Gastric retention drug-loaded magnetic microprojectile and its preparation method and application

Abstract

The present invention discloses a gastric retention drug-loaded magnetic microbullet and its preparation method and application. It relates to the field of biomedicine technology. It comprises a microbullet shell, a magnet block and a drug. Under the guidance of an external magnetic field, the present invention can achieve positioning and long-term retention in the stomach, while slowly and continuously releasing drugs in the stomach to treat gastric diseases, avoiding the problem that gastric diseases are difficult to cure due to low drug concentration in the lesion site. By adjusting the number and aperture of the small holes at the bottom of the microbullet shell, the drug release rate can be adjusted, and personalized design can be made according to the needs of different diseases, and the retention time of the drug-loaded magnetic microbullet in the stomach can be controlled. After the drug-loaded magnetic microbullet has released the drug, the external magnet block is removed, and the drug-loaded magnetic microbullet is discharged from the body through the peristalsis of the gastrointestinal tract.

Description

Technical Field

[0001] The present invention relates to the field of biomedicine technology, and more particularly to a gastric retention drug-loaded magnetic microprojectile and a preparation method and application thereof. Background Art

[0002] Helicobacter pylori is a microaerophilic bacterium that parasitizes the submucous layer of the stomach and can cause diseases such as gastritis, gastric ulcers, and even gastric cancer. Currently, the main clinical treatment for Helicobacter pylori infection is oral antibiotics, such as amoxicillin, clarithromycin, and furazolidone, combined with proton pump inhibitors and bismuth. However, the main drawback of traditional oral preparations is that the drugs have a short residence time in the stomach and it is difficult to maintain effective concentrations in the stomach. The only way to achieve the purpose of treating Helicobacter pylori is to take multiple drugs in frequent, high-dose doses. In addition, some patients who take large amounts of antibiotics for a long time may experience adverse reactions such as nausea, vomiting, and diarrhea, which may lead to patients stopping the medication without authorization, interrupting the treatment course, and increasing the drug resistance of Helicobacter pylori. Therefore, the development of safe and effective anti-Helicobacter pylori preparations is of great clinical significance.

[0003] Prolonging the gastric retention time of traditional oral antibiotics is a key issue in improving their efficacy against Helicobacter pylori. Currently, floating tablets are the most commonly used gastric retention drug delivery systems in clinical practice. However, these systems require a strict drug-to-floating material ratio, which cannot be adjusted promptly based on disease treatment needs and patient characteristics. Furthermore, tablet dissolution reduces the floating capacity, making gastric retention time difficult to control and reducing drug utilization.

[0004] Therefore, whether or not a gastric retention drug delivery system with controllable gastric retention time can be developed is the key to achieving efficient elimination of Helicobacter pylori and is also a problem that those skilled in the art urgently need to solve. Summary of the Invention

[0005] In light of this, the present invention provides a gastric-retention drug-loaded magnetic microprojectile, its preparation method, and application. The design and preparation of a drug-loaded magnetic microprojectile allows it to be positioned and retained in the stomach for extended periods under the guidance of an external magnetic field. It then slowly and continuously releases the drug in the stomach, treating gastric diseases and avoiding the difficulty in curing gastric diseases due to low drug concentrations at the lesion site.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A gastric retention drug-loaded magnetic microbullet comprises a microbullet shell, a magnet block, and a drug. The main body of the microbullet shell is a hollow cylindrical structure, the bottom of the cylinder is a closed thin sheet with small holes passing through the sheet, and microneedles with needle tips pointing upward are evenly distributed on the top ring of the hollow cylindrical structure.

[0008] The cavity portion of the hollow cylindrical structure is loaded with the medicine; and the magnet block is horizontally placed on the medicine.

[0009] Preferably, the length of the micro-bullet shell is selected from 0.2 cm to 2.5 cm; the inner diameter of the micro-bullet shell is selected from 0.1 cm to 1 cm; and the outer diameter of the micro-bullet shell is selected from 0.12 cm to 1.02 cm.

[0010] The thickness of the sheet is 0.05mm~0.1mm;

[0011] The number of the through holes is selected from 1 to 4, and the diameter of the through holes is 0.1 mm to 0.5 mm;

[0012] The shape of the microneedles is selected from conical, cylindrical, triangular or quadrangular, and the number is selected from 3 to 15;

[0013] The drugs include: clarithromycin, amoxicillin, tetracycline, metronidazole, rifamycin, furazolidone, levofloxacin, ciprofloxacin, preferably any one or a combination of clarithromycin, amoxicillin, and levofloxacin.

[0014] Preferably, the length of the micro-bullet shell is selected from 0.2 cm to 1 cm;

[0015] The inner diameter of the micro-shell is selected from 0.1 cm to 0.6 cm;

[0016] The outer diameter of the micro-bullet shell is selected from 0.12 cm to 0.62 cm.

[0017] The microneedle is in the form of a tapered microneedle; the height of the tapered microneedle is selected from 0.2 mm to 1.5 mm; the bottom circular diameter of the tapered microneedle is selected from 0.2 mm to 3 mm;

[0018] Drug: Clarithromycin and 2-O-α-D-glucopyranosyl-L-ascorbic acid were mixed uniformly at a mass ratio of 2.2:1 and ground for 30 minutes to obtain a ground mixture of clarithromycin and 2-O-α-D-glucopyranosyl-L-ascorbic acid.

