Rasagiline pamoate long-acting sustained-release microsphere and preparation method thereof

Abstract

The invention relates to the technical field of pharmaceutical preparations, and particularly discloses rasagiline pamoate long-acting sustained-release microspheres and a preparation method thereof, the long-acting sustained-release microspheres comprise rasagiline pamoate and a polylactic acid polymer, and the long-acting sustained-release microspheres have a good sustained-release effect. The preparation method comprises the following steps: firstly, preparing rasagiline into pamoate so as to reduce the solubility of rasagiline; in the preparation process of the long-acting sustained-release microspheres, the drug release rate is regulated and controlled by adjusting the proportion of the low-molecular-weight polylactic acid, the sudden drug release phenomenon is reduced by reducing the curing temperature, and the preparation process is suitable for industrial large-scale production. The finally obtained long-acting sustained-release microsphere composition can be used for preparing a medicine for treating Parkinson's disease.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical formulation technology, specifically relating to a long-acting sustained-release microsphere of rasagiline dihydroxynaphthyl acid and its preparation method. Background Technology

[0002] Parkinson's disease (PD) is a common chronic neurodegenerative disease affecting middle-aged and elderly people. It is mainly caused by the progressive death of dopaminergic neurons in the substantia nigra of the brain, leading to insufficient levels of the neurotransmitter dopamine, which in turn causes motor and non-motor symptoms. With the aging of the world's population, the incidence of Parkinson's disease is increasing year by year, seriously affecting the quality of life of patients and placing a great burden on patients' families and society.

[0003] Rasagiline is a monoamine oxidase type B (MAO-B) inhibitor. It increases brain dopamine levels by selectively inhibiting the activity of MAO-B enzymes, reducing dopamine breakdown. The molecular formula of rasagiline is C2. 12 H 13 N, chemically named (R)-N-(2-propynyl)-2,3-dihydroinden-1-amine, has the following chemical structural formula: .

[0004] Rasagiline, jointly developed and manufactured by Lundbeck of Denmark and Teva of Israel, was approved by the FDA in 2006. Its mesylate form (rasagiline mesylate) has become the commonly used drug form in clinical practice due to its physicochemical properties being more suitable for clinical needs. Currently, rasagiline is mainly available in oral tablet form, requiring daily administration. However, Parkinson's disease patients often experience swallowing difficulties, leading to poor medication adherence, which in turn causes fluctuations in blood drug concentrations, resulting in the "on / off" phenomenon and related complications, causing significant inconvenience to both patients and caregivers. Therefore, there is a clinical need for a long-acting, sustained-release formulation of rasagiline.

[0005] In their paper "Controlled release of rasagiline mesylate promotes neuroprotection in a rotenone-induced advanced model of Parkinson's disease. International Journal of Pharmaceutics, 2012, 438(1-2)", Marcos Fernández et al. proposed using lactide-glycolic acid copolymer 5050 as a sustained-release material and prepared PLGA microspheres loaded with rasagiline mesylate using both single emulsion (O / W) and double emulsion (W / O / W) solvent evaporation methods. The microspheres prepared in this study have significant shortcomings: firstly, their drug loading and encapsulation efficiency are relatively low, which requires a larger volume of drug to be injected to achieve the same therapeutic dose, significantly reducing patient acceptance; secondly, the drug release period of the microspheres is short, lasting only two weeks, failing to achieve the ideal long-acting release effect, and exhibiting a prominent burst release problem: the drug release reaches 10%-25% within one hour of administration, potentially affecting drug safety and efficacy stability.

[0006] Patent CN107049985A discloses a long-acting rasagiline formulation that achieves delayed drug release by combining two types of microspheres with specific average particle sizes (0.5-5 μm and 20-150 μm, respectively), while significantly reducing fluctuations in plasma rasagiline concentration. However, production requires the separate preparation and mixing of the two particle size ranges of microspheres, increasing process complexity and cost. Furthermore, the preparation of the 0.5-5 μm microspheres relies on ultrasonic homogenization or high-pressure injection at 1000-1500 bar, placing high demands on equipment and operating conditions. In terms of in vivo distribution, as a passively targeted formulation, the distribution of its microparticles after intramuscular injection is dominated by particle size. Microparticles smaller than 7 μm are easily taken up by hepatic and splenic macrophages, making it difficult to reach target tissues and reducing therapeutic efficacy. Conventional polymer microspheres are designed to avoid macrophage phagocytosis to ensure targeting and efficacy, further highlighting the limitations of this patent in particle size design.

[0007] Korean patent KR20210014289A discloses a method for preparing rasagiline microspheres using polylactic acid (PLA) via an O / W emulsion solvent evaporation process, achieving a release cycle of up to four weeks. However, its theoretical drug loading capacity is only 8%, while the actual drug loading capacity is only 3.5-5.0%, resulting in a low encapsulation efficiency of only 43.75%-62.5%.

[0008] Patent CN112190553A discloses a method for preparing rasagiline mesylate microspheres using a double emulsion solvent evaporation method. By adding an appropriate amount of tannic acid as a release regulator to the internal aqueous phase, the burst release phenomenon of the drug-loaded microspheres is reduced, improving the stability of the primary emulsion system. Experimental results show that the drug loading of the prepared rasagiline mesylate microspheres is 5.2%-7.5%, the encapsulation efficiency is 82.20%-92.36%, and its accelerated release in vitro lasts for five days. Although this double emulsion method has advantages over the single emulsion method in scenarios such as encapsulating water-soluble drugs, the double emulsion method is cumbersome, has a longer production cycle, and is more difficult to maintain stability during scale-up production, easily leading to problems such as large batch-to-batch variations and unstable quality.

[0009] Patents CN116211840A and CN118680910A both disclose an injectable in-situ gel implant of rasagiline and its salts. The former uses PLGA / PLA as the carrier material, while the latter uses soybean lecithin / dioleoyl glycerol as the carrier. Both of these in-situ gel formulations can achieve slow drug release, with release cycles of up to 30 days and 7 days, respectively, demonstrating potential for long-acting drug delivery. However, they have the following technical drawbacks: First, the long-term stability of the multi-component homogeneous solution is poor, requiring separation and storage using special kits such as dual-chamber syringes, and temporary mixing before use, increasing operational complexity and storage costs. Second, this formulation contains organic solvents such as N-methylpyrrolidone and dimethyl sulfoxide, posing a biocompatibility risk and potentially causing local or systemic irritation and allergic reactions, thus limiting its clinical applicability.

