Pharmaceutical composition and its uses

Abstract

The present invention relates to (S)-3-aminomethyl-5-methylhexanoic acid or a pharmaceutically acceptable salt thereof, and a riluzole composition. The composition has broad applicability in the manufacture of agents for the treatment of neuropathic pain.

Description

Technology Field

[0001] The present application claims priority to Chinese patent application No. 202110742036.7, filed with the National Intellectual Property Administration of China on July 1, 2021, titled “Pharmaceutical composition and uses thereof,” the entire contents of which are incorporated herein by reference.

[0002] The present invention belongs to the field of pharmaceuticals and relates to a composition of (S)-3-aminomethyl-5-methylhexanoic acid and riluzole, and the use thereof in the manufacture of a drug for the treatment of neuropathic pain. Background Technology

[0003] Neuropathic pain (NP) is pain caused by damage or disease of the somatosensory system, classified into peripheral neuropathic pain and central neuropathic pain. Peripheral neuropathic pain is more common in clinical practice. European studies show that the prevalence of neuropathic pain in the general population reaches 8.0%. Neuropathic pain is not a single disease but a syndrome caused by various injuries and diseases, manifesting as a series of symptoms and signs that severely impact a patient's life. Postherpetic neuralgia and diabetic peripheral neuropathy are the two most common types of neuropathic pain. Chronic pain not only affects patients' sleep, work, and daily living abilities but also increases the incidence of emotional disorders such as depression and anxiety. Some studies show that the quality of life scores of patients with postherpetic neuralgia are only half that of the general population. There is currently a shortage of medications to treat neuropathic pain. Currently, calcium channel modulators, antidepressants, and local anesthetics are primarily used to treat neuropathic pain in clinical practice. However, due to the complexity of the etiology of neuropathic pain, the performance of existing treatments is unsatisfactory, and a significant number of patients fail to receive adequate pain relief.

[0004] In clinical practice, (S)-3-aminomethyl-5-methylhexanoate (pregabalin) can be used to treat peripheral neuropathic pain in adults, including diabetic peripheral neuropathy, fibromyalgia, and post-herpetic neuralgia, and is recommended as a first-line drug for the treatment of neuropathic pain by many international guidelines. The mechanism of action of pregabalin is considered to be the modulation of the voltage-gated calcium channel subunit α2δ and the reduction of the release of glutamate, norepinephrine, and substance P. Pregabalin can cause dizziness, drowsiness, and other side effects, which limits its application in clinical practice to some extent.

[0005] The structural formula of (S)-3-aminomethyl-5-methylhexanoic acid (pregabalin) is as follows:

[0006]

[0007] The molecular formula is C8H 17 It is NO2, and its molecular weight is 159.23.

[0008] Riluzole (chemical name: 2-amino-6-trifluoromethylbenzothiazole) is a drug developed by Sanofi for the treatment of amyotrophic lateral sclerosis (ALS). It was approved for marketing by the U.S. FDA and EMA in 1996 and plays a crucial role in extending survival, alleviating symptoms, and improving the quality of life for ALS patients. Its mechanism of action is thought to involve interfering with glutamate release, stabilizing the inactivated state of voltage-dependent sodium channels, and disrupting intracellular events following the binding of neurotransmitters to excitatory amino acid receptors. Riluzole possesses a broad range of pharmacological effects, including the modulation of glutamate and its transporters, as well as antidepressant, anxiolytic, antiepileptic, analgesic, and neuroprotective effects.

[0009] The structural formula of riluzole is as follows:

[0010]

[0011] The molecular formula is C8H5F3N2OS, and the molecular weight is 234.20.

[0012] It should be noted that even when two different drugs with identical pharmacokinetic effects are applied in combination, the efficacy of the combined application is highly complex and unpredictable, and phenomena of drug synergy, addition, and even antagonism may occur. Therefore, to those skilled in the art, it is difficult to simply conclude that riluzole can enhance the analgesic effect of pregabalin based on the fact of riluzole's analgesic effect, unless the necessary experimental data is obtained. Prior art literature

[65535] US2004 / 0054005AUS2010 / 0190751A Bifa FAN , Chinese Journal of Pain Medicine 2020, May 15, 2020, 26 (5), pages 321-328Miao et, al., Chinese Journal of Pain Medicine 2014,20 (4) means of solving the problem

[0013] The present invention provides a pharmaceutical composition comprising (S)-3-aminomethyl-5-methylhexanoic acid and riluzole, which, when used, can produce unexpected synergistic effects and enhance therapeutic effects against neuropathic pain.

