8-hydroxyquinoline iron-loaded cs-tpp nanocapsules, and preparation method and application thereof

Abstract

The application relates to the field of nanomaterial preparation, and discloses a CS-TPP nanocapsule loaded with 8-hydroxyquinoline iron, which is a chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron nanocapsule, wherein, in the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron nanocapsule, 8-hydroxyquinoline iron is coated by chitosan to form a microcapsule structure, the microcapsule structure can slowly release the 8-hydroxyquinoline iron coated in the inside, and the microcapsule is in the shape of a hexagonal prism; a preparation method thereof; and application of the nanocapsule in the field of preparing products for treating iron deficiency anemia. The application realizes nanocoating of FeQ, the hexagonal prism microcapsule structure constructed by CS-TPP can realize slow release of FeQ, prolongs the action time, and reduces biological toxicity; meanwhile, the microcapsule structure has high thermal stability, and can prolong the storage period of FeQ.

Description

Technical Field

[0001] This invention relates to the field of nanomaterial preparation, specifically to a CS-TPP nanocapsule loaded with 8-hydroxyquinoline iron, its preparation method, and its application. Background Technology

[0002] Iron is an essential trace element for animal life, participating in physiological activities such as red blood cell production, energy metabolism, and DNA repair. Prolonged iron deficiency leads to iron-deficiency anemia, manifesting 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 is as high as 52% in children, approximately 10% in adult males, and over 20% in adult females.

[0003] Although iron is primarily utilized by the body through the circulatory system, trace amounts are still lost daily through the natural shedding of intestinal mucosal cells, the stratum corneum of the skin, and hair. Women, especially those menstruating, pregnant, and breastfeeding, have increased iron requirements due to physiological factors such as menstrual blood loss, fetal development, and milk production, and therefore need to pay more attention to iron supplementation.

[0004] FeQ is a six-coordinated iron-8-hydroxyquinoline compound (8-hydroxyquinoline iron) synthesized by coordinating 8-hydroxyquinoline with FeCl3. 8-hydroxyquinoline is an important intermediate in the synthesis of drugs such as hydroxychloroquine, chloroiodoquinoline, and diiodoquinoline. Theoretically, FeQ has a good free iron delivery effect, which can deliver free iron into cells and 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 doses of FeQ act too quickly in vivo, resulting in a short retention time and poor persistence; (2) High concentrations of FeQ have certain biological toxicity; (3) It has a special taste, namely a rusty taste, which is not palatable; (4) It has a short shelf life.

[0005] Therefore, how to provide an iron supplement that is highly palatable and can be delivered in a slow-release manner has become a concern for those in the existing technical field. Summary of the Invention

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

[0007] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution:

[0008] This invention provides a CS-TPP nanocapsule loaded with 8-hydroxyquinoline iron, wherein the nanocapsule is a chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsule;

[0009] In the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules, 8-hydroxyquinoline iron is encapsulated by chitosan to form a microcapsule structure. The microcapsule structure can release the 8-hydroxyquinoline iron encapsulated inside it in a hexagonal prism shape.

[0010] As a preferred embodiment of the present invention, the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules have a particle size of 800-2400 nm.

[0011] The average particle size of the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules is 1397.0±259.7 nm.

[0012] This invention provides the application of CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron in the preparation of products for treating iron deficiency anemia.

[0013] As a preferred embodiment of the present invention, the product comprises a drug containing the CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron.

[0014] As a preferred embodiment of the present invention, it includes processed food containing the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules.

[0015] This invention also provides a method for preparing CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron, comprising the following steps:

[0016] S100. FeCl3 and 8-hydroxyquinoline are added to dimethyl sulfoxide and dissolved to obtain a mixed solution. The mixed solution is filtered using a filter membrane and dried at 60°C to obtain FeQ powder.

[0017] S200. Chitosan is added to an acetic acid solution to dissolve it, thereby obtaining a chitosan-acetic acid solution. The pH of the chitosan-acetic acid solution is adjusted to 4.5 using 1 mol / L NaOH. The chitosan-acetic acid solution is then sonicated, and Tween-80 is added. The solution is stirred for the first time to obtain a homogeneous solution.

[0018] S300. The 8-hydroxyquinoline iron powder is added to the homogeneous solution and stirred for a second time to obtain a CS-FeQ solution. Sodium tripolyphosphate solution is added dropwise to the CS-FeQ solution and stirred for a third time to obtain an emulsion. The emulsion is a suspension of hydroxyquinoline iron microcapsules.

