Nimustine sustained-release implant as well as preparation method and application thereof

Abstract

The invention discloses a nimustine sustained-release implant as well as a preparation method and application thereof. The preparation method comprises the following steps: respectively micronizing 5-60 parts by mass of nimustine and 40-95 parts by mass of biodegradable lactide-glycolide copolymer (PLGA), mixing and pretreating the nimustine and the PLGA, then adding the nimustine and the PLGA into a feeder of a hot melt extruder, and conveying materials to the hot melt extruder by a screw rod according to a set rotating speed for extrusion; and enabling the obtained extruded material to pass through a crawler belt to obtain a rod and wire material, and cutting, granulating, sterilizing and sub-packaging the rod and wire material to obtain a finished product of the slow-release implant. The preparation method disclosed by the invention is environment-friendly and efficient, the obtained sustained-release implant can be continuously and slowly released in local tissue fluid of a human body, the drug concentration in the tissue fluid is high, the local treatment intensity formed by one-time administration is dozens to hundreds of times of intravenous chemotherapy or oral treatment, the adverse reaction is few, the bioavailability of the drug is greatly improved, and the preparation method is suitable for industrial production. Pains of patients are relieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of pharmaceutical preparation, and particularly relates to a nimustine sustained-release implant and a preparation method and application thereof. BACKGROUND

[0002] Although conventional chemotherapy as one of the five pillars of cancer treatment plays a pivotal role in the field of cancer treatment, its problems, especially the daunting side effects and uncertain efficacy caused by the long-neglected unreasonable treatment concept, have become the pain points of limiting the application of conventional chemotherapy for cancer, seriously affecting the clinical promotion and market development of chemotherapy drugs.

[0003] With the rapid development of sustained-release technology, local implantation of chemotherapy drugs and their good clinical effects provide a new way to solve the pain points of conventional chemotherapy drugs. For example, in the treatment of brain glioma, GLIADEL® WAFER approved for marketing by FDA in 1996 is locally administered to solve the problems of effective drug concentration and maintenance time in conventional chemotherapy. However, since the marketing of Gliadel implant tablets, although they have certain advantages compared with intravenous administration, the overall efficacy is not satisfactory, which is mainly attributed to the release characteristics of the sustained-release carrier used in Gliadel implant tablets, i.e., polyphenylpropane (p-carboxyphenylpropane (p-CPP): sebacic acid (SA) copolymer, 80:20), which has many defects, such as but not limited to: unstable sustained-release system, unstable release, obvious burst release, poor efficacy, and large side effects, which limit the clinical application of the product. Shandong Lanjin Biotechnology Co., Ltd. used PLGA as a carrier material to prepare Casant implant (CN104523566A), which made up for the defects of unstable release and obvious burst release in Gliadel implant tablets, but the preparation process also has defects that cannot be ignored, such as but not limited to: first, the solvent method is used, the preparation process is too long, the process is complicated, and it is difficult to mass-produce; second, the low-temperature control requirement is high in the production process, and the batch difference is large; third, organic solvents such as dichloromethane are used, which easily cause environmental and residual problems. Therefore, the Casant implant cannot be further promoted in the clinic.

[0004] Ideally, sustained-release implants should exhibit stable release, good efficacy, low toxicity, and a relatively simple manufacturing process that facilitates mass production without generating waste gas or liquid. Therefore, our research team employed hot melt extrusion (HME) to prepare nimustine sustained-release implants. While Chengdu Kanghong Pharmaceutical Group Co., Ltd. has published a hot melt extrusion process for preparing axitinib intraocular implant (CN114533648A), this process involves simple material mixing followed by extrusion. The extrusion process involves a wide and relatively high temperature range, which can significantly impact heat-sensitive APIs. Furthermore, it lacks in-depth research on pretreatment, temperature parameters during extrusion, and post-extrusion product molding parameters, and provides corresponding examples. Therefore, We thoroughly explored and optimized the process parameters related to each stage of hot melt extrusion, especially the pretreatment process before preparation and the various stages of extrusion. Nimustine was selected as the active pharmaceutical ingredient (due to its superior melting point compared to carmustine: 30℃ for carmustine and 125℃ for nimustine), and PLGA was used as the excipient to prepare a nimustine sustained-release implant. This significantly shortened the implant preparation time, and the entire process did not use organic solvents, thus protecting the environment. More importantly, it boasts a high degree of automation, a relatively simple process, and is easy to mass-produce industrially. Furthermore, the prepared nimustine sustained-release implant was validated in in vitro release experiments, demonstrating good therapeutic effects in animal studies of solid tumors such as lung cancer, breast cancer, colon cancer, esophageal cancer, gastric cancer, and pancreatic cancer. Summary of the Invention

[0005] To overcome the shortcomings and deficiencies of the prior art, the primary purpose of this invention is to provide a nimustine sustained-release implant, its preparation method, and its application.

