A hydrogel microsphere and a preparation method and application thereof

Abstract

The application provides a hydrogel microsphere and a preparation method and application thereof, and belongs to the technical field of hydrogel microspheres.The hydrogel microsphere has a core-shell structure, comprises a shell formed by a polyethylene glycol derivative modified by an end acrylamide, and a core formed by an ionic monomer polymerization segment.The hydrogel microsphere has strong toughness and will not burst when swelling, can quickly adsorb a drug solution through swelling, realizes efficient, rapid and high-loading loading of the drug, has obvious sustained-release effect, and can effectively regulate drug release.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydrogel microspheres, and relates to a hydrogel microsphere and a preparation method and application thereof. BACKGROUND

[0002] Interventional therapy is to selectively introduce a microcatheter into a blood supply vessel of a tumor lesion site under the assistance of a medical imaging device, and then to perfuse an embolic agent to achieve the purpose of cutting off the blood supply of the tumor site, so that the tumor is "starved to death" due to insufficient nutrient supply. Therefore, the selection of the embolic agent is crucial for the interventional therapy of the tumor.

[0003] Drug-loaded hydrogel microspheres have excellent biocompatibility and drug loading and release performance, and are increasingly developing into an important class of biomedical materials. Existing microspheres can be divided into gelatin microspheres, starch microspheres, polylactic acid microspheres, chitosan microspheres, sodium alginate microspheres, polyvinyl alcohol microspheres, and ethyl cellulose microspheres according to the main material matrix, but the use of these microspheres in clinical treatment is limited due to various defects.

[0004] At present, the commonly used drug-loaded hydrogel microspheres for TACE (transcatheter arterial chemoembolization) surgery in China include Callispheres and DCBeads, which are all microspheres with polyvinyl alcohol (PVA) as the main material. Although the PVA type microspheres can meet the general application in clinical treatment, some problems have occurred in the use process, for example, the hydrophilicity and biocompatibility of the microspheres need to be further improved to avoid rejection in clinical treatment. In particular, the existing PVA type microspheres are in a wet spherical shape, need to be swollen in a specific buffer solution, and can only load cationic drugs through ion exchange and hydrogen bond interaction between the microspheres and the drug solution.

[0005] Polyethylene glycol is a synthetic polymer material with the best known biocompatibility, and has good water solubility. The polyethylene glycol microspheres prepared by the existing technology are mainly prepared by activating the alcohol hydroxyl group of polyethylene glycol into an ester bond, and then by polymerization reaction to form microspheres. The microspheres prepared by this method are easily hydrolyzed due to the ester bond connection, especially in the blood environment, causing the embolized blood vessels to be recanalized in a short period of time, and unable to achieve permanent embolization.

[0006] Therefore, in the field, the development of microspheres with better stability is the focus of research. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide a hydrogel microsphere and a preparation method and application thereof.

[0008] To achieve the purpose of the present application, the following technical solutions are adopted:

[0009] In one aspect, the present application provides a hydrogel microsphere having a core-shell structure, comprising a shell formed by end acrylamide modified polyethylene glycol derivative, and a core formed by ionic monomer polymer segment;

[0010] The end acrylamide modified polyethylene glycol derivative has the following structure of formula I:

[0011]

[0012] wherein R1 and R2 are independently selected from H, C1-C4 alkyl, -(CH2) q -OH; n is an integer from 1 to 12, R3 is selected from H or -CH3, m is 1 or 2, and q is 1 or 2.

[0013] The hydrogel microsphere of the present application has a super-hydrophilic core-shell structure, the outer layer is a relatively dense structure formed by polymerization of a large amount of polyethylene glycol monomer derivative, and the core layer is a relatively loose structure formed by polymerization of ionic monomer.

[0014] In the present application, the C1-C4 alkyl can be C1, C2, C3 or C4 alkyl, and specifically can be methyl, ethyl, n-propyl, isopropyl, n-butyl, etc.

[0015] Preferably, the preparation method of the end acrylamide modified polyethylene glycol derivative comprises the following steps:

[0016] The glycidyl ether compound of formula II reacts with the N-hydroxyalkyl acrylamide compound of formula III to obtain the polymer of formula I, and the reaction formula is as follows:

[0017]

[0018] Preferably, the glycidyl ether compound of formula II is selected from any one or a combination of at least two of ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, tetraethylene glycol diglycidyl ether, PEG200 diglycidyl ether or PEG500 diglycidyl ether; the structures of the listed glycidyl ether compounds are as follows:

[0019]

[0020] The general structure of PEG200 diglycidyl ether or PEG500 diglycidyl ether is as follows For PEG200 diglycidyl ether, n≈5, and for PEG500 diglycidyl ether, n≈12.