[0019] The present invention also provides a method for preparing any of the above-mentioned gastric-retaining drug-loaded magnetic microprojectiles, which are prepared by a mold perfusion curing method or a 3D printing method.

[0020] Preferred: 3D printing method: fused deposition modeling 3D printing method or light-curing 3D printing method.

[0021] Preferred: Light-curing 3D printing method: According to the model parameters of the micro-bullet shell designed by computer, the printing solution is cured layer by layer from the material tank of the molding equipment onto the printer platform to prepare the micro-bullet shell.

[0022] Preferably, the photocuring 3D printing method comprises the following steps: according to the model parameters of the micro-cartridge designed by the computer, a printing solution is printed from the material tank of the molding equipment and solidified layer by layer onto the printer platform to prepare the micro-cartridge; the cavity portion of the hollow cylindrical structure of the micro-cartridge is loaded with a drug; the drug is filled into the micro-cartridge through the top opening of the micro-cartridge; after the drug is filled into the micro-cartridge, a magnet block is placed horizontally above the drug, and the micro-cartridge 3D printing solution is used as a bonding material and dripped into the gap between the magnet block and the inner wall of the hollow cylinder of the micro-cartridge; the micro-cartridge is quickly placed under a 405nm laser light source for irradiation and curing, and the drug and the magnet block are encapsulated into the micro-cartridge to form a complete drug-loaded magnetic micro-cartridge.

[0023] Preferably, the printing solution is selected from acrylic acid, methyl acrylate, polypropylene fumarate, polyethylene glycol diacrylate, N-vinyl pyrrolidone, and silicone.

[0024] Preferred: any one of the printing solutions Dental SG, Dental LT Clear V2 resin, BioMed Clear resin, and BioMed Amber resin.

[0025] The present invention also provides the use of any of the above-mentioned gastric-retention drug-loaded magnetic microprojectiles, or any of the above-mentioned preparation methods in the preparation of drugs or diagnostic and treatment equipment.

[0026] Furthermore: the drug filling volume is set according to the disease treatment needs, but does not exceed the top edge of the micro-shell.

[0027] The small holes at the bottom of the microcartridge can control the release of loaded drugs. The larger the aperture of the small holes and the more the number of small holes, the faster the drug is released.

[0028] After swallowing, the drug-loaded magnetic microbullet is attracted by the magnetic field of a magnet pre-placed on the skin corresponding to the stomach and reaches the corresponding location within the stomach. Adjusting the position of the external magnet can control the specific location of the stomach where the drug-loaded magnetic microbullet reaches, generally aiming to reach the pylorus and then remain near it. Because the north and south poles of the internal magnet are known, adjusting the orientation of the external magnet allows the drug-loaded magnetic microbullet's microneedles to face the stomach wall and penetrate the gastric mucosa.

[0029] It can be seen from the above technical solutions that, compared with the prior art, the present invention provides a gastric retention drug-loaded magnetic microprojectile and its preparation method and application, and the technical effects achieved are:

[0030] Guided by an external magnetic field, the drug can be located and retained in the stomach for extended periods, while slowly and continuously releasing the drug there to treat gastric diseases. This avoids the difficulty in curing gastric diseases due to low drug concentrations at the lesion site, effectively treating various gastric diseases, including gastric cancer, gastric ulcers, gastritis, and Helicobacter pylori infection. In particular, drug-loaded magnetic microprojectiles, when used to treat Helicobacter pylori infection, can improve the eradication rate of Helicobacter pylori, reduce gastric tissue damage, and reduce the recurrence rate of Helicobacter pylori infection.

[0031] By adjusting the number and size of the small holes at the bottom of the microbullet shell, the drug release rate can be adjusted, and personalized design can be made for different disease needs. The retention time of the drug-loaded magnetic microbullet in the stomach can be controlled. After the drug-loaded magnetic microbullet has released the drug, the external magnet block is removed, and the drug-loaded magnetic microbullet is excreted from the body through the peristalsis of the gastrointestinal tract. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0033] Figure 1 The accompanying figure is a 3D printing design diagram of the micro-bullet shell provided by the present invention.

[0034] Figure 2 The accompanying figure is a physical picture of the 3D printed micro cartridge case provided by the present invention.

[0035] Figure 3 The accompanying drawing is a schematic diagram of the drug-loaded magnetic microprojectile provided by the present invention.

[0036] Figure 4 The accompanying drawing is a schematic diagram of the appearance of the drug-loaded magnetic microprojectile provided by the present invention.

[0037] Figure 5 The accompanying drawings are scanning electron microscope images of 3D printed micro-cartridges with different aperture combinations provided by the present invention.

[0038] Figure 6 The accompanying figure is a schematic diagram of the force-displacement curve of the tip of the 3D printed micro-bullet (type 300 / 4) provided by the present invention.

[0039] Figure 7 The accompanying drawings are scanning electron micrographs provided by the present invention, wherein CAM: clarithromycin; AA-2G: 2-O-α-D-glucopyranosyl-L-ascorbic acid; CPM: clarithromycin physical mixture; CGM: clarithromycin grinding mixture, the same below.