[0014] The present invention provides the use of a pharmaceutical composition in the manufacture of a drug for the treatment of neuropathic pain. The pharmaceutical composition comprises (S)-3-aminomethyl-5-methylhexanoic acid or a pharmaceutically acceptable salt thereof and riluzole or a pharmaceutically acceptable salt thereof.

[0015] In the composition, the mass ratio of (S)-3-aminomethyl-5-methylhexanoic acid or a pharmaceutically acceptable salt thereof in the form of a free acid or base to riluzole or a pharmaceutically acceptable salt thereof is 50:1 to 1:20.

[0016] Preferably, the mass ratio of (S)-3-aminomethyl-5-methylhexanoic acid or a pharmaceutically acceptable salt thereof in the free acid or base form to riluzole or a pharmaceutically acceptable salt thereof is 20:1 to 1:10.

[0017] Preferably, the mass ratio of (S)-3-aminomethyl-5-methylhexanoic acid or a pharmaceutically acceptable salt thereof in the free acid or base form to riluzole or a pharmaceutically acceptable salt thereof is 20:1 to 1:4.

[0018] Preferably, the mass ratio of (S)-3-aminomethyl-5-methylhexanoic acid or a pharmaceutically acceptable salt thereof in the free acid or base form to riluzole or a pharmaceutically acceptable salt thereof is 10:1 to 1:4.

[0019] Preferably, the mass ratio of (S)-3-aminomethyl-5-methylhexanoic acid or a pharmaceutically acceptable salt thereof in the free acid or base form to riluzole or a pharmaceutically acceptable salt thereof is 6:1 to 1:4.

[0020] Preferably, the mass ratio of (S)-3-aminomethyl-5-methylhexanoic acid or a pharmaceutically acceptable salt thereof in the free acid or base form to riluzole or a pharmaceutically acceptable salt thereof is 3:1 to 1:2.

[0021] The pharmaceutical composition of the present invention can be used to manufacture a drug for treating neuropathic pain, wherein the neuropathic pain is preferably peripheral neuropathic pain.

[0022] More preferably, peripheral neuropathic pain is post-herpetic neuralgia and diabetic peripheral neuropathy. Effects of the invention

[0023] The results of animal pharmacokinetic studies show that the pharmaceutical composition comprising (S)-3-aminomethyl-5-methylhexanoic acid and riluzole provided by the present invention can exhibit synergistic effects and enhance therapeutic effects against peripheral neuropathic pain. Specific details for implementing the invention

[0024] Embodiments of the present invention will be described below clearly and completely, together with examples of the invention. Clearly, the described examples are only some embodiments, not all embodiments of the invention. Based on the examples of the invention, all other embodiments made by those skilled in the art without any inventive effort fall within the scope of protection of the present invention.

[0025] Example 1 Study 1 Pharmacokinetic Effects of a Composition of Pregabalin and Riluzole on Neuropathic Pain

[0026] 1 Materials and Methods

[0027] 1.1 Experimental Animals

[0028] Sprague-Dawley (SD) rat, male, SPF rating, body weight 150-200g

[0029] 1.2 Test Drugs

[0030]

[0031] 1.3 Experimental Method

[0032] 1.3.1 Construction of an Animal Model of Neuropathic Pain

[0033] In this experiment, a neuropathic pain model induced by isolated L5 spinal nerve ligation was adopted. Animals were anesthetized with 7% chloral hydrate (dosage: 420 mg / kg, intraperitoneal injection), and the rats' limbs were immobilized in a prone position. The rats' back hairs were trimmed, and they were placed under a dissecting microscope, wiped with alcohol, and disinfected. An incision approximately 2–3 cm in length was made on the right side of the dorsal spine to expose spinal nerves L4 and L5, and spinal nerve L5 was lightly ligated with a 6-0 braided line to avoid damage to adjacent spinal nerves. Double-layer sutures were applied to the dorsal incision site of the experimental animals, and after disinfection with iodophor, the animals were gently placed in a feeding cage, allowing free access for movement, eating, and drinking.

[0034] 1.3.2 Method for Determining Mechanical Pain Threshold

[0035] The mechanical withdrawal threshold (MWT) of all experimental animals was measured using a mechanical automatic stimulation needle. The experimental animals were placed in a transparent plexiglass box with iron gauze at the bottom and acclimatized for 30 minutes. Then, the vala of the hind legs of the experimental animals were stimulated with a needle stimulating at a constant speed, and the response threshold (MWT), which is the mechanical pain threshold of the animals, was recorded when the rat rapidly withdrew or shook its paw.