[0006] The present invention is achieved as follows: a nimustine sustained-release implant, wherein the sustained-release implant contains 5-60 parts by weight of nimustine and 40-95 parts by weight of a matrix material, wherein the matrix material is a biodegradable lactide-glycolic acid copolymer (PLGA).

[0007] Preferably, the mass ratio of nimosine to skeleton material is 1:1 to 4.

[0008] Preferably, the weight-average molecular weight of the lactide-glycolic acid copolymer is 10,000 to 50,000 Da, wherein the molar ratio of lactide to glycolide is 50:50 to 90:10.

[0009] Preferably, the molar ratio of lactide to glycolide is 50:50, and the weight-average molecular weight is 20,000 to 30,000 Da.

[0010] This invention further discloses a method for preparing the above-mentioned sustained-release implant, the method comprising the following steps: (1) The nimosine and the skeleton material are respectively subjected to micronization treatment.

[0011] (2) After mixing and pretreating the nimosine and skeleton material described in (1), the mixture is added to the feeder of the hot melt extruder, and the screw conveys the material to the hot melt extruder for extrusion at the set speed. (3) The extruded material obtained in step (2) is passed through a conveyor belt to obtain bar wire material. The bar wire material is cut, granulated, sterilized, and packaged to obtain the sustained-release implant product.

[0012] Preferably, in step (1), the particle size D90 of the nimustine micro powder is less than 20 μm; and the particle size D90 of the skeleton material component micro powder is less than 100 μm.

[0013] Preferably, in step (2), the mixing pretreatment is selected from 2 to 8°C, the precooling temperature is -80°C, and the time is 12 to 24 hours.

[0014] Preferably, in step (3), the extruder conveying section is 40-100°C, the preheating section is 80-120°C, the mixing section is 80-120°C, and the forming section is 40-100°C.

[0015] The present invention further discloses the use of the above-mentioned sustained-release implant in the preparation of cancer treatment drugs for humans or animals.

[0016] Preferably, the cancer is selected from glioma, breast cancer, lung cancer, colon cancer, esophageal cancer, gastric cancer, pancreatic cancer, lymphoma, and metastatic tumors.

[0017] Comparative studies have shown that this preparation method is superior to existing organic solvent methods, and it has the following beneficial effects: (1) The hot melt extrusion process of this invention is a continuous production process with process control. Compared with the solvent method of Blue Gold Bio, it greatly shortens the preparation time of nimustine sustained-release implants. At the same time, it conforms to the development direction of modern industrial technology and is conducive to the intelligent upgrading of formulation processes. It has a high degree of automation, can realize batch production, and has small batch-to-batch differences. (2) Environmental protection: The entire production process of the slow-release implant of this invention produces no waste gas or waste liquid, which is in line with the concept of environmental protection; (3) In this invention, the active ingredient is dispersed in the polymer skeleton material through blending with the active ingredient. The polymer skeleton material plays a role in protecting the active ingredient by physical encapsulation, which slows down the degradation of the active ingredient in vivo and plays a role in sustained release. (4) High local concentration: The sustained-release implant of the present invention can be continuously and slowly released in the local tissue fluid of the human body. The drug concentration in the tissue fluid is high. The therapeutic intensity formed by a single administration is equivalent to tens to hundreds of times that of intravenous chemotherapy or oral treatment. Moreover, there are few adverse reactions, which greatly improves the bioavailability of the drug and reduces the patient's pain.

[0018] (5) Long duration of action on tumors: The sustained-release implant of the present invention continues to release in the body for several weeks or months, which increases the stability of drug treatment and prolongs the duration of drug action.

[0019] (6) Good biocompatibility and low toxicity: The sustained-release implant of the present invention can be made of biodegradable materials, which can be degraded and absorbed by the human body, avoiding the risk of removal by surgery again.