[0021] Preferably, the N-hydroxyalkyl acrylamide compound is selected from N-hydroxymethyl acrylamide, N-hydroxyethyl acrylamide, N-[tris(hydroxymethyl)methyl]acrylamide, N-(2-hydroxypropyl)acrylamide, N-(hydroxymethyl)methyl acrylamide, N-(hydroxyethyl)methyl acrylamide, N-[tris(hydroxymethyl)methyl]methyl acrylamide or N-(2-hydroxypropyl)methyl acrylamide, the structures of which are shown as follows, respectively:

[0022]

[0023] Preferably, the reaction is carried out in the presence of a basic substance.

[0024] Preferably, the basic substance is sodium hydroxide and / or potassium hydroxide. The basic substance is added to the reaction system in the form of an aqueous solution.

[0025] Preferably, the reaction is carried out at room temperature.

[0026] Preferably, the reaction time is 1-6h, for example 1h, 2h, 3h, 4h, 5h or 6h.

[0027] Preferably, the ionic monomer is selected from sodium acrylate, sodium methacrylate, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), sodium p-styrenesulfonate, sodium vinylsulfonate, (3-acrylamidopropyl)trimethylammonium chloride, (3-methacrylamidopropyl)trimethylammonium chloride, the structures of which are shown as follows:

[0028]

[0029] Preferably, the hydrogel microspheres have a particle size of 30-1400μm, for example 30μm, 50μm, 80μm, 100μm, 200μm, 500μm, 800μm, 1000μm, 1200μm or 1400μm.

[0030] The hydrogel microspheres of the present application, after being dried and reswollen, maintain the original morphology and particle size; the dry spheres are swelled to adsorb a drug solution, and loaded with drugs.

[0031] In another aspect, the present application provides a method for preparing the hydrogel microspheres as described above, which comprises polymerizing an end-group acrylamide-modified polyethylene glycol derivative with an ionic monomer to obtain the hydrogel microspheres.

[0032] In the present application, the water gel microspheres are obtained by polymerization of the polyethylene glycol derivative modified by end group acrylamide and ionic monomer, the microspheres have a super-hydrophilic core-shell structure, the outer layer is a relatively dense structure formed by polymerization of a large amount of polyethylene glycol derivative monomers, and the core layer is a relatively loose structure formed by polymerization of ionic monomers. The dense and highly hydrophilic polyethylene glycol derivative structure of the outer layer makes the microspheres have strong toughness and will not burst when swelling. After the microspheres are dehydrated and dried, dry balls are obtained, which can quickly swell in pure water or aqueous solution and maintain the original morphology and particle size of the wet balls.

[0033] Preferably, the amount of the ionic monomer is 1-8 times (for example, 1 times, 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, or 8 times) the molar amount of the polyethylene glycol derivative modified by end group acrylamide.

[0034] Preferably, the polymerization of the polyethylene glycol derivative modified by end group acrylamide and the ionic monomer is carried out under the initiation of a free radical initiator.

[0035] Preferably, the free radical initiator is a persulfate salt, azobisdimethylamid hydrochloride (AIBA, V-50 initiator), azobisdimethylimidazole hydrochloride (AIBI, VA-044 initiator), azobisdimethylvaleric acid (ACVA, V-501), or azobisdimethylimidazole (AIP, VA-061 initiator), and some of the compound structures are as follows:

[0036]

[0037] Preferably, the persulfate salt is selected from any one or a combination of at least two of sodium persulfate, potassium persulfate, or ammonium persulfate.

[0038] Preferably, the polymerization of the polyethylene glycol derivative modified by end group acrylamide and the ionic monomer is carried out by reverse suspension polymerization.

[0039] Preferably, the reverse suspension polymerization specifically comprises: configuring the polyethylene glycol derivative modified by end group acrylamide, the ionic monomer, and the free radical initiator into an aqueous phase solution; and adding the aqueous phase solution into an oil phase to carry out reverse suspension polymerization, thereby obtaining the water gel microspheres.

[0040] The reaction scheme can be represented as follows:

[0041]

[0042] Preferably, the oil phase is butyl acetate, petroleum ether, n-hexane, cyclohexane, or paraffin oil.