[0040] Figure 8 The accompanying drawing is an infrared spectrum provided by the present invention.

[0041] Figure 9 The accompanying drawing is an X-ray diffraction pattern provided by the present invention.

[0042] Figure 10 The accompanying drawing is a differential scanning calorimetry diagram provided by the present invention.

[0043] Figure 11 The accompanying drawing is a schematic diagram of the solubility of clarithromycin before and after solubilization provided by the present invention.

[0044] Figure 12 The accompanying drawings are graphs showing the growth inhibition of Helicobacter pylori by different concentrations of clarithromycin and its grinding mixture provided by the present invention, wherein BHI: brain heart infusion medium, blank control.

[0045] Figure 13 The accompanying drawings are schematic diagrams of the cumulative release curves provided by the present invention, wherein A: clarithromycin-loaded microbullets; B: clarithromycin-loaded milled mixture microbullets; C: cumulative release rate of clarithromycin from clarithromycin-loaded microbullets and clarithromycin-loaded milled mixture microbullets at 24 hours.

[0046] Figure 14 The accompanying drawings are X-ray images of the microprojectiles provided by the present invention, wherein MG: magnetic guidance group; NMG: non-magnetic guidance group; the circle represents the stomach, the arrow represents the microprojectile, and the square represents the ear tag.

[0047] Figure 15 The accompanying drawings show the retention of microprojectiles in mice at different time points in the magnetic guidance group (MG) and the non-magnetic guidance group (NMG) provided by the present invention. The black block on the abdomen represents the external magnet, the circle represents the stomach, and the arrow points to the microprojectile.

[0048] Figure 16 The attached figure shows the depth of the microneedle on the top of the magnetic microbullet provided by the present invention puncturing the mouse stomach tissue and the H&E stained section of the stomach tissue after healing.

[0049] Figure 17 The accompanying figure is a complete shell diagram of the magnetic microprojectile excreted with feces provided by the present invention.

[0050] Figure 18 The accompanying drawings are schematic diagrams of the magnetically guided microprojectiles provided by the present invention being injected into an agarose gel block (A) and into the pyloric position (B); the boxes represent the microprojectiles, and the arrows represent the micropores left after the microneedles of the microprojectiles have penetrated the gel block and are removed.

[0051] Figure 19The accompanying drawings are H&E-stained sections of gastric tissue of mice infected with Helicobacter pylori treated with the drug-loaded magnetic microbullets provided by the present invention, wherein Healthy: healthy group; Model: model group (infected with Helicobacter pylori, not treated); CAM: clarithromycin group (infected with Helicobacter pylori, orally administered with clarithromycin suspension); CGM: clarithromycin grinding mixture group (infected with Helicobacter pylori, orally administered with clarithromycin grinding mixture solution); CMMB: drug-loaded magnetic microbullet group (infected with Helicobacter pylori, orally administered with one CMMB), the same below.

[0052] Figure 20 The accompanying figure is a WS-stained section of gastric tissue of mice infected with Helicobacter pylori treated with clarithromycin magnetic microbullets provided by the present invention.

[0053] Figure 21 The accompanying drawing is a schematic diagram of the content of Helicobacter pylori in gastric tissue provided by the present invention. DETAILED DESCRIPTION

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0055] The embodiment of the present invention discloses a gastric retention drug-loaded magnetic microprojectile, a preparation method and an application thereof.

[0056] The preparation processes not mentioned in the examples are conventional processes, and the sources of raw materials not mentioned are all commercially available conventional sources, which will not be described in detail here.

[0057] Example 1

[0058] Gastric retention drug-loaded (clarithromycin, CAM) magnetic microprojectiles

[0059] Microprojectile casing preparation: The microprojectile casing was prepared using conventional light-curing 3D printing methods. Using 3D design software, a device consisting of a hollow cylindrical structure, a thin sheet with holes at the bottom of the cylinder, and microneedles evenly distributed on a ring at the top of the cylinder wall with upward-pointing needles was designed. This design was then converted into a parameter file recognizable by a 3D printer. A Dental SG resin solution, suitable for dental surgical guides, was poured into the resin tank of the light-curing printer (at room temperature). The target file was selected and the microprojectile casing was printed. The microprojectile casing was removed from the platform, cleaned of any residual printing solution on the surface, dried, and then post-cured under a 405nm light source to produce a hard microprojectile casing.

[0060] The micro-bullet includes: a micro-bullet shell, a magnet block and medicine;

[0061] The main body of the microcartridge is a hollow cylindrical structure. The bottom of the cylinder is a closed thin sheet with small holes running through it. Microneedles with their tips pointing upwards are evenly distributed on the top ring of the cylinder wall.

[0062] To further optimize the technical solution: the thickness of the sheet is 0.05mm-0.1mm (0.08mm in this embodiment), the number of through holes is selected from 1 to 4 (4 in this embodiment), and the diameter of the through holes is 0.1mm-0.5mm (0.3mm in this embodiment);

[0063] The number of microneedles is selected from 3 to 15 (8 in this embodiment);

[0064] The length of the micro-shell is selected from 0.2 cm to 2.5 cm, and can be personalized designed and prepared according to the patient's esophagus and disease treatment needs (3.4 mm in this embodiment), the inner diameter of the micro-shell is selected from 0.1 cm to 1 cm (1.6 mm in this embodiment), and the outer diameter of the micro-shell is selected from 0.12 cm to 1.02 cm (2 mm in this embodiment).

