Sustained-release microspheres containing memantine or salt derivatives thereof and preparation method of sustained-release microspheres

Abstract

The invention provides sustained release microspheres containing memantine or salt derivatives thereof and a preparation method of the sustained release microspheres. The preparation method comprises the following steps: preparing an external water phase W2, dissolving a surfactant and an osmotic pressure regulator in ultrapure water, and regulating the pH value to a target pH value by using a pH regulator; preparing an oil phase O, dissolving memantine or a salt derivative thereof and a biocompatible polymer in an organic solvent, and carrying out vortex to dissolve the memantine or the salt derivative thereof and the biocompatible polymer; mixing the external water phase W2 with the oil phase O, and adding the mixture into a rapid membrane emulsifier to prepare an emulsion; and stirring, curing, washing and freeze-drying the emulsion to obtain the sustained-release microspheres containing memantine or the salt derivatives thereof. According to the invention, the medication compliance of the Alzheimer's disease patient can be effectively improved, the medication frequency of the patient is greatly reduced, and the repeated or worsened condition caused by the fluctuation of the blood concentration due to wrong taking and missed taking can be effectively avoided; meanwhile, the sustained-release microspheres for injection can effectively avoid adverse reaction of gastrointestinal tracts caused by oral administration, and have obvious clinical advantages.

Description

Technical Field

[0001] The invention relates to sustained-release microspheres containing memantine or its salt derivatives and a preparation method thereof, belonging to the technical field of medical preparations. Background Art

[0002] Alzheimer's disease (AD) is a degenerative disease of the central nervous system and the most common type of dementia in the elderly. It is a common disease in the elderly with an insidious onset and a slow and progressive course. It is mainly manifested by neuropsychiatric symptoms such as cognitive dysfunction, progressive memory impairment, language disorders, and personality changes. It may also rapidly deteriorate motor function, which has a serious impact on a person's social, occupational, and life functions. Late-stage patients lose their social skills and develop psychiatric symptoms such as paranoia, hallucinations, and delusions. They eventually become mutist, incontinent, and bedridden for a long time.

[0003] There is no drug that can cure Alzheimer's disease, but effective drug treatment can improve the patient's symptoms. The drugs approved for the first-line clinical treatment of Alzheimer's disease at home and abroad are mainly cholinesterase inhibitors and glutamate receptor antagonists. At present, no breakthrough has been made in the drug treatment of Alzheimer's disease. There are five drugs approved for marketing by the US Food and Drug Administration (FDA) for the treatment of Alzheimer's patients, namely tacrine, donepezil, rivastigmine (rivastigmine), galantamine and memantine. The first four drugs are all acetylcholinesterase inhibitors. Some Alzheimer's patients are not suitable for the use of cholinesterase inhibitors. Memantine is a glutamate receptor antagonist. Memantine is mainly used in the treatment of Alzheimer's disease in clinical practice. The memantine hydrochloride preparations currently marketed at home and abroad include ordinary tablets, oral solutions and sustained-release capsules. Although oral preparations are highly safe, easy to take, and easily accepted by patients, oral preparations of memantine hydrochloride need to be taken 1 to 2 times a day. For Alzheimer's patients, it is often difficult to take the medicine independently, and they are prone to taking the wrong dose, missing a dose, or even refusing to take the dose. When the disease progresses to a certain extent, the patient will also experience difficulty swallowing, which will eventually lead to discontinuation of treatment and further deterioration of the condition.

[0004] Therefore, there is an urgent need to develop a long-acting injection of memantine that can release drugs over a long period of time, so as to improve the medication compliance of Alzheimer's patients, greatly reduce the frequency of medication for patients, and effectively avoid the recurrence or deterioration of the disease caused by fluctuations in blood drug concentrations due to wrong or missed doses; at the same time, sustained-release microspheres for injection can effectively avoid gastrointestinal adverse reactions caused by oral administration, and have obvious clinical advantages. Summary of the invention

[0005] The object of the present invention is to provide a sustained-release microsphere containing memantine or its salt derivatives and a preparation method thereof, so as to reduce the number of administrations and reduce gastrointestinal adverse reactions.

[0006] To achieve the above object, the present invention provides a method for preparing sustained-release microspheres containing memantine or its salt derivatives, the preparation method comprising:

[0007] Prepare an external water phase W2, dissolve a surfactant and an osmotic pressure regulator in ultrapure water, and adjust the pH to a target pH using a pH regulator;

[0008] preparing an oil phase O, dissolving memantine or its salt derivative and a biocompatible polymer in an organic solvent, and vortexing to dissolve them;

[0009] After mixing the external water phase W2 with the oil phase O, the mixture was added into a rapid membrane emulsifier to prepare an emulsion;

[0010] The emulsion is stirred, solidified, washed and freeze-dried to obtain sustained-release microspheres containing memantine or its salt derivatives.

