A dutasteride nano-suspension, dissolvable microneedle and preparation method thereof

Abstract

This invention provides a dutasteride nanosuspension. It also provides soluble microneedles loaded with the dutasteride nanosuspension. The DUT nanosuspension is prepared using an antisolvent method combined with high-pressure homogenization to improve solubility and stability. Combined with microneedle drug delivery technology, the dutasteride nanosuspension is loaded onto soluble microneedles for topical skin administration, reducing the systemic side effects that may result from long-term oral DUT. Simultaneously, it increases the drug concentration of DUT in the skin layer, especially in hair follicles, thereby enhancing drug efficacy. Furthermore, the microneedles create microporous channels in the stratum corneum and epidermis, facilitating the smooth penetration of dutasteride through the stratum corneum, increasing its transdermal permeability, and improving transdermal absorption. This provides a research foundation for the clinical application and further development of dutasteride transdermal drug delivery for the treatment of androgenetic alopecia.

Description

Technical Field

[0001] This invention relates to a dutasteride nanosuspension, soluble microneedles, and their preparation methods. It belongs to the field of pharmaceutical formulations. Background Technology

[0002] Androgenetic alopecia (AGA) is a common, chronic, progressive hair loss condition that primarily affects hair follicles in the crown and temporal regions of the scalp. The main mechanism involves the action of dihydrotestosterone (DHT), a metabolite of testosterone, on the hair follicles. After binding to androgen receptors in the hair follicles, DHT inhibits the hair follicle's growth cycle, leading to thinning and softening of the hair. Furthermore, DHT may cause changes in blood circulation to the hair follicles, further impairing their function. It affects a large number of men and women. Its characteristic gradual thinning and receding hairline impose a significant psychological and social burden on patients.

[0003] Current drug treatments for AGA include minoxidil and finasteride, which can slow the hair loss process and promote hair growth. Finasteride (FIN) is a selective type II 5α-reductase inhibitor that has been approved by the FDA for the treatment and prevention of AGA. FIN works by inhibiting type II 5α-reductase, preventing testosterone from being converted into the more potent dihydrotestosterone, thereby reducing the level of dihydrotestosterone in the blood and hair follicles.

[0004] Dutasteride (DUT) is an analogue of finasteride (FIN), a white to pale yellow powder with a melting point of 242-250°C. It is insoluble in water but soluble in ethanol (44 mg / ml), methanol (64 mg / ml), and polyethylene glycol 400 (4 mg / ml). It is also a second-generation 5α-reductase inhibitor, capable of inhibiting both type I and type II 5α-reductase. Compared to finasteride, its efficacy in inhibiting type I 5α-reductase is 3 times greater, and its efficacy in inhibiting type II 5α-reductase is 100 times greater. Clinical trials have shown that DUT is superior to FIN in increasing hair volume and improving follicle miniaturization. Side effects are similar; oral DUT can cause serious systemic adverse reactions, such as gynecomastia, decreased libido, erectile dysfunction, ejaculatory dysfunction, and mood disorders.

[0005] Application No.: CN201910164118.0, Invention Title: A Dutasteride and a Composition Capsule for Treating Hair Loss, discloses a dutasteride and a composition capsule containing dutasteride. Each dutasteride capsule of this invention contains 0.125 mg of dutasteride, and each composition capsule contains 0.125 mg of dutasteride and 0.3-0.4 mg of minoxidil. By significantly reducing the effective dose of dutasteride per capsule, it does not affect the treatment of moderate to severe benign prostatic hyperplasia (only four capsules are needed at a time), and can be used in combination with minoxidil at a low dose to effectively treat male androgenetic alopecia. Application No.: CN201880045913.1, Invention Title: Topical Composition for Dutasteride, comprising 0.01 wt% to 0.06 wt% of dutasteride, 25 wt% to 35 wt% of medium-chain triglycerides, 25 wt% to 35 wt% of ethanol and 35 wt% to 45 wt% of castor oil based on the total weight of the composition, wherein the dutasteride contained in the composition provides a daily dose of 0.1 to 0.5 mg. Due to the water insolubility of dutasteride, formulation is difficult. CN202010975978.5, entitled "A Method for Preparing Composite Drug-Loaded Microspheres via Emulsification and Chemical Crosslinking and Its Application," describes a method that involves adding a hydrophobic drug to a hydrophilic surfactant to increase its wettability, followed by high-pressure homogenization to shear the hydrophobic drug and form a uniformly dispersed drug suspension. This suspension is then added to the aqueous phase of a hydrophilic polymer to form a mixed phase, which is then added to an oil phase pre-emulsified with an emulsifier. A crosslinking agent is then added for chemical crosslinking, thereby forming microspheres loaded with the hydrophobic drug. The hydrophobic drug is finasteride, dutasteride, terazosin, or tetrazolium. This application only prepares drug-loaded microspheres for oral administration.

