Polycaprolactone-based amphiphilic copolymer as well as preparation method and application thereof

Abstract

The invention discloses a polycaprolactone-based amphiphilic copolymer, which is prepared from mPEG 90, 4-phenyl caprolactone and caprolactone in a molar ratio of 1: (5-50): (2-60) through TBD catalysis. Or, mPEG90 and 4-phenyl caprolactone in a molar ratio of 1: (5-50) are catalyzed by TBD (tetrabutyl disulfide) to prepare the TBD. The polycaprolactone-based amphiphilic copolymer provided by the invention is an amphiphilic polymer, and can be self-assembled into micelles in water for entrapment of an anti-cancer drug adriamycin; compared with mPEG-PCL with the same molecular weight, the polycaprolactone-based amphiphilic copolymer has higher drug loading capacity and stability.

Description

Technical Field

[0001] The present invention belongs to the fields of materials science and biomedical materials. Specifically, it relates to a polycaprolactone-based amphiphilic copolymer, its preparation method and application. Background Art

[0002] As a disease that seriously threatens human health, chemotherapy is an important treatment method. However, traditional chemotherapy drugs lack tumor specificity and will damage normal cells when killing cancer cells, bringing serious side effects, which greatly limits the treatment effect and the quality of life of patients. An ideal drug delivery system (DDS) should be able to efficiently and specifically deliver drugs to tumor tissues and reduce the impact on normal tissues. However, existing drug carriers have many limitations. Common drug carriers such as liposomes and ordinary polymer micelles have limited drug loading capacity. For example, the drug loading capacity of traditional liposomes for doxorubicin is only 5-10% (w / w), and they lack responsiveness to the tumor microenvironment. The concentration of glutathione (GSH) in tumor cells is 4-10 times higher than that in normal cells, and the pH value is acidic, but conventional carriers cannot utilize these differences to accurately release drugs.

[0003] Polycaprolactone has been widely used in the field of drug carriers due to its good biocompatibility, biodegradability and low toxicity. However, ordinary amphiphilic polymers such as mPEG-PCL have low encapsulation efficiency for hydrophobic drugs and lack environmental responsiveness. Chemical modification of the hydrophobic segment of PCL has become a research hotspot. For example, introducing an aromatic group benzene can increase the stacking and other interactions with hydrophobic drugs, greatly improving the drug loading capacity. For drugs such as doxorubicin and paclitaxel, the drug loading capacity can be increased by 2-3 times compared with ordinary mPEG-PCL. Summary of the Invention

[0004] In order to overcome the disadvantages of low drug loading capacity and poor stability of mPEG-PCL drug-loaded micelles, the purpose of the present invention is to provide a polycaprolactone-based amphiphilic copolymer, which can effectively improve the drug loading capacity and the stability of micelles.

[0005] The second purpose of the present invention is to provide a preparation method of the polycaprolactone-based amphiphilic copolymer.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present invention is as follows:

[0007] In the first aspect of the present invention, there is provided a polycaprolactone-based amphiphilic copolymer, which is prepared by TBD catalysis from mPEG 90 , 4-phenylcaprolactone and caprolactone with a molar ratio of 1:5 to 50:2 to 60;

[0008] Or, it is prepared by TBD catalysis from mPEG 90 , 4-phenylcaprolactone with a molar ratio of 1:5 to 50.

[0009] The structural general formula of the polycaprolactone-based amphiphilic copolymer is as follows:

[0010]

[0011] x = 10 - 50 (preferably 11, 21, 30, 39, 48), y = 0 - 40 (preferably 0, 7, 18, 27, 35).

[0012] The polycaprolactone-based amphiphilic copolymer is selected from one of the following structures:

[0013] x = 11, y = 35;

[0014] x = 21, y = 27;

[0015] x = 30, y = 18;

[0016] x = 39, y = 7;

[0017] x = 48.