[0010] Therefore, there is a need for rasagiline microspheres with high drug loading capacity, long-lasting sustained release, and simple preparation process. Summary of the Invention

[0011] This invention aims to overcome the shortcomings of the prior art by providing a long-acting sustained-release microsphere of rasagiline dihydroxynaphthyl acid and its preparation method. The long-acting sustained-release microsphere comprises rasagiline dihydroxynaphthyl acid and polylactic acid polymers, exhibiting excellent sustained-release effects, providing a continuous and stable drug release with high drug loading, low burst release, and high encapsulation efficiency. The preparation method first involves converting rasagiline into a dihydroxynaphthyl acid salt to reduce its solubility. During the preparation of the long-acting sustained-release microspheres, the drug release rate is controlled by adjusting the proportion of low molecular weight polylactic acid, and burst release is reduced by lowering the curing temperature. This preparation process is simple and suitable for industrial-scale production. The resulting long-acting sustained-release microsphere composition can be used to prepare drugs for treating Parkinson's disease, thus providing more reliable technical support for the treatment of Parkinson's patients with rasagiline.

[0012] A long-acting sustained-release microsphere containing rasagiline dihydroxynaphthyl acid and polylactic acid polymers, wherein rasagiline dihydroxynaphthyl acid accounts for 10%-40% of the total weight of the microspheres and polylactic acid polymers account for 60%-90% of the total weight of the microspheres.

[0013] The microspheres described above use rasagiline dihydroxynaphthyl acid as the main active ingredient of the drug, wherein rasagiline dihydroxynaphthyl acid has the following structural formula: The preparation method of the above-mentioned rasagiline dihydroxynaphthyl acid is as follows: Rasagilan mesylate and disodium dihydroxynaphthyl acid monohydrate were dissolved separately in distilled water and stirred at room temperature. The disodium dihydroxynaphthyl acid monohydrate solution was then slowly added to the rasagilan mesylate solution and reacted for 0.5-2 hours, resulting in precipitation. After filtration, the precipitate was vacuum dried at 40°C for 46-48 hours to obtain rasagilan dihydroxynaphthyl acid.

[0014] The molar ratio of rasagiline mesylate to disodium dihydroxynaphthyl acid monohydrate is 2:1-1.1, with the optimal ratio being 2:1. The solid-liquid ratio of rasagiline mesylate to distilled water in the optimal rasagiline mesylate solution is 6.07 g:60 mL. Furthermore, the solid-liquid ratio of disodium dihydroxynaphthyl acid monohydrate to distilled water in the optimal disodium dihydroxynaphthyl acid monohydrate solution is 4.91 g:60 mL.

[0015] The resulting long-lasting sustained-release microspheres of rasagilan dihydroxynaphthyl acid contain rasagilan dihydroxynaphthyl acid and polylactic acid polymers, wherein the polylactic acid polymers are selected from one or more of lactide-glycolic acid copolymers, high molecular weight polylactic acid, and low molecular weight polylactic acid.

[0016] The lactide-glycolic acid copolymers mentioned therein are selected from one of PLGA752H (weight average molecular weight 13600 Da, intrinsic viscosity 0.19 dL / g), PLGA753H (34000 Da, 0.39 dL / g), PLGA653H (32500 Da, 0.38 dL / g), PLGA502H (14200 Da, 0.2 dL / g), PLGA503H (34700 Da, 0.4 dL / g), and PLGA504H (46500 Da, 0.5 dL / g), all of which have carboxyl termini; The high molecular weight polylactic acid is selected from one of uncapped PLA202H (13600 Da, 0.19 dL / g) and uncapped PLA203H (26000 Da, 0.3 dL / g); The low molecular weight polylactic acid is selected from one of the following: carboxyl-terminated racemic PDLLA2800 (2800 Da, 0.03 dL / g), carboxyl-terminated racemic PDLLA4000 (4000 Da, 0.04 dL / g), and carboxyl-terminated racemic PDLLA6000 (6000 Da, 0.06 dL / g).

[0017] More preferably, the polylactic acid polymer is selected from a mixture of high molecular weight polylactic acid and low molecular weight polylactic acid.

[0018] In the most preferred embodiment, rasagiline dihydroxynaphthyl acid accounts for 17% of the total weight of the microspheres, PLA203H accounts for 66% of the total weight of the microspheres, and PDLLA6000 accounts for 17% of the total weight of the microspheres.

[0019] The final obtained long-acting sustained-release microspheres of rasagiline dihydroxynaphthyl acid have a particle size range of 10-200 μm.

[0020] The inventors also provided a method for preparing the above-mentioned long-acting sustained-release microspheres of rasagiline dihydroxynaphthyl acid, which specifically includes the following steps: (1) Dissolve rasagilan dihydroxynaphthyl acid and polylactic acid polymers in an organic solvent in a certain proportion to form a clear and transparent solution as the oil phase; (2) Prepare a polyvinyl alcohol solution of a certain concentration and control the temperature at 2-25℃ as the aqueous phase; (3) Under the action of high-speed shearing, the oil phase is dispersed into the aqueous phase to form an O / W emulsion; (4) During curing, sodium dihydrogen phosphate or potassium dihydrogen phosphate solution is selectively added slowly to the O / W emulsion obtained in step (3), and the temperature is controlled at 5-40℃. The mixture is mechanically stirred at 250 rpm for 4-5 hours to remove organic solvents by evaporation. After curing, the mixture is collected, washed with purified water 5-6 times, and then freeze-dried under vacuum for 46-48 hours. The freeze-drying temperature is controlled at -30℃ to 20℃ to obtain microspheres.

[0021] Furthermore, the organic solvent in step (1) is composed of a polar solvent and a non-polar solvent, with a volume ratio of (1:1) to (1:3); wherein the polar solvent is selected from one or more mixed solvents of dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), and N,N-dimethylacetamide (DMA); the non-polar solvent is dichloromethane (DCM); and the ratio of rasagiline dihydroxynaphthyl acid to the organic solvent is in the range of 50 mg / mL to 110 mg / mL.