[0006] There are reports on the preparation of finasteride into microneedles, such as patent application number CN202010083165.5, "A Nanolipid Carrier Microneedle for Treating Hair Loss and Its Application," which provides a nanolipid carrier microneedle for treating hair loss, comprising: a) a needle tip portion, the needle tip portion comprising a finasteride nanolipid carrier and a needle tip matrix; and b) a base portion, the base portion comprising a base matrix. This invention also provides the application of this nanolipid carrier microneedle in the preparation of a drug for treating androgenetic alopecia. Application No.: CN202310124145.1, Invention Title: A Microneedle for Treating Hair Loss and Its Preparation Method. This invention relates to a microneedle for treating hair loss and its preparation method. The method includes mixing retinoic acid, diphenylcyclopropenone, spironolactone, finasteride, minoxidil, botulinum toxin type A, balsam extract, henna extract, and cerium oxide-loaded nanoenzyme to obtain a mixed solution; adding sodium hyaluronate to obtain microneedle matrix solution A; mixing silk fibroin solution, proline, serine, and glycine to obtain microneedle matrix solution B; preparing a PVP-K90 solution as a microneedle backing matrix solution C; coating microneedle matrix solution B into the groove of a PDMS tank; taking microneedle matrix solution A and placing it in the cavity of the PDMS tank groove; dripping the microneedle backing matrix solution C onto the mold surface; and centrifuging to separate the microneedles. The length of the microneedles obtained by this method is 0.5 mm. Application No.: CN201910231043.3, Invention Title: A Soluble Microneedle for Promoting Hair Growth and its Preparation Method. The invention describes a soluble microneedle for promoting hair growth, comprising a base, a soluble polymer needle body located on the base, and a needle tip carrying a substance that promotes hair growth. A method for preparing the soluble microneedle for promoting hair growth includes the following steps: 1) preparing a PDMS microneedle array mold; 2) preparing an aqueous solution of a soluble polymer containing a substance that promotes hair growth; 3) preparing a soluble polymer microneedle array carrying the substance that promotes hair growth. This invention solves the technical problems of existing topical drugs, such as low transdermal penetration and uneven distribution; painful subcutaneous injection of interleukin-2; significant side effects from oral administration of finasteride; and high cost of hair transplantation.Because different matrix materials have a significant impact on the molding performance, mechanical properties, and drug release performance of microneedles (Zhuang J, Rao F, Wu D, et al. Study on the fabrication and characterization of tip-loaded dissolving microneedles for transdermal drug delivery[J]. European Journal of Pharmaceutics and Biopharmaceutics, 2020, 157: 66-73. Al-Japairai KAS, Mahmood S, Almurisi SH, et al. Current trends in polymer microneedle for transdermal drug delivery[J]. International journal of pharmaceutics, 2020, 587: 119673.), there are currently no literature reports on the preparation of dutasteride into microneedles. Summary of the Invention

[0007] The present invention provides a dutasteride nanosuspension, and another technical solution of the present invention provides soluble microneedles loaded with dutasteride nanosuspension and a method for preparing the same.

[0008] This invention provides a dutasteride nanosuspension containing dutasteride at 0.4 mg / mL to 2 mg / mL; a stabilizer at 0.25% to 2% w / v; and the remainder being an organic solvent.

[0009] The organic solvent is one of methanol, ethanol, acetone, and chloroform.

[0010] The stabilizer is one or a mixture of two or more of the following: Tween 80, P188, P407, HPMC, PVA1788, SDS, PVPK30, and OP-10.

[0011] More preferably, the organic solvent is methanol; the stabilizer is PVA1788 with a content of 0.5% w / v; and the content of dutasteride is 1 mg / mL.

