A levorotatory tetrahydropalmatine citrate, its preparation method and application

Abstract

This invention relates to a levotetrahydropalmatine citrate, its preparation method, and its applications, belonging to the field of pharmaceutical technology. This invention provides a levotetrahydropalmatine citrate. Studies have shown that compared to other salt forms, the citrate form of levotetrahydropalmatine significantly improves its solubility. Furthermore, research has confirmed that levotetrahydropalmatine citrate can significantly reduce drug relapse preferences, with efficacy comparable to or even better than the injectable form, without causing significant adverse reactions and exhibiting good safety. Simultaneously, the sedative effect of levotetrahydropalmatine citrate is far superior to other salt forms. In addition, levotetrahydropalmatine citrate has therapeutic effects on sleep disorders, effectively shortening sleep onset time, increasing sleep duration, and improving sleep quality. Therefore, the levotetrahydropalmatine citrate provided by this invention has broad application prospects in the preparation of drugs for sedation, analgesia, treatment of sleep disorders, and treatment of drug addiction.

Description

Technical Field

[0001] This invention relates to a levorotatory tetrahydropalmatine citrate, its preparation method, and its application, belonging to the field of pharmaceutical technology. Background Technology

[0002] Drug addiction has become a major problem posing a serious threat to public health. Drug addiction not only devastates an individual's physical and mental health but also incurs enormous social governance costs, including public safety, medical burdens, and family breakdown. Although various detoxification treatments are currently available, including drug-assisted detoxification and psychological and behavioral interventions, addicts still face an extremely high risk of relapse after detoxification. Existing withdrawal medications have the problems of high addiction risk and significant side effects.

[0003] Meanwhile, sleep disorders have become a prevalent health problem worldwide, encompassing various types such as insomnia, sleep apnea, circadian rhythm disorders, and hypersomnia. With the accelerated pace of life, increased social pressure, and widespread use of electronic devices, declining sleep quality is evident across all age groups, particularly among young people and the elderly. Epidemiological surveys show that approximately one-third of people will experience some form of sleep disorder in their lifetime. Long-term sleep deprivation or poor sleep quality not only severely impacts work efficiency and quality of life but is also closely related to the development of various psychosomatic illnesses, including cardiovascular disease, metabolic syndrome, and depression. Therefore, sleep disorders are not merely a medical issue but a crucial area of ​​public health that urgently requires attention.

[0004] However, numerous technical challenges remain in the diagnosis and treatment of sleep disorders. While existing diagnostic methods such as polysomnography (PSG) are considered the "gold standard," their application is limited by the unnatural testing environment, complex operation, and high cost. Furthermore, the pathological mechanisms of sleep disorders are not fully understood; the complex interactions between neural circuits, neurotransmitters, and genetic factors make precise subtyping and individualized treatment difficult in clinical practice. In terms of pharmacological treatment, commonly used sedative-hypnotic drugs suffer from dependence, side effects, and declining long-term efficacy; non-pharmacological interventions such as cognitive behavioral therapy also face challenges in promotion and adherence.

[0005] L-Tetrahydropalmatine is an isoquinoline alkaloid extracted from the traditional Chinese medicine Corydalis yanhusuo. As a dopamine receptor antagonist, it has sedative, analgesic, and hypnotic effects. It can block dopamine receptors in the striatum, nucleus accumbens, and regulate dopamine biosynthesis, inhibit the production of acidic protein in glial fibers of the brain, thereby protecting neurons damaged by drug abuse and alleviating protracted withdrawal symptoms. It can also effectively improve sleep disorders.

[0006] However, the free base of levotetrahydropalmatine has low polarity and is difficult to dissolve after oral administration, resulting in slow absorption and low bioavailability. The free base is also easily oxidized and degraded, especially in humid or light-exposed environments, leading to a short shelf life and demanding storage conditions. Furthermore, the free base is difficult to formulate into clinically needed dosage forms such as injections (requiring high water solubility) and oral solutions, limiting its application to a few solid dosage forms (such as ordinary tablets), and even then, disintegration and absorption are poor. Formulating levotetrahydropalmatine into salts can solve these problems to some extent. Currently, levotetrahydropalmatine salt formulations generally include hydrochloride, sulfate, and tartrate salts.

[0007] Levotetrahydropalmatine hydrochloride has been used to treat sleep onset disorders. However, due to its low solubility, it cannot be used as a sustained-release drug; it only promotes rapid sleep onset and cannot maintain a corresponding blood drug concentration throughout the sleep period. Therefore, using levotetrahydropalmatine hydrochloride to treat sleep onset disorders can lead to early awakening and inability to fall back asleep after waking. Furthermore, the solubility of levotetrahydropalmatine hydrochloride is significantly affected by pH, resulting in poor drug stability, unstable efficacy, and significant side effects.

[0008] Furthermore, existing oral formulations of levotetrahydropalmatine are relatively limited in form, primarily consisting of ordinary tablets or simple matrix-based sustained-release tablets, which generally suffer from difficulties in precisely controlling release behavior. On the one hand, ordinary tablets rapidly disintegrate and release drug in the gastrointestinal tract, making it difficult to maintain stable blood drug concentrations and requiring frequent dosing. On the other hand, existing sustained-release tablets are mostly single-layer matrix structures, relying solely on high-viscosity polymer materials to slow drug release, making it difficult to balance onset speed and long-term efficacy. There is also a lack of segmented and targeted release strategies designed for different gastrointestinal sites. Currently, there are few reports in the published literature on the systematic development of various drug delivery systems using levotetrahydropalmatine citrate as the active ingredient, including bilayer sustained-release tablets, extruded and spheroidized microcapsules, and multi-pH segmented release coated capsules. In particular, there is a lack of specific processes and repeatable in vitro release data for achieving stable drug release for more than 12 hours by controlling the ratio of immediate-release to sustained-release layers, microcapsule size and matrix materials, or through multi-layer functional coating. Therefore, it is necessary to design and optimize sustained-release tablets, sustained-release capsules, and multi-segment release coated capsules with different structural features for levotetrahydropalmatine citrate in order to obtain a diversified formulation system with controllable onset of action, designable release curves, and adaptability to different clinical drug needs. Summary of the Invention

[0009] To solve the above-mentioned technical problems, the present invention provides a levorotatory tetrahydropalmatine citrate, the structural formula of which is shown in formula (1): .

[0010] In one embodiment of the present invention, the preparation method of the L-tetrahydropalmatine citrate includes: reacting L-tetrahydropalmatine with citric acid in a solvent to form a salt, followed by evaporation and concentration, cooling and crystallization, filtration and washing and / or drying to obtain a solid product, and the obtained solid product is confirmed to have formed a salt by nuclear magnetic resonance.

[0011] In one embodiment of the present invention, the molar ratio of the levorotatory tetrahydropalmatine to citric acid is 1:1.

[0012] In one embodiment of the invention, the salt comprises a solid form.

[0013] In one embodiment of the present invention, the structural formula of the levorotatory tetrahydropalmatine is shown in formula (2); the structural formula of the citric acid is shown in formula (3): .

[0014] The present invention also provides a pharmaceutical composition comprising the aforementioned levotetrahydropalmatine citrate and pharmaceutically acceptable excipients.

[0015] In one embodiment of the present invention, the excipients include at least one of the following pharmaceutically acceptable solvents, solubilizers, co-solvents, emulsifiers, colorants, binders, disintegrants, fillers, lubricants, wetting agents, osmotic pressure regulators, stabilizers, flow aids, flavoring agents, preservatives, suspending agents, coating materials, fragrances, anti-adhesives, binding agents, penetration enhancers, pH adjusters, buffers, plasticizers, surfactants, thickeners, encapsulating agents, humectants, absorbents, diluents, flocculants and anti-flocculators, filter aids, release inhibitors, and film-forming materials.

[0016] In one embodiment of the present invention, the excipients include at least one of microcrystalline cellulose (MCC), pregelatinized starch, lactose, polyvinylpyrrolidone (PVP), hydroxypropyl methylcellulose (HPMC), talc, magnesium stearate, Eudragit L100, Eudragit S100, Eudragit RS / RL, and the plasticizer triacetin (TEC).

[0017] In one embodiment of the present invention, the dosage form of the pharmaceutical composition includes at least one of an oral formulation, a nasal spray formulation, and an injectable formulation.

[0018] In one embodiment of the present invention, the oral formulation includes a conventional formulation, a sustained-release formulation, and / or a controlled-release formulation.

[0019] In one embodiment of the present invention, the common preparation includes at least one of tablets, capsules, granules, and oral liquids.

[0020] In one embodiment of the present invention, the nasal spray formulation includes a nasal aerosol.

[0021] In one embodiment of the present invention, the administration method of the pharmaceutical composition includes oral administration, injection administration, and / or nasal administration.

[0022] In one embodiment of the present invention, the oral formulation is an oral sustained-release formulation, which is a bilayer tablet comprising an immediate-release layer and a sustained-release layer, wherein the sustained-release layer comprises hydroxypropyl methylcellulose (HPMC).

[0023] In one embodiment of the present invention, the oral formulation is an oral sustained-release formulation, which is a microcapsule. The microcapsule is prepared by an extrusion spheronization process, and the matrix of the microcapsule contains hydroxypropyl methylcellulose (HPMC) and / or microcrystalline cellulose (MCC).

[0024] In one embodiment of the present invention, the oral formulation is an oral sustained-release formulation, the oral sustained-release formulation is a coated formulation, and the coating component comprises a methacrylic acid copolymer material.

[0025] In one embodiment of the present invention, the methacrylic acid copolymer material comprises Eudragit L100, Eudragit S100, Eudragit RS and / or Eudragit RL.

[0026] The present invention also provides the use of the said levotetrahydropalmatine citrate or the said pharmaceutical composition in the preparation of a medicament having any of the following functions: (a) Sedation; (b) Analgesia; (c) Prevention and / or treatment of drug addiction; And / or, (d) prevent and / or treat sleep disorders.

[0027] In one embodiment of the present invention, the sleep disorder includes difficulty falling asleep, sleep maintenance disorder, and / or abnormal sleep structure.

[0028] In one embodiment of the present invention, the drug is able to promote NREM sleep recovery and / or REM sleep recovery in a sleep deprivation model, and has a statistically significant difference compared to the control group (p < 0.05).

[0029] In one embodiment of the present invention, the dosage form of the drug includes at least one of oral formulation, nasal spray formulation, and injectable formulation.

[0030] The present invention also provides a method for preparing the aforementioned levorotatory tetrahydropalmatine citrate, the method comprising: reacting levorotatory tetrahydropalmatine with citric acid in a solvent in an acid-base reaction to generate a salt, followed by evaporation and concentration, cooling and crystallization, filtration and washing and / or drying to obtain a solid product, wherein the obtained solid product is confirmed to have formed a salt by nuclear magnetic resonance.

[0031] In one embodiment of the present invention, the molar ratio of the levorotatory tetrahydropalmatine to citric acid is 1:1.

[0032] In one embodiment of the invention, the solvent includes water.

[0033] In one embodiment of the present invention, the citric acid comprises different hydrous crystal forms.

[0034] In one embodiment of the present invention, the citric acid is citric acid monohydrate with the molecular formula C6H8O7·H2O and a molecular weight of approximately 210.14 g / mol.

[0035] In one embodiment of the present invention, the acid-base reaction temperature is 20~40°C.

[0036] In one embodiment of the present invention, the acid-base reaction temperature is 20°C, 25°C, 30°C or 40°C.

[0037] In one embodiment of the present invention, the acid-base reaction is carried out under ultrasonic conditions.

[0038] In one embodiment of the present invention, the ultrasonic frequency is 10~16kHz.

[0039] In one embodiment of the present invention, the ultrasonic frequency is 10 kHz, 12 kHz, 14 kHz or 16 kHz.

[0040] In one embodiment of the present invention, the ultrasound time is 5 to 15 minutes.

[0041] In one embodiment of the present invention, the ultrasound time is 5 min, 8 min, 10 min, 12 min, 13 min or 15 min.

[0042] The technical solution of this invention has the following advantages: 1. This invention provides a citrate form of levotetrahydropalmatine. Compared with other salt forms, the citrate form of levotetrahydropalmatine described in this invention significantly improves the solubility of levotetrahydropalmatine, reaching 355 mg / mL. Furthermore, the citrate form of levotetrahydropalmatine described in this invention has a therapeutic effect on sleep disorders, effectively shortening sleep onset time, increasing sleep duration, and improving sleep quality. Although levotetrahydropalmatine hydrochloride preparations have been used to treat sleep onset disorders, due to their very low solubility, they cannot be used as sustained-release drugs. They can only induce sleep quickly and cannot maintain the corresponding blood drug concentration throughout the sleep period, leading to problems such as early awakening and inability to fall back asleep after waking. They also suffer from drawbacks such as poor drug stability, unstable efficacy, and significant side effects. The citrate form of levotetrahydropalmatine described in this invention treats sleep disorders by effectively shortening sleep onset time, increasing sleep duration, and improving sleep quality, with better results.

[0043] Furthermore, the levotetrahydropalmatine citrate provided by this invention can significantly reduce drug relapse preference, with efficacy comparable to or even better than the injectable formulation, without causing significant adverse reactions and exhibiting good safety. Simultaneously, the sedative effect of levotetrahydropalmatine citrate is far superior to other salts of levotetrahydropalmatine. Therefore, the levotetrahydropalmatine citrate provided by this invention has broad application prospects in the preparation of drugs for sedation, analgesia, and treatment of sleep disorders and drug addiction.

[0044] 2. The present invention also provides a pharmaceutical composition comprising the aforementioned levotetrahydropalmatine citrate and pharmaceutically acceptable excipients, wherein the dosage form of the pharmaceutical composition includes at least one of an oral formulation, a nasal spray formulation, and an injectable formulation.

[0045] Furthermore, the oral formulation is an oral sustained-release formulation, which is a bilayer tablet comprising an immediate-release layer and a sustained-release layer, and the sustained-release layer comprises hydroxypropyl methylcellulose (HPMC). This structure enables rapid onset of action and subsequent stable and sustained release of the drug, allowing levotetrahydropalmatine citrate to be released continuously over 8 to 12 hours, thereby improving bioavailability and reducing the frequency of administration.

[0046] Furthermore, the oral formulation is an oral sustained-release formulation, which is a microcapsule. The microcapsule is prepared by an extrusion spheroidization process. By uniformly dispersing the drug in a polymer matrix such as HPMC, a dense spherical microcapsule is formed, achieving a relatively stable sustained-release effect, which can achieve continuous release for 12 to 24 hours.

[0047] Furthermore, the oral formulation is an oral sustained-release formulation, which is a coated formulation, and the coating component includes a methacrylic acid copolymer material. The coated formulation is a multi-pH segmented-release coated capsule, which encapsulates the drug using a coating material dissolved under different pH conditions to form a segmented coating, achieving segmented release of the drug in the stomach, small intestine, and colon, with a release time of 12-18 hours. Attached Figure Description

[0048] Figure 1 The effect of levotetrahydropalmatine citrate on drug addiction; Figure 2 It is a sedative function test of L-tetrahydropalmatine citrate; Figure 3 It is a functional trial of L-tetrahydropalmatine citrate for the treatment of sleep disorders; Figure 4 It is a sedative function test of different salt forms of levotetrahydropalmatine; Figure 5 This is a functional trial of different salt forms of levotetrahydropalmatine for the treatment of sleep disorders; Figure 6 The effect of nasal administration of levotetrahydropalmatine citrate on the inhibition of drug addiction; Figure 7 This is a sedative efficacy test of levotetrahydropalmatine citrate administered via nasal administration; Figure 8 This is a functional trial of levotetrahydropalmatine citrate administered nasally for the treatment of sleep disorders. Detailed Implementation

[0049] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0050] For any experimental steps or conditions not specified in the following examples, the procedures or conditions described in the literature in this field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0051] The following examples involve materials sourced from MCE: L-tetrahydropalmatine, DMSO, citric acid, hydrochloric acid, methanesulfonic acid, glucuronic acid, malic acid, acetic acid, lactic acid, and tartaric acid.

[0052] Example 1: L-Tetrahydropalmatine Citrate and its Preparation Method This embodiment provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution and stir thoroughly to obtain a mixture; place the mixture in a 20℃ water bath and sonicate it at a frequency of 10 kHz for 15 minutes to carry out the reaction, and obtain a 1 mol / L L-tetrahydropalmatine citrate solution. 3) Freeze-dry a 1 mol / L solution of levorotatory tetrahydropalmatine citrate to obtain levorotatory tetrahydropalmatine citrate solid powder.

[0053] Example 2: L-Tetrahydropalmatine Citrate and its Preparation Method This embodiment provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution and stir thoroughly to obtain a mixture; place the mixture in a 20℃ water bath and sonicate it at a frequency of 12 kHz for 15 minutes to carry out the reaction, and obtain a 1 mol / L L-tetrahydropalmatine citrate solution. 3) Freeze-dry a 1 mol / L solution of levorotatory tetrahydropalmatine citrate to obtain levorotatory tetrahydropalmatine citrate solid powder.

[0054] Example 3: L-Tetrahydropalmatine Citrate and its Preparation Method This embodiment provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution and stir thoroughly to obtain a mixture; place the mixture in a 20℃ water bath and sonicate it at a frequency of 14 kHz for 13 minutes to carry out the reaction, and obtain a 1 mol / L L-tetrahydropalmatine citrate solution. 3) Freeze-dry a 1 mol / L solution of levorotatory tetrahydropalmatine citrate to obtain levorotatory tetrahydropalmatine citrate solid powder.

[0055] Example 4: L-Tetrahydropalmatine Citrate and its Preparation Method This embodiment provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution and stir thoroughly to obtain a mixture; place the mixture in a 20℃ water bath and sonicate it at a frequency of 16 kHz for 10 minutes to carry out the reaction, and obtain a 1 mol / L L-tetrahydropalmatine citrate solution. 3) Freeze-dry a 1 mol / L solution of levorotatory tetrahydropalmatine citrate to obtain levorotatory tetrahydropalmatine citrate solid powder.

[0056] Example 5: L-Tetrahydropalmatine Citrate and its Preparation Method This embodiment provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution and stir thoroughly to obtain a mixture; place the mixture in a 30℃ water bath and sonicate it at a frequency of 10 kHz for 15 minutes to carry out the reaction, and obtain a 1 mol / L L-tetrahydropalmatine citrate solution. 3) Freeze-dry a 1 mol / L solution of levorotatory tetrahydropalmatine citrate to obtain levorotatory tetrahydropalmatine citrate solid powder.

[0057] Example 6: L-Tetrahydropalmatine Citrate and its Preparation Method This embodiment provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution and stir thoroughly to obtain a mixture; place the mixture in a 30℃ water bath and sonicate it at a frequency of 12 kHz for 13 minutes to carry out the reaction, and obtain a 1 mol / L L-tetrahydropalmatine citrate solution. 3) Freeze-dry a 1 mol / L solution of levorotatory tetrahydropalmatine citrate to obtain levorotatory tetrahydropalmatine citrate solid powder.

[0058] Example 7: L-Tetrahydropalmatine Citrate and its Preparation Method This embodiment provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution and stir thoroughly to obtain a mixture; place the mixture in a 30℃ water bath and sonicate it at a frequency of 14 kHz for 12 minutes to carry out the reaction, and obtain a 1 mol / L L-tetrahydropalmatine citrate solution. 3) Freeze-dry a 1 mol / L solution of levorotatory tetrahydropalmatine citrate to obtain levorotatory tetrahydropalmatine citrate solid powder.

[0059] Example 8: L-Tetrahydropalmatine Citrate and its Preparation Method This embodiment provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution and stir thoroughly to obtain a mixture; place the mixture in a 30℃ water bath and sonicate it at a frequency of 16 kHz for 8 minutes to carry out the reaction, and obtain a 1 mol / L L-tetrahydropalmatine citrate solution. 3) Freeze-dry a 1 mol / L solution of levorotatory tetrahydropalmatine citrate to obtain levorotatory tetrahydropalmatine citrate solid powder.

[0060] Example 9: L-Tetrahydropalmatine Citrate and its Preparation Method This embodiment provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution and stir thoroughly to obtain a mixture; place the mixture in a 40℃ water bath and sonicate it at a frequency of 10 kHz for 15 minutes to carry out the reaction, and obtain a 1 mol / L L-tetrahydropalmatine citrate solution. 3) Freeze-dry a 1 mol / L solution of levorotatory tetrahydropalmatine citrate to obtain levorotatory tetrahydropalmatine citrate solid powder.

[0061] Example 10: L-Tetrahydropalmatine Citrate and its Preparation Method This embodiment provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution and stir thoroughly to obtain a mixture; place the mixture in a 40℃ water bath and sonicate it at a frequency of 12 kHz for 12 minutes to carry out the reaction, and obtain a 1 mol / L L-tetrahydropalmatine citrate solution. 3) Freeze-dry a 1 mol / L solution of levorotatory tetrahydropalmatine citrate to obtain levorotatory tetrahydropalmatine citrate solid powder.

[0062] Example 11: L-Tetrahydropalmatine Citrate and its Preparation Method This embodiment provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution and stir thoroughly to obtain a mixture; place the mixture in a 40℃ water bath and sonicate it at a frequency of 14 kHz for 10 minutes to carry out the reaction, and obtain a 1 mol / L L-tetrahydropalmatine citrate solution. 3) Freeze-dry a 1 mol / L solution of levorotatory tetrahydropalmatine citrate to obtain levorotatory tetrahydropalmatine citrate solid powder.

[0063] Example 12: L-Tetrahydropalmatine Citrate and its Preparation Method This embodiment provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution and stir thoroughly to obtain a mixture; place the mixture in a 40℃ water bath and sonicate it at a frequency of 16 kHz for 5 minutes to carry out the reaction, and obtain a 1 mol / L L-tetrahydropalmatine citrate solution. 3) Freeze-dry a 1 mol / L solution of levorotatory tetrahydropalmatine citrate to obtain levorotatory tetrahydropalmatine citrate solid powder.

[0064] Example 13: L-Tetrahydropalmatine Citrate and its Preparation Method This embodiment provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution and stir thoroughly to obtain a mixture; place the mixture in a water bath at room temperature (25℃) and sonicate it at a frequency of 10 kHz for 15 minutes to carry out the reaction, and obtain a 1 mol / L L-tetrahydropalmatine citrate solution. 3) Freeze-dry a 1 mol / L solution of levorotatory tetrahydropalmatine citrate to obtain levorotatory tetrahydropalmatine citrate solid powder.

[0065] Example 14: L-Tetrahydropalmatine Citrate Sustained-Release Tablets and Their Preparation Method This embodiment provides a levotetrahydropalmatine citrate sustained-release tablet, comprising a bilayer tablet structure of an immediate-release layer and a sustained-release layer. The bilayer tablet structure aims to achieve rapid onset of action and subsequent stable and sustained release of the drug, improving bioavailability and reducing dosing frequency. The specific preparation method of the levotetrahydropalmatine citrate sustained-release tablet is as follows: 1) Composition of raw and auxiliary materials Immediate-release layer: L-Tetrahydropalmatine Citrate: 15% of the total weight of tablets Microcrystalline cellulose (MCC): 30 wt% Pregelatinized starch: 20 wt% Lactose: 30 wt% Polyvinylpyrrolidone (PVP, added as a 5% aqueous solution): 5% of dry weight Sustained-release layer: L-Tetrahydropalmatine citrate: 15 wt% Hydroxypropyl methylcellulose (HPMC, viscosity 100,000 mPa·s): 60 wt% Microcrystalline cellulose: 23 wt% Talc or magnesium stearate: 2 wt% 2) Preparation steps Step A: Preparation of the immediate-release layer (1) Mix L-tetrahydropalmatine citrate, microcrystalline cellulose, starch and lactose through an 80-mesh sieve until homogeneous; (2) Dissolve PVP in purified water according to the formula to prepare a 5 wt% adhesive solution; (3) Place the above powder in a high shear granulator and spray in PVP solution to granulate; (4) Place the wet granules in a fluidized bed dryer and dry at 60°C until the moisture content is <3 wt%; (5) Grind the particles to 16 mesh and add an appropriate amount of talcum powder and mix well.

[0066] Step B: Preparation of sustained-release layer (1) Mix L-tetrahydropalmatine citrate with HPMC and MCC in a certain proportion; (2) Direct tableting can be used for granulation, or a small amount of ethanol-water mixture can be sprayed for wet granulation. (3) After drying, granulate and add magnesium stearate for lubrication.

[0067] Step C: Tableting (1) A double-layer tablet press is used, with the sustained-release powder as the lower layer filler; (2) Then add the immediate-release powder as the top layer; (3) The tablets are compressed into a double-layer sustained-release tablet with a total weight of 500 mg.

[0068] 3) Release mechanism After compression, the immediate-release layer rapidly disintegrates and releases the drug in gastric juice, while the sustained-release layer contains HPMC that swells upon contact with water to form a gel barrier, controlling the continuous release of L-tetrahydropalmatine citrate over 8 to 12 hours through diffusion and dissolution mechanisms.

[0069] Example 15: L-Tetrahydropalmatine Citrate Sustained-Release Capsules (Extruded Spheroidized Microspheres) and Their Preparation Method This embodiment provides a levotetrahydropalmatine citrate sustained-release microcapsule capsule, prepared using an extrusion spheroidization process. By uniformly dispersing the drug in a polymer matrix (e.g., HPMC), dense spherical microcapsules are formed, achieving a relatively stable sustained-release effect. The specific preparation method of the levotetrahydropalmatine citrate sustained-release microcapsule capsule is as follows: 1) Composition of raw and auxiliary materials L-Tetrahydropalmatine citrate: 15 wt% HPMC (medium to high viscosity): 60 wt% Microcrystalline cellulose (MCC, PH101): 25 wt% Appropriate amount of purified water for wet granulation 2) Preparation steps (1) Sieve and mix L-tetrahydropalmatine citrate, MCC and HPMC; (2) Slowly add purified water to mix into a wet soft material. The moisture content should be such that it can be formed into a ball by hand and broken when released. (3) Feed the wet soft material into the extruder and extrude it using a 1.0 mm orifice diameter; (4) The extruded wet strips are immediately fed into a rounding machine and rounded at 300-500 rpm for 10-20 minutes to obtain round micro pellets with a particle size of about 1 mm. (5) Dry in a hot air circulating drying oven at 40~50℃ until the water content is <3 wt%; (6) Screen the particle size and fill the capsules according to the amount required for No. 0 capsules.

[0070] 3) Structural features The microparticle structure allows the drug to be eroded by the body fluid in the digestive tract at a uniform rate, is less affected by gastric emptying, and has a more stable release curve, enabling continuous release for 12 to 24 hours.

[0071] Example 16: Multi-pH fractional-release coated capsules of L-tetrahydropalmatine citrate and their preparation method This embodiment provides a multi-layered pH-sensitive coating-based segmented-release capsule of levotetrahydropalmatine citrate. By using coating materials dissolved under different pH conditions to encapsulate the drug, a segmented coating is formed, enabling segmented release of the drug in the stomach, small intestine, and colon. The specific preparation method of the levotetrahydropalmatine citrate segmented-release capsule is as follows: 1) Core Particle Preparation Using the powder formulation of the immediate-release layer in Example 13, 18-24 mesh particles were prepared by wet granulation and then dried in a fluidized bed at 40°C.

[0072] 2) Segmented coating formula Coating A (Enteric Coating): Eudragit L100 (dissolves at pH ≈ 6.0) Coating B (delayed release layer): Eudragit S100 (dissolved at pH ≈ 7.0) Coating C (Sustained-release layer): Eudragit RS / RL, HPMC, Plasticizer (TEC) The coating solution contains 10 wt% plasticizer triacetyl ester (TEC) and 5 wt% talc.

[0073] 3) Preparation steps Add immediate-release granules to a fluidized bed spray coating device; Spray coating A makes the particles insoluble in the stomach at pH (1~3), and releases 20~30% of the drug after entering the small intestine; Continue spraying coating B to keep the particles stable in the anterior small intestine until the pH of the ileum / colon is >7 before releasing the second stage of the drug; The outer layer is coated with coating C to form a sustained-release layer that further delays release; Dry to a moisture content of <3 wt%, and after screening for qualified granules, fill into No. 0 or No. 1 capsules.

[0074] 4) Release characteristics In vitro dissolution tests confirmed that the particles showed no significant release after 2 hours in a pH 1.2 environment; approximately 30% was released in a pH 6.8 phosphate buffer solution; and the remaining drug was continuously released under pH 7.4 conditions, with a release time of 12-18 hours.

[0075] Comparative Examples 1-7: Different Salt Forms of Levotetrahydropalmatine and Their Preparation Methods This comparative example provides different salt forms of L-tetrahydropalmatine, and the preparation steps for these different salt forms are as follows: 1) Preparation of 1 mol / L acid solution: Weigh 1 mol of solid powder of hydrochloric acid, methanesulfonic acid, glucuronic acid, malic acid, acetic acid, lactic acid and tartaric acid respectively and dissolve them in 1 L of pure water to obtain 1 mol / L acid solution; 2) Preparation of different salt forms of levotetrahydropalmatine formulations: Weigh out levotetrahydropalmatine solid powder in batches and add it to 1 mL of the 1 mol / L acid solution prepared above. Stir thoroughly until the levotetrahydropalmatine solid powder cannot be dissolved to obtain a mixture. Place the mixture in a water bath at room temperature (25℃) and sonicate it at a frequency of 10 kHz for 15 minutes to carry out the reaction, thereby obtaining different salt forms of levotetrahydropalmatine formulations. 3) Freeze-dry the formulation solutions of different salts of levotetrahydropalmatine to obtain solid powders of different salts of levotetrahydropalmatine (levotetrahydropalmatine hydrochloride, levotetrahydropalmatine mesylate, levotetrahydropalmatine glucuronide, levotetrahydropalmatine malate, levotetrahydropalmatine acetate, levotetrahydropalmatine lactate, and levotetrahydropalmatine tartrate).

[0076] Comparative Examples 8-14: Different Salt Forms of Levotetrahydropalmatine and Their Preparation Methods This comparative example provides different salt forms of L-tetrahydropalmatine, and the preparation steps for these different salt forms are as follows: 1) Preparation of 2 mol / L acid solution: Weigh 2 mol of solid powder of hydrochloric acid, methanesulfonic acid, glucuronic acid, malic acid, acetic acid, lactic acid and tartaric acid respectively and dissolve them in 1 L of pure water to obtain 2 mol / L acid solution; 2) Preparation of different salt forms of levotetrahydropalmatine formulations: Weigh out levotetrahydropalmatine solid powder in batches and add it to 1 mL of the 2 mol / L acid solution prepared above. Stir thoroughly until the levotetrahydropalmatine solid powder cannot be dissolved to obtain a mixture. Place the mixture in a water bath at room temperature (25℃) and sonicate it at a frequency of 10 kHz for 15 minutes to carry out the reaction, thereby obtaining different salt forms of levotetrahydropalmatine formulations. 3) Freeze-dry the formulation solutions of different salts of levotetrahydropalmatine to obtain solid powders of different salts of levotetrahydropalmatine (levotetrahydropalmatine hydrochloride, levotetrahydropalmatine mesylate, levotetrahydropalmatine glucuronide, levotetrahydropalmatine malate, levotetrahydropalmatine acetate, levotetrahydropalmatine lactate, and levotetrahydropalmatine tartrate).

[0077] Comparative Example 15: L-Tetrahydropalmatine Citrate and its Preparation Method This comparative example provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution. Stir thoroughly at room temperature (25℃). The reaction is incomplete and citric acid is in excess, resulting in a mixed solution of citric acid and L-tetrahydropalmatine citrate.

[0078] Comparative Example 16: L-Tetrahydropalmatine Citrate and its Preparation Method This comparative example provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution to obtain a mixture. Place the mixture in a 40℃ water bath and stir thoroughly. The reaction is incomplete and citric acid is in excess, resulting in a mixed solution of citric acid and L-tetrahydropalmatine citrate.

[0079] Comparative Example 17: L-Tetrahydropalmatine Citrate and its Preparation Method This comparative example provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution to obtain a mixture. Place the mixture in a 50℃ water bath and stir thoroughly. If the reaction is incomplete and citric acid is in excess, a mixed solution of citric acid and L-tetrahydropalmatine citrate is obtained.

[0080] Comparative Example 18: L-Tetrahydropalmatine Citrate and its Preparation Method This comparative example provides a levorotatory tetrahydropalmatine citrate, the preparation steps of which are as follows: 1) Preparation of 1 mol / L citric acid solution: Weigh 1 mol of citric acid solid powder and dissolve it in 1 L of pure water to obtain a 1 mol / L citric acid solution; 2) Preparation of L-tetrahydropalmatine citrate solution: Weigh 355 mg of L-tetrahydropalmatine and add it to 1 mL of 1 mol / L citric acid solution to obtain a mixture. Place the mixture in a 60℃ water bath and stir thoroughly. If the reaction is incomplete and citric acid is in excess, a mixed solution of citric acid and L-tetrahydropalmatine citrate is obtained.

[0081] Experimental Example 1: Effect of different dissolution conditions on the solubility of levotetrahydropalmatine This experiment determined the solubility of the levorotatory tetrahydropalmatine citrate prepared by the methods shown in Examples 1-13 and Comparative Examples 15-18. The specific steps are as follows: Solubility determination method: Weigh out solid powder of levotetrahydropalmatine in batches, and obtain the solubility of levotetrahydropalmatine citrate under different dissolution conditions based on the number of grams of completely dissolved levotetrahydropalmatine.

[0082] The results showed that the solubility of L-tetrahydropalmatine citrate varied under different dissolution temperatures and ultrasonic conditions. The highest solubility was 125 mg / mL in the group that was stirred and allowed to stand at room temperature (Comparative Example 15), 135 mg / mL in the group that was heated and stirred at 40°C (Comparative Example 16), 139 mg / mL in the group that was heated and stirred at 50°C (Comparative Example 17), and 140 mg / mL in the group that was heated and stirred at 60°C (Comparative Example 18). The highest solubility was 355 mg / mL after ultrasonic-assisted dissolution with thorough stirring at 20°C to 40°C (Examples 1 to 12), and the highest solubility reached 400 mg / mL after ultrasonic-assisted dissolution with thorough stirring at room temperature (Example 13). Regarding the ratio of L-tetrahydropalmatine to citrate, since pure L-tetrahydropalmatine citrate was required, equimolar amounts of citric acid and L-tetrahydropalmatine could be used, i.e., L-tetrahydropalmatine citrate could be prepared according to the preparation methods of Examples 1 to 13.

[0083] Experimental Example 2: Effect of Salt Form on the Solubility of Levotetrahydropalmatine This experiment determined the solubility of different salts of levotetrahydropalmatine in Examples 1-13 and Comparative Examples 1-7. The specific steps are as follows: Solubility determination method: Weigh out solid powder of levotetrahydropalmatine in batches, and obtain the solubility of different salt forms of levotetrahydropalmatine based on the number of grams of completely dissolved levotetrahydropalmatine.

[0084] The results showed that the solubility of different salts of L-tetrahydropalmatine varied. In an acid solution of 1 mol / L, the solubility of L-tetrahydropalmatine citrate was 355 mg / mL (Examples 1-13), the solubility of hydrochloride was 35 mg / mL, the solubility of methanesulfonate was 121.5 mg / mL, the solubility of glucuronate was 69 mg / mL, the solubility of malate was 50 mg / mL, the solubility of acetate was 55 mg / mL, the solubility of lactate was 5 mg / mL, and the solubility of tartrate was 4 mg / mL (Comparative Examples 1-7).

[0085] Experiment Example 3: Effect of acid concentration on the solubility of different salt forms of levotetrahydropalmatine This experiment determined the solubility of different salts of levotetrahydropalmatine in Comparative Examples 8-14. The specific steps are as follows: Solubility determination method: Weigh out solid powder of levotetrahydropalmatine in batches, and obtain the solubility of different salt forms of levotetrahydropalmatine based on the number of grams of completely dissolved levotetrahydropalmatine.

[0086] The results showed that the solubility of L-tetrahydropalmatine salts varied with different acid concentrations. When the acid solution was 2 mol / L, the solubility of L-tetrahydropalmatine hydrochloride was 42 mg / mL, that of methanesulfonate was 129 mg / mL, that of glucuronate was 71 mg / mL, that of malate was 50 mg / mL, that of acetate was 55 mg / mL, that of lactate was 5 mg / mL, and that of tartrate was 4 mg / mL (Comparative Examples 8–14).

[0087] Experiment Example 4: Effects of L-Tetrahydropalmatine Citrate on Drug Addiction This experimental example provides the effect of L-tetrahydropalmatine citrate on drug addiction in Example 1. The experimental procedure is as follows: 1. Experimental Design: The CPP score (residual time on the drug-treated side minus residual time on the non-drug-treated side) was used to measure the relapse preference of mice for drugs; a higher score indicates stronger dependence. Experimental groups included: ① Saline + Saline control group; ② Methamphetamine (METH) + saline positive control group (significant relapse behavior); ③ Methamphetamine (METH) + L-tetrahydropalmatine citrate group; ④ Methamphetamine (METH) + L-tetrahydropalmatine DMSO solution.

[0088] 2. Preparation of mice: 7-week-old male C57BL / 6J mice (purchased from Vital Rivers).

[0089] 3. Experimental steps: (1) Pre-test (Day 1): Training for 15 minutes. Based on the pre-test results, the non-natural preference box of the mice was selected as the drug-accompanied side, and the natural preference box was selected as the non-drug-accompanied side. Mice with a single-sided dwell time of more than 600 s or fewer than 20 shuttles were removed.

[0090] (2) CPP training (Day 2-9) (Acquisition of METH associative memory) On the first day, mice were injected intraperitoneally with 1 mg / kg of METH (dissolved in physiological saline), and immediately placed on the drug-treated side for 40 minutes for training. The next day, mice were injected intraperitoneally with saline solution and immediately placed on the non-drug-treated side for 40 minutes for training. Two days constituted one training cycle, and a total of four training cycles were conducted.

[0091] (3) Post-test1 (Day 10) (Retrieval of METH-related memories) The test lasted 15 minutes, and the time the mice spent in the two boxes was recorded. CPP score = time spent on the drug-treated side - time spent on the non-drug-treated side. Mice that did not acquire METH-associated memory were excluded based on the results.

[0092] (4) Extinction of METH-associated memory (7 days): Mice were randomly divided into 4 groups, and their weight was measured. Based on their weight, 10 mg / kg of the intervention drug (dissolved in physiological saline) was injected intraperitoneally. Depending on the experimental group, physiological saline, levotetrahydropalmatine citrate solution (dissolved in physiological saline) or levotetrahydropalmatine DMSO solution were injected before 10:00 am every day for 7 consecutive days, once a day. After administration, the mice were returned to their cages.

[0093] (5) Relapse (METH-associated memory re-retrieval triggered by drug cues): Immediately after injection of 1 mg / kg METH, the mice were tested for 15 min and the time spent in the two boxes was recorded. CPP score = time spent by the mouse on the drug-treated side - time spent by the mouse on the non-drug-treated side.

[0094] 4. Experimental Results: The experimental results are attached. Figure 1 As shown in the results, the intraperitoneal injection group of levotetrahydropalmatine citrate (group ③) significantly reduced relapse preference for methamphetamine, with efficacy comparable to or even better than the injectable formulation (group ④) (p<0.01). Levotetrahydropalmatine is extremely poorly soluble; therefore, to achieve an injection concentration of 10 mg / kg, levotetrahydropalmatine DMSO solution is usually administered intraperitoneally to mice. However, dimethyl sulfoxide (DMSO) is a highly polar, strongly permeable, and flammable liquid that can rapidly penetrate the skin and carry co-dissolved toxins into the body; inhalation / ingestion and contact with the eyes can cause irritation, dizziness, etc., and long-term high doses pose reproductive and developmental risks, making it unsuitable for human use. Based on the above experimental results, the injection of levotetrahydropalmatine citrate solution dissolved in physiological saline has an effect comparable to that of the levotetrahydropalmatine-DMSO group in inhibiting relapse preference, and requires no organic solvent carrier, with no DMSO-related toxicity risks observed, significantly improving drug safety.

[0095] Experimental Example 5: Sedative Function Test of L-Tetrahydropalmatine Citrate This experimental example provides a sedative function test of the levonorgestrel citrate in Example 1. The experimental procedure is as follows: 1. Experimental Design: The total distance of movement in mice after injection was used to measure the mice's motor response to the drug and the increase in addiction; a higher value indicated a stronger addiction. The behavior box (purchased from Shanghai Ruanxin Company) measured 44×44 cm, with a central area of ​​22×22 cm. Experimental groups included: ① Saline + Saline control group; ② Methamphetamine (METH) + saline positive control group (significantly enhanced exercise); ③ Methamphetamine (METH) + L-tetrahydropalmatine citrate group; ④ Methamphetamine (METH) + L-tetrahydropalmatine DMSO solution group.

[0096] 2. Experimental steps: (1) Overall schedule: Day 1 (Adaptation): Move the mice into the behavior room for 30 min to adapt → put them in the behavior box (open field) for 30 min to run (without injection) → return them to their cages.

[0097] Day 2: Adapt to the behavior room for 30 min → Place the mouse in the behavior box for 30 min (baseline) → Remove the mouse and inject it with methamphetamine 1 mg / kg (ip) → Immediately return it to the box and record for 60 min (post-injection).

[0098] Days 3-7: Repeat Day 2 steps daily, adjusting the methamphetamine (dissolved in saline) dose to 5 mg / kg (ip).

[0099] Day 8: Same as Day 2, but the methamphetamine dosage is adjusted to 1 mg / kg (ip).

[0100] Withdrawal period: Day 9 to Day 22: Intraperitoneal injection of 15 mg / kg of normal saline, levotetrahydropalmatine citrate solution (dissolved in normal saline), or levotetrahydropalmatine DMSO solution, and daily health monitoring.

[0101] Day 26 (Challenge): On day 26, inject methamphetamine 1 mg / kg (ip), following the same procedure as Day 2 (i.e., 30 min adaptation → 30 min baseline → injection → 60 min recording).

[0102] (2) Main observation indicators: Total distance after injection: total distance traveled within 60 minutes.

[0103] 3. Experimental Results: The experimental results are attached. Figure 2 As shown. By Figure 2The results showed that the total distance traveled by mice in the methamphetamine + saline positive control group (group ②) was significantly higher than that in the saline + saline control group (group ①) within 60 minutes after injection, with the average distance increasing from approximately 1100 cm to over 2000 cm (P < 0.0001), indicating that methamphetamine can significantly induce hyperkinesis and addiction-related behaviors in mice. In contrast, the total distance traveled by mice in the methamphetamine + L-tetrahydropalmatine citrate group (group ③) was significantly lower than that in the methamphetamine + saline group (group ②), decreasing to approximately 1200 cm, close to the level of the saline control group, indicating that L-tetrahydropalmatine citrate can significantly inhibit methamphetamine-induced hyperkinesis. Furthermore, the activity distance in the methamphetamine + levotetrahydropalmatine DMSO solution group (group ④) was also significantly lower than that in the methamphetamine + saline group (group ②), but there was no significant difference compared to the levotetrahydropalmatine citrate group (group ③). This indicates that the sedative / anti-hyperkinesia effects of levotetrahydropalmatine are basically consistent under different solvent forms, and DMSO as a solvent does not significantly interfere with the efficacy. However, since DMSO is not suitable for human use, saline was used as a solvent to dissolve levotetrahydropalmatine citrate for sedation.

[0104] Based on the above data, it is evident that the levotetrahydropalmatine citrate used in this invention, after continuous administration during the withdrawal period, significantly reduced the total distance traveled by mice upon methamphetamine rechallenge, weakened their behavioral response to methamphetamine, and demonstrated a good sedative effect and potential for improving excitatory addictive behavior. Furthermore, the intraperitoneal injection group of levotetrahydropalmatine citrate exhibited the same sedative effect as the intraperitoneal injection group of levotetrahydropalmatine DMSO.

[0105] Experiment Example 6: Functional Trial of L-Tetrahydropalmatine Citrate in the Treatment of Sleep Disorders This experimental example provides a functional trial of the treatment of sleep disorders with L-tetrahydropalmatine citrate in Example 1. The experimental procedure is as follows: 1. Experimental Design: A sleep deprivation experiment was designed to record the NREM (non-rapid eye movement) and REM (rapid eye movement) sleep times of mice to measure sleep disturbance. Lower values ​​indicated a significant increase in wakefulness, suggesting the mice were in a state of sleep disorder. Experimental groups included: ① Blank behavior + saline (blank control group); ② Chronic sleep deprivation + saline solution (sleep deprivation model group); ③ Chronic sleep deprivation + L-tetrahydropalmatine citrate (L-tetrahydropalmatine citrate treatment group); ④ Chronic sleep deprivation + melatonin (positive control group) 2. Experimental steps: Day 14|EEG / EMG Implantation Surgery (1) Preoperative preparation Fasting is allowed for 12 hours before surgery, but water intake is permitted; prepare analgesia: ibuprofen 0.2 mg / mL in drinking water. Anesthesia: Induction with isoflurane 3–4 vol% / maintenance with 1–2 vol% (oxygen flow 0.5–1 L / min). Prophylaxis with penicillin or cephalosporin.

[0106] Insulating pad, eye ointment; shave hair off the scalp and back of the neck muscles, and disinfect with iodine / alcohol in three steps.

[0107] (2) Positioning and Electrodes Fix the device to the stereotactic position, in the biting position. Expose the skull and locate the anterior fontanelle.

[0108] Common coordinates for screw EEG (bipolar or reference-active) measurements: Active electrodes: +1.5 mm AP, +1.5 mm mL (frontal lobe); Reference / Opposite Side: 2.0 mm AP, +2.0 mm mL (apical leaf); Ground line: nasal bone or occipital bone.

[0109] EMG: Remove 1–2 mm of insulation from two insulated wires, embed them into the bilateral neck muscles, and suture to fix them.

[0110] Screws are screwed into the hardened surface, soldered / pressed to the cap pins, and then encapsulated with light-cured resin and dental cement.

[0111] (3) Resuscitation and analgesia Subcutaneous fluid resuscitation: 0.5–1 mL of normal saline; local anesthesia with bupivacaine.

[0112] Individual cages with insulation and soft food; monitor weight and incision site. Record only if recovery lasts ≥7 days and weight loss is <10%.

[0113] Day 7 ~ 4|Restoration & Wiring Adjustment and Adaptation Wiring / rotary connector training: 30–60 minutes daily, gradually increasing to 2–3 hours, observing for wire tangling and limited mobility.

[0114] System calibration: channel impedance <100 kΩ; analog signal testing, 50 / 60 Hz noise check.

[0115] Single-cage environmental adaptation: The experimental cage was kept at the same temperature, humidity, and light as the formal record, with the same bedding and food / water supply.

[0116] Pre-baseline preparation: Confirm video synchronization, clock alignment, and animal ID and electrode mapping table.

[0117] Day 3 ~ 1 | Baseline continuous recording for 48–72 h Connect the data cable and continuously record EEG / EMG+ video for 48–72 hours.

[0118] Sampling: EEG 512–1000 Hz; High-pass 0.5 Hz, Low-pass 100 Hz; EMG High-pass 10 Hz.

[0119] Record 24-hour activity spectrum (distance traveled / rod count) and generate individual baseline sleep parameters: Total NREM / REM / wakefulness duration, number of bounces and average duration for each stage; NREM delta power (0.5–4 Hz) baseline value.

[0120] Removal criteria: mice with electrode detachment, EMG loss, or abnormal baseline sleep (e.g., total sleep <4 h / 12 ​​h photoperiod) were excluded and replaced.

[0121] Day 0 | Random Grouping Stratified randomization was performed using weight plus baseline NREM total duration to ensure balance between groups.

[0122] Blind coding (separation of operator and scorer).

[0123] Day 1–5 | CSD during the deprivation period (ZT0–ZT8) (4) Administration Intraperitoneal injection of ZT 0.5 (30 min before turning on the light): Study drug or carrier; injection dose 10 mL / kg (dissolved in physiological saline). Record batch number and dosage.

[0124] Observe for adverse reactions for 15 minutes.

[0125] (5) Sleep deprivation (ZT0–ZT8, 8 h / day × 5 d) Gentle intervention: When a slow, static EEG wave appears, gently touch the cage wall, gently blow on it, or introduce a novel object; avoid prolonged gripping.

[0126] Mechanical assistance: low-speed horizontal rotary bar / running wheel (1–2 rpm, 2 min on / 3 min off intermittently), alternating with manual intervention to reduce stress.

[0127] Record deprivation compliance (number of interventions per hour, animal activity score).

[0128] Parallel EEG / EMG+ behavior data are collected to monitor for the occurrence of "escape sleep".

[0129] (6) Post-deprivation continuous recording (ZT8–ZT24) No further intervention was performed, and records were continuously kept until the next day at ZT0; the main observations were rebound sleep and increased delta power.

[0130] Days 6–8 | Recovery and Rebound Discontinue deprivation and continue medication (until the end of Day 8, for a total of 3 days of "resumption of medication").

[0131] Continuous recording for 48–72 hours: Recording sleep duration 3. Experimental Results: The experimental results are attached. Figure 3 As shown in the figure, the results indicated that the sleep deprivation group (group ②) showed a significant reduction in sleep time and a significant increase in wakefulness, indicating that the model was successfully established and the mice were in a state of sleep disorder. The drug treatment groups (levotetrahydropalmatine citrate group (group ③) and melatonin group (group ④)) showed a significant recovery in sleep time and a decrease in wakefulness time, suggesting that the drugs have an improving effect on total sleep duration and sleep structure. The figure also shows that levotetrahydropalmatine citrate can have the same effect as melatonin in improving sleep disorders.

[0132] Experiment Example 7: Sedative Function Test of Different Salt Forms of Levotetrahydropalmatine This experimental example provides sedative function tests of different salt forms of levorotatory tetrahydropalmatine in Example 1 and Comparative Examples 1-7. The experimental procedure is as follows: 1. Experimental Design: The total distance of movement in mice after injection was used to measure the mice's motor response to the drug and the increase in addiction; a higher value indicated a stronger addiction. The behavior box (purchased from Shanghai Ruanxin Company) measured 44×44 cm, with a central area of ​​22×22 cm. Experimental groups included: ① Methamphetamine (METH) + saline group; ② Methamphetamine (METH) + L-tetrahydropalmatine citrate group; ③ Methamphetamine (METH) + L-tetrahydropalmatine hydrochloride group; ④ Methamphetamine (METH) + L-tetrahydropalmatine mesylate group; ⑤ Methamphetamine (METH) + L-tetrahydropalmatine malate group; ⑥ Methamphetamine (METH) + L-tetrahydropalmatine glucuronide group; 2. Experimental steps: (1) Overall schedule: Day 1 (Adaptation): Move the mice into the behavior room for 30 min to adapt → put them in the behavior box (open field) for 30 min to run (without injection) → return them to their cages.

[0133] Day 2: Adapt to the behavior room for 30 min → Place the mouse in the behavior box for 30 min (baseline) → Remove the mouse and inject it with methamphetamine 1 mg / kg (ip) → Immediately return it to the box and record for 60 min (post-injection).

[0134] Days 3-7: Repeat Day 2 steps daily, adjusting the methamphetamine (dissolved in saline) dose to 5 mg / kg (ip).

[0135] Day 8: Same as Day 2, but the methamphetamine dosage is adjusted to 1 mg / kg (ip).

[0136] Withdrawal period: Day 9 to Day 22: Intraperitoneal injection of 10 mg / kg of normal saline or different salt forms of levotetrahydropalmatine (dissolved in normal saline), and daily health monitoring.

[0137] Day 23 (Challenge): On day 26, inject methamphetamine 1 mg / kg (ip), following the same procedure as Day 2 (i.e., 30 min adaptation → 30 min baseline → injection → 60 min recording).

[0138] (2) Main observation indicators: Total distance after injection: total distance traveled within 60 minutes.

[0139] 3. Experimental Results: The experimental results are attached. Figure 4As shown, the results indicated that different salt forms of levotetrahydropalmatine exhibited significant differences in their effects on inhibiting spontaneous activity in mice. In the saline group (group ①), the average total movement distance of mice was approximately 1400-1500 cm, representing a normal activity level. In contrast, the movement distance in the levotetrahydropalmatine citrate group (group ②) was significantly reduced to only about 400-500 cm, indicating that it had the strongest sedative effect and significantly inhibited the movement activity of mice (P<0.01). Among the other salt forms, the movement distance in the levotetrahydropalmatine hydrochloride group (group ③) and the levotetrahydropalmatine mesylate group (group ④) was around 1000-1200 cm, with a significantly weaker sedative effect than the citrate group (group ②); the movement distance in the levotetrahydropalmatine malate group (group ⑤) and the levotetrahydropalmatine gluconate group (group ⑥) was close to that of the control group (approximately 1300-1500 cm), showing almost no significant inhibitory effect. Overall, the intraperitoneal injection group of levotetrahydropalmatine citrate showed the most significant sedative effect, with a total movement distance approximately one-third that of the saline control group. This indicates that the citrate salt form has higher bioavailability and sedative efficacy in terms of drug absorption and central nervous system effects. This result demonstrates that the choice of levotetrahydropalmatine salt form significantly affects its pharmacological activity, with citrate being one of the optimal formulations.

[0140] Experiment Example 8: Functional Trial of Different Salt Forms of Levotetrahydropalmatine for the Treatment of Sleep Disorders This experimental example provides a functional trial of different salt forms of levotetrahydropalmatine in treating sleep disorders in Example 1 and Comparative Examples 1-7. The experimental procedure is as follows: 1. Experimental Design: A sleep deprivation experiment was designed to record the NREM (non-rapid eye movement) and REM (rapid eye movement) sleep times of mice to measure sleep disturbance. Lower values ​​indicated a significant increase in wakefulness, suggesting the mice were in a state of sleep disorder. Experimental groups included: ① Blank behavior + saline (blank control group); ②Sleep deprivation + saline solution (sleep deprivation model group); ③ Sleep deprivation + L-tetrahydropalmatine citrate treatment group; ④ Sleep deprivation + melatonin (positive control group); ⑤ Sleep deprivation + levotetrahydropalmatine mesylate treatment group; ⑥ Sleep deprivation + L-tetrahydropalmatine glucuronide treatment group; ⑦ Sleep deprivation + L-tetrahydropalmatine acetate treatment group; ⑧ Sleep deprivation + L-tetrahydropalmatine malate treatment group; ⑨ Sleep deprivation + L-tetrahydropalmatine hydrochloride treatment group; ⑩ Sleep deprivation + L-tetrahydropalmatine lactate treatment group; Sleep deprivation + L-tetrahydropalmatine tartrate treatment group; 2. The experimental method is the same as that shown in Experiment Example 6; 3. Experimental Results: The experimental results are attached. Figure 5 As shown, the results indicated significant differences in the effectiveness of different salt forms of levotetrahydropalmatine in improving sleep disorders. The levotetrahydropalmatine citrate treatment group (group ③) and the melatonin treatment group (group ④) exhibited the best sleep-promoting effects, with average sleep durations of approximately 560 seconds and 580 seconds, respectively, significantly higher than the sleep deprivation model group (group ②, approximately 110 seconds) and other levotetrahydropalmatine salt groups. In contrast, the efficacy of other salt forms was in the following order: mesylate (group ⑤) > glucuronide (group ⑥) > acetate (group ⑦) > malate (group ⑧) > hydrochloride (group ⑨) > lactate (group ⑩) > tartrate (group ⑩). The study showed that citrate has unique advantages in promoting sleep recovery and prolonging sleep duration. Its effects are not only close to those of the classic sleep aid melatonin, but also exhibit higher safety and more stable efficacy. It significantly restored NREM sleep duration and sleep structure stability in a sleep deprivation model, demonstrating superior bioavailability and neuromodulation properties. Therefore, levotetrahydropalmatine citrate, as the optimal drug salt form of levotetrahydropalmatine, has outstanding application potential and clinical translational value in treating sleep disorders and improving sleep quality.

[0141] Experiment Example 9: Functional study of different routes of administration of levotetrahydropalmatine citrate on inhibiting drug addiction, sedation, and improving sleep disorders. This experimental example provides a functional trial of the nasal administration of levotetrahydropalmatine citrate in Example 1 on the inhibition of drug addiction, sedation, and improvement of sleep disorders.

[0142] Intranasal administration to mice: Administer 20 μL per mouse at a dose of 10 mg / kg, divided into both nostrils. Position the mouse supine with its head slightly tilted back (approximately 30°-45°). Using a 20 μL pipette, add the formulation in multiple drops into the nasal inlet, allowing it to enter the nasal cavity with spontaneous inhalation. Add 2-5 μL to each nostril at 20-60 seconds intervals, alternating between nostrils until administration is complete. Avoid forming a continuous liquid column during the dripping process to prevent aspiration; if a coughing reflex or abnormal breathing occurs, stop immediately and wait for recovery before continuing. After administration, maintain a supine position for 30-60 seconds and observe the general condition. The control group was given the same volume of the corresponding solvent.

[0143] The experimental procedure for inhibiting drug addiction is the same as in Experiment 4; the experimental procedure for the sedation function test is the same as in Experiment 5; and the experimental procedure for the sleep disorder improvement function test is the same as in Experiment 6.

[0144] The experimental results for inhibiting drug addiction are attached. Figure 6 As shown, in the Conditional Place Preference (CPP) test, both the intraperitoneal injection group and the nasal administration group showed negative scores (approximately -120 seconds) in the pre-test, indicating that no preference had been formed. After establishing the addiction model, the post-test scores of both groups rose to approximately 80–120 seconds, showing that drug-induced addictive preference was successfully formed. In the relapse phase, the CPP scores of both groups dropped significantly to below zero (approximately -50 to -120 seconds), indicating that both administration methods could effectively inhibit relapse preference. There were no significant differences (ns) between the groups in the three phases, indicating that nasal administration and intraperitoneal injection have the same effect in inhibiting addictive behavior.

[0145] The results of the sedation function test are attached. Figure 7 As shown in the attached figure, the experimental results of the functional test for improving sleep disorders are as follows. Figure 8 As shown. Figures 7-8 The results showed that nasal administration had the same sedative and sleep-promoting effects as intraperitoneal injection, with comparable overall efficacy. It also had the advantages of being non-invasive, having high compliance, and being easy to administer, showing great application potential.

[0146] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A levorotatory tetrahydropalmatine citrate, characterized in that, The structure of the levorotatory tetrahydropalmatine citrate is shown in formula (1): 。 2. The L-tetrahydropalmatine citrate according to claim 1, characterized in that, The preparation method of the L-tetrahydropalmatine citrate includes: reacting L-tetrahydropalmatine with citric acid in a solvent to form a salt, followed by evaporation and concentration, cooling and crystallization, filtration and washing and / or drying to obtain a solid product, and the obtained solid product is confirmed to have formed a salt by nuclear magnetic resonance.

3. The L-tetrahydropalmatine citrate according to claim 1 or 2, characterized in that, The molar ratio of the levorotatory tetrahydropalmatine to citric acid is 1:

1.

4. The L-tetrahydropalmatine citrate according to claim 1 or 2, characterized in that, The salt may be in solid form.

5. A pharmaceutical composition, characterized in that, The pharmaceutical composition comprises levotetrahydropalmatine citrate as described in any one of claims 1-4 and pharmaceutically acceptable excipients.

6. The pharmaceutical composition according to claim 5, characterized in that, The dosage form of the pharmaceutical composition includes at least one of oral formulations, nasal spray formulations, and injectable formulations; The oral formulations include conventional formulations, sustained-release formulations, and / or controlled-release formulations; The nasal spray formulation includes nasal aerosol.

7. The pharmaceutical composition according to claim 6, characterized in that, The oral formulation is an oral sustained-release formulation, which is a bilayer tablet comprising an immediate-release layer and a sustained-release layer, wherein the sustained-release layer comprises hydroxypropyl methylcellulose (HPMC).

8. The pharmaceutical composition according to claim 6, characterized in that, The oral formulation is an oral sustained-release formulation, which is a microcapsule. The microcapsule is prepared by an extrusion spheronization process, and the matrix of the microcapsule contains hydroxypropyl methylcellulose (HPMC) and / or microcrystalline cellulose (MCC).

9. The pharmaceutical composition according to claim 6, characterized in that, The oral formulation is an oral sustained-release formulation, and the oral sustained-release formulation is a coated formulation, wherein the coating component comprises a methacrylic acid copolymer material.

10. The pharmaceutical composition according to claim 9, characterized in that, The methacrylic acid copolymer material comprises Eudragit L100, Eudragit S100, Eudragit RS and / or Eudragit RL.

11. The use of the levotetrahydropalmatine citrate according to any one of claims 1-4 or the pharmaceutical composition according to any one of claims 5-10 in the preparation of a medicament, characterized in that, The drug has any of the following functions: (a) Sedation; (b) Analgesia; (c) Prevention and / or treatment of drug addiction; And / or, (d) prevent and / or treat sleep disorders.

12. The use according to claim 11, characterized in that, The sleep disorders include difficulty falling asleep, difficulty maintaining sleep, and / or abnormal sleep structure.

13. The use according to claim 11 or 12, characterized in that, The drug was able to promote NREM sleep recovery and / or REM sleep recovery in a sleep deprivation model, with statistical differences compared to the control group.

14. The use according to any one of claims 11-13, characterized in that, The dosage form of the drug includes at least one of oral formulations, nasal spray formulations, and injectable formulations.

15. A method for preparing the levorotatory tetrahydropalmatine citrate according to any one of claims 1-4, characterized in that, The method includes: reacting levorotatory tetrahydropalmatine with citric acid in a solvent to form a salt, followed by evaporation and concentration, cooling and crystallization, filtration and washing and / or drying to obtain a solid product, and using nuclear magnetic resonance to confirm the salt formation of the obtained solid product.

16. The method according to claim 15, characterized in that, The molar ratio of the levorotatory tetrahydropalmatine to citric acid is 1:

1.

17. The method according to claim 15 or 16, characterized in that, The solvent includes water.

18. The method according to any one of claims 15-17, characterized in that, The acid-base reaction temperature is 20-40℃.

19. The method according to any one of claims 15-18, characterized in that, The acid-base reaction is carried out under ultrasonic conditions; Optionally, the ultrasonic frequency is 10-16 kHz; Optionally, the ultrasound time is 5-15 minutes.

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