particular, the release rate of pyrene was slower when including more units of CHGE monomer in micelles. For example, Cy1 was most rapidly degraded after 4 days to release most of pyrene, Cy2 was completely degraded after 12 days, and the longest was completely degraded after 14 days. These results are consistent with the CMC values of Cy1 to Cy3, indicating that the release kinetics can be controlled. In addition, in the case of Cy3, which has the largest hydrophobic site, it has the strongest hydrophobic interaction in the core, so it has the longest release time due to high-density packing, and it can be seen that long-term sustained release is possible.

Experimental Example 7: Evaluation of encapsulation stability in a biological environment (PBS and FBS)

For Cy1, Cy2, and Cy3 prepared in Example 1, the stability of micelles in various biological environments (PBS and FBS) was investigated. A fluorescence resonance energy transfer (FRET)-based method was used to confirm the stability of micelles in a biological environment. The stability of micelles was analyzed by loading FRET pairs of DiO (FRET-donor) and DiI (FRET-acceptor) into the hydrophobic core of micelles. Of note, when micelles are stable under harsh conditions, efficient energy transfer from DiO (FRET-donor) to DiI (FRET-acceptor) occurs because the FRET pair is located close to the core, resulting in strong emission near 560 nm. However, when micelles are unstable, they become FRET pairs. Only strong DiO emission (FRET donor) appears at 510 nm as the positions are free and no energy is transferred between the pairs. The analysis results are shown in FIG. 7 .

7 shows the results of FRET-based encapsulation stability analysis in PBS and FBS using fluorescence emission spectra (λex = 450 nm) for Cy1, Cy2, and Cy3 prepared in Example 1 above. 7, Cy1, Cy2 and Cy3 micelles showed strong emission only at about 550 nm in phosphate-buffer saline (PBS) for 192 hours, and no peak was observed at 510 nm. As described above, since DiO and DiI are close to the core of micelles, it can be seen that these results are from efficient energy transfer, which means that micelles have excellent stability in PBS.

Also, almost no peak change during the entire measurement time was observed in Cy3 micelles, but larger peak changes were observed after 120 hours in Cy2 and Cy1 micelles. Through this, it was found that as the number of hydrophobic units increased, DiO and DiI of the core were dense, and thus the stability of the micellar core was increased and peak fluctuations were not observed.

In addition, as a result of testing up to 72 hours due to the formation of aggregates of proteins and lipids present in fetal bovine serum (FBS), strong emission at 550 nm was observed in all micelles for 72 hours, and 510 nm No peak change was observed. As with the PBS data, the peak change was observed only in Cy1, not Cy2 and Cy3. These results indicated that all micelles were unaffected by the proteins in the serum and could safely keep the payload in the core. In addition, it was confirmed that overall micelles showed excellent stability in a biological environment and deteriorated in response to low pH.

Experimental Example 8: In vivo cytotoxicity evaluation

In order to evaluate the applicability of Cy1, Cy2, and Cy3 prepared in Example 1 in a drug delivery system, a cell viability test of micelles was performed. In particular, polymer micelles must have high biocompatibility for drug delivery applications. To measure the cell viability of micelles synthesized as a drug carrier, MTT assay for Hela cells was investigated.

8 shows the in vitro cell viability assay results determined by MTT assay using HeLa cells for Cy1, Cy2, and Cy3 prepared in Example 1 above. Referring to FIG. 8, in the case of Cy1, Cy2, and Cy3, it was confirmed that cell viability was maintained at about 100% even when micelles were treated with various concentrations or exposed to a concentration of 1000 μg/mL. These results indicate that each of the amphiphilic block copolymers of Cy1, Cy2, and Cy3 is suitable for application as a drug delivery carrier. That is, the Cy1, Cy2 and Cy3 showed excellent cell viability against Hela cells, indicating that they are suitable as drug carriers.

