RU2680244C1 - Combination of flupirtine and cyclobenzaprine for treatment of pain syndromes - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: invention relates to the field of medicine, pharmacology, namely to a new pharmaceutical combination of flupirtine and cyclobenzaprine, or their pharmaceutically acceptable salts.EFFECT: invention is intended for the treatment of pain syndromes, including pain associated with static and functional diseases of the spine; pain syndrome after injuries and surgical interventions; pain associated with skeletal muscle spasticity; pain associated with a malignant process; headache; dysmenorrhea and algodismenorrhea.9 cl, 8 tbl, 8 ex

Description

The invention relates to medicine, pharmacology, in particular to a combination of flupirtine and cyclobenzaprine or their pharmaceutically acceptable salts for the treatment of various types of pain. This combination is used to treat pain syndromes, particularly preferably pain syndromes, accompanied by severe spasticity of the muscles, in particular:

- pain associated with static and functional diseases of the spine (cervical and lumbar syndromes);

- pain after injuries and surgical interventions (for example, due to a hernia of the intervertebral disc or osteoarthritis of the hip joint);

- spasticity of skeletal muscles in neurological diseases, for example, with multiple sclerosis, chronic myelopathy, neurodegenerative diseases;

- with a headache;

- for pain associated with a malignant process;

- with dysmenorrhea, algomenorrhea.

Pain is one of the most common complaints that doctors of various specialties deal with in everyday practice. The prevalence of pain in primary care varies from 11 to 40% [Gureje O., Simon G. E., Van Korff M. “A cross-national study of the course of persistent pain in primary care” // Pain. 2001. Vol. 92. P. 195-200]. According to WHO, in developed countries, the pain in terms of its spread is quite comparable to a pandemic.

To achieve success in treatment, it is important to distinguish between acute and chronic pain. Acute pain is inextricably linked to the damage that caused it and is usually a symptom of a disease. It usually disappears when the damage is repaired and / or the healing period expires. Chronic pain continues for a long time even after the cause of acute pain has been eliminated, and often acquires the status of an independent disease. The International Association for the Study of Pain defines it as "pain that continues beyond the normal healing period." The main difference between chronic and acute pain is not a temporary factor, but qualitatively different neurophysiological, biochemical, psychological and clinical relationships [Korzhavina VB, Danilov AB “New opportunities and prospects for the treatment of pain syndromes” // breast cancer. 2010. S. 31].

The final perception of pain is the result of the interaction of nociceptive and antinociceptive systems. The formation of pain in a person is mediated by the structures of the nociceptive system, which carries out the perception, conduct and processing of information about various stimuli. The downward inhibitory cerebrospinal control of pain impulses is a function of the antinociceptive system. Under physiological conditions, the antinociceptive system provides optimal modulation of the perception of pain stimuli, protecting against pain and maintaining pain thresholds at a certain level. However, long-term damaging effects often lead to sensitization of the pain system (stable long-term depolarization of neurons), which gives rise to its pathophysiological changes [“Pain syndromes in neurological practice” // Ed. Corr. RAMS A.M. Wayne. M .: MEDpress-inform, 2001].

Short-term pain stimuli cause short activation of nociceptive neurons of the posterior horns of the spinal cord due to the effect of glutamate secreted by A-delta and C-afferents on AMPA receptors. This mechanism underlies normal nociceptive stimuli.

In the case of repeated and longer stimulation of C-fibers, there is not only an increase in the release of glutamate, but also secretion of neuropeptides (substance P, calcitonin, gene-linked peptide, neurokinin A), which both independently excite nociceptive neurons and potentiate the exciting effect of glutamate on NMDA receptors. The latter contain Na ⁺ / Ca ²⁺ - ion channels, which have the highest throughput for calcium ions in comparison with other ion channels associated with receptors for other excitatory amino acids. Normally, these channels are inactive because they are blocked by magnesium ions. The allocation of primary afferents by the central terminals along with the glutamate of substance P activates type I neurokinin receptors, resulting in the development of slow postsynaptic action potentials (lasting tens of seconds), temporary summation and disappearance of the magnesium block of NMDA receptors. As a result of activation of NMDA receptors through the opened voltage-gated channels, calcium begins to actively enter the cell, increasing the excitability of the postsynaptic membrane with the development of persistent depolarization. In addition, the entry of calcium ions into the cell leads to the activation of nitric oxide synthetase, protein kinase C, phosphorylation and persistent activation of NMDA receptors. All these processes underlie the development of the so-called “wind up” phenomenon, which is characterized by a sharp increase in the frequency of action potentials on the membrane of sensitive neurons of the posterior horn of the spinal cord.

Due to an increase in the excitability of sensitive neurons of the posterior horns of the spinal cord associated with the innervation zone of the damaged nerve, sensitization of nearby intact neurons occurs with the expansion of the receptive zone. Therefore, irritation of intact sensitive fibers that innervate healthy tissues surrounding the damage zone causes activation of secondary sensitized neurons, which is manifested by pain - secondary hyperalgesia.

Sensitization of neurons of the posterior horns leads to a decrease in the pain threshold and the development of allodynia - the appearance of pain for irritation, which is normally not accompanied by them (for example, tactile). Changes in the excitability of the central parts of the nociceptive system associated with the development of secondary hyperalgesia and allodynia are described by the term “central sensitization”.

Considering the peculiarities of the pathogenesis of the development of both neuropathic and nociceptive pains, the treatment of NMDA receptors of the membranes of the neurons of the horn appears to be a promising treatment method. Blockade of NMDA receptors can be caused both by directly affecting the glutamate-binding regions of the receptor (competitive antagonists - ketamine, dextromethorphan), and, less often, due to communication with its other regions (non-competitive, indirect antagonism).

Thus, several stages are distinguished in the mechanisms of sensitization of nociceptive neurons: activation of AMPA receptors (α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid) in response to short-term stimulation of pain afferents, then excitation of NMDA receptors (N-methyl-D-aspartate) glutamate when repeated or prolonged damaging effect is applied. This leads to the removal of magnesium ions blocking the NMDA receptor channels, resulting in intracellular entry of calcium ions. Under conditions of increased intake of calcium into neurons, the expression of c – fos, c – jun, jun B early response genes occurs, which, by activating effector genes, change the cellular phenotype and form long-term neuronal hyper-excitability. Through such mechanisms, central sensitization can exist even after the initial initiating factors are eliminated [Kukushkin M.L., Khitrov N.K. “General pathology of pain." - M .: Medicine, 2004. - 144 s].

Therefore, timely and adequate treatment of acute pain syndrome with the aim of preventing the chronicity of the pathological condition is fundamentally important.

Among the drugs used in clinical practice for the treatment of acute pain, the most widely used are analgesics, non-steroidal anti-inflammatory drugs and muscle relaxants. It is at this stage with the help of traditional non-steroidal anti-inflammatory drugs (NSAIDs) that it is possible to act on peripheral components that contribute to the formation of pain - eliminating inflammation, edema, and suppressing neurochemical stimulators of pain receptors.

In the case of chronic pain, when the central pathophysiological mechanisms of pain are turned on, it is necessary to use drugs that affect the formation of central sensitization:

- the use of anticonvulsants (carbamazepine, lamotrigine, valproate), which inhibit the stimulation of nerve impulses by blocking the voltage-gated sodium and calcium channels of the peripheral nerves;

- the use of reuptake blockers of norepinephrine and serotonin, which increase the concentration of these neurotransmitters in the nuclei of the reticular formation of the brain stem, from which the descending inhibitory pathways affecting the interneurons of the horn come from (fluoxetine, amitriptyline, sertraline, duloxetine, etc.);

- the use of NMDA receptor antagonists that erase pain memory (ketamine, dextromethorphan);

- electrical stimulation and other methods of physical stimulation (physiotherapy, acupuncture, percutaneous electroneurostimulation, massage, etc.) that cause inhibition of nociceptive neurons of the horn by activating enkephalinergic neurons [Barinov AN “Comprehensive treatment of pain” // breast cancer, 2007, volume 15, No. 4, p. 215–220].

A fundamentally new class of drugs for the treatment of pain syndromes is selective activators of neuronal potassium channels - SNEPCO (Selective Neuronal Potassium Channel Opener), which affect the sensitization of neurons of the horn by stabilizing the membrane resting potential.

Flupirtine was synthesized in the 70s [von Bebenburg W., Thiel K., Engel J., Sheldrick W.S. “Synthese und Molekulstruktur des konstitutionell neuartigen analgetikum Flupirtin” // Chem Z, 1981, 105: 77-81]. In 1986, he was approved for treatment in the Federal Republic of Germany. Since then, it began to be actively used in clinical practice, and the new information obtained about its therapeutic effect and special properties contributed to its wider use.

Flupirtine (catadolone) is the first representative of a new class of drugs that belong to the group of selective activators of neuronal potassium channels. This is a drug with a central mechanism of action, but unlike narcotic analgesics, it does not cause dependence or addiction. It is important to emphasize that in addition to the analgesic effect, it has muscle relaxant and neuroprotective properties.

[2-amino-6 - [[(4-fluorophenyl) methyl] amino] -3-pyridinyl] carbamic
acid ethyl ester (flupirtine)

Flupirtine is a central non-opioid analgesic, selective activator of neuronal K ⁺ channels. Due to indirect antagonism with respect to NMDA receptors, activating the downstream mechanisms of pain modulation and GABAergic processes, it has analgesic, muscle relaxant and neuroprotective effects. The analgesic effect of flupirtine is due to the selective activation of neuronal potassium channels, while further influx of calcium ions into the cell stops, magnesium ions again block the NMDA receptor, which leads to stabilization of the membrane potential and a decrease in the excitability of neurons. At therapeutic concentrations, it does not bind to alpha ₁ and alpha ₂ adrenergic receptors, 5-HT ₁ and 5-HT ₂ serotonin, dopamine, benzodiazepine, opioid, and central cholinergic receptors. In therapeutic doses, it activates potential-independent K + channels, which leads to stabilization of the membrane potential of the nerve cell. In this case, the inhibition of the activity of NMDA receptors (N-methyl-D-aspartate receptors) and, as a result, blockage of neuronal Ca ²⁺ channels, a decrease in the intracellular current of Ca ²⁺ , and inhibition of neuronal excitation in response to nociceptive stimuli (analgesia) occur. As a result of these processes, the formation of nociceptive (pain) sensitivity and the phenomenon of "wind up"("inflation" - an increase in the neuronal response to repeated pain stimuli) are constrained, which prevents the intensification of pain, its transition to a chronic form, and leads to chronic pain syndrome to reduce its intensity. It was also established that the modulating effect of flupirtine on the perception (perception) of pain is carried out through the descending noradrenergic system.