[0065] The microneedle in this embodiment is conical in shape. The microneedle can penetrate the gastric mucosal tissue under the action of magnetic force, so that the microprojectile is fixed in a specific position and prevented from moving under the action of gastric mucus.

[0066] The height of the tapered microneedle is selected from 0.2 mm to 1.5 mm, preferably from 0.5 mm to 1 mm (0.9 mm in this embodiment); the bottom circular diameter of the tapered microneedle is selected from 0.2 mm to 3 mm (0.3 mm in this embodiment). The height and bottom area of ​​other types of microneedles can be designed accordingly with reference to the tapered microneedle.

[0067] Magnet block: round built-in magnet (1350GS in this embodiment, 1mm diameter, 0.5mm height);

[0068] Assembly of drug-loaded (clarithromycin) magnetic microprojectiles: The cavity of the microprojectile shell is filled with drug (clarithromycin powder). The internal magnet block is then placed horizontally above the drug powder. A small amount of printing solution (Dental SG resin solution) is dripped into the gap between the internal magnet block and the microprojectile shell. The microprojectile is then quickly cured under a 405nm light source. The drug and magnet are then encapsulated in the microprojectile shell to obtain the drug-loaded (clarithromycin) magnetic microprojectile.

[0069] To further optimize the technical solution, different modeling methods can produce microcartridges with different numbers and diameters of bottom drug-releasing holes. When the number of holes is 2 and the hole diameter is 200μm, a 200 / 2 microcartridge is obtained; when the number of holes is 4 and the hole diameter is 200μm, a 200 / 4 microcartridge is obtained; when the number of holes is 2 and the hole diameter is 300μm, a 300 / 2 microcartridge is obtained; and when the number of holes is 4 and the hole diameter is 300μm, a 300 / 4 microcartridge is obtained.

[0070] The gastric retention drug (clarithromycin) magnetic micro-flick of this embodiment is 300 / 4 type.

[0071] To further optimize the technical solution: the above-mentioned printing material can be replaced with other photopolymerizable substances, and the drug (clarithromycin) can be replaced with other drugs.

[0072] Figure 1 This is the 3D printed design of the micro-bullet case of this embodiment (specifically the 300 / 4 type micro-bullet case). The actual photo is shown in Figure 2 (The rice grains on the right are for size indication).

[0073] Example 2

[0074] Preparation method of gastric retention drug-loaded (clarithromycin and 2-O-α-D-pyranosyl-L-ascorbic acid, i.e., AA-2G, the same below) magnetic microprojectiles

[0075] Micro-bullet shell preparation: Micro-bullet shells are prepared using a light-curing 3D printing method: Using 3D design software, a device consisting of a hollow cylindrical structure, a thin sheet with holes at the bottom of the cylinder, and microneedles evenly distributed on the top ring of the cylinder wall with upward-pointing needles is designed. This is then converted into a parameter file recognizable by a 3D printer. At room temperature, a (Dental) SG resin solution, which can be used for dental surgical guides, is poured into the resin tank of the light-curing printer. The target file is selected and the micro-bullet shell is printed. The micro-bullet shell is removed from the platform, cleaned of any residual printing solution on the surface, dried, and then cured under a 405nm light source to produce a hard micro-bullet shell.

[0076] Assembly of drug-loaded (clarithromycin and 2-O-α-D-glucopyranosyl-L-ascorbic acid) magnetic microprojectiles: Clarithromycin and 2-O-α-D-glucopyranosyl-L-ascorbic acid were mixed at a mass ratio of 2.2:1 and ground for 30 minutes to obtain a ground mixture of clarithromycin and 2-O-α-D-glucopyranosyl-L-ascorbic acid (CGM).

[0077] The micro-bullet includes: a micro-bullet shell, a magnet block and medicine;

[0078] The main body of the microcartridge is a hollow cylindrical structure. The bottom of the cylinder is a closed thin sheet with small holes running through it. Microneedles with their tips pointing upwards are evenly distributed on the top ring of the cylinder wall.

[0079] To further optimize the technical solution: the thickness of the sheet is 0.05mm to 1mm (0.08mm in this embodiment), the number of the through holes is selected from 1 to 4 (4 in this embodiment), and the diameter of the through holes is 0.1mm to 0.5mm (0.3mm in this embodiment);

[0080] The number of microneedles is selected from 3 to 15 (8 in this embodiment);

[0081] The length of the micro-shell is selected from 0.2cm to 2.5cm (3.4mm in this embodiment), the inner diameter of the micro-shell is selected from 0.1cm to 1cm (1.6mm in this embodiment), and the outer diameter of the micro-shell is selected from 0.12cm to 1.02cm (2mm in this embodiment).

[0082] The microneedle is conical in shape; the height of the conical microneedle is selected from 0.2 mm to 1.5 mm (0.9 mm in this embodiment); the bottom circular diameter of the conical microneedle is selected from 0.2 mm to 3 mm (0.3 mm in this embodiment).

