8-hydroxyquinoline iron-loaded CS-TPP nano microcapsule as well as preparation method and application thereof

Abstract

The invention relates to the field of nano material preparation, and discloses a CS-TPP nano microcapsule loaded with iron 8-hydroxyquinoline, the nano microcapsule is a chitosan-sodium tripolyphosphate-iron 8-hydroxyquinoline microcapsule, and in the chitosan-sodium tripolyphosphate-iron 8-hydroxyquinoline microcapsule, the chitosan-sodium tripolyphosphate-iron 8-hydroxyquinoline microcapsule is a chitosan-sodium tripolyphosphate-iron 8-hydroxyquinoline microcapsule, the chitosan-sodium tripolyphosphate-iron 8-hydroxyquinoline microcapsule is a chitosan-sodium tripolyphosphate-iron 8-hydroxyquinoline microcapsule. The 8-hydroxyquinoline iron is coated by chitosan to form a microcapsule structure, the microcapsule structure can slowly release the 8-hydroxyquinoline iron coated inside, and the microcapsule is in a hexagonal prism shape; as well as a preparation method thereof; the invention also discloses application of the composition in the field of preparation of products for treating iron-deficiency anemia. Nanometer coating of FeQ is achieved, a hexagonal prism-shaped microcapsule structure constructed by CS-TPP can achieve slow release of FeQ, action time is prolonged, and biotoxicity is reduced; meanwhile, the microcapsule structure has high thermal stability, and the storage life of FeQ can be prolonged.

Description

Technical Field

[0001] The present invention relates to the field of nanomaterial preparation, and in particular to 8-hydroxyquinoline iron-loaded CS-TPP nano-microcapsules and a preparation method and application thereof. Background Art

[0002] Iron is an essential trace element for animal life, involved in physiological processes such as red blood cell production, energy metabolism, and DNA repair. Prolonged iron deficiency can lead to iron-deficiency anemia, which manifests as fatigue, dizziness, and palpitations. Iron-deficiency anemia is the most common type of anemia worldwide. According to the World Health Organization, the incidence rate among children is as high as 52%, among male adults is approximately 10%, and among female adults, it exceeds 20%.

[0003] Although iron is primarily recycled through the body's circulatory system, trace amounts are lost daily through the natural shedding of intestinal mucosal cells, the stratum corneum of the skin, and hair. Women, especially those menstruating, pregnant, and lactating women, have an increased need for iron due to physiological factors such as menstrual blood loss, fetal development, and breast milk secretion, and therefore require increased iron supplementation.

[0004] FeQ is a hexacoordinated iron-8-hydroxyquinoline compound (8-hydroxyquinoline iron) synthesized by the coordination of 8-hydroxyquinoline and FeCl3. 8-Hydroxyquinoline is an important intermediate in the synthesis of drugs such as hydroxychloroquine, chloroiodoquinoline, and diiodoquinoline. In theory, FeQ has a good free iron delivery effect and can deliver free iron into cells to improve iron deficiency symptoms. However, in actual use, 8-hydroxyquinoline iron is mainly used as an industrial catalyst and is not used as an iron supplement. The reasons are as follows: (1) Low-dose FeQ acts too quickly in the body, resulting in a short retention time and poor sustainability; (2) High concentrations of FeQ have certain biological toxicity; (3) It has a special taste, namely rust, and poor palatability; (4) It has a short shelf life.

[0005] Therefore, how to provide an iron supplement with high palatability and sustained release delivery has become a problem of concern to people in the prior art. Summary of the Invention

[0006] The purpose of the present invention is to provide a CS-TPP nano-microcapsule loaded with 8-hydroxyquinoline iron and a preparation method and application thereof, so as to solve the above-mentioned technical problems existing in the prior art of FeQ.

[0007] In order to solve the above technical problems, the present invention specifically provides the following technical solutions: The present invention provides a CS-TPP nano-microcapsule loaded with 8-hydroxyquinoline iron, wherein the nano-microcapsule is a chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsule; In the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsule, 8-hydroxyquinoline iron is coated by chitosan to form a microcapsule structure. The microcapsule structure can slowly release the 8-hydroxyquinoline iron coated therein, and the microcapsule is in the shape of a hexagonal prism.