[0022] The mass concentration of the polyvinyl alcohol solution in step (2) is 0.1%-2%, preferably 1.2%, and the solvent is water.

[0023] The shearing conditions in step (3) are to shear for 11-13 seconds at a rotation speed of 1000-2000 rpm, preferably 12 seconds. Too long or too short a time will result in the microspheres being too large or too small.

[0024] The volume ratio of the organic solvent in step (1) to the polyvinyl alcohol solution in step (2) is (1:50)-(1:125), and more preferably 1:110.

[0025] In step (4), the concentration of the sodium dihydrogen phosphate or potassium dihydrogen phosphate solution is 0.01-0.6 mol / L, more preferably sodium dihydrogen phosphate solution with a concentration of 0.6 mol / L; the volume ratio of the organic solvent to the sodium dihydrogen phosphate or potassium dihydrogen phosphate solution is (1:10)-(1:25), preferably 1:15. Sodium dihydrogen phosphate or potassium dihydrogen phosphate, as a pH adjuster, can reduce the solubility of rasagiline dihydroxynaphthyl acid in the aqueous phase, inhibit its diffusion into the aqueous phase, and improve the encapsulation efficiency.

[0026] The curing process described in step (4) is controlled at 5-25℃ for 1 hour and 25-40℃ for 3 hours. A more preferred curing process is 10℃ for 1 hour and 25℃ for 3 hours.

[0027] Compared with the prior art, the technical effects achieved by the present invention are as follows: (1) In this invention, rasagiline is prepared into rasagiline dihydroxynaphthyl acid, which has a significantly reduced solubility compared to rasagiline free base or other acid salts. Sodium dihydrogen phosphate or potassium dihydrogen phosphate solution is added to the sheared emulsion to adjust the pH of the aqueous phase, thereby reducing the solubility of rasagiline dihydroxynaphthyl acid in the aqueous phase and further inhibiting drug diffusion. This achieves high drug loading and high encapsulation efficiency, with a drug loading of over 14% and an encapsulation efficiency of over 80%. When injected into the body via intramuscular injection, it has a good sustained-release effect and can maintain a stable and effective blood drug concentration for a long time.

[0028] (2) Compared with traditional microsphere preparation, this invention uses low molecular weight PDLLA as an endogenous porogen, and the acidic products generated by its degradation can accelerate the degradation of high molecular weight PLA. By controlling the molecular weight and addition ratio of low molecular weight PDLLA, the drug release rate can be precisely adjusted, and a stable release for four weeks can be achieved.

[0029] (3) The present invention found that by precisely adjusting the temperature and time during curing, the evaporation rate of organic solvents can be reduced, which is conducive to the formation of a dense surface of microspheres, reducing drug burst release, and ensuring stable drug release, which can maintain a stable and effective blood drug concentration for a long time.

[0030] (4) The present invention uses a single emulsion solvent evaporation method to prepare long-acting sustained-release microspheres of rasagiline dihydroxynaphthyl acid. The process is simple, the results are stable and reproducible, and it can be industrialized. In addition, the use of organic solvents can be greatly reduced during the preparation process, which reduces the risk of biocompatibility. It is applicable to a wider range of people and has greater advantages in clinical administration safety and flexibility. Attached Figure Description

[0031] Figure 1 The ¹H-NMR spectrum of rasagiline dihydroxynaphthyl acid prepared in Example 1 is shown; Figure 2 The ¹H-NMR spectrum of rasagiline mesylate is shown; Figure 3 The infrared spectra of disodium dihydroxynaphthyl acid monohydrate, rasagiline dihydroxynaphthyl acid, and rasagiline mesylate from Example 1 are shown. Figure 4 The X-ray powder diffraction (PXRD) patterns of disodium dihydroxynaphthyl salt monohydrate, rasagiline dihydroxynaphthyl acid, and rasagiline mesylate in Example 1 are shown. Figure 5 Differential scanning calorimetry (DSC) plots of rasagilan dihydroxynaphthyl acid microspheres, blank microspheres, and rasagilan dihydroxynaphthyl acid microspheres are shown in Example 1. Figure 6 Microscopic images of the bis(hydroxynaphthyl) rasagiline microspheres prepared in Example 20 are shown; Figure 7 Scanning electron microscope images of rasagiline dihydroxynaphthyl acid microspheres prepared in Example 20 are shown. Figure 8 Release curves of the rasagiline dihydroxynaphthyl acid microspheres prepared in Examples 4, 8 and 16 are shown; Figure 9 Release curves of the rasagiline dihydroxynaphthyl acid microspheres prepared in Examples 12 and 15 are shown; Figure 10 Release curves of the rasagiline dihydroxynaphthyl acid microspheres prepared in Examples 19-21 are shown; Figure 11 The release curves of the rasagiline mesylate microspheres prepared in Comparative Example 1 are shown. Figure 12 The release curves of the rasagiline microspheres prepared in Comparative Example 2 are shown. Figure 13 The accelerated release curves of the rasagiline mesylate microspheres prepared in Comparative Example 3 are shown. Detailed Implementation

[0032] Other materials used in this invention, unless otherwise stated, are commercially available. Other terms used in this invention, unless otherwise specified, generally have the meanings commonly understood by those skilled in the art. The invention is further described in detail below with reference to specific embodiments and data. The following embodiments are merely illustrative and not intended to limit the scope of the invention in any way.

[0033] The rasagiline and rasagiline mesylate used were sourced from Nanjing Kangmanlin Biomedical Technology Co., Ltd. The disodium dihydroxynaphthyl salt monohydrate used was sourced from Shanghai Aladdin Biochemical Technology Co., Ltd. The lactide-glycolic acid copolymer (PLGA) used was sourced from Evonik. The high molecular weight polylactic acid (PLA202H, PLA203H) used was sourced from Evonik. The low molecular weight polylactic acid used was sourced from Jinan Daigang Bioengineering Co., Ltd. The dichloromethane (DCM) and dimethyl sulfoxide (DMSO) used were sourced from Sinopharm Chemical Reagent Co., Ltd. The hot-melt analytical grade polyvinyl alcohol (PVA, degree of polymerization 1700±50) used was sourced from Shanghai Yingjia Industrial Development Co., Ltd. The sodium dihydrogen phosphate and potassium dihydrogen phosphate used were sourced from Tianjin Yongda Chemical Reagent Co., Ltd.

