A method for preparing a microneedle

Abstract

The application discloses a kind of soluble microneedle of triplex nano self-assembly and its preparation method and application.The microneedle tip is mixed with nanometer particle by hyaluronic acid, and the base is made of polyvinylpyrrolidone;The nanometer particle is formed by supermolecular self-assembly by ivy alkaloid derivative molecule, doxorubicin hydrochloride and irinotecan.The preparation method is as follows: ivy alkaloid derivative and irinotecan are dissolved in dichloromethane, doxorubicin hydrochloride is dissolved in methanol, and the mixture is the oil phase;With sodium cholate aqueous solution as water phase, nanoemulsion is prepared by two-step ultrasonic emulsification, and the solvent is dried to obtain.The microneedle is prepared by PDMS template centrifugal casting method.The application delivers the three drugs to breast cancer locally through microneedle, ivy alkaloid derivative reverses multidrug resistance, irinotecan induces copper death, and doxorubicin plays a chemotherapy role, synergistic effect of the three, and local administration reduces systemic toxicity, to provide a new scheme for drug-resistant breast cancer treatment.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical preparations, and specifically relates to a method for preparing microneedles. Background Technology

[0002] Breast cancer is a common malignant tumor that seriously threatens women's health. Chemotherapy plays a central role in the comprehensive treatment of breast cancer. Doxorubicin hydrochloride, as a broad-spectrum anthracycline antitumor drug, exerts its cytotoxic effects through mechanisms such as intercalation into DNA base pairs, inhibition of topoisomerase II activity, and generation of oxygen free radicals, making it a first-line drug for breast cancer chemotherapy. However, the formation of multidrug resistance (MDR) in tumors severely restricts the clinical efficacy of doxorubicin and is a major cause of chemotherapy failure and poor prognosis in breast cancer patients.

[0003] The mechanisms of multidrug resistance are extremely complex, involving the synergistic effects of multiple factors. One of the most classic pathways is the overexpression of P-glycoprotein (P-gp) on the tumor cell membrane. Encoded by the MDR1 gene, P-gp belongs to the ATP-binding cassette transporter superfamily and is essentially an ATP-dependent drug efflux pump. It actively pumps various chemotherapeutic drugs with different structures and mechanisms of action, including doxorubicin, paclitaxel, and vincristine, out of the cell, leading to insufficient intracellular drug accumulation and loss of cytotoxic effect. Numerous clinicopathological studies have confirmed that high expression of P-gp in breast cancer tissue is significantly associated with chemotherapy resistance and poor prognosis, especially in patients who have relapsed after neoadjuvant chemotherapy or multiple chemotherapy cycles, where P-gp expression levels are often significantly upregulated. In addition to P-gp, multidrug resistance also involves the synergistic participation of other efflux transporters such as breast cancer resistance protein (BCRP) and multidrug resistance-associated protein 1 (MRP1), collectively forming a physical barrier against insufficient intracellular drug accumulation. On the other hand, drug-resistant cells are often accompanied by mitochondrial energy metabolism reprogramming: to meet the large ATP demand of the continuous and efficient operation of efflux pumps such as P-gp, the mitochondrial oxidative phosphorylation activity of drug-resistant cells is usually enhanced, forming a phenotype of "adaptive upregulation of energy metabolism". This metabolic remodeling not only maintains the drug efflux function of P-gp, but also endows drug-resistant cells with stronger anti-apoptotic ability and survival advantage. It can be seen that there is an inherent vicious cycle between P-gp-mediated drug efflux and mitochondrial energy metabolism - metabolic activation drives efflux, and efflux consumes ATP, which in turn stimulates metabolism. Therefore, the search for safe and effective P-gp function inhibitors to reverse multidrug resistance has become a research hotspot in the field of tumor chemotherapy, and intervention targeting mitochondrial energy metabolism is considered a key breakthrough in breaking this drug resistance loop.

