Soluble microneedles containing cannabidiol suspension and method for preparing same

Abstract

To provide a nanonization method for cannabidiol, a nanosized cannabidiol suspension prepared by the same, and applications therefor.SOLUTION: A nanonization method for cannabidiol includes following steps: the cannabidiol is dissolved in a good solvent to obtain a cannabidiol-good solvent solution; and the cannabidiol-good solvent solution is added to an aqueous solution of a stabilizer, followed by ultrasonic treatment and then rotary evaporation to remove the good solvent, resulting in a nanosized cannabidiol suspension. The stabilizer includes one or more selected from the group consisting of poloxamer, polysorbate, polyoxyethylene alkyl ether, polyvinyl pyrrolidone, hydroxypropyl methyl cellulose and chitosan. Nanonization technology for poorly soluble drugs reduces the particle size of the cannabidiol to produce the nanosized cannabidiol suspension. In the nanosized cannabidiol suspension, nanosized cannabidiol has a high solid content. The method achieves the solubilization of the cannabidiol.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technical field of nano-cannabidiol, more particularly to a method for nano-cannabidiol, a nano-cannabidiol suspension prepared thereby, and its applications. [Background technology]

[0002] Cannabidiol is the most abundant cannabinoid in industrial hemp. It is non-psychoactive and essentially free of toxicity and side effects. Cannabidiol has attracted significant attention from the scientific community due to its therapeutic potential. Research has shown that cannabidiol has anti-inflammatory, anti-necrotic, and antioxidant properties, making it suitable for use in patients with multiple sclerosis, Alzheimer's disease, epilepsy, and Parkinson's disease. Currently, two FDA-approved cannabidiol products are available on the market: Epidiolex® (a pure CBD oral solution) and Sativex® (a CBD and Δ-9 THC oral mucosal spray). However, due to cannabidiol's low water solubility, erratic absorption in the gastrointestinal system, and the first-pass effect, its oral bioavailability is approximately 6%. Furthermore, cannabidiol's extreme lipophilicity (logP: 5.79) makes it prone to retention in the stratum corneum of the skin, posing challenges for its transport into deeper layers of the skin. Therefore, passive diffusion transdermal systems make it difficult to achieve circulation of cannabidiol in the body.

[0003] Nanoparticle size reduction is defined as a pharmaceutical process that involves reducing the particle size of active pharmaceutical ingredients to the nanosize range. This means achieving particle sizes in the submicron range, i.e., <1 μm. According to the Neuble-Wheaton equation, as the particle size of a drug decreases, its surface area increases, leading to a proportional increase in dissolution rate and improved absorption of poorly soluble drugs. In recent years, to improve the solubility and bioavailability of asahiniphenol, researchers have developed various nanoparticle methods for asahiniphenol, such as oral self-emulsifying systems, nanoliposomes, and nanomicelles. However, these methods tend to have limited solubilization of asahiniphenol and can sometimes result in system instability.

[0004] Microneedles are an active skin penetration enhancement technology. Microneedles have needle-like structures, typically several hundred microns long, that create micron-sized pores in the skin, enhancing drug delivery. They do not stimulate pain-related nerves, increasing patient compliance and reducing pain.

[0005] Due to the poor water solubility and low oral bioavailability of cannabidiol, and the limited and unstable solubilization amount of conventional technologies, it is necessary to develop high-dose cannabidiol nano-technology, and combine it with a micro-injectable dosage form to improve the storage stability and skin penetration rate of cannabidiol, reduce the administration frequency, and improve bioavailability and patient convenience. Summary of the Invention [Problem to be solved by the invention]

[0006] Based on the above problems, the object of the present invention is to provide a method for nanoparticle-forming cannabidiol, a nanoparticle-formed cannabidiol suspension prepared thereby, and its applications. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: In one aspect, the method for nanoparticleization of cannabidiol provided by the present invention comprises: dissolving cannabidiol in a good solvent to obtain a cannabidiol-good solvent solution; adding the cannabidiol-good solvent solution into an aqueous solution of a stabilizer, and then ultrasonicating and removing the good solvent by rotary evaporation to obtain a nano-sized cannabidiol suspension; Wherein the stabilizer is one or more selected from poloxamer, polysorbate, polyoxyethylene alkyl ether, polyvinylpyrrolidone, polyoxyethylene alkyl ether and chitosan, the resulting nano-sized cannabidiol nanosuspension has a high concentration of nano-sized cannabidiol, a high drug loading rate and good control of the particle size of nano-sized cannabidiol in the suspension.