[0020] (7) Timely administration: Locally targeted sustained-release agents overcome the defects of conventional chemotherapy drugs, fill the gap of no chemotherapy drugs available during the "recovery period" of 2 to 4 weeks after surgery, and can effectively control the growth and spread of residual active tumor cells after surgery.

[0021] (8) Good stability: The sustained-release implant of the present invention can preserve and stabilize the activity of sensitive active pharmaceutical ingredients.

[0022] (9) Good targeting: The sustained-release implant of the present invention has good targeting and can achieve local positioning. It is not limited by natural barriers such as the blood-brain barrier, hematoma barrier, and dense extracellular matrix, or by the high intratumoral fluid pressure, which can ensure the concentration and duration of chemotherapy drugs at the tumor site. While improving the local treatment effect, it can also reduce the side effects caused by systemic absorption and reduce the development of drug resistance. Attached Figure Description

[0023] Figure 1 It is a nimustine implant (PLGA process study with different proportions). Figure 2 It is a nimustine implant (PLGA50:50 study of different molecular weights); Figure 3 This is an evaluation of the homogeneity of nimustine implants (PLGA50:50). Figure 4 This study investigated the in vitro release of nimustine implants with different drug loadings. Figure 5 This is a study on the in vivo release of nimustine implants; Figure 6 Inhibitory effect of intratumoral implantation of nimustine extended-release implant on the growth of human breast cancer (MDAMB231) in nude mice; Figure 7 The growth inhibition rate of intratumorally implanted nimustine extended-release implant on human breast cancer (MDAMB231) in nude mice; Figure 8 The study investigated the growth-inhibiting effect of intratumoral implantation of nimustine extended-release implant on human lung cancer (Lewis) in nude mice. Figure 9 The growth inhibition rate of intratumorally implanted nimustine extended-release implant on human lung cancer (Lewis) in nude mice; Figure 10 The study investigated the growth-inhibiting effect of intratumoral implantation of nimustine extended-release implant on human colon cancer (HCT-8) in nude mice. Figure 11 The growth inhibition rate of intratumorally implanted nimustine extended-release implant on human colon cancer (HCT-8) in nude mice; Figure 12 The growth-inhibiting effect of intratumoral implantation of nimustine sustained-release implant on human esophageal cancer (9706) in nude mice; Figure 13 The growth inhibition rate of nimustine extended-release implanted intratumorally in nude mice with human esophageal cancer (9706); Figure 14 The study investigated the growth-inhibiting effect of intratumoral implantation of nimustine sustained-release implant on human gastric cancer (BJC803) in nude mice. Figure 15 The growth inhibition rate of intratumorally implanted nimustine extended-release implant on human gastric cancer (BJC803) in nude mice; Figure 16 The study investigated the growth-inhibiting effect of intratumoral implantation of nimustine sustained-release implant on human pancreatic cancer (PANC-1) in nude mice. Figure 17 It is the growth inhibition rate of intratumorally implanted nimustine extended-release implant on human pancreatic cancer (PANC-1) in nude mice. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] Example 1: (1) 4g of nimustine and 16g of lactide-glycolic acid copolymer PLGA (weight average molecular weight of 10000~50000 Da, molar ratio of lactide to glycolide of 50:50, 90:10, 75:25) were respectively micronized (nimustine particle size D90 is 19μm, PLGA particle size D90 is 90μm); the formulation of nimustine implant components with different PLGA ratios is shown in Table 1 below.

[0026] Table 1. Formulations of Nimustine Implant Components with Different PLGA Ratios

[0027] (2) Nimustine and lactide-glycolic acid copolymer PLGA were mixed evenly at 8°C for 60 min and pre-cooled at -80°C for 12 h to obtain the feed material; (3) Place the feed into the mixer and mix for 1 hour. Then transfer it to the feeder of the hot melt extruder, start the feeder, take the extruder rod when the torque is stable, and the screw conveys the material to the hot melt extruder at the set speed. The extruder conveying section is 40°C, the preheating section is 80°C, the mixing section is 80°C, and the forming section is 40°C. (4) The extruded material obtained in step (3) is passed through a conveyor belt to obtain bar and wire material. The conveyor belt speed is 40 rpm. The bar and wire material is cut and granulated. The cutting speed is 200 granules / min to obtain a sustained-release implant intermediate with a diameter of 1 mm and a length of 10 mm. The obtained intermediate is sterilized by irradiation (irradiation dose is 15 KGy to 50 KGy). The packaging material is aluminum-plastic composite film or vial (10 ml) to obtain the sustained-release implant finished product.

