Dexmedetomidine hydrochloride microneedle as well as preparation method and application thereof

Abstract

The invention relates to a dexmedetomidine hydrochloride microneedle which is prepared from a drug-loading needle body layer and a substrate layer, the volume ratio of the drug-loading needle body layer to the substrate layer is 1: 100-200, the drug-loading needle body layer is prepared from polyvinylpyrrolidone and dexmedetomidine hydrochloride according to the mass ratio of 1-15: 1, and the substrate layer is prepared from polyethylene glycol diacrylate through photo-crosslinking. The dexmedetomidine hydrochloride microneedle disclosed by the invention has the advantages that the dexmedetomidine hydrochloride microneedle takes effect quickly, is long in drug effect maintenance time, is non-irritant to skin, avoids infection risk, realizes percutaneous precise administration of dexmedetomidine hydrochloride, and remarkably improves bioavailability and medication safety and effectiveness of dexmedetomidine hydrochloride.

Description

Technical Field

[0001] The present invention relates to the field of medicine, and particularly to dexmedetomidine hydrochloride microneedles, a preparation method thereof, and an application thereof. Background Art

[0002] Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or a similar experience. Epidemiological survey results show that more than 30% of the global population suffers from chronic pain, and more than 35.9% of the population in China suffers from chronic pain.

[0003] Dexmedetomidine hydrochloride (DEX) is an α-2 adrenergic receptor agonist, which has the advantages of non-addiction, high safety, excellent sedative and analgesic capabilities, arousability, multi-modal sedation, etc., and has become an important tool for ICU and perioperative management. It is widely used for preoperative sedation, postoperative analgesia, anti-anxiety, etc. There are already injections of dexmedetomidine hydrochloride, Precedex TM (2 ml: 200 μg), sublingual film Igalmi TM (0.12 mg, 0.18 mg), and nasal spray Abemaciclib TM (1 ml: 500 μg) for preoperative sedation, analgesia, anti-anxiety, etc., but there are problems such as needle stick injuries, injection pain, and easy coughing during nasal spraying, resulting in poor compliance of patients, especially pediatric patients. Moreover, when the loading dose of dexmedetomidine hydrochloride in the body is ≥ 1.5 μg / kg or the infusion rate is ≥ 0.7 μg / (kg·h), patients are prone to side reactions such as hypotension and bradycardia, and show dose dependence. Severe arrhythmia side reactions such as sinus arrest, sinoatrial block, and atrioventricular block may even occur. Therefore, it is necessary to strictly monitor the side reactions related to the dosage of dexmedetomidine hydrochloride.

[0004] Transdermal drug delivery can enable the drug to effectively pass through the skin and be transported to local tissues or the systemic blood circulation to exert a therapeutic effect, significantly improving the convenience of clinical application of the drug. However, there are technical difficulties in transdermal drug delivery of water-soluble drugs. Dexmedetomidine hydrochloride belongs to water-soluble drugs, and its transdermal permeation rate is low. In the prior art, dexmedetomidine is mixed with propylene glycol and a stabilizer to prepare a dexmedetomidine patch with a relatively high permeability coefficient (0.35 mg / 6.6 cm 2 / patch), and the drug effect lasts for more than 72 hours, which is used to improve the sleep quality of perioperative patients, and has now completed clinical phase I.

[0005] Microneedles (MNs) have a microscopic structure with a high aspect ratio and puncture ability, and have the characteristics of being painless, minimally invasive, highly efficient, less invasive, directionally penetrating the stratum corneum and physiological barriers, increasing the contact area and depth with the wound surface, etc., and delivering drugs into the skin. Soluble microneedles are prepared from water-soluble polymer materials. After penetrating the skin stratum corneum and contacting the skin tissue fluid, they quickly dissolve, and the drug components contained in the needle body are released, enabling water-soluble drugs to penetrate the stratum corneum barrier, significantly increasing their transdermal penetration efficiency and bioavailability, achieving efficient penetration absorption and rapid onset of drugs in subcutaneous tissues and the human body, and being convenient for drug administration.

[0006] The preparation of microneedles includes microinjection molding, hot pressing molding, thermal stretching lithography, laser etching, etc., but there are limitations in the preparation of microneedle precision and complex structures. 3D printing technology is based on a digital model and manufactures solid objects by stacking materials layer by layer. Area projection 3D printing technology can simultaneously achieve high-resolution and large-format 3D printing, and is used for the manufacture of complex three-dimensional structures in frontier fields, widely used in precision medical devices, electronic components, microfluidics, materials, etc., and has achieved an optical precision of 2μm.

[0007] 3D printing technology (3D printing, 3DP) is an additive manufacturing and rapid prototyping technology. It is a manufacturing technology that constructs objects by printing materials layer by layer based on a three-dimensional model of computer-aided design (Computer Aided Design, CAD), including powder binding (Powder Binding, PB), fused deposition modeling (Fused Deposition Modeling, FDM), semi-solid extrusion (Semi Solid Extrusion, SSE), stereolithography (Stereolithography, SLA), etc. By selecting printing materials, optimizing process parameters and model structure design (such as size, shape, structure and dosage, etc.), the appearance, dosage and release characteristics of drugs can be precisely controlled, providing more accurate, effective and personalized therapeutic drugs for clinical use.

[0008] Existing dexmedetomidine hydrochloride microneedles use polyvinylpyrrolidone, hyaluronic acid, chitosan, etc. as the base layer, but there are the following defects: First, the drug is dispersed into the base layer, resulting in the drug dispersed into the base layer being difficult to be absorbed, causing drug waste and affecting the dosage accuracy of drug administration; Second, the drug release time in the body is short, increasing the drug side effects related to the dose dependence of dexmedetomidine hydrochloride (such as hypotension, nausea, bradycardia, tissue hypoxia, etc.); Third, the preparation time is long, the precision is low, and the yield rate is poor; Fourth, the mechanical strength of the microneedles is too soft, which is not conducive to inserting into the skin, and it is easy to cause uncomfortable adhesion on the skin when pressing the microneedles, affecting the patient's medication compliance; Fifth, the drug loading amount varies greatly between batches, and it is necessary to strictly monitor its dose-related side effects, etc. Therefore, how to select the drug-loaded needle body layer and base layer materials, improve the mechanical strength of the microneedles, and accurately control the drug dosage has become an urgent problem to be solved. Summary of the Invention

[0009] The purpose of the present invention is to provide a dexmedetomidine hydrochloride microneedle, which is made of a drug-loaded needle body layer and a base layer. Among them, the volume ratio of the drug-loaded needle body layer to the base layer is 1:100 - 200, and in the drug-loaded needle body layer, polyvinylpyrrolidone (Polyvinylpyrrolidone, PVP): dexmedetomidine hydrochloride is prepared according to a mass ratio of 1 - 15:1, and the base layer is prepared by photocrosslinking of polyethylene glycol diacrylate (Polyethylene Glycol Diacrylate, PEGDA).