[0012] This invention also provides a method for preparing the dutasteride nanosuspension, characterized in that: it uses an antisolvent precipitation method to prepare the nanosuspension, comprising the following steps:

[0013] a. Dissolve dutasteride powder in a good solvent;

[0014] b. Under magnetic stirring, the good solvent of the drug is rapidly injected into the aqueous solution containing the stabilizer using a syringe, the organic solvent is evaporated, and the solution is homogenized under high pressure to obtain a nano-suspension.

[0015] The term "good solvent" refers to a solvent that can dissolve tadrone, including, but not limited to, organic solvents.

[0016] In step b, the homogenization pressure is 1000 bar and the homogenization time is 15 min.

[0017] The present invention also provides a soluble microneedle loaded with dutasteride nanosuspension, which is prepared from the dutasteride nanosuspension and DMNs matrix material.

[0018] The DMNs matrix material is a composite of one or more of PVP K30, HA, and PVA.

[0019] More preferably, the DMNs matrix material is one of PVP K30, HA (40-60w), HA (20-40w), HA (10w), PVA, PVP K30-HA (10W) (1:1), PVP K30-HA (20-40w) (1:1), and PVP K30-HA (40-60w) (1:1); preferably, the DMNs matrix material is PVP K30-HA (10W) (1:1).

[0020] The present invention also provides a method for preparing the soluble microneedles, comprising the following steps:

[0021] a. Take two matrix materials, PVP K30 and HA (10w) powder, mix them thoroughly in a 1:1 ratio, add the dutasteride nano suspension as described in claim 1 or 2, let it stand or centrifuge it to fully dissolve it while removing air bubbles, and the polymer solution is obtained.

[0022] b. Pour the polymer solution quantitatively into the mold, and use the vacuum method to repeatedly evacuate the mold needle body part so that the solution completely fills the mold. Then put it into an oven at 25-50℃ to dry.

[0023] c. Demolding: Remove the mold and use tweezers to peel off the microneedles on the mold.

[0024] In step a, the settling time is 2 hours; in step b, the drying temperature is 30°C and the drying time is 6 hours.

[0025] The present invention also provides the use of the soluble microneedles of the aforementioned loaded dutasteride nanosuspension in the preparation of a medicament for treating androgenetic alopecia.

[0026] This invention employs an antisolvent method combined with high-pressure homogenization to prepare dutasteride nanosuspension, thereby improving the bioavailability of poorly soluble drugs. Nanosuspension is a multiphase dispersion system composed of nanoscale drug particles, using a small amount of surfactant or polymeric material as a stabilizer. It has the following characteristics: (1) Improved bioavailability of drugs, especially poorly soluble drugs: Compared with ordinary suspensions, nanosuspension has a smaller particle size and a larger surface area, greatly increasing the drug's dissolution rate and solubility, thus improving the bioavailability of drugs, especially poorly soluble drugs; (2) High drug loading and low excipient usage: Drug particles in its nanosuspension do not require any carrier or tool. Compared with liposome-based drug delivery systems, nanosuspension has a higher drug loading and lower excipient usage, avoiding the toxic side effects caused by large amounts of excipients; (3) Simple preparation process: The preparation process is relatively simple, saving costs.

[0027] This invention utilizes soluble microneedles to deliver dutasteride nanosuspension, achieving a dual enhancement of drug penetration. The dutasteride nanosuspension loaded on the soluble microneedles directly delivers the drug to deep skin lesions, significantly reducing drug loss due to the stratum corneum during transdermal transport and improving transdermal efficiency. It increases the concentration of dutasteride in the skin layer, especially in hair follicles, thereby enhancing therapeutic efficacy. The matrix material of the soluble microneedles is primarily hyaluronic acid, which is non-irritating to the skin during administration. It also has a good adjunctive effect in the treatment of hair loss.

[0028] Dutasteride, which has poor water solubility, was prepared into a nano-suspension, which significantly improved the drug's solubility and absorption. Combined with microneedle technology, a soluble matrix material was selected as the drug-carrying matrix to make a microneedle patch to promote transdermal drug absorption, forming a dual penetration-enhancing effect.