The muscle relaxant effect is associated with blocking the transmission of excitation to motor neurons and intermediate neurons, leading to a weakening of muscle tension. This flupirtine effect is important for patients with chronic diseases accompanied by painful muscle cramps. The drug acts almost exclusively on those muscles of the body that are under additional stress.

The neuroprotective properties of the drug determine the protection of nerve structures from the toxic effects of high concentrations of intracellular Ca ²⁺ , which is associated with its ability to block neuronal Ca ²⁺ channels and reduce intracellular Ca ²⁺ current. Flupirtine has better tolerance than tramadol and pentazocine [Devulder J. “Flupirtine in pain management: pharmacological properties and clinical use” // CNS Drugs. 2010, 24 (10): 867-81; Knost B., Flor H., Braun C. and Birbaumer N. “Cerebral processing of words and the development of chronic pain” // Psychophysiology. 1997. Vol. 34. P. 474-481].

Flupirtine is poorly soluble in water, therefore it is used in the form of salts: maleate, gluconate, as well as salts of other carboxylic acids and salts of sulfonic acids and their polymorphs, which are included in pharmaceutical compositions containing flupirtine salts and polymorphs. for the treatment of disorders of the nervous system, pain, musculoskeletal system, as well as other diseases and conditions [US2012028930, 02.02.2012].

The use of flupirtine, as well as its maleate salt in chronic musculoskeletal, rheumatic and oncological pain syndromes, showed its high efficiency and good tolerability. The elimination of pain improves the emotional state of patients and normalizes sleep, this may explain the slight drowsiness that occurs on the first day of the drug. The ease of prescribing the drug (1 capsule 100 mg 3 times a day) and its cancellation (you can stop taking it at the same time, without fear of the development of the withdrawal syndrome) make it convenient and easy to use for a doctor of any specialty. The duration of the drug is: 10 days - for the relief of acute pain syndromes and prevent their chronicity and 1-2 months - for the treatment of chronic pain. During treatment, there is no need to increase the dose of the drug, on the contrary - there is an increase in analgesic activity. Flupirtine is deprived of negative psychological or motor functions and does not affect reproductive function [Singal, R., Parveen G., Nidhi J., Samita G. // "Role of Flupirtine in the Treatment of Pain - Chemistry and its Effects". Mædica - a Journal of Clinical Medicine. 2012, 7 (2): 163-166]. This allows the wide use of flupirtine and flupirtine maleate in clinical practice for the treatment of chronic pain syndromes of various etiologies [Harish S., Bhuvana K., Bengalorkar G.M., Kumar T. // "Flupirtine: Clinical pharmacology". Journal of anaesthesiology, clinical pharmacology. 2012, 28 (2): 172-7] and the prevention of chronic pain syndromes.

Flupirtine was also noted for its neuroprotective properties and has been investigated for possible use in Creutzfeldt-Jakob disease, Alzheimer's disease and multiple sclerosis. [Klawe C., Maschke M. "Flupirtine: pharmacology and clinical applications of a nonopioid analgesic and potentially neuroprotective compound" // Expert opinion on pharmacotherapy. 2009, 10 (9): 1495-1500]. It has also been proposed as a possible treatment for Batten’s disease [Dhar S., Bitting R.L., Rylova S.N., et al. "Flupirtine blocks apoptosis in batten patient lymphoblasts and in human postmitotic CLN3- and CLN2-deficient neurons." // Ann. Neurol. 2002, 51 (4): 448-466] and is undergoing clinical trials as a drug for treating multiple sclerosis and fibromyalgia [Pipex Pharmaceuticals (PPXP) Oral Flupirtine Receives IND With FDA for Phase II Clinical Trial for Fibromyalgia 4/21/2008].

The largest study to evaluate the analgesic effect, normalization of muscle tone, and flupirtine tolerance in the treatment of acute and chronic pain associated with muscle tension is an open multicenter study in Germany [Mueller-Schwefe G. “Flupirtine in Acute and Chronic Pain Associated with Muscle Tenseness. Results of a Postmarketing Surveillance Study ”// Fortschr. Med. 2003. Vol. 121. P. 3-10].

The study involved 7806 patients (men - 43%, women - 57%) suffering from various types of musculoskeletal pain in the back, neck, tension headache (GBN) and myofascial pain syndrome of a different location. The average age of the patients was 52.3 ± 15.3 years. Mostly chronic forms of pain were noted (44.8%). In 29.4% of cases, the disease was acute, in 25.8% - subacute. 64.5% of patients previously received analgesic drug therapy, in 28.8% of cases, analgesic therapy was combined with muscle relaxants. Only 1.8% of patients received muscle relaxant monotherapy. Prior to the study of drug treatment, 23.5% of patients did not receive treatment, of which only 5% had chronic forms of the disease.

We assessed the intensity of pain, the degree of muscle tension, pain with pressure and the limitations of everyday activity on a 5-point scale with the following degrees of violation of the described parameters: 0 - no disturbance, 1 - mild, 2 - moderate, 3 - severe, 4 - very severe disturbance . In addition, the doctors and patients participating in the study evaluated the efficacy and tolerance of flupirtine also on a 5-point scale (excellent / good / satisfactory / unsatisfactory / non-evaluable).

Monitoring the dynamics of the process was carried out for 4 weeks, while making notes about the first visit to the doctor and two dispensary observations - one and four weeks after the start of therapy. Initial and maintenance doses for Katadolone treatment were predominantly 200–300 mg per day (2-3 capsules). Doses exceeding 300 mg per day were used only in 19.4% of patients at the beginning of treatment and in 4.5% of patients as a maintenance dose.

Already in the first week of treatment of acute and chronic forms, a significant decrease (p <0.01) in the intensity of pain was noted with a continuing decrease in pain during further treatment. The improvement was more pronounced and clinically developed faster in cases of acute illness compared with patients with chronic pain (p <0.01)

Pressure pain during flupirtine therapy also decreased statistically significantly (p <0.01) and significantly from a clinical point of view.

Clinically significant and statistically significant (p <0.01) efficacy of flupirtine in relation to normalization of tone was detected for all pathologies studied. Positive dynamics was statistically significant for all forms of pain, especially rapid and distinct development of the effect was noted for acute forms of the disease.

To assess the quality of life, the limitations of daily activities and sleep disorders associated with pain and muscle tension were investigated. After flupirtine therapy, a clinically significant and statistically significant (p <0.01) improvement was observed in both parameters. Side effects have been reported in approximately 70 patients (0.9%). All observed side effects were previously known. Most often noted weakness (16 cases) and dizziness (9 cases). No dangerous side effects have been reported. This indicates the good tolerance of Catadolone (flupirtine) in the treatment of musculoskeletal pain.

Thus, the results of this study confirm the efficacy of flupirtine in relieving pain and normalizing muscle tone in the treatment of acute and chronic pain associated with muscle tension, and demonstrate good tolerability of flupirtine, which justifies the usefulness of flupirtine in the treatment of these disorders.

Pain in patients with osteoporosis is becoming an increasingly significant problem in modern gerontology [Ferrell B.A. “Pain management in elderly people” // J. Am. Geriatr. Soc. 1991. Vol. 39 (1). P. 64-73; Lynch D. “Geriatric Pain” // Curr. Rev. Pain. 1999. Vol. 3 (5). P. 388-399]. The main indication for the administration of analgesics by elderly patients is musculoskeletal pain mainly against the background of diseases such as rheumatoid arthritis, osteoarthritis and osteoporosis [Sorkin B.A., Rudy T.E. et al. “Chronic pain in old and young patients: differences appear less important than similarities” // J. Gerontol. 1990. Vol. 45 (2). P. 64-68]. It was established that the target results of pain therapy in a significant part of this group of patients are not achieved. This state of the problem may be due to the lack of awareness of the attending physicians about the current recommendations for analgesic therapy, as well as to doubts when prescribing appropriate analgesics to elderly patients, which in one way or another may affect the general condition of patients due to concomitant pathology

Often in elderly patients, pain syndromes form against the background of osteoporosis. An individual selection of systematic analgesic therapy for patients with osteoporosis is also very important because it prevents further bone demineralization, which inevitably occurs when the patient is immobilized. The pain syndrome in osteoporosis is almost always accompanied by muscle pain, therefore, analgesics with a muscle relaxant component, to which flupirtine belongs, are of particular interest.

For a large cohort of patients with pain on the background of osteoporosis, in conditions as close as possible to everyday medical practice, the efficacy and safety of daily use of flupirtine was proved regardless of age, location of pain, its strength and time of treatment initiation. It has been shown that the inclusion of flupirtine in the treatment regimen of chronic pain syndrome in osteoporosis is a rational solution for the local physician and may be applicable to a wide range of patients [Ringe JD, Miethe D., Pittrow D., Wegscheider K. “Analgesic efficacy of flupirtine in primary care of patients with osteoporosis related pain. A multivariate analysis ”// Arzneimittelforschung. 2003. Vol. 53 (7). P. 496-502].

In the source [Riethmüller-Winzen H. “Flupirtine in the treatment of postoperative pain” // Postgrad. Med. J. 1987. Vol. 63, Suppl. 3. P. 61-65] published a review of several double-blind randomized controlled trials with parallel groups, in which the safety and efficacy of flupirtine in postoperative pain was shown. The studies involved patients after thyroidectomy, tonsillectomy, laparotomy, hysterectomy, episiotomy, transurethral resection of the prostate, surgery for fractures.

In the studies reviewed, flupirtine showed good analgesic activity in situations with pain intensity of up to 4 out of 5 points. The drug tolerance was also good. Flupirtine showed no less analgesic activity than the known analgesics with which it was compared (paracetamol, metamizole, naproxen, codeine, pentazocine).