[0043] Preferably, 3-5% (3%, 3.5%, 4%, 4.5%, or 5%) of a surfactant is added to the oil phase.

[0044] Preferably, the surfactant comprises one or a mixture of two of cellulose acetate butyrate, Tween or Span.

[0045] Preferably, when the free radical initiator is a persulfate salt, a catalyst is additionally added to the oil phase.

[0046] Preferably, the catalyst comprises tetramethylethylenediamine and / or triethylamine.

[0047] Preferably, the temperature of the inverse suspension polymerization is 50-90℃, such as 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃ or 90℃.

[0048] Preferably, the time of the inverse suspension polymerization is 2-12h, such as 2h, 4h, 6h, 8h, 10h, 11h or 12h.

[0049] In the present application, the hydrogel microspheres dry balls are obtained after the inverse suspension polymerization is finished and dehydrated and dried.

[0050] In another aspect, the present application provides a drug-loaded microsphere, which comprises the hydrogel microspheres as described above and a drug loaded thereon.

[0051] Preferably, the drug comprises any one of doxorubicin hydrochloride, irinotecan, sun itinib, oxaliplatin, VC sodium, gemcitabine or 5-Fu (5-fluorouracil) or a combination of at least two of them.

[0052] The operation of loading the drug on the hydrogel microspheres of the present application is: adding the hydrogel microspheres into an aqueous solution containing the drug to obtain the drug-loaded microspheres.

[0053] The hydrogel microspheres dry balls of the present application can quickly adsorb the drug solution through swelling effect, realizing efficient, rapid and high loading of the drug; and the hydrogel microspheres have a relatively dense shell and ionic polymer chain structure, which has obvious sustained release effect on the drug molecules, especially the drug molecules with opposite electric charges, and can effectively regulate the release of the drug.

[0054] Compared with the prior art, the present application has the following beneficial effects:

[0055] The hydrogel microspheres of the present application have a super-hydrophilic core-shell structure, the shell layer is a relatively dense structure formed by polymerization of a large amount of polyethylene glycol derivative monomers, and the core layer is a relatively loose structure formed by polymerization of ionic monomers. The dense and highly hydrophilic polyethylene glycol derivative structure of the shell layer makes the microspheres have strong toughness and will not burst when swelling. After the microspheres are dehydrated and dried, dry balls are obtained. The dry hydrogel microspheres can quickly absorb drug solutions through swelling, achieving efficient, rapid and high-loading drug loading. The hydrogel microspheres of the present application have a relatively dense shell and ionic polymer chain structure, and have obvious sustained release effect on drug molecules, especially drug molecules with opposite electric charges, which can effectively regulate drug release. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 The figure is a schematic diagram of the structure of the hydrogel microspheres of the present application.

[0057] Figure 2 The figure is a schematic diagram of the internal cross-linked network structure of the hydrogel microspheres of the present application.

[0058] Figure 3 The figure is an optical microscope picture of the hydrogel microspheres prepared in Example 1.

[0059] Figure 4 The figure is an optical microscope picture of the hydrogel microspheres prepared in Example 2.

[0060] Figure 5 The figure is an optical microscope picture of the hydrogel microspheres prepared in Example 3.

[0061] Figure 6 The figure is an optical microscope picture of the hydrogel microspheres prepared in Example 4.

[0062] Figure 7 The figure is an optical microscope picture of the hydrogel microspheres prepared in Example 5.

[0063] Figure 8 The figure is an optical microscope picture of the hydrogel microspheres prepared in Example 6.

[0064] Figure 9 The figure is an optical microscope picture of the hydrogel microspheres prepared in Example 7.

[0065] Figure 10 The figure is an optical microscope picture of the hydrogel microspheres prepared in Example 8.

[0066] Figure 11 The figure is an optical microscope picture of the dry balls of the hydrogel microspheres of Example 2.

[0067] Figure 12 The figure is an optical microscope picture of the dry balls of the hydrogel microspheres of Example 2 after absorbing doxorubicin hydrochloride solution.

[0068] Figure 13 Drug release curve of hydrogel microspheres of Example 2 for doxorubicin hydrochloride.

[0069] Figure 14 Drug release curve of hydrogel microspheres of Example 7 for sodium salicylate. DETAILED DESCRIPTION

[0070] The technical solutions of the present application are further illustrated below by means of specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations on the present application.