[0008] Furthermore, the polyoxyethylene alkyl ether is selected from polyoxyethylene (20) cetyl ether (Brij 58) or polyoxyethylene (20) oleyl ether (Brij 98).

[0009] Furthermore, when the stabilizer is a mixture of several selected from poloxamer, polysorbate, polyoxyethylene alkyl ether, polyvinylpyrrolidone, hydroxypropyl methylcellulose, and chitosan, the mixing ratio is not limited and can be any ratio. For example, the stabilizer is selected from a mixture of polysorbate and hydroxypropyl methylcellulose, where the mixing ratio is 1:0.5 by weight, the stabilizer is selected from a mixture of polysorbate and polyvinylpyrrolidone, where the mixing ratio is 1:0.5 to 1:0.7 by weight, the stabilizer is selected from a mixture of polysorbate and carboxymethylchitosan, where the mixing ratio is 1:0.7 to 1:0.8 by weight, the stabilizer is selected from a mixture of poloxamer and polyvinylpyrrolidone, where the mixing ratio is 1:0.4 by weight, etc.

[0010] Further, the mass ratio of the cannabidiol to the stabilizer is 1:0.1 to 1:10. In some more specific examples, the mass ratio of the cannabidiol to the stabilizer is 1:0.1 to 1:5, 1:0.1 to 1:3, 1:0.1 to 1:2, 1:0.1 to 1:1.2, 1:0.1 to 1:0.8, 1:0.1 to 1:0.6, 1:0.1 to 1:0.5, 1:0.3 to 1:5, 1:0.3 to 1:3, 1:0.3 to 1:2, 1:0.3 to 1: The ratios include, but are not limited to, 1:1.2, 1:0.3 to 1:0.8, 1:0.3 to 1:0.6, 1:0.3 to 1:0.5, 1:0.5 to 1:5, 1:0.5 to 1:3, 1:0.5 to 1:2, 1:0.5 to 1:1.2, 1:0.5 to 1:0.8, 1:0.5 to 1:0.6, 1:0.3, 1:0.5:1:0.6, 1:0.8, 1:1.2, etc. In this case, the concentration of nano-sized cannabidiol in the obtained nano-sized cannabidiol nanosuspension is high, the drug loading rate is high, and the particle size of the nano-sized cannabidiol in the suspension can be well controlled.

[0011] Furthermore, the cannabidiol concentration in the cannabidiol-good solvent solution is 20 to 500 mg / mL. In some more specific examples, the cannabidiol concentration in the cannabidiol-good solvent solution is 25 to 500 mg / mL, 25 to 400 mg / mL, 25 to 300 mg / mL, 25 to 200 mg / mL, 25 to 150 mg / mL, 25 to 100 mg / mL, 100 to 500 mg / mL, 100 to 400 mg / mL, 100 to 300 mg / mL, 100 to 200 mg / mL, 100 to 150 mg / mL, 150 to Including, but not limited to, 500mg / mL, 150-400mg / mL, 150-300mg / mL, 150-200mg / mL, 200-500mg / mL, 200-400mg / mL, 200-300mg / mL, 300-500mg / mL, 300-400mg / mL, 25mg / mL, 100mg / mL, 150mg / mL, 200mg / mL, 300mg / mL, 400mg / mL, 500mg / mL, etc.

[0012] Furthermore, the good solvent is one or more selected from ethanol, isopropanol, propylene glycol, ethyl acetate, dimethyl sulfoxide, dichloroethane, and polyethylene glycol.

[0013] Furthermore, the concentration of the stabilizer in the aqueous solution of the stabilizer is 10 to 100 mg / mL. In some more specific examples, the concentration of the stabilizer in the aqueous solution of the stabilizer includes, but is not limited to, 20 to 50 mg / mL, 20 to 30 mg / mL, 30 to 50 mg / mL, 20 mg / mL, 30 mg / mL, etc.

[0014] Further, the volume ratio of the good solvent to water is 1:1 to 1:10. In some more specific examples, the volume ratio of the good solvent to water includes, but is not limited to, 1:1 to 1:7, 1:1 to 1:5, 1:1 to 1:5, 1:1 to 1:3, 1:1 to 1:2, 1:2 to 1:7, 1:2 to 1:5, 1:2 to 1:5, 1:2 to 1:3, 1:3 to 1:7, 1:3 to 1:5, 1:3 to 1:5, 1:1, 1:2, 1:3, 1:4:1.5, 1:7, 1:10, etc.

[0015] Furthermore, the power of the ultrasonic waves is 25 to 75 W, and the ultrasonic wave duration is 5 to 30 minutes.