In the study [Mazzarella B., Ceccarelli M.G. & Bianchi F. “Analgesic activity of flupirtine maleate” // J. Int. Med. Res. 1988. Vol. 16. P. 338-348] flupirtine was compared with ketoprofen in the treatment of pain after episiotomy. The study was carried out by a double blind method with the conduct of parallel groups. Randomization was performed according to a balanced scheme. The authors concluded that flupirtine can be used on a par with well-known analgesics such as ketoprofen to treat pain after an episiotomy.

A controlled study with parallel groups for evaluating the analgesic activity of flupirtine compared to sodium diclofenac is described in the source [Mastronardi P., D'Onofrio M., Scanni E. et al. “Analgesic activity of flupirtine maleate: a controlled double-blind study with diclofenac sodium in orthopedics” // J. Int. Med. Res. 1988. Vol. 16 (5). P. 338-348]. The study involved 40 patients over 18 years old who were hospitalized for planned orthopedic surgery. The study was randomized using a computer random number generator. The study participants began to receive 100 mg of flupirtine or 50 mg of diclofenac sodium in the immediate postoperative period. It was concluded that the use of 100 mg of flupirtine is at least as effective as the use of 50 mg of diclofenac sodium to anesthetize patients after orthopedic surgery. A comprehensive assessment of the effectiveness of the drug, including a verbal assessment of pain by patients and a generalized assessment at the end of therapy, showed the adequacy of the achieved analgesia. The onset rate and duration of the flupirtine effect at a dose of 100 mg are statistically significantly higher than those for diclofenac sodium at a dose of 50 mg.

In pain syndromes, spasm in the muscles develops with two fundamentally different groups of diseases:

neurological diseases;

degenerative-dystrophic lesions of the joints and spine - osteochondrosis, spondylosis, spondylarthrosis, arthrosis of the joints of the extremities.

Two of the above pathologies are fundamentally different from each other. In diseases of the nervous system, a painful muscle spasm or tonic tension of muscle fibers develops when pain irritation is applied.

The characteristic of pain with painful muscle spasm: the pain is local in nature within the spasmodic muscle; provoked by irritation of the affected muscle; when probing muscle fibers, intense pain is determined; muscle tone is increased.

The main features of pain in degenerative-dystrophic lesions or myofascial pain syndrome: reflected or regional pain, which is always far from the spasmodic muscle; on palpation of a painful muscle, the pain is significantly increased; sharp diffuse muscle spasm with inclusions of the compaction sites, which play the role of the trigger, when you click on these areas, very intense pain develops in the muscle and at a distance.

Spasmodic and painful muscles are a non-specific symptom. Before proceeding with its treatment, it is necessary to exclude a serious pathology, for example, metastases, fractures, infections, which at first can only manifest this symptomatology.

There are muscle relaxants that act exclusively on the first or second group of diseases, for example, only on diseases of the nervous system, or systemic diseases of the connective tissue.

Cyclobenzaprine is a centrally acting muscle relaxant that is effective against both problems.

3- (5H-dibenzo [a, d] cyclohepten-5-ylidene) -N, N-dimethyl-1-propanamine hydrochloride

(cyclobenzaprine)

Cyclobenzaprine (Flexeril, proheptatriene, MK-130) belongs to the group of peripheral muscle relaxants. This group of drugs reduces stress caused by muscle spasms. Muscle relaxants act directly on those parts of the brain that regulate muscle tone. Muscle relaxants along with non-steroidal anti-inflammatory drugs, analgesics and antispasmodics are included in the complex therapy of the acute and chronic stages of osteochondrosis and other diseases of the musculoskeletal system [Goodnick PJ, Sandoval R. “Psychotropic treatment of chronic fatigue and related disorders” // J Clin Psychiatry 1993, 54: 13-20]. Flexeril-branded cyclobenzaprine, among others, is a muscle relaxant used to relieve skeletal muscle spasm and related pain in acute musculoskeletal disorders [Chou R., Peterson K., Helfand M. "Comparative efficacy and safety of skeletal muscle relaxants for spasticity and musculoskeletal conditions: a systematic review. " Journal of Pain Symptom Management. 2004, 28 (2): 140-175].

After a traumatic lesion, painful muscle cramps can occur, aimed at stabilizing the affected part of the body and preventing further damage. Cyclobenzaprine is used to treat such muscle cramps associated with acute, painful musculoskeletal conditions. It reduces pain in the first two weeks [van Tulder M.W., Touray T., Furlan A.D., Solway S., Bouter L.M. "Muscle relaxants for non-specific low back pain" // Cochrane Database of Systematic Reviews. 2003, 2 (1-2): 91-9]. Moreover, in the source [Browning R., Jackson J.L., O’Malley P.G. "Cyclobenzaprine and back pain: a meta-analysis." Archives of Internal Medicine. 2001, 161 (13): 1613-1620] it is said that the drug is effective only in the first days, but after two weeks its benefits have not been proven and therapy cannot be continued for a long time. This can lead to a state of increased muscle tone, which leads to difficulty and stiffness of the muscles and interferes with normal movements, gait and speech due to neurological conditions such as cerebral palsy. [Ashby P., Burke D., Rao S. "Assessment of cyclobenzaprine in the treatment of spasticity" // J Neurol Neurosurg Psychiatry. 1972, 35 (5): 599-605.]

Cyclobenzaprine has also been shown to be effective in treating the symptoms of fibromyalgia to reduce pain, but without altering fatigue or tender points. [Tofferi J.K., Jackson J.L., O'Malley P.G. "Treatment of fibromyalgia with cyclobenzaprine: A meta-analysis" // Arthritis Rheum. 2004, 51 (1): 9-13] It can also be used along with other tetanus treatments [Smith, Blaine T. (2014). “Pharmacology for Nurses." Jones & Bartlett Publishers. p. 122].

The sedative effect of cyclobenzaprine was also noted, which is probably due to its antagonistic effect on histamine, serotonin and muscarinic receptors, and a side effect such as agitation, which is observed especially often in older people, is also noted. In general, it is recommended to avoid the use of cyclobenzaprine in the elderly because of the possibility of more serious side effects ["High risk medications". National Committee for Quality Assurance. February 1, 2010], characteristic of any tricyclic antidepressants [Chabria, Shiven B. "Rhabdomyolysis: a manifestation of cyclobenzaprine toxicity" // Journal of Occupational Medicine and Toxicology. 2006, 1 (1): 16]. Unlike dantrolene, cyclobenzaprine cannot be used to treat muscle spasm secondary to a disease of the brain or spinal cord.

Like other tricyclic antidepressants, cyclobenzaprine exhibits anticholinergic activity, while it does not directly affect the neuromuscular node or muscle, but relieves muscle cramps through a central action, possibly at the level of the brain stem. Cyclobenzaprine binds to the serotonin receptor and is considered an antagonist of 5-HT ₂ receptors, which reduces muscle tone, decreasing the activity of descending serotonergic neurons [US9636408, 05/02/2017].

Cyclobenzaprine is most easily administered as a salt with a non-toxic acid. Such salts are prepared by methods known in the art. One such method is used to prepare the preferred cyclobenzaprine hydrochloride salt and involves precipitating the salt from a solution of cyclobenzaprine in chloroform by saturating the solution with dry hydrogen chloride and cooling the solution. Other pharmaceutically acceptable salts of cyclobenzaprine are also known [US3409640, 11/05/1968].

“Pharmaceutically acceptable salt” means the relatively non-toxic organic and inorganic salts of the acids and bases of the present invention. These salts can be obtained in situ during the synthesis, isolation or purification of the compounds or prepared specially. In particular, base salts can be prepared on the basis of the purified free base of the claimed compound and a suitable organic or inorganic acid. Examples of salts thus obtained are hydrochlorides, hydrobromides, sulfates, bisulfates, phosphates, nitrates, acetates, oxalates, valeriates, oleates, palmitates, stearates, laurates, borates, benzoates, lactates, tosylates, citrates, maleates, fumarates, succinates, tartrates mesylates, malonates, salicylates, propionates, ethanesulfonates, benzenesulfonates, sulfamates and the like (A detailed description of the properties of such salts is given in Berge SM, et al. “Pharmaceutical Salts” // J. Pharm. Sci. 1977, 66: 1-19) . Salts of the claimed acids can also be specially prepared by reacting the purified acid with a suitable base, and metal and amine salts can be synthesized. Metal salts include sodium, potassium, calcium, barium, zinc, magnesium, lithium and aluminum salts, the most desirable of which are sodium and potassium salts. Suitable inorganic bases from which metal salts can be obtained are hydroxide, carbonate, sodium bicarbonate and hydride, potassium hydroxide and bicarbonate, potash, lithium hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide. As organic bases from which salts of the claimed acids can be obtained, amines and amino acids are selected that are sufficiently basic to form a stable salt and are suitable for medical use (in particular, they should have low toxicity). Such amines include ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, benzylamine, dibenzylamine, dicyclohexylamine, piperazine, ethylpiperidine, tris (hydroxymethyl) aminomethane and the like. In addition, tetraalkylammonium hydroxides, for example, such as choline, tetramethylammonium, tetraethylammonium and the like, can be used for salt formation. As amino acids, the main amino acids can be used - lysine, ornithine and arginine.

The prevalence of pain syndromes, associated spastic phenomena in muscles caused by neuralgic or infectious diseases, degenerative-dystrophic lesions of the joints and spine objectively worsens the quality of life of people, therefore, the search for new drugs and combinations that can effectively fight acute pain syndromes and at the same time do not have known side effects is an important and relevant task.

The authors of the present invention unexpectedly found that the problem is solved by a unique new combination for the treatment of acute pain syndromes, which allows you to keep the sedative and muscle relaxant effects for 6 to 8 hours due to cyclobenzaprine and analgesia for 24 hours due to flupirtine.

The strength of the analgesic effect of the new combination corresponds to the strength of opioid analgesics (for example, tramadol), but there are no adverse effects associated with the use of opioids.

As mentioned above, the use of analgesics in combination with muscle relaxants is known in the art, but it is not known to use a combination of flupirtine and cyclobenzaprine, or their pharmaceutically acceptable salts, for the treatment of pain syndromes, including those accompanied by severe muscle spasticity. Moreover, the combined use of an analgesic and muscle relaxant is not always obvious in view of their various side effects and limitations when interacting with other drugs, so their selection is an important technical and experimental task.