[0018] In the second aspect of the present invention, a preparation method of the polycaprolactone-based amphiphilic copolymer is provided, including the following steps:

[0019] Under argon protection, mPEG with a molar ratio of 1:(5 - 50):(2 - 60) (preferably 1:10:40, 1:20:30, 1:30:20, 1:40:10) 90 , 4-phenylcaprolactone (abbreviated as PhCL) and caprolactone (CL) are mixed, heated and evacuated (stirred and evacuated for 3 h at a temperature of 60 °C), TBD (1,5,7-triazabicyclo[4.4.0]dodec-5-ene), dichloromethane are added, and TBD accounts for 1 - 7% (preferably 5%) of the total mass of 4-phenylcaprolactone and caprolactone, and the reaction is sealed at room temperature (for 1 - 3 h, preferably 2.5 h) to obtain the polycaprolactone-based amphiphilic copolymer;

[0020] Or,

[0021] Under argon protection, mPEG with a molar ratio of 1:(5 - 50) (preferably 1:50) 90, mixed with 4-phenylcaprolactone (abbreviated as PhCL), heated and evacuated (stirred and evacuated for 3 h at a temperature of 60 °C), TBD and dichloromethane were added, and TBD accounted for 1-7% (preferably 5%) of the mass of 4-phenylcaprolactone, and the reaction was sealed at room temperature (for 1-3 h, preferably 2.5 h) to obtain the polycaprolactone-based amphiphilic copolymer.

[0022] The mPEG 90 is methoxypolyethylene glycol with a weight-average molecular weight of 4000.

[0023] The preparation method of the 4-phenylcaprolactone (abbreviated as PhCL) includes the following steps:

[0024]

[0025] 4-Phenylcyclohexanone and m-chloroperbenzoic acid with a molar ratio of 1:(1.1-1.3) (preferably 1:1.2) were dissolved in dichloromethane, and the reaction was carried out in an ice-water bath for at least 24 hours to obtain the 4-phenylcaprolactone (abbreviated as PhCL).

[0026] In the third aspect of the present invention, a drug-loaded micelle is provided, which is prepared from the polycaprolactone-based amphiphilic copolymer and an anticancer drug.

[0027] The anticancer drug is selected from doxorubicin hydrochloride.

[0028] The mass ratio of the anticancer drug to the polycaprolactone-based amphiphilic copolymer is 1:1-10 (preferably 1:5).

[0029] In the fourth aspect of the present invention, a preparation method of the drug-loaded micelle is provided, including the following steps:

[0030] The polycaprolactone-based amphiphilic copolymer was mixed with the anticancer drug solution after dehydrochlorination, and dropped into stirred deionized water. After the micelle structure was stable, dialysis was carried out for at least 24 h, and deionized water was added to obtain the drug-loaded micelle solution.

[0031] The dialysis conditions: M W CO 3.5 kDa.

[0032] The preparation of the anticancer drug solution:

[0033] The anticancer drug was dissolved in DMSO, catalytic amount of triethylamine was added, and the reaction was carried out in the dark at room temperature (for 1-5 h, preferably 4 h) to obtain the anticancer drug solution.

[0034] In the fifth aspect of the present invention, an application of the drug-loaded micelle in the preparation of anticancer drugs is provided.

[0035] The cancer mentioned refers to breast cancer, and the cancer cells are MCF-7 cells.

[0036] Due to the adoption of the above technical solution, the present invention has the following advantages and beneficial effects:

[0037] The polycaprolactone-based amphiphilic copolymer provided by the present invention is an amphiphilic polymer, which can self-assemble into micelles in water for encapsulating the anticancer drug doxorubicin; compared with mPEG-PCL with the same molecular weight, the polycaprolactone-based amphiphilic copolymer has a higher drug loading and stability.

[0038] The experimental results of the present invention show that, compared with mPEG-PCL, due to the stacking interaction between the polycaprolactone-based amphiphilic copolymer and the drug, it has a higher drug loading and stability, but the introduction of phenyl groups will increase the rigidity of the hydrophobic segment, resulting in a decrease in its drug encapsulation ability. Finally, it is obtained that when x = 21 and y = 27, the polymer has the best drug encapsulation ability.