[0008] As a preferred embodiment of the present invention, the particle size of the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules is 800-2400 nm; The average particle size of the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules is 1397.0±259.7 nm.

[0009] The present invention provides application of CS-TPP nano-microcapsules loaded with 8-hydroxyquinoline iron in the field of preparing products for treating iron deficiency anemia.

[0010] As a preferred embodiment of the present invention, the product includes a drug containing the CS-TPP nano-microcapsules loaded with 8-hydroxyquinoline iron.

[0011] As a preferred embodiment of the present invention, the processed food contains the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules.

[0012] The present invention also provides a method for preparing CS-TPP nano-microcapsules loaded with 8-hydroxyquinoline iron, comprising the following steps: S100, adding FeCl3 and 8-hydroxyquinoline to dimethyl sulfoxide to obtain a mixed solution after dissolution, filtering the mixed solution through a filter membrane, and drying at 60° C. to obtain FeQ powder; S200, adding chitosan to an acetic acid solution for dissolution to obtain a chitosan-acetic acid solution, adjusting the pH of the chitosan-acetic acid solution to 4.5 with 1 mol / L NaOH, ultrasonically treating the chitosan-acetic acid solution, and then adding Tween-80 and stirring for the first time to obtain a uniform solution; S300, adding the 8-hydroxyquinoline iron powder to the uniform solution, stirring for a second time to obtain a CS-FeQ solution, adding a sodium tripolyphosphate solution dropwise to the CS-FeQ solution, stirring for a third time to obtain an emulsion, wherein the emulsion is a hydroxyquinoline iron microcapsule suspension; S400, subjecting the hydroxyquinoline iron microcapsule suspension to low-temperature ultracentrifugation, removing the lower precipitate, suspending it in double-distilled water, and drying it to obtain the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules.

[0013] As a preferred embodiment of the present invention, in S200, the chitosan-acetic acid solution is prepared as follows: Chitosan powder was added to distilled water and 1% acetic acid solution, stirred on a magnetic stirrer for 6 h to obtain a clear solution, which was filtered through a 0.45 μM microporous filter membrane to obtain a chitosan-acetic acid solution. The concentration of the chitosan-acetic acid solution is 1.0 mg / mL.

[0014] As a preferred embodiment of the present invention, in S100, the molar ratio of FeCl3 to 8-hydroxyquinoline is 1:2; In the S200, the mass fraction of the Tween-80 is 1% of the homogeneous solution.

[0015] As a preferred embodiment of the present invention, in the S300, the mass ratio of the 8-hydroxyquinoline iron to the chitosan in the CS-FeQ solution is 0.08-0.1:1; The concentration of the sodium tripolyphosphate solution is 1.5 mg / mL, and the dripping speed is 2 drops / second; The mass ratio of the sodium tripolyphosphate to the chitosan is 1:3-6.

[0016] As a preferred embodiment of the present invention, in S400, the drying is freeze-drying at -20°C or drying in an oven, preferably freeze-drying at -20°C; In the oven, the drying temperature is 80° C. and the drying time is 6 h.

[0017] As a preferred embodiment of the present invention, the temperature of the ultrasonic treatment is 25°C, the power is 100W, and the treatment time is 10 minutes; The first stirring temperature is 60°C and the stirring time is 30 minutes; The second stirring temperature is 25°C and the stirring time is 10 minutes; The third stirring temperature is 25°C and the stirring time is 20 minutes; The temperature of the low-temperature ultracentrifugation separation is 4° C., the rotation speed is 12000 rpm, and the centrifugation time is 30 min.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The CS-TPP-FeQ nanocapsules constructed by the present invention have a stable hexagonal prism structure and can achieve sustained release of FeQ, enabling it to be released at a low concentration for a long time. This not only retains the high iron supplementation efficiency of FeQ but also prolongs the duration of FeQ's action, thus realizing the application of FeQ in the preparation of products for treating iron deficiency anemia. The present invention encapsulates FeQ in a capsule structure. Compared with taking FeQ alone, the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules have a better taste. At the same time, the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules have a stable structure and higher thermal stability than FeQ and chitosan-sodium tripolyphosphate empty shells, extending the shelf life of FeQ, enabling it to be used as a drug or food additive for treating iron deficiency anemia. The present invention further provides a preparation method of chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules, which has high yield, strong operability and is convenient for subsequent large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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 the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other implementation drawings based on the provided drawings without inventive effort.