[0019] S400. The suspension of the hydroxyquinoline iron microcapsules is subjected to low-temperature ultracentrifugation, the lower precipitate is taken out, suspended in double-distilled water, and dried to obtain the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules.

[0020] In a preferred embodiment of the present invention, in step S200, the chitosan-acetic acid solution is prepared as follows:

[0021] Chitosan powder was added to distilled water and a 1% acetic acid solution, and stirred on a magnetic stirrer for 6 hours to obtain a clear solution. The solution was then filtered through a 0.45 μM microporous membrane to obtain a chitosan-acetic acid solution.

[0022] The concentration of the chitosan-acetic acid solution is 1.0 mg / mL.

[0023] In a preferred embodiment of the present invention, in S100, the molar ratio of FeCl3 to 8-hydroxyquinoline is 1:2;

[0024] In S200, the mass fraction of Tween-80 is 1% of the homogeneous solution.

[0025] In a preferred embodiment of the present invention, in S300, the mass ratio of 8-hydroxyquinoline iron to chitosan in the CS-FeQ solution is 0.08-0.1:1;

[0026] The concentration of the sodium tripolyphosphate solution is 1.5 mg / mL, and the dropping rate is 2 drops / second;

[0027] The mass ratio of sodium tripolyphosphate to chitosan is 1:3-6.

[0028] 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;

[0029] In the oven, the drying temperature is 80°C and the drying time is 6 hours.

[0030] In a preferred embodiment of the present invention, the ultrasonic treatment temperature is 25°C, the power is 100W, and the treatment time is 10min;

[0031] The temperature of the first stirring was 60℃, and the stirring time was 30 minutes.

[0032] The temperature for the second stirring was 25°C, and the stirring time was 10 minutes.

[0033] The temperature for the third stirring was 25°C, and the stirring time was 20 minutes.

[0034] The low-temperature ultracentrifugation separation was carried out at a temperature of 4°C, a rotation speed of 12,000 rpm, and a centrifugation time of 30 min.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] The CS-TPP-FeQ nanocapsules constructed in this invention have a stable hexagonal prism structure, which enables sustained release of FeQ, allowing 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 action time of FeQ, realizing the application of FeQ in the field of preparing products for the treatment of iron deficiency anemia.

[0037] This invention encapsulates FeQ in a capsule structure. Compared to FeQ taken alone, 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 empty chitosan-sodium tripolyphosphate shells, which extends the shelf life of FeQ and makes it suitable for use as a drug or food additive for treating iron deficiency anemia.

[0038] This invention further provides a method for preparing chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules, which has high yield, strong operability, and is easy to scale up for subsequent production. Attached Figure Description

[0039] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0040] Figure 1 A schematic flowchart of the preparation method of CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron is provided for the present invention.

[0041] Figure 2 The present invention provides ultraviolet-visible spectra of FeQ, 8-hydroxyquinoline and FeCl3;

[0042] Figure 3 Fourier transform infrared spectral characterization results of CS-TPP-FeQ, CS-TPP, FeQ and 8-OH are provided for this invention;

[0043] Figure 4 X-ray diffraction patterns of CS-TPP-FeQ, CS-TPP, FeQ, and 8-HQ are provided for this invention;

[0044] Figure 5 This invention provides a statistical chart of CS-TPP-FeQ size distribution;

[0045] Figure 6 This invention provides a scanning electron microscope image of CS-TPP-FeQ.

[0046] Figure 7 Transmission electron microscope image of CS-TPP-FeQ is provided for this invention;

[0047] Figure 8 This invention provides statistical charts of CS-TPP-FeQ and CS-TPP thermogravimetric analysis.

[0048] Figure 9 This invention provides a statistical graph of serum iron concentration-time curves after SD rats were administered FeQ and FeCl3 by gavage;

[0049] Figure 10 To provide a comparative statistical chart of rat red blood cell count, red blood cell distribution width, hemoglobin, and mean hemoglobin concentration in Verification Example 5 for the present invention;

[0050] Figure 11 This invention provides a fluorescence staining image of reactive oxygen species in the rat jejunum from Example 5;

[0051] Figure 12 The present invention provides a statistical chart of reactive oxygen species in the rat jejunum in Example 5 for verification purposes. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] This invention provides a CS-TPP nanocapsule loaded with 8-hydroxyquinoline iron. This nanocapsule is a chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsule, which is formed by cross-linking 8-hydroxyquinoline iron, chitosan, and sodium tripolyphosphate.