[0083] Magnet block: round built-in magnet (1350GS in this embodiment, 1mm diameter, 0.5mm height);

[0084] Assembly of drug-loaded (clarithromycin) magnetic microprojectiles: The cavity of the microprojectile shell is filled with drug (clarithromycin powder). The internal magnet block is then placed horizontally above the drug powder. A small amount of printing solution (Dental SG resin solution) is dripped into the gap between the internal magnet block and the microprojectile shell. The microprojectile is then quickly cured under a 405nm light source. The drug and magnet are then encapsulated in the microprojectile shell to obtain the drug-loaded (clarithromycin) magnetic microprojectile.

[0085] To further optimize the technical solution, different modeling methods can produce microcartridges with different numbers and diameters of bottom drug-releasing holes. When the number of holes is 2 and the hole diameter is 200μm, a 200 / 2 microcartridge is obtained; when the number of holes is 4 and the hole diameter is 200μm, a 200 / 4 microcartridge is obtained; when the number of holes is 2 and the hole diameter is 300μm, a 300 / 2 microcartridge is obtained; and when the number of holes is 4 and the hole diameter is 300μm, a 300 / 4 microcartridge is obtained.

[0086] The cavity of the microcartridge was filled with CGM powder, and the built-in magnet block was placed horizontally above the drug powder. A small amount of printing solution was dripped into the gap between the built-in magnet block and the microcartridge, and then quickly placed under a 405nm light source for curing. The drug and magnet were encapsulated into the microcartridge to obtain drug-loaded (clarithromycin and 2-O-α-D-pyranosyl-L-ascorbic acid) magnetic microcartridges.

[0087] The schematic diagram of the assembly of 300 / 4 drug-loaded (clarithromycin and 2-O-α-D-glucopyranosyl-L-ascorbic acid) magnetic microprojectiles is shown in Figure 3 , see the appearance photos Figure 4 , abbreviated as CMMB.

[0088] Technical effect verification:

[0089] 1. Properties of Micro-Casings

[0090] Materials: Micro-cartridge casing prepared according to Example 1.

[0091] Methods: Samples were examined for morphology using a scanning electron microscope (SEM) at an accelerating voltage of 20 kV. The mechanical strength of the needle tip was analyzed using an electronic universal testing machine at a compression rate of 0.15 mm / min. The test was terminated when the displacement reached 800 μm, and a force-displacement curve was plotted.

[0092] Results: SEM images are shown in Figure 5 As shown in the figure, the 3D printed micro-shell structure is complete, the main body is hollow, and 8 microneedles of equal size are evenly distributed on the top of the hollow cylinder. From the top view, it can be observed that the microneedle tips are sharp and have a clear layered structure. Figure 5 Middle A. The bottom hole structure of different types of micro-shells is complete, see Figure 5 Middle B illustrates that the embodiment uses light-curing 3D printing technology with sufficient precision to successfully print sharp microneedles to provide better penetration performance and ability while reducing damage to tissues, while the micropores at the bottom provide a release channel for the drug.

[0093] After mechanical compression testing, the micro-bullet needle tip structure of the present invention showed excellent mechanical properties, with a compressive strength of 56.83N. Figure 6 , indicating that the micro-bullet shell of the present invention not only has sufficient hardness to penetrate the gastric mucosa, but also has sufficient strength to withstand various stresses that may occur during the drug release process.

[0094] 2. Characterization of Clarithromycin Grinding Mixture

[0095] Materials: clarithromycin (CAM); 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G); Helicobacter pylori.

[0096] Methods: CAM and AA-2G (CAM:AA-2G = 2.2:1.0, w / w) were briefly mixed to obtain a CAM and AA-2G physical mixture (CPM, where CAM:AA-2G = 2.2:1.0, w / w). CAM and AA-2G (CAM:AA-2G = 2.2:1.0, w / w) were mixed and ground for 30 min to obtain a CAM and AA-2G ground mixture (CGM, where CAM:AA-2G = 2.2:1.0, w / w).

[0097] The samples were observed by SEM with an accelerating voltage of 20 kV. The samples were analyzed by Fourier transform infrared spectrometer with a scanning range of 4000 cm -1 ~650cm -1 , with a resolution of 1cm -1 The samples were analyzed by X-ray diffractometer with Cu Kα as the radiation source, wavelength of 1.5418 nm, voltage of 40 kV, current of 40 mA, scanning range (2θ) of 5° to 50°, scanning step of 0.02°, and scanning speed of 2° / min. The samples were measured by differential scanning calorimetry under the conditions of N2 purge, flow rate of 60 mL / min, heating range of 30°C to 400°C, and heating rate of 10°C / min. The solubility of CAM in the samples was determined by sulfuric acid colorimetry.

[0098] CAM and CGM powders were accurately weighed and the inhibitory effects of different concentrations of the drug solution on Helicobacter pylori were determined. The concentrations investigated were calculated based on the CAM content, which were 0.5, 0.25, 0.125, and 0.0625 μg / mL, respectively. 990 μL of the drug solution was mixed with 10 μL of fresh Helicobacter pylori solution (OD 600 =1) co-incubation, cultured at 37°C in a microaerobic environment; negative control, brain heart infusion medium (containing 10% fetal bovine serum) and bacterial solution were co-incubated, removed after 24 hours, and 100 μL of the bacterial solution was transferred to a blood agar plate after 100-fold dilution. After incubation at 37°C in a microaerobic environment for 48 hours, the growth of the cultured colonies was observed. The MIC was the drug concentration contained in the plate on which no colonies grew.