[0010] In the preferred technical solution of the present invention, the volume ratio of the drug-loaded needle body layer to the base layer is 1:100 - 150.

[0011] In the preferred technical solution of the present invention, the mass ratio of polyvinylpyrrolidone to dexmedetomidine hydrochloride in the drug-loaded needle body layer is 2 - 10:1.

[0012] In the preferred technical solution of the present invention, the drug-loaded needle body layer is a quadrangular pyramid patch.

[0013] In the preferred technical solution of the present invention, the preparation of the drug-loaded needle body layer includes the following steps. Under stirring (100 - 200 rpm) conditions, in a polyvinylpyrrolidone solution with a concentration of 10 - 30%, dexmedetomidine hydrochloride is added according to a mass ratio of polyvinylpyrrolidone to dexmedetomidine hydrochloride of 1 - 15:1. The prepared mixed solution of polyvinylpyrrolidone and dexmedetomidine hydrochloride is injected into a polydimethylsiloxane female mold, vacuum degassed, and then dried to obtain.

[0014] In the preferred technical solution of the present invention, the concentration of dexmedetomidine hydrochloride is 1 - 7%, preferably any one of 3%, 5%, and 7%.

[0015] In a preferred technical solution of the present invention, the concentration of the polyvinylpyrrolidone is 15-20%.

[0016] In a preferred technical solution of the present invention, the prepared polyvinylpyrrolidone and dexmedetomidine hydrochloride mixed solution is injected into a polydimethylsiloxane female mold, after vacuum degassing and drying, the prepared polyvinylpyrrolidone and dexmedetomidine hydrochloride mixed solution is injected into the polydimethylsiloxane female mold again, after vacuum degassing and drying, it is obtained.

[0017] In a preferred technical solution of the present invention, the concentration of the dexmedetomidine hydrochloride is 1-2%, preferably any one of 1%, 1.5%, and 2%.

[0018] In a preferred technical solution of the present invention, the base layer is a square patch.

[0019] In a preferred technical solution of the present invention, the preparation of the base layer includes the following steps: under stirring (100-200 rpm) conditions, poly(ethylene glycol) diacrylate (PEGDA400): poly(ethylene glycol) diacrylate (PEGDA600) are mixed in a mass ratio of 1:1-5, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TMO) with a weight percentage concentration of 0.5% is added, and they are mixed for 0.5-1 h. The prepared poly(ethylene glycol) diacrylate solution (PEGDA) is injected into a polydimethylsiloxane female mold, and after ultraviolet curing, it is obtained.

[0020] In a preferred technical solution of the present invention, in the preparation of the base layer, the mass ratio of poly(ethylene glycol) diacrylate (PEGDA400): poly(ethylene glycol) diacrylate (PEGDA600) is 1:1-2.

[0021] In a preferred technical solution of the present invention, in any preparation of the drug-loaded needle layer and the base layer, the vacuum degassing conditions are -0.1 to -0.2 MPa for 2-10 min, preferably -0.1 MPa for 2 min.

[0022] In a preferred technical solution of the present invention, in any preparation of the drug-loaded needle layer and the base layer, the ultraviolet curing conditions are λ = 405 nm and the light intensity is 25 mW·cm -2 .

[0023] In a preferred technical solution of the present invention, in any preparation of the drug-loaded needle layer and the base layer, the drying temperature is 50°C - 100°C, preferably 60°C - 80°C.

[0024] In a preferred technical solution of the present invention, the preparation of the dexmedetomidine hydrochloride microneedles includes the following steps:

[0025] (1) Immerse the 3D printed master template in a polyvinyl alcohol solution with a concentration of 1 - 5% for 10h - 24h. After drying, fix it, then add defoamed polydimethylsiloxane. After curing, peel it off to obtain a polydimethylsiloxane negative mold.

[0026] (2) Under the condition of stirring (100 - 200 rpm), add dexmedetomidine hydrochloride to a polyvinylpyrrolidone solution with a concentration of 10 - 30% according to the mass ratio of polyvinylpyrrolidone:dexmedetomidine hydrochloride of 1 - 15:1. Inject the prepared mixed solution of polyvinylpyrrolidone and dexmedetomidine hydrochloride into the polydimethylsiloxane negative mold. After vacuum degassing, dry it to obtain the drug-loaded needle layer.

[0027] (3) Under the condition of stirring (100 - 200 rpm), mix polyethylene glycol diacrylate (PEGDA400):polyethylene glycol diacrylate (PEGDA600) according to the mass ratio of 1:1 - 5, add 2,4,6-trimethylbenzoyl-diphenylphosphine oxide with a weight percentage concentration of 0.5%, and mix for 0.5 - 1h. Inject the prepared polyethylene glycol diacrylate solution into the polydimethylsiloxane negative film. After ultraviolet curing, obtain the base layer.

[0028] (4) Demold to obtain the product.

[0029] In the preferred technical solution of the present invention, the microneedles are prepared by a method combining 3D printing and molding with a polydimethylsiloxane negative mold (polydimethylsiloxane, PDMS).

[0030] In the preferred technical solution of the present invention, the preparation of the polydimethylsiloxane negative mold includes the following steps: Immerse the 3D printed master template in a polyvinyl alcohol solution with a concentration of 1 - 5% for 10h - 24h. After drying, fix it, then add defoamed polydimethylsiloxane. After curing, peel it off to obtain the product.