[0036] 1.3.3 Measurement and Calculation of Basic Pain Thresholds in Animals

[0037] The baseline mechanical pain threshold of each experimental animal was measured for 2 days after modeling, and the baseline mechanical pain threshold of the experimental animal was the average of the two values.

[0038] 1.4 Animal Grouping and Experimental Procedure

[0039] Experimental model animals were randomly divided into seven groups: a model control group, a pregabalin group (25 mg / kg), a pregabalin group (0.5 mg / kg), a riluzole group (10 mg / kg), a riluzole group (0.5 mg / kg), a group with a composition having a pregabalin-riluzole ratio of 50:1 (25 mg / kg pregabalin + 0.5 mg / kg riluzole), and a group with a composition having a pregabalin-riluzole ratio of 1:20 (0.5 mg / kg pregabalin + 10 mg / kg riluzole). Pregabalin and riluzole were administered by intraperitoneal injection, while the model control group was administered the corresponding blank solvent. Each group consisted of 11–12 animals.

[0040] The L5-SNL model was constructed by selecting SD rats of appropriate body weight, and measurements of mechanical pain thresholds after surgery were initiated at least 7 days after modeling. After surgery, animals with a significantly lower pain threshold in the right hind leg compared to the pain threshold in the contralateral hind leg were selected for all subsequent efficacy studies. The corresponding drug or solvent was administered to the experimental model animals, and the animals' mechanical pain thresholds were measured at 0.5 and 3 hours after administration.

[0041] 1.5 Synergy Analysis of the Composition

[0042] According to the formula q=E(a+b) / (Ea+Eb-Ea×Eb), Jin Zhengjun evaluated whether pregabalin and riluzole have a synergistic effect in the composition. In the formula, E(a+b) is the improvement rate of the composition of the two drugs, and Ea and Eb are the improvement rates of drug A (pregabalin) and drug B (riluzole) administered alone, respectively. E=(pain threshold after administration - model value) / (base value - model value). If the q value is in the range of 0.85–1.15, it means that the combination of the two drugs is simply additive; if the q value is greater than 1.15, it means that the combination of the two drugs has a synergistic effect; if the q value is less than 0.85, it means that the combination of the two drugs has an antagonistic effect.

[0043] 1.6 Data Statistics

[0044] Experimental data are expressed as mean ± standard error (Mean ± SEM). One-way ANOVA was used to analyze differences between groups, comparisons between groups were tested using the LSD method, and P < 0.05 was defined as a significant difference.

[0045] 2 results

[0046] The experimental results are shown in Table 1. Compared to the solvent control group, pregabalin (25 mg / kg), riluzole (10 mg / kg), composition (50:1), and composition (1:20) could all significantly increase the mechanical pain threshold of animals at 0.5 hours after administration (P=0.0463, P<0.0001, P=0.0458, P<0.0001). All of the above groups could also significantly increase the mechanical pain threshold of animals at 3 hours after administration (P<0.0001, P=0.0004, P<0.0001, P<0.0001). The calculation results of the synergy showed that the q values ​​of the composition (50:1) at 0.5 hours and 3 hours after administration were 1.073 and 0.919, respectively, and the q values ​​of the composition (1:20) at 0.5 hours and 3 hours after administration were 0.909 and 0.998, respectively.

[0047] Table 1 Mechanical pain threshold of animals in each group (Unit: g)

[0048]

[0049] Compared to the model control group, data were expressed as Mean±SEM, *P<0.05, ***P<0.001, ****P<0.0001.

[0050] Example 2 Study 2 Pharmacokinetic Effects of a Composition of Pregabalin and Riluzole on Neuropathic Pain

[0051] 1 Materials and Methods

[0052] 1.1 Experimental Animals

[0053] Sprague-Dawley (SD) rat, male, SPF rating, body weight 150-200g

[0054] 1.2 Test Drugs

[0055] Pregabalin and riluzole are the same as in Example 1.

[0056] 1.3 Experimental Method

[0057] The preparation of the neuropathic pain animal model, the method for measuring the mechanical pain threshold, and the measurement and calculation of the animal's baseline pain threshold are the same as in Example 1.

[0058] 1.4 Animal Grouping and Experimental Procedure

[0059] Experimental model animals were randomly divided into seven groups: a model control group, a pregabalin group (20 mg / kg), a pregabalin group (1 mg / kg), a riluzole group (10 mg / kg), a riluzole group (1 mg / kg), a group with a composition having a pregabalin-riluzole ratio of 20:1 (20 mg / kg pregabalin + 1 mg / kg riluzole), and a group with a composition having a pregabalin-riluzole ratio of 1:10 (1 mg / kg pregabalin + 10 mg / kg riluzole). Pregabalin and riluzole were administered by intraperitoneal injection, while the model control group was administered the corresponding blank solvent. Each group consisted of 12 animals.