[0029] In summary, the preparation of DUT nanosuspensions using an antisolvent method combined with high-pressure homogenization improves solubility and stability. Combined with microneedle drug delivery technology, dutasteride nanosuspensions are loaded onto soluble microneedles for topical skin administration, reducing potential systemic side effects from long-term oral DUT administration. This also increases the drug concentration of DUT in the skin layer, particularly in hair follicles, thereby enhancing therapeutic efficacy. Furthermore, the microneedles create microporous channels in the stratum corneum and epidermis, facilitating dutasteride's permeability through the stratum corneum, increasing its transdermal permeability and absorption. This provides a research foundation for the clinical application and further development of dutasteride transdermal administration in the treatment of androgenetic alopecia. This approach has significant theoretical and practical implications for improving treatment outcomes, reducing side effects, and enhancing drug bioavailability and convenience in patients with androgenetic alopecia. Attached Figure Description

[0030] Figure 1 Stabilizer type selection test

[0031] Figure 2 Screening test of the dosage of suspending agent PVA1788

[0032] Figure 3 Organic solvent selection test

[0033] Figure 4 Dutasteride Concentration Selection Test

[0034] Figure 5 Homogenization Time Selection Experiment

[0035] Figure 6 Dissolution graphs of microneedles at different times

[0036] Figure 7 The appearance of the dutasteride suspension microneedles of this invention (wherein, A: DUT-NS (in a vial); B: DUT-NS-DMNs (crescent-shaped); C: image of the microneedles taken under a macro lens).

[0037] Figure 8 Scanning electron microscope (SEM) images of the dutasteride suspension microneedles of this invention (where A: DUT-NS; B: DUT-NS-DMNs).

[0038] Figure 9 DSC thermogram of dutasteride suspension microneedles of this invention

[0039] Figure 10 Fourier transform infrared spectrum experimental diagram

[0040] Figure 11 Hair growth chart

[0041] Figure 12 Hair follicle histological observation results Detailed Implementation

[0042] Example 1: Preparation of soluble microneedles from the loaded dotasteride nanosuspension of the present invention

[0043] prescription

[0044]

[0045] Preparation method:

[0046] Accurately weigh 50 mg of dutasteride and dissolve it in 2 mL of methanol. This solution is denoted as solution A.

[0047] Accurately weigh 250 mg of PVA1788 and dissolve it in 50 mL of pure water by magnetic stirring. This solution is designated as solution B.

[0048] With magnetic stirring, solution A was rapidly injected into solution B using a syringe, followed by magnetic stirring overnight to allow methanol to evaporate. The suspension was then subjected to high-pressure homogenization (1000 bar, 15 min) to obtain a dutasteride nanosuspension (DUT-NS) with uniform particle size distribution.

[0049] Take 10 mL of the dutasteride nanosuspension prepared above, and weigh out 300 mg each of sodium hyaluronate and PVP K30. Dissolve them thoroughly in the suspension, let stand for 2 hours to remove air bubbles, and obtain the polymer solution. Pour 1 mL of the polymer solution into a microneedle mold, place the mold in a vacuum drying oven, and repeatedly evacuate (2-3 times) to ensure the solution completely fills the needle body of the mold. Then, dry in a 30℃ oven for 6 hours. Remove the mold and carefully peel off the microneedles with tweezers to obtain soluble microneedles loaded with dutasteride nanosuspension (DUT-NS-DMNs).

[0050] Example 2: Screening test of preparation process for dutasteride nanosuspension (DUT-NS)

[0051] 1. Preparation method

[0052] Nanoparticle suspensions were prepared by antisolvent precipitation method. First, the drug powder was dissolved in an organic solvent. Then, under magnetic stirring, the drug solution was rapidly injected into an aqueous solution containing a stabilizer using a syringe. After evaporating the organic solvent, the solution was homogenized under high pressure to obtain nanoparticle suspensions.

[0053] 2. Single-factor analysis of prescriptions

[0054] Following the above preparation method, the types and amounts of single stabilizers, organic solvents, and composite stabilizers were investigated.

[0055] 1) Types of stabilizers

[0056] Nanoparticle suspensions were prepared using the antisolvent precipitation method described above. With other conditions kept constant, the effects of eight commonly used suspending agents of different types on particle size were investigated. Using particle size, polydispersity index (PDI), and zeta potential as indicators, the optimal suspending agent was selected (see Table 1). Figure 1 ).