[0034] Example 1: A long-acting sustained-release microsphere of rasagiline dihydroxynaphthyl acid and its preparation method, the specific steps of which are as follows: (1) Weigh 6.07 g (22.7 mmol) of rasagiline mesylate and 4.91 g (11.35 mmol) of disodium bis(hydroxynaphthyl) sodium salt monohydrate, add them to 60 mL of distilled water respectively, and stir at room temperature until completely dissolved; at room temperature, slowly add the disodium bis(hydroxynaphthyl) sodium salt monohydrate solution to the rasagiline mesylate solution, continue stirring for 1 h, and precipitate will precipitate; after filtration, take the precipitate and vacuum dry at 40 °C for 48 h to obtain rasagiline bis(hydroxynaphthyl) sodium salt monohydrate. Weigh 102 mg of rasagiline dihydroxynaphthyl acid and 500 mg of PLGA753H, add 2 mL of mixed organic solvent (DCM:DMSO=3:1, volume ratio), dissolve to obtain a clear solution, which is the oil phase; (2) Prepare 250 mL of a 1.2% polyvinyl alcohol solution and control the temperature at 3-5℃ as the aqueous phase; (3) Under the action of high-speed shearing, the oil phase is dispersed into the aqueous phase, the rotation speed is 1200 rpm, and the shearing time is 12s to prepare an O / W emulsion; (4) The O / W emulsion obtained in the above steps was mechanically stirred at 250 rpm for 4 h at 25 °C to remove the organic solvent; after solidification, it was collected, washed 5 times with purified water, and then freeze-dried under vacuum at -30 °C to 20 °C for 48 h to obtain microspheres.

[0035] Figure 1 The 1H NMR spectrum of rasagiline dihydroxynaphthyl acid prepared in step (1) is shown below: 1 HNMR (600 MHz, DMSO-d6) δ 8.22 (s, 2H), 8.18 (d, J = 8.7 Hz, 2H), 7.68 (d, J =8.0 Hz, 2H), 7.57 (d, J = 7.5 Hz, 2H), 7.34 (d, J = 4.2 Hz, 4H), 7.29 - 7.27(m, 2H), 7.17 - 7.15 (m, 2H), 7.04 (t, J = 7.2 Hz, 2H), 4.74 - 4.72 (m, 2H), 4.69 (s, 2H), 3.90 (s, 4H), 3.64 (s, 2H), 3.11 - 3.06(m, 2H), 2.89 - 2.84 (m, 2H), 2.45 - 2.38 (m, 2H), 2.16 - 2.11 (m, 2H). Analysis shows that δ 2.50 is the DMSO-d6 solvent peak; δ 8.22 is the CH signal peak of the naphthalene ring connected to the carboxyl group; δ 8.18 - 7.57 and δ 7.29 - 7.27 are the CH signal peaks of the naphthalene ring; δ 7.34 and δ 7.17 - 7.04 are the CH signal peaks of the benzene ring; δ 4.74 - 4.72 is the CH signal peak of the five-membered ring connected to NH; δ 4.69 is the CH2 signal peak connected to the naphthalene ring; δ 3.90 is the CH2 signal peak connected to NH; δ 3.64 is the H signal peak at the alkynyl terminus; δ 3.11 - 2.11 is the signal peak of CH2 connected to the benzene ring on the five-membered ring.

[0036] Figure 2 The 1H NMR spectrum of rasagiline mesylate is shown below: 1H NMR (600 MHz, DMSO-d6) δ 9.44 (s, 1H), 7.60 (d, J = 7.6 Hz, 1H), 7.40 - 7.36 (m, 2H), 7.31 (t, J = 7.9 Hz, 1H), 4.82 -4.80 (m, 1H), 4.01 (d, J = 2.2 Hz, 2H), 3.79 (m, J= 2.4 Hz, 1H), 3.13 - 3.08(m, 1H), 2.91 - 2.86 (m, 1H), 2.47 - 2.41(m, 1H),2.30 (s, 3H), 2.21 - 2.16 (m, (1H). Analysis of the 1H-NMR spectrum of rasagiline methanesulfonate reveals the following peaks: δ 2.50 is the DMSO-d6 solvent peak; δ 9.44 is the OH signal peak on the sulfonic acid group; δ 7.60-7.31 is the signal peak of the four H atoms on the benzene ring; δ 4.82-4.80 is the NH signal peak; δ 4.01 is the CH2 signal peak connected to the NH group; δ 3.79 is the CH signal peak on the five-membered ring connected to the NH group; δ 3.13-2.86 is the CH2 signal peak connected to the benzene ring on the five-membered ring; δ 2.30 is the CH3 signal peak on the sulfonic acid group; and δ 2.47-2.41 and δ 2.21-2.16 are the CH2 signal peaks near the NH group on the five-membered ring.

[0037] Based on the above ¹H-NMR chemical shift assignments, the δ 8.22 peak in rasagiline dihydroxynaphthyl acid represents a CH signal peak on the naphthalene ring connected to the carboxyl group, with two H atoms, indicating two naphthalene rings corresponding to one disodium dihydroxynaphthyl acid salt; the δ 7.34 and δ 7.17-7.04 peaks represent CH signal peaks on the benzene ring, with eight H atoms, indicating two benzene rings corresponding to two rasagilines; and a comparison with... Figure 2 The chemical shifts and integral areas of characteristic protons in the ¹H-NMR spectrum of rasagiline mesylate, combined with the reaction mechanism of disodium dihydroxynaphthate monohydrate and rasagiline mesylate, indicate that rasagiline mesylate reacts with disodium dihydroxynaphthate monohydrate in a 1:2 molar ratio to produce rasagiline mesylate.