[0039] In summary, the present invention introduces phenyl groups into polycaprolactone to prepare a polycaprolactone-based amphiphilic copolymer, which is beneficial to improving the drug loading, encapsulation efficiency and stability of micelles. Description of the Drawings

[0040] Figure 1 is the 1 1H NMR spectrum of 4-phenylcaprolactone.

[0041] Figure 2 is the GPC curve of the polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL x -co-CL y ).

[0042] Figure 3 is the x 1H NMR spectrum of the polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL y -co-CL 1 ).

[0043] Figure 4 is the x 1H NMR spectrum of the polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL 1 ).

[0044] Figure 5 is the 1 1H NMR spectrum of the polycaprolactone-based amphiphilic copolymer mPEG-b-PCL.

[0045] Figure 6 is the DLS curve of the drug-loaded micelles of the polycaprolactone-based amphiphilic copolymer.

[0046] Figure 7 It is the TEM image of the drug-loaded micelles of polycaprolactone-based amphiphilic copolymers.

[0047] Figure 8 It is a schematic diagram of the drug loading amount and encapsulation efficiency of the drug-loaded micelles of polycaprolactone-based amphiphilic copolymers.

[0048] Figure 9 It is a line graph of the stability of the drug-loaded micelles in each group within 30 days. Detailed implementation manners

[0049] To illustrate the present invention more clearly, the present invention will be further described below in conjunction with preferred embodiments. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the protection scope of the present invention.

[0050] Example 1

[0051] Preparation of 4-phenylcaprolactone (abbreviated as PhCL):

[0052]

[0053] To a round-bottom flask containing 200 ml of DCM, 4-phenylcyclohexanone (8.71 g, 50 mmol) and meta-chloroperoxybenzoic acid (m-CPBA) (10.35 g, 60 mmol) were successively added, and the reaction was stirred in an ice-water bath for 24 h. After the reaction was completed, the reaction solution was filtered to remove the insoluble white solid, and the obtained organic phase was washed successively with saturated Na2S2O3, NaHCO3, and NaCl solutions 3 times. The organic phase was concentrated by rotary evaporation to obtain a crude white crystal product, and the crude product was recrystallized at least 3 times with an ethyl acetate / petroleum ether double-solvent system, and finally pure white needle-like crystals of PhCL were obtained. Figure 1 It is the 1 1H NMR spectrum of 4-phenylcaprolactone. 1 1H NMR (400 MHz, Chloroform-d) δ (ppm): 7.16 - 7.35 (-CH(C6H5)-), 4.25, 4.42 (-COOCH2CH2-), 3.35 (H2O), 2.29 (-CH2COOCH2-), 2.54 (-CH2CH(C6H5)CH2-), 2.50 (DMSO), 1.99 (-OCOCH2CH2-), 1.88 (-OCOCH2CH2-, -COOCH2CH2-), 1.67 (-COOCH2CH2-).

[0054] Polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL x -co-CLy ) Preparation (b represents block, P represents the polymerization of the following two monomers):

[0055]

[0056] x = 11, y = 35.