[0071] Example 1

[0072] In this embodiment, the hydrogel microspheres are prepared by the following method:

[0073] Preparation of the oil phase: 3 g of cellulose acetate butyrate is added to 100 mL of butyl acetate, and the mixture is stirred to dissolve at 50°C to form a uniform oil phase system.

[0074] Preparation of the oil phase: 3 g of cellulose acetate butyrate is added to 100 mL of butyl acetate, and the mixture is stirred to dissolve at 50°C to form a uniform oil phase system.

[0075] Reverse suspension polymerization reaction: the prepared aqueous phase solution is slowly added to the oil phase solution under stirring at 50°C and 300 rpm to form a water-in-oil reverse suspension polymerization system. The reaction is maintained at 50°C for 30 minutes, then 1.0 mL of triethylamine (Et3N) is added to the oil phase, and the temperature is raised to 80°C for reaction for 4 hours.

[0076] Purification: after the reaction is completed, the obtained microspheres are repeatedly washed with butyl acetate, purified water and 5% sodium bicarbonate aqueous solution for 3-5 times to obtain the hydrogel microspheres.

[0077] The schematic structure of the obtained hydrogel microspheres is shown in Figure 1 The hydrogel microspheres have a core-shell structure, the shell layer is a relatively dense structure formed by polymerization of a large amount of polyethylene glycol monomer derivatives, and the core layer is a relatively loose structure formed by polymerization of ionic monomers. The schematic structure of the internal cross-linked network of the hydrogel microspheres is shown in Figure 2

[0078] Example 2

[0079] ​In this embodiment, the hydrogel microspheres are prepared by the following method:

[0080] Water phase preparation: 3.2 g of diethylene glycol diglycidyl ether was accurately weighed into a glass bottle, 6 mL of 12% NaOH aqueous solution was added, and it was stirred at room temperature on a magnetic stirrer for 0.5 h. 9.5 mL of 50% mass fraction of N-hydroxyethyl acrylamide aqueous solution was added to the bottle, and stirring was continued for 2 h. The system solution was neutralized to neutral with concentrated hydrochloric acid, and 6.5 g of sodium acrylate was added to the water solution, and after stirring for 0.5 h, 180 mg of ammonium persulfate was added, and after uniform stirring for 0.5 h, it was configured as the water phase.

[0081] Oil phase preparation: 3 g of cellulose acetate butyrate was added to 100 mL of butyl acetate, and the uniform oil phase system was dissolved by stirring at 50°C.

[0082] Reverse suspension polymerization reaction: the above prepared water phase solution was slowly added to the oil phase solution under the condition of stirring at 50°C and 300 rpm to form a water-in-oil reverse suspension polymerization system. Keep 50°C for 30 minutes, then add 1.2 mL of tetramethyl ethylenediamine (TMEDA) to the oil phase, and react at 80°C for 4 h.

[0083] Purification: after the reaction is completed, the obtained microspheres are washed repeatedly with butyl acetate, purified water and 5% sodium bicarbonate aqueous solution for 3-5 times to obtain hydrogel microspheres.

[0084] Example 3

[0085] In this embodiment, the hydrogel microspheres are prepared by the following method:

[0086] Water phase preparation: 3.2 g of diethylene glycol diglycidyl ether was accurately weighed into a glass bottle, 6 mL of 12% NaOH aqueous solution was added, and it was stirred at room temperature on a magnetic stirrer for 0.5 h. 9.5 mL of 50% mass fraction of N-hydroxyethyl acrylamide aqueous solution was added to the bottle, and stirring was continued for 2 h. The system solution was neutralized to neutral with concentrated hydrochloric acid, and 6.5 g of sodium acrylate was added to the water solution, and after stirring for 0.5 h, 180 mg of ammonium persulfate was added, and after uniform stirring for 0.5 h, it was configured as the water phase.

[0087] Oil phase preparation: 3 g of cellulose acetate butyrate was added to 100 mL of butyl acetate, and the uniform oil phase system was dissolved by stirring at 50°C.

[0088] Reverse suspension polymerization reaction: the above prepared water phase solution was slowly added to the oil phase solution under the condition of stirring at 50°C and 300 rpm to form a water-in-oil reverse suspension polymerization system. Keep 50°C for 30 minutes, then add 1.2 mL of tetramethyl ethylenediamine (TMEDA) to the oil phase, and react at 80°C for 4 h.

[0089] Purification: After the reaction, the microspheres were washed with butyl acetate, purified water and 5% sodium bicarbonate solution for 3-5 times to obtain the hydrogel microspheres.