[0016] Furthermore, in the nano-sized cannabidiol suspension, the concentration of the nano-sized cannabidiol is 10 to 100 mg / mL, and the particle size is 50 to 1000 nm.

[0017] In a further aspect, the present invention provides a nanoized cannabidiol suspension, which is prepared by the above method.

[0018] In a further aspect, the present invention provides soluble microneedles prepared from raw materials containing the drug components and excipients of the nano-sized cannabidiol suspension.

[0019] Furthermore, the content of nano-sized cannabidiol in the soluble microneedles is 1.5 to 25 wt %.

[0020] Furthermore, the excipient is one or more selected from polyvinyl alcohol, polyvinylpyrrolidone, hyaluronic acid, sodium carboxymethyl cellulose, and hydroxyethyl cellulose.

[0021] Furthermore, the raw material further includes a porogen, the function of which is to promote needle tip dissolution.

[0022] In addition, the porogen helps the water molecules in the fur to enter the needle matrix and regulate the drug release rate, and the porogen can include, but is not limited to, one or more selected from trehalose, maltose, sucrose, and magnesium chloride.

[0023] Furthermore, the soluble microneedles may be monolithic or layered. When the soluble microneedles are layered, the drug component of the nano-sized cannabidiol suspension is located at the needle tip.

[0024] Furthermore, the soluble microneedles are coated microneedles.

[0025] In a further aspect, the method for preparing the soluble microneedles provided by the present invention comprises: mixing the nano-sized cannabidiol-containing drug component and excipients to obtain an aqueous solution; placing the aqueous solution in a microneedle mold or a microneedle tip mold and drying to obtain the microneedles or soluble microneedle tips.

[0026] Furthermore, when the soluble material is an integral needle, the preparation method thereof includes: mixing the nano-sized cannabidiol-containing drug component and excipients to obtain an aqueous solution; placing the aqueous solution in a microneedle mold and drying to obtain the microneedle; When the soluble microneedles are layered needles, the preparation method thereof includes: Mixing the nano-sized cannabidiol suspension-containing drug ingredients and excipients to obtain a needle tip aqueous solution; placing the needle tip aqueous solution in a microneedle mold and drying; The method further includes the steps of dropping a base liquid, evacuating the mold under negative pressure, and drying to obtain the microneedles.

[0027] Furthermore, in the aqueous solution, the solid content of the excipient is 10 to 25%, and the solid content of the porogen is 0.03 to 1%. [Effects of the Invention]

[0028] The method for nano-synthesis of cannabidiol provided by the present invention uses a poorly soluble drug nano-synthesis technology to reduce the particle size of the poorly soluble drug cannabidiol to obtain a cannabidiol nano-suspension, and the suspension has a high solid content of nano-sized cannabidiol, so that the method achieves the solubilization effect of cannabidiol. The method for preparing soluble microneedles provided by the present invention involves adding an excipient to a cannabidiol nano-suspension and then preparing microneedles, thereby eliminating the traditional method for solidifying nano-sized poorly soluble drug suspensions, improving the stability of the nano-sized drug, and utilizing the drug targeting ability of the microneedles to complete the transdermal administration of poorly soluble drugs, thereby improving the skin penetration rate of cannabidiol, reducing the administration frequency compared to oral drugs, and improving bioavailability. [Brief explanation of the drawings]

[0029] Specific embodiments of the present invention will be described in more detail below with reference to the drawings. [Figure 1] FIG. 1 shows the particle size distribution diagram of the cannabidiol nanosuspension prepared in Example 10 of the present invention. [Figure 2] 1 shows an optical microscope photograph of the microneedle prepared in Example 30 of the present invention. [Figure 3]1 shows the results of trypan blue staining after the microneedles prepared in Example 30 of the present invention are pierced into ex vivo pig skin. [Figure 4] 1 shows a graph of the change in dissolution height after the microneedles prepared in Example 39 of the present invention are pierced into ex vivo pig skin. [Figure 5] FIG. 1 shows the in vitro drug release curve of the microneedles prepared in Example 39 of the present invention. [Figure 6] 1 shows a curve diagram of the cumulative transdermal permeation amount of the microneedles prepared in Example 39 of the present invention. [Figure 7] 1 shows the results of an experiment on the drug metabolism kinetics in rats using microneedles prepared in Example 39 of the present invention. [Figure 8] 1 shows a topographical image of a split-layer microneedle prepared in Example 47 of the present invention under a fluorescence microscope. DETAILED DESCRIPTION OF THE INVENTION

[0030] In order to more clearly explain the present application, the present invention will be further described below in conjunction with preferred embodiments and drawings. In the drawings, similar components are designated by the same reference numerals. Those skilled in the art will understand that the contents specifically described below are illustrative and not limiting, and should not thereby limit the protection scope of the present invention.