[0028] In this embodiment of the invention, the time from feeding to packaging and cutting does not exceed 2 hours.

[0029] The nimustine sustained-release implant prepared in Example 1 was used for in vitro release assay. A shaker method was employed, using purified water as the release medium at a shaker speed of 50 rpm. Sampling times were 1, 7, 14, 21, 28, and 35 days. 5 ml of the solution was collected at each time, and a blank release medium of the same volume and temperature was added simultaneously. All samples were filtered through a 0.45 μm filter and measured using a UV-Vis spectrophotometer. The cumulative release was calculated, and the results are as follows: Figure 1 As shown in Table 1, under the same drug loading (as shown in Table 1), implant 002 (PLGA90:10) and implant 003 (PLGA75:25) both exhibited excessive surface release on the first day compared to implant 001 (PLGA50:50), and the overall release was relatively unstable. Figure 2 This further demonstrates the stability of the PLGA50:50 drug delivery system formulation.

[0030] Example 2: (1) 4 grams of nimustine and 16 grams of lactide-glycolic acid copolymer PLGA (weight average molecular weights of 10,000~19,000 Da, 20,000~29,000 Da, 30,000~39,000 Da, and 40,000~50,000 Da, respectively, with a molar ratio of lactide to glycolide of 50:50) were micronized (nimustine particle size D90 was 19 μm, and PLGA particle size D90 was 90 μm). The formulation of nimustine implant components with different molecular weights of PLGA50:50 is shown in Table 2 below.

[0031] Table 2. Formulation of Nimustine Implant Components with Different Molecular Weights in PLGA50:50

[0032] (2) Nimustine and lactide-glycolic acid copolymer PLGA were mixed evenly at 0℃ for 10 min and pre-cooled at -80℃ for 12 h to obtain the feed material; (3) Place the feed into the mixer and mix for 1 hour. Then transfer it to the feeder of the hot melt extruder. Start the feeder and take the extruder rod when the torque is stable. The screw conveys the material to the hot melt extruder at the set speed. The extruder conveying section is 100°C, the preheating section is 120°C, the mixing section is 120°C, and the forming section is 100°C. (4) The extruded material obtained in step (3) is passed through a conveyor belt to obtain bar and wire material. The conveyor belt speed is 40 rpm. The bar and wire material is cut and granulated. The cutting speed is 200 granules / min to obtain a sustained-release implant intermediate with a diameter of 1 mm and a length of 10 mm. The obtained intermediate is sterilized by irradiation (irradiation dose is 15 KGy to 50 KGy). The packaging material is aluminum-plastic composite film or vial (10 ml) to obtain the sustained-release implant finished product.

[0033] In this embodiment of the invention, the time from feeding to packaging and cutting does not exceed 2 hours.

[0034] Six parallel samples of the nimustine sustained-release implant prepared in Example 2 were subjected to in vitro release assays using a shaker method with purified water as the release medium at a speed of 50 rpm. Sampling times were 1, 7, 14, 21, 28, and 35 days. 5 ml of the solution was collected, and an equal volume of blank release medium at the same temperature was added simultaneously. All samples were filtered through a 0.45 μm filter and measured using a UV-Vis spectrophotometer. The cumulative release was calculated, and the results are as follows: Figure 3 As shown, 005 (10000~19000Da) indicates excessively rapid release, while 006 (30000~39000Da) and 007 (40000~50000Da) indicate adverse conditions, all of which are unfavorable for the release of nimustine.

[0035] Example 3: (1) Nimustine and lactide-glycolic acid copolymer PLGA (weight average molecular weight of 20,000~29,000 Da, molar ratio of lactide to glycolide of 50:50) of different masses were micronized (nimustine particle size D90 of 19 μm, PLGA particle size D90 of 90 μm); wherein, the mass ratio of nimustine to PLGA was 5:95, 10:90, 20:80, 30:70, 40:60, respectively; the formulation of nimustine implant components with different drug loading is shown in Table 3 below.