[0090] Example 4

[0091] In this example, the hydrogel microspheres were prepared by the following method:

[0092] Preparation of the aqueous phase: 2.8 g of tetraethylene glycol diglycidyl ether was accurately weighed into a glass bottle, 6 mL of 20% KOH aqueous solution was added, and the mixture was stirred at room temperature on a magnetic stirrer for 0.5 h. 8.5 mL of 50% mass fraction of N-(2-hydroxypropyl) acrylamide aqueous solution was added to the bottle, and the stirring was continued for 2 h. The system solution was neutralized to neutral with concentrated hydrochloric acid, and 18 g of sodium methacrylate was added to the water solution. After stirring for 0.5 h, 120 mg of ammonium persulfate was added, and the mixture was uniformly stirred for 0.5 h to prepare the aqueous phase.

[0093] Preparation of the oil phase: 3 g of cellulose acetate butyrate was added to 100 mL of butyl acetate, and the mixture was dissolved at 50°C to form a uniform oil phase system.

[0094] Reverse suspension polymerization reaction: the prepared aqueous phase solution was slowly added to the oil phase solution under the condition of 50°C and 300 rpm stirring to form a water-in-oil reverse suspension polymerization system. The reaction was maintained at 50°C for 30 min, then 1.0 mL of triethylamine (Et3N) was added to the oil phase, and the temperature was raised to 85°C for 3.5 h.

[0095] Purification: After the reaction, the microspheres were washed with butyl acetate, purified water and 5% sodium bicarbonate solution for 3-5 times to obtain the hydrogel microspheres.

[0096] Example 5

[0097] In this example, the hydrogel microspheres were prepared by the following method:

[0098] Preparation of the aqueous phase: 2.8 g of tetraethylene glycol diglycidyl ether was accurately weighed into a glass bottle, 6 mL of 20% KOH aqueous solution was added, and the mixture was stirred at room temperature on a magnetic stirrer for 0.5 h. 8.5 mL of 50% mass fraction of N-(2-hydroxypropyl) acrylamide aqueous solution was added to the bottle, and the stirring was continued for 2 h. The system solution was neutralized to neutral with concentrated hydrochloric acid, and 18 g of sodium methacrylate was added to the water solution. After stirring for 0.5 h, 120 mg of ammonium persulfate was added, and the mixture was uniformly stirred for 0.5 h to prepare the aqueous phase.

[0099] Oil phase preparation: 3 g Span 80 and 1 g Tween 20 were added to 100 mL of n-hexane, and stirred to dissolve to form a uniform oil phase system at 50 °C.

[0100] Inverse suspension polymerization reaction: The water phase solution prepared above was slowly added to the oil phase solution to form an inverse suspension polymerization system with water in oil under stirring at 70 °C and 300 rpm. The reaction was maintained at 70 °C for 30 min, and then the temperature was increased to 90 °C for 6 h.

[0101] Purification: After the reaction was completed, the microspheres obtained were washed repeatedly 3-5 times with butyl acetate, purified water, and 5% aqueous sodium bicarbonate solution to obtain the hydrogel microspheres.

[0102] Example 6

[0103] In this example, the hydrogel microspheres were prepared by the following method:

[0104] Water phase preparation: 3.2 g of PEG500 diglycidyl ether was accurately weighed in a glass bottle, 10 mL of 25% NaOH aqueous solution was added, and the system was stirred at room temperature for 0.5 h on a magnetic stirrer. 10 mL of 50% mass fraction N-hydroxyethyl methacrylamide aqueous solution was added to the bottle, and stirring was continued for 2.5 h. The system solution was neutralized to neutral with concentrated hydrochloric acid, 7.9 g of sodium vinyl sulfonate was added to the water solution, and after stirring for 0.5 h, 150 mg of azobisdimethylimidazole hydrochloride (VA-044) was added. The system was stirred uniformly for 0.5 h to prepare the water phase.

[0105] Oil phase preparation: 3 g Span 80 and 1 g Tween 20 were added to 100 mL of n-hexane, and stirred to dissolve to form a uniform oil phase system at 50 °C.

[0106] Inverse suspension polymerization reaction: The water phase solution prepared above was slowly added to the oil phase solution to form an inverse suspension polymerization system with water in oil under stirring at 70 °C and 300 rpm. The reaction was maintained at 70 °C for 30 min, and then the temperature was increased to 90 °C for 6 h.