[0020] Figure 1 The present invention provides a schematic flow chart of a method for preparing CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron; Figure 2 The present invention provides ultraviolet-visible spectra of FeQ, 8-hydroxyquinoline and FeCl3; Figure 3 The present invention provides a graph showing the Fourier transform infrared spectroscopy characterization results of CS-TPP-FeQ, CS-TPP, FeQ and 8-OH; Figure 4 The present invention provides X-ray diffraction patterns of CS-TPP-FeQ, CS-TPP, FeQ and 8-HQ; Figure 5 Provides a statistical diagram of the size distribution of CS-TPP-FeQ for the present invention; Figure 6 The present invention provides a scanning electron microscope image of CS-TPP-FeQ; Figure 7 The present invention provides a transmission electron microscopy image of CS-TPP-FeQ; Figure 8 The present invention provides a statistical diagram of thermogravimetric analysis of CS-TPP-FeQ and CS-TPP; Figure 9 The present invention provides a statistical graph of serum iron concentration-time curve after SD rats were gavaged with FeQ and FeCl3; Figure 10Provided are comparative statistical graphs of rat red blood cell count, red blood cell distribution width, hemoglobin, and mean hemoglobin concentration in Verification Example 5 of the present invention; Figure 11 Provided is the reactive oxygen species fluorescence staining image of rat jejunum in Verification Example 5 of the present invention; Figure 12 The present invention provides a statistical diagram of active oxygen in rat jejunum in Verification Example 5. DETAILED DESCRIPTION

[0021] 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.

[0022] The invention provides a CS-TPP nano-microcapsule loaded with 8-hydroxyquinoline iron. The nano-microcapsule is a chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsule, which is formed by cross-linking 8-hydroxyquinoline iron, chitosan and sodium tripolyphosphate.

[0023] The chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules (CS-TPP-FeQ) disclosed in the present invention encapsulate 8-hydroxyquinoline iron through a chitosan-sodium tripolyphosphate structure. Chitosan (CS) is a non-toxic, biodegradable nanoparticle shell material with good biocompatibility. Chitosan-sodium tripolyphosphate (CS-TPP) can partially cross-link with 8-hydroxyquinoline iron to form a stable microcapsule structure. The microcapsule structure not only improves the taste of 8-hydroxyquinoline iron to a certain extent, but also the hexagonal prisms constructed by CS-TPP can achieve sustained release of 8-hydroxyquinoline iron and prolong the duration of action. The microcapsule structure has high thermal stability and can extend the shelf life of 8-hydroxyquinoline iron, providing a feasible approach for the stable storage of 8-hydroxyquinoline iron.

[0024] The body's tolerance to iron supplements has a certain limit. Although 8-hydroxyquinoline iron has a high iron supplement efficiency, its release rate is fast and its retention time is short. However, after 8-hydroxyquinoline iron is embedded in a microcapsule structure, its release rate is effectively controlled and has sustained release characteristics. Even at higher doses, 8-hydroxyquinoline iron can still exert its effect for a long time at a concentration below the cell tolerance threshold. This not only retains the advantages of 8-hydroxyquinoline iron's high iron supplementation efficiency, but also significantly prolongs its duration of action, making it suitable for use as a new type of highly effective iron supplement.

[0025] The chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules have a particle size of 800-2400 nm, with an average particle size of 1397.0±259.7 nm. They are suitable for use as a medicine or as a food additive in iron-supplementing foods. They can be used as a new therapeutic product for iron deficiency diseases, providing treatment or auxiliary treatment and prevention.