[0054] The chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules (CS-TPP-FeQ) disclosed in this invention encapsulate 8-hydroxyquinoline iron within a chitosan-sodium tripolyphosphate structure. Chitosan (CS) is a non-toxic, biodegradable, and biocompatible nanoparticle shell material. Chitosan-sodium tripolyphosphate (CS-TPP) can partially crosslink 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 the hexagonal prism constructed by CS-TPP can also achieve sustained release of 8-hydroxyquinoline iron, prolonging the duration of action. The microcapsule structure has high thermal stability, which can extend the shelf life of 8-hydroxyquinoline iron, providing a feasible approach for the stable storage of 8-hydroxyquinoline iron.

[0055] The body's tolerance to iron supplements has certain limits. Although 8-hydroxyquinoline iron has high iron supplementation efficiency, its release rate is rapid and its duration of action is short. However, by encapsulating 8-hydroxyquinoline iron into microcapsules, its release rate is effectively controlled, and it possesses sustained release characteristics. This allows 8-hydroxyquinoline iron to exert its effects at concentrations below the cellular tolerance threshold for an extended period, even at higher doses. This not only retains the high efficiency of 8-hydroxyquinoline iron supplementation but also significantly prolongs its duration of action, thus enabling its use as a novel and highly effective iron supplement.

[0056] This chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsule has a particle size of 800-2400nm and an average particle size of 1397.0±259.7nm. It is suitable for use as a medicine or as a food additive in iron-related foods. It can be used as a new treatment product for iron deficiency diseases, providing treatment or adjunctive treatment and prevention.

[0057] This invention further discloses a method for preparing CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron, such as... Figure 1 As shown, it includes the following steps:

[0058] Step 1, Preparation of 8-hydroxyquinoline iron: FeCl3 and 8-hydroxyquinoline were added to dimethyl sulfoxide and dissolved to obtain a mixed solution. The mixed solution was filtered through a 0.22 μM filter membrane and dried at 60 °C to obtain FeQ powder.

[0059] Step 2, Chitosan Modification: Chitosan is added to an acetic acid solution to dissolve it, obtaining a CS-acetic acid solution. The pH of the CS-acetic acid solution is adjusted to 4.5 using 1 mol / L NaOH. The CS-acetic acid solution is then sonicated, and Tween-80 is added. After the first stirring, a homogeneous solution is obtained.

[0060] Step 3: Add the 8-hydroxyquinoline iron powder to the homogeneous solution and stir for a second time to obtain a CS-FeQ solution. Add sodium tripolyphosphate solution dropwise to the CS-FeQ solution and stir for a third time until an emulsion is obtained. The emulsion is a suspension of hydroxyquinoline iron microcapsules.

[0061] Step 4: The suspension of the hydroxyquinoline iron microcapsules is subjected to low-temperature ultracentrifugation, the lower precipitate is taken out, suspended in double-distilled water, and dried to obtain the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules.

[0062] In step 1, the amounts of FeCl3 and 8-hydroxyquinoline can be selected within any range. In a preferred embodiment, the molar ratio of FeCl3 to 8-hydroxyquinoline is 1:2.

[0063] In step 2, the CS-acetic acid solution is prepared as follows:

[0064] Chitosan powder was added to distilled water and 1% acetic acid solution, and stirred on a magnetic stirrer for 6 hours to obtain a clear solution. The solution was then filtered through a 0.45 μM microporous membrane to obtain a CS-acetic acid solution.

[0065] The concentration of the CS-acetic acid solution is 1.0 mg / mL.

[0066] The concentration of the acetic acid solution can be selected in a wide range, preferably 1.0% (v / v).

[0067] The Tween-80 can be selected from a wide range, and preferably, the mass of Tween-80 is 1% of the mass of the homogeneous solution.

[0068] The ultrasonic treatment time can be selected within a wide range. The ultrasonic treatment temperature is 25℃, the power is 100W, and the treatment time is 10min.

[0069] The temperature for the first stirring was 60℃, and the stirring time was 30 minutes.

[0070] In step 3, the mass ratio of FeQ to chitosan in the CS-FeQ solution is 0.08-0.1:1, that is, 1g of chitosan can coat 80-100mg of FeQ.