[0107] Purification: After the reaction was completed, the microspheres obtained were washed repeatedly 3-5 times with butyl acetate, purified water, and 5% aqueous sodium bicarbonate solution to obtain the hydrogel microspheres.

[0108] Example 7

[0109] In this example, the hydrogel microspheres were prepared by the following method:

[0110] Water phase preparation: 3.0 g of tetraethylene glycol diglycidyl ether was accurately weighed into a glass bottle, 6 mL of 10% NaOH aqueous solution was added, and the bottle was placed on a magnetic stirrer for stirring at room temperature for 0.5 h. 9 mL of 50% mass fraction of N-hydroxymethyl acrylamide aqueous solution was added to the bottle, and stirring was continued for 2 h. The system solution was neutralized to neutral with concentrated hydrochloric acid, and an aqueous solution containing 14 g of (3-acrylamidopropyl) trimethylammonium chloride was added. After stirring for 0.5 h, 100 mg of azobis (dicyanovinyl) acid (V-501) was added, and the mixture was stirred uniformly for 0.5 h to prepare the water phase.

[0111] Oil phase preparation: 3 g of Span 80 and 1 g of Tween 20 were added to 100 mL of paraffin oil, and the mixture was dissolved by stirring at 50°C to form a uniform oil phase system.

[0112] Reverse suspension polymerization reaction: The water phase solution prepared above was slowly added to the oil phase solution under stirring at 50°C and 400 rpm to form a water-in-oil reverse suspension polymerization system. The reaction was maintained at 50°C for 30 min and then the temperature was increased to 75°C for 5 h.

[0113] Purification: After the reaction was completed, the obtained microspheres were washed repeatedly 3-5 times with petroleum ether (30-60), butyl acetate, purified water, and 5% sodium bicarbonate aqueous solution to obtain the hydrogel microspheres.

[0114] Example 8

[0115] In this example, the hydrogel microspheres were prepared by the following method:

[0116] Water phase preparation: 3.0 g of tetraethylene glycol diglycidyl ether was accurately weighed into a glass bottle, 6 mL of 10% NaOH aqueous solution was added, and the bottle was placed on a magnetic stirrer for stirring at room temperature for 0.5 h. 9.2 mL of 50% mass fraction of N-hydroxymethyl acrylamide aqueous solution was added to the bottle, and stirring was continued for 2 h. The system solution was neutralized to neutral with concentrated hydrochloric acid, and an aqueous solution containing 15 g of (3-methacrylamidopropyl) trimethylammonium chloride was added. After stirring for 0.5 h, 130 mg of azobis (diisopropylimidazoline) (VA-061) was added, and the mixture was stirred uniformly for 0.5 h to prepare the water phase.

[0117] Oil phase preparation: 3 g of Span 80 and 1 g of Tween 20 were added to 100 mL of paraffin oil, and the mixture was dissolved by stirring at 50°C to form a uniform oil phase system.

[0118] Reverse suspension polymerization reaction: The water phase solution prepared above was slowly added to the oil phase solution under stirring at 50°C and 400 rpm to form a water-in-oil reverse suspension polymerization system. The reaction was maintained at 50°C for 30 min and then the temperature was increased to 75°C for 5 h.

[0119] Purification: After the reaction, the obtained microspheres were washed with petroleum ether (30-60), butyl acetate, purified water and 5% sodium bicarbonate solution for 3-5 times to obtain the hydrogel microspheres.

[0120] The hydrogel microspheres prepared in Examples 1-8 were characterized by scanning electron microscopy, and the results are shown in FIGS. 1-8, respectively. Figures 3-10 As can be seen, the hydrogel microspheres prepared by the scheme of the present application have a complete and smooth appearance, and under a Keyence (VHX-950F video display system) microscope, a single microsphere has a clear core-shell double-layer structure.

[0121] Performance test:

[0122] Dry ball preparation method: The hydrogel microspheres prepared in Examples 1-8 were added to acetone for shrinkage for multiple times, and then dried at 80°C for 3h to constant weight to obtain dry granular microspheres.

[0123] The optical microscope picture of the dry ball of the hydrogel microspheres of Example 2 is shown in FIG. 9. Figure 11 As can be seen, the microspheres after drying still maintain the complete structure without breaking.