[0011] As a further improvement of the present invention, the memantine salt derivative comprises at least one or a combination of hydrochloride, pamoate, p-toluenesulfonate, benzoate or fumarate.

[0012] As a further improvement of the present invention, when the memantine salt derivative is a hydrochloride, the preparation method comprises:

[0013] Anhydrous ethanol and ultrapure water were used to prepare the internal aqueous phase W1;

[0014] The biocompatible polymer is dissolved in an organic solvent and vortexed to dissolve it to prepare an oil phase O;

[0015] Dissolve a surfactant and an osmotic pressure regulator in ultrapure water, and adjust the pH to a target pH using a pH regulator to prepare an external aqueous phase W2;

[0016] Dissolving the memantine hydrochloride in the internal water phase W1;

[0017] The inner water phase W1 is added to the oil phase O to disperse and form colostrum; the colostrum is added to the outer water phase W2 to disperse and form a pre-emulsion, and then added to a rapid membrane emulsifier to prepare an emulsion;

[0018] The emulsion is stirred, solidified, washed and freeze-dried to obtain sustained-release microspheres containing memantine or its salt derivatives.

[0019] As a further improvement of the present invention, the method for obtaining sustained-release microspheres containing memantine or its salt derivatives after stirring, solidifying, washing and freeze-drying the emulsion comprises:

[0020] The emulsion is rapidly solidified into balls by evaporating the solvent;

[0021] The sustained-release microspheres are obtained by washing the microspheres with an aqueous solution or an aqueous solution with an osmotic pressure regulator added thereto and drying them.

[0022] As a further improvement of the present invention, the surfactant is at least one of PVA, Tween, SDS, SDBS, and OP-10.

[0023] As a further improvement of the present invention, the osmotic pressure regulator is sodium chloride or potassium chloride; the pH regulator is sodium hydroxide or sodium bicarbonate.

[0024] As a further improvement of the present invention, the biocompatible polymer is at least one of PLGA, PELA, PLA, PHA, and PCL.

[0025] As a further improvement of the present invention, the organic solvent is one of chloroform, dichloromethane, ethyl acetate, acetone, acetonitrile, anhydrous ethanol, anhydrous methanol or any combination thereof.

[0026] Another object of the present invention is to provide a sustained-release microsphere containing memantine or its salt derivatives prepared by the above preparation method.

[0027] To achieve the above object, the present invention provides a sustained-release microsphere containing memantine or its salt derivatives, wherein the sustained-release microsphere containing memantine or its salt derivatives is prepared by the above-mentioned method for preparing sustained-release microsphere containing memantine or its salt derivatives.

[0028] As a further improvement of the present invention, the sustained-release microspheres containing memantine or its salt derivatives have a particle size of 10 to 30 μm and a drug loading of 1.5% to 20%.

[0029] The beneficial effects of the present invention are as follows: compared with the prior art, the present invention provides a sustained-release microsphere containing memantine or its salt derivatives and a preparation method thereof, which can fill the gap of memantine sustained-release microspheres at home and abroad. Moreover, it can be known from the above-mentioned in vitro cumulative release experiment and SD rat single-dose pharmacokinetic test that the sustained-release microspheres have a certain sustained-release effect in vivo, which can reduce the gastrointestinal side effects often encountered in traditional oral medications and improve the compliance of patients with Alzheimer's disease to maximize the therapeutic effect, thereby meeting the needs of the market. By injecting sustained-release microspheres containing memantine or its salt derivatives, the patient's compliance can be increased, eliminating the inconvenience of daily oral administration. In addition, the sustained-release microspheres of the present invention have a simple preparation method and can be prepared in large quantities in a short time. Moreover, in the preparation process, except for adding surfactants, osmotic pressure regulators, biocompatible polymers, and pH regulators, no other excipients are added, the operation is simple, the cost is low, the decomposition products have no toxic side effects in vivo, the safety performance is high, and the side effects are small. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is a schematic diagram of the preparation process of sustained-release microspheres containing memantine or its salt derivatives in a preferred embodiment of the present invention;

[0031] Figure 2 is a light microscopic image of the sustained-release microspheres containing memantine hydrochloride prepared in Example 1 of the present invention;