[0026] The present invention further discloses a method for preparing CS-TPP nano-microcapsules loaded with 8-hydroxyquinoline iron, such as Figure 1 As shown, the following steps are included: Step 1, preparation of 8-hydroxyquinoline iron: FeCl3 and 8-hydroxyquinoline were added to dimethyl sulfoxide, and dissolved to obtain a mixed solution, which was filtered through a 0.22 μM filter membrane and dried at 60° C. to obtain FeQ powder; Step 2, chitosan modification: chitosan was added to an acetic acid solution for dissolution to obtain a CS-acetic acid solution, the pH of the CS-acetic acid solution was adjusted to 4.5 with 1 mol / L NaOH, the CS-acetic acid solution was ultrasonically treated, and Tween-80 was added and stirred for the first time to obtain a homogeneous solution; Step 3, adding the 8-hydroxyquinoline iron powder to the uniform solution, stirring for a second time to obtain a CS-FeQ solution, adding sodium tripolyphosphate solution dropwise to the CS-FeQ solution, and stirring for a third time until an emulsion is obtained, wherein the emulsion is a hydroxyquinoline iron microcapsule suspension; Step 4: subjecting the hydroxyquinoline iron microcapsule suspension to low-temperature ultracentrifugation, removing the lower precipitate, suspending it in double-distilled water, and drying it to obtain the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules.

[0027] In step 1, the added amounts of the FeCl 3 and the 8-hydroxyquinoline can be selected within any range. In a preferred embodiment, the molar ratio of the FeCl 3 to the 8-hydroxyquinoline is 1:2.

[0028] In step 2, the CS-acetic acid solution is prepared as follows: Chitosan powder was added to distilled water and 1% acetic acid solution, and stirred on a magnetic stirrer for 6 h to obtain a clear solution, which was then filtered through a 0.45 μM microporous filter membrane to obtain a CS-acetic acid solution. The concentration of the CS-acetic acid solution was 1.0 mg / mL.

[0029] The concentration of the acetic acid solution can be selected within a wide range. Preferably, the concentration of the acetic acid solution is 1.0% (v / v).

[0030] The Tween-80 can be selected from a wide range. Preferably, the mass of Tween-80 is 1% of the mass of the homogeneous solution.

[0031] The ultrasonic treatment time can be selected within a wide range. The ultrasonic treatment temperature is 25° C., the power is 100 W, and the treatment time is 10 min.

[0032] The temperature of the first stirring was 60°C and the stirring time was 30 min.

[0033] In step 3, the mass ratio of FeQ to chitosan in the CS-FeQ solution is 0.08-0.1:1, that is, 80-100 mg of FeQ can be coated per 1 g of chitosan.

[0034] The concentration of the sodium tripolyphosphate solution is 1.5 mg / mL, the dripping speed is 2 drops / second, and the mass ratio of the sodium tripolyphosphate to chitosan is 1:3-6.

[0035] In order to stir more evenly and ensure that FeQ and chitosan are fully contacted, the second stirring temperature is 25°C and the stirring time is 10 minutes. The third stirring temperature is 25°C and the stirring time is 20 minutes.

[0036] The time and speed of low-temperature ultracentrifugation can be selected within a wide range. However, in order to maximize the yield of microcapsules, the temperature of the low-temperature ultracentrifugation is 4° C., the speed is 12,000 rpm, and the centrifugation time is 30 min.

[0037] In step 4, the lower precipitate can be dried by freeze drying or oven drying. The freeze drying temperature is -20°C, the oven drying temperature can be 80°C, and the drying time is 6 hours.

[0038] Chitosan nanoparticles can be prepared using a variety of methods, including ionomeric gelation, covalent crosslinking, polymer compounding, and self-assembly. Compared to these methods, the ionomeric gelation method offers mild reaction conditions and ease of industrialization. The present invention discloses a method for preparing 8-hydroxyquinoline iron-loaded CS-TPP nanocapsules using the ionomeric gelation method, resulting in high yields, strong operability, and ease of subsequent scale-up.

[0039] At the same time, the present invention changes the addition step of sodium tripolyphosphate. First, FeQ is reacted with modified chitosan to cross-link FeQ with the active groups on chitosan, and then cross-linked with sodium tripolyphosphate to achieve curling coating of FeQ, so as to maximize the coating of FeQ into the entire microcapsule structure, improve the coating efficiency, and make the structure more stable.