[0031] In the preferred technical solution of the present invention, in the preparation of the polydimethylsiloxane negative mold, the concentration of the polyvinyl alcohol solution is 1 - 2%.

[0032] In the preferred technical solution of the present invention, in the preparation of the polydimethylsiloxane negative mold, the drying temperature is 50°C - 100°C, preferably 60°C - 80°C.

[0033] In the preferred technical solution of the present invention, in the preparation of the polydimethylsiloxane negative mold, the curing temperature is 80°C - 100°C, preferably 80°C - 90°C.

[0034] In the preferred technical solution of the present invention, the polyvinylpyrrolidone is selected from any one or a combination of PVP K30, PVP K60, and PVP K90.

[0035] In the preferred technical solution of the present invention, in step (2), the concentration of dexmedetomidine hydrochloride is 1-7%, preferably any one of 3%, 5%, and 7%.

[0036] In the preferred technical solution of the present invention, in step (2), the concentration of polyvinylpyrrolidone is 15-20%.

[0037] In the preferred technical solution of the present invention, in step (2), the prepared polyvinylpyrrolidone and dexmedetomidine hydrochloride mixed solution is injected into a polydimethylsiloxane negative mold. After vacuum degassing and drying, the prepared polyvinylpyrrolidone and dexmedetomidine hydrochloride mixed solution is injected into the polydimethylsiloxane negative mold again. After vacuum degassing and drying, it is obtained.

[0038] In the preferred technical solution of the present invention, in step (2), the concentration of dexmedetomidine hydrochloride is 1-2%, preferably any one of 1%, 1.5%, and 2%.

[0039] Another object of the present invention is to provide a method for preparing dexmedetomidine hydrochloride microneedles. The microneedles are made of a drug-loaded needle body layer and a base layer. Among them, the volume ratio of the drug-loaded needle body layer to the base layer is 1:100-200. The drug-loaded needle body layer is prepared from polyvinylpyrrolidone:dexmedetomidine hydrochloride in a mass ratio of 1-15:1. The base layer is prepared by photocrosslinking polyethylene glycol diacrylate. The preparation of the drug-loaded needle body layer includes the following steps. Under stirring (100-200 rpm), dexmedetomidine hydrochloride is added to a polyvinylpyrrolidone solution with a concentration of 10-30% according to the mass ratio of polyvinylpyrrolidone:dexmedetomidine hydrochloride of 1-15:1. The prepared polyvinylpyrrolidone and dexmedetomidine hydrochloride mixed solution is injected into a polydimethylsiloxane negative mold. After vacuum degassing and drying, it is obtained.

[0040] In the preferred technical solution of the present invention, the concentration of polyvinylpyrrolidone is 15-20%.

[0041] In the preferred technical solution of the present invention, the concentration of dexmedetomidine hydrochloride is 1-7%, preferably any one of 3%, 5%, and 7%.

[0042] In the preferred technical solution of the present invention, the concentration of polyvinylpyrrolidone is 15-20%.

[0043] In the preferred technical solution of the present invention, the prepared polyvinylpyrrolidone and dexmedetomidine hydrochloride mixed solution is injected into a polydimethylsiloxane negative mold. After vacuum degassing and drying, the prepared polyvinylpyrrolidone and dexmedetomidine hydrochloride mixed solution is injected into the polydimethylsiloxane negative mold again. After vacuum degassing and drying, it is obtained.

[0044] In the preferred technical solution of the present invention, the concentration of dexmedetomidine hydrochloride is 1-2%, preferably any one of 1%, 1.5%, and 2%.

[0045] In the preferred technical solution of the present invention, the base layer is a square patch.

[0046] In the preferred technical solution of the present invention, the preparation of the base layer includes the following steps: Under stirring (100-200 rpm), mix polyethylene glycol diacrylate (PEGDA400): polyethylene glycol diacrylate (PEGDA600) in a mass ratio of 1:1-5, add 2,4,6-trimethylbenzoyl-diphenylphosphine oxide with a weight percentage concentration of 0.5%, mix for 0.5-1 h, inject the prepared polyethylene glycol diacrylate solution into a polydimethylsiloxane negative mold, and after ultraviolet curing, it is obtained.

[0047] In the preparation of the base layer in the preferred technical solution of the present invention, the mass ratio of polyethylene glycol diacrylate (PEGDA400): polyethylene glycol diacrylate (PEGDA600) is 1:1-2.

[0048] In the preparation of any one of the drug-loading needle body layer and the base layer in the preferred technical solution of the present invention, the vacuum degassing conditions are -0.1 to -0.2 MPa for 2-10 min, preferably -0.1 MPa for 2 min.

[0049] In the preparation of any one of the drug-loading needle body layer and the base layer in the preferred technical solution of the present invention, the ultraviolet curing conditions are λ = 405 nm and the light intensity is 25 mW·cm -2 。

[0050] In the preparation of any one of the drug-loading needle body layer and the base layer in the preferred technical solution of the present invention, the drying temperature is 50°C - 100°C, preferably 60°C - 80°C.

[0051] In the preferred technical solution of the present invention, the preparation of the dexmedetomidine hydrochloride microneedles includes the following steps:

[0052] (1) Immerse the 3D printing master template in a 1-5% polyvinyl alcohol solution for 10 h - 24 h, after drying, fix it, then add defoamed polydimethylsiloxane, cure it, and peel it off to obtain a polydimethylsiloxane negative mold;

[0053] (2) Under the condition of stirring (100 - 200 rpm), in a polyvinylpyrrolidone solution with a concentration of 10 - 30%, dexmedetomidine hydrochloride is added according to the mass ratio of polyvinylpyrrolidone:dexmedetomidine hydrochloride of 1 - 15:1. The prepared mixed solution of polyvinylpyrrolidone and dexmedetomidine hydrochloride is injected into a polydimethylsiloxane female mold. After vacuum degassing, it is dried to obtain the drug-loaded needle layer;

[0054] (3) Under the condition of stirring (100 - 200 rpm), polyethylene glycol diacrylate (PEGDA400):polyethylene glycol diacrylate (PEGDA600) is mixed according to the mass ratio of 1:1 - 5, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide with a weight percentage concentration of 0.5% is added. After mixing for 0.5 - 1 h, the prepared polyethylene glycol diacrylate solution is injected into a polydimethylsiloxane female mold. After ultraviolet curing, the base layer is obtained;

[0055] (4) Demold to obtain the product.