[0004] Natural products are an important source of innovative drug development, among which triterpenoids have attracted much attention in the field of anti-tumor treatment due to their diverse structures, rich biological activities, and low toxicity. α-Hederin, belonging to the oleanane-type pentacyclic triterpenoids, is mainly isolated and extracted from natural medicinal materials such as plants of the Araliaceae family (such as ivy and Acanthopanax senticosus) and Ranunculaceae family, and is one of the core active ingredients for the efficacy of traditional Chinese medicine. In recent years, numerous studies have confirmed that α-hederin has a specific killing effect on P-gp-mediated multidrug-resistant tumor cells, can reverse the drug resistance phenotype of tumor cells, and restore the sensitivity of chemotherapy drugs. However, natural α-hederin has problems such as insufficient target binding specificity and limited drug resistance reversal activity, making it difficult to directly develop it into a clinical drug. Yang et al. conducted targeted structural modification and functional group alteration using α-hederagenin as the parent nucleus. After multiple rounds of organic synthesis and activity screening, they finally obtained a novel α-hederagenin derivative—H6 (H6, a novel hederagenin derivative, reverses multidrug resistance in vitro and in vivo, Toxicology and Applied Pharmacology, 341, 2018, Pages 98-105). The drug resistance reversal mechanism of H6 differs from traditional P-gp inhibitors. It inhibits drug efflux by overactivating P-gp ATPase and disrupting energy metabolism, rather than directly downregulating P-gp expression. This mode of action does not lead to rapid drug resistance in tumor cells, providing a better compatibility option for combination chemotherapy. Although H6 is a modified product with the introduction of hydrophilic groups, it has extremely poor water solubility, with a solubility of only 0.3 ng / mL in water. Currently, the combined efficacy of H6 and chemotherapy drugs still needs improvement.

[0005] In recent years, copper death (cuproptosis) has attracted much attention as a novel form of programmed cell death. Its core mechanism involves intracellular copper overload leading to abnormal aggregation of lipid-acylated mitochondrial proteins and loss of iron-sulfur cluster proteins, thereby disrupting the tricarboxylic acid cycle and ultimately inducing cell death. Notably, copper death directly targets mitochondrial energy metabolism, which is highly consistent with the mechanism by which H6 reverses drug resistance by disrupting energy metabolism. Both rely on mitochondrial function as a core intervention. Elesclomol, a novel copper ion carrier, can specifically deliver copper ions to mitochondria and has been proven to effectively induce copper death in tumor cells. However, its poor water solubility and non-specific distribution in vivo remain significant obstacles to its clinical translation.

[0006] Currently, the main drug delivery methods for breast cancer include systemic administration (intravenous injection, oral administration) and local administration. While systemic chemotherapy remains the core approach, it has limitations such as insufficient drug accumulation at the tumor site and significant systemic toxicity. Especially in cases of multidrug resistance, overexpression of efflux pumps like P-gp further reduces the effective drug concentration at the tumor site, severely weakening the therapeutic effect. For patients with superficial breast cancer, skin metastases, and postoperative chest wall recurrence, local treatment strategies are increasingly attracting attention due to their precision and low toxicity. Intraductal drug delivery, explored in recent years, can directly deliver drugs to the site of cancer origin, but it requires advanced techniques and is only applicable to early lesions such as ductal carcinoma in situ, limiting its application. In contrast, soluble microneedle technology offers a more universal solution for local breast cancer treatment. Microneedles penetrate the stratum corneum of the skin in a minimally invasive manner, forming micron-sized drug channels that precisely deliver drugs to the tumor site, achieving the ideal drug delivery mode of "high concentration at the target site and low systemic exposure." Crucially, for drug-resistant breast cancer, microneedle delivery of locally high drug concentrations can effectively "overwhelm" the efflux capacity of P-gp, increase the transmembrane concentration gradient, and reverse the insufficient effective drug concentration caused by the efflux pump. Furthermore, microneedles are compatible with nanodelivery systems, encapsulating complex systems such as self-assembled nanoparticles to achieve programmed release at the tumor site.