[0032] Figure 3 is an electron micrograph of the sustained-release microspheres containing memantine prepared in Example 2 of the present invention;

[0033] Figure 4 is an electron micrograph of the sustained-release microspheres containing memantine prepared in Example 3 of the present invention;

[0034] Figure 5 is an electron micrograph of the sustained-release microspheres containing memantine p-toluenesulfonate prepared in Example 4 of the present invention;

[0035] Figure 6 is an electron micrograph of the sustained-release microspheres containing memantine prepared in Example 5 of the present invention;

[0036] Figure 7 is an electron micrograph of the sustained-release microspheres containing memantine prepared in Example 6 of the present invention;

[0037] Figure 8 The in vitro cumulative release curves of the memantine-containing sustained-release microspheres prepared in Examples 3 and 6 of the present invention;

[0038] Fig. 9 Pharmacokinetic test curves of the sustained-release microspheres containing memantine prepared in Examples 3, 4 and 6 of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] It should be noted here that in order to avoid obscuring the present invention due to unnecessary details, only components and / or processing steps closely related to the scheme of the present invention are shown in the drawings, while other details that are not very relevant to the present invention are omitted.

[0041] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0042] See also Figure 1As shown, the present invention provides a method for preparing sustained-release microspheres containing memantine or its salt derivatives, comprising the following steps:

[0043] Prepare an external water phase W2, dissolve a surfactant and an osmotic pressure regulator in ultrapure water, and adjust the pH to a target pH using a pH regulator;

[0044] preparing an oil phase O, dissolving memantine or its salt derivative and a biocompatible polymer in an organic solvent, and vortexing to dissolve them;

[0045] After the external water phase W2 is mixed with the oil phase O, they are added into a rapid membrane emulsifier to prepare an emulsion. By using the rapid membrane emulsification technology, the particle size of the prepared sustained-release microspheres containing memantine or its salt derivatives is controllable and uniform, which solves the problem of poor reproducibility between batches, saves production costs, and the preparation process is stable and feasible, which is easy to mass produce.

[0046] The emulsion is stirred, solidified, washed and freeze-dried to obtain sustained-release microspheres containing memantine or its salt derivatives.

[0047] Further, the memantine salt derivative comprises at least one or a combination of hydrochloride, pamoate, p-toluenesulfonate, benzoate or fumarate. Among them, the hydrochloride containing memantine has a higher solubility in water, and the other memantine salt derivatives, for example, pamoate, p-toluenesulfonate, benzoate or fumarate containing memantine have a lower solubility in water.

[0048] When the solubility of the memantine salt derivative in water is low, it can be directly dissolved in an organic solvent with a biocompatible polymer to directly prepare the oil phase O. When the solubility of the memantine salt derivative in water is high, it needs to be first dissolved in the internal water phase to form colostrum, and then the colostrum is added to the oil phase O to disperse to form a pre-emulsion.

[0049] Specifically, when the memantine salt derivative is a hydrochloride, the preparation method comprises:

[0050] Anhydrous ethanol and purified water were used to prepare the internal aqueous phase W1;

[0051] The biocompatible polymer is dissolved in an organic solvent and vortexed to dissolve it to prepare an oil phase O;

[0052] Dissolve a surfactant and an osmotic pressure regulator in ultrapure water, and adjust the pH to a target pH using a pH regulator to prepare an external aqueous phase W2;

[0053] Dissolving the memantine hydrochloride in the internal water phase W1;

[0054] Adding the inner water phase W1 to the oil phase O to disperse and form colostrum; adding the colostrum to the outer water phase W2, and adding them to a rapid membrane emulsifier to prepare an emulsion;

[0055] The emulsion is stirred, solidified, washed and freeze-dried to obtain sustained-release microspheres containing memantine or its salt derivatives.

[0056] Furthermore, the method of obtaining sustained-release microspheres containing memantine or its salt derivatives after stirring, solidifying, washing and freeze-drying the emulsion comprises:

[0057] The emulsion is rapidly solidified into spheres by utilizing a solvent volatilization method; wherein the solvent volatilization method comprises at least one of a reduced pressure solidification method, a thin film evaporation method, a rotary evaporation method, and a normal pressure mechanical stirring method.

[0058] The sustained-release microspheres are obtained by washing the microspheres with an aqueous solution or an aqueous solution containing an osmotic pressure regulator (centrifugation, filtration, etc.), and drying.

[0059] Furthermore, the surfactant is at least one of PVA, Tween, SDS, SDBS, and OP-10. By adding a surfactant, the amphiphilic properties of the surfactant are utilized to stabilize the colostrum, which greatly reduces the risk of the API leaking from the external aqueous phase W2, improves drug embedding, and enables stable drug release.