[0056] In the preferred technical solution of the present invention, the microneedles are prepared by a method combining 3D printing and polydimethylsiloxane female mold replication.

[0057] In the preferred technical solution of the present invention, the preparation of the polydimethylsiloxane female mold includes the following steps: The 3D printing master template is immersed in a 1 - 5% polyvinyl alcohol solution for 10 h - 24 h. After drying, it is fixed, and then defoamed polydimethylsiloxane is added. After curing, it is peeled off to obtain the product.

[0058] In the preferred technical solution of the present invention, in the preparation of the polydimethylsiloxane female mold, the concentration of the polyvinyl alcohol solution is 1 - 2%.

[0059] In the preferred technical solution of the present invention, in the preparation of the polydimethylsiloxane female mold, the drying temperature is 50°C - 100°C, preferably 60°C - 80°C.

[0060] In the preferred technical solution of the present invention, in the preparation of the polydimethylsiloxane female mold, the curing temperature is 80°C - 100°C, preferably 80°C - 90°C.

[0061] In the preferred technical solution of the present invention, the polyvinylpyrrolidone is selected from any one or a combination of PVP K30, PVP K60, and PVP K90.

[0062] In the preferred technical solution of the present invention, in step (2), the concentration of dexmedetomidine hydrochloride is 1 - 7%, preferably any one of 3%, 5%, and 7%.

[0063] In the preferred technical solution of the present invention, in step (2), the concentration of the polyvinylpyrrolidone is 15 - 20%.

[0064] In the preferred technical solution of the present invention, in step (2), the prepared polyvinylpyrrolidone and dexmedetomidine hydrochloride mixed solution is injected into a polydimethylsiloxane female mold. After vacuum degassing and drying, the prepared polyvinylpyrrolidone and dexmedetomidine hydrochloride mixed solution is injected into the polydimethylsiloxane female mold again. After vacuum degassing and drying, it is obtained.

[0065] In the preferred technical solution of the present invention, in step (2), the concentration of dexmedetomidine hydrochloride is 1-2%, preferably any one of 1%, 1.5%, and 2%.

[0066] Another object of the present invention is to provide the application of dexmedetomidine hydrochloride microneedles in the preparation of drugs for sedation, analgesia, and anti-anxiety.

[0067] Unless otherwise specified, the present invention uses a handheld electron microscope (AM7915MZTL, Wuxi Diwei Optics Co., Ltd.), a scanning electron microscope (Hitachi SU8010, Hitachi, Ltd.), and optical coherence tomography (Tomographic, Hangzhou Jienuofei Biotechnology Co., Ltd.) to observe the morphology of dexmedetomidine hydrochloride microneedles.

[0068] The present invention uses an MTS C42.502y texture analyzer (MTS Systems, USA) to detect the mechanical properties of dexmedetomidine hydrochloride microneedles. The dexmedetomidine hydrochloride microneedle sample to be tested is fixed on a metal stage, and the tip is vertically aligned with a Φ13.3 mm cylindrical probe. A vertical pressure is applied at a rate of 0.05 mm·min-1, with an initial distance of 0.5 cm, a trigger force of 0.05 N, and a termination force of 70 N. The fracture force is calculated through the force-displacement curve: the maximum load when the microneedle undergoes structural damage (target value ≥ 0.030 N / needle).

[0069] Unless otherwise specified, the present invention uses high performance liquid chromatography to detect the content of dexmedetomidine hydrochloride in the microneedles: The microneedles to be tested are placed in a 100 mL volumetric flask, dissolved at 37 °C and 100 r / min, filtered through a 0.22 μm microporous filter membrane, and the subsequent filtrate is taken as the sample solution for injection and detection. Inertsil ODS-3, C18 chromatographic column (U300, Thermo Fisher Scientific, USA, 4.6 mm × 150 mm, 5 μm), mobile phase: 0.71 g / L disodium hydrogen phosphate (adjusted to pH 7.0 with 16 g / L sodium dihydrogen phosphate dihydrate solution)-methanol (40:60), flow rate: 1.0 mL / min, injection volume: 20 μL, column temperature: 30 °C, detection wavelength: 220 nm.

[0070] Unless otherwise specified, when the present invention relates to the percentage between liquids, the percentage is volume / volume percentage; when the present invention relates to the percentage between a liquid and a solid, the percentage is volume / weight percentage; when the present invention relates to the percentage between a solid and a liquid, the percentage is weight / volume percentage; and the rest is weight / weight percentage.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] 1. The present invention innovatively combines the surface projection 3D printing technology and the PDMS mold casting technology to prepare dexmedetomidine hydrochloride microneedles. Polyvinylpyrrolidone is scientifically selected as the material for the needle body layer, and polyethylene glycol diacrylate with rapid curing is selected as the material for the base layer. After curing, the back lining layer is hard and flat, and can be uniformly stressed. The components and ratios of polyethylene glycol diacrylate are scientifically selected, and the morphology, geometric shape, mechanical properties, mechanical strength, contact angle, aspect ratio of the needle body, needle body structure, needle body model, array arrangement, dissolution rate, content, drug release, onset time and other parameters of the microneedles are also scientifically optimized. The prepared dexmedetomidine hydrochloride microneedles have a neatly arranged needle tip structure, and the mechanical strength is easy to penetrate the skin cutin layer. Moreover, dexmedetomidine hydrochloride is concentrated at the needle tip part and does not diffuse to the base layer, providing technical guarantee for the accuracy of the dosage, medication economy and avoiding drug waste. And the base layer is easier to remove and effectively overcomes the uncomfortable adhesion and medication discomfort on the skin, reasonably balancing the mechanical properties and precise release of the soluble microneedles, ensuring that the needle body can effectively penetrate and stably release the drug. A dexmedetomidine hydrochloride microneedle with gradient doses (such as 200 μg / patch, 400 μg / patch, 600 μg / patch) and precise regulation is successfully constructed, with both high-precision structure and excellent mechanical strength. After being inserted into the skin, it can quickly dissolve and release the drug and reach the target dose, and then realize the diffusion and delivery of the drug through the epidermal-dermal concentration gradient, achieving painless / mild pain penetration of the cutin layer, rapid onset, long drug effect maintenance time (≥6h). Combining the characteristics of rapid skin healing and excellent biocompatibility, it realizes the transdermal precise administration of dexmedetomidine hydrochloride, significantly shortens the preparation time of the microneedles, has no irritation to the skin and avoids the infection risk, significantly improves its bioavailability and the safety and effectiveness of medication, significantly reduces the dose-related side effects, provides a new choice for patients' autonomous and convenient medication, and significantly improves the medication compliance of patients.