[0038] Figure 3 The infrared spectra of disodium dihydroxynaphthyl acid monohydrate, rasagiline dihydroxynaphthyl acid, and rasagiline mesylate are shown. Analysis reveals that rasagiline mesylate and rasagiline dihydroxynaphthyl acid have a peak density at 3200 cm⁻¹. -1 Absorption peaks of primary amine (NH4) stretching vibrations were observed in the vicinity of the target area; at 2100 cm⁻¹... -1Near the same point, all three showed absorption peaks due to the alkynyl (C≡C) stretching vibration. Rasagilan dihydroxynaphthyl acid and its disodium hydrate monohydrate showed absorption peaks due to the methylene (CH₂) stretching vibration around 2940 cm⁻¹; and at 1640 cm⁻¹... -1 and 1550cm -1 Absorption peaks due to benzene ring skeletal vibrations were observed in the vicinity. Additionally, rasagiline mesylate showed an absorption peak at 1153.8 cm⁻¹. -1 An absorption peak for the stretching vibration of the sulfonic acid group (S=O) bond appears at 1046.5 cm⁻¹. -1 An absorption peak of (SO) bond stretching vibration of sulfonic acid group was observed at the sulfonic acid group, while the characteristic absorption peak of rasagilan dihydroxynaphthyl acid was not observed. By analyzing the differences and correspondences of the characteristic absorption peaks, the successful formation and structural correctness of rasagilan dihydroxynaphthyl acid were verified.

[0039] Figure 4 The images show the X-ray powder diffraction (PXRD) patterns of disodium dihydronaphthyl acid monohydrate, rasagiline dihydronaphthyl acid, and rasagiline mesylate. The prepared rasagiline dihydronaphthyl acid showed no obvious sharp diffraction peaks and did not overlap with the characteristic peaks of disodium dihydronaphthyl acid monohydrate and rasagiline mesylate, indicating that it was an amorphous substance. This suggests that rasagiline dihydronaphthyl acid was generated by a complex arrangement of the two drugs, rather than a simple physical mixture.

[0040] Figure 5 Differential scanning calorimetry (DSC) curves of rasagiline dihydroxynaphthyl acid microspheres, blank microspheres (prepared using the above method without the addition of rasagiline dihydroxynaphthyl acid), and rasagiline dihydroxynaphthyl acid were presented. Rasagiline dihydroxynaphthyl acid exhibited a distinct melting peak at 165.4 °C; the blank PLA microspheres showed a glass transition temperature of 51.0 °C; the DSC curve of the rasagiline dihydroxynaphthyl acid microspheres showed both a glass transition temperature of 51.0 °C, consistent with the blank microspheres, and a drug melting peak at 164.8 °C (slightly shifted compared to rasagiline dihydroxynaphthyl acid). These results indicate that the drug is dispersed in the PLA carrier matrix, providing a thermodynamic basis for the compatibility and dispersion state of the drug and carrier material.

[0041] Examples 2-6: A long-acting sustained-release microsphere of rasagiline dihydroxynaphthyl acid and its preparation method, the specific steps of which are as follows: Long-lasting sustained-release microspheres of rasagilan bishydroxynaphthyl acid were prepared according to the specifications, dosages, and curing conditions of each component in Table 1. The specific preparation method is the same as in Example 1.

[0042] Table 1 Specifications, dosages, and curing conditions of each component in Examples 2-6 .

[0043] Example 7: A long-acting sustained-release microsphere of rasagiline dihydroxynaphthyl acid and its preparation method, the specific steps of which are as follows: (1) Weigh 133 mg of rasagiline dihydroxynaphthyl acid (prepared according to step (1) of Example 1), 64 mg of PLGA752H and 576 mg of PLA202H, add 2 mL of mixed organic solvent (DCM:DMSO=3:1, volume ratio), dissolve to obtain a clear solution, which is used as the oil phase; (2) Prepare 250 mL of a 1.2% polyvinyl alcohol solution and control the temperature at 3-5℃ as the aqueous phase; (3) Under the action of high-speed shearing, the oil phase is dispersed into the aqueous phase, the rotation speed is 1200 rpm, and the shearing time is 12s to prepare an O / W emulsion; (4) Slowly add 50 mL of 0.6 mol / L sodium dihydrogen phosphate solution to the O / W emulsion obtained in step (3), and mechanically stir at 250 rpm for 4 h at 25 °C to remove organic solvent by evaporation; collect after solidification in the same way as in Example 1, wash 5 times with purified water, and freeze dry under vacuum at -30 °C to 20 °C for 48 h to obtain microspheres.

[0044] Examples 8-10: A long-acting sustained-release microsphere of rasagiline dihydroxynaphthyl acid and its preparation method, the specific steps of which are as follows: Long-lasting sustained-release microspheres of rasagilan bishydroxynaphthyl acid were prepared according to the specifications, dosages, and curing conditions of each component in Table 2. The specific preparation method is the same as in Example 7.

[0045] Table 2 Specifications, dosages, and curing conditions of each component in Examples 8-10 .

[0046] Example 11 A long-acting sustained-release microsphere of rasagiline dihydroxynaphthyl acid and its preparation method, the specific steps of which are as follows: (1) Weigh 144 mg of rasagiline dihydroxynaphthyl acid (prepared according to step (1) of Example 1) and 700 mg of PLA202H, add 2 mL of mixed organic solvent (DCM:DMSO=3:1, volume ratio), dissolve to obtain a clear solution, which is the oil phase; (2) Prepare 250 mL of a 1.2% polyvinyl alcohol solution and control the temperature at 3-5℃ as the aqueous phase; (3) Under the action of high-speed shearing, the oil phase is dispersed into the aqueous phase, the rotation speed is 1200 rpm, and the shearing time is 12s to prepare an O / W emulsion; (4) Slowly add 50 mL of 0.6 mol / L sodium dihydrogen phosphate solution to the O / W emulsion obtained in step (3), and mechanically stir at 250 rpm for 4 h at 25 °C to remove organic solvent by evaporation; collect after solidification in the same way as in Example 1, wash 5 times with purified water, and freeze dry under vacuum at -30 °C to 20 °C for 48 h to obtain microspheres.

[0047] Examples 12-16: A long-acting sustained-release microsphere of rasagiline dihydroxynaphthyl acid and its preparation method, the specific steps of which are as follows: Long-acting sustained-release microspheres of rasagilan bishydroxynaphthyl acid were prepared according to the specifications, dosage and curing conditions of each component in Table 3. The specific preparation method is the same as in Example 11.

[0048] Table 3 Specifications, dosages, and curing conditions of each component in Examples 12-16 .