Claims (15)

A pH-sensitive amphiphilic block copolymer in which polycyclohexyloxyethyl glycidyl ether (PCHGE) having hydrophobicity at one end of a hydrophilic polymer is copolymerized by anionic ring-opening polymerization.
According to claim 1,
The hydrophilic polymer is poly(ethylene glycol) methyl ether, polyethylene glycol diacrylate, polyethylene glycol, polyethylene imide, polyamino acid, polymethyl methacrylate, polyethylene oxide, polyvinyl alcohol, polyacrylic acid and polyvinyl pyrrolidone. A pH-sensitive amphiphilic block copolymer that is at least one selected from the group consisting of.
According to claim 1,
The pH-sensitive amphiphilic block copolymer is a pH-sensitive amphiphilic that is a poly (ethylene glycol) methyl ether-block-polycyclohexyloxyethyl glycidyl ether (PEG-b-PCHGE) represented by the following Chemical Formula 1 block copolymer.
[Formula 1]

(In Formula 1, R ₁ is hydrogen, an alkyl group having 1 to 4 carbon atoms, a cycle group (

) or a phenyl group (

), wherein R ₂ is CH ₃ , CH ₂ CH ₃ or -NH ₂ , n and m are the number of repeats of each repeating unit, n is an integer of 50 to 200, m is an integer of 3 to 46, n:m is 1: 0.01 to 1: 0.9.)
According to claim 1,
The pH-sensitive amphiphilic block copolymer has a number average molecular weight (Mn, _NMR ) of 6,000 to 20,000 g/mol, a molecular weight dispersion (Mw/Mn) of 1.08 to 1.19, and a glass transition temperature (Tg) of -40 to -25 °C of the pH-sensitive amphiphilic block copolymer.
According to claim 1,
The pH-sensitive amphiphilic block copolymer is a pH-sensitive amphiphilic block copolymer having a critical micelle concentration (CMC) of 1.4 to 13 mg/L.
According to claim 1,
The pH-sensitive amphiphilic block copolymer forms self-assembled micelles when the pH is in the range of 7.2 to 7.6, and the micelles are disintegrated when the pH is in the range of 1 to 5. .
A pH-sensitive amphiphilic block copolymer according to any one of claims 1 to 6; and
Polymeric micelles comprising a molecular imaging marker, contrast agent or therapeutic agent bound to polycyclohexyloxyethyl glycidyl ether (PCHGE) of the pH-sensitive amphiphilic block copolymer.
8. The method of claim 7,
The molecular imaging marker is pyrene, pyrenebutyric acid, pyrene methylamine, aminopyrene (1-Aminopyrene), pyrenboronic acid (Pyrene-1-boronic acid), iron oxide and oxidation One or more polymer micelles selected from the group consisting of manganese.
8. The method of claim 7,
The therapeutic agent is a polymeric micellar of at least one selected from the group consisting of peptides, proteins, anticancer agents, anti-inflammatory drugs, antibiotics, antibacterial agents, hormones, genes and vaccines.
8. The method of claim 7,
The polymer micelles are polymer micelles having an average diameter of 20 to 200 nm.
According to claim 7,
The polymeric micelles are formulated for injection, transdermal or oral use so that the polymeric micelles can be administered via oral, transdermal, ocular, subcutaneous, intravenous, intramuscular or intraperitoneal routes.
A pH-sensitive target delivery system comprising the polymeric micelles according to claim 7.
synthesizing cyclohexyloxyethyl glycidyl ether (CHGE); and
A hydrophilic polymer, the cyclohexyloxyethyl glycidyl ether (CHGE) and a catalyst are added to an organic solvent, and anionic ring-opening polymerization to prepare a pH-sensitive amphiphilic block copolymer; pH-sensitive amphiphilic block comprising A method for preparing a copolymer.
14. The method of claim 13,
In the step of preparing the pH-sensitive amphiphilic block copolymer, the hydrophilic polymer and cyclohexyloxyethyl glycidyl ether (CHGE) are mixed in a molar ratio of 1: 5 to 60 of the pH-sensitive amphiphilic block copolymer. manufacturing method.
14. The method of claim 13,
The step of preparing the pH-sensitive amphiphilic block copolymer is a method of producing a pH-sensitive amphiphilic block copolymer by polymerization at 50 to 100 ℃ for 10 to 30 hours.

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