[0007] Based on this, this study proposes an innovative combination therapy strategy, constructing a triple nano-self-assembled system of ilisimo, H6 molecules, and the chemotherapeutic drug doxorubicin hydrochloride, and further loading it into soluble microneedles for the treatment of drug-resistant breast cancer. In this system, H6 inhibits P-gp function by disrupting energy metabolism, increasing the accumulation of doxorubicin in drug-resistant cells; ilisimo-mediated copper death further attacks mitochondrial function, forming a double attack on energy metabolism with H6; and the nano-self-assembly technology enables controllable co-delivery and synergistic release of the three drugs. Microneedle delivery achieves highly efficient local drug administration and increases the effective drug concentration at the tumor site. This strategy is expected to overcome the limitations of traditional P-gp inhibitors and provide a novel solution for the treatment of drug-resistant malignant tumors. Summary of the Invention

[0008] In view of the shortcomings of the prior art, the present invention discovered that irismo can form supramolecular self-assemblies with two molecules, iposide derivatives and doxorubicin hydrochloride, under specific conditions. The particle size is less than 200 nm, and the dispersion is good, which can effectively improve the water solubility of the drug. Based on this, the nanoparticles are used to prepare transdermal microneedles to form a transdermal formulation for the treatment of breast cancer.

[0009] This invention provides a method for preparing a microneedle formulation. The microneedle tip is a self-assembled nanoparticle of hyaluronic acid mixed with a drug, and the microneedle substrate is polyvinylpyrrolidone. The nanoparticle is formed by the self-assembly of three molecules: hedyotis diffusa derivative, doxorubicin hydrochloride, and ilismoxol, through supramolecular intermolecular forces. The preparation method is as follows: the hedyotis diffusa derivative and ilismoxol are dissolved in dichloromethane, and doxorubicin hydrochloride is dissolved in methanol. The two are mixed evenly to form the oil phase. Sodium cholate aqueous solution is used as the aqueous phase. The oil phase is added to the first aqueous phase under ultrasonic crushing to obtain an oil-in-water phase. The oil-in-water phase is then added to the second aqueous phase under ultrasonic crushing. After completion, the organic solvent is evaporated under continuous stirring to obtain the nanoparticle. The molecular formula of the hedyotis diffusa derivative is Ci. 39 H 52 N2O3, the structural formula is shown below: Bn is benzyl.

[0010] The microneedles are prepared using the following method: self-assembled nanoparticles are washed with deionized water by ultrafiltration, and microneedles are prepared using a polydimethylsiloxane (PDMS) microneedle template. Hyaluronic acid is dispersed in the washed self-assembled nanoparticle aqueous solution with a concentration of 140 mg / mL and an average molecular weight of 100,000-200,000 Mw. This aqueous solution is added to the PDMS microneedle template, and the microneedle tips are prepared by centrifugation. Then, polyvinylpyrrolidone (PVP) is added to the mold as a microneedle support array with an average molecular weight of 10,000 Mw. After drying, the ilismo microneedles are obtained.

[0011] The mass ratio of the hedyotis diffusa derivative to ilismo is 5-20:1; the mass ratio of the hedyotis diffusa derivative to doxorubicin hydrochloride is 5-20:1.

[0012] The concentration of the hedyotis dichloromethane derivative is 5-20 mg / mL.

[0013] The volume ratio of dichloromethane to methanol is 1:0.5-2.

[0014] The sodium cholate aqueous solution has a mass concentration of 0.15%-0.3%.

[0015] In the first aqueous phase, the volume ratio of the oil phase to the aqueous phase is 1:5-20.

[0016] The volume ratio of the second aqueous phase to the first aqueous phase is 5-20:5-20.