[0060] Furthermore, the osmotic pressure regulator is sodium chloride or potassium chloride. Preferably, the concentration of the osmotic pressure regulator is 0.2-5.0 wt%. By adding the osmotic pressure regulator, the osmotic pressure difference between the external aqueous phase and the microspheres is reduced or eliminated, so that the liquid in the microspheres can be prevented from diffusing, the aqueous pores on the surface of the microspheres are prevented from forming, which leads to an accelerated release rate and prevents drug escape.

[0061] Furthermore, the pH regulator is sodium hydroxide or sodium bicarbonate. The pH of the external water phase W2 is adjusted to 9-11 using the pH regulator.

[0062] Furthermore, the biocompatible polymer is at least one of polylactic acid-co-glycolic acid (PLGA), polyethylene glycol-co-polylactic acid (PELA), polylactic acid (PLA), poly 3-hydroxyalkanoate (PHA), and poly-ε-caprolactone (PCL).

[0063] Furthermore, the organic solvent is one of chloroform, dichloromethane, ethyl acetate, acetone, acetonitrile, anhydrous ethanol, anhydrous methanol, or any combination thereof.

[0064] The present invention provides a sustained-release microsphere containing memantine or its salt derivatives. The sustained-release microsphere containing memantine or its salt derivatives is prepared by adopting the preparation method of the sustained-release microsphere containing memantine or its salt derivatives.

[0065] As a further improvement of the present invention, the sustained-release microspheres containing memantine or its salt derivatives have a particle size of 10 to 30 μm and a drug loading of 1.5% to 20%.

[0066] The following description lists several embodiments to more clearly illustrate the sustained-release microspheres containing memantine or its salt derivatives and the preparation method thereof of the present invention, but those skilled in the art will appreciate that they are not intended to be limited thereto.

[0067] Embodiment 1:

[0068] Anhydrous ethanol and purified water were used to prepare the inner aqueous phase W1, wherein anhydrous ethanol: purified water = 1:1.2. 0.3 g of hydrochloride containing memantine was weighed and dissolved in the inner aqueous phase W1. 1.2 g of PLGA (LA: GA = 75: 25) was weighed and dissolved in 10 mL of dichloromethane, vortexed to dissolve, and prepared as the oil phase O. 100 mL of 1.0% polyvinyl alcohol aqueous solution was prepared as the outer aqueous phase W2. The inner aqueous phase W1 was added to the oil phase O and homogenized at 22000 rpm in an ice water bath for 60 s, and added to the outer aqueous phase W2 to prepare a pre-emulsion by mechanical stirring for 30 s at a speed of 270 rpm. The pre-emulsion was poured into a rapid membrane emulsifier for emulsification and dispersion to obtain an emulsion, wherein the membrane tube pore size used was 20 μm. The emulsion was cured by negative pressure for 60 min at 38°C. After the curing was completed, the sustained-release microspheres containing memantine hydrochloride were obtained by washing and freeze-drying, and the optical microscope image thereof is shown as follows Figure 2 shown.

[0069] The particle size and uniformity of the sustained-release microspheres containing memantine hydrochloride prepared in Example 1 were tested using a Malvern 2000 laser particle size analyzer, the drug loading was tested using an Agilent HPLC, and the release was tested using a shaker and an Agilent HPLC. The microsphere particle size d(0.5) was measured to be 16 μm, the span was 0.8, and the drug loading was 1.82%.

[0070] pass Figure 2 The results of the test show that the particle size of the sustained-release microspheres containing memantine hydrochloride is small, which is convenient for injection, and the uniformity of the sustained-release microspheres is good, and the surface of the sustained-release microspheres is round and smooth without adhesion. Among them, the reason for the low drug loading in Example 1 may be that the solubility of memantine hydrochloride in anhydrous ethanol is easily soluble, and it dissolves in water. The addition of anhydrous ethanol to the inner aqueous phase increases the solubility of memantine hydrochloride. The organic solvent is removed in the solidification stage. The ethanol in the inner aqueous phase is removed during the solidification process, which will cause a large amount of raw materials to escape from the inside of the microspheres to the outer aqueous phase. Finally, after washing and freeze-drying, the actual amount of drug in the microspheres is reduced.