[0073] 2. The present invention uses 3D printing technology combined with PDMS mold replication method to prepare dexmedetomidine hydrochloride microneedles. Firstly, it significantly improves the accuracy, durability and mechanical strength of the PDMS negative mold (the tip fracture rate < 10%), effectively solving the problems of large demolding stress and high tip residue rate existing in the PDMS replication method. Secondly, the base layer is rapidly cured by ultraviolet light irradiation, significantly shortening the preparation time of the microneedles and improving the production efficiency. Thirdly, an innovative low-concentration secondary concentration process is adopted, significantly increasing the drug loading amount of the needle body layer and significantly reducing the generation of bubbles and dosage errors. The preparation method of the present invention has the advantages of simple operation, high yield, better cost, wide applicability to the population and suitability for industrial production, etc. Description of the Drawings

[0074] Figure 1 Morphology observation of the dexmedetomidine hydrochloride microneedles of the present invention;

[0075] Figure 2 Investigation on the mechanical properties of the dexmedetomidine hydrochloride microneedles of the present invention;

[0076] Figure 3 Research on the puncture and healing conditions of the dexmedetomidine hydrochloride microneedles of the present invention;

[0077] Figure 4 Investigation on the in vitro drug release of the dexmedetomidine hydrochloride microneedles of the present invention;

[0078] Figure 5 Investigation on the analgesic effect of the dexmedetomidine hydrochloride microneedles of the present invention. Detailed Embodiments

[0079] The following will specifically illustrate the present invention in combination with embodiments. The embodiments of the present invention are only used to illustrate the technical solutions of the present invention and do not limit the essence of the present invention.

[0080] The preparation of the polydimethylsiloxane negative mold in the detailed embodiments includes the following steps:

[0081] 1) Preparation of the 3D printed microneedle master template

[0082] Install the slicing software BMF 3D slicer V1.6.4 on the industrial control computer of the printer, import the.STL file of the microneedle three-dimensional model, slice the three-dimensional model, set the slice layer thickness to 10 μm, and the XY plane accuracy to 10 μm to obtain.png format pictures. The program will automatically name the sliced two-dimensional pictures in sequence. In the 3D Printing System S-140S1.0.1 software of the printer, select the stitching printing mode, import the.png format pictures, set the printing parameters: exposure time (Exposure time, Exp-t), exposure intensity (Intensity Intst), number of scraper movements (Scra), etc. After saving the printing parameters, select high-temperature resistant resin (HLT, Shenzhen Magic Square Precision) to prepare the 3D printing master template.

[0083] After soaking the prepared 3D printing master template in ethanol for 1 h, perform ultraviolet secondary curing for 2 - 5 min, and then soak it in ethanol for 24 h to obtain the 3D printing microneedle master template:

[0084] Drug-loaded needle body layer: quadrangular pyramid, upper side length 10 μm, lower side length 300 μm, height 900 μm;

[0085] Base layer: cube, length 1.23 cm, width 1.23 cm, height 2 mm.

[0086] 2) Preparation of the polydimethylsiloxane negative mold: Immerse the 3D printing master template in a 1% polyvinyl alcohol solution for 12 h, dry it at 60 °C, then fix it with the tip upward in a 35 mm culture dish. After defoaming the polydimethylsiloxane, add it to the culture dish and cure it at 80 °C for 3 h, then peel it off to obtain it.

[0087] Preparation of the polyethylene glycol diacrylate (PEGDA) solution in the specific implementation manner: Under stirring (180 rpm), uniformly mix 5 g of polyethylene glycol diacrylate (PEGDA400) and 5 g of polyethylene glycol diacrylate (PEGDA600), and then add 0.05 g of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TMO), and react for 30 min to obtain it.

[0088] Preparation of dexmedetomidine hydrochloride cream in the specific implementation manner: Place 10 mg of dexmedetomidine hydrochloride (Sichuan Ren'an Pharmaceutical), 2 g of polyvinylpyrrolidone K90, and 0.6 g of sodium carboxymethyl starch in 10 mL of water and mix evenly to obtain it.

[0089] Preparation of dexmedetomidine hydrochloride injection in the specific implementation manner: Dissolve 0.005 g of dexmedetomidine hydrochloride (Sichuan Ren'an Pharmaceutical) in 5 mL of physiological saline to obtain a 1 mg / mL injection.

[0090] Example 1 Preparation of Dexmedetomidine Hydrochloride Microneedles of the Invention

[0091] The preparation of dexmedetomidine hydrochloride microneedles includes the following steps:

[0092] (1) After stirring (200 rpm * 10 min), 0.15 g of polyvinylpyrrolidone K90 is dissolved in 0.84 g of water, and then 0.01 g of dexmedetomidine hydrochloride is added. After shaking for 5 h, a 1 mL mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride is prepared;

[0093] (2) Inject 150 μL of the mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride into the polydimethylsiloxane female mold. After vacuum degassing treatment (-0.1 MPa, 2 min), the excess solution is scraped off and dried for 2 h. Then, inject 150 μL of the mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride into the polydimethylsiloxane female mold again. After vacuum degassing treatment (-0.1 MPa, 2 min), the excess solution is scraped off and dried for 2 h to prepare a drug-loaded needle body layer with a volume of 3 μL;

[0094] (3) Inject the polyethylene glycol diacrylate solution into the polydimethylsiloxane female mold. After vacuum degassing treatment (-0.1 MPa, 2 min), it is cured by ultraviolet light (λ: 405 nm, d = 5 cm, output power: 25 mW·cm -2 ) for 1 min to prepare a base layer with a volume of 300 μL;

[0095] (4) After standing for 1 - 2 h, demold.