[0057] Table 1 Stabilizer Selection Test

[0058]

[0059] Based on the above results, dutasteride exhibits good particle size (292 nm) and PDI (0.122) when using PVA1788 as a suspending agent. Therefore, PVA1788 was ultimately selected as a stabilizer for further investigation.

[0060] 2) Stabilizer dosage

[0061] With other factors kept constant, PVA1788 was used as a suspending agent (or stabilizer) and different dosages (0.25%, 0.5%, 1%, 1.5%, 2%) were prepared. The optimal suspending agent dosage was screened using particle size, polydispersity index (PDI), and zeta potential as indicators (see Table 2). Figure 2 ).

[0062] Table 2 Screening test of PVA1788 dosage as a suspending agent

[0063]

[0064] Based on the above results, dutasteride exhibits good particle size (315 nm) and PDI (0.148) when the amount of PVA1788 is 0.5%. Therefore, the stabilizer amount of 0.5% was finally selected for further research.

[0065] 3. Types of good solvents

[0066] After determining the suitable PVA1788 concentration for preparing the nanosuspension, the effect of solvents on the particle size of the formed dutasteride nanosuspension was evaluated. The solvents investigated were: ethanol, methanol, acetone, and chloroform (see Table 3). Figure 3 ).

[0067] Table 3 Organic Solvent Selection Test

[0068]

[0069] The experimental results indicate that methanol is a suitable solvent because it produces the smallest DUT-NS particle size compared to ethanol and acetone. Furthermore, it was observed that DUT-NS prepared with methanol exhibited better PDI compared to acetone and ethanol. Therefore, methanol was ultimately chosen as the organic solvent for further research.

[0070] 4. Drug concentration

[0071] To achieve optimal size and distribution in the dutasteride nanosuspension, the effect of drug concentration was evaluated. Drug concentrations ranged from 0.4 mg / mL to 2 mg / mL, while the concentration of PVA1788 was maintained at 0.5%, with methanol as the solvent. (See Table 4) Figure 4 )

[0072] Table 4. Dutasteride Concentration Selection Test

[0073]

[0074] As the drug concentration increased from 0.5 mg / mL to 1 mg / mL, the particle size decreased from 302 ± 6.4 nm to 250 ± 3.4 nm. However, as the drug concentration increased from 1 mg / mL to 2 mg / mL, the particle size did not change significantly (p > 0.05). The final designed drug concentration was 1 mg / mL for subsequent studies.

[0075] 5. Homogenization time

[0076] With fixed surfactant (PVA = 0.5% w / v) concentration, drug concentration (DUT = 1 mg / mL), and methanol as solvent, the effect of homogenization was investigated by varying the averaging time. The averaging pressure was fixed at 1000 bar, and homogenization times were 5, 10, 15, and 20 minutes to determine the effect (see Table 5). Figure 5 ).

[0077] Table 5 Homogenization Time Selection Experiment

[0078]

[0079] As homogenization time increased, the particle size decreased, but after 15 minutes, no significant change was observed (p>0.05). The PDI was minimized at 15 minutes (0.06), and the homogenization time was ultimately determined to be 15 minutes.

[0080] Example 3: Preparation process and parameter screening test of the microneedles of the present invention.

[0081] 1. Screening of DMN matrix materials

[0082] Since different matrix materials significantly affect the molding performance, mechanical properties, and drug release performance of DMNs, the toughness and strength of the matrix material are particularly important when preparing DMNs using the molding method. Otherwise, the microneedles are easily broken during demolding, resulting in incomplete DMN patches. To find ideal materials for DMN preparation, commonly used soluble polymer materials were screened. The solubility of each material in DUT-NS, the amount of bubbles after standing for 2 hours after dissolving in DUT-NS, the drying time required at 30°C, the ease of demolding, and the needle content after demolding were all evaluated and scored. The material with the highest score was further optimized, ultimately determining the basic material for soluble microneedles. Detailed scoring criteria are shown in Table 6.

[0083] Table 6. Screening and Scoring Table for DMN Matrix Materials

[0084]

[0085] DMN was prepared using PVP K30, HA, PVA and composite materials. The types of matrix materials were screened based on the solubility of each material in SA-LIP, the amount of bubbles after standing for 2 hours after dissolving in SA-LIP, the drying time required at 30℃, the ease of demolding, and the needle content after demolding. The results are shown in Table 7.