[0057] First, the eggplant-shaped polymerization flask was baked three times with a spray gun under vacuum conditions to remove trace amounts of water vapor. Then, under argon conditions, methoxypolyethylene glycol (abbreviated as mPEG 90 ) (0.4 g, 0.1 mmol), PhCL (0.191 g, 1 mmol), and ε-caprolactone (CL) (0.456 g, 4 mmol) were added. The mixture was stirred and evacuated for 3 h in an oil bath at 60 °C to remove trace solvents and moisture. Then, 0.0323 g of 1,5,7-triazabicyclo[4.4.0]dodec-5-ene (abbreviated as TBD) and 2.5 ml of DCM were added. TBD accounted for 5% of the total mass of 4-phenylcaprolactone and caprolactone. Under argon protection, the reaction was stirred and sealed at room temperature for 2.5 h. After the reaction, 50 μL of acetic acid was added to the polymerization system, and the reaction was stirred for 10 min to quench the catalyst. Then, the polymerization solution was dropped into a large amount of ice-cold diethyl ether, and the supernatant was removed by centrifugation. The precipitation was repeated three times, and the precipitate was collected and dried under vacuum to constant weight to obtain the polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL x -co-CL y ). Figure 2 is the GPC curve of the polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL x -co-CL y ). Figure 2 It can be seen from that all the curves are single peaks, indicating that the polymer was successfully synthesized. Figure 3 is the x HNMR spectrum of the polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL y -co-CL ). 1 HNMR spectrum. 11H NMR (400 MHz, Chloroform-d) δ (ppm): 7.06 - 7.32 (-CH(C6H5)-), 3.95, 3.90 (-CH2CH(C6H5)CH2CH2O-), 3.75, 3.68 (-COCH2CH2CH2CH2CH2O-), 3.51 (CH3OCH2CH2O-), 3.34 (H2O), 3.24 (CH3OCH2CH2O-), 2.57 (-CH2CH(C6H5)-), 2.50 (DMSO), 2.24, 2.18 (-COCH2CH2CH(C6H5)CH2CH2O-), 2.0 (-COCH2CH2CH2CH2CH2O-), 1.85 (-COCH2CH2CH(C6H5)CH2CH2O-), 1.71 (-COCH2CH2CH(C6H5)CH2CH2O-), 1.47 (-COCH2CH2CH2CH2CH2O-), 1.23 (-COCH2CH2CH2CH2CH2O-).

[0058] Example 2

[0059] Preparation of polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL x -co-CL y ):

[0060]

[0061] x = 21, y = 27.

[0062] First, the eggplant-shaped polymerization flask was baked three times with a spray gun under vacuum to remove trace water vapor. Then, under argon, mPEG 90 (0.4 g, 0.1 mmol), PhCL (0.382 g, 2 mmol), and CL (0.342 g, 3 mmol) were added. The mixture was stirred and evacuated under a 60 °C oil bath for 3 h to remove trace solvents and moisture. Then, 0.0362 g of TBD and 2.5 ml of DCM were added. TBD accounted for 5% of the total mass of 4-phenylcaprolactone and caprolactone. Under argon protection, the reaction was stirred and sealed at room temperature for 2.5 h. After the reaction, 50 μL of acetic acid was added to the polymerization system, and the reaction was stirred for 10 min to quench the catalyst. Then, the polymerization solution was dropped into a large amount of ice ether, and the supernatant was removed by centrifugation. The precipitation was repeated three times, and the precipitate was collected and dried under vacuum to constant weight to obtain the polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL x -co-CL y ). 11H NMR (400 MHz, Chloroform-d) δ (ppm): 7.06 - 7.32 (-CH(C6H5)-), 3.95, 3.90 (-CH2CH(C6H5)CH2CH2O-),

[0063] 3.75, 3.68 (-COCH2CH2CH2CH2CH2O-), 3.51 (CH3OCH2CH2O-), 3.34 (H2O), 3.24 (CH3OCH2CH2O-), 2.57 (-CH2CH(C6H5)-), 2.50 (DMSO), 2.24, 2.18 (-COCH2CH2CH(C6H5)CH2CH2O-), 2.0 (-COCH2CH2CH2CH2CH2O-), 1.85 (-COCH2CH2CH(C6H5)CH2CH2O-), 1.71 (-COCH2CH2CH(C6H5)CH2CH2O-), 1.47 (-COCH2CH2CH2CH2CH2O-), 1.23 (-COCH2CH2CH2CH2CH2O-).

[0064] Example 3

[0065] Polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL x -co-CL y ) Preparation

[0066]

[0067] x = 30, y = 18.