[0096] Upon detection, the content of dexmedetomidine hydrochloride in the microneedles is 209.99 ± 27.56 μg / patch.

[0097] The morphology of dexmedetomidine hydrochloride microneedles was observed using a hand-held microscope and a scanning electron microscope, and the results are shown in Figure 1 A and Figure 1 B. The needle body has good formability, the array is arranged neatly, complete without missing, and has a quadrangular pyramid structure. The microneedles were scanned using micro-computed tomography (Micro computed tomography, micro-CT), and the results showed that the drug-loading amount of the needle body layer of the microneedles is high and there are no obvious air bubbles generated with the base layer.

[0098] According to the method of the invention, the breaking force of dexmedetomidine hydrochloride microneedles is higher than 0.4 N / needle, and the results are shown in Figure 2 .

[0099] Example 2 Preparation of Dexmedetomidine Hydrochloride Microneedles of the Invention

[0100] The preparation of dexmedetomidine hydrochloride microneedles comprises the following steps:

[0101] (1) After stirring (200 rpm * 10 min), 0.15 g of polyvinylpyrrolidone K90 was dissolved in 0.835 g of water, and then 0.015 g of dexmedetomidine hydrochloride was added. After shaking for 5 h, a 1 mL mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride was prepared;

[0102] (2) 150 μL of the mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride was injected into the polydimethylsiloxane female mold. After vacuum degassing treatment (-0.1 MPa, 2 min), the excess solution was scraped off and dried for 2 h. Then, 150 μL of the mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride was injected into the polydimethylsiloxane female mold again. After vacuum degassing treatment (-0.1 MPa, 2 min), the excess solution was scraped off and dried for 2 h to obtain a drug-loaded needle body layer with a volume of 3 μL;

[0103] (3) The polyethylene glycol diacrylate solution was injected into the polydimethylsiloxane female mold. After vacuum degassing treatment (-0.1 MPa, 2 min), it was cured by ultraviolet light (λ: 405 nm, d = 5 cm, output power: 25 mW·cm -2 ) After 1 min, a base layer with a volume of 300 μL was obtained;

[0104] (4) After standing for 1 - 2 h, demolding was carried out to obtain the product.

[0105] After detection, the content of dexmedetomidine hydrochloride in the microneedles was 405.31 ± 30.31 μg / patch.

[0106] The morphology of dexmedetomidine hydrochloride microneedles was observed by using a hand-held microscope and a scanning electron microscope, and the results are shown in Figure 1 A and Figure 1 B. The needle body has good formability, the array is arranged neatly, complete without missing, and presents a quadrangular pyramid structure. The microneedles were scanned by micro-computed tomography technology, and the results showed that the drug loading amount of the needle body layer of the microneedles was high and there were no obvious air bubbles generated with the base layer.

[0107] According to the method of the present invention, the breaking force of dexmedetomidine hydrochloride microneedles was detected to be higher than 0.4 N / needle, and the results are shown in Figure 2 .

[0108] Example 3 The preparation of dexmedetomidine hydrochloride microneedles of the present invention

[0109] The preparation of dexmedetomidine hydrochloride microneedles comprises the following steps:

[0110] (1) After stirring (200 rpm * 10 min), dissolve 0.15 g of polyvinylpyrrolidone K90 in 0.83 g of water, then add 0.02 g of dexmedetomidine hydrochloride, and place it in a shaker at 25 °C * 100 rpm for 5 h to obtain 1 mL of a mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride;

[0111] (2) Inject 150 μL of the mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride into the polydimethylsiloxane female mold. After vacuum degassing treatment (-0.1 MPa, 2 min), scrape off the excess solution and dry for 2 h. Then, inject 150 μL of the mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride into the polydimethylsiloxane female mold again. After vacuum degassing treatment (-0.1 MPa, 2 min), scrape off the excess solution and dry for 2 h to obtain a drug-loaded needle body layer with a volume of 3 μL;

[0112] (3) Inject the polyethylene glycol diacrylate solution into the polydimethylsiloxane female mold. After vacuum degassing treatment (-0.1 MPa, 2 min), perform ultraviolet curing (λ: 405 nm, d = 5 cm, output power: 25 mW·cm -2 ) for 1 min to obtain a base layer with a volume of 300 μL;

[0113] (4) After standing for 1 - 2 h, demold to obtain the product.

[0114] After testing, the content of dexmedetomidine hydrochloride in the microneedles is 621.61 ± 34.43 μg / patch.

[0115] The morphology of the dexmedetomidine hydrochloride microneedles was observed using a handheld microscope and a scanning electron microscope. The results are shown in Figure 1 A and Figure 1 B. The needle body has good formability, the array is arranged neatly, complete without missing parts, and has a quadrangular pyramid structure. The microneedles were scanned using micro-computed tomography technology, and the results showed that the drug-loading amount of the needle body layer of the microneedles is high and there are no obvious air bubbles in the base layer.

[0116] According to the method of the present invention, the breaking force of the dexmedetomidine hydrochloride microneedles was detected to be higher than 0.4 N / needle. The results are shown in Figure 2 .

[0117] Example 4 Preparation of the dexmedetomidine hydrochloride microneedles of the present invention

[0118] The preparation of the dexmedetomidine hydrochloride microneedles includes the following steps:

[0119] (1) After stirring (200 rpm * 10 min), 0.15 g of polyvinylpyrrolidone K90 was dissolved in 0.82 g of water, and then 0.03 g of dexmedetomidine hydrochloride was added. After shaking for 5 h, a 1 mL mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride was prepared.

[0120] (2) 150 μL of the mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride was injected into a polydimethylsiloxane female mold. After vacuum degassing treatment (-0.1 MPa, 2 min), the excess solution was scraped off and dried for 2 h to obtain a drug-loaded needle body layer with a volume of 2 μL.