[0040] The present invention further provides examples of FeQ and CS-TPP-FeQ, and characterizes CS-TPP-FeQ using ultraviolet spectroscopy (UV), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (DSC), and X-ray diffraction (XRD), while verifying the functional properties of CS-TPP-FeQ.

[0041] Example 1: Preparation of FeQ: 1 mol of FeCl3 and 2 mol of 8-hydroxyquinoline were dissolved in dimethyl sulfoxide, and the mixed solution was filtered through a 0.22 μM filter membrane.

[0042] The above-mentioned related reagents were purchased from Sinopharm Chemical Reagent Co., Ltd.

[0043] Preparation of microcapsules Weigh 0.1 g of chitosan powder, add 98 mL of distilled water and 2 mL of 1% acetic acid solution, place on a magnetic stirrer and stir for 6 h to obtain a clear solution, which is then filtered through a 0.45 μM microporous filter membrane to obtain a 1.0 mg / mL CS-acetic acid solution; The pH of the CS-acetic acid solution was adjusted to 4.5 with 1 mol / L NaOH solution, and ultrasonic treatment was performed at 25°C for 10 min with an ultrasonic power of 100 W. Then, 1% mass fraction of Tween-80 was added; and the mixture was stirred at 60°C for 30 min to obtain a homogeneous solution.

[0044] The above FeQ was added to the homogeneous solution to obtain a CS-FeQ solution. In the CS-FeQ solution, 80-100 mg of FeQ was contained per 1 g of CS. The CS-FeQ solution was stirred at 25° C. for 10 minutes, and then 1.5 mg / mL sodium tripolyphosphate was added dropwise at a rate of 2 drops / second. The stirring was continued for 20 minutes until an emulsion was obtained. This emulsion is an 8-hydroxyquinoline iron microcapsule suspension. The 8-hydroxyquinoline iron microcapsule suspension was separated by low-temperature ultracentrifugation (4°C, 12000 rpm, 30 min), the lower precipitate was removed, suspended in double-distilled water, and dried in an oven at 80°C for 6 h to obtain chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules (CS-TPP-FeQ microcapsules).

[0045] The relevant reagents for microcapsules were purchased from Sinopharm Chemical Reagent Co., Ltd.

[0046] The CS-TPP-FeQ obtained in Example 1 is characterized below, wherein the characterization data are compared with FeQ, FeCl3, CS-TPP, and 8-HQ, wherein FeQ is obtained from the preparation of FeQ in Example 1.

[0047] The following provides multiple verification examples to characterize Example 1, FeQ group, FeCl3 group, CS-TPP group, and 8-HQ group.

[0048] Verification Example 1: Structure of FeQ (1) Iron and 8-HQ form a metal complex The absorption peaks of FeQ, 8-hydroxyquinoline (8-OH), and FeCl3 were measured by UV-visible spectroscopy using an UV-visible spectrophotometer (UV-2550, Shimadzu Corporation, Japan).

[0049] The results are as follows Figure 2 As shown, 8-HQ and FeCl3 have no obvious absorption peaks in the range of 360-700nm, while FeQ has two absorption peaks at 454nm and 609nm.

[0050] Conclusion: FeQ is not a mixture of FeCl3 and 8-HQ, and 8-OH forms a metal complex with iron.

[0051] (2) Fe³⁺ replaces the hydrogen atom on the 8-OH hydroxyl group The structures of CS-TPP-FeQ microcapsules, CS-TPP, FeQ and 8-OH were characterized using Fourier transform infrared spectrometer (Nicolet iS50, Thermo Scientific, USA). Figure 3 shown.

[0052] exist Figure 3 In the infrared spectra of FeQ and 8-OH, the absorption peaks of the ligand 8-OH at 3048 cm⁻¹ (υ(OH)) and 1286 cm⁻¹ (δ(OH)) changed compared to those of FeQ and 8-OH. At the same time, the stretching vibration peaks of C=N and C=O (1381-1508 cm⁻¹) also shifted, indicating that Fe³⁺ replaced the hydrogen atom on the hydroxyl group of 8-OH.