[0068] First, the eggplant-shaped polymerization flask was baked three times with a spray gun under vacuum conditions to remove trace water vapor. Then, under argon conditions, mPEG 90 (0.4 g, 0.1 mmol), PhCL (0.573 g, 3 mmol), CL (0.228 g, 2 mmol) were added, and the mixture was stirred and evacuated for 3 h in an oil bath at 60 °C to remove trace solvents and moisture. Then, 0.0399 g of TBD and 2.5 ml of DCM were added. TBD accounted for 5% of the total mass of 4-phenylcaprolactone and caprolactone. Under argon protection, the reaction was stirred and sealed at room temperature for 2.5 h. After the reaction, 50 μL of acetic acid was added to the polymerization system, and the reaction was stirred for 10 min to quench the catalyst. Then, the polymerization solution was dropped into a large amount of ice ether, and the supernatant was removed by centrifugation. The precipitation was repeated three times, and the precipitate was collected and dried under vacuum to constant weight to obtain the polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL x -co-CL y ).1 1H NMR (400 MHz, Chloroform-d) δ (ppm): 7.06 - 7.32 (-CH(C6H5)-), 3.95, 3.90 (-CH2CH(C6H5)CH2CH2O-),

[0069] 3.75, 3.68 (-COCH2CH2CH2CH2CH2O-), 3.51 (CH3OCH2CH2O-), 3.34 (H2O), 3.24 (CH3OCH2CH2O-), 2.57 (-CH2CH(C6H5)-), 2.50 (DMSO), 2.24, 2.18 (-COCH2CH2CH(C6H5)CH2CH2O-), 2.0 (-COCH2CH2CH2CH2CH2O-), 1.85 (-COCH2CH2CH(C6H5)CH2CH2O-), 1.71 (-COCH2CH2CH(C6H5)CH2CH2O-), 1.47 (-COCH2CH2CH2CH2CH2O-), 1.23 (-COCH2CH2CH2CH2CH2O).

[0070] Example 4

[0071] Polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL x -co-CL y ) Preparation

[0072]

[0073] x = 39, y = 7.

[0074] First, the eggplant-shaped polymerization flask was baked three times with a spray gun under vacuum to remove trace water vapor. Then, under argon, mPEG 90 (0.4 g, 0.1 mmol), PhCL (0.764 g, 4 mmol), and CL (0.114 g, 1 mmol) were added. The mixture was stirred and evacuated under a 60 °C oil bath for 3 h to remove trace solvents and moisture. Then, 0.0439 g of TBD and 2.5 ml of DCM were added. TBD accounted for 5% of the total mass of 4-phenylcaprolactone and caprolactone. Under argon protection, the reaction was stirred and sealed at room temperature for 2.5 h. After the reaction, 50 μL of acetic acid was added to the polymerization system, and the reaction was stirred for 10 min to quench the catalyst. Then, the polymerization solution was dropped into a large amount of ice-cold diethyl ether, and the supernatant was removed by centrifugation. The precipitation was repeated three times, and the precipitate was collected and dried under vacuum to constant weight to obtain the polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL x -co-CL y)。 1 1H NMR (400 MHz, Chloroform-d) δ (ppm): 7.06 - 7.32 (-CH(C6H5)-), 3.95, 3.90 (-CH2CH(C6H5)CH2CH2O-),

[0075] 3.75, 3.68 (-COCH2CH2CH2CH2CH2O-), 3.51 (CH3OCH2CH2O-), 3.34 (H2O), 3.24 (CH3OCH2CH2O-), 2.57 (-CH2CH(C6H5)-), 2.50 (DMSO), 2.24, 2.18 (-COCH2CH2CH(C6H5)CH2CH2O-), 2.0 (-COCH2CH2CH2CH2CH2O-), 1.85 (-COCH2CH2CH(C6H5)CH2CH2O-), 1.71 (-COCH2CH2CH(C6H5)CH2CH2O-), 1.47 (-COCH2CH2CH2CH2CH2O-), 1.23 (-COCH2CH2CH2CH2CH2O-).

[0076] Example 5

[0077] Polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL x ) Preparation

[0078]

[0079] x = 48.