[0121] (3) A polyethylene glycol diacrylate solution was injected into the polydimethylsiloxane female mold. After vacuum degassing treatment (-0.1 MPa, 2 min), it was ultraviolet cured (λ: 405 nm, d = 5 cm, output power: 25 mW·cm -2 ) After 1 min, a base layer with a volume of 300 μL was obtained.

[0122] (4) After standing for 1 - 2 h, demolding was carried out. After detection, the content of dexmedetomidine in the dexmedetomidine hydrochloride microneedles was 223.14 + 31.79 μg / patch.

[0123] Example 5 Preparation of dexmedetomidine hydrochloride microneedles of the present invention

[0124] The preparation of dexmedetomidine hydrochloride microneedles includes the following steps:

[0125] (1) After stirring (200 rpm * 10 min), 0.15 g of polyvinylpyrrolidone K90 was dissolved in 0.8 g of water, and then 0.05 g of dexmedetomidine hydrochloride was added. After shaking for 5 h, a 1 mL mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride was prepared.

[0126] (2) 150 μL of the mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride was injected into a polydimethylsiloxane female mold. After vacuum degassing treatment (-0.1 MPa, 2 min), the excess solution was scraped off and dried for 2 h to obtain a drug-loaded needle body layer with a volume of 2 μL.

[0127] (3) A polyethylene glycol diacrylate solution was injected into the polydimethylsiloxane female mold. After vacuum degassing treatment (-0.1 MPa, 2 min), it was ultraviolet cured (λ: 405 nm, d = 5 cm, output power: 25 mW·cm -2 ) After 1 min, a base layer with a volume of 300 μL was obtained.

[0128] After standing for 1 - 2 h, demoulding, and through detection, the content of dexmedetomidine hydrochloride in the dexmedetomidine hydrochloride microneedles is 418.47 + 36.61 μg / patch.

[0129] Example 6 Preparation of the dexmedetomidine hydrochloride microneedles of the present invention

[0130] The preparation of the dexmedetomidine hydrochloride microneedles includes the following steps:

[0131] (1) After stirring (200 rpm * 10 min), dissolve 0.15 g of polyvinylpyrrolidone K90 in 0.78 g of water, then add 0.07 g of dexmedetomidine hydrochloride, place it in a shaker at 25 °C * 100 rpm for 5 h, and prepare 1 mL of a mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride;

[0132] (2) Inject 150 μL of the mixed solution of polyvinylpyrrolidone K90 and dexmedetomidine hydrochloride into a polydimethylsiloxane female mold. After vacuum degassing treatment (-0.1 MPa, 2 min), scrape off the excess solution and dry for 2 h to prepare a drug - loaded needle body layer with a volume of 2 μL;

[0133] (3) Inject a polyethylene glycol diacrylate solution into the polydimethylsiloxane female mold. After vacuum degassing treatment (-0.1 MPa, 2 min), perform ultraviolet curing (λ: 405 nm, d = 5 cm, output power: 25 mW·cm -2 ) for 1 min to prepare a base layer with a volume of 300 μL;

[0134] (4) After standing for 1 - 2 h, demoulding, and that's it. Through detection, the content of dexmedetomidine hydrochloride in the dexmedetomidine hydrochloride microneedles is 625.75 + 46.26 μg / patch.

[0135] Test Example 1 Investigation on the puncture situation of the dexmedetomidine hydrochloride microneedles of the present invention

[0136] Taking the dexmedetomidine hydrochloride microneedles of Example 2 as an example, using 4% agarose gel to simulate the skin for a puncture experiment, after pressing, observe with a handheld electron microscope, and the microneedle puncture rate is 100%.

[0137]

[0138] Taking the dexmedetomidine hydrochloride microneedles of Example 2 as an example, after pressing the skin of hair - removed mice for 3 min, remove the microneedle array from the skin surface. At 0 min, 30 min, and 60 min after removing the microneedles, scan the skin using Tomographic Optical Coherence Tomography (OCT). The results are shown in Figure 3。

[0139] The microneedle puncture of dexmedetomidine hydrochloride of the present invention causes very little trauma to the skin, does not cause persistent tissue damage, and is non-irritating to the skin, minimizing the risk of infection.

[0140] Test Example 2 Investigation on drug release of dexmedetomidine hydrochloride microneedles of the present invention

[0141] In the preparation of dexmedetomidine hydrochloride microneedles in Example 2, rhodamine b was added as a fluorescent marker. The microneedles were inserted into 4% agarose gel, and the microneedles were removed at (0 s, 30 s, 1 min, 3 min, 10 min). The dissolution of the microneedles was observed under a CKX53 fluorescence microscope under DIC light source and BP475 light source. The results are shown in Figure 4 。

[0142] Test Example 3 Investigation on analgesic effect of dexmedetomidine hydrochloride microneedles of the present invention

[0143] Forty-eight 6- to 8-week-old, SPF-grade female BALB / c mice were divided into 6 groups of 8 mice each.

[0144] The experimental mice were adaptively fed for 2 weeks. One day before modeling, the mice were anesthetized with isoflurane, the hair on the back of the mice was shaved with a clipper, the skin on the back of the mice was moistened with water, a thin layer of depilatory cream was applied and then wiped off with clean water. The grouping treatments were as follows:

[0145] Blank group: No treatment was performed;

[0146] Control group 1: 20 μL of dexmedetomidine hydrochloride cream with a concentration of 1 mg / mL was applied to the back skin of the mice;

[0147] Control group 2: 20 μL of dexmedetomidine hydrochloride injection with a concentration of 1 mg / mL was intramuscularly injected;

[0148] Experimental group 1: The microneedles of Example 1 (20 μg) were applied to the back skin of the mice;

[0149] Experimental group 2: The microneedles of Example 2 (40 μg) were applied to the back skin of the mice;

[0150] Experimental group 3: The microneedles of Example 3 (60 μg) were applied to the back skin of the mice.

[0151] 1. Observe the central response of the animals to thermal stimulation (such as licking the hind paws, jumping) to evaluate the central analgesic effect of the drug.