[0036] Table 3. Prescriptions for Nimustine Extended-Release Implants with Different Drug Loading Capacities

[0037] (2) Nimustine and lactide-glycolic acid copolymer PLGA were mixed evenly at 2℃ for 20 min and pre-cooled at -80℃ for 12 h to obtain the feed material; (3) Place the feed into the mixer and mix for 1 hour. Then transfer it to the feeder of the hot melt extruder, start the feeder, take the extruder rod when the torque is stable, and the screw conveys the material to the hot melt extruder at the set speed. The extruder conveying section is 50°C, the preheating section is 100°C, the mixing section is 100°C, and the forming section is 80°C. (4) The extruded material obtained in step (3) is fed through a conveyor belt to obtain bar and wire material. The conveyor belt speed is 40 rpm. The bar and wire material is cut and granulated at a cutting speed of 200 pellets / min to obtain a sustained-release implant intermediate with a diameter of 1 mm and a length of 10 mm. The obtained intermediate is sterilized by irradiation (irradiation dose is 15 KGy to 50 KGy). The packaging material is aluminum-plastic composite film or vial (10 ml) to obtain the finished sustained-release implant, as shown in Table 3.

[0038] Six parallel samples of the nimustine sustained-release implant prepared in Example 3 were subjected to in vitro release assays using a shaker method with purified water as the release medium at a speed of 50 rpm. Sampling times were 1, 7, 14, 21, 28, and 35 days. 5 ml of the solution was collected, and an equal volume of blank release medium at the same temperature was added simultaneously. The samples were filtered through a 0.45 μm filter and measured using a UV-Vis spectrophotometer. The cumulative release was calculated, and the results are as follows: Figure 4 As shown, compared to batch 015, batches 013 and 014 released less, while batch 017 released more, both of which are not conducive to tumor treatment. Batch 015 and 016 released moderate amounts, which is initially feasible. Further verification will be conducted based on animal experiments later.

[0039] Example 4: (1) 5g of nimustine and 95g of lactide-glycolic acid copolymer PLGA (weight average molecular weight of 20000~29000Da, molar ratio of lactide to glycolide of 50:50) were micronized (nimustine particle size D90 is 19μm, PLGA particle size D90 is 90μm).

[0040] (2) Nimustine and lactide-glycolic acid copolymer PLGA were mixed evenly at 4°C for 30 min and pre-cooled at -80°C for 10 h to obtain the feed material; (3) Place the feed into the mixer and mix for 1 hour. Then transfer it to the feeder of the hot melt extruder, start the feeder, take the extruder rod when the torque is stable, and the screw conveys the material to the hot melt extruder at the set speed. The extruder conveying section is 90°C, the preheating section is 90°C, the mixing section is 90°C, and the forming section is 90°C. (4) The extruded material obtained in step (3) is passed through a conveyor belt to obtain bar and wire material. The conveyor belt speed is 30 rpm. The bar and wire material is cut and granulated. The cutting speed is 200 granules / min to obtain a sustained-release implant intermediate with a diameter of 1 mm and a length of 10 mm. The obtained intermediate is sterilized by irradiation (irradiation dose is 15 KGy ~ 50 KGy). The packaging material is aluminum-plastic composite film or vial (10 ml) to obtain the sustained-release implant finished product.

[0041] Example 5: (1) 60g of nimustine and 40g of lactide-glycolic acid copolymer PLGA (weight average molecular weight of 20000~29000Da, molar ratio of lactide to glycolide of 50:50) were micronized (nimustine particle size D90 is 19μm, PLGA particle size D90 is 90μm).

[0042] (2) Nimustine and lactide-glycolic acid copolymer PLGA were mixed evenly at 4°C for 30 min and pre-cooled at -80°C for 10 h to obtain the feed material; (3) Place the feed into the mixer and mix for 1 hour. Then transfer it to the feeder of the hot melt extruder, start the feeder, take the extruder rod when the torque is stable, and the screw conveys the material to the hot melt extruder at the set speed. The extruder conveying section is 60°C, the preheating section is 70°C, the mixing section is 110°C, and the forming section is 60°C. (4) The extruded material obtained in step (3) is passed through a conveyor belt to obtain bar and wire material. The conveyor belt speed is 50 rpm. The bar and wire material is cut and granulated. The cutting speed is 200 pellets / min to obtain a sustained-release implant intermediate with a diameter of 1 mm and a length of 10 mm. The obtained intermediate is sterilized by irradiation (irradiation dose is 15 KGy to 50 KGy). The packaging material is aluminum-plastic composite film or vial (10 ml) to obtain the sustained-release implant finished product.