[0080] First, the eggplant-shaped polymerization flask was baked three times with a spray gun under vacuum conditions to remove trace water vapor. Then, under argon conditions, mPEG 90 (0.4 g, 0.1 mmol), PhCL (0.955 g, 5 mmol) were added, and the mixture was stirred and evacuated for 3 h in an oil bath at 60 °C to remove trace solvents and moisture. Then 0.0477 g of TBD and 2.5 ml of DCM were added. TBD accounted for 5% of the total mass of 4-phenylcaprolactone. Under argon protection, the reaction was stirred and sealed at room temperature for 2.5 h. After the reaction, 50 μL of acetic acid was added to the polymerization system, and the reaction was stirred for 10 min to quench the catalyst. Then the polymerization solution was dropped into a large amount of ice ether, the supernatant was removed after centrifugation, and the precipitation was repeated three times. The precipitate was collected and dried under vacuum to constant weight to obtain the polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL x ) Figure 4 is the polycaprolactone-based amphiphilic copolymer mPEG-b-P(PhCL x )1 1H NMR spectrum 1 1H NMR (400 MHz, Chloroform-d) δ (ppm): 7.05 - 7.31 (-CH(C6H5)-), 3.67, 3.75 (-CH2CH(C6H5)CH2CH2O-), 3.5 (CH3OCH2CH2O-), 3.35 (H2O), 3.24 (CH3OCH2CH2O-), 2.54 (-CH(C6H5)-), 2.5 (DMSO), 1.94 (-COCH2CH2CH(C6H5)-), 1.81 (-COCH2CH2CH(C6H5)-), 1.69 (-CH (C6H5)CH2CH2O-).

[0081] Example 6

[0082] Preparation of polycaprolactone-based amphiphilic copolymer mPEG-b-PCLx

[0083]

[0084] x = 46

[0085] First, the eggplant-shaped polymerization flask was baked three times with a spray gun under vacuum conditions to remove trace water vapor. Then, under argon conditions, mPEG 90 (0.4 g, 0.1 mmol) and CL (0.57 g, 5 mmol) were added, and the mixture was stirred and evacuated for 3 h in an oil bath at 60 °C to remove trace solvents and moisture. Then, 0.0285 g of TBD and 2.5 ml of DCM were added. TBD accounted for 5% of the mass of caprolactone. Under argon protection, the reaction was stirred and sealed at room temperature for 2.5 h. After the reaction was completed, 50 μL of acetic acid was added to the polymerization system, and the reaction was stirred for 10 min to quench the catalyst. Then, the polymerization solution was dropped into a large amount of ice ether, and the supernatant was removed by centrifugation. The precipitation was repeated three times, and the precipitate was collected and dried under vacuum to constant weight to obtain the polycaprolactone-based amphiphilic copolymer mPEG-b-PCL 46 . Figure 5 is the 1 1H NMR spectrum of the polycaprolactone-based amphiphilic copolymer mPEG-b-PCL 11H NMR (400 MHz, CDCl3) δ (ppm): 7.26 (CDCl3), 4.05 (-COCH2CH2CH2CH2CH2O-), 3.62 (CH3OCH2CH2O-), 3.38 (CH3O-), 2.30 (-COCH2CH2CH2CH2CH2O-), 1.64 (-COCH2CH2CH2CH2CH2O-), 1.37 (-COCH2CH2CH2CH2CH2O).

[0086] Example 7

[0087] Preparation of Polycaprolactone-based Amphiphilic Copolymer Drug-loaded Micelles

[0088] Dissolve 10 mg of doxorubicin hydrochloride (DOX·HCl) in 1 ml of DMSO, add two drops of triethylamine to it, and react at room temperature in the dark for 4 h to remove hydrochloric acid. After the reaction, place it in the refrigerator for later use.