[0031] Example 1 Preparation and Evaluation of Cannabidiol Nanosuspensions: Prepare the cannabidiol suspension according to the following steps: Preparation of cannabidiol nanosuspension: 0.20 g of cannabidiol was dissolved in 1 mL of absolute ethanol to form the organic phase, and 2% (w / w) aqueous polysorbate solution was used as the aqueous phase. The volume ratio of the two mixtures was controlled to 1:5, and the organic phase was gradually added dropwise to the aqueous phase and ultrasonicated at 45 W for 10 min. The resulting mixture was spin-evaporated to remove the organic solvent, yielding a polysorbate-cannabidiol nanosuspension. Content test: The solution of Example 1 was diluted 100 times with a mobile phase of acetonitrile:water=75:25, and a content test was carried out by high performance liquid chromatography to calculate the drug loading rate. Drug loading rate = actual measured cannabidiol concentration / theoretical obtained cannabidiol concentration × 100% Theoretical cannabidiol concentration = cannabidiol added / aqueous phase volume. Particle size test: The sample prepared in Example 1 was diluted 100 times with ultrapure water, and then the particle size was measured using a nanoparticle size potential analyzer (Mastersizer 2000). Tests showed that the concentration of cannabidiol in the nanosuspension was measured to be 24.7 mg / mL, the drug loading rate was 61.8%, and the particle size of the nano-sized cannabidiol was approximately 284 nm.

[0032] (Comparative Example 1) Prepare cannabidiol nanosuspension by stirring: 0.20 g of cannabidiol was dissolved in 1 mL of absolute ethanol to form the organic phase, and 2% (w / w) aqueous polysorbate solution was used as the aqueous phase. The volume ratio of the two mixtures was controlled to 1:5, and the organic phase was gradually added dropwise to the aqueous phase under magnetic stirring. The resulting mixture was spin-evaporated to remove the organic solvent, yielding a polysorbate-cannabidiol nanosuspension. The test measured a cannabidiol concentration of 17.0 mg / mL, a drug loading rate of 42.5%, and particle size of approximately 93 nm.

[0033] (Comparative Example 2) Prepare cannabidiol nanoemulsion by stirring: 0.20 g of cannabidiol was added directly to 5 mL of 2% (w / w) aqueous polysorbate solution, and after 24 hours of magnetic stirring, an emulsion containing cannabidiol was finally obtained. The test measured a cannabidiol concentration of 10.1 mg / mL, a drug loading rate of 25.2%, and a cannabidiol particle size of approximately 55 nm.

[0034] (Examples 2 to 9) The preparation method is the same as in Example 1, and the parameters of each component in Examples 2 to 9 are as shown in Table 1.

[0035] [Table 1]

[0036] As is clear from the above results, the ultrasonic anti-solvent precipitation method in the examples has a better solubilizing effect on cannabidiol than the methods used in Comparative Examples 1 and 2.

[0037] Example 10 The preparation of cannabidiol nanosuspension comprises the following steps: 0.30 g of cannabidiol was dissolved in 1 mL of absolute ethanol to form the organic phase, and 3% (w / w) aqueous polysorbate solution was used as the aqueous phase. The volume ratio of the two mixtures was controlled to 1:5, and the organic phase was gradually added dropwise to the aqueous phase. The mixture was then ultrasonicated at 45 W for 10 min. The resulting mixture was spin-evaporated to remove the organic solvent, yielding a cannabidiol nanosuspension. Testing revealed that the final suspension had a cannabidiol concentration of 46.4 mg / mL and a drug loading rate of 77.33%. As shown in Figure 1, the particle size of cannabidiol in the suspension obtained in Example 10 was approximately 128 nm.

[0038] (Examples 11 to 24, Comparative Examples 3 to 6) Different stabilizers were selected to prepare cannabidiol nanosuspensions, the method was the same as in Example 1, and the formulation was as shown in Table 2 below.

[0039] [Table 2]

[0040] As can be seen from the above results, the stabilizers used in Comparative Examples 3 to 6 were unable to prepare cannabidiol nanosuspensions well and failed to achieve ideal solubilizing and stabilizing effects. The particle size of the cannabidiol nanosuspensions prepared using the stabilizer formulations in Examples 12 to 24 was between 50 and 1000 nm, and the concentration was between 10 and 60 mg / mL.