So frequent side effects of flupirtine are dizziness, heartburn, nausea, vomiting, constipation or diarrhea, flatulence, abdominal pain, dry oral mucosa, anorexia, depression, sleep disturbances, sweating, anxiety, nervousness, tremor, headache, diarrhea. Rarer side effects of flupirtine are confusion, visual impairment, and allergic reactions (hyperthermia, urticaria, and pruritus).

Flupirtine enhances the action of ethanol, sedatives, and muscle relaxants.

Due to the fact that flupirtine binds to blood plasma proteins, the possibility of displacing it with other drugs that are simultaneously taken should be taken into account (it is shown that warfarin and diazepam are displaced by flupirtine from the protein, which, when taken at the same time, can increase their effect ) With the simultaneous administration of flupirtine and coumarin derivatives, it is recommended to regularly monitor the Quick index (prothrombin index).

With the simultaneous use of flupirtine and drugs that are also metabolized in the liver, regular monitoring of the activity of liver enzymes is required.

The combined use of flupirtine and drugs containing paracetamol and carbamazepine (a tricyclic analog of cyclobenzaprine) should be avoided.

Cyclobenzaprine can provoke the following undesirable side effects: dyspepsia, apathy, insomnia; impaired coordination of movements; confusion of consciousness; unstable emotional state; partial or complete loss of performance.

Due to the slowed metabolism and metabolic features in the elderly, the drug is more slowly excreted from the body. Therefore, its appointment in medium therapeutic dosages can lead to toxic effects and poisoning.

The toxicity of cyclobenzaprine is explained by its ability to cause central and peripheral cholinergic blockade (antimuscarinic effect). In animal experiments, it blocks muscarinic receptors, increases the activity of externally administered norepinephrine, stimulating the release of endogenous catecholamines from presynaptic neurons (and at high doses, probably weakening their reverse absorption), and acts as an antihistamine. In laboratory animals, the intravenous administration of cyclobenzaprine suppresses rigidity in case of intercollic and anemic decerebration (gamma and alpha rigidity, respectively) and weakens it in case of spinal cord ischemia.

Based on structural similarities with tricyclic antidepressants, cyclobenzaprine may have life-threatening interactions with MAO inhibitors, and may also enhance the effects of alcohol, barbiturates, and other central nervous system depressants. May increase the risk of seizures in patients taking tramadol; it may also block the antihypertensive effect of guanethidine and similarly acting compounds.

There have been cases of serotonin syndrome during the combined use of cyclobenzaprine and other drugs, such as selective serotonin reuptake inhibitors, selective serotonin and norepinephrine reuptake inhibitors, tricyclic antidepressants, tramadol, bupropion, trimeperidine, verapamil inhibitor.

In this regard, there is an opinion that drugs based on cyclobenzaprine can be used only in combination with other medicines. By itself, it can be harmful to health, so the medication should not be taken on its own.

The authors of the present invention found that the use of a combination of flupirtine and cyclobenzaprine, or their pharmaceutically acceptable salts, can reduce the side effects associated with the monotherapy of each drug, which allows to expand its use, and to achieve an unexpected synergistic effect in the treatment of pain syndromes, including those associated pronounced muscle spasticity.

The task is carried out, and the technical result is achieved by obtaining a combination for the treatment of pain syndromes containing in effective amounts flupirtine and cyclobenzaprine, or their pharmaceutically acceptable salts.

According to preferred embodiments, the specified technical result is also achieved by the fact that:

- the introduction of a combination that is administered orally;

 - flupirtine and cyclobenzaprine are present as sustained release tablets;

- active substances are contained in preferred daily dosages:

flupirtine  - 25 - 600 mg / day; cyclobenzaprine  - 1.25 - 30 mg / day;

- active substances are contained in preferred weight ratios:

flupirtine: cyclobenzaprine from 1: 1.2 to 480: 1.

The task is also carried out, and the technical result is achieved by obtaining a pharmaceutical composition for the treatment of pain syndromes, containing in effective amounts a combination of flupirtine and cyclobenzaprine, or their pharmaceutically acceptable salts, as well as at least one excipient and / or at least one pharmaceutically acceptable carrier .

According to preferred embodiments, the specified technical result is also achieved by the fact that:

- the introduction of the composition is carried out orally;

- active substances are contained in preferred daily dosages:

flupirtine  - from 25 to 600 mg / day; cyclobenzaprine  - from 1.25 to 30 mg / day;

- active substances are contained in preferred weight ratios:

flupirtine: cyclobenzaprine from 1: 1.2 to 480: 1.

 The task is also carried out, and the technical result is achieved by obtaining a kit for the treatment of pain syndromes, which contains instructions for use and a pharmaceutical composition containing in an effective amount of cyclobenzaprine or its pharmaceutically acceptable salt, at least one excipient and / or at least one pharmaceutically an acceptable carrier and a pharmaceutical composition comprising, in an effective amount, flupirtine or a pharmaceutically acceptable salt thereof and at least one excipient and / or at least one pharmaceutically acceptable carrier.

According to preferred embodiments, the specified technical result is also achieved by the fact that:

The task is also carried out, and the technical result is achieved by using a combination of either a pharmaceutical composition or a kit according to the present invention for the treatment of a pain syndrome selected from the group including:

pain syndrome associated with static and functional diseases of the spine;

pain after injuries and surgical interventions;

pain syndrome associated with spasticity of skeletal muscles;

pain associated with a malignant process;

headache; dysmenorrhea and algomenorrhea.

According to preferred embodiments, the specified technical result is also achieved by the fact that:

- the introduction of a combination, composition or kit is administered orally;

- active substances are administered in preferred daily dosages:

flupirtine  - from 25 to 600 mg / day; cyclobenzaprine  - from 1.25 to 30 mg / day.

"Pharmaceutical composition" means a composition comprising a new combination of substances of the present invention, or their pharmaceutically acceptable salts, and at least one of the components selected from the group consisting of pharmaceutically acceptable and pharmacologically compatible excipients, solvents, diluents, carriers, auxiliary, distribution agents, delivery vehicles, such as preservatives, stabilizers, fillers, dispersing agents, moisturizers, emulsifiers, suspending agents, thickening agents, sweeteners, perfumes, flavors, antibacterial agents, fungicides, lubricants, prolonged delivery regulators, the choice and ratio of which depends on the nature of the active substances, route of administration and dosage. Examples of suspending agents are ethoxylated isostearyl alcohol, polyoxyethylene, sorbitol and sorbitol ether, microcrystalline cellulose, aluminum metahydroxide, bentonite, agar-agar and tragacanth, as well as mixtures of these substances. Protection against the action of microorganisms can be achieved using a variety of antibacterial and antifungal agents, for example, such as parabens, chlorobutanol, sorbic acid and the like. The composition may also include isotonic agents, for example, sugars, sodium chloride and the like. The prolonged action of the composition can be achieved using agents that slow down the absorption of the active principle, for example, such as aluminum monostearate and gelatin. Examples of suitable carriers, solvents, diluents and delivery vehicles are water, ethanol, polyalcohols, and also mixtures thereof, vegetable oils (such as olive oil) and injectable organic esters (such as ethyl oleate). Examples of excipients are lactose, milk sugar, sodium citrate, calcium carbonate, calcium phosphate and the like. Examples of dispersing and distributing agents are starch, alginic acid and its salts, silicates. Examples of lubricants are magnesium stearate, sodium lauryl sulfate, talc, and high molecular weight polyethylene glycol. The pharmaceutical composition for oral, sublingual, transdermal, intramuscular, intravenous, subcutaneous, local or rectal administration of the active principle, alone or in combination with another active principle, can be administered to animals and humans in a standard administration form, in the form of a mixture with traditional pharmaceutical carriers. Suitable unit dosage forms include oral forms such as tablets, gelatine capsules, pills, powders, granules, chewing gums and oral solutions or suspensions, sublingual and buccal administration forms, aerosols, implants, local, transdermal, subcutaneous, intramuscular, intravenous, intranasal or intraocular administration forms and rectal administration forms.

Pharmaceutical compositions may include pharmaceutically acceptable excipients. By pharmaceutically acceptable excipients are meant diluents, excipients and / or carriers used in the pharmaceutical field. The pharmaceutical composition along with the active substances of the present invention, or their pharmaceutically acceptable salts, may include other active substances, including those having activity, provided that they do not cause undesirable effects.

If necessary, the use of the pharmaceutical composition of the present invention in clinical practice, it can be mixed with traditional pharmaceutical carriers.

Carriers used in the pharmaceutical compositions of the present invention are carriers that are used in the pharmaceutical field to produce common forms, including oral agents using binders, lubricants, disintegrants, solvents, diluents, stabilizers, suspending agents, flavoring agents ; antiseptic agents, solubilizers, stabilizers are used in injection forms; in local forms, bases, diluents, lubricants, antiseptic agents are used.

Medicines and pharmaceutical compositions may be administered orally or parenterally (e.g., intravenously, subcutaneously, intraperitoneally or topically). The clinical dosage of an agent containing the new combination of flupirtine and cyclobenzaprine of the present invention in patients can be adjusted depending on the therapeutic efficacy and bioavailability of the active ingredients in the body, their metabolic rate and excretion from the body, as well as on the age, sex and stage of the patient’s disease. however, the daily dose in adults is usually 10 to 1000 mg of flupirtine, preferably 25 to 600 mg of flupirtine, and 0.5 to 50 mg of cyclobenzaprine, preferably 1.25 to 30 mg of cyclobene APRIN. Therefore, when preparing the drug of the present invention in the form of dosage units from the pharmaceutical composition, the aforementioned effective dosage must be taken into account, with each dosage unit containing 5–500 mg of flupirtine and 0.25–50 mg of cyclobenzaprine. In accordance with the instructions of a doctor or pharmacist, these drugs can be taken several times during certain periods of time (preferably from one to six times).

The following examples illustrate but do not limit the invention.

Example 1. Evaluation of the effectiveness of a combination of flupirtine and cyclobenzaprine for the treatment of pain associated with static and functional diseases of the spine.