[0053] Verification Example 2: Characterization of CS-TPP-FeQ (1) Chemical structure of CS-TPP-FeQ In the verification example 1 provided, Figure 2 The Fourier transform infrared spectrum of CS-TPP-FeQ is similar to that of microcapsules without FeQ loading, and the main transmittance change is reflected in the fingerprint region (1330-400 cm⁻¹), which is mainly related to steric hindrance and conjugation effects.

[0054] (2) Crystal structure of CS-TPP-FeQ The crystal structures of CS-TPP-FeQ, CS-TPP, FeQ, and 8-HQ were determined using an X-ray diffractometer (XRD, Bruker D8 Advance, Bruker, Germany) in the 2θ angle range of 5°–80°.

[0055] The X-ray diffraction patterns of CS-TPP-FeQ, CS-TPP, FeQ and 8-HQ are as follows: Figure 4 shown.

[0056] As can be seen from the figure, the diffraction pattern of FeQ shows obvious diffraction peaks in the range of 2θ = 5-35°. Compared with the shell material (CS-TPP), CS-TPP-FeQ shows multiple characteristic peaks.

[0057] Conclusion: FeQ and CS-TPP are partially cross-linked to form a compact structure.

[0058] (3) Size distribution of CS-TPP-FeQ The samples were suspended in double-distilled water and their hydrated diameters were determined using dynamic light scattering (DLS). Dynamic light scattering was performed using a Zetasizer (NANO-ZS90, Malvern, UK) with an average of 12 scans at 25°C.

[0059] CS-TPP-FeQ size distribution statistics ( Figure 5 ) showed that the particle size range of CS-TPP-FeQ was 800-2400 nm, with an average particle size of 1397.0 ± 259.7 nm.

[0060] (4) Surface morphology of CS-TPP-FeQ Scanning electron microscopy (SEM, SU8010, HITACHI, Japan) and transmission electron microscopy (TEM, H7650, HITACHI, Japan) were used to observe the surface and cross-sectional morphology of the CS-TPP-FeQ microcapsules to verify the DLS results. SEM samples were gold-sputtered, while TEM samples were dissolved in water and then dropped onto a copper grid for observation. Both SEM and TEM techniques visually observed the surface morphology and internal structure of the microcapsules.

[0061] From the scanning electron microscopy image of CS-TPP-FeQ ( Figure 6 ) The surface morphology of CS-TPP-FeQ can be clearly observed, and the surface structure is complete, smooth and dense. From the transmission electron microscopy image of CS-TPP-FeQ ( Figure 7 ) It can be seen that the microcapsules have a hexagonal prism structure.

[0062] The size obtained from the above morphological observation is basically consistent with the particle size measured by DLS.

[0063] Conclusion: The hexagonal prisms constructed by CS-TPP were successfully loaded with FeQ and had a certain sustained-release function.

[0064] Verification Example 3: CS-TPP-FeQ Performance Analysis Thermogravimetric analysis of CS-TPP-FeQ and CS-TPP Thermogravimetric analysis of CS-TPP-FeQ and CS-TPP was performed using a differential thermal-thermogravimetric analyzer (DTA-TG, Mettler Toledo STARe System TGA2, Mettler Toledo, Switzerland) under the following conditions: a constant nitrogen flow rate, a heating rate of 10°C / min, and a temperature range of 50–400°C.

[0065] Figure 8 Thermogravimetric analysis of CS-TPP-FeQ and CS-TPP shows the thermal stability of the microcapsules. The thermal decomposition of CS-TPP-FeQ and CS-TPP can be divided into three stages. The first stage (50-175°C) is associated with water evaporation, with the FeQ-loaded microcapsules losing mass more slowly than the shell material. The second stage (175-300°C) corresponds to the cleavage of glycosidic bonds between chitosan structural units. The third stage (300-400°C) is associated with the decomposition of chitosan.

[0066] from Figure 8 It can be seen that after FeQ is embedded in the microcapsules, it has good thermal stability. Its stability between 50-175°C is higher than that of CS-TPP itself, which provides a feasible idea for the stable storage of FeQ.