[0041] (Examples 25 to 29) See Example 10, cannabidiol nanosuspensions were prepared using different ultrasonic powers and times, and the formulations and results are shown in Table 3 below.

[0042] [Table 3]

[0043] As is clear from the above results, Examples 26 to 29 can all satisfy the target concentration and nano-size requirements when the ultrasonic power is 25 to 75 W and the ultrasonic time is in the range of 5 to 30 minutes.

[0044] Example 30 A method for preparing integrated microneedles carrying nano-sized cannabis biphenols includes the following steps: (1) Preparation of microneedle solution: 4.0 g of the cannabidiol nanosuspension prepared in Example 10 above was taken, and 1.0 g of the excipient polyvinylpyrrolidone was added thereto, and the two were mixed uniformly and then centrifuged to remove air bubbles. (2) Preparation of microneedles: 60 μL of the microneedle solution was added to the PDMS mold, and the mold was vacuumed for 5 minutes and dried at room temperature to obtain the microneedles. (3) Inspection of each parameter of the microneedle Microneedle integrity: The overall shape of the microneedle was observed under a stereomicroscope to determine whether it could be completely released from the mold and whether the needle tip shape was intact. The topography of the microneedle in Example 30 under an optical microscope is shown in Figure 2. The microneedle array consisted of 144 (12 x 12) conical arrays, with an area of ​​0.56 cm and a needle height of 500 μm. Puncture ability of microneedles: Using the ear skin of a young animal, cut out an appropriate area, place the tip of the microneedle flat downward, and apply a needle feed pressure of 20N from the back of the microneedle, continue to press for 10 seconds, and after the pressure is completed, remove the microneedle from the skin, drop trypan blue dye solution onto the skin at the needle application site, stain for 5 minutes, then wash the skin, if a neat and tidy array of colored pinholes is observed, it has puncture ability. The puncture result of Example 30 is shown in Figure 3, where pinholes are clearly visible to the naked eye, and when a piece of the skin is removed, the pinhole array becomes neater and more complete.

[0045] (Examples 31 to 34 and Comparative Examples 7 to 11) Comparative Examples 7 to 11 and Examples 31 to 34 list monolithic dissolving microneedles prepared using excipients that the inventors have tried. The excipients in the comparative examples include polyglutamic acid (γ-PGA), chondroitin sulfate (CS), dextran (DEX), hypromellose (HPMC), and hydroxypropyl cellulose (HHPC). The excipients in the examples include polyvinyl alcohol (PVA), hyaluronic acid (HA), hydroxyethyl cellulose (EC), and sodium carboxymethyl cellulose (CMC). All were prepared according to the method of Example 30, using the weight percentages of the materials shown in Table 1.

[0046] The integrity, puncture ability and needle body color of the microneedle were detected in the same manner as in Example 30, and the detection results are shown in Table 4.

[0047] [Table 4]

[0048] As can be seen from Table 4, Comparative Examples 7 to 11 used different microneedle substrate materials, of which γ-PGA, CS, and HPMC caused yellowing when needles were formed, and the DEX microneedles became brittle and were easily broken when the needle tips peeled off, all of which did not meet the appearance requirements of the formulation. When HHPC was used as the microneedle material, the microneedles had no puncture ability and did not meet the usage requirements of the microneedle formulation. When PVA, PVP, CMC, HA, and EC were used as the microneedle material, the appearance and puncture ability both met the appearance and usage requirements of the formulation.

[0049] (Examples 35 to 36 and Comparative Example 12) Cannabidiol percentage range in soluble microneedles: The nanocannabidiol concentration range was 10-100 mg / mL, which dictated the upper and lower limits of the drug loading rate for the microneedles. A cannabidiol concentration of 10 mg / mL was selected to determine the lower limit of the drug loading rate for the microneedles, and a cannabidiol concentration of 100 mg / mL was selected to determine the upper limit of the drug loading rate. Based on the preparation method of Example 30, microneedles were prepared with the weight percentages of materials shown in Table 5, and the needle properties and drug loading rate of the microneedles were investigated. Microneedle content test: One microneedle sample was placed in a centrifuge tube, 3 mL of mobile phase (acetonitrile:water = 75:25) was added, and the tube was shaken with a vortex meter for 120 minutes to extract cannabidiol, which was then filtered into a liquid vial using a 0.22 μm filter membrane and subjected to HPLC testing. Percentage of cannabidiol in microneedles = cannabidiol content / total solid content in microneedles × 100%.