[0124] Dry ball swelling speed test: 100mg of the dry ball of the hydrogel microspheres prepared in Examples 1-8 was taken in a 20mL vial, and 10mL of pure water, 0.9% NaCl aqueous solution or 5% glucose aqueous solution was added, and the time required for complete swelling was tested, and the results are shown in Table 1.

[0125] Table 1

[0126]

[0127] Dry ball drug loading test: The near-saturated aqueous solution of each drug was prepared, 2mL of drug solution was taken in a 10mL vial, and 50mg of the dry ball of each example was added, and the dry ball quickly swelled and absorbed the drug solution, and the scanning electron microscope picture of the dry ball of the hydrogel microspheres of Example 2 after absorbing the doxorubicin hydrochloride solution is shown in FIG. 10. Figure 12 As can be seen, the doxorubicin hydrochloride can quickly penetrate the shell layer of the hydrogel microspheres into the core of the microspheres, which is conducive to the slow release of the drug.

[0128] The amount of drug loaded by the hydrogel microspheres was calculated according to the absorption volume and the drug concentration. The test results of the drug loading amount are shown in Table 2.

[0129] Table 2

[0130]

[0131]

[0132] As can be seen from Table 2, the hydrogel microspheres prepared according to the present application have good broad-spectrum drug loading function, and compared with the microspheres that can only load a single type of drug, the use range of the microspheres is expanded.

[0133] Drug release test:

[0134] The drug-loaded hydrogel microspheres were transferred to 37°C, 20 mL of normal saline for drug release test, and the extraction liquid was replaced at 30 minutes, 1 hour, 2 hours, 3 hours, 24 hours, 48 hours, 72 hours, 90 hours and 102 hours, and the concentration of the drug in the extraction liquid was measured to calculate the cumulative drug release amount.

[0135] The drug release curve of the hydrogel microspheres of Example 2 for doxorubicin hydrochloride is shown in Figure 13 As can be seen, the hydrogel microspheres with carboxylate anions have excellent sustained release effect for the cationic drug doxorubicin hydrochloride, with a release rate of 41.4% within 29 hours, achieving sustained slow release.

[0136] The drug release curve of the hydrogel microspheres of Example 7 for sodium salicylate is shown in Figure 14 As can be seen, the hydrogel microspheres with quaternary amine cations have excellent sustained release effect for the anionic drug sodium salicylate, with a release rate of less than 50% within 120 hours, achieving sustained slow release.

[0137] The wet microspheres obtained in Example 2 were finely screened by a screen to obtain three specifications of 40-100 μm, 100-200 μm and 200-300 μm (ultralimit ratio <5%), and three batches of dry-swelling operations were cumulatively performed, and the particle size change of the dry microspheres of each batch after being fully swelled in pure water, 0.9% NaCl solution and 5 mg / mL doxorubicin hydrochloride solution was compared, and the statistical data are shown in Table 3.

[0138] Sampling and swelling standard: the initial wet ball volume is 1 mL; the dry ball mass is 100 mg; the immersion aqueous solution volume is 15 mL.

[0139] Average particle size test method: the above optical microscope was used, all the microspheres in two fields of view were included in the statistics, and the total number of microspheres was required to be greater than 150, and if less than 150, another field of view of microspheres was taken; the instrument operation software was used to manually test the particle sizes of all the microspheres included in the statistics, the values were recorded and the average particle size was calculated.

[0140] Table 3

[0141]

[0142] As can be seen from Table 3 above, the wet microsphere diameter of the present application has no change before and after drying, and after three times of drying-swelling, the microsphere morphology is still complete, without broken or burst microspheres, and the particle size remains unchanged compared with before drying, which embodies that the hydrogel microspheres of the present application have excellent mechanical properties and toughness.

[0143] Applicants declare that the hydrogel microspheres of the present application, the preparation method and the application thereof are illustrated by the above examples, but the present application is not limited to the above examples, i.e. it does not mean that the present application must rely on the above examples to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of the raw materials selected by the present application, addition of auxiliary ingredients, selection of specific modes, etc. all fall within the protection scope and disclosure scope of the present application.