[0086] Table 7 Performance evaluation results of soluble microneedle materials

[0087]

[0088] As shown in the table, single matrix materials did not score highly. For example, DMN prepared from PVP K30 was brittle and difficult to demold. PVA, a common material for preparing DMN, was found to have polymer solutions that were difficult to dry completely during the preparation process. Although the DMN obtained after long-term drying had excellent flexibility, the needles were relatively soft and lacked sufficient mechanical strength. For the same material, there was also a significant difference in the molecular weight of HA. HA (40-60w) and HA (20-40w) had larger molecular weights and stronger water absorption, which made it difficult to completely dissolve the polymer solution prepared at 50mg / mL. The microneedles prepared from HA (10w) were the best among single matrix materials, but the DMN needles were found to be prone to breakage during demolding.

[0089] Based on the above results, it is evident that using a single material alone is insufficient to prepare ideal DMN. DMN prepared with HA as the matrix lacks sufficient mechanical strength but has excessive toughness, while microneedles prepared with PVP K30 exhibit excessively high mechanical strength, leading to brittleness and insufficient toughness. Therefore, a combination of PVP K30 and HA is considered for preparing soluble microneedles. It can be seen that the DMN obtained after combining toughness and brittleness materials has a higher overall performance score, resolving the issues of difficult demolding and high needle content.

[0090] 2. DMN forming process

[0091] After determining that soluble microneedles should be prepared using PVP K30 and HA (10w) in a 1:1 ratio as matrix materials, the two matrix material powders were thoroughly mixed in a 1:1 ratio and then dissolved in DUT-NS solution. The solution was allowed to stand or centrifuged to fully dissolve the microneedles while removing air bubbles, yielding the polymer solution. The polymer solution was quantitatively poured into a mold, and vacuum was repeatedly applied to ensure the solution completely filled the needle portion of the mold. The mold was then dried in an oven at 25-50℃. The mold was removed, and the DMN on the mold was carefully peeled off with tweezers. The preparation process was optimized based on the molding results.

[0092] During the exploration of the DUT-NSDMNs molding process, it was found that, firstly, both static standing and centrifugation can effectively remove air bubbles from the polymer solution. However, centrifugation may cause the two materials to separate into layers, with the upper layer being more dilute than the lower layer. Secondly, the higher the oven temperature, the shorter the drying time. However, microneedles obtained at high temperatures (above 40°C) will shrink, resulting in an uneven overall DUT-NS-DMNs patch. Furthermore, the higher the temperature, the greater the impact on the stability of DUT-NS.

[0093] Therefore, after comprehensive consideration, it was decided to remove air bubbles by letting the mixture stand for 2 hours, set the drying temperature to 30℃, and the drying time to 6 hours. The resulting microneedles had a good appearance and high needle content, while also maximizing the preservation of drug activity.

[0094] 3. Dissolution of microneedles at different times

[0095] To investigate the dissolution of microneedle tips at different times after skin penetration, microneedles were applied to the hairless skin area on the backs of mice. After a certain period, the microneedles were removed and observed under a microscope. The results are as follows: Figure 6 As shown, the microneedle tip dissolves rapidly, becoming almost completely dissolved within 5 minutes.

[0096] Example 4: Quality assessment of the dutasteride suspension microneedles of the present invention

[0097] 1. Appearance (see Figure 7 )

[0098] 2. Scanning electron microscope

[0099] Scanning electron microscopy observation of DUT-NS and DUT-NS-DMNs results are as follows: Figure 8 As shown;

[0100] 3. Differential scanning calorimetry characterization

[0101] DSC thermograms were obtained using a differential scanning calorimeter (Hengjiu, Beijing). 10 mg of powder samples (dutasteride raw material, dutasteride lyophilized suspension powder, dutasteride suspension microneedles) were weighed and analyzed at 25–300 °C (15 °C / min).

[0102] DSC images of dutasteride raw material (DUT), dutasteride suspension lyophilized powder (DUT-NS), and dutasteride suspension microneedles (DUT-DMN) are shown below. Figure 9 As shown.

[0103] Dutasteride has a melting point of 242-250℃. DSC analysis confirmed that the drug retains its crystallinity when added to NS and MN formulations.