[0152] After weighing the mice, allow them to acclimatize to the environment for 15 - 30 min. Heat the hot plate to 55 °C, then place the mice on the hot plate and start timing. After drug treatment (15 min, 30 min, 60 min, 90 min, 120 min, 6 h), and take the average value of the test results with a 15 - min interval between two detections as the pain threshold. The results are shown in Figure 5 A. The central analgesic effect of the experimental group took effect rapidly, and the analgesic effect lasted for 6 h. At 60 min, the pain threshold of the microneedle group was 3.07 times that of the cream group.

[0153] 2. Observe the spinal reflex of animals to heat stimulation (such as tail flick) to evaluate the peripheral analgesic effect of the drug.

[0154] After weighing the mice, allow them to acclimatize in the test room for 15 - 30 min. First, fix the mice in a fixator, heat the constant temperature water bath to 52 °C, and immerse 3 cm of the mouse's tail in hot water. The mouse shows a tail flick phenomenon due to heat stimulation.

[0155] After drug treatment (15 min, 30 min, 60 min, 90 min, 120 min, 6 h), and take the average value of the test results with a 15 - min interval between two detections as the pain threshold. The results are shown in Figure 5 B. The pain threshold of the experimental group was 3.56 times that of the cream group.

[0156] The above description of the specific embodiments of the present invention does not limit the present invention. Those skilled in the art can make various changes or deformations according to the present invention. As long as they do not depart from the spirit of the present invention, they should all fall within the scope of the present invention.

Claims

1. A dexmedetomidine hydrochloride microneedle, which is made of a drug-loaded needle body layer and a base layer, wherein, Drug-loaded needle body layer: The volume ratio of the base layer is 1:100 - 200. The drug-loaded needle body layer is prepared from polyvinylpyrrolidone and dexmedetomidine hydrochloride in a mass ratio of 1 - 15:1, and the base layer is prepared by photocrosslinking of polyethylene glycol diacrylate.

2. The microneedle according to claim 1, wherein the drug-loaded needle body layer is a quadrangular pyramid patch.

3. The microneedle according to any one of claims 1 - 2, the preparation of the drug-loaded needle body layer comprises the following steps: Under the condition of stirring (100 - 200 rpm), in a polyvinylpyrrolidone solution with a concentration of 10 - 30%, add dexmedetomidine hydrochloride according to the mass ratio of polyvinylpyrrolidone:dexmedetomidine hydrochloride of 1 - 15:

1. Inject the prepared mixed solution of polyvinylpyrrolidone and dexmedetomidine hydrochloride into a polydimethylsiloxane negative mold, after vacuum degassing, dry it to obtain.

4. The microneedle according to any one of claims 1 - 3, wherein the base layer is a square patch.

5. The microneedle according to any one of claims 1 - 4, the preparation of the base layer comprises the following steps: Under the condition of stirring (100 - 200 rpm), mix polyethylene glycol diacrylate (PEGDA400) and polyethylene glycol diacrylate (PEGDA600) in a mass ratio of 1:1 - 5, add 2,4,6-trimethylbenzoyl-diphenylphosphine oxide with a weight percentage concentration of 0.5%, mix for 0.5 - 1 h, inject the prepared polyethylene glycol diacrylate solution into a polydimethylsiloxane negative mold, after ultraviolet curing, obtain.

6. The preparation method of the dexmedetomidine hydrochloride microneedles according to any one of claims 1-5, wherein the microneedles are made of a drug-loaded needle body layer and a base layer, and among them, Drug-loaded needle body layer: The volume ratio of the base layer is 1:100 - 200. The drug-loaded needle body layer is prepared from polyvinylpyrrolidone and dexmedetomidine hydrochloride in a mass ratio of 1 - 15:1, and the base layer is prepared by photocrosslinking of polyethylene glycol diacrylate. The preparation of the drug-loaded needle body layer comprises the following steps: Under the condition of stirring (100 - 200 rpm), in a polyvinylpyrrolidone solution with a concentration of 10 - 30%, add dexmedetomidine hydrochloride according to the mass ratio of polyvinylpyrrolidone:dexmedetomidine hydrochloride of 1 - 15:

1. Inject the prepared mixed solution of polyvinylpyrrolidone and dexmedetomidine hydrochloride into a polydimethylsiloxane negative mold, after vacuum degassing, dry it to obtain.

7. The preparation method according to claim 6, the preparation of the dexmedetomidine hydrochloride microneedle comprises the following steps: (1) Immerse the 3D printing master template in a 1 - 5% polyvinyl alcohol solution for 10 h - 24 h, after drying, fix it, then add defoamed polydimethylsiloxane, after curing, peel it off to obtain a polydimethylsiloxane negative mold; (2) Under the condition of stirring (100 - 200 rpm), in a polyvinylpyrrolidone solution with a concentration of 10 - 30%, add dexmedetomidine hydrochloride according to the mass ratio of polyvinylpyrrolidone:dexmedetomidine hydrochloride of 1 - 15:

1. Inject the prepared mixed solution of polyvinylpyrrolidone and dexmedetomidine hydrochloride into a polydimethylsiloxane negative mold, after vacuum degassing, dry it to obtain the drug-loaded needle body layer; (3) Under the condition of stirring (100 - 200 rpm), mix polyethylene glycol diacrylate (PEGDA400): polyethylene glycol diacrylate (PEGDA600) in a mass ratio of 1:1 - 5, add 2,4,6-trimethylbenzoyl-diphenylphosphine oxide with a weight percentage concentration of 0.5%, mix for 0.5 - 1 h, inject the prepared polyethylene glycol diacrylate solution into the polydimethylsiloxane negative film, and after ultraviolet curing, obtain the base layer; (4) Demold to obtain the product.

8. The preparation method according to any one of claims 6 - 7, wherein the microneedles are prepared by 3D printing combined with the method of replicating a polydimethylsiloxane negative mold.

9. The preparation method according to any one of claims 6 - 8, wherein the preparation of the polydimethylsiloxane negative mold comprises the following steps: Immerse the 3D printed master template in a 1 - 5% polyvinyl alcohol solution for 10 h - 24 h, after drying, fix it, then add polydimethylsiloxane after defoaming treatment, cure it, and peel it off to obtain the product.

10. The application of the dexmedetomidine hydrochloride microneedles according to any one of claims 1 - 5 in the preparation of drugs for sedation, analgesia, and anti - anxiety.

Images