[0071] Example 2

[0072] Weigh 0.60g of memantine liquid and 2.4g of PLGA (LA:GA=50:50), dissolve in 10mL of dichloromethane to prepare oil phase O. Prepare 100mL of 1.0% polyvinyl alcohol aqueous solution as the external aqueous phase, add 3.3% sodium chloride, and adjust its pH to 11.00, which is the external aqueous phase W2. Add the oil phase O to the external aqueous phase W2 and prepare a pre-emulsion by mechanical stirring for 30s at a speed of 300rpm. Pour the pre-emulsion into a rapid membrane emulsifier for emulsification and dispersion to obtain an emulsion, wherein the membrane tube pore size used is 20μm. The emulsion is cured by negative pressure for 60min at 38°C. After the curing is completed, centrifugal washing and freeze-drying are performed to obtain memantine-containing sustained-release microspheres, the electron microscopy image of which is shown as follows Figure 3 shown.

[0073] The same method as in Example 1 was used for measurement. The measurement results showed that the particle size d(0.5) of the microspheres was 15 μm, the span was 0.8, and the drug loading was 8.3%.

[0074] pass Figure 3 The results of the test show that the particle size of the sustained-release microspheres containing memantine is small, which is convenient for injection, and the uniformity of the sustained-release microspheres is good, and the surface of the sustained-release microspheres is round and smooth without adhesion. In addition, the reason why the drug loading of the microspheres in Example 2 is higher than that in Example 1 may be that free memantine without hydrochloride is selected for microsphere embedding. The raw material drug is insoluble in water and miscible with dichloromethane, and can be directly used as an oil phase for microsphere preparation. Since the raw material drug is a liquid, in order to prevent the drug from escaping during the preparation process, a certain amount of inorganic salt is added to the aqueous phase to balance the osmotic pressure of the oil-water phase, which can effectively reduce the drug escape.

[0075] Example 3

[0076] Weigh 0.6g of liquid memantine and 2.4g of PLGA (LA:GA=50:50), dissolve in 10mL of dichloromethane to prepare oil phase O; prepare 100mL of 1.0% polyvinyl alcohol aqueous solution as external aqueous phase W2, add 3.3% sodium chloride, and adjust its pH to 11.00. Add oil phase O to external aqueous phase W2 and prepare pre-emulsion by mechanical stirring for 30s at a speed of 300rpm. Pour the pre-emulsion into a rapid membrane emulsifier for emulsification and dispersion to obtain an emulsion, wherein the membrane tube pore size used is 20μm. The emulsion is cured by negative pressure for 60min at 38°C. After the curing is completed, wash with 0.9% sodium chloride solution and freeze-dry to obtain sustained-release microspheres containing memantine, the electron microscope image of which is shown as follows. Figure 4 shown.

[0077] The same method as in Example 1 was used for measurement. The results showed that the particle size d(0.5) of the microspheres was 14 μm, the span was 0.7, and the drug loading was 13.5%.

[0078] pass Figure 4The results of the measurement show that the particle size of the sustained-release microspheres containing memantine is small, which is convenient for injection, and the uniformity of the sustained-release microspheres is good, and the surface of the sustained-release microspheres is round and smooth without adhesion. In addition, the preparation method of the microspheres in Example 3 is roughly the same as that in Example 2, except that a 0.9% sodium chloride solution is used to wash the microspheres in Example 3, which ultimately results in a higher drug loading in Example 3 than in Example 2. This is because the molecular weight of the sustained-release microspheres containing memantine is small, and when they are embedded in the microspheres and solidified, they cannot exist in a solid form, but in a liquid form. When the microspheres are washed with purified water, an osmotic pressure difference is formed, causing the drug to penetrate from the inside of the microspheres, and sodium chloride is used as an osmotic pressure regulator to wash the microspheres, which can effectively prevent the drug from escaping and increase the drug loading.

[0079] Example 4

[0080] Weigh 2.00 g of p-toluenesulfonate containing memantine and 3.00 g of PLGA (LA:GA=75:25), dissolve in 10 mL of dichloromethane to prepare oil phase O; prepare 100 mL of 1.0% polyvinyl alcohol aqueous solution as the external aqueous phase W2. Add the oil phase O to the external aqueous phase W2 and prepare a pre-emulsion by mechanical stirring for 30 seconds at a speed of 300 rpm. Pour the pre-emulsion into a rapid membrane emulsifier for emulsification and dispersion to obtain an emulsion, wherein the membrane tube pore size used is 40 μm. The emulsion is cured by negative pressure for 60 minutes at 38°C. After the curing is completed, wash with 0.9% sodium chloride solution and freeze-dry to obtain sustained-release microspheres containing memantine, the electron microscope image of which is shown as follows Figure 5 shown.