[0104] 5. Fourier Transform Infrared Spectroscopy Experiment

[0105] FTIR analysis of the corresponding NS and DMN in pure DUT was performed using an Agilent infrared spectrometer (USA) to determine structural changes in the formulation. Attenuated total reflectance (ATR) was used to perform 64 scans on the samples, with transmittance ranging from 4000 to 4000 cm⁻¹. -1 Evaluation was conducted within the wavenumber range, with a resolution of 4 cm. -1 .

[0106] The infrared spectra of dutasteride raw material (DUT), dutasteride suspension (DUT-NS), and dutasteride suspension microneedles (DUT-DMN) are as follows: Figure 10 As shown in the figure, the infrared spectra of the three samples exhibited similar peak shapes. Some minor differences also existed, primarily in peak intensity and relative position. Despite these differences, they were insufficient to alter the overall peak shape, thus demonstrating the fundamental consistency in the molecular structure of the three samples. This indicates the relative stability of the drug's molecular structure during formulation.

[0107] The beneficial effects of the present invention are demonstrated below through specific pharmacodynamic tests.

[0108] Experimental Example 1: Pharmacodynamic Study of Dutasteride Suspension Microneedles in Mice

[0109] 1. Laboratory animals

[0110] C57BL / 6 mice

[0111] 2. Preparation of experimental solutions

[0112] Preparation of testosterone suspension: First, prepare a 100 mg / mL Tween 80 solution using sterile ultrapure water. Then, thoroughly grind and mix the testosterone powder with the 100 mg / mL Tween 80 solution to prepare a 10 mg / mL testosterone suspension. The suspension is effective for 7 days after preparation.

[0113] Preparation of minoxidil solution: Weigh 0.5 g of minoxidil and dissolve it in 100 mL of a mixed solution of ethanol:1,2-propanediol:ultrapure water (54:26:20). Stir and heat to dissolve, preparing a 0.5% minoxidil solution. Store in a refrigerator at 4°C for later use.

[0114] 3. Establishment of an androgenetic alopecia (AGA) model

[0115] After the animal adaptation period, the animals were anesthetized, and then the hair in the area to be shaved, parallel to the back, under the neck of each mouse was removed using a razor (the shaved area was approximately 3.2 cm long, 2.5 cm wide, and 8 cm² in area). After shaving, depilatory cream was applied to remove the hair, and this area was used as the observation area for hair removal. After hair removal, the depilatory cream on the back of the mouse was wiped off with a water-soaked wipe, and then the hair removal area and surrounding hair were washed again with drinking water. The day of hair removal was defined as (D-1). Residual hair was removed, and it was confirmed that the current hair growth of the mouse was in the resting phase (the skin was pink and without damage). 24 hours after hair removal treatment (D0), the skin condition of the animals was observed, and the mice were randomly divided into groups for modeling according to the skin or body weight after hair removal. Except for the normal control group which was injected with 0.1 mL of physiological saline per mouse, the other groups of mice were injected subcutaneously with testosterone suspension at a dose of 1 mg per mouse and a volume of 0.1 mL per mouse around the hair removal area on the back of the neck, and the injection was continued for 23 days. Starting on day 1, the corresponding test product and control product were evenly applied or administered orally to all hairless areas on the neck and back of all mice once a day for 22 consecutive days.

[0116] 4. Grouping and administration of experimental animals

[0117] Table 8. Grouping and administration of experimental animals

[0118]

[0119] 5. Hair growth status and score

[0120] Observe the hair growth in the bald areas of mice in each experimental group daily, and record the changes in skin color in the bald areas: the skin changes from pink to black, and then hair growth begins to appear. Mice in each experimental group are photographed at predetermined time intervals after drug administration. Figure 11 As shown.

[0121] like Figure 12 As shown, compared with the control group, the testosterone-induced model group exhibited significantly slower hair growth. In the control group, the skin began to turn from pink to black around day 5, while in the model group, the time for skin to turn from pink to black was extended to after 10 days. In the control group, hair growth was almost complete by day 15, while in the model group, only a small amount of hair shaft had begun to grow by day 15. Furthermore, the hair follicles in the model group showed significantly miniaturized morphology, were in the resting phase, and had a significantly reduced number of follicles, all indicating successful model establishment.

[0122] Compared with the model group, mice in the positive control group, NS group, and DUT-DMN group showed varying degrees of hair regeneration under different drug treatments. The DUT-DMN group showed superior hair regeneration compared to the positive control group, which in turn was superior to the NS group. The results indicate that microneedles can significantly promote hair regeneration in mice, even exceeding the effect of the positive control drug miminoxidil.