[0071] The concentration of the sodium tripolyphosphate solution is 1.5 mg / mL, the dropping rate is 2 drops / second, and the mass ratio of sodium tripolyphosphate to chitosan is 1:3-6.

[0072] To ensure more uniform mixing and thorough contact between FeQ and chitosan, the second stirring was performed at 25°C for 10 minutes. The third stirring was performed at 25°C for 20 minutes.

[0073] The time and speed of low-temperature ultracentrifugation can be selected within a wide range, but in order to maximize the yield of microcapsules, the temperature of the low-temperature ultracentrifugation is 4°C, the speed is 12000 rpm, and the centrifugation time is 30 min.

[0074] In step 4, the lower precipitate can be dried by freeze drying or oven drying. The freeze drying temperature is -20℃, and the oven drying temperature can be selected as 80℃, with a drying time of 6 hours.

[0075] There are various methods for preparing chitosan nanoparticles, including ionogel methods, covalent cross-linking methods, polymer compound methods, and self-assembly methods. Compared with other methods, ionogel methods have the advantages of mild reaction conditions and ease of industrialization. The preparation method disclosed in this invention is to prepare CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron using ionogel methods, which has high yield, strong operability, and facilitates subsequent large-scale production.

[0076] Meanwhile, this invention changes the steps for adding sodium tripolyphosphate. First, FeQ is reacted with modified chitosan to crosslink FeQ with the active groups on chitosan, and then crosslinked with sodium tripolyphosphate to achieve the coiling and 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.

[0077] The present invention further provides embodiments of FeQ and CS-TPP-FeQ, and characterizes CS-TPP-FeQ using methods such as ultraviolet spectroscopy (UV), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (DSC) and X-ray diffraction (XRD), while verifying the functional characteristics of CS-TPP-FeQ.

[0078] Example 1:

[0079] Preparation of FeQ:

[0080] Dissolve 1 mole of FeCl3 and 2 moles of 8-hydroxyquinoline in dimethyl sulfoxide, and filter the mixture through a 0.22 μM filter membrane.

[0081] The aforementioned reagents were purchased from Sinopharm Chemical Reagent Co., Ltd.

[0082] Preparation of microcapsules

[0083] Weigh 0.1 g of chitosan powder and add it to 98 mL of distilled water and 2 mL of 1% acetic acid solution. Stir on a magnetic stirrer for 6 h to obtain a clear solution. Filter the solution through a 0.45 μM microporous membrane to obtain a 1.0 mg / mL CS-acetic acid solution.

[0084] The pH of the CS-acetic acid solution was adjusted to 4.5 using 1 mol / L NaOH solution, and then sonicated at 25°C for 10 min with an ultrasonic power of 100 W. 1% Tween-80 was then added, and the solution was stirred at 60°C for 30 min to obtain a homogeneous solution.

[0085] The FeQ was added to a homogeneous solution to obtain a CS-FeQ solution. In the CS-FeQ solution, each 1g of CS contains 80-100mg of FeQ. The CS-FeQ solution was stirred at 25℃ for 10min, and then 1.5mg / mL of sodium tripolyphosphate was added dropwise at a rate of 2 drops / second. The stirring was continued for 20min until an emulsion was obtained. This emulsion is a suspension of 8-hydroxyquinoline iron microcapsules.

[0086] The 8-hydroxyquinoline iron microcapsule suspension was separated by low-temperature ultracentrifugation (4℃, 12000rpm, 30min), the lower precipitate was taken out and resuspended in double-distilled water, and dried in an oven at 80℃ for 6h to obtain chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules (CS-TPP-FeQ microcapsules).

[0087] The reagents for the microcapsules were purchased from Sinopharm Chemical Reagent Co., Ltd.

[0088] The CS-TPP-FeQ obtained in Example 1 is characterized below. The characterization data are compared with FeQ, FeCl3, CS-TPP, and 8-HQ. FeQ is taken from the FeQ prepared in Example 1.

[0089] The following provides several verification examples to characterize Example 1, FeQ group, FeCl3 group, CS-TPP group, and 8-HQ group.

[0090] Verification Example 1: The Structure of FeQ

[0091] (1) Iron forms a metal complex with 8-HQ.