[0017] The ultrasonic disruption was performed using a cell disruptor with a disruption power of 50% and a disruption time of 120 seconds.

[0018] The microneedle formulation is a transdermal drug delivery method.

[0019] The microneedle mold array has a total of 15×15 needles, a needle length of 1200 micrometers, a needle shape of a regular square pyramid, and a needle tip spacing of 800 micrometers.

[0020] The irismo, ivy alkaloid derivatives, and doxorubicin hydrochloride are supramolecular self-assembled compounds formed by intermolecular forces, requiring no carrier, resulting in nanoparticles with uniform particle size and good dispersibility. Attached Figure Description

[0021] Figure 1 Particle size distribution diagram of the formulation in Example 1.

[0022] Figure 2 Transmission electron microscope image of the formulation in Example 1.

[0023] Figure 3 Example 5: Scanning electron microscope image of the microneedle.

[0024] Figure 4 Example 5: Skin confocal laser microscopy image.

[0025] Figure 5 Example 6: Inverted fluorescence microscopy image of the skin.

[0026] Figure 6 Skin HE staining diagram from Example 6 Figure 7 Methylene blue skin staining images from Example 6 (A: unstained, B: stained) Detailed Implementation The present invention will be further illustrated below through embodiments. It should be understood that the embodiments of the present invention are merely provided for illustrative purposes and are not intended to limit the present invention. Therefore, any simple modifications to the present invention based on the method of the present invention are within the scope of protection claimed by the present invention.

[0027] Example 1 5 mg of hedyotis diffusa derivative molecule H6 and 1 mg of ilismo were dissolved in 1 mL of dichloromethane, and 1 mg of doxorubicin hydrochloride was dissolved in 0.5 mL of methanol. The two were mixed evenly to form the oil phase. The oil phase was added to 5 mL of 0.15% sodium cholate aqueous phase under ultrasonic disruption (100% power, 120 s) to obtain an oil-in-water phase. The oil-in-water phase was then added to a second aqueous phase of 20 mL of 0.15% sodium cholate aqueous solution under ultrasonic disruption (100% power, 120 s). After the process was completed, the organic solvent was evaporated while stirring continuously.

[0028] Example 2 20 mg of hedyotis diffusa derivative molecule H6 and 1 mg of irismol were dissolved in 1 mL of dichloromethane, and 1 mg of doxorubicin hydrochloride was dissolved in 1 mL of methanol. The two were mixed evenly to form the oil phase. The oil phase was added to 20 mL of 0.15% sodium cholate aqueous phase under ultrasonic disruption (50% power, 120 s) to obtain an oil-in-water phase. The oil-in-water phase was then added to a second aqueous phase of 5 mL of 0.3% sodium cholate aqueous solution under ultrasonic disruption (50% power, 120 s). After the process was completed, the organic solvent was evaporated while stirring continuously.

[0029] Example 3 10 mg of hedyotis diffusa derivative molecule H6 and 1 mg of ilismo were dissolved in 1 mL of dichloromethane, and 1 mg of doxorubicin hydrochloride was dissolved in 2 mL of methanol. The two were mixed evenly to form the oil phase. The oil phase was added to 10 mL of 0.3% sodium cholate aqueous phase under ultrasonic disruption (50% power, 120 s) to obtain an oil-in-water phase. The oil-in-water phase was then added to a second aqueous phase of 10 mL of 0.15% sodium cholate aqueous solution under ultrasonic disruption (50% power, 120 s). After the process was completed, the organic solvent was evaporated while stirring continuously.