[0089] Accurately weigh 10 mg of the polycaprolactone-based amphiphilic copolymer prepared in Examples 1 to 6, mix it with 0.2 mL of the dehydrochlorinated doxorubicin solution with a concentration of 10 mg / mL. The mass ratio of doxorubicin to the polycaprolactone-based amphiphilic copolymer is 1:5. After the polycaprolactone-based amphiphilic copolymer is completely dissolved, slowly drop the mixed solution into 5 mL of stirred deionized water. After dropping, continue to stir for 2 h. After the micelle structure is stable, add all of it into a dialysis bag (M W CO 3.5 kDa), and dialyze in deionized water for 24 h to remove the solvent and unencapsulated small molecule substances. After dialysis, dilute the micelles to 10 mL with deionized water to obtain a polycaprolactone-based amphiphilic copolymer drug-loaded micelle solution with a concentration of 1 mg / mL. Figure 6 is the DLS curve of the polycaprolactone-based amphiphilic copolymer drug-loaded micelles. It can be seen from the figure that the particle size of the drug-loaded micelles is between 80 - 150 nm, and the polymer dispersity index PDI is less than 0.2. Figure 7 is the TEM image of the polycaprolactone-based amphiphilic copolymer drug-loaded micelles. It can be seen from the figure that the shapes of all micelles are spherical.

[0090] Calculation of Drug Loading and Encapsulation Efficiency of Polycaprolactone-based Amphiphilic Copolymer Drug-loaded Micelles

[0091] 1 mL of the drug-loaded micelles solution of polycaprolactone-based amphiphilic copolymer with a concentration of 1 mg / mL was freeze-dried. The obtained solid drug-loaded micelles were dissolved in 3 mL of DMF, and the absorbance of the solution at 506 nm was measured by UV-vis spectrum. Then, the content of DOX in the polymer drug-loaded micelles was calculated using the standard curve of DOX in DMF. The encapsulation efficiency (EE%) and drug loading content (DLC%) of the polymer drug-loaded micelles were calculated according to the following formula:

[0092]

[0093]

[0094] Figure 8 It is a schematic diagram of the drug loading content and encapsulation efficiency results of polycaprolactone-based amphiphilic copolymer drug-loaded micelles. Among them, P0 represents mPEG-b-PCL 46 drug-loaded micelles, P1 represents mPEG-b-P(PhCL 11 -co-CL 35 ) drug-loaded micelles, P2 represents mPEG-b-P(PhCL 21 -co-CL 27 ) drug-loaded micelles, P3 represents mPEG-b-P(PhCL 30 -co-CL 18 ) drug-loaded micelles, P4 represents mPEG-b-P(PhCL 39 -co-CL7) drug-loaded micelles, P5 represents mPEG-b-P(PhCL 48 ) drug-loaded micelles.

[0095] The encapsulation efficiency of P0 is 36.46 ± 4.59%, and the drug loading content is 7.92 ± 0.29%. The encapsulation efficiency of P1 is 63.28 ± 1.82%, and the drug loading content is 12.66 ± 0.36%. The encapsulation efficiency of P2 is 68.87 ± 0.53%, and the drug loading content is 13.77 ± 0.11%. The encapsulation efficiency of P3 is 58.73 ± 3.27%, and the drug loading content is 11.75 ± 0.65%. The encapsulation efficiency of P4 is 65.61 ± 2.34%, and the drug loading content is 13.12 ± 0.47%. The encapsulation efficiency of P5 is 61.92 ± 1.48%, and the drug loading content is 12.38 ± 0.30%.

[0096] It can be seen from Figure 8 that under the same feeding ratio, the drug loading content and encapsulation efficiency of P1 - P5 are higher than those of P0, indicating that phenylation improves the drug-loading ability of polycaprolactone. When x = 21, the encapsulation efficiency and drug loading content of mPEG-b-P(PhCL x -co-CL y ) drug-loaded micelles are the highest.

[0097] Through analysis, it can be seen that as the benzene ring content increases (i.e., the x value in the polymer increases), on the one hand, the stacking and other interactions between the polymer and the drug are enhanced, which is beneficial to improving the drug-loading capacity of the micelles. On the other hand, as the benzene ring content increases, the rigidity of the hydrophobic segment increases, resulting in a decrease in the mobility of the polymer chain segments and a decrease in its drug encapsulation capacity.