[0067] Verification Example 4: Pharmaceutical Performance Analysis of CS-TPP-FeQ in Example 1 Animal experimentation: Animal experiments were conducted in accordance with the guidelines of the Zhejiang University Ethics Committee. After a 3-day pre-feeding period, all rats were fasted for 12 hours before the experiment. Twelve 10-week-old female Sprague-Dawley rats (mean weight, 283.50 ± 10.11 g) were randomly divided into three groups and gavaged with 1 mL of normal saline, FeCl₃, or CS-TPP-FeQ (iron content, 300 μg / mL) per group. The doses were designed based on the AIN-93G standard and the food intake of 10-week-old Sprague-Dawley rats, and were expected to meet 30% of the rats' daily iron requirement. After gavage, 200 μL of orbital venous blood was collected at 0, 15, 30, 45, 60, 75, 90, 120, 240, and 360 minutes. Serum was separated by centrifugation at 3000 rpm for 10 minutes at 4°C and stored at −80°C for pharmacokinetic analysis. Subsequently, based on the pharmacokinetic data, plasma was collected from the Sprague-Dawley rats for routine hematological analysis.

[0068] According to the above model, the pharmaceutical properties of CS-TPP-FeQ were compared with the comparative example FeCl3: Pharmacokinetic analysis Pharmacokinetic analysis methods included measuring serum iron concentration using atomic absorption spectrometry, plotting plasma iron concentration-time curves, and calculating iron pharmacokinetic parameters using DAS2.0 software to directly obtain iron distribution and metabolic parameters in SD rat plasma.

[0069] The statistical graph of serum iron concentration-time curve after oral administration of FeQ and FeCl3 in SD rats is shown in the figure. Figure 9 The pharmacokinetic curves for both the CS-TPP-FeQ and FeCl3 groups reached peak values ​​at 30 minutes, but serum iron concentrations in the FeCl3 group declined more rapidly after peaking. Pharmacokinetic curve fitting analysis showed that FeCl3 conformed to a single-compartment model, while CS-TPP-FeQ conformed to a multicompartment or sustained-release model, demonstrating slow release and long-term maintenance.

[0070] It can be seen that at the same concentration, the efficacy of FeQ is higher than that of FeCl3. The present invention encapsulates a high dose of FeQ so that the high dose of FeQ can be slowly released in the body, thereby increasing the average residence time of FeQ, thereby continuously providing iron to the body, resolving the defect of its short residence time, avoiding the side effects caused by the direct use of large doses of FeQ, and enabling FeQ to be used as a high-efficiency and long-residence iron supplement.

[0071] Example 5: Iron supplementation function of CS-TPP-FeQ and in vivo toxicity testing ①Hematological parameter detection The red blood cell count and hemoglobin index are important criteria for measuring whether the body is in iron deficiency anemia. The red blood cell count, red blood cell distribution width, hemoglobin and mean hemoglobin concentration of the rats in the blank control group, the FeCl3 group and the Example 1 group were compared and statistically analyzed. The comparative statistical graph of the red blood cell count, red blood cell distribution width, hemoglobin and mean hemoglobin concentration of the rats is shown in FIG. Figure 10 As can be seen from the figure, after supplementing with FeQ, the rats' red blood cell count, hemoglobin, and average hemoglobin concentration all increased significantly. CS-TPP-FeQ can be used as a product to treat iron deficiency anemia, for example, directly as an iron supplement or produced as tablets.

[0072] ②Intestinal reactive oxygen species detection Measurement of tissue reactive oxygen species: SD rat intestinal tissue was frozen at -80°C, sectioned, stained with DHE, and washed three times with PBS. Subsequently, nuclei were stained with DAPI and washed again three times with PBS. Finally, images were obtained under a fluorescence microscope.

[0073] Figure 2. Fluorescence staining of active oxygen species in rat jejunum. Figure 11 , the statistical diagram of active oxygen in rat jejunum is shown in Figure 12 The results showed that iron supplementation can significantly inhibit the production of reactive oxygen species and reduce intestinal oxidative stress. At the same time, the inhibitory effect of CS-TPP-FeQ is significantly better than that of FeCl3.

[0074] The above verification examples show that FeQ has excellent iron ion delivery ability and can be efficiently absorbed by the body to increase the level of free iron in the body's cells. However, its own effect is not long-lasting. After being coated to form CS-TPP-FeQ microcapsules, the microcapsules can achieve sustained release of FeQ, extending its duration of action, thereby enabling it to act for a long time. It also has high thermal stability, which is conducive to long-term storage.