[0030] Example 4 10 mg of hedyotis diffusa derivative molecule H6 and 1 mg of ilismolybdenum were dissolved in 1 mL of dichloromethane, and 1 mg of doxorubicin hydrochloride was dissolved in 0.5 mL of methanol. The two were mixed evenly to form the oil phase. The oil phase was added to 10 mL of 0.15% sodium cholate aqueous phase under ultrasonic disruption (80% power, 120 s) to obtain an oil-in-water phase. The oil-in-water phase was then added to a second aqueous phase of 5 mL of 0.3% sodium cholate aqueous solution under ultrasonic disruption (80% power, 120 s). After the process was completed, the organic solvent was evaporated while stirring continuously.

[0031] Example 5 The nanoparticle solution obtained in Example 1 was washed three times by ultrafiltration with deionized water. Hyaluronic acid with a concentration of 140 mg / mL and an average molecular weight of 100,000-200,000 Mw was added. After being slowly stirred until completely dissolved, the solution was added to a microneedle mold of polydimethylsiloxane PDMS. The mixture was centrifuged at 3000 rpm for 5 min, excess liquid was removed, and the solution was allowed to stand for 24 hours to evaporate moisture. An aqueous solution of polyvinylpyrrolidone (PVP) was added to the mold to serve as a microneedle support array. The concentration of PVP was 1.5 g / mL. The average molecular weight is 10,000 Mw. After standing for 48 hours and drying, the ilismo microneedles are obtained.

[0032] Example 6 The nanoparticle solution obtained in Example 2 was washed three times by ultrafiltration with deionized water. Hyaluronic acid with a concentration of 140 mg / mL and an average molecular weight of 100,000-200,000 Mw was added. After being slowly stirred until completely dissolved, the solution was added to a microneedle mold of polydimethylsiloxane PDMS. The mixture was centrifuged at 3000 rpm for 5 min, excess liquid was removed, and the solution was allowed to stand for 24 hours to evaporate moisture. An aqueous solution of polyvinylpyrrolidone (PVP) was added to the mold to serve as a microneedle support array. The concentration of PVP was 1.5 g / ml. The average molecular weight is 10,000 Mw. After standing for 48 hours and drying, the ilismo microneedles are obtained.

[0033] Comparative Example 1 Dissolve 10 mg of paclitaxel and 1 mg of irismol in 1 mL of dichloromethane, and dissolve 1 mg of doxorubicin hydrochloride in 2 mL of methanol. Mix the two thoroughly to obtain the oil phase. Under ultrasonic disruption (50% power, 120 s), add the oil phase to 5 mL of 0.3% sodium cholate aqueous phase to obtain the oil-in-water phase. Under ultrasonic disruption (50% power, 150 s), continue to add the oil-in-water phase to a second aqueous phase of 5 mL of 0.15% sodium cholate aqueous solution. After completion, evaporate the organic solvent while stirring continuously.

[0034] Comparative Example 2 10 mg of hedyotis diffusa derivative molecule H6 and 1 mg of paclitaxel were dissolved in 1 mL of acetone, and 1 mg of doxorubicin hydrochloride was dissolved in 0.5 mL of methanol. The two were mixed evenly to form the oil phase. The oil phase was added to the first aqueous phase of 10 mL of 0.15% sodium cholate under ultrasonic disruption (80% power, 120 s) to obtain the oil-in-water phase. The oil-in-water phase was then added to the second aqueous phase of 5 mL of 0.3% sodium cholate aqueous solution under ultrasonic disruption (80% power, 120 s). After the process was completed, the organic solvent was evaporated while stirring continuously.

[0035] Comparative Example 3 10 mg of hedyotis diffusa derivative molecule H6 and 1 mg of ilismolide were dissolved in 1 mL of dichloromethane, and 1 mg of doxorubicin hydrochloride was dissolved in 0.5 mL of acetone. The two were mixed evenly to form the oil phase. The oil phase was added to 20 mL of 0.15% sodium cholate aqueous phase under ultrasonic disruption (100% power, 120 s) to obtain an oil-in-water phase. The oil-in-water phase was then added to a second aqueous phase of 5 mL of 0.3% sodium cholate aqueous solution under ultrasonic disruption (80% power, 120 s). After the process was completed, the organic solvent was evaporated while stirring continuously.