[0049] Example 17 A long-acting sustained-release microsphere of rasagiline dihydroxynaphthyl acid and its preparation method, the specific steps of which are as follows: (1) Weigh 144 mg of rasagiline dihydroxynaphthyl acid (prepared according to step (1) of Example 1), 560 mg of PLA202H and 140 mg of PDLLA6000, add 2 mL of mixed organic solvent (DCM:DMSO=3:1, volume ratio), dissolve to obtain a clear solution, which is the oil phase; (2) Prepare 250 mL of a 1.2% polyvinyl alcohol solution and control the temperature at 15℃ as the aqueous phase; (3) Under the action of high-speed shearing, the oil phase is dispersed into the aqueous phase, the rotation speed is 1200 rpm, and the shearing time is 12s to prepare an O / W emulsion; (4) Slowly add 50 mL of 0.6 mol / L sodium dihydrogen phosphate solution to the O / W emulsion obtained in step (3), stir at 250 rpm for 1 h at 15 °C, then slowly raise the temperature to 25 °C and stir at 250 rpm for 3 h to evaporate and remove organic solvent; collect after solidification in the same way as in Example 1, wash 5 times with purified water, and freeze dry under vacuum at -30 °C to 20 °C for 48 h to obtain microspheres.

[0050] Examples 18-21: A long-acting sustained-release microsphere of rasagiline dihydroxynaphthyl acid and its preparation method, the specific steps of which are as follows: Long-lasting sustained-release microspheres of rasagiline dihydroxynaphthyl acid were prepared according to the specifications, dosages, and curing conditions of each component in Table 4. The specific preparation method is the same as in Example 17.

[0051] Table 4. Specifications, dosages, and curing conditions of each component in Examples 18-21 Based on the above embodiments and characterization results (such as Examples 1-4), it can be seen that the PLGA microsphere encapsulation efficiency in Examples 1-6 meets the requirements, but the release cycle is relatively short (Example 4, Figure 8 This does not meet the requirements of practical applications.

[0052] The encapsulation efficiency of the high molecular weight PLA microspheres in Examples 7-10 reached 80% after the addition of disodium hydrogen phosphate, but the slow degradation of high molecular weight PLA resulted in a release period of seven weeks (Example 12). Figure 9 The release cycle of PLGA microspheres is too long, while that of PLGA microspheres is short. Introducing a mixture of PLGA and PLA results in a suitable cycle, but the release is not stable (Example 8). Figure 8 ), and it does not meet the requirements.

[0053] Examples 11-16 contain mixed microspheres of low molecular weight PDLLA and high molecular weight PLA, in which the release rate of PDLLA2800 mixed with high molecular weight PLA is too fast (Example 15). Figure 9 While PDLLA6000 mixed with high molecular weight PLA has a moderate release rate, capable of releasing for four weeks, its release on the first day is large, still insufficient to meet the requirements (Example 16). Figure 8 ).

[0054] Examples 17-21: Adjusting the curing temperature to 5-15℃ for 1 hour and 25℃ for 3 hours reduces the evaporation rate of the organic solvent, decreasing the release amount on the first day and ensuring stable release throughout the four-week period. Figure 10 The requirements can be met. Therefore, the technical solutions of Examples 19-21 are considered as feasible preferred solutions, with Example 20 being the optimal solution.

[0055] Comparative Example 1: Preparation of Rasagiline Mesylate Microspheres by Monoemulsion Method Rasagiline mesylate microspheres were prepared according to the literature of Marcos Fernández et al., and the steps are as follows: (1) Dissolve 400mg PLGA502H in 1mL dichloromethane, mix using a vortex mixer, then add 40mg pulverized rasagiline methanesulfonate, disperse evenly by vortex stirring and further ultrasonic treatment to form an organic phase; (2) Adjust the pH of a 1% polyvinyl alcohol solution to 10 and take 5 mL as the aqueous phase; (3) Using the Polytron system, the organic phase and the aqueous phase were emulsified at 2500 rpm for 60 s to form an O / W emulsion; (4) Immediately pour the obtained emulsion into 100 mL of 0.1% (w / v) PVA solution (pH=10) containing 5% sodium chloride, stir continuously at 400 rpm for 3 h at room temperature to evaporate and remove organic solvent; collect after solidification, wash 5 times with purified water, and freeze dry under vacuum for 48 h to obtain microspheres.

[0056] The drug loading and encapsulation efficiency of the drug prepared by this process were 4.8% and 52.8%, respectively, which are relatively low. Secondly, as... Figure 11As shown, the release cycle of the microspheres is short, only two weeks, failing to achieve the ideal long-term release target, and there is a significant burst release phenomenon (about 15% is released within 1 day).

[0057] Comparative Example 2: Preparation of Rasagilan Microspheres Rasagilan microspheres were prepared according to the method described in patent KR20220111086, with the following steps: (1) Dissolve 2.208 g of polylactic acid (0.32 dL / g) and 0.192 g of rasagiline in 4.100 g of dichloromethane as the first oil phase (polymer concentration: 35%), and dissolve 1.472 g of polylactic acid (0.23 dL / g) and 0.128 g of rasagiline in 2.208 g of dichloromethane as the second oil phase (polymer concentration: 40%). (2) Prepare 800 mL of a 1% polyvinyl alcohol aqueous solution at a controlled temperature of 10°C as the aqueous phase; (3) Under the action of high-speed shearing, the oil phase is dispersed into the aqueous phase, the rotation speed is 1200 rpm, and the shearing time is 12s to prepare an O / W emulsion; (4) The O / W emulsion prepared in the above steps was stirred at low speed at 40°C for 4 hours to remove organic solvent by evaporation; after solidification, it was collected, washed 5 times with purified water, and freeze-dried under vacuum for 48 hours to obtain microspheres. The encapsulation efficiency and in vitro release rate of the Rasagilan microspheres were investigated.

[0058] The microspheres prepared in Comparative Example 2 had a theoretical drug loading of only 8%, but the actual drug loading was only 3.5-5.0%, resulting in an excessively low encapsulation efficiency of only 43.75%-62.5%. This does not comply with the guidelines for microparticle formulations in the 2025 edition of the Chinese Pharmacopoeia (9014), which states that the encapsulation efficiency of microparticle formulations should generally not be lower than 80%. Furthermore, if... Figure 12 As shown, it can be seen that it can only be released steadily for three weeks, with a sudden release on the first day.