[0050] [Table 5]

[0051] The drug loading rate of the microneedles is related to the amount of cannabidiol added and the mass ratio of the excipients. Considering the lower limit of the drug loading rate, the mass ratio of the excipients should be as high as possible. Example 35 selected a mass fraction of 70% excipients, and the resulting microneedles had good needle formability and a drug loading rate of 1.5%. When preparing an excipient with a higher mass ratio, the drug loading rate of the microneedles relative to cannabidiol should be lower. The microneedles prepared in Example 36 had perfect needle tips and excellent toughness. However, in Comparative Example 12, when the proportion of PVA was reduced, the microneedles' toughness was insufficient and the needle tips were broken. Therefore, it is preferable to limit the drug loading rate of cannabidiol in the microneedles to within 25%.

[0052] (Examples 37 to 42 and Comparative Example 13) Different porogens are added to prepare monolithic microneedles carrying nanonized cannabidiol: (1) Preparation of microneedle solution: To 5.0 g of the cannabidiol nanosuspension prepared in Example 10, 0.70 g of hyaluronic acid and 0.30 g of PVP were added as excipients. Then, porogen was added according to the formula shown in Table 6, and the mixture was mixed uniformly and centrifuged to remove air bubbles. (2) Preparation of microneedles: 60 μL of the microneedle solution was added to the PDMS mold, and the mold was vacuumed for 5 minutes and dried at room temperature to obtain the microneedles. (3) Microneedle solubility experiment: The microneedles were attached to the in vitro pig skin for 30 seconds, and a pressure-sensitive adhesive was attached to the base layer and maintained for a certain period of time. To characterize the transdermal dissolution of the microneedles, the remaining microneedles were placed under a fluorescence microscope and the change in microneedle height was studied.

[0053] Figure 4 shows the results of the solubility test of the microneedles prepared in Example 39. As can be seen, the dissolution rate of the microneedles is fast, with the needle tips almost completely dissolved within 10 minutes, allowing the microneedles to quickly penetrate into the skin and release the drug.

[0054] [Table 6]

[0055] As can be seen from the above results, the addition of porogen improves the dissolution rate of the microneedles in the skin, which is beneficial for the release of the drug.

[0056] Example 43 Accelerated Stability Content Testing of Cannabidiol Microneedles: The microneedle patch in Example 39 was packaged in a blister and aluminum plastic bag and stored at 50°C for 3 months. The cannabidiol content of the integrated microneedles was measured using high-performance liquid chromatography on day 0 and 3 months. The microneedle content measured after the liquid phase test was 99.3%. After the cannabidiol preparation into the microneedles, good drug stability was maintained, and the microneedle dosage form was easy to store and transport.

[0057] Example 44 Measurement of in vitro drug release of cannabidiol microneedles: The microneedles prepared in the examples were collected. One microneedle was taken, placed in a dialysis bag, and dispersed in 200 μL of receptor solution. The dialysis bag was then tightly sealed and suspended in a stoppered Erlenmeyer flask containing 5 mL of receptor solution. The receptor solution was a 1% polysorbate 80-PBS solution. A magnet was attached to the Erlenmeyer flask, the magnetic stirring speed was 280 rpm, and the flask was placed in a thermostatic water bath at 37 ± 0.2 °C. The entire sample in the Erlenmeyer flask was periodically removed and replenished with the same volume of release medium. The removed solution was filtered through a 0.45 μm filter membrane and transferred to a liquid vial. The cannabidiol concentration in the sample was determined by high-performance liquid chromatography.

[0058] Figure 5 shows the in vitro drug release rate curve of the microneedles obtained in Example 39. The microneedles of Example 39 rapidly released the drug starting 2 hours before the drug release, achieving a release rate of 71.25±1.19%. After 8 hours, the cumulative release curve became smooth, indicating complete release.

[0059] Example 45 In vivo skin kinetics of cannabidiol microneedles in rats A male adult SD rat (weighing approximately 250 g) was immobilized and its abdominal skin was depilated using depilatory cream. The resulting microneedles were then pierced perpendicularly into the skin and held in place for 2, 4, 8, 12, and 24 hours. The microneedle array was then removed, and the skin was washed twice with a cotton ball dipped in medical alcohol. The array, along with the removed patch, was then placed in a 5 mL centrifuge tube and stored. The remaining microneedle content was extracted and analyzed by high-performance liquid chromatography.