[0081] The same method as in Example 1 was used for measurement. The results showed that the particle size d(0.5) of the microspheres was 27 μm, the span was 0.9, and the drug loading was 18.6%.

[0082] pass Figure 5 It can be seen that the particle size of the sustained-release microspheres containing memantine is small, which is convenient for injection, and the uniformity of the sustained-release microspheres is good. The surface of the sustained-release microspheres is round and smooth without adhesion.

[0083] Comparing the measurement results of Example 4 and Example 3, it can be seen that the drug loading of the microspheres in Example 4 is higher than that in Example 3. This is because the API used in Example 3 is in liquid form. Although a certain amount of osmotic pressure regulator is added to effectively reduce drug escape during washing and collection, there is still a certain amount of drug escape. The API used in Example 4 is in solid form and exists in the microspheres in solid form after solidification, so the drug loading is relatively high.

[0084] Example 5

[0085] Weigh 1.00 g of solid memantine and 4.00 g of PLGA (LA:GA=50:50), dissolve in 10 mL of ethyl acetate to prepare oil phase O; prepare 100 mL of 1.0% polyvinyl alcohol aqueous solution as the external aqueous phase, and add 3.3% sodium chloride as the external aqueous phase W2. Add the oil phase O to the external aqueous phase W2 and prepare a pre-emulsion by mechanical stirring for 30 seconds at a speed of 300 rpm. Pour the pre-emulsion into a rapid membrane emulsifier for emulsification and dispersion to obtain an emulsion, wherein the membrane tube pore size used is 40 μm. The emulsion is cured by negative pressure for 60 minutes at 38°C. After the curing is completed, use purified water to wash and freeze-dry to obtain sustained-release microspheres containing memantine, the electron microscope image of which is shown as follows Figure 6 shown.

[0086] The measurement was carried out using the same method as in Example 1. The measurement results showed that d(0.5) was 27 μm, the span was 0.6, and the detected drug loading was 19.2%.

[0087] pass Figure 6 It can be seen that the particle size of the sustained-release microspheres containing memantine is small, which is convenient for injection, and the uniformity of the sustained-release microspheres is good. The surface of the sustained-release microspheres is round and smooth without adhesion. Figure 6 and Figure 4 It can be seen that the particle size of the memantine-containing microspheres prepared in Example 5 is larger than the particle size of the memantine-containing microspheres prepared in Example 3.

[0088] Comparing the measurement results of Example 5 and Example 3, it can be seen that the drug loading of the microspheres in Example 5 is higher than that in Example 3. This is because the API used in Example 3 is in liquid form. Although a certain amount of osmotic pressure regulator is added to effectively reduce drug escape during washing and collection, there is still a certain amount of drug escape. The API used in Example 5 is in solid form and exists in the microspheres in solid form after solidification, so the drug loading is relatively high.

[0089] Example 6

[0090] Weigh 1.00 g of solid memantine and 4.00 g of PLGA (LA:GA=50:50), dissolve in 10 mL of ethyl acetate to prepare oil phase O; prepare 50 mL of 1.0% polyvinyl alcohol aqueous solution as the external aqueous phase, and add 4.0% sodium chloride as the external aqueous phase W2. Add the oil phase O to the external aqueous phase W2 and prepare a pre-emulsion by mechanical stirring for 30 seconds at a speed of 300 rpm. Pour the pre-emulsion into a rapid membrane emulsifier for emulsification and dispersion to obtain an emulsion, wherein the membrane tube pore size used is 40 μm. The emulsion is cured by negative pressure for 60 minutes at 38°C. After the curing is completed, use purified water to wash and freeze-dry to obtain sustained-release microspheres containing memantine, the electron microscope image of which is shown as follows Figure 7 shown.

[0091] The same method as in Example 1 was used for measurement, and the test results showed that d(0.5) was 20 μm, span was 1.0, and the drug loading was 19.4%.

[0092] pass Figure 7 It can be seen that the particle size of the sustained-release microspheres containing memantine is small, which is convenient for injection, and the uniformity of the sustained-release microspheres is good. The surface of the sustained-release microspheres is round and smooth without adhesion. Figure 7 and Figure 4 It can be seen that the particle size of the memantine-containing microspheres prepared in Example 6 is larger than the particle size of the memantine-containing microspheres prepared in Example 3.