To evaluate the effectiveness of drugs for the treatment of pain associated with static and functional diseases of the spine (for example, cervical and lumbar syndromes), a model of transection of two of the three branches of the sciatic nerve in rats was chosen [Bennett G.J., Xie Y.K. “A peripheral mononeuropathy in rat that produces disorders of pain sensation like those seen in man” // Pain. 1988, 33: 87-107. Decosterd I., Woolf C.J. “Spared nerve injury: an animal model of persistent peripheral neuropathic pain” // Pain. 2000, 87: 149-158. Kim S.H., Chung J.M. “An experimental-model for peripheral neuropathy produced by segmental spinal nerve ligation in the rat” // Pain. 1992, 50: 355-363].

Rats: 55 adult male Sprague-Dawley rats having a body weight of 250-330 grams were used in the experiments. Rats were kept in five individuals in temperature-controlled boxes (with an average temperature of 21 ° C) at a 12-hour cycle of day and night and with sufficient water and food.

Model description: 10 days after the operation of nerve transection in rats, during which a functional or static disease of the spine was simulated against a background of a pain syndrome, the efficacy of taking test drugs for the treatment of this pain syndrome was studied in rats.

Surgery. Rats were anesthetized with isoflurane (Sigma, USA). The skin on the lateral surface of the rat thigh was cut and then an incision was made on the biceps of the thigh to allow access to the sciatic nerve and its three terminal branches: calf, common peroneal and tibial nerves. Only the tibial and common peroneal nerves were subjected to axotomy and ligation, while the gastrocnemius nerve remained intact. These nerves were ligated with 5.0 silk threads and cut distally from the ligation site, leaving a 2 ± 4 mm nerve stump. Muscles and skin were sutured separately.

Formation of study groups: rats were randomly assigned to 11 groups of equal composition (5 animals in each), differing in the type of drug administered and its dosage.

Injectable drugs and doses: the study was conducted for 3 drugs (flupirtine, cyclobenzaprine and diclofenac), which were administered orally 10 days after surgery and 30 minutes before the conduct of behavioral tests in the indicated doses and combinations: flupirtine, 25 mg / day (group No. 1 ); flupirtine, 300 mg / day (group No. 2); flupirtine, 600 mg / day (group No. 3); cyclobenzaprine, 1.25 mg / day (group No. 4); cyclobenzaprine, 15 mg / day (group No. 5); cyclobenzaprine, 30 mg / day (group No. 6); flupirtine, 25 mg / day + cyclobenzaprine, 1.25 mg / day (group No. 7); flupirtine, 300 mg / day + cyclobenzaprine, 15 mg / day (group No. 8); flupirtine, 600 mg / day + cyclobenzaprine, 30 mg / day (group No. 9); and diclofenac, 50 mg / day (group No. 10). The control was a group of rats receiving only the vehicle (placebo group). All doses are calculated per person.

Behavioral tests

The severity of pain in different groups of animals was evaluated using two tests, fixing the development of cold or mechanical allodynia. Animals were tested 10 days after surgery, 30 minutes after the administration of the studied drugs.

Mechanical allodynia. The animals were placed in an acrylic chamber (15x15x15 cm) raised above the ground with a wire mesh at the bottom. Before testing, animals were left in the chamber for 5-10 minutes to adapt. Further, the plantar surface of the animal's paws was stimulated by calibrated von Frey filaments (or filaments) (BIOSEB, USA). The filaments were a set of 10 standard plastic threads, increasing in diameter. The stiffness of the threads, expressed as the minimum force required to bend the hair, increased with this calibration logarithmically with absolute values from 0.6 grams to 26 grams. In each rat, the sensitivity threshold was determined in turn on each paw in three repetitions (a total of 6 applications with an interval of 10 seconds for each filament; the interval between sequential application of different filaments was 2 minutes). The tip of the thread touched the middle of the plantar surface of the paw with the force necessary to bend the hair, and held the hair in this position for 6-8 seconds. A positive response was recorded if the animal abruptly pulled back its paw while touching. The sensitivity threshold was determined by the minimum pressure that causes the reflex reaction of the paw withdrawal (4 times out of 6 applications).

Cold allodynia. To evaluate cold allodynia, a special hot / cold plate test chamber (Ugo Basile, Italy) was used in this study. The test was carried out in a chamber with acrylic walls 30 cm high on a 30x30 cm metal plate cooled to 0 ° C. Healthy animals are able to withstand this temperature for a long time, resting all limbs on a chilled floor, whereas if a nerve is damaged, the limb comes in contact with cold the plate is significantly reduced. To quantify this parameter, the retention time of the limb on weight for 1 minute of the animal in the test chamber was recorded. The test was performed on the 10th day after the operation; each animal was tested three times with an interval of 5 minutes between measurements; the obtained values were averaged.

Statistical analysis: for each study group (n = 5), the average score obtained in the corresponding test and the standard error of the mean for each value were calculated. The significance of differences between the groups was evaluated using paired t-student test (at a significance level of p <0.05).

Results: the results obtained are shown in table 1 below.

Table 1. The effect of flupirtine and cyclobenzaprine, used individually or in combination, on the behavior of rats with pain syndrome that mimics static and functional diseases of the spine.

A drug Dose, mg / day Group No. the severity of mechanical allodynia, g (mean ± standard error of the mean) severity of cold allodynia, sec (mean ± standard error of the mean) carrier - placebo 2.6 ± 0.46 6.3 ± 0.89 flupirtine 25 one 9.0 ± 0.45 12.3 ± 1.85 300 2 10.2 ± 1.06 12.5 ± 0.88 600 3 11.3 ± 1.18 13.7 ± 2.02 cyclobenzaprine 1.25 four 8.7 ± 0.42 11.5 ± 1.76 fifteen 5 9.3 ± 0.42 12.6 ± 1.2 thirty 6 10.5 ± 0.94 13.0 ± 1.15 flupirtine +
cyclobenzaprine 25 + 1.25 7 * 20.5 ± 2.45 25.6 ± 2.33 300 + 15 8* 22.3 ± 2.33 27.3 ± 2.18 600 + 30 9* 26.0 ± 0 29 ± 3.46 diclofenac fifty 10 16.0 ± 2.16 20.0 ± 1.53

* significant difference from the expected (calculated) additive effect of the combination of flupirtine + cyclobenzaprine (significance level p <0.05).

Conclusion: in groups receiving a combination of flupirtine and cyclobenzaprine, the indicators of mechanical and cold allodynia are significantly reduced, which indicates the effectiveness of their use for the treatment of functional and static diseases of the spine. But in addition to this, a synergistic effect of the action of this combination was found at all tested dose levels.

Example 2. Evaluation of the effectiveness of a combination of flupirtine and cyclobenzaprine for the treatment of pain after injuries and surgical interventions.

Testing the effectiveness of drugs for the treatment of pain after injuries and surgical interventions (for example, for a hernia of the intervertebral disc or osteoarthritis of the hip joint) was performed on a model of postoperative pain in rats, formed by cutting the hind paw foot made through the skin, fascia and muscle [Brennan TJ, Vandermeulen EP, Gebhart GF “Characterization of a rat model of incisional pain” // Pain. 1996, 64: 493-501. Pogatzki E.M., Niemeier J.S., Brennan T.J. “Persistent secondary hyperalgesia after gastrocnemius incision in the rat” // Eur J Pain. 2002, 6: 295-305].

Rats: 55 adult male Sprague-Dawley rats having a body weight of 250-300 grams were used in the experiments. Rats were kept in five individuals in temperature-controlled boxes (with an average temperature of 21 ° C) at a 12-hour cycle of day and night and with sufficient water and food.

Description of the model: 3 days after the operation to transect the hind paw foot, which resulted in pain in rats, the efficacy of the test drugs for the treatment of this pain syndrome was studied in rats.

Surgery: Rats were anesthetized with isoflurane (Sigma, USA). The sole of the hind paw was treated with 10% povidone-iodine solution. Next, using a blade (number 11), a 1 cm longitudinal incision was made through the skin and fascia, starting at 0.5 cm below the proximal end of the heel in the direction of the fingers. The plantar muscle was raised and also cut in the longitudinal direction. Muscle attachment sites remained intact. 2 mattress sutures were applied to the wound using 5-0 nylon sutures and a FS-2 needle. The wound was treated with a mixture of antibiotics. After the operation, the animals recovered in their cages. Sutures were removed under anesthesia approximately 30 hours after surgery. Wounds healed, usually after 5-6 days.

Formation of study groups: rats were randomly assigned to 11 groups of equal composition (5 animals in each), differing in the type of drug administered and its dosage.

Introduced drugs and doses: the study was conducted for 3 drugs (flupirtine, cyclobenzaprine and diclofenac), which were administered orally 3 days after surgery and 30 minutes before the conduct of behavioral tests in the indicated doses and combinations: flupirtine, 25 mg / day (group No. 1 ); flupirtine, 300 mg / day (group No. 2); flupirtine, 600 mg / day (group No. 3); cyclobenzaprine, 1.25 mg / day (group No. 4); cyclobenzaprine, 15 mg / day (group No. 5); cyclobenzaprine, 30 mg / day (group No. 6); flupirtine, 25 mg / day + cyclobenzaprine, 1.25 mg / day (group No. 7); flupirtine, 300 mg / day + cyclobenzaprine, 15 mg / day (group No. 8); flupirtine, 600 mg / day + cyclobenzaprine, 30 mg / day (group No. 9); and diclofenac, 50 mg / day (group No. 10). The control was a group receiving only the carrier (placebo group). All doses are calculated per person.

Behavioral tests: to assess pain behavior, a von Frey filament test (the occurrence of mechanical allodynia) was used. Testing was performed as described in Example 1 above, except that the filaments were applied only to the injured leg.

Statistical analysis: for each study group (n = 5), the average score obtained in the test and the standard error of the mean for each value were calculated. The significance of differences between the groups was evaluated using paired t-student test (at a significance level of p <0.05).

Results: are shown in table 2 below.

Table 2. The effect of flupirtine and cyclobenzaprine, used individually or in combination, on the behavior of rats with pain after surgery.