[0075] The above embodiments are merely exemplary embodiments of the present application and are not intended to limit the scope of the present application. The scope of protection of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and scope of protection of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the scope of protection of the present application.

Claims

1. A CS-TPP nanocapsule loaded with 8-hydroxyquinoline iron, characterized in that: The nano-microcapsules are chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules; In the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsule, 8-hydroxyquinoline iron is coated by chitosan to form a microcapsule structure. The microcapsule structure can slowly release the 8-hydroxyquinoline iron coated therein, and the microcapsule is in the shape of a hexagonal prism.

2. The CS-TPP nanocapsule loaded with 8-hydroxyquinoline iron according to claim 1, characterized in that: The particle size of the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsule is 800-2400 nm.

3. Use of the CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron according to claim 1 or 2 in the preparation of products for treating iron deficiency anemia.

4. A use according to claim 3, characterized in that The product comprises a medicine containing the CS-TPP nano-microcapsule loaded with 8-hydroxyquinoline iron.

5. A method for preparing the CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron according to any one of claims 1 to 4, characterized in that: The steps include: S100, adding FeCl3 and 8-hydroxyquinoline to dimethyl sulfoxide to obtain a mixed solution after dissolution, filtering the mixed solution with a filter membrane, and drying at 60° C. to obtain FeQ powder; S200, adding chitosan to an acetic acid solution for dissolution to obtain a chitosan-acetic acid solution, adjusting the pH of the chitosan-acetic acid solution to 4.5 with 1 mol / L NaOH, ultrasonically treating the chitosan-acetic acid solution, and then adding Tween-80 and stirring for the first time to obtain a uniform solution; S300, adding the 8-hydroxyquinoline iron powder to the uniform solution, stirring for a second time to obtain a CS-FeQ solution, adding a sodium tripolyphosphate solution dropwise to the CS-FeQ solution, stirring for a third time to obtain an emulsion, wherein the emulsion is a hydroxyquinoline iron microcapsule suspension; S400, subjecting the hydroxyquinoline iron microcapsule suspension to low-temperature ultracentrifugation, removing the lower precipitate, suspending it in double-distilled water, and drying it to obtain the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules.

6. The method for preparing CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron according to claim 5, characterized in that: In the S200, the chitosan-acetic acid solution is prepared as follows: Chitosan powder was added to distilled water and 1% acetic acid solution, stirred on a magnetic stirrer for 6 h to obtain a clear solution, which was filtered through a 0.45 μM microporous filter membrane to obtain a chitosan-acetic acid solution. The concentration of the chitosan-acetic acid solution is 1.0 mg / mL.

7. The method for preparing CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron according to claim 5, characterized in that: In the S100, the molar ratio of the FeCl3 to the 8-hydroxyquinoline is 1:2; In the S200, the mass fraction of the Tween-80 is 1% of the homogeneous solution.

8. The method for preparing CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron according to claim 5, characterized in that: In the S300, the mass ratio of the 8-hydroxyquinoline iron to the chitosan in the CS-FeQ solution is 0.08-0.1:1; The concentration of the sodium tripolyphosphate solution is 1.5 mg / mL, and the dripping speed is 2 drops / second; The mass ratio of the sodium tripolyphosphate to the chitosan is 1:3-6.

9. The method for preparing CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron according to claim 5, characterized in that: In the step S400, the drying is freeze-drying at -20°C or drying in an oven; In the oven, the drying temperature is 80° C. and the drying time is 6 h.

10. The method for preparing CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron according to claim 5, characterized in that: The ultrasonic treatment temperature is 25°C, the power is 100W, and the treatment time is 10min; The first stirring temperature is 60°C and the stirring time is 30 minutes; The second stirring temperature is 25°C and the stirring time is 10 minutes; The third stirring temperature is 25°C and the stirring time is 20 minutes; The temperature of the low-temperature ultracentrifugation separation is 4° C., the rotation speed is 12000 rpm, and the centrifugation time is 30 min.

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