[0093] Comparing the measurement results of Example 6 and Example 3, it can be seen that the drug loading of the microspheres in Example 6 is higher than that in Example 3. This is because the API used in Example 3 is in liquid form. Although a certain amount of osmotic pressure regulator is added to effectively reduce drug escape during washing and collection, there is still a certain amount of drug escape. The API used in Example 6 is in solid form and exists in the microspheres in solid form after solidification, so the drug loading is relatively high.

[0094] Example 7

[0095] The memantine-containing sustained-release microspheres prepared in Example 3 and Example 6 were subjected to an in vitro cumulative release experiment.

[0096] 10 mg of microspheres and PBS buffer (pH 7.4) in Example 3 and Example 6 were placed in a 250 mL conical flask, and oscillated at a constant temperature of 37° C. on a water bath shaker. According to the sampling time, 1 mL of the solution was taken from the conical flask and the same amount of PBS buffer was added. The collected solution was filtered through a 0.45 μm injection filter, and 10 μL of the above solution was detected using HPLC. The in vitro cumulative release data of the sustained-release microspheres containing memantine prepared in Example 3 and Example 6 are shown in Table 1, and the release curves are shown in Table 1. Figure 8 shown.

[0097] Table 1 In vitro cumulative release data of memantine-containing sustained-release microspheres prepared in Example 3 and Example 6

[0098]

[0099]

[0100] Through Table 1 and Figure 8It can be seen that the sustained-release microspheres containing memantine in Example 3 have been released at 0.5 hours, and the release amount increased logarithmically from 0 to 24 hours, and the in vitro release gradually reached stability after 24 hours, and the release degree was maintained at more than 80%. The sustained-release microspheres containing memantine in Example 6 have been released at 0.5 hours, and the release amount increased logarithmically from 0 to 48 hours, and the in vitro release gradually reached stability after 72 hours, and the release degree was maintained at more than 80%. Comparing Example 3 and Example 6, it can be seen that the increase in the particle size of the microspheres effectively reduces the initial release of the drug and prolongs the release period. Since the raw material in Example 3 is liquid, with the collapse of the PLGA material, memantine is released relatively quickly from the microspheres.

[0101] Example 8: Pharmacokinetics in Animals

[0102] In this embodiment, the sustained-release microspheres containing memantine or its salt derivatives prepared in the above-mentioned embodiments 3, 4 and 6 are used as examples to carry out pharmacodynamic experiments. The comparative example is commercially available memantine hydrochloride tablets (Rottendorf Pharma GmbH 10 mg / tablet, 28 tablets / box). The memantine hydrochloride tablets are crushed and then prepared into a suspension of corresponding concentration.

[0103] Specific methods:

[0104] SD rats were used as model rats, with a body weight of 180 to 220 g. The sustained-release microspheres containing memantine or its salt derivatives prepared in Examples 3, 4 and 6 of the present invention were uniformly dispersed in physiological saline and injected subcutaneously at a dose of 15 mg / kg of memantine, with only one injection within 30 days. Commercially available oral tablets were administered to SD rats by gavage at a dose of 0.5 mg / kg / day of memantine for 30 consecutive days. Blood samples were collected at preset intervals, and the concentration of memantine in the blood was detected. The pharmacokinetic data of rats are shown in Table 2, and the pharmacokinetic curves are shown in Table 2. Fig. 9 shown.

[0105] Table 2 Blood drug concentration data of rats after injection of sustained-release microspheres containing memantine prepared in Example 3 and Example 6

[0106]

[0107]

[0108] From Table 2 and Fig. 9It can be seen that when injected only once within 30 days, Examples 3, 4 and 6 all have obvious sustained-release effects, and the drug is continuously released from the microspheres, indicating that the three microsphere preparations of memantine and its salts have obvious sustained-release properties, and memantine can still be detected in the plasma for at least more than 10 days. Compared with the existing commercially available oral tablets, the microsphere preparations of memantine and its salts of the present invention can effectively reduce the number of administrations while ensuring a better sustained-release effect. Among them, the raw material drug of Example 3 is liquid memantine. From Table 2 and Fig. 9 It can be seen that the drug release cycle is slightly short. As the PLGA material degrades, liquid memantine is released from the microspheres relatively quickly, and the release effect is not ideal. The sustained-release cycle of solid memantine and its salt microspheres is slightly longer. Memantine can still be detected in plasma for more than 20 days, but the blood drug concentration is lower than that of oral preparations after more than 10 days.