[0059] Comparative Example 3: Preparation of Rasagiline Mesylate Microspheres by Double Emulsion Method Rasagiline mesylate microspheres were prepared according to the method described in patent CN112190553B, with the following steps: (1) Dissolve 30 mg of rasagiline mesylate in 0.6 mL of 2 wt% tannic acid solution to obtain the internal aqueous phase; (2) Dissolve 540 mg PLGA503H in 6 mL of dichloromethane to obtain the oil phase; (3) The internal aqueous phase and oil phase were sheared and mixed at 12000 rpm to obtain a primary emulsion. The primary emulsion was added to a continuous external aqueous phase containing 0.8% sodium chloride and 1% PVA by a peristaltic pump and homogenized and emulsified at 900 rpm for 10 min to form a secondary emulsion. (4) Stir at 300 rpm for 6 h at room temperature to remove organic solvent by evaporation. After solidification, collect the product, wash it 5 times with purified water, and freeze-dry it under vacuum for 48 h to obtain rasagiline mesylate microspheres.

[0060] Compared to the single-emulsion method, the double-emulsion method has advantages in scenarios such as encapsulating water-soluble drugs. However, the double-emulsion method involves more complex steps, a longer production cycle, and greater difficulty in maintaining stability during scale-up production, leading to issues such as large batch-to-batch variations and inconsistent quality. Furthermore, if... Figure 13 As shown, it can be seen that it can only accelerate and stably release in vitro for 120 hours, and cannot ensure its sustained-release effect under physiological conditions.

[0061] Experimental Example 1: Solubility Investigation of Rissagilan and its Salt Forms The equilibrium solubility of rasagiline, rasagiline mesylate, and rasagiline dihydroxynaphthyl acid prepared in step (1) of Example 1 in different media was determined by the shake-flask dissolution method at 37°C (referring to the General Chapter 9023 Solubility Measurement Guidelines of the Chinese Pharmacopoeia 2025). The results are shown in Table 5.

[0062] Table 5. Results of solubility study of rasagiline and its salt forms at 37℃ The results showed that the solubility of the bis(hydroxynaphthyl) rasagiline prepared in this invention was significantly reduced compared to other salt forms.

[0063] Experimental Example 2: Determination of drug loading and encapsulation efficiency of rasagiline dihydroxynaphthyl acid microspheres The drug loading and encapsulation efficiency of the rasagiline dihydroxynaphthyl acid microspheres prepared in Examples 1-21 and Comparative Examples 1-3 were determined using the following methods: Test solution: Weigh 20 mg of microspheres and place them in a 50 mL volumetric flask. Add 2 mL of DMSO to dissolve them. Sonicate for about 5 min until completely dissolved. Then, dilute to volume with 0.01 mol / L hydrochloric acid, shake well, and filter (PTFE, 0.22 μm, 25 mm). Discard 3 mL and collect the filtrate.

[0064] Reference solution: Weigh 20 mg of rasagiline, place it in a 100 mL volumetric flask, add 2 mL of acetonitrile to dissolve it, dilute to volume with water, shake well, dilute tenfold, filter (PTFE, 0.22 μm, 25 mm), discard 3 mL, and take the filtrate.

[0065] The drug loading and encapsulation efficiency of the microspheres were determined by HPLC (referencing Chinese Pharmacopoeia 2025, Part IV, General Chapter 9014). Chromatographic column: Sunniest RP-AQUA C18 reversed-phase column (4.6 mm × 250 mm, 5 μm); mobile phase: mobile phase A was acetonitrile:water = 90:10 (v / v), mobile phase B was 0.02 mol / L ammonium acetate solution, mobile phase A:mobile phase B = 60:40 (v / v); detection wavelength: 265 nm; column temperature: 25 ℃; flow rate: 1 mL / min; injection volume: 20 μL.

[0066] Experimental Results: The drug loading and encapsulation efficiency of the microspheres were calculated using the following formula: Theoretical drug loading (%) = (Prescription drug mass / Total prescription mass) × 100%; Actual drug loading (%) = (Material mass in microspheres / Total mass of microspheres) × 100%; Encapsulation efficiency (%) = Actual drug loading / Theoretical drug loading × 100%; The results of Examples 1-21 and Comparative Examples 1-3 are shown in Table 6.

[0067] Table 6 Results of drug loading and encapsulation efficiency determination of microspheres As can be seen from the results in Table 6, the microspheres prepared in this invention have the advantages of high drug loading and high encapsulation efficiency compared with the comparative example, meeting the requirement in the Chinese Pharmacopoeia that the encapsulation efficiency of microparticle formulations should generally not be less than 80%.

[0068] Experimental Example 3: In vitro release rate detection of rasagiline microspheres The in vitro drug release behavior of rasagiline microspheres prepared in Examples 1-21 and Comparative Examples 1-3 was studied using a water bath isothermal shaking method. The method is as follows: 20 mg of microsphere sample was weighed and dispersed in 30 mL of PBS buffer (pH 7.4, containing 0.1% Tween 80 and 0.05% cetyltrimethylammonium bromide). The suspension was placed in a water bath shaker at 37±2℃ and the release experiment was conducted at a shaking frequency of 100 rpm. Samples were taken periodically, allowed to stand for 30 min or centrifuged at 3000 rpm for 2 min, and 5 mL of release medium was taken each time (with an equal amount of fresh release medium added to maintain the leak conditions). The sample was filtered (PTFE, 0.22 μm, 25 mm), 3 mL was discarded, and the filtrate was collected. The drug concentration in the filtrate was determined by high performance liquid chromatography, and the cumulative release rate was calculated according to the formula.

[0069] In the formula: Q—Cumulative release rate (%); V—Volume of the release medium used, mL; C t —The concentration of the drug contained in the release medium was measured at the sampling time point t, in mg / mL; V1—Volume of each sample taken, mL; C—The concentration of the drug in the release medium measured before the sampling time point t, in mg / mL; M—Total weight of the microspheres added, mg; X — Drug loading of microspheres (%).

[0070] The results of the above microsphere in vitro release experiment are as follows: Figure 8-13 As shown.