[0092] The absorption peaks of FeQ, 8-hydroxyquinoline (8-OH) and FeCl3 were measured by ultraviolet-visible spectroscopy using a UV-Vis spectrophotometer (UV-2550, Shimadzu Corporation, Japan).

[0093] The results are as follows Figure 2As shown, 8-HQ and FeCl3 have no obvious absorption peaks in the 360-700 nm range, while FeQ shows two absorption peaks at 454 nm and 609 nm.

[0094] Conclusion: FeQ is not a mixture of FeCl3 and 8-HQ; 8-OH forms a metal complex with iron.

[0095] (2) Fe³⁺ replaces the hydrogen atom on the 8-OH hydroxyl group.

[0096] The structures of CS-TPP-FeQ microcapsules, CS-TPP, FeQ, and 8-OH were characterized using a Fourier transform infrared spectroscopy (Nicolet iS50, Thermo Scientific, USA). The results are as follows: Figure 3 As shown.

[0097] 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. Simultaneously, the stretching vibration peaks of C=N and C=O (1381-1508 cm⁻¹) also shifted, indicating that Fe³⁺ substituted for the hydrogen atom on the hydroxyl group of 8-OH.

[0098] Verification Example 2: Characterization of CS-TPP-FeQ

[0099] (1) Chemical structure of CS-TPP-FeQ

[0100] In the verification example provided, Figure 2 In the study, the Fourier transform infrared spectrum of CS-TPP-FeQ was similar to that of microcapsules without FeQ loading. The main transmittance variation was observed in the fingerprint region (1330-400 cm⁻¹), which was mainly related to steric hindrance and conjugation effect.

[0101] (2) Crystal structure of CS-TPP-FeQ

[0102] 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 GmbH, Germany) within the 2θ angle range of 5°–80°.

[0103] X-ray diffraction patterns of CS-TPP-FeQ, CS-TPP, FeQ, and 8-HQ are as follows: Figure 4 As shown.

[0104] As shown in the figure, the diffraction pattern of FeQ exhibits obvious diffraction peaks in the range of 2θ = 5-35°. Compared with the shell material (CS-TPP), CS-TPP-FeQ shows multiple characteristic peaks.

[0105] Conclusion: FeQ and CS-TPP are partially cross-linked, forming a compact structure.

[0106] (3) Size distribution of CS-TPP-FeQ

[0107] Dynamic light scattering (DLS) was used to measure the hydration diameter of the samples by preparing a suspension with double-distilled water. A Zetasizer (NANO-ZS90, Malvern, UK) was used for DLS detection, with an average of 12 scans performed at 25°C.

[0108] CS-TPP-FeQ size distribution statistics ( Figure 5 The results show that the particle size range of CS-TPP-FeQ is 800-2400 nm, and the average particle size is 1397.0 ± 259.7 nm.

[0109] (4) Surface morphology of CS-TPP-FeQ

[0110] The surface and cross-sectional morphology of CS-TPP-FeQ were observed using scanning electron microscopy (SEM, SU8010, HITACHI Corporation, Japan) and transmission electron microscopy (TEM, H7650, HITACHI Corporation, Japan) to verify the DLS results. SEM samples underwent gold sputtering, while TEM samples were dissolved in water and then dropped onto a copper mesh for observation. SEM and TEM provided direct visualization of the microcapsule surface morphology and internal structure.

[0111] Scanning electron microscope image from CS-TPP-FeQ ( Figure 6 The surface morphology of CS-TPP-FeQ can be clearly observed; the surface structure is complete, smooth, and dense. From the transmission electron microscope images of CS-TPP-FeQ (…), Figure 7 As can be seen, the microcapsules have a hexagonal prism structure.

[0112] The size obtained from the above morphological observation is basically consistent with the particle size measured by DLS.

[0113] Conclusion: The hexagonal prism constructed by CS-TPP successfully loaded FeQ and exhibited a certain sustained-release function.

[0114] Verification Example 3: Performance Analysis of CS-TPP-FeQ

[0115] CS-TPP-FeQ and CS-TPP thermogravimetric analysis

[0116] 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). The analysis conditions were constant nitrogen flow rate, heating rate of 10°C / min, and temperature range of 50-400°C.

[0117] Figure 8 The thermogravimetric analysis (TGA) graphs for CS-TPP-FeQ and CS-TPP show the thermal stability of the microcapsules. The thermal decomposition process of CS-TPP-FeQ and CS-TPP can be divided into three stages. The first stage (50-175℃) is related to moisture evaporation, and the mass loss of FeQ-loaded microcapsules is slower than that of the shell material. The second stage (175-300℃) corresponds to the breaking of glycosidic bonds between chitosan structural units. The third stage (300-400℃) is related to the decomposition of chitosan.