A drug Dose, mg / day Group No. the severity of mechanical allodynia, grams (mean ± standard error of the mean) carrier - placebo 4.8 ± 1.54 flupirtine 25 one 11.4 ± 1.27 300 2 12.7 ± 0.44 600 3 14.1 ± 2.21 cyclobenzaprine 1.25 four 13.2 ± 2.04 fifteen 5 14.5 ± 0.52 thirty 6 15.6 ± 1.02 flupirtine +
cyclobenzaprine 25 + 1.25 7 * 24.8 ± 1.72 300 + 15 8* 25.2 ± 2.13 600 + 30 9* 25.8 ± 1.33 diclofenac fifty 10 17.2 ± 1.86

* significant difference from the expected (calculated) additive effect of the combination of flupirtine + cyclobenzaprine (significance level p <0.05).

Conclusions: in groups receiving a combination of flupirtine and cyclobenzaprine, the rate of mechanical allodynia is significantly reduced, which indicates the effectiveness of their use for the treatment of pain after surgery. The experiment also revealed a synergistic effect of the combination of flupirtine and cyclobenzaprine.

Example 3. Evaluation of the effectiveness of a combination of flupirtine and cyclobenzaprine for the treatment of skeletal muscle spasticity in neurological diseases.

The effectiveness of drugs for treating skeletal muscle spasticity in neurological diseases (for example, for multiple sclerosis, chronic myelopathy, degenerative diseases) was studied using a model of transection of the sacral spinal cord of the rat (formation of tail muscle spasticity) [Bennett DJ, Sanelli L., Cooke CL, Harvey PJ, Gorassini MA “Spastic long-lasting reflexes in the awake rat after sacral spinal cord injury” // J Neurophysiol. 2004, 91: 2247-2258. Li Y., Gorassini M.A., Bennett D.J. // Role of persistent sodium and calcium currents in motoneuron firing and spasticity in chronic spinal rats. J. Neurophysiol. 2004, 91: 767-783. Li X., Murray K., Harvey P.J., Ballou E.W., Bennett D.J. “Serotonin facilitates a persistent calcium current in motoneurons of rats with and without chronic spinal cord injury” // J Neurophysiol. 2007, 97: 1236-1246].

Rats: 55 adult male Sprague-Dawley rats having a body weight of 250-330 grams were used in the experiments. Rats were kept in five individuals in temperature-controlled boxes (with an average temperature of 21 ° C) at a 12-hour cycle of day and night and with sufficient water and food.

Model description: on the 15th day after the sacral spinal cord transection, tail spasticity was assessed in awake animals under mechanical stimulation.

Formation of study groups: rats were randomly assigned to 11 groups of equal composition (5 animals in each), differing in the type of drug administered and its dosage.

Introduced drugs and doses: the study was conducted for 3 drugs (flupirtine, cyclobenzaprine and diclofenac), which were administered 30 minutes before stimulation orally in the indicated doses and combinations: flupirtine, 25 mg / day (group No. 1); flupirtine, 300 mg / day (group No. 2); flupirtine, 600 mg / day (group No. 3); cyclobenzaprine, 1.25 mg / day (group No. 4); cyclobenzaprine, 15 mg / day (group No. 5); cyclobenzaprine, 30 mg / day (group No. 6); flupirtine, 25 mg / day + cyclobenzaprine, 1.25 mg / day (group No. 7); flupirtine, 300 mg / day + cyclobenzaprine, 15 mg / day (group No. 8); flupirtine, 600 mg / day + cyclobenzaprine, 30 mg / day (group No. 9); and diclofenac, 50 mg / day (group No. 10). The control was a group of rats receiving only the vehicle (placebo group). All doses are calculated per person.

Surgery: an experimental transection of the sacral spinal cord was performed at S2 level under anesthesia (isoflurane, Sigma, USA) under sterile conditions, as described previously [Bennett, et al., 1999]. Briefly, soft tissues were cut on the dorsal side of the spine, a laminectomy was performed at the L2 level of the lumbar vertebra. A sized hook was placed under the spinal cord, which was completely cut with scissors, avoiding damage to the veins and arteries. Layers of soft tissue tightly sewn to the spinal cord.

Assessment of tail spasticity: rats were placed in a Plexiglass cylinder so that the tail was stuck out and could move freely in the vertical direction. The tail was manually stimulated as follows: the base of the tail was clamped with the left hand, and in the right hand, holding the tail between the thumb and forefinger, quickly passed along the tail from the base to the tip, snug against it, and releasing the tail at the end of the movement. The procedure was repeated three times. This achieved longitudinal straightening of the tail. The response to such stimulation was the twisting of the tail with its removal under the body of the rat (or in the dorsal direction in rats with more severe injuries). To assess tail spasticity, the scale described below was used.

0-1 point: very slight or insignificant twisting of the tip of the tail in response to stretching (at an angle of less than 90 °, lasting only a few seconds), weak muscle tone or lack thereof, lack of clonus, lack of response to a light touch on the skin or coat.

2-3 points: a strong spasm (bending) of the tail in response to stimulation by stretching, the tip bends at an angle of 180-360 °, lasting 3-10 seconds. Repeated twisting and cloning of the tail lasts more than 10 minutes, hypertonicity, high sensitivity to light touch.

4-5 points: similar to the previous assessment, but the bending and bending of the tail is more often repeated, as a result of which the tail often acquires an S-shape, with the proximal part of the tail bending under the rat and the distal part in the opposite direction; more pronounced clonus, hypertonicity and side-to-side movements.

For each rat, a point was set on the tail spasticity scale, which was then averaged within the same group.

Statistical analysis: for each study group (n = 5), the average score on the spasticity scale and the standard error of the mean for each value were calculated. The obtained mean values were then compared using the paired Student t-test (at a significance level of p <0.05) to reveal statistical differences between the groups.

Results: the results are shown in table 3 below.

Table 3. The effect of flupirtine and cyclobenzaprine, used individually or in combination, on the behavior of rats experiencing pain due to spasticity of skeletal muscles.

A drug Dose, mg / day Group No. Spasticity average score ± standard error of the mean carrier - placebo 4.8 ± 0.19 flupirtine 25 one 2.9 ± 0.14 300 2 2.6 ± 0.23 600 3 2.5 ± 0.24 cyclobenzaprine 1.25 four 2.7 ± 0.21 fifteen 5 2.4 ± 0.23 thirty 6 2.2 ± 0.2 flupirtine +
cyclobenzaprine 25 + 1.25 7 * 1,0 ± 0 300 + 15 8* 0.8 ± 0.19 600 + 30 9* 0.7 ± 0.21 diclofenac fifty 10 0.9 ± 0.14

* significant difference from the expected (calculated) additive effect of the combination of flupirtine + cyclobenzaprine (significance level p <0.05).

Conclusions: the degree of tail spasticity in animals receiving a combination of flupirtine and cyclobenzaprine was most weakly expressed, which indicates the possibility of using this combination to treat skeletal muscle spasticity in neurological diseases. The experiment also revealed a synergistic effect of the combination of flupirtine and cyclobenzaprine.

Example 4. Evaluation of the effectiveness of a combination of flupirtine and cyclobenzaprine for the treatment of headache.

For this study, a rat-induced migraine model was selected that was induced by nitroglycerin [Sufka K.J., Staszko S.M., Johnson A.P., Davis M.E., Davis R.E., Smitherman T.A. “Clinically relevant behavioral endpoints in a recurrent nitroglycerin migraine model in rats” // J Headache Pain. 2016, 17: 40].

Rats: 55 adult male Sprague-Dawley rats having a body weight of 250-330 grams were used in the experiments. Rats were kept in five individuals in temperature-controlled boxes (with an average temperature of 21 ° C) at a 12-hour cycle of day and night and with sufficient water and food.

Formation of study groups: rats were randomly assigned to 11 groups of equal composition (5 animals in each), differing in the type of drug administered and its dosage.

Model description: migraine in rats was induced by intraperitoneal injection of a solution of nitroglycerin (Copperhead Chemical, USA) at a dose of 10 mg / 2 ml / kg of animal body weight for 2 weeks with a frequency of once every 3 days (5 injections in total). 30 minutes after each administration of nitroglycerin, the animals received the study drug in the indicated doses. 90 minutes after the last fifth administration, the condition of the animals was evaluated in the behavioral tests described below.

Introduced drugs and doses: the study was conducted for 3 drugs (flupirtine, cyclobenzaprine and diclofenac), which were administered 30 minutes after each administration of nitroglycerin orally in the indicated doses and combinations: flupirtine, 25 mg / day (group No. 1); flupirtine, 300 mg / day (group No. 2); flupirtine, 600 mg / day (group No. 3); cyclobenzaprine, 1.25 mg / day (group No. 4); cyclobenzaprine, 15 mg / day (group No. 5); cyclobenzaprine, 30 mg / day (group No. 6); flupirtine, 25 mg / day + cyclobenzaprine, 1.25 mg / day (group No. 7); flupirtine, 300 mg / day + cyclobenzaprine, 15 mg / day (group No. 8); flupirtine, 600 mg / day + cyclobenzaprine, 30 mg / day (group No. 9); and diclofenac, 50 mg / day (group No. 10). The control was a group of rats receiving only the vehicle (placebo group). All doses are calculated per person.

Behavioral tests: the severity of headache in each group of rats was investigated using two tests: avoidance of light in a dark-light chamber and a rating on the grimace scale compiled for rats.

The grimace scale for rats takes into account 4 noticeable changes in the facial expressions of rats: narrowing of the eyes, protruding cheeks, changing the shape of the ears, the direction of the vibrissa. Each of the parameters is estimated from photographs of rats, as previously described in detail [Sotocinal S., Sorge R., Zaloum A. et al. “The Rat Grimace Scale: A partially automated method for quantifying pain in the laboratory rat via facial expressions” // Mol Pain, 2011, 7:55] on a scale of 0 (no sign) to 2 (sign clearly pronounced). The total score determines the degree of pain experienced by the rat. The maximum possible score is 8. To take photographs, rats were placed in a 31x22x26 cm Plexiglass camera and a digital camera (Olympus Camedia C-5050 Zoom, Japan) was used.