[0071] Experimental Example 4: Particle Size Detection of Dihydroxynaphthyl Acid Rasagiline Microspheres The microspheres were dispersed in distilled water, and the particle size of the microspheres was determined using a laser particle size analyzer. The particle size determination results of Examples 1-21 are shown in Table 7.

[0072] Table 7. Results of particle size determination of rasagiline dihydroxynaphthyl acid microspheres The above results indicate that the preparation process of this application has good repeatability and uniformity, and the prepared microspheres have a relatively uniform particle size distribution.

[0073] Experimental Example 5: Morphological Observation of Dihydroxynaphthyl Acid Rasagiline Microspheres The shape, surface morphology and cross-sectional morphology of the dihydroxynaphthyl arazagilan microspheres prepared in Example 20 were observed using a scanning electron microscope (SEM). Before observation, the microspheres were sputtered with gold, and then the gold-sputtered microspheres were imaged by SEM.

[0074] Figure 6 Microscopic images of rasagiline microspheres with dihydroxynaphthyl acid are shown; Figure 7 Scanning electron microscope images of rasagiline microspheres with dihydroxynaphthyl acid are shown; The images show that these microspheres containing rasagiline dihydroxynaphthyl acid have smooth surfaces and are perfectly spherical. The rasagiline dihydroxynaphthyl acid is well encapsulated by a mixture of PLA and PDLLA and is uniformly distributed within the microspheres.

[0075] Results: In summary, the long-acting sustained-release microspheres of rasagiline dihydroxynaphthyl acid prepared in Examples 1-21 of this invention have a drug loading capacity of over 14%, an encapsulation efficiency of over 80%, and stable drug release, achieving stable release for four weeks. Furthermore, the preparation process is simple, the results are stable and reproducible, and it can be industrialized.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art can utilize the above technical content to make changes or modifications to create equivalent embodiments. Any simple modifications, equivalent changes, and modifications made to the above embodiments without departing from the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A long-acting, sustained-release microspheres of rasagiline embonate, characterized in that, The raw material comprises rasagiline embonate and polylactic acid polymer, wherein the rasagiline embonate accounts for 10%-40% of the total weight of the microspheres, and the polylactic acid polymer accounts for 60%-90% of the total weight of the microspheres; wherein the polylactic acid polymer is selected from a mixture of high molecular weight polylactic acid and low molecular weight polylactic acid, the high molecular weight polylactic acid is selected from one of PLA202H and PLA203H; and the low molecular weight polylactic acid is selected from one of PDLLA2800, PDLLA4000 and PDLLA6000.

2. The long-acting, sustained-release rasagiline propanediolate microspheres according to claim 1, wherein the microspheres are characterized by: The rasagiline embonate long-acting sustained-release microspheres comprise 17% of rasagiline embonate, 66% of PLA203H and 17% of PDLLA6000 by weight of the total microspheres.

3. The method of claim 1, wherein the long-acting, sustained-release microspheres of rasagiline embonate are prepared by the steps of: Specifically comprising the following steps: (1) dissolving the rasagiline embonate and the polylactic acid polymer in the organic solvent in proportion to form a clear and transparent solution as an oil phase; (2) preparing a polyvinyl alcohol solution with a certain concentration and controlling the temperature at 2-25℃ as an aqueous phase; (3) under the action of high-speed shearing, dispersing the oil phase into the aqueous phase to prepare an O / W emulsion; (4) during solidification, optionally slowly adding a sodium dihydrogen phosphate or potassium dihydrogen phosphate solution into the O / W emulsion prepared in step (3), controlling the temperature at 5-40℃, and mechanically stirring at a speed of 250 rpm for 4-5 h to volatilize and remove the organic solvent; after solidification, collecting, purifying and washing with water for 5-6 times, and vacuum freeze-drying for 46-48 h at a temperature of-30℃-20℃ to obtain the microspheres.

4. The method of claim 3, wherein the long-acting sustained-release microspheres of rasagiline pamoate are prepared by the steps of: The preparation method of the rasagiline embonate in step (1) is as follows: Dissolving the rasagiline mesylate and the embonate disodium salt monohydrate in distilled water respectively and stirring to dissolve at room temperature; then slowly adding the embonate disodium salt monohydrate solution into the rasagiline mesylate solution to react for 0.5-2 h to precipitate; after filtration, taking the precipitate to vacuum dry at 40℃ for 46-48 h to obtain the rasagiline embonate.

5. The method for preparing the long-acting sustained-release microspheres of rasagiline dihydroxynaphthyl acid according to claim 4, characterized in that, The molar ratio of the rasagiline mesylate to the embonate disodium salt monohydrate is 2:1-1.1, and the solid-liquid ratio of the rasagiline mesylate to the distilled water is 6.07 g:60 mL.

6. The method for preparing the long-acting sustained-release microspheres of rasagiline dihydroxynaphthyl acid according to claim 3, characterized in that, The organic solvent in step (1) is composed of a polar solvent and a non-polar solvent, and the volume ratio of the two is 1:1-1:3; wherein the polar solvent is selected from one or more of a mixture of dimethyl sulfoxide, N-methyl pyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide; the non-polar solvent is dichloromethane; and the proportion of the rasagiline embonate to the organic solvent is 50 mg / mL-110 mg / mL.

7. The method for preparing the long-acting sustained-release microspheres of rasagiline dihydroxynaphthyl acid according to claim 3, characterized in that, The mass concentration of the polyvinyl alcohol solution in step (2) is 0.1%-2%; the shearing condition in step (3) is shearing at a speed of 1000-2000 rpm for 11-13 s; and the volume ratio of the organic solvent in step (1) to the polyvinyl alcohol solution in step (2) is 1:50-1:

125.

8. The method for preparing the long-acting sustained-release microspheres of rasagiline dihydroxynaphthyl acid according to claim 3, characterized in that, The concentration of the sodium dihydrogen phosphate or potassium dihydrogen phosphate solution in step (4) is 0.01-0.6 mol / L, and the volume ratio of the organic solvent to the sodium dihydrogen phosphate or potassium dihydrogen phosphate solution is 1:10-1:25; and the solidification process in step (4) is controlled at 5-25 ℃ for 1 h and 25-40 ℃ for 3 h.

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