Claims

1. A hydrogel microsphere, characterized in that, The hydrogel microspheres have a core-shell structure, comprising a shell formed by a polyethylene glycol derivative modified with acrylamide end groups, and a core formed by polymerized segments of ionic monomers; The acrylamide-terminated polyethylene glycol derivative has the structure shown in Formula I: ； R1 and R2 are independently selected from H, C1-C4 alkyl groups, and -(CH2). q -OH; n = 1-12 integers, R3 is selected from H or -CH3, m = 1 or 2, q is 1 or 2; The ionic monomer is selected from sodium acrylate, sodium methacrylate, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), sodium p-styrene sulfonate, sodium vinyl sulfonate, (3-acrylamidopropyl)trimethylammonium chloride, and (3-methacrylamidopropyl)trimethylammonium chloride. The hydrogel microspheres are prepared by the following method, which includes: polymerizing a polyethylene glycol derivative modified with acrylamide end groups with an ionic monomer to obtain the hydrogel microspheres; The polymerization of the acrylamide-terminated polyethylene glycol derivative with the ionic monomer is carried out by reverse suspension polymerization. The reverse suspension polymerization specifically involves: preparing an aqueous solution of a polyethylene glycol derivative modified with acrylamide end groups, an ionic monomer, and a free radical initiator; adding the aqueous solution to an oil phase for reverse suspension polymerization to obtain the hydrogel microspheres.

2. The hydrogel microspheres according to claim 1, characterized in that, The method for preparing the acrylamide-terminated polyethylene glycol derivative includes the following steps: The glycidyl ether compound shown in Formula II reacts with the N-hydroxyalkylacrylamide compound shown in Formula III to obtain the polymer shown in Formula I, as shown in the following reaction formula: 。 3. The hydrogel microspheres according to claim 2, characterized in that, The glycidyl ether compound represented by Formula II is selected from any one or a combination of at least two of ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, tetraethylene glycol diglycidyl ether, PEG200 diglycidyl ether or PEG500 diglycidyl ether. The N-hydroxyalkyl acrylamide compounds are selected from N-hydroxymethyl acrylamide, N-hydroxyethyl acrylamide, N-[tris(hydroxymethyl)methyl]acrylamide, N-(2-hydroxypropyl)acrylamide, N-(hydroxymethyl)methylacrylamide, N-(hydroxyethyl)methylacrylamide, N-[tris(hydroxymethyl)methyl]methylacrylamide or N-(2-hydroxypropyl)methylacrylamide; The reaction is carried out in the presence of an alkaline substance; The alkaline substance is sodium hydroxide and / or potassium hydroxide; The reaction is carried out at room temperature; The reaction time is 1-6 hours.

4. The hydrogel microspheres according to claim 1, characterized in that, The hydrogel microspheres have a particle size of 30-1400 μm.

5. A method for preparing hydrogel microspheres as described in any one of claims 1-4, characterized in that, The preparation method includes: polymerizing a polyethylene glycol derivative modified with acrylamide end groups with an ionic monomer to obtain the hydrogel microspheres; The polymerization of the acrylamide-terminated polyethylene glycol derivative with the ionic monomer is carried out by reverse suspension polymerization. The reverse suspension polymerization specifically involves: preparing an aqueous solution of a polyethylene glycol derivative modified with acrylamide end groups, an ionic monomer, and a free radical initiator; adding the aqueous solution to an oil phase for reverse suspension polymerization to obtain the hydrogel microspheres.

6. The preparation method according to claim 5, characterized in that, The amount of the ionic monomer used is 1-8 times the molar amount of the acrylamide-terminated polyethylene glycol derivative; The polymerization of the acrylamide-terminated polyethylene glycol derivative with ionic monomers is carried out under the initiation of a free radical initiator; The free radical initiator is persulfate, azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobisisobutylammonium valerate, or azobisisopropylimidazoline; The persulfate is selected from any one or a combination of at least two of sodium persulfate, potassium persulfate, or ammonium persulfate.

7. The preparation method according to claim 5, characterized in that, The oil phase is butyl acetate, petroleum ether, n-hexane, cyclohexane, or paraffin oil; Add 3-5% by mass of surfactant to the oil phase; The surfactant includes one or a mixture of two of cellulose acetate butyrate, Tween or Span; When the free radical initiator is a persulfate, an additional catalyst is added to the oil phase; The catalyst comprises tetramethylethylenediamine and / or triethylamine; The temperature for the reverse suspension polymerization is 50-90℃; The reverse suspension polymerization time is 2-12 hours.

8. A drug-loaded microsphere, characterized in that, The drug-loaded microspheres include hydrogel microspheres as described in any one of claims 1-4 and the drug loaded thereon; The drugs include any one or a combination of at least two of the following: doxorubicin hydrochloride, irinotecan, sunitinib, oxaliplatin, sodium ascorbate, gemcitabine, or 5-fluorouracil.

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