[0060] Figure 6 shows the cumulative permeation curve of the microneedle transdermal dose after the in vivo skin dynamics experiment on rats using the microneedles obtained in Example 39. It can be seen that the permeation rate of the microneedles reaches 1246.90±404.07 μg / cm² within 2 hours, and the permeation rate slows down over time. Example 46

[0061] In vivo drug metabolism and kinetics of cannabidiol microneedles in rats Male adult SD rats (approximately 250 g in weight) were immobilized and their abdominal skin was depilated using a depilatory cream. The resulting microneedles were inserted perpendicularly into the skin, and the microneedles were removed 24 hours after administration. Blood samples were collected from the rats' tail veins at predetermined time points before and after administration. The samples were placed in heparinized tubes and centrifuged at 5,000 rpm for 10 minutes at 4°C. The upper layer of plasma was collected and stored at 80°C. After plasma processing, a content test was performed.

[0062] Figure 7 shows the experimental results of the in vivo drug metabolism kinetics of microneedles in rats obtained in Example 39. Microneedle administration was able to maintain blood drug concentrations for 3 days, while the intragastric administration group could only maintain them for 2 days, with an area under the curve 12 times that of the intragastric administration group. The cannabidiol microneedle dosage form designed in this invention not only improves the bioavailability of cannabidiol, but also achieves a consistent sustained-release effect, reducing the administration frequency and improving patient compliance.

[0063] (Comparative Example 14) Preparation of cannabidiol-integrated microneedles dissolved in organic solvents, heat resistance evaluation, and in vitro release evaluation: A cannabidiol base solution containing 10% (w / w) polylactic-co-glycolic acid (PLGA), 10% (w / w) PVP, and 4% (w / w) cannabidiol was prepared using N,N-dimethylacetamide (DMA) as a solvent. After uniformly mixing, it was used as the needle tip injection molding solution. 50 μL of the microneedle solution was placed in a PDMS mold, vacuumed for 5 minutes, and heated at 50°C for 3 hours. Heat resistance evaluation: The microneedles obtained in Comparative Example 14 were sealed and packaged, and then placed in an incubator at 60°C for 10 days. After 10 days, they were removed and the side view of the microneedles was observed under an optical microscope to observe the integrity and color of the microneedles' topography. Measurement of in vitro drug release: The procedure was the same as in Example 44.

[0064] (Comparative Examples 15 to 18) The preparation method was the same as in Comparative Example 14, using polylactic acid (PLA), PVA, PVP, and HPMC materials, and the organic solvents used for dissolution were DMA, N,N-dimethylformamide (DMF), and N-methylpyrrolidone (NMP). The heating process involved heating and natural drying, and finally, an in vitro release evaluation was performed. The components and experimental results for Comparative Examples 15 to 18 are shown in Table 7.

[0065] [Table 7]

[0066] When cannabidiol-integrated microneedle systems dissolved in organic solvents use PLGA, PLA, PVA, PVP, and HPMC materials, they are difficult to release outside the body and are prone to discoloration under high temperature conditions, so it is inappropriate to directly dissolve cannabidiol in an organic solvent to prepare integrated microneedles.

[0067] Example 47 Nano-sized cannabidiol hierarchical dissolving microneedles Prepare nanoized cannabidiol hierarchical dissolving microneedles according to the following steps: (1) Preparation of layered microneedle substrate solution: Preparation of needle tip solution: Take 1.0 g of the cannabidiol nanosuspension (containing the fluorescent substance coumarin 6) from Example 10, add 0.14 g of HA, 0.06 g of PVP, and 0.01 g of trehalose in that order, stir evenly, and centrifuge to prepare for use. Preparation of the primer solution: 10.0 g of ultrapure water was weighed into a centrifuge tube, and 10.0 g of PVA weighed into the centrifuge tube was added. The tube was heated in an oven at 80°C to swell the mixture, and the mixture was stirred every half hour until it was completely dissolved. Air bubbles were removed by centrifugation, and a primer solution with a PVA solid content of 50% was obtained. (2) Preparation of microneedles: 5 μL of each liquid was transferred from the liquid addition gun and dropped onto the PDMS microneedle. After vacuuming for 5 minutes, the tip of the microneedle was allowed to dry naturally at room temperature for 30 minutes. Next, 50 μL of the primer liquid was dropped onto each liquid. The mold was depressurized and vacuumed for 10 minutes, and the microneedle was allowed to dry naturally at room temperature and then released from the mold. (3) Observation of microneedle topography: As shown in Figure 8, the tip height of the fabricated fractional microneedle was observed under a fluorescence microscope and was found to be approximately 300 μm. (4) Microneedle solubility experiment: (According to the steps of Example 37, it was observed under a microscope that the drug-loaded needle tip was completely dissolved within 5 minutes after being placed on the layered needle. (5) In vitro drug release measurement: (According to the steps of Example 44, the layered needle release rate measurement was carried out. The layered needle could reach a cumulative release rate of more than 50% within the first 30 minutes.