[0099] Results: SEM images showed that after grinding CAM and AA-2G, the columnar crystals of CGM disappeared and the particle size decreased, showing an amorphous powder. Figure 7 .

[0100] Infrared spectra show that the carbonyl stretching vibration peak of CAM in CGM shifts to higher wavenumbers, see Figure 8 , indicating that hydrogen bonding occurred between AA-2G and CAM during the grinding process.

[0101] The X-ray diffraction pattern shows that the characteristic peak of CAM in CGM disappears. Figure 9This indicates that CAM may be affected by factors such as hydrogen bonding and shear force during the grinding process, and the crystals are transformed into amorphous substances.

[0102] The differential scanning calorimetry (DSC) graph showed that CAM had sharp endothermic peaks at 227.67°C and 301.33°C. CPM only had an endothermic peak at 186.67°C, while CGM had an endothermic peak at 189.67°C. Compared with CPM, the endothermic peak shifted to the right, as shown in Figure 2. Figure 10 , indicating that CAM exists in an amorphous state in CGM, which is conducive to the increase of solubility.

[0103] Solubility results showed that the water solubility of CAM in CGM was greatly improved, reaching 2526 μg / mL, while the water solubility of pure CAM was 27 μg / mL. Figure 11 The high solubility of CGM is conducive to the release of CAM.

[0104] From the growth of Helicobacter pylori on blood agar plates, it can be seen that the minimum inhibitory concentration of CAM and CGM is 0.5 μg / mL (calculated based on CAM). Figure 12 , indicating that the auxiliary materials in the grinding process have no effect on the anti-Helicobacter pylori ability of CAM in CGM.

[0105] 3. In vitro drug release of drug-loaded magnetic microprojectiles

[0106] Materials: CAM, CGM, 200 / 2 micro-cartridge case; 200 / 4 micro-cartridge case; 300 / 2 micro-cartridge case; 300 / 4 micro-cartridge case.

[0107] Methods: CAM and CGM (containing approximately 1 mg of CAM) were prepared into drug-loaded magnetic microprojectiles using the weight loss method according to the methods of Examples 1 and 2, respectively. Each microprojectile was placed in a 10 mL centrifuge tube, and 2 mL of sodium acetate buffer (pH 5.0) was added. The microprojectiles were shaken at 37°C and 100 rpm for 24 h. 600 μL samples were taken at predetermined time points (1, 2, 4, 6, 12, and 24 h) and immediately replaced with an equal volume of acetate buffer. The supernatant was collected after centrifugation at 14,800 rpm for 10 min. The OD value at 490 nm was determined using a sulfuric acid colorimetric method. After subtracting the blank background, the OD value was substituted into the CAM standard curve to calculate the amount of CAM in the sample. The cumulative release curve of CAM from the drug-loaded magnetic microprojectiles was then plotted.

[0108] Results: With the improvement of solubility, the cumulative release rate of CAM in drug-loaded magnetic microprojectiles increased significantly. The design of the drug release hole at the bottom of the microprojectile shell cleverly ensures that the CAM in different microprojectiles can achieve long-term, stable and sustained release. Specifically, the CMMB (300 / 4 type CGM-loaded magnetic microprojectile) prepared in Example 2 showed excellent advantages in cumulative drug release performance, such as Figure 13 As shown in A, B, and C, they were therefore selected as the preferred drug-loaded magnetic microprojectiles for subsequent studies to optimize drug release.

[0109] 4. Retention time of drug-loaded magnetic microprojectiles in mice stomach

[0110] Materials: CMMB prepared according to Example 2, magnet block (3800GS, 5 mm diameter, 3 mm height).

[0111] Methods: Mice were anesthetized with isoflurane and gavage-administered with 0.3 mL of 20% iohexol solution on an empty stomach. The mice were then placed under an X-ray machine (the iohexol allowed visualization of the stomach's shape and position). CMMBs were coated with glycerol and placed vertically in the mouse's throat. A gavage needle was used to gently push the microprojectiles into the mouse's stomach. A magnet (3800GS, 5 mm diameter, 3 mm height) was placed above the abdomen of mice in the magnetic guidance group (MG) at the stomach site to control the trajectory of the microprojectiles (secured with a 3M transparent dressing). Under a portable X-ray machine, the mice were dissected at predetermined time points (8, 12, 16, 20, and 24 hours) to observe the location of the microprojectiles in the gastrointestinal tract. Mice in the non-magnetic guidance group (NMG), which received no other manipulations after microprojectile instillation, served as a control group. The mice were deprived of food but not water during the detention period.

[0112] Results: The microbullets can be visualized by the built-in magnet under X-ray (black dots indicated by arrows). Placing an external magnet near the pylorus can accurately guide the clarithromycin-loaded magnetic microbullets to the vicinity of the pylorus. Figure 14 , indicating that CMMB's positioning function is good. Figure 15 As shown, as time goes by, when there is no external magnetic field guidance, CMMB can be discharged along the intestine under the action of gastrointestinal peristalsis, and the gastric retention time of CMMB is only 8 to 12 hours; when an external magnetic field guidance is applied, the retention time of CMMB in the stomach exceeds 24 hours, which proves that CMMB has excellent gastric retention performance, which is its advantage.