[0036] Comparative Example 4 10 mg of hedyotis diffusa derivative molecule H6 and 1 mg of ilismo were dissolved in 1 mL of dichloromethane, and 1 mg of paclitaxel was dissolved in 0.5 mL of methanol. The two were mixed evenly to form the oil phase. The oil phase was added to 5 mL of 0.15% sodium cholate aqueous phase under ultrasonic disruption (80% power, 120 s) to obtain an oil-in-water phase. The oil-in-water phase was then added to a second aqueous phase of 10 mL of 0.3% sodium cholate aqueous solution under ultrasonic disruption (80% power, 120 s). After the process was completed, the organic solvent was evaporated while stirring continuously.

[0037] Comparative Example 5 10 mg of ipogonin derivative molecule H6 and 1 mg of irismol were dissolved in 1 mL of ethyl acetate, and 1 mg of doxorubicin hydrochloride was dissolved in 0.5 mL of methanol. The two were mixed evenly to form the oil phase. The oil phase was added to 10 mL of 0.15% polyvinyl alcohol aqueous phase under ultrasonic crushing (80% power, 120 s) to obtain an oil-in-water phase. The oil-in-water phase was then added to 5 mL of 0.3% polyvinyl alcohol aqueous solution as a second aqueous phase under ultrasonic crushing (80% power, 120 s). After the process was completed, the organic solvent was evaporated while stirring continuously.

[0038] Verification of Examples 1. The solutions obtained in Examples 1-4 and Comparative Examples 1-5 were filtered using a 0.45-micron microporous membrane. The particle size and polydispersity index of the resulting liquids were monitored using a laser particle size analyzer.

[0039] Table 1. Particle size and polydispersity index (PDI) of each embodiment The results are shown in Figure 1. The nanoparticles prepared in the embodiments of the present invention have a normal distribution, a particle size of less than 200 nm, a PDI of less than 0.3, and uniform particle size.

[0040] 2. The solution obtained in Example 1 was filtered through a 0.45-micron microporous membrane, and the resulting liquid was adsorbed onto a copper grid and its morphology was observed using a transmission electron microscope.

[0041] The results are as follows Figure 1 The nano-formulation prepared in the embodiments of the present invention shown is approximately spherical with relatively uniform particle size.

[0042] 3. The solutions obtained in Examples 1-4 and Comparative Examples 1, 3-5 were filtered using a 0.45-micron microporous membrane. 200 μL of the resulting liquid was diluted 5 times with dimethyl sulfoxide to break the emulsion. The drug content of ilismo was detected at 245 nm using a UV spectrophotometer, and the encapsulation rate of ilismo in the nano-formulation was calculated.

[0043] Table 2. Encapsulation efficiency of Examples 1-4 and Comparative Examples 1, 3-5 The results are shown in Table 2. The nano-formulation of ilismo prepared in this invention has a high encapsulation rate.

[0044] 4. The microneedles of Example 5 were observed using a scanning electron microscope.

[0045] The results are as follows Figure 3 As shown, the microneedle tip of the present invention is in the shape of a regular square pyramid, and the tip is intact.

[0046] 5. The morphology of some microneedles from Example 5 was observed using an inverted fluorescence microscope (excitation wavelength 488 nm, emission wavelength 590 nm).

[0047] The results are as follows Figure 4 The needle showed a red fluorescence of doxorubicin, indicating that the drug was successfully loaded.

[0048] 6. Press the microneedles of Example 6 onto the skin of the rat's back for 3 minutes. After removing the microneedles, stain the microneedle insertion area with methylene blue. Remove the excess staining agent after 1 minute and observe and photograph the results.

[0049] Methylene blue can be retained and stained at sites where the skin is punctured. Results show... Figure 7 As shown, the skin sites created by effective microneedle penetration were stained with methylene blue, indicating that the microneedles successfully penetrated the rat skin.