[0118] from Figure 8 As can be seen, FeQ exhibits good thermal stability after being embedded in microcapsules. Its stability is higher than that of CS-TPP itself between 50-175℃, providing a feasible approach for the stable storage of FeQ.

[0119] Verification Example 4: Pharmaceutical Performance Analysis of CS-TPP-FeQ in Example 1

[0120] Animal Experiments: Animal experiments were conducted in accordance with the guidelines of the Ethics Committee of Zhejiang University. After a 3-day pre-feeding period, all rats were fasted for 12 hours prior to the experiment. Twelve 10-week-old female SD rats (mean weight 283.50 ± 10.11 g) were randomly divided into three groups, each receiving 1 mL of physiological saline, FeCl3, or CS-TPP-FeQ (iron content 300 μg / mL) by gavage, respectively. The dosage design was based on the AIN-93G standard and the feed intake of 10-week-old SD rats, aiming to meet 30% of the rats' daily iron requirement. Following gavage, 200 μL of orbital venous blood was collected at 0, 15, 30, 45, 60, 75, 90, 120, 240, and 360 min. Serum was separated by centrifugation at 3000 rpm for 10 min at 4°C and stored at -80°C for pharmacokinetic analysis. Subsequently, based on the pharmacokinetic data, plasma from the SD rats was collected for routine blood tests.

[0121] Based on the above model, the pharmaceutical properties of CS-TPP-FeQ are compared with those of the comparative example FeCl3:

[0122] Pharmacokinetic analysis

[0123] The pharmacokinetic analysis method was as follows: serum iron concentration was determined using atomic absorption spectrometry, and plasma iron concentration-time curves were plotted. Pharmacokinetic parameters of iron were calculated using DAS2.0 software, directly obtaining the distribution and metabolic parameters of iron in SD rat plasma.

[0124] The statistical graph of serum iron concentration-time curves after gavage administration of FeQ and FeCl3 to SD rats is shown below. Figure 9 As shown in the figure, the pharmacokinetic curves of both the CS-TPP-FeQ and FeCl3 groups reached their peak values ​​at 30 min, but the serum iron concentration in the FeCl3 group decreased more rapidly after the peak. Pharmacokinetic curve fitting analysis indicated that FeCl3 conformed to a single-compartment model, while CS-TPP-FeQ conformed to a multi-compartment or sustained-release model, demonstrating slow release and long-term maintenance.

[0125] It is evident that at the same concentration, FeQ has a higher efficacy than FeCl3. This invention, by coating high doses of FeQ, enables the sustained release of high doses of FeQ into the body, thereby increasing the average residence time of FeQ and providing the body with iron continuously. This addresses the short residence time of FeQ and avoids the side effects caused by directly using large doses of FeQ, allowing FeQ to be used as a highly efficient iron supplement with a long residence time.

[0126] Example 5: Iron supplementation function and in vivo toxicity testing of CS-TPP-FeQ

[0127] ① Hematological parameter testing

[0128] Red blood cell count and hemoglobin levels are important indicators for assessing whether an organism is suffering from iron-deficiency anemia. A comparative statistical analysis was performed on the red blood cell count, red blood cell distribution width, hemoglobin, and mean corpuscular hemoglobin concentration in rats from the blank control group, the FeCl3 group, and the group treated in Example 1. The comparative statistical chart of red blood cell count, red blood cell distribution width, hemoglobin, and mean corpuscular hemoglobin concentration in rats is shown below. Figure 10 As shown in the figure, after FeQ supplementation, the number of red blood cells, hemoglobin, and mean hemoglobin concentration in rats were significantly increased. CS-TPP-FeQ can be used as a product in the treatment of iron deficiency anemia, for example, as an iron supplement or as a tablet.

[0129] ②Intestinal reactive oxygen species detection

[0130] Measurement of reactive oxygen species in tissues: Intestinal tissue from SD rats was frozen at -80°C, sectioned, stained with DHE, and washed three times with PBS. Subsequently, cell nuclei were stained with DAPI, and washed three more times with PBS. Finally, images were obtained under a fluorescence microscope.