[0098] Example 8

[0099] Take 1 ml of each drug-loaded micelle prepared in Example 7 and place it in a quartz dish with light-transmitting on all four sides. Measure the particle size of each drug-loaded micelle using DLS every two days for 30 days. Analyze the stability of the drug-loaded micelles by comparing the particle size changes each time. Figure 9 It is a line graph showing the stability of each group of drug-loaded micelles within 30 days. As can be seen from the figure, the stability of the drug-loaded micelles of the phenyl-modified polycaprolactone-based amphiphilic copolymer is better than that of the mPEG-b-PCL without phenyl modification 46 This shows that the introduction of phenyl can improve the stability of the drug-loaded micelles.

[0100] The above are only the preferred embodiments of the present invention, and there is no any form of limitation to the present invention. Although the present invention has been disclosed as above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art of this patent, without departing from the scope of the technical solution of the present invention, can make some changes or modifications to the above-mentioned technical content by using the disclosed technical content to make equivalent embodiments with equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the present invention.

Claims

1. A polycaprolactone-based amphiphilic copolymer, characterized in that, It is prepared by catalytic reaction of mPEG, 4-phenylcaprolactone and caprolactone with a molar ratio of 1:5 to 50:2 to 60 by TBD; 90 ​ Or, it is prepared by catalyzing mPEG with a molar ratio of 1:5 to 50 90 and 4-phenylcaprolactone with TBD.

2. The polycaprolactone-based amphiphilic copolymer according to claim 1, characterized in that, The structural general formula is as follows: x = 10 - 50, y = 0 - 40.

3. A method for preparing the polycaprolactone-based amphiphilic copolymer according to claim 1 or 2, characterized in that, It includes the following steps: Under argon protection, mPEG with a molar ratio of 1:5 to 50:2 to 60 90 , 4-phenylcaprolactone and caprolactone were mixed, heated and evacuated, then TBD and dichloromethane were added. TBD accounted for 1 to 7% of the total mass of 4-phenylcaprolactone and caprolactone, and the reaction was sealed at room temperature to obtain the polycaprolactone-based amphiphilic copolymer; Or, Under argon protection, mPEG with a molar ratio of 1:5 to 50 90 , and 4-phenylcaprolactone are mixed, heated and evacuated, then TBD and dichloromethane are added. TBD accounts for 1 to 7% of the mass of 4-phenylcaprolactone, and the reaction is sealed at room temperature to obtain the polycaprolactone-based amphiphilic copolymer.

4. The preparation method of the polycaprolactone-based amphiphilic copolymer according to claim 3, characterized in that, The preparation method of the 4-phenylcaprolactone includes the following steps: Dissolve 4-phenylcyclohexanone and m-chloroperbenzoic acid with a molar ratio of 1:1.1 - 1.3 in dichloromethane, and react in an ice-water bath for at least 24 hours to obtain the 4-phenylcaprolactone.

5. A drug-loaded micelle, characterized in that, It is prepared from the polycaprolactone-based amphiphilic copolymer described in Claim 1 or 2 and an anticancer drug.

6. The drug-loaded micelle according to claim 5, characterized in that, The anticancer drug is selected from doxorubicin hydrochloride.

7. The drug-loaded micelle according to claim 5, wherein The mass ratio of the anticancer drug to the polycaprolactone-based amphiphilic copolymer is 1:1 - 10.

8. A method for preparing the drug-loaded micelles according to any one of claims 5 to 7, characterized in that, It includes the following steps: Mix the polycaprolactone-based amphiphilic copolymer with the anticancer drug solution after dehydrochlorination, drop it into stirred deionized water, dialyze for at least 24 h after the micelle structure is stable, and add deionized water to obtain the drug-loaded micelle solution.

9. The preparation method of the drug-loaded micelles according to claim 8, wherein, Preparation of the anticancer drug solution: Dissolve the anticancer drug in DMSO, add a catalytic amount of triethylamine, and react in the dark at room temperature to obtain the anticancer drug solution.

10. Use of the drug-loaded micelle according to any one of Claims 5 to 7 in the preparation of an anticancer drug.

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