The “dark-light chamber” test was carried out using the “dark-light chamber” installation, which consists of two compartments - dark (light inside ≤5 lux) and light (light inside ≥ 635 lux), separated by a partition with an opening for moving rats. The parameters of each compartment are 30x30x30 cm. The dark compartment of the camera is covered with a lid. Animals were placed in a brightly lit compartment for 5 min and time spent in the light and dark compartments was recorded. The experiment was recorded on a digital video camera (HDR-PJ820E, Sony, Japan). The more time the animal spends in the bright compartment, the less pronounced is the photophobia that accompanies migraine.

Statistical analysis: for each study group (n = 5), the average score obtained in the test with a dark-light camera, the average score on the grimace scale, and the standard error of the mean for each value were calculated. The obtained mean values were then compared using the paired Student t-test (at a significance level of p <0.05) to reveal statistical differences between the groups.

Results: the results obtained (group average) are shown in table 4 below.

Table 4. The effect of flupirtine and cyclobenzaprine, used individually or in combination, on the behavior of rats with headache.

A drug Dose, mg / day Group No. Time spent in the bright compartment, sec (mean ± standard error of the mean) Grimace score (mean ± standard error of the mean) carrier - placebo 15.1 ± 0.68 7.4 ± 0.4 flupirtine 25 one 23.5 ± 0.45 3.6 ± 0.6 300 2 25.6 ± 1.1 3.4 ± 0.51 600 3 24.9 ± 1.9 3.2 ± 0.49 cyclobenzaprine 1.25 four 21.8 ± 0.69 3 ± 0.63 fifteen 5 22.3 ± 0.54 2.8 ± 0.48 thirty 6 24.4 ± 0.86 2.6 ± 0.4 flupirtine +
cyclobenzaprine 25 + 1.25 7 * 42.1 ± 0.58 1.4 ± 0.6 300 + 15 8* 45.6 ± 0.76 1.2 ± 0.58 600 + 30 9* 50.9 ± 0.32 0.8 ± 0.49 diclofenac fifty 10 46.8 ± 1.0 2 ± 0.45

* significant difference from the expected (calculated) additive effect of the combination of flupirtine + cyclobenzaprine (significance level p <0.05).

Conclusions: in behavioral tests in the group of rats receiving a combination of flupirtine and cyclobenzaprine, the severity of headache was significantly lower than in all mono-administration groups and the placebo group. In addition, a synergistic effect of the combination of flupirtine and cyclobenzaprine was noted.

Example 5. Evaluation of the effectiveness of a combination of flupirtine and cyclobenzaprine for the treatment of pain associated with a malignant process.

Evaluation of the effectiveness of drugs for the treatment of pain associated with a malignant process was carried out on a model of pain caused by bone cancer in rats.

Rats: 55 adult female Sprague-Dawley rats having a body weight of 150-180 grams were used in the experiments. Rats were kept in five individuals in temperature-controlled boxes (with an average temperature of 21 ° C) at a 12-hour cycle of day and night and with sufficient water and food.

Description of the model: in this model, pain occurs due to the development of bone cancer. Bone cancer in rats was caused by implantation of breast carcinoma cells (MRMT-1 cell line) in the tibia [Medhurst SJ, Walker K., Bowes M., Kidd BL, Glatt M., Muller M., Hattenberger M., Vaxelaire J. , O'Reilly T., Wotherspoon G., Winter J., Green J., Urban L. “A rat model of bone cancer pain” // Pain. 2002, 96: 129-140]. After a certain time after implantation, behavioral tests recorded changes in responses to mechanical stimuli due to pain.

Formation of study groups: rats were randomly assigned to 11 groups of equal composition (5 animals in each), differing in the type of drug administered and its dosage.

Introduced drugs and doses: the study was conducted for 3 drugs (flupirtine, cyclobenzaprine and diclofenac), which were administered orally on day 15 after surgery in the indicated doses and combinations: flupirtine, 25 mg / day (group No. 1); flupirtine, 300 mg / day (group No. 2); flupirtine, 600 mg / day (group No. 3); cyclobenzaprine, 1.25 mg / day (group No. 4); cyclobenzaprine, 15 mg / day (group No. 5); cyclobenzaprine, 30 mg / day (group No. 6); flupirtine, 25 mg / day + cyclobenzaprine, 1.25 mg / day (group No. 7); flupirtine, 300 mg / day + cyclobenzaprine, 15 mg / day (group No. 8); flupirtine, 600 mg / day + cyclobenzaprine, 30 mg / day (group No. 9); and diclofenac, 50 mg / day (group No. 10). The control was a group of rats receiving only the vehicle (placebo group). All doses are calculated per person.

Cells: MRMT-1 rat breast carcinoma cells were cultured in medium containing RPMI 1640 (Sigma, USA; 500 ml), 10% (50 ml) fetal bovine serum (FBS, heat inactivated), 1% (5 ml) L- glutamine and 2% (10 ml) of penicillin / streptomycin. Immediately prior to injection, cells were detached from the plastic by short-term exposure to 0.1% (mass / volume) trypsin and collected by centrifugation of 10 ml of medium for 3 minutes at 1200 rpm. The resulting precipitate was washed twice with 10 ml of Hanks balanced salt solution (HBSS; Sigma, USA) that did not contain calcium, magnesium or phenol red, and centrifuged again for 3 minutes at 1200 rpm. The resulting pellet was resuspended in 1 ml of Hanks solution, and the number of cells in it was counted using a hemocytometer. Cells were diluted to a final concentration of 3x10 ⁴ cells / injection and kept on ice until administration to rats.

Surgical operation: rats were anesthetized with isoflurane (Sigma, USA), after which they were placed in a position with their stomach up, lying on their backs. Wool was shaved off the left hind paw of the rat, and the skin was disinfected with 70% (v / v) ethanol. Next, a rostrocaudal incision was made along the skin, 1 cm long, starting from the upper half of the tibia. The tibia was carefully released, being careful not to damage the muscles and blood vessels. Using a 23 gauge needle, the bone was pierced 5 mm below the knee joint, distal to the epiphyseal growth plate. The needle was held at an angle so that it could reach the intramedullary canal of the bone. The needle was then removed and replaced with a long thin blunt needle (Hamilton, a standard, screw-on metal blunt needle) attached to a 10-ml Hamilton syringe containing injected cells. In this way, 3 ml of cancer cells were injected into the bone cavity. Simultaneously with pressure on the plunger of the syringe, the needle was slowly pulled out of the bone so that the cells could fill the space in the bone cavity and did not extend beyond it. At the end of the procedure, the injection site was closed with bone wax (Ethicon, USA). The wound was closed using metal skin clamps (Becton Dickinson, USA) and treated with the antibiotic aureomycin. The animals were placed on a heated mattress until they regained consciousness, after which they were returned to their cages.

Behavioral test (weight distribution between the hind limbs): The pain that occurs in rats due to the development of bone cancer in them affects the behavior of animals in the test described below. The measurements were carried out on day 15 after implantation of rat breast carcinoma cells in the bone cavity of experimental animals and 30 minutes after administration of the studied drugs.

The distribution of body weight between the hind limbs was measured using a special device (disability tester, Columbus Instruments, USA), which is a small Plexiglas camera in which the animal is in a fixed position, and two plates with sensors on the bottom of the camera, each of which is placed one hind paw of the animal. The sensors within 3 seconds recorded the pressure created on them by the corresponding paw. Data on the distribution of weight on intact and damaged limbs (in grams) was expressed as a percentage of the total weight of the animal. For each rat, 2 measurements were made (with a difference of 10 minutes). The pain syndrome developing in cancer was accompanied by a decrease in the load on the injured limb.

Statistical analysis: for each study group (n = 5), the average load on each paw, expressed as a percentage of the total body weight of the animal, and the standard error of the mean were calculated. The obtained mean values were then compared using the paired Student t-test (at a significance level of p <0.05) to reveal statistical differences between the groups.

Results: the data obtained are shown in table 5 below. Less active use of the intact limb was observed in all studied groups compared with the placebo group. Moreover, the animals in the groups receiving a combination of flupirtine and cyclobenzaprine distributed the weight almost symmetrically with little preference for using an intact paw.

Table 5. The effect of flupirtine and cyclobenzaprine, used individually or in combination, on the behavior of rats suffering from pain associated with bone cancer.

A drug Dose, mg / day Group No. The distribution of body weight between the hind limbs (the average load in the group (in% of the animal’s body weight) per intact paw ± standard error of the mean) carrier - placebo 75.7 ± 1.57 flupirtine 25 one 65.2 ± 2 300 2 62.3 ± 1.68 600 3 61.4 ± 1.3 cyclobenzaprine 1.25 four 66.4 ± 1.79 fifteen 5 63.3 ± 1.56 thirty 6 62.5 ± 1.74 flupirtine +
cyclobenzaprine 25 + 1.25 7 * 55.4 ± 1.83 300 + 15 8* 53.6 ± 1.2 600 + 30 9* 52.9 ± 2 diclofenac fifty 10 67.9 ± 1.8

* significant difference from the expected (calculated) additive effect of the combination of flupirtine + cyclobenzaprine (significance level p <0.05)

Conclusions: in the behavioral test in the group of rats receiving a combination of flupirtine and cyclobenzaprine, the rates of pain associated with the malignant process were significantly lower than in all mono-administration groups and the placebo group. Moreover, the experiment showed a synergistic effect of the combination of flupirtine and cyclobenzaprine.

Example 6. Evaluation of the effectiveness of a combination of flupirtine and cyclobenzaprine for the treatment of dysmenorrhea and algomenorrhea.

The efficacy of a combination of flupirtine and cyclobenzaprine for the treatment of dysmenorrhea and algomenorrhea was evaluated in a model of uterine spasm induced by intraperitoneal administration of oxytocin to female mice after a 6-day preliminary administration of estradiol benzoate [Wang C., et al. “Pirt contributes to uterine contraction-induced pain in mice” // Molecular Pain. 2015, 11: 57].

Mice: The study involved 77 healthy female c57bl / 6 mice with a body weight of 15-20 grams. The animals were kept at 4 cages each, in a room with controlled temperature (20-24 ° C) and humidity (46-65%), while a 12-hour day / night cycle was observed and free access to water and food was provided.