[0068] Example 48 Nano-sized cannabidiol coated microneedles Prepare coated microneedles of nanoized cannabidiol according to the following steps: (1) An appropriate amount of PLGA was placed in a microneedle-integrated matrix mold, a vacuum was drawn below the mold, and the mold was heated to a high temperature of 190°C for 5 minutes. The polymer material was pressed to flatten it, and after cooling and demolding, a polylactic acid-integrated microneedle base was obtained. (2) Drug solution: (Take 1.0 g of the cannabidiol nanosuspension in Example 10, add 0.1 g of PVP, 0.1 g of 50% (w / w) PVA solution, and 0.02 g of trehalose, sequentially. Stir evenly and centrifuge to prepare for use. (3) The drug solution prepared above was placed in a drug-loaded pool 300 μm in height. The microneedle base with the PLGA attached was then dropped into the drug-loaded pool with the needle tip facing downwards, after which the microneedle was left standing for 3 minutes to dry the coating layer. This dip drying process was repeated four times. Finally, coated microneedles carrying nanosized cannabidiol were obtained. (4) Microneedle solubility experiment: According to the steps of Example 37, observation was made under a microscope and it was observed that the drug-carrying needle tip of the coated needle was almost completely dissolved when it was left in place for 30 minutes. (5) In vitro drug release measurement: The release rate of the coated needles was measured according to the steps of Example 44. The coated needles could reach a cumulative release rate of more than 50% within the previous 8 hours.

[0069] The above examples of the present invention are merely illustrative to clearly explain the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art may make other different forms of changes or variations in addition to the above description. It is not possible to cover all embodiments here, and obvious changes or variations due to the technical solutions of the present invention are included in the protection scope of the present invention.

Claims

1. A method for preparing soluble microneedles, comprising: The soluble microneedles are prepared from raw materials containing drug components and excipients of a nano-sized cannabidiol suspension, and the preparation of the nano-sized cannabidiol suspension includes: Dissolving cannabidiol in a good solvent, which is one or more selected from ethanol, isopropanol, propylene glycol, ethyl acetate, dimethyl sulfoxide, dichloroethane, and polyethylene glycol, to obtain a cannabidiol-good solvent solution; Adding the cannabidiol-good solvent solution to an aqueous solution of a stabilizer, and then ultrasonically treating it, followed by removing the good solvent by rotary evaporation to obtain a nano-sized cannabidiol suspension; mixing the nano-sized cannabidiol-containing drug component and excipients to obtain an aqueous solution; placing the aqueous solution in a microneedle mold or a microneedle tip mold and drying to obtain the microneedles or soluble microneedle tips; The power of the ultrasonic wave is 25 to 75 W, and the duration of the ultrasonic wave is 5 to 30 minutes; the stabilizer is one or more selected from the group consisting of poloxamer, polysorbate, polyoxyethylene alkyl ether, polyvinylpyrrolidone, hydroxypropyl methylcellulose, and carboxymethyl chitosan; The mass ratio of the cannabidiol to the stabilizer is 1:0.3 to 1:5; the excipient is one selected from a mixture of polyvinylpyrrolidone and hyaluronic acid, a mixture of polyvinyl alcohol and polyvinylpyrrolidone, sodium carboxymethyl cellulose, and hydroxyethyl cellulose; In the cannabidiol-good solvent solution, the cannabidiol concentration is 20 to 500 mg / mL; The mass fraction of the excipient is 70%; The drug loading rate of the microneedles for cannabidiol is limited to 25% or less; A method for preparing soluble microneedles, characterized in that the content of the nano-sized cannabidiol in the soluble microneedles is 1.5 to 25 wt%.

2. The method for preparing soluble microneedles according to claim 1, characterized in that the concentration of the stabilizer in the aqueous solution of the stabilizer is 10 to 100 mg / mL.

3. The method for preparing soluble microneedles according to claim 1, characterized in that the volume ratio of the good solvent to water is 1:1 to 1:

10.

4. The method for preparing soluble microneedles according to claim 1, characterized in that in the nano-sized cannabidiol suspension, the concentration of nano-sized cannabidiol is 10 to 100 mg / mL and the particle size is 50 to 1000 nm.

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