[0131] The fluorescent staining image of reactive oxygen species in rat jejunum is shown below. Figure 11The statistical chart of reactive oxygen species in the rat jejunum is shown below. Figure 12 The results showed that iron supplementation could significantly inhibit the production of reactive oxygen species and reduce intestinal oxidative stress. Furthermore, the inhibitory effect of CS-TPP-FeQ was significantly better than that of FeCl3.

[0132] As demonstrated by the above verification examples, FeQ has excellent iron ion delivery capabilities and can be efficiently absorbed by the body, increasing the level of free iron in the body's cells. However, its effect is not sustained. After being coated to form CS-TPP-FeQ microcapsules, the microcapsules can achieve sustained release of FeQ, prolonging its duration of action and enabling it to act for a long time. In addition, it has high thermal stability, which is beneficial for long-term preservation.

[0133] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A CS-TPP nanocapsule loaded with 8-hydroxyquinoline iron, characterized in that, The nanocapsules are chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules; In the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsule, 8-hydroxyquinoline iron is encapsulated by chitosan to form a microcapsule structure. The microcapsule structure can release the 8-hydroxyquinoline iron encapsulated inside it. The microcapsule is hexagonal prism-shaped. The chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules have a particle size of 800-2400 nm.

2. The application of the CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron according to claim 1 in the preparation of drugs for treating iron deficiency anemia.

3. A method for preparing CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron as described in claim 1 or 2, characterized in that, Includes the following steps: S100. FeCl3 and 8-hydroxyquinoline are added to dimethyl sulfoxide and dissolved to obtain a mixed solution. The mixed solution is filtered using a filter membrane and dried at 60°C to obtain FeQ powder. S200. Chitosan is added to an acetic acid solution to dissolve it, thereby obtaining a chitosan-acetic acid solution. The pH of the chitosan-acetic acid solution is adjusted to 4.5 using 1 mol / L NaOH. The chitosan-acetic acid solution is then sonicated, and Tween-80 is added. The solution is stirred for the first time to obtain a homogeneous solution. S300. The 8-hydroxyquinoline iron powder is added to the homogeneous solution and stirred for a second time to obtain a CS-FeQ solution. Sodium tripolyphosphate solution is added dropwise to the CS-FeQ solution and stirred for a third time to obtain an emulsion. The emulsion is a suspension of hydroxyquinoline iron microcapsules. S400. The suspension of the hydroxyquinoline iron microcapsules is subjected to low-temperature ultracentrifugation, the lower precipitate is taken out, suspended in double-distilled water, and dried to obtain the chitosan-sodium tripolyphosphate-8-hydroxyquinoline iron microcapsules.

4. The method for preparing CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron according to claim 3, characterized in that, In step S200, the chitosan-acetic acid solution is prepared as follows: Chitosan powder was added to distilled water and a 1% acetic acid solution, and stirred on a magnetic stirrer for 6 hours to obtain a clear solution. The solution was then filtered through a 0.45 μM microporous membrane to obtain a chitosan-acetic acid solution. The concentration of the chitosan-acetic acid solution is 1.0 mg / mL.

5. The method for preparing CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron according to claim 3, characterized in that, In S100, the molar ratio of FeCl3 to 8-hydroxyquinoline is 1:2; In S200, the mass fraction of Tween-80 is 1% of the homogeneous solution.

6. The method for preparing CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron according to claim 3, characterized in that, In S300, the mass ratio of 8-hydroxyquinoline iron to 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 dropping rate is 2 drops / second; The mass ratio of sodium tripolyphosphate to chitosan is 1:3-6.

7. The method for preparing CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron according to claim 3, characterized in that, In S400, the drying is freeze-drying at -20°C or oven drying. In the oven, the drying temperature is 80°C and the drying time is 6 hours.

8. The method for preparing CS-TPP nanocapsules loaded with 8-hydroxyquinoline iron according to claim 3, characterized in that, The ultrasonic treatment was performed at a temperature of 25°C, a power of 100W, and a treatment time of 10 minutes. The temperature of the first stirring was 60℃, and the stirring time was 30 minutes. The temperature for the second stirring was 25°C, and the stirring time was 10 minutes. The temperature for the third stirring was 25°C, and the stirring time was 20 minutes. The low-temperature ultracentrifugation separation was carried out at a temperature of 4°C, a rotation speed of 12,000 rpm, and a centrifugation time of 30 min.

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