[0123] 6. Observe the morphology of mouse hair follicles in tissue sections.

[0124] After the hair growth observation experiment, three mice were randomly selected from each group and euthanized by cervical dislocation. The hair on the experimental area of ​​the mouse's back was shaved off with an electric shaver. Residual hair was then removed with depilatory cream. After washing the skin with saline, the skin on the back was dissected with a scalpel, and the subcutaneous tissue and fat were separated to obtain an area of ​​approximately 1 cm². 2 Mouse skin was repeatedly rinsed with physiological saline, and the surface moisture was blotted dry with filter paper. It was then placed in fresh tissue fixative and fixed for at least 24 hours. Paraffin sections were prepared, and hair follicles were observed and photographed under a microscope. Figure 12 .

[0125] The effect of DUT-NS-DMNs on hair follicle morphology in an AGA model was studied to evaluate the therapeutic effect of DUT-NS-DMNs on androgenetic alopecia. Except for the blank control group, the other groups were given different treatment interventions after topical application of testosterone solution every day, namely (1) blank control group: only topical application of physiological saline, (2) model group: AGA mice did not receive any intervention treatment, (3) positive drug control group, (4) DUT-NS group and (5) DUT-NS-DMNs group: all mice in the nape and back hairless area were evenly applied or given the corresponding test product and control product every day, and (6) blank DMNs group: AGA mice were given blank microneedles topically.

[0126] The histological observations of hair follicles in each group of mice are shown in the figure above. The results showed that the blank group and the blank DMNs group had longer and more numerous hair follicles with darker hair shaft pigmentation, and most follicles were in the anagen phase. The model group mice showed significant miniaturization of hair follicles, a smaller number of follicles, follicle atrophy, lighter hair shaft pigmentation, and most follicles were in the telogen phase. The DUT-NS group and the DUT-NS-DMNs group showed a greater number of hair follicles, less significant miniaturization, darker hair shaft pigmentation, and most follicles in the anagen phase. Their effects even exceeded those of the positive drug control group, indicating that DUT-NS-DMNs and DUT-NS can inhibit hair follicle miniaturization in androgenetic alopecia model mice and promote the transition of mouse hair from the telogen phase to the anagen phase.

Claims

1. A soluble microneedle of a loaded tahistamine nanosuspension, characterized in that: It is prepared from dutasteride nanosuspension and DMN matrix material; The described dutasteride nanosuspension contains 1 mg / mL dutasteride, 0.5% w / v stabilizer, and the remainder is organic solvent. The organic solvent is methanol; the stabilizer is PVA1788. The DMNs matrix material is PVP K30-HA, the molecular weight of HA is 10w, and the ratio of PVP K30 to HA is 1:

1. The dutasteride nanosuspension is prepared by an antisolvent precipitation method, comprising the following steps: a. Dissolve dutasteride powder in an organic solvent; b. Under magnetic stirring, the organic solvent of the drug is rapidly injected into the aqueous solution containing the stabilizer using a syringe. The organic solvent is evaporated and the solution is homogenized under high pressure to obtain a nano-suspension. The method for producing soluble microneedles from the loaded tartrazine nanosuspension includes the following steps: a. Take two matrix materials, PVP K30 and HA, and HA powder with a molecular weight of 10w, mix them thoroughly in a 1:1 ratio, add the dutasteride nano suspension prepared above, let stand for 2 hours to fully dissolve it and remove the air bubbles, and then obtain the polymer solution. b. Pour the polymer solution quantitatively into the mold, and use the vacuum method to repeatedly evacuate the mold needle body part so that the solution completely fills the mold. Then put it in a 30℃ oven to dry for 6 hours. c. Demolding: Remove the mold and use tweezers to peel off the microneedles on the mold.

2. The soluble microneedles of the loaded tartrazine nanosuspension according to claim 1, characterized in that: In the preparation method of dutasteride nanosuspension, step b involves a homogenization pressure of 1000 bar and a homogenization time of 15 min.

3. Use of the soluble microneedles of the loaded tartrazine nanosuspension according to claim 1 or 2 in the preparation of a medicament for treating androgenetic alopecia.

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