Formation of study groups: mice were randomly divided into 11 groups of equal composition (7 animals each), differing in the type of drug administered and its dosage.

Introduced drugs and doses: the study was conducted for 3 drugs (flupirtine, cyclobenzaprine and diclofenac), which were administered orally 2 hours before the administration of oxytocin in the indicated doses and combinations: flupirtine, 25 mg / day (group No. 1); flupirtine, 300 mg / day (group No. 2); flupirtine, 600 mg / day (group No. 3); cyclobenzaprine, 1.25 mg / day (group No. 4); cyclobenzaprine, 15 mg / day (group No. 5); cyclobenzaprine, 30 mg / day (group No. 6); flupirtine, 25 mg / day + cyclobenzaprine, 1.25 mg / day (group No. 7); flupirtine, 300 mg / day + cyclobenzaprine, 15 mg / day (group No. 8); flupirtine, 600 mg / day + cyclobenzaprine, 30 mg / day (group No. 9); and diclofenac, 50 mg / day (group No. 10). The control was a group of mice receiving only the vehicle (placebo group). All doses are calculated per person.

Methodology: for 6 consecutive days in the morning (at 9 o’clock), female mice were injected with estradiol benzoate (Sigma, USA) by intraperitoneal injection at a dose of 0.01 g / kg / day. On the 7th day (one day after the end of the administration of estradiol benzoate) in the morning (at 9 o’clock), the studied preparations were orally administered to female mice in the above doses. 4 hours later, uterine spasm was caused in animals by an intraperitoneal injection of oxytocin at a dose of 0.01 l / kg. Animals were left alone for 10 minutes, after which they were observed in a behavioral test.

Behavioral test: within 80 minutes after the administration of oxytocin, animal behavior was recorded on a digital video camera (HDR-PJ820E, Sony, Japan). The manifestation of pain in this model is episodes of cramps - characteristic movements of animals, including contractions of the abdominal muscles, alternating with their relaxation, extension of the hind limbs and arching of the back. Researchers calculated the number of cramps in each group over the entire recording time.

Statistical analysis: for each study group (n = 7), the average value of the number of cramps and the standard error of the mean were calculated. The obtained mean values were then compared using the paired Student t-test (at a significance level of p <0.05) to reveal statistical differences between the groups.

Results: are shown in table 6 below.

Table 6. The effect of flupirtine and cyclobenzaprine, used individually or in combination, on the behavior in mice after induction of uterine spasm in them.

A drug Dose, mg / day Group No. The number of cramps (group average ± standard error of the mean) carrier - placebo 15 ± 0.5 flupirtine 25 one 7.9 ± 0.8 300 2 7.7 ± 0.7 600 3 7.2 ± 0.5 cyclobenzaprine 1.25 four 8.4 ± 1.6 fifteen 5 8.3 ± 1.1 thirty 6 8.0 ± 0.4 flupirtine +
cyclobenzaprine 25 + 1.25 7 * 4.1 ± 0.9 300 + 15 8 * 3.6 ± 0.3 600 + 30 9 * 3.1 ± 0.4 diclofenac fifty 10 6.3 ± 0.9

* significant difference from the expected (calculated) additive effect of the combination of flupirtine + cyclobenzaprine (significance level p <0.05).

Conclusion: The number of writhing during the 80-minute period after the administration of oxytocin in the group of mice receiving a combination of flupirtine and cyclobenzaprine was significantly lower than in the placebo group, and also significantly lower than in all mono-administration groups, which indicates the effectiveness of this combination for the treatment of dysmenorrhea and algomenorrhea. But in addition to this, a synergistic effect of the combination of flupirtine and cyclobenzaprine was also shown.

Example 7. The toxicity test of a combination of flupirtine and cyclobenzaprine.

It is known that with repeated administration of flupirtine in patients, the following most frequent side effects are observed: dizziness, general fatigue / weakness, heartburn, nausea, vomiting, dry mouth, headache, tremor [Harish S., et al. “Flupirtine: Clinical pharmacology” // J Anaesthesiol Clin Pharmacol. 2012, 28 (2): 172-177]. Similar side effects are indicated with prolonged use of cyclobenzaprine [Browning R., Jackson J.L., O’Malley P.G. "Cyclobenzaprine and back pain: a meta-analysis" // Archives of Internal Medicine. 2001, 161 (13): 1613-1620.]. The purpose of this study was to establish whether the combined use of flupirtine and cyclobenzaprine leads to an increase in these side effects.

Rats: in the experiments, 100 rats (50 males and 50 females) of the Spreg-Dowley line were used at the age of 8-9 weeks, having a body weight of 150-200 grams at the beginning of the study. Rats were kept in five individuals in temperature-controlled boxes (with an average temperature of 21 ° C) at a 12-hour cycle of day and night and with sufficient water and food.

Formation of study groups: rats were randomly divided into 10 groups of equal composition (5 males and 5 females in each group), differing in the type of drug administered and its dosage.

Test design: test substances were administered orally to male and female rats daily for 28 days at the doses indicated below. Clinical signs of intoxication, behavioral changes and body weight were recorded in animals throughout the study.

Introduced drugs and doses: the study was conducted for 2 drugs (flupirtine and cyclobenzaprine), which were administered orally daily for 28 days in the indicated doses and combinations: flupirtine, 25 mg / day (group No. 1); flupirtine, 300 mg / day (group No. 2); flupirtine, 600 mg / day (group No. 3); cyclobenzaprine, 1.25 mg / day (group No. 4); cyclobenzaprine, 15 mg / day (group No. 5); cyclobenzaprine, 30 mg / day (group No. 6); flupirtine, 25 mg / day + cyclobenzaprine, 1.25 mg / day (group No. 7); flupirtine, 300 mg / day + cyclobenzaprine, 15 mg / day (group No. 8); flupirtine, 600 mg / day + cyclobenzaprine, 30 mg / day (group No. 9). The control was a group of rats receiving only the vehicle (placebo group). All doses are calculated per person.

Determination of body weight: all animals were weighed at least 1 time per week. According to the results of each measurement, the average weight of animals in the group was calculated (separately for males, separately for females).

Food intake: recorded daily on average for each group of animals.

Behavioral tests: taking drugs can affect the quantity and quality of the motor activity of the animal. To assess this activity used the method of "open field". The Open Field is a well-lit circular arena with a diameter of 1.2 m and a height of 45 cm, the floor of which is marked by radial and circular lines. The rat was released into the central sector of the field and the total number of horizontal and vertical movements was recorded within 3 min.

Horizontal motor activity includes jogging along different trajectories, right up to whirling around one place. The main criterion for identifying this form of behavior is participation in the movement of the animal between the sectors of all four paws. Vertical motor activity was determined and calculated by the number of racks without dividing into a “stand with an emphasis” (the hind legs of the animal remain on the floor of the arena, and the front rest against the wall of the field) and “without emphasis” (the front legs remain in weight). The experiment was carried out on day 28 of the study, 90 minutes after administration of the drug. The effects of the drugs were evaluated by the degree of change in oligokinesia in this test.

To assess motor deficit and impaired coordination of movements, animals were placed on a horizontal rod with a diameter of 3 cm, which was rotated at a constant speed of 10 revolutions per minute or at an increasing speed - every 7 seconds per 1 revolution, where: initial speed - 5, final - 30 revolutions per a minute. The retention time of the animal on the rotating rod was recorded (for a maximum of 200 s). Previously, a single training was held to keep rats on the rod at a minimum rotation speed. Testing in a rotating rod was performed on day 28 of the study, 90 minutes after drug administration.

The appearance of signs of clinical intoxication: any other deviations from the normal state of the animals were recorded, for example, vomiting, refusal to eat, tremors, etc.

Statistical analysis: all data are presented as mean values for the group ± standard error of the mean. Differences between groups were evaluated using paired Student's t-test (at a significance level of p <0.05).

Results: presented in tables 7 and 8 below. In behavioral tests, there were no significant differences between mono-administration groups and groups receiving a combination of the studied drugs. Differences in body weight in rat groups were also not significant. Clinical signs of intoxication were not observed in any of the groups of animals receiving long-term flupirtine and cyclobenzaprine, in combination or separately at the indicated doses.

Table 7. Animal body weight

A drug Dose, mg / day Group No. Body weight, grams
(group average ± standard error of the mean) 14 day 28 day males females males females carrier - placebo 262 ± 2.7 210 ± 1.8 312 ± 3.7 250 ± 2.8 flupirtine 25 one 257 ± 2.0 223 ± 2.9 297 ± 4.1 244 ± 3.1 300 2 249 ± 2.5 195 ± 2.6 306 ± 2.9 259 ± 2.6 600 3 260 ± 1.9 201 ± 2.4 290 ± 3.4 247 ± 2.7 cyclobenzaprine 1.25 four 263 ± 2.8 215 ± 2.1 323 ± 4.6 243 ± 2.3 fifteen 5 256 ± 2.3 189 ± 2.9 309 ± 3.3 253 ± 3.0 thirty 6 251 ± 2.5 296 ± 2.6 289 ± 3.9 239 ± 2.9 flupirtine +
cyclobenzaprine 25 + 1.25 7 276 ± 1.8 206 ± 1.7 299 ± 2.8 245 ± 3.2 300 + 15 8 253 ± 2.1 198 ± 2.0 310 ± 4.2 251 ± 2.4 600 + 30 9 261 ± 2.8 208 ± 2.3 304 ± 3.6 261 ± 2.9

Table 8. The effect of drugs on motor activity and coordination of animals

A drug Dose, mg / day Group No. Number of vertical and horizontal movements Retention time on a rotating rod, seconds group average ± standard error of the mean carrier - placebo 78.07 ± 2.11 167.8 ± 8.6 flupirtine 25 one 73.21 ± 1.19 144.2 ± 9.3 300 2 70.23 ± 3.01 142.4 ± 7.2 600 3 64.90 ± 2.41 139.1 ± 4.3 cyclobenzaprine 1.25 four 65.45 ± 2.30 143.3 ± 4.9 fifteen 5 60.98 ± 2.55 139.6 ± 9.2 thirty 6 56.46 ± 1.98 136.2 ± 7.3 flupirtine +
cyclobenzaprine 25 + 1.25 7 * 76.46 ± 2.34 166.5 