[0113] 5. Investigation of gastric tissue puncture performance of drug-loaded magnetic microprojectiles

[0114] Materials: CMMB prepared according to Example 2, external circular magnet block (3800GS, 5 mm diameter, 3 mm height).

[0115] Methods: CMMBs were injected into the stomachs of C57BL / 6J mice according to the method described in (4. Retention time of drug-loaded magnetic microprojectiles in the mouse stomach). An external circular magnet (3800GS, 5 mm diameter, 3 mm height) was fixed to the abdominal skin outside the mouse stomach to magnetically guide the CMMBs. To investigate whether the microneedles could quickly penetrate the gastric tissue, the external magnet was removed after only 10 minutes. Ten minutes and seven days after the external magnetic field was removed, the gastric tissues of the mice were dissected and stained with hematoxylin and eosin (H&E). The penetration depth of the microprojectile needle tip and the subsequent recovery of the gastric mucosa were observed under a microscope.

[0116] Results: H&E staining results showed that the microneedle at the tip of the microbullet successfully penetrated the gastric tissue to a depth of approximately 270 μm, which is approximately 1 / 3 of the length of the microneedle, confirming the accuracy and effectiveness of the microbullet design. On the 7th day after administration, the gastric tissue recovered well and the tissue structure was intact. Figure 16 More importantly, the microprojectiles can be excreted smoothly with feces after completing drug release. Figure 17 , without causing intestinal obstruction, indicating good oral safety. This characteristic is of great significance for the clinical application of drug-loaded magnetic microprojectiles, ensuring their safety and controllability during in vivo operation.

[0117] 6. Investigation of the directional behavior of the magnetic microprojectile tip under magnetic guidance

[0118] Materials: CMMB prepared according to Example 2, 3% agarose gel block, external magnet (3800GS, 5 mm in diameter, 3 mm in height).

[0119] Methods: Following dissection according to the procedures in (5. Investigation of Gastric Tissue Penetration Performance of Drug-Loaded Magnetic Microprojectiles), the location of the CMMB within the stomach and the direction of its needle tip were carefully observed. The magnetic microprojectile was removed using ceramic scissors and released. The process of the microprojectile being attracted and adhering to the gastric wall under the guidance of an external magnetic field was observed and recorded. An external magnet (3800GS, 5 mm diameter, 3 mm height) was placed beneath the gel. The microprojectile was suspended obliquely above the gel block using ceramic scissors, with the needle tip pointing upward. The trajectory of the magnetic microprojectile was observed after the ceramic scissors were released. Pinholes in the agarose gel were observed 5 minutes later.

[0120] Results: In the in vivo experiment, the magnetic microbullet was orally administered into the stomach and successfully located at the pyloric region under the precise guidance of the external magnetic field. The needle tip was perpendicular to the pyloric stomach wall. After releasing the microbullet, the microbullet could be vertically injected into the pylorus again. Figure 18 In vitro experiments further confirmed that under the action of magnetic guidance, the magnetic microbullet quickly flipped upward from the initial needle tip and accurately inserted vertically into the agar block. After the external magnetic field was removed, 8 microneedle holes were clearly visible on the agarose gel. Figure 18Figure B shows that the external magnetic field can effectively control the microneedle's angle of incidence and that the needle tip has good penetrating properties. Both the internal and external magnets of the magnetic microprojectile are neodymium iron boron polar magnets. This allows precise targeting of the microprojectile to the pylorus during drug delivery, simply by ensuring the direction of the external magnetic field's polarity, thereby achieving precise drug release.

[0121] 7. Pharmacodynamics of drug-loaded magnetic microprojectiles in the treatment of Helicobacter pylori infection

[0122] Materials: CMMB prepared according to Example 2; CAM suspension (3 mg / mL); CGM solution (CAM concentration 3 mg / mL).

[0123] Methods: Mice were gavaged with fresh bacterial suspension for 30 consecutive days to establish a Helicobacter pylori mouse model. The mice were divided into a healthy group (no H. pylori infection, Healthy), a model group (H. pylori infection, untreated, Model), a clarithromycin group (H. pylori infection, gavage with clarithromycin suspension, CAM), a clarithromycin grind mixture group (H. pylori infection, gavage with clarithromycin grind mixture solution, CGM), and a drug-loaded magnetic microprojectile group (H. pylori infection, gavage with one CMMB). After instillation into the mouse stomach, the CMMB was guided to the pylorus by an external magnet. The magnet was removed 36 hours later. All mice fasted for 6 hours before dosing and received egg white for 36 hours after dosing, after which they resumed their normal diet. Seven days later, the mice were sacrificed, and the entire stomach was removed and divided longitudinally into two equal sections. One section was fixed in 4% paraformaldehyde and used for H&E and silver staining (WS) to observe histopathological morphology and the distribution of H. pylori in the gastric tissue. The other section was used for determination of H. pylori content in the gastric tissue.

[0124] Results: After Helicobacter pylori infection, the gastric mucosal tissue of the mice in the model group showed obvious erosion, which was deep into the lamina propria, and there was interstitial inflammatory cell infiltration. Figure 19 Compared with the model group, the CAM group showed no obvious gastric mucosal erosion, but large exfoliated cells were observed in the gastric mucosal epithelium. Compared with the CAM group, the CMMB group showed a significant mucosal repair effect, with no difference from the healthy group, with neatly arranged gastric parietal cells and restored structural integrity of the gastric mucosal epithelium and lamina propria.