[0043] Application Example: The following experimental procedures were performed using the nimustine sustained-release implant prepared in Example 3.

[0044] I. In vivo release study Experimental Methods: Thirty New Zealand white rabbits were divided into two large groups, each of which was further divided into five small groups of three rabbits each. Nimustine extended-release implants (batch 015 and 016) irradiated with 30 kGy were placed intracranially. Animals were sacrificed at 3, 7, 14, 21, and 28 days post-administration. Residual drug particles were removed from the brain and stored at -20°C. The remaining amount of nimustine was determined using HPLC. Results are as follows: Figure 5 As shown, the in vivo release of batches 015 and 016 is stable and feasible.

[0045] II. Breast Cancer Suppression Research Experimental method: Female nude mice of the same sex and similar weight (18±2 g) were selected, and human breast cancer (MDAMB231) tumor cells were injected subcutaneously into each mouse (2×10⁻⁶ mcg per mouse). 5 (Number of tumor cells) were injected into the right hypochondrium of nude mice. When the tumor diameter grew to approximately 0.8 cm, the mice were randomly divided into 5 groups of 5 animals each: control group (no treatment), polymer group (without nimustine, referred to as polymer group), nimustine extended-release implant 5.0% group (batch 013), nimustine extended-release implant 10.0% group (batch 014), nimustine extended-release implant 20% group (batch 015), nimustine extended-release implant 30% group (batch 016), and nimustine extended-release implant 40% group (batch 017) (referred to as implant 5.0%, implant 10.0%, implant 20%, implant 30%, and implant 40%). The polymer group and nimustine extended-release implant were implanted into the tumor tissue 1 cm below the lower margin of the tumor using a puncture needle. The tumor volume measurement on the day of implantation was set as day 0, and the tumor diameter (in mm) was measured daily thereafter. 3 The tumor inhibition rate was calculated by weighing the animals every three days and euthanizing them by dislocation on the 35th day.

[0046] The results are as follows Figure 6 , 7 As shown, the results indicate that the tumor inhibition rate is significantly dose-dependent, with the tumor inhibition rates of 5%, 10%, 20%, and 30% of the implant being 57.5%, 64.1%, 79.6%, and 90.3%, respectively (P < 0.001, which is highly statistically significant).

[0047] III. Lung Cancer Suppression Research Experimental method: Female nude mice of the same sex and similar weight (18±2 g) were selected, and each mouse was subcutaneously injected with a Lewis lung cancer tumor strain (2×10⁻⁶ mcg). 5 (Number of tumor cells) were injected into the right hypochondrium of nude mice. When the tumor diameter grew to approximately 0.8 cm, the mice were randomly divided into 5 groups of 5 animals each: control group (no treatment), polymer group (without nimustine, referred to as polymer group), nimustine extended-release implant 5.0% group (batch 013), nimustine extended-release implant 10.0% group (batch 014), nimustine extended-release implant 20% group (batch 015), nimustine extended-release implant 30% group (batch 016), and nimustine extended-release implant 40% group (batch 017) (referred to as implant 5.0%, implant 10.0%, implant 20%, implant 30%, and implant 40%). The polymer group and nimustine extended-release implant were implanted into the tumor tissue 1 cm below the lower margin of the tumor using a puncture needle. The tumor volume measurement on the day of implantation was set as day 0, and the tumor diameter (in mm) was measured daily thereafter. 3The tumor inhibition rate was calculated by weighing the animals every three days and euthanizing them by dislocation on the 35th day.

[0048] The results are as follows Figure 8 , 9 As shown, the results indicated a significant dose-dependent relationship between tumor inhibition rate and drug dosage. The 30% implant significantly inhibited tumor growth, with an inhibition rate of 85.6% (P < 0.001, highly statistically significant). One animal died on day 7 of treatment with the 40% implant, while the remaining animals showed no significant weight change, preliminarily ruling out dose-related toxicity. By the end of the experiment, the tumors in this group had largely disappeared (not included in the statistical analysis). Conclusion: Nimustine extended-release implants have a dose-dependent effect, with significant differences between the 30% and 40% groups compared to the control group.