[0109] In summary, the present invention can fill the gap of memantine sustained-release microspheres at home and abroad by preparing a sustained-release microsphere containing memantine or its salt derivatives. In addition, it can be seen from the above-mentioned in vitro cumulative release experiment and the single-dose pharmacokinetic test of SD rats that the sustained-release microspheres have a certain sustained-release effect in vivo, which can reduce the gastrointestinal side effects often encountered in traditional oral medications and improve the compliance of patients with Alzheimer's disease to maximize the therapeutic effect, thereby meeting the needs of the market. The patient's compliance can be increased by injecting sustained-release microspheres containing memantine or its salt derivatives, eliminating the inconvenience of daily oral administration. In addition, the sustained-release microspheres of the present invention have a simple preparation method and can be prepared in large quantities in a short time. In addition, in the preparation process, except for adding surfactants, osmotic pressure regulators, biocompatible polymers, and pH regulators, no other excipients are added, the operation is simple, the cost is low, and the decomposition products have no toxic side effects in vivo, the safety performance is high, and the side effects are small.

[0110] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing sustained-release microspheres containing memantine or its salt derivatives, characterized in that: The preparation method comprises: Prepare an external water phase W2, dissolve a surfactant and an osmotic pressure regulator in ultrapure water, and adjust the pH to a target pH using a pH regulator; preparing an oil phase O, dissolving memantine or its salt derivative and a biocompatible polymer in an organic solvent, and vortexing to dissolve them; After mixing the external water phase W2 with the oil phase O, the mixture was added into a rapid membrane emulsifier to prepare an emulsion; The emulsion is stirred, solidified, washed and freeze-dried to obtain sustained-release microspheres containing memantine or its salt derivatives.

2. The method for preparing sustained-release microspheres containing memantine or its salt derivatives according to claim 1, characterized in that: The salt derivative containing memantine includes at least one or a combination of hydrochloride, pamoate, p-toluenesulfonate, benzoate or fumarate.

3. The method for preparing sustained-release microspheres containing memantine or its salt derivatives according to claim 2, characterized in that: When the memantine salt derivative is a hydrochloride, the preparation method comprises: Anhydrous ethanol and ultrapure water were used to prepare the internal aqueous phase W1; The biocompatible polymer is dissolved in an organic solvent and vortexed to dissolve it to prepare an oil phase O; Dissolve a surfactant and an osmotic pressure regulator in ultrapure water, and adjust the pH to a target pH using a pH regulator to prepare an external aqueous phase W2; Dissolve the memantine hydrochloride in the internal water phase W1, The inner water phase W1 is added to the oil phase O to disperse and form colostrum; the colostrum is added to the outer water phase W2 to disperse and form a pre-emulsion, and then added to a rapid membrane emulsifier to prepare an emulsion; The emulsion is stirred, solidified, washed and freeze-dried to obtain sustained-release microspheres containing memantine or its salt derivatives.

4. The method for preparing sustained-release microspheres containing memantine or its salt derivatives according to claim 1 or 3, characterized in that: The method for obtaining sustained-release microspheres containing memantine or its salt derivatives after stirring, solidifying, washing and freeze-drying the emulsion comprises: The emulsion is rapidly solidified into balls by evaporating the solvent; The sustained-release microspheres are obtained by washing the microspheres with an aqueous solution or an aqueous solution with an osmotic pressure regulator added thereto and drying them.

5. The method for preparing sustained-release microspheres containing memantine or its salt derivatives according to claim 1 or 3, characterized in that: The surfactant is at least one of PVA, Tween, SDS, SDBS and OP-10.

6. The method for preparing sustained-release microspheres containing memantine or its salt derivatives according to claim 1 or 3, characterized in that: The osmotic pressure regulator is sodium chloride or potassium chloride; the pH regulator is sodium hydroxide or sodium bicarbonate.

7. The method for preparing sustained-release microspheres containing memantine or its salt derivatives according to claim 1 or 3, characterized in that: The biocompatible polymer is at least one of PLGA, PELA, PLA, PHA, and PCL.

8. The method for preparing sustained-release microspheres containing memantine or its salt derivatives according to claim 1 or 3, characterized in that: The organic solvent is one of chloroform, dichloromethane, ethyl acetate, acetone, acetonitrile, anhydrous ethanol, anhydrous methanol or any combination thereof.

9. A sustained-release microsphere containing memantine or its salt derivatives, characterized in that: The sustained-release microspheres containing memantine or its salt derivatives are prepared by the preparation method of sustained-release microspheres containing memantine or its salt derivatives according to any one of claims 1 to 8.

10. The sustained-release microspheres containing memantine or its salt derivatives according to claim 9, characterized in that: The sustained-release microspheres containing memantine or its salt derivatives have a particle size of 10 to 30 μm and a drug loading of 1.5% to 20%.

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