[0050] 7. Press the microneedles of Example 6 onto the skin of the rat's back for 3 minutes. Remove the microneedles and sacrifice the rat 1 hour later. Dissect and remove the skin from the back where the microneedles were inserted. Observe under an inverted fluorescence microscope (excitation wavelength 488nm, emission wavelength 590nm).

[0051] The results are as follows Figure 5 The image shows that the microneedle tip left a hole on the surface of the rat's skin, and the red color represents the distribution of doxorubicin, indicating that doxorubicin diffused to the surrounding skin.

[0052] 8. Press the microneedles of Example 6 onto the skin of the rat's back for 3 minutes. After removing the microneedles, euthanize the rat, dissect and remove the skin from the back where the microneedles were inserted, fix it in 4% paraformaldehyde, embed it in paraffin, and then perform tissue sectioning and hematoxylin-eosin staining for observation.

[0053] Skin hematoxylin-eosin slices as shown Figure 6 The image shows that microneedles create pinhead-shaped holes on the skin surface.

Claims

1. A method for preparing microneedles, characterized in that, The microneedles are composed of self-assembled hyaluronic acid-drug mixed nanoparticles, with polyvinylpyrrolidone (PVP) as the substrate. The microneedles are prepared using the following method: the self-assembled nanoparticles are washed with deionized water via ultrafiltration; microneedles are prepared using a polydimethylsiloxane (PDMS) microneedle template; hyaluronic acid is dispersed in an aqueous solution of the washed self-assembled nanoparticles at a concentration of 140 mg / mL with an average molecular weight of 100,000-200,000 Mw; this aqueous solution is added to the PDMS microneedle template; the microneedle tips are prepared by centrifugation; and then PVP is added to the mold as a microneedle support array. The average molecular weight of PVP is 10,000 Mw. Mw, after drying, yields the ilismo microneedles; the nanoparticles are formed by the self-assembly of three molecules—hederine derivative, doxorubicin hydrochloride, and ilismo—through supramolecular intermolecular forces, using the following preparation method: hederine derivative and ilismo are dissolved in dichloromethane, and doxorubicin hydrochloride is dissolved in methanol. The two are mixed thoroughly to form the oil phase; sodium cholate aqueous solution is used as the aqueous phase. The oil phase is added to the first aqueous phase under ultrasonic crushing to obtain an oil-in-water phase. The oil-in-water phase is then added to the second aqueous phase under ultrasonic crushing. After completion, the organic solvent is evaporated under continuous stirring to obtain the nanoparticles; the molecular formula of the hederine derivative is C. 39 H 52 N2O3, the structural formula is shown below: Bn is benzyl.

2. The method for preparing microneedles according to claim 1, characterized in that, The concentration of the hedyotis dichloromethane derivative is 5-20 mg / mL.

3. The method for preparing microneedles according to claim 1, characterized in that, The volume ratio of dichloromethane to methanol is 1:0.5-2.

4. The method for preparing microneedles according to claim 1, characterized in that, The sodium cholate aqueous solution has a mass concentration of 0.15%-0.3%.

5. The method for preparing microneedles according to claim 1, characterized in that, In the first aqueous phase, the volume ratio of the oil phase to the aqueous phase is 1:5-20.

6. The method for preparing microneedles according to claim 1, characterized in that, The volume ratio of the second aqueous phase to the first aqueous phase is 5-20:5-20.

7. The method for preparing microneedles according to claim 1, characterized in that, The mass ratio of the hedyotis diffusa derivative to ilismo is 5-20:1; the mass ratio of the hedyotis diffusa derivative to doxorubicin hydrochloride is 5-20:

1.

8. The method for preparing microneedles according to claim 1, characterized in that, The ultrasonic disruption was performed using a cell disruptor with a disruption power of 50% and a disruption time of 120 seconds.

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