[0125] Helicobacter pylori usually colonizes in the gastric mucus layer. A large number of black rod-shaped Helicobacter pylori were observed in the gastric pits at the pylorus of the model group mice. After treatment with clarithromycin-loaded magnetic microprojectiles, the content of Helicobacter pylori in gastric tissue decreased significantly, and Helicobacter pylori was almost not observed in gastric tissue. Figure 20 qPCR quantitative results showed that the clearance rate of Helicobacter pylori in the CMMB group was the highest, with the content of Helicobacter pylori in the stomach being 10 0.69 CFU / mg, significantly lower than that of the model group (106.06 CFU / mg) and CAM group (10 4.10 CFU / mg) and CGM group (10 3.30 CFU / mg), the difference was statistically significant (P<0.05), see Figure 21 , it is confirmed that CMMB has the ability to eradicate Helicobacter pylori in the body with a single oral dose, can reduce gastric damage, promote gastric mucosal repair, and has a positive effect on the treatment of gastric diseases such as chronic gastritis or ulcers caused by Helicobacter pylori.

[0126] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0127] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A gastric retention drug-loaded magnetic microprojectile, characterized in that: The device comprises a micro-cartridge, a magnet block and a drug; the main body of the micro-cartridge is a hollow cylindrical structure, the bottom of the cylinder is a closed thin sheet with small holes passing through the sheet, and the top ring of the hollow cylindrical structure is evenly distributed with microneedles with needle tips pointing upwards; The cavity portion of the hollow cylindrical structure is loaded with the medicine; the magnet block is horizontally placed on the medicine; The gastric-retention drug-loaded magnetic microprojectiles are prepared by a light-curing 3D printing method; The photocurable 3D printing method specifically comprises: preparing the micro-bullet shell by curing the printing solution from the material tank of the molding device layer by layer onto the printer platform according to the model parameters of the micro-bullet shell designed by the computer; The hollow cylindrical structure of the microcartridge is loaded with drugs. The drugs are filled into the microcartridge through the opening at the top of the microcartridge. After the drugs are filled into the microcartridge, a magnet block is placed horizontally above the drugs. The microcartridge 3D printing solution is used as a bonding material and dripped into the gap between the magnet block and the inner wall of the hollow cylinder of the microcartridge. The drug is quickly placed under a 405 nm laser light source for irradiation and curing, and the drugs and magnet block are encapsulated into the microcartridge to form a complete drug-loaded magnetic microcartridge.

2. The gastric-retaining drug-loaded magnetic microprojectile according to claim 1, characterized in that: The length of the micro-cartridge shell is selected from 0.2 cm to 2.5 cm; the inner diameter of the micro-cartridge shell is selected from 0.1 cm to 1 cm; the outer diameter of the micro-cartridge shell is selected from 0.12 cm to 1.02 cm; The thickness of the sheet is 0.05 mm to 0.1 mm; The number of the through holes is selected from 1 to 4, and the diameter of the through holes is 0.1 mm to 0.5 mm; The shape of the microneedles is selected from conical, cylindrical, triangular or quadrangular, and the number is selected from 3 to 15; The drug is selected from any one or a combination of clarithromycin, amoxicillin, tetracycline, metronidazole, rifamycin, furazolidone, levofloxacin, and ciprofloxacin.

3. The gastric-retaining drug-loaded magnetic microprojectile according to claim 2, characterized in that: The drug is selected from any one or a combination of clarithromycin, amoxicillin, and levofloxacin.

4. The gastric-retaining drug-loaded magnetic microprojectile according to claim 3, characterized in that: The length of the micro-bullet shell is selected from 0.2 cm to 1 cm; The inner diameter of the micro-bullet shell is selected from 0.1 cm to 0.6 cm; The outer diameter of the micro-bullet shell is selected from 0.12 cm to 0.62 cm; The microneedle is in the form of a tapered microneedle; the height of the tapered microneedle is selected from 0.2 mm to 1.5 mm; the bottom circular diameter of the tapered microneedle is selected from 0.2 mm to 3 mm; The drugs clarithromycin and 2-O-α-D-glucopyranosyl-L-ascorbic acid are uniformly mixed at a mass ratio of 2.2:1 and ground for 30 minutes to obtain a ground mixture of clarithromycin and 2-O-α-D-glucopyranosyl-L-ascorbic acid.

5. The gastric-retaining drug-loaded magnetic microprojectile according to claim 4, characterized in that: The printing solution is selected from acrylic acid, methyl acrylate, polypropylene fumarate, polyethylene glycol diacrylate, N-vinyl pyrrolidone, and silicone.

6. The gastric-retaining drug-loaded magnetic microprojectile according to claim 5, characterized in that: The printing solution is selected from any one of DentalSG, Dental LT Clear V2 resin, BioMed Clear resin, and BioMed Amber resin.

7. Use of the gastric-retaining drug-loaded magnetic microprojectile according to any one of claims 1 to 6 in the preparation of drugs or diagnostic and therapeutic equipment.

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