[0049] IV. Colon Cancer Suppression Research Experimental method: Female nude mice of the same sex and similar weight (18±2 g) were selected, and human colon cancer (HCT-8) tumor cells (2×10⁻⁶ mcg per mouse) were subcutaneously injected into each mouse. 5 (Number of tumor cells) were injected into the right hypochondrium of nude mice. When the tumor diameter grew to approximately 0.8 cm, the mice were randomly divided into 5 groups of 5 animals each: control group (no treatment), polymer group (without nimustine, referred to as polymer group), nimustine extended-release implant 5.0% group (batch 013), nimustine extended-release implant 10.0% group (batch 014), nimustine extended-release implant 20% group (batch 015), nimustine extended-release implant 30% group (batch 016), and nimustine extended-release implant 40% group (batch 017) (referred to as implant 5.0%, implant 10.0%, implant 20%, implant 30%, and implant 40%). The polymer group and nimustine extended-release implant were implanted into the tumor tissue 1 cm below the lower margin of the tumor using a puncture needle. The tumor volume measurement on the day of implantation was set as day 0, and the tumor diameter (in mm) was measured daily thereafter. 3 The tumor inhibition rate was calculated by weighing the animals every three days and euthanizing them by dislocation on the 35th day.

[0050] The results are as follows Figure 10 , 11 As shown, the results indicate that the tumor inhibition rate is significantly dose-dependent, with the tumor inhibition rates of 5%, 10%, 20%, and 30% of the implant being 34.5%, 45.7%, 54.3%, and 66.8%, respectively (P < 0.001, which is highly statistically significant). V. Research on Esophageal Cancer Inhibition Experimental method: Female nude mice of the same sex and similar weight (18±2 g) were selected and injected subcutaneously with human esophageal cancer (9706) (2×10⁻⁶ g per mouse). 5(Number of tumor cells) were injected into the right hypochondrium of nude mice. When the tumor diameter grew to approximately 0.8 cm, the mice were randomly divided into 5 groups of 5 animals each: control group (no treatment), polymer group (without nimustine, referred to as polymer group), nimustine extended-release implant 5.0% group (batch 013), nimustine extended-release implant 10.0% group (batch 014), nimustine extended-release implant 20% group (batch 015), nimustine extended-release implant 30% group (batch 016), and nimustine extended-release implant 40% group (batch 017) (referred to as implant 5.0%, implant 10.0%, implant 20%, implant 30%, and implant 40%). The polymer group and nimustine extended-release implant were implanted into the tumor tissue 1 cm below the lower margin of the tumor using a puncture needle. The tumor volume measurement on the day of implantation was set as day 0, and the tumor diameter (in mm) was measured daily thereafter. 3 The tumor inhibition rate was calculated by weighing the animals every three days and euthanizing them by dislocation on the 35th day.

[0051] The results are as follows Figure 12 , 13 As shown, the results indicate that the tumor inhibition rate is significantly dose-dependent, with the tumor inhibition rates of 5%, 10%, 20%, and 30% of the implant being 46.9%, 57.6%, 66.8%, and 87.6%, respectively (P < 0.001, indicating high statistical significance). VI. Research on Gastric Cancer Inhibition Experimental method: Female nude mice of the same sex and similar weight (18±2 g) were selected and injected subcutaneously with human gastric cancer (BJC803) (2×10⁻⁶ g / m²). 5 (Number of tumor cells) were injected into the right hypochondrium of nude mice. When the tumor diameter grew to approximately 0.8 cm, the mice were randomly divided into 5 groups of 5 animals each: control group (no treatment), polymer group (without nimustine, referred to as polymer group), nimustine extended-release implant 5.0% group (batch 013), nimustine extended-release implant 10.0% group (batch 014), nimustine extended-release implant 20% group (batch 015), nimustine extended-release implant 30% group (batch 016), and nimustine extended-release implant 40% group (batch 017) (referred to as implant 5.0%, implant 10.0%, implant 20%, implant 30%, and implant 40%). The polymer group and nimustine extended-release implant were implanted into the tumor tissue 1 cm below the lower margin of the tumor using a puncture needle. The tumor volume measurement on the day of implantation was set as day 0, and the tumor diameter (in mm) was measured daily thereafter. 3 The tumor inhibition rate was calculated by weighing the animals every three days and euthanizing them by dislocation on the 35th day.

[0052] The results are as follows Figure 14 , 15As shown, the results indicate that the tumor inhibition rate is significantly dose-dependent, with the tumor inhibition rates of 5%, 10%, 20%, and 30% of the implant being 44.7%, 56.1%, 72.5%, and 81.3%, respectively (P < 0.001, which is highly statistically significant).

[0053] VII. Research on Pancreatic Cancer Suppression Experimental method: Female nude mice of the same sex and similar weight (18±2 g) were selected and injected subcutaneously with human pancreatic cancer (PANC-1) (2×10⁻⁶ mcg per mouse). 5 (Number of tumor cells) were injected into the right hypochondrium of nude mice. When the tumor diameter grew to approximately 0.8 cm, the mice were randomly divided into 5 groups of 5 animals each: control group (no treatment), polymer group (without nimustine, referred to as polymer group), nimustine extended-release implant 5.0% group (batch 013), nimustine extended-release implant 10.0% group (batch 014), nimustine extended-release implant 20% group (batch 015), nimustine extended-release implant 30% group (batch 016), and nimustine extended-release implant 40% group (batch 017) (referred to as implant 5.0%, implant 10.0%, implant 20%, implant 30%, and implant 40%). The polymer group and nimustine extended-release implant were implanted into the tumor tissue 1 cm below the lower margin of the tumor using a puncture needle. The tumor volume measurement on the day of implantation was set as day 0, and the tumor diameter (in mm) was measured daily thereafter. 3 The tumor inhibition rate was calculated by weighing the animals every three days and euthanizing them by dislocation on the 35th day.

[0054] The results are as follows Figure 16 , 17 As shown, the results indicate that the tumor inhibition rate is significantly dose-dependent, with the tumor inhibition rates of 5%, 10%, 20%, and 30% of the implant being 38.6%, 56.5%, 73.1%, and 83.9%, respectively (P < 0.001, which is highly statistically significant).

[0055] In the above embodiments, the tumor growth curve is calculated as follows: the diameter of each group of tumors is measured periodically using a vernier caliper, and the tumor volume is calculated using the formula V = (A×B2) / 2, where A is the major axis and B is the minor axis.

[0056] The tumor inhibition rate is calculated as follows: TGI% = (TVC - TVT) / TVC × 100%, where TVC is the average tumor volume of the control group and TVT is the average tumor volume of the treatment group.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A nimustine sustained-release implant, characterized in that, The sustained-release implant contains 5-60 parts by weight of nimustine and 40-95 parts by weight of matrix material, wherein the matrix material is a biodegradable lactide-glycolic acid copolymer (PLGA).

2. The sustained-release implant as described in claim 1, characterized in that, The mass ratio of nimosine to the skeleton material is 1:1 to 4.

3. The sustained-release implant as described in claim 1, characterized in that, The weight-average molecular weight of the lactide-glycolic acid copolymer is 10,000 to 50,000 Da, wherein the molar ratio of lactide to glycolide is 50:50 to 90:

10.

4. The sustained-release implant as described in claim 3, characterized in that, The molar ratio of lactide to glycolide is 50:50, and the weight-average molecular weight is 20,000 to 30,000 Da.

5. A method for preparing the sustained-release implant according to any one of claims 1 to 4, characterized in that, The method includes the following steps: (1) The nimosine and the skeleton material are respectively subjected to micronization treatment; (2) After mixing and pretreating the nimosine and skeleton material described in (1), the mixture is added to the feeder of the hot melt extruder, and the screw conveys the material to the hot melt extruder for extrusion at the set speed. (3) The extruded material obtained in step (2) is passed through a conveyor belt to obtain bar wire material. The bar wire material is cut, granulated, sterilized, and packaged to obtain the sustained-release implant product.

6. The method as described in claim 5, characterized in that, In step (1), the particle size D90 of the nimustine micro powder is less than 20 μm; the particle size D90 of the skeleton material component micro powder is less than 100 μm.

7. The method as described in claim 5, characterized in that, In step (2), the mixing pretreatment is selected from 2 to 8°C, the precooling temperature is -80°C, and the time is 12 to 24 hours.

8. The method as described in claim 5, characterized in that, In step (3), the extruder conveying section is 40-100°C, the preheating section is 80-120°C, the mixing section is 80-120°C, and the forming section is 40-100°C.

9. The use of the sustained-release implant according to claims 1 to 4 in the preparation of cancer treatment drugs for humans or animals.

10. The application as described in claim 9, characterized in that, The cancers mentioned are selected from glioma, breast cancer, lung cancer, colon cancer, esophageal cancer, stomach cancer, pancreatic cancer, lymphoma, and metastatic tumors.

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