[0060] The L5-SNL model was constructed by selecting SD rats of appropriate body weight, and measurements of mechanical pain thresholds after surgery were initiated at least 7 days after modeling. After surgery, animals with a significantly lower pain threshold in the right hind leg compared to the pain threshold in the contralateral hind leg were selected for all subsequent efficacy studies. The corresponding drug or solvent was administered to the experimental model animals, and the animals' mechanical pain thresholds were measured at 0.5 and 3 hours after administration.

[0061] 1.5 Synergy Analysis of the Composition

[0062] The synergy analysis of the composition is the same as in Example 1.

[0063] 1.6 Data Statistics

[0064] The data statistics are the same as in Example 1.

[0065] 2 results

[0066] The experimental results are shown in Table 2. Compared to the solvent control group, pregabalin (20 mg / kg), riluzole (10 mg / kg), composition (20:1), and composition (1:10) could all significantly increase the mechanical pain threshold of animals at 0.5 hours after administration (P=0.0278, P<0.0001, P=0.0483, P<0.0001). All of the above groups could also significantly increase the mechanical pain threshold of animals at 3 hours after administration (P<0.0001, P<0.0001, P<0.0001, P<0.0001, P<0.0001). The calculation results of the synergy showed that the q values ​​of composition (20:1) at 0.5 hours and 3 hours after administration were 1.216 and 1.181, respectively, and the q values ​​of composition (1:10) at 0.5 hours and 3 hours after administration were 1.206 and 1.213, respectively. This shows that both composition (20:1) and composition (1:10) have a synergistic effect at 0.5 hours and 3 hours after administration.

[0067] Table 2 Mechanical pain thresholds of animals in each group (Unit: g)

[0068]

[0069] Compared to the model control group, data were expressed as Mean±SEM, *P<0.05, ****P<0.0001.

[0070] Example 3 Study 3 Pharmacokinetic Effects of a Composition of Pregabalin and Riluzole on Neuropathic Pain

[0071] 1 Materials and Methods

[0072] 1.1 Experimental Animals

[0073] Sprague-Dawley (SD) rat, male, SPF rating, body weight 150-200g

[0074] 1.2 Test Drugs

[0075] Pregabalin and riluzole are the same as in Example 1.

[0076] 1.3 Experimental Method

[0077] The construction of the animal model of neuropathic pain, the method for measuring the mechanical pain threshold, and the measurement and calculation of the animal's baseline pain threshold are the same as in Example 1.

[0078] 1.4 Animal Grouping and Experimental Procedure

[0079] Experimental model animals were randomly divided into nine groups: a model control group, a pregabalin group (30 mg / kg), a pregabalin group (18 mg / kg), a pregabalin group (3 mg / kg), a riluzole group (12 mg / kg), a riluzole group (3 mg / kg), a group with a composition having a pregabalin-riluzole ratio of 10:1 (30 mg / kg pregabalin + 3 mg / kg riluzole), a group with a composition having a pregabalin-riluzole ratio of 1:4 (3 mg / kg pregabalin + 12 mg / kg riluzole), and a group with a composition having a pregabalin-riluzole ratio of 6:1 (18 mg / kg pregabalin + 3 mg / kg riluzole). Pregabalin and riluzole were administered by intraperitoneal injection, while the model control group was administered the corresponding blank solvent. Each group consisted of 10 to 12 animals.

[0080] The L5-SNL model was constructed by selecting SD rats of appropriate body weight, and measurements of mechanical pain thresholds after surgery were initiated at least 7 days after modeling. After surgery, animals with a significantly lower pain threshold in the right hind leg compared to the pain threshold in the contralateral hind leg were selected for all subsequent efficacy studies. The corresponding drug or solvent was administered to the experimental model animals, and the animals' mechanical pain thresholds were measured at 0.5 and 3 hours after administration.

[0081] 1.5 Synergy Analysis of the Composition

[0082] The synergy analysis of the composition is the same as in Example 1.

[0083] 1.6 Data Statistics

[0084] The data statistics are the same as in Example 1.

[0085] 2 results

[0086] The experimental results are shown in Table 3. Compared to the solvent control group, pregabalin (30 mg / kg), riluzole (12 mg / kg), composition (10:1), composition (1:4), and composition (6:1) can significantly increase the mechanical pain threshold of animals at 0.5 hours after administration (P=0.0111, P<0.0001, P<0.0001, P<0.0001, P=0.003). Pregabalin (30 mg / kg), pregabalin (18 mg / kg), riluzole (12 mg / kg), composition (10:1), composition (1:4) and composition (6:1) can all significantly increase the mechanical pain threshold of animals at 3 hours after administration (P<0.0001, P<0.0001, P<0.0001, P<0.0001, P<0.0001, P<0.0001, P<0.0001). The calculation results of the synergy showed that the q values ​​of composition (10:1) at 0.5 hours and 3 hours after administration were 1.273 and 1.182, respectively, the q values ​​of composition (1:4) at 0.5 hours and 3 hours after administration were 1.210 and 1.211, respectively, and the q values ​​of composition (6:1) at 0.5 hours and 3 hours after administration were 1.222 and 1.269, respectively. This shows that composition (10:1), composition (1:4), and composition (6:1) all have a synergistic effect at 0.5 hours and 3 hours after administration.

[0087] Table 3 Mechanical pain thresholds of animals in each group (Unit: g)

[0088]

[0089] Compared to the model control group, data were expressed as Mean±SEM, *P<0.05, **P<0.01, ****P<0.0001.

[0090] Example 4 Study 4 Pharmacokinetic Effects of a Composition of Pregabalin and Riluzole on Neuropathic Pain

[0091] 1 Materials and Methods

[0092] 1.1 Experimental Animals

[0093] Sprague-Dawley (SD) rat, male, SPF rating, body weight 150-200g

[0094] 1.2 Test Drugs

[0095] Pregabalin and riluzole are the same as in Example 1.

[0096] 1.3 Experimental Method

[0097] The construction of the animal model of neuropathic pain, the method for measuring the mechanical pain threshold, and the measurement and calculation of the animal's baseline pain threshold are the same as in Example 1.

[0098] 1.4 Animal Grouping and Experimental Procedure

[0099] Experimental model animals were randomly divided into 11 groups, namely, a model control group, a pregabalin group (18 mg / kg), a pregabalin group (9 mg / kg), a pregabalin group (3 mg / kg), a riluzole group (12 mg / kg), a riluzole group (6 mg / kg), a riluzole group (3 mg / kg), a group with a composition having a ratio of pregabalin to riluzole of 6:1 (18 mg / kg pregabalin + 3 mg / kg riluzole), a group with a composition having a ratio of pregabalin to riluzole of 3:1 (9 mg / kg pregabalin + 3 mg / kg riluzole), a group with a composition having a ratio of pregabalin to riluzole of 1:4 (3 mg / kg pregabalin + 12 mg / kg riluzole), and a group with a composition having a ratio of pregabalin to riluzole of 1:2 (3 mg / kg pregabalin + 6 mg / kg riluzole). Pregabalin and riluzole were administered by intraperitoneal injection, and the model control group was administered the corresponding blank solvent. Each group consists of 10 animals.

[0100] The L5-SNL model was constructed by selecting SD rats of appropriate body weight, and measurements of mechanical pain thresholds after surgery were initiated at least 7 days after modeling. After surgery, animals with a significantly lower pain threshold in the right hind leg compared to the pain threshold in the contralateral hind leg were selected for all subsequent efficacy studies. The corresponding drug or solvent was administered to the experimental model animals, and the animals' mechanical pain thresholds were measured at 0.5 and 3 hours after administration.

[0101] 1.5 Synergy Analysis of the Composition

[0102] The synergy analysis of the composition is the same as in Example 1.

[0103] 1.6 Data Statistics

[0104] The data statistics are the same as in Example 1.

[0105] 2 results

[0106] The experimental results are shown in Table 4. Compared to the solvent control group, riluzole (12 mg / kg), riluzole (6 mg / kg), composition (6:1), composition (3:1), composition (1:4), and composition (1:2) can significantly increase the mechanical pain threshold of animals at 0.5 hours after administration (P<0.0001, P=0.0031, P=0.0033, P=0.0123, P<0.0001, P<0.0001). Pregabalin (18 mg / kg), pregabalin (9 mg / kg), riluzole (12 mg / kg), riluzole (6 mg / kg), composition (6:1), composition (3:1), composition (1:4) and composition (1:2) can all significantly increase the mechanical pain threshold of animals at 3 hours after administration (P<0.0001, P<0.0001, P<0.0001, P=0.0427, P<0.0001, P<0.0001, P<0.0001, P<0.0001). The calculation results of the synergy showed that at 0.5 hours and 3 hours after administration, the q values ​​of composition (6:1) were 1.250 and 1.248, respectively; at 0.5 hours and 3 hours after administration, the q values ​​of composition (3:1) were 1.389 and 1.391, respectively; at 0.5 hours and 3 hours after administration, the q values ​​of composition (1:4) were 1.235 and 1.294, respectively; and at 0.5 hours and 3 hours after administration, the q values ​​of composition (1:2) were 1.320 and 1.384, respectively. This shows that composition (6:1), composition (3:1), composition (1:4), and composition (1:2) all have a synergistic effect at 0.5 hours and 3 hours after administration.

[0107] Table 4 Mechanical pain thresholds of animals in each group (Unit: g)

[0108]

[0109] Compared to the model control group, data were expressed as Mean±SEM, *P<0.05, **P<0.01, ****P<0.0001.

[0110] Example 5 Study 5 Pharmacokinetic Effects of a Composition of Pregabalin and Riluzole on Neuropathic Pain

[0111] 1 Materials and Methods

[0112] 1.1 Experimental Animals

[0113] Sprague-Dawley (SD) rat, male, SPF rating, body weight 150-200g

[0114] 1.2 Test Drugs

[0115] Pregabalin and riluzole are the same as in Example 1.

[0116] 1.3 Experimental Method

[0117] The construction of the animal model of neuropathic pain, the method for measuring the mechanical pain threshold, and the measurement and calculation of the animal's baseline pain threshold are the same as in Example 1.

[0118] 1.4 Animal Grouping and Experimental Procedure

[0119] Experimental model animals were randomly divided into nine groups: a model control group, a pregabalin group (9 mg / kg), a pregabalin group (6 mg / kg), a pregabalin group (3 mg / kg), a riluzole group (6 mg / kg), a riluzole group (3 mg / kg), a group with a composition having a pregabalin-riluzole ratio of 3:1 (9 mg / kg pregabalin + 3 mg / kg riluzole), a group with a composition having a pregabalin-riluzole ratio of 1:2 (3 mg / kg pregabalin + 6 mg / kg riluzole), and a group with a composition having a pregabalin-riluzole ratio of 1:1 (6 mg / kg pregabalin + 6 mg / kg riluzole). Pregabalin and riluzole were administered by intraperitoneal injection, while the model control group was administered the corresponding blank solvent. Each group consisted of 10 to 11 animals.

[0120] The L5-SNL model was constructed by selecting SD rats of appropriate body weight, and measurements of mechanical pain thresholds after surgery were initiated at least 7 days after modeling. After surgery, animals with a significantly lower pain threshold in the right hind leg compared to the pain threshold in the contralateral hind leg were selected for all subsequent efficacy studies. The corresponding drug or solvent was administered to the experimental model animals, and the animals' mechanical pain thresholds were measured at 0.5 and 3 hours after administration.

[0121] 1.5 Synergy Analysis of the Composition

[0122] The synergy analysis of the composition is the same as in Example 1.

[0123] 1.6 Data Statistics

[0124] The data statistics are the same as in Example 1.

[0125] 2 results

[0126] The experimental results are shown in Table 5. Compared to the solvent control group, riluzole (6 mg / kg), composition (3:1), composition (1:2), and composition (1:1) can significantly increase the mechanical pain threshold of animals at 0.5 hours after administration (P=0.0011, P=0.0006, P<0.0001, P<0.0001). Pregabalin (9 mg / kg), pregabalin (6 mg / kg), riluzole (6 mg / kg), composition (3:1), composition (1:2), and composition (1:1) can all significantly increase the mechanical pain threshold of animals at 3 hours after administration (P<0.0001, P=0.0015, P=0.0315, P<0.0001, P<0.0001, P<0.0001). The calculation results of the synergy showed that the q values ​​of composition (3:1) at 0.5 hours and 3 hours after administration were 1.362 and 1.384, respectively; the q values ​​of composition (1:2) at 0.5 hours and 3 hours after administration were 1.330 and 1.361, respectively; and the q values ​​of composition (1:1) at 0.5 hours and 3 hours after administration were 1.453 and 1.501, respectively. This shows that composition (3:1), composition (1:2), and composition (1:1) all have a synergistic effect at 0.5 hours and 3 hours after administration.

[0127] Table 5 Mechanical pain thresholds of animals in each group (Unit: g)

[0128]

[0129] Compared to the model control group, data were expressed as Mean±SEM, *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001.

[0130] Example 6 Study 6 Pharmacokinetic Effects of a Composition of Pregabalin and Riluzole on Neuropathic Pain

[0131] 1 Materials and Methods

[0132] 1.1 Experimental Animals

[0133] Sprague-Dawley (SD) rat, male, SPF rating, body weight 150-200g

[0134] 1.2 Test Drugs

[0135] Pregabalin and riluzole are the same as in Example 1.

[0136] 1.3 Experimental Method

[0137] The construction of the animal model of neuropathic pain, the method for measuring the mechanical pain threshold, and the measurement and calculation of the animal's baseline pain threshold are the same as in Example 1.

[0138] 1.4 Animal Grouping and Experimental Procedure

[0139] Experimental model animals were randomly divided into 11 groups, namely, a model control group, a pregabalin group (30 mg / kg), a pregabalin group (20 mg / kg), a pregabalin group (6 mg / kg), a riluzole group (10 mg / kg), a riluzole group (7.5 mg / kg), a riluzole group (6 mg / kg), a group with a composition having a pregabalin-riluzole ratio of 1:1 (6 mg / kg pregabalin + 6 mg / kg riluzole), a group with a composition having a pregabalin-riluzole ratio of 2:1 (20 mg / kg pregabalin + 10 mg / kg riluzole), a group with a composition having a pregabalin-riluzole ratio of 3:1 (30 mg / kg pregabalin + 10 mg / kg riluzole), and a group with a pregabalin-riluzole ratio of 4:1 (30 mg / kg pregabalin + 7.5 mg / kg riluzole). They were divided into groups with compositions having a ratio of pregabalin to riluzole of 5:1 (30 mg / kg pregabalin + 6 mg / kg riluzole). Pregabalin and riluzole were administered by intraperitoneal injection, and the model control group was administered the corresponding blank solvent. Each group consists of 8 to 10 animals.

[0140] The L5-SNL model was constructed by selecting SD rats of appropriate body weight, and measurements of mechanical pain thresholds after surgery were initiated at least 7 days after modeling. After surgery, animals with a significantly lower pain threshold in the right hind leg compared to the pain threshold in the contralateral hind leg were selected for all subsequent efficacy studies. The corresponding drug or solvent was administered to the experimental model animals, and the animals' mechanical pain thresholds were measured at 0.5, 3, 6, and 8 hours after administration.

[0141] 1.5 Synergy Analysis of the Composition

[0142] According to Jin Zhengjun's formula q=E(a+b) / (Ea+Eb-Ea×Eb), pregabalin and riluzole in the composition are E max A synergistic effect was evaluated at time point (3 hours). In the equation, E(a+b) is the improvement rate of the combination of the two drugs, and Ea and Eb are the improvement rates of drug A (pregabalin) and drug B (riluzole) administered alone, respectively. E = (pain threshold after administration - model value) / (base value - model value). If the q value is in the range of 0.85–1.15, it means that the combination of the two drugs is simply additive; if the q value is greater than 1.15, it means that the combination of the two drugs has a synergistic effect; if the q value is less than 0.85, it means that the combination of the two drugs has an antagonistic effect.

[0143] CompuSyn software was used to analyze whether there was a synergistic effect on the overall efficacy of pregabalin and riluzole in the composition within 0–8 hours after administration. The formula for calculating the improvement rate of the drug group is (AUC 0-8시간 - Model value * 8 hours) / (default value * 8-hour model value *It was 8 hours. The combination index (CI) of each composition group was calculated using software. If CI < 1, it means that the combination of the two drugs has a synergistic effect, if CI = 1, it means that the combination of the two drugs is simply additive, and if CI > 1, it means that the combination of the two drugs has an antagonistic effect.

[0144] 1.6 Data Statistics

[0145] The data statistics are the same as in Example 1.

[0146] 2 results

[0147] The experimental results are shown in Table 6. Compared to the solvent control group, all of the following were able to significantly increase the mechanical pain threshold of animals at 0.5 hours after administration: pregabalin (30 mg / kg), riluzole (10 mg / kg), riluzole (7.5 mg / kg), riluzole (6 mg / kg), compositions with a ratio of pregabalin to riluzole of 1:1, compositions with a ratio of pregabalin to riluzole of 2:1, compositions with a ratio of pregabalin to riluzole of 3:1, compositions with a ratio of pregabalin to riluzole of 4:1, and compositions with a ratio of pregabalin to riluzole of 5:1 (P=0.018, P<0.0001, P<0.0001, P<0.0001, P<0.0001, P<0.0001, P<0.0001, P<0.0001, P<0.0001). Pregabalin (30 mg / kg), pregabalin (20 mg / kg), pregabalin (6 mg / kg), riluzole (10 mg / kg), composition (1:1), composition (2:1), composition (3:1), composition (4:1) and composition (5:1) can all significantly increase the mechanical pain threshold of animals at 3 hours after administration (P<0.0001, P<0.0001, P=0.0008, P=0.023, P<0.0001, P<0.0001, P<0.0001, P<0.0001, P<0.0001). Pregabalin (30 mg / kg), pregabalin (20 mg / kg), pregabalin (6 mg / kg), composition (1:1), composition (2:1), composition (3:1), composition (4:1) and composition (5:1) can all significantly increase the mechanical pain threshold of animals at 6 hours after administration (P<0.0001, P<0.0001, P=0.0007, P<0.0001, P<0.0001, P<0.0001, P<0.0001, P<0.0001). Pregabalin (30 mg / kg), pregabalin (20 mg / kg), pregabalin (6 mg / kg), composition (1:1), composition (2:1), composition (3:1), composition (4:1) and composition (5:1) can all significantly increase the mechanical pain threshold of animals at 8 hours after administration (P<0.0001, P<0.0001, P=0.0008, P<0.0001, P<0.0001, P<0.0001, P<0.0001, P<0.0001, P<0.0001). Synergy was calculated according to the Jin Zhengjun formula, and the results showed that at 3 hours after administration, the q value of composition (1:1) was 1.296, at 3 hours after administration, the q value of composition (2:1) was 1.258, at 3 hours after administration, the q value of composition (3:1) was 1.266, at 3 hours after administration, the q value of composition (4:1) was 1.319, and at 3 hours after administration, the q value of composition (5:1) was 1.264. This showed that at 3 hours after administration, composition (1:1), composition (2:1), composition (3:1), composition (4:1), and composition (5:1) all had a synergistic effect. CompuSyn software analysis showed that the CI value of the AUC of composition (1:1) after administration was 0.634, the CI value of the AUC of composition (2:1) after administration was 0.364, the CI value of the AUC of composition (3:1) after administration was 0.349, the CI value of the AUC of composition (4:1) after administration was 0.328, and the CI value of the AUC of composition (5:1) after administration was 0.349. This showed that composition (1:1), composition (2:1), composition (3:1), composition (4:1), and composition (5:1) all had a synergistic effect within 0-8 hours after administration.

[0148] Table 6 Mechanical pain thresholds of animals in each group (Unit: g)

[0149]

[0150] Compared to the model control group, data were expressed as Mean±SEM, *P<0.05, **P<0.01, **P<0.001, ****P<0.0001.

Claims

Claim 1 A pharmaceutical composition for treating neuropathic pain comprising (S)-3-aminomethyl-5-methylhexanoic acid or a pharmaceutically acceptable salt thereof and riluzole or a pharmaceutically acceptable salt thereof as active ingredients, wherein the mass ratio of (S)-3-aminomethyl-5-methylhexanoic acid or a pharmaceutically acceptable salt thereof and riluzole or a pharmaceutically acceptable salt thereof in free acid or base form is 20:1 to 1:

10. Claim 2 A pharmaceutical composition according to claim 1, wherein the mass ratio of (S)-3-aminomethyl-5-methylhexanoic acid or a pharmaceutically acceptable salt thereof and riluzole or a pharmaceutically acceptable salt thereof in the form of a free acid or base is 20:1 to 1:

4. Claim 3 A pharmaceutical composition according to claim 1, wherein the mass ratio of (S)-3-aminomethyl-5-methylhexanoic acid or a pharmaceutically acceptable salt thereof and riluzole or a pharmaceutically acceptable salt thereof in the form of a free acid or base is 10:1 to 1:

4. Claim 4 A pharmaceutical composition according to claim 1, wherein the mass ratio of (S)-3-aminomethyl-5-methylhexanoic acid or a pharmaceutically acceptable salt thereof and riluzole or a pharmaceutically acceptable salt thereof in the form of a free acid or base is 6:1 to 1:

4. Claim 5 A pharmaceutical composition according to claim 1, wherein the mass ratio of (S)-3-aminomethyl-5-methylhexanoic acid or a pharmaceutically acceptable salt thereof and riluzole or a pharmaceutically acceptable salt thereof in the form of a free acid or base is 3:1 to 1:

2. Claim 6 A pharmaceutical composition in which the neuropathic pain in claim 1 is peripheral neuropathic pain. Claim 7 A pharmaceutical composition in which, in paragraph 6, peripheral neuropathic pain is post-herpetic neuralgia. Claim 8 In paragraph 6, a pharmaceutical composition in which peripheral neuropathic pain is diabetic peripheral neuropathy. Claim 9 delete Claim 10 delete Claim 11 delete

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