Meloxicam sustained-release injection, preparation method thereof, and medicine for arthritis analgesia

Abstract

The invention discloses a meloxicam sustained-release injection, a preparation method thereof and a medicine for arthritis analgesia. The injection contains an injectable solvent, a biodegradable sustained-release material, a release regulator and a medicine. After injection, an in-situ reservoir is formed through phase conversion, the solvent diffuses from the reservoir to the injection site, the medicine is wrapped in the reservoir by the sustained-release material and slowly released to achieve a sustained-release effect, provide a long-term therapeutic effect, reduce the number of medications, reduce the fluctuation of blood drug concentration, and improve patient compliance. The injection has simple components, is easy to prepare, has low cost, and takes a short time, and is suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of pharmaceutical preparations, and in particular relates to a meloxicam sustained-release injection and a preparation method thereof, and a medicine for arthritis analgesia. Background Art

[0002] Arthritis is a common chronic disease, the most common of which are osteoarthritis (OA) and rheumatoid arthritis (RA). Osteoarthritis (OA) is a non-inflammatory degenerative joint disease characterized by joint pain and stiffness. Currently, most commonly used drugs are non-steroidal anti-inflammatory drugs, such as meloxicam, acetaminophen, etc., which are used for anti-inflammatory and analgesic purposes to relieve symptoms. Rheumatoid arthritis (RA) is an autoimmune disease with multi-system inflammation mainly involving peripheral joints. It is mainly manifested as chronic, synovial arthritis and extra-articular lesions. The teratogenicity rate of patients in the long term is extremely high, which seriously reduces the quality of life.

[0003] The chemical name of meloxicam is 4-hydroxy-2-methyl-N-(5-methyl-2-thiazolyl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide, and its molecular formula is C 14 H 13 N3O4S2, molecular weight 351.40, structural formula as shown in formula (I):

[0004]

[0005] It is an enol nonsteroidal anti-inflammatory drug, a highly selective COX-2 inhibitor, with weak inhibition on COX-1. It has antipyretic, anti-inflammatory and analgesic effects, little irritation to the stomach and local tissues, and few adverse reactions. It is widely used in the treatment of osteoarthritis, rheumatoid arthritis, ankylosing spondylitis and other muscle or bone pain (such as low back pain, etc.), and can also be used to relieve mild to moderate pain in patients after surgery.

[0006] Since meloxicam is poorly water-soluble, its Tmax after oral administration is 5-6 hours, and its onset of action is slow. Compared with oral preparations, meloxicam injection can take effect quickly after intramuscular injection, but it is metabolized quickly in the body. When treating painful osteoarthritis, rheumatoid arthritis, and ankylosing spondylitis, it needs to be injected intramuscularly once a day to achieve an analgesic effect. In addition, in order to increase the solubility of meloxicam in the solution, meloxicam injection contains excipients such as meglumine, but the safety of this excipient is poor, and adverse reactions such as angioedema, itching, and rash are prone to occur at the injection site after injection. The FDA has also approved an intravenous suspension For postoperative analgesia, It is a meloxicam nanocrystal suspension, which is administered by intravenous (IV) injection, which can make meloxicam take effect quickly. It needs to be administered once a day and has been withdrawn from the market. At present, in the acute attack period of painful osteoarthritis, rheumatoid arthritis, and ankylosing spondylitis, meloxicam injection needs to be injected intramuscularly every day in the first few days of treatment. On the one hand, local injection has poor safety; on the other hand, it needs to be injected daily, and patients have poor compliance with medication.

[0007] At present, meloxicam injection is also prepared by formulation methods at home and abroad to solve the problem of drug safety or achieve the purpose of sustained release. However, most studies focus on solving the safety of injection drugs. The preparations studied have no sustained release effect and still need to be taken once a day. Only a few studies have prepared meloxicam sustained-release injections, but the preparation process is complicated and not easy to industrialize, and the sustained-release effect is not ideal.

[0008] For example, Chinese patent CN115844820 A describes a meloxicam suspension injection and its preparation method. Through the precipitation-high pressure homogenization method, the particle size of the API is controlled to be less than 200nm, and the suspension injection is prepared. The preparation is administered by intravenous injection, and the preparation can maintain an effective blood drug concentration for 21.3h. In the preparation, meloxicam is dispersed in the preparation in the form of suspended particles, which poses certain safety risks during intravenous injection; and it needs to be administered once a day, and there is no sustained release effect.

[0009] Chinese patent CN 113398096 A describes a long-acting injectable microsphere of meloxicam and its preparation method. The long-acting injectable microsphere can be sustained-released in vitro for more than 20 days. However, the drug release of the microsphere preparation is as high as 50% on day 1, followed by a slow release, with the release amount being about 90% on day 20. After injection, the blood drug concentration in the early stage of administration is likely to increase sharply, causing dose-related toxicity; while the drug release after 1 day is low, resulting in a low blood drug concentration in the later stage of administration, which is lower than the effective therapeutic concentration; in addition, the microsphere preparation has problems such as complex production process, high difficulty in production scale-up, and large differences in drug release behavior between batches.

[0010] Therefore, there is an urgent need to develop a meloxicam sustained-release injection that can be sustained-released for several days, has high drug safety, and has a formulation prescription process that is easy to industrialize, so as to achieve an analgesic effect for several days after a single administration; at the same time, avoid the use of meglumine and improve drug safety. Summary of the invention

[0011] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0012] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0013] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a meloxicam sustained-release injection.

[0014] In order to solve the above technical problems, the present invention provides the following technical solution: in terms of mass percentage of the meloxicam sustained-release injection, it comprises:

[0015] Meloxicam or its pharmaceutically acceptable salt 0.5-5%, biodegradable polymer 25-68%, drug release regulator 0-5%, solvent 5-60%;

[0016] Wherein, the biodegradable polymer is a mixture of sucrose acetate isobutyrate and lactide-glycolide copolymer.

[0017] As a preferred embodiment of the meloxicam sustained-release injection of the present invention, the mass ratio of sucrose acetate isobutyrate to the lactide-glycolide copolymer is 1:0 to 1:1.

[0018] As a preferred embodiment of the meloxicam sustained-release injection of the present invention, the drug release regulator comprises oleic acid.

[0019] As a preferred embodiment of the meloxicam sustained-release injection of the present invention, the solvent comprises one or more of 1-methyl-2-pyrrolidone, N,N-dimethylacetamide, benzyl alcohol, and anhydrous ethanol.

[0020] As a preferred embodiment of the meloxicam sustained-release injection of the present invention, the solvent comprises one or more of 1-methyl-2-pyrrolidone and N,N-dimethylacetamide.

[0021] As a preferred embodiment of the meloxicam sustained-release injection of the present invention, the in vitro sustained-release time of the meloxicam sustained-release injection is 5 to 7 days.

[0022] Another object of the present invention is to provide a method for preparing meloxicam sustained-release injection, comprising:

[0023] Meloxicam or its pharmaceutically acceptable salt is added to a solvent, and the mixture is stirred in a closed mechanical manner until dissolved. A biodegradable polymer and a drug release regulator are then added, and the mixture is stirred until all components are dissolved to form a clear, uniform viscous liquid. The obtained liquid is sterilized by a filter membrane to obtain a meloxicam sustained-release injection.

[0024] Another object of the present invention is to provide a drug for arthritis analgesia, comprising meloxicam sustained-release injection.

[0025] As a preferred embodiment of the arthritis analgesic drug of the present invention, the arthritis analgesic drug includes an arthritis postoperative analgesic drug and an arthritis attack period analgesic drug.

[0026] As a preferred embodiment of the drug for arthritis analgesia of the present invention, the arthritis includes rheumatoid arthritis, painful osteoarthritis, and acute arthritis of ankylosing spondylitis.

[0027] Beneficial effects of the present invention:

[0028] (1) The present invention adopts in situ reservoir technology to provide a meloxicam sustained-release injection, which contains an injectable solvent, a biodegradable sustained-release material, a release regulator, a drug and a polymer. After injection, an in situ reservoir is formed by phase transformation. The solvent diffuses from the reservoir to the injection site, and the drug is wrapped in the sustained-release material in the reservoir and slowly released to achieve a sustained-release effect, provide a long-term therapeutic effect, and can reduce the number of medications, reduce the fluctuation of blood drug concentration, and improve patient compliance.

[0029] (2) Compared with the commercially available preparation Mobic, the meloxicam sustained-release injection of the present invention has a significant sustained-release effect and can be released slowly. A single administration can achieve a sustained-release effect of 5 to 7 days, thereby reducing adverse reactions and the number of injections and improving patient compliance.

[0030] (3) The meloxicam sustained-release injection of the present invention has simple components, is easy to prepare, and has low cost; the preparation method provided by the present invention is simple, easy to perform, and takes a short time, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0032] Figure 1 This is the blood concentration-time curve of the commercially available preparation in beagle dogs.

[0033] Figure 2 The figure is the blood drug concentration-time curve of the injection solution of Example 1 of the present invention in beagle dogs.

[0034] Figure 3 The figure is the blood drug concentration-time curve of the injection of Example 4 of the present invention in beagle dogs.

[0035] Figure 4The blood drug concentration-time curve of the injection of Example 6 of the present invention in beagle dogs DETAILED DESCRIPTION

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0038] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0039] Unless otherwise specified, the raw materials used in the present invention are all commercially available in the art.

[0040] The corresponding relationship between the abbreviations and Chinese names of the raw materials in the present invention is as follows:

[0041] NMP: 1-methyl-2-pyrrolidone;

[0042] DMAC: N,N-dimethylacetamide;

[0043] SAIB: sucrose acetate isobutyrate;

[0044] PLGA: poly(lactide-co-glycolide);

[0045] The freeze-thaw test method of the meloxicam sustained-release injection of the present invention is as follows:

[0046] Weigh 1 g of meloxicam sustained-release injection into a vial and seal it with a roll cap. Place the vial at -20°C, take it out after 24 hours and place it at room temperature to observe whether the drug precipitates.

[0047] The method for determining the release rate of meloxicam sustained-release injection of the present invention is as follows:

[0048] The drug release was determined by the shaking table method, with 10 mL of PBS buffer at pH = 7.4 as the release medium, the medium temperature was 37°C ± 0.5°C, and the rotation speed was 100 rpm. 0.05 g of the preparation was added to a centrifuge tube containing the release medium, and the tube was placed in a water bath constant temperature oscillator for gyratory oscillation. Each sample was paralleled to 3 times, and all the release medium (10 ml) was taken out at 2h, 12h, 1d, 2d, 3d, 4d, and 5d, and an equal amount of fresh medium at the same temperature was added at the same time;

[0049] The sample is filtered through a 0.45μm microporous filter membrane, and the peak area of ​​the filtrate is determined by high performance liquid chromatography with a detection wavelength of 363nm. Accurately weigh an appropriate amount of reference substance and determine it in the same way. The cumulative release rate is calculated by the external standard method and should comply with regulations.

[0050] Example 1

[0051] This embodiment provides a meloxicam sustained-release injection and a preparation method thereof, specifically:

[0052] 1) Meloxicam sustained-release injection formula:

[0053] 3% meloxicam, 55% SAIB (biodegradable polymer), 42% NMP;

[0054] 2) Preparation method: 0.3 g of meloxicam is added to 4.2 g of NMP, and the mixture is stirred in a closed mechanical manner until dissolved. 5.5 g of SAIB is added to the preparation, and the mixture is stirred at room temperature until all components are completely dissolved to form a clear, uniform viscous liquid. The obtained liquid is passed through a sterilizing filter membrane, and sealed in a packaging material under nitrogen protection to obtain a meloxicam sustained-release injection.

[0055] Example 2

[0056] The difference between this embodiment and embodiment 1 is that the solvent formula is adjusted (see Table 1 for details), and freeze-thaw experiments and in vitro release experiments are performed on meloxicam sustained-release injections with different solvent formulas. The results are shown in Tables 1 and 2.

[0057] Table 1 Freeze-thaw test results of meloxicam sustained-release injection with different formulations

[0058]

[0059]

[0060] As can be seen from Table 1, when the solvent is NMP, the drug does not precipitate; when the ratio of DMAC, benzyl alcohol, and anhydrous ethanol exceeds 10%, the drug precipitates, because the solubility of the drug decreases due to the use of a mixed solvent, thereby causing the drug to precipitate.

[0061] The in vitro release test was performed on the formulation that did not precipitate in the freeze-thaw experiment. The results are shown in Table 2.

[0062] Table 2 In vitro release data under different solvent formulations

[0063]

[0064] As can be seen from Table 2, the release rates of the formulations using different mixed solvents are similar, indicating that the use of mixed solvents has little effect on the release.

[0065] Example 3

[0066] The difference between this embodiment and embodiment 1 is that the content of SAIB is adjusted (see Table 3 for details), and freeze-thaw experiments and in vitro release experiments are performed on meloxicam sustained-release injections with different SAIB contents. The results are shown in Tables 3 and 4.

[0067] Table 3 Freeze-thaw test results of meloxicam sustained-release injection with different formulations

[0068]

[0069] Table 4 In vitro release data of meloxicam sustained-release injection with different formulations

[0070]

[0071] It can be seen from Tables 3 and 4 that SAIB concentration has a significant effect on drug release. When the SAIB concentration is 85%, the release rate of API is slow, and the drug precipitates in the freeze-thaw experiment. When the SAIB concentration is 25% to 68%, it has a sustained release effect.

[0072] Example 4

[0073] This example introduces the biodegradable polymer PLGA on the basis of Example 1, specifically:

[0074] 1) Meloxicam sustained-release injection formula:

[0075] 3% meloxicam, 27.5% SAIB + 27.5% PLGA, 42% NMP;

[0076] 2) Preparation method: 0.3 g of meloxicam is added to 4.2 g of solvent, and the mixture is stirred in a closed mechanical manner until dissolved. 2.75 g of SAIB and 2.75 g of PLGA are added to the preparation, and stirred at room temperature until all components are completely dissolved to form a clear, uniform viscous liquid. The obtained liquid is passed through a sterilizing filter membrane, and under nitrogen protection, it is sealed in a packaging material to obtain a meloxicam sustained-release injection.

[0077] Example 5

[0078] The difference between this embodiment and embodiment 4 is that the contents of SAIB and PLGA are adjusted (see Table 5 for details), and freeze-thaw experiments and in vitro release experiments are performed on meloxicam sustained-release injections with different contents of SAIB and PLGA. The results are shown in Tables 5 and 6.

[0079] Table 5 Freeze-thaw test results of meloxicam sustained-release injection with different formulations

[0080]

[0081] Table 6 In vitro release data of meloxicam sustained-release injection with different formulations

[0082]

[0083] According to the results of freeze-thaw experiments, as the proportion of PLGA increases, the drug release rate slows down. When the mass ratio of SAIB:PLGA is 1:2, the 5-day release rate is only 62.3%, which is too slow and incomplete.

[0084] Example 6

[0085] This example introduces oleic acid based on Example 4, specifically:

[0086] 1) Meloxicam sustained-release injection formula:

[0087] 3% meloxicam, 27.5% SAIB + 27.5% PLGA, 37% NMP + 5% oleic acid;

[0088] 2) Preparation method: 0.3 g of meloxicam is added with 3.7 g of NMP and 0.5 g of oleic acid, and the mixture is stirred in a closed mechanical container until dissolved. 2.75 g of SAIB and 2.75 g of PLGA are added to the preparation, and the mixture is stirred at room temperature until all components are completely dissolved to form a clear, uniform viscous liquid. The obtained liquid is passed through a sterilizing filter membrane, and sealed in a packaging material under nitrogen protection to obtain a meloxicam sustained-release injection.

[0089] Example 7

[0090] The difference between this embodiment and embodiment 6 is that the content of oleic acid is adjusted (see Table 7 for details), and freeze-thaw experiments and in vitro release experiments are performed on meloxicam sustained-release injections with different oleic acid contents. The results are shown in Tables 7 and 8.

[0091] Table 7 Freeze-thaw test results of meloxicam sustained-release injection with different formulations

[0092]

[0093] Table 8 In vitro release data of meloxicam sustained-release injection in different formulations

[0094]

[0095] The in vitro release results showed that the addition of oleic acid significantly reduced the amount of drug released on the first day, with little effect on the later drug release rate. It is expected that the blood drug concentration at the initial stage of administration can be reduced, avoiding adverse reactions caused by excessive blood drug concentration at the initial stage of administration.

[0096] Comparative Example 1

[0097] 1) Meloxicam sustained-release injection formula:

[0098] 3% meloxicam, 55% PLGA, 42% NMP;

[0099] 2) Preparation method: 0.3 g of meloxicam is added to 4.2 g of NMP, and the mixture is stirred in a closed mechanical manner until dissolved. 5.5 g of PLGA is added to the preparation, and the mixture is stirred at room temperature until all components are completely dissolved to form a clear, uniform viscous liquid. The obtained liquid is passed through a sterilizing filter membrane, and sealed in a packaging material under nitrogen protection to obtain a meloxicam sustained-release injection.

[0100] Comparative Example 2

[0101] Patent CN113398096 A is cited, a long-acting injectable microsphere containing meloxicam and its preparation method. The preparation method is as follows:

[0102] 800 mg PLGA was weighed and dissolved in 20 mL of dichloromethane, 110 mg of meloxicam was added thereto to obtain a meloxicam-PLGA suspension, and the suspension was ultrasonically dispersed at high speed (10000 r / min, 5 min); the meloxicam-PLGA dispersed solution was rapidly dropped into a 1% polyvinyl alcohol (PVA) aqueous solution, stirred and emulsified at 3000 r / min for 5 min, and rapidly transferred to 0.1% PVA, magnetically stirred for 6 h to remove dichloromethane, and the washed balls were collected through a 1000-1200 mesh sieve, and freeze-dried to obtain the finished meloxicam microspheres.

[0103] The in vitro release results of Comparative Example 1, Example 4, Example 6, Comparative Example 1, and Comparative Example 2 are shown in Table 9.

[0104] Table 9

[0105]

[0106] As can be seen from Table 9, the early burst release of Comparative Examples 1 and 2 is relatively high, the later drug release rate is extremely low, and the release period is long, which easily leads to excessively high blood drug concentration in the early stage after administration, and the blood drug concentration in the later stage of administration does not reach the effective therapeutic concentration level due to the slow drug release rate in the later stage.

[0107] Study on the pharmacokinetic properties of meloxicam sustained-release injection in beagle dogs

[0108] A four-preparation, single-dose, parallel experimental design was adopted, with a commercially available preparation (Mobic, 15 mg / 1.5 mL, Shanghai Boehringer Ingelheim Pharmaceuticals Co., Ltd.) as the control preparation, and the meloxicam sustained-release injection in Examples 1, 4, and 6 as the test preparations.

[0109] Eight healthy male beagle dogs weighing about 12 kg were randomly divided into four groups, with two dogs in each group. They were fasted for 12 hours before administration, but were allowed to drink water freely.

[0110] The commercially available preparation is administered once a day, 30 mg each time, for 2 consecutive days, by intramuscular injection;

[0111] Approximately 2 mL of blood samples were collected at 0min, 5min, 10min, 20min, 30min, 50min, 1h, 1.25h, 1.5h, 2h, 3h, 4h, 6h, 8h, 12h, 20h, and 24h after administration. The second administration was conducted 24h later, and blood samples were collected at 5min, 15min, 30min, 1h, 1.5h, 2h, 2.5h, 3h, 4h, 6h, 8h, 12h, 24h, 36h, 48h, 60h, and 72h after the second administration.

[0112] In the embodiment, the dosage is about 2 g, the dosage is 60 mg, and the drug is injected intramuscularly. About 2 mL of blood samples are collected at 5 min, 15 min, 30 min, 45 min, 1 h, 2 h, 4 h, 6 h, 8 h, 12 h, 1 d, 2 d, 3 d, 4 d, 5 d, 6 d, and 7 d after administration.

[0113] The blood samples were placed in heparinized centrifuge tubes and centrifuged at 4000 rpm for 10 min. The supernatant plasma was collected and stored at -70°C until analysis.

[0114] The blood drug concentration-time curves of meloxicam in beagle dogs of the commercially available preparation, Example 1, Example 4, and Example 6 are shown in Table 1. Figure 1 to Figure 4 .

[0115] The in vivo pharmacokinetic study in beagle dogs showed that, compared with the commercially available preparations, the Cmax of Examples 1, 4 and 6 was significantly reduced and the Tmax was prolonged. After 96 hours of two injections of the commercially available meloxicam preparations, the blood concentration was reduced to the minimum detection limit. After 168 hours of a single intramuscular injection of the drug solutions of Examples 1, 4 and 6, the blood concentration was reduced to the minimum detection limit, indicating that the in situ reservoir of meloxicam significantly prolonged the drug action time.

[0116] Secondly, the blood drug concentration of Example 1, Example 4, and Example 6 reached a peak at about 9 to 10 hours, and the peak time was significantly prolonged compared with the commercially available preparations, and the maximum blood drug concentration was reduced. Cmax decreased from 23.915±7.225 μg / mL after injection of the commercially available preparation to 21.49±2.95 μg / mL, 12.52±2.95 μg / mL, and 13.16±1.73 μg / mL, respectively, indicating that the blood drug concentration after intramuscular injection of the meloxicam in situ depot was more stable.

[0117] In summary, the present invention adopts in situ reservoir technology to provide a meloxicam sustained-release injection, which contains an injectable solvent, a biodegradable sustained-release material, a release regulator, a drug and a polymer. After injection, an in situ reservoir is formed by phase transformation, the solvent diffuses from the reservoir to the injection site, and the drug is wrapped in the reservoir by the sustained-release material and slowly released to achieve a sustained-release effect, provide a long-term therapeutic effect, and can reduce the number of medications, reduce the fluctuation of blood drug concentration, and improve patient compliance.

[0118] Compared with the commercially available preparation Mobic, the meloxicam sustained-release injection of the present invention has an obvious sustained-release effect, can be slowly released, and a single administration can achieve a sustained-release effect of 5 to 7 days, reduce adverse reactions and injection times, and improve patient compliance. The meloxicam sustained-release injection of the present invention has simple components, is easy to prepare, and has low cost; the preparation method provided by the present invention is simple, easy to operate, and takes a short time, and is suitable for industrial production.

[0119] It should be noted that the above embodiments are only used to illustrate the technical solutions 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 solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A meloxicam sustained-release injection, characterized in that: Measured in terms of mass percentage of the meloxicam sustained-release injection, it comprises: Meloxicam or its pharmaceutically acceptable salt 0.5-5%, biodegradable polymer 55%, drug release regulator 2-5%, solvent 37-40%; The drug release regulator is oleic acid, the biodegradable polymer is a mixture of sucrose acetate isobutyrate and lactide-co-glycolide copolymer in a mass ratio of 1:1, and the solvent is 1-methyl-2-pyrrolidone.

2. The meloxicam sustained-release injection according to claim 1, characterized in that: The in vitro sustained-release time of the meloxicam sustained-release injection is 5 to 7 days.

3. The method for preparing the meloxicam sustained-release injection according to claim 1, characterized in that: The method comprises the steps of adding meloxicam or a pharmaceutically acceptable salt thereof into a solvent, stirring the mixture in a closed mechanical manner until the mixture is dissolved, adding a biodegradable polymer and a drug release regulator, stirring the mixture until the components are dissolved to form a clear, uniform viscous liquid, and sterilizing the obtained liquid by filtering it through a membrane to obtain a meloxicam sustained-release injection.

4. A drug for arthritis analgesia, characterized in that: Including the meloxicam sustained-release injection according to claim 1.

5. The drug for arthritis analgesia according to claim 4, characterized in that: The arthritis analgesics include arthritis post-operative analgesics and arthritis attack analgesics.

6. The drug for arthritis analgesia according to claim 4, characterized in that: The arthritis includes rheumatoid arthritis, painful osteoarthritis, and acute arthritis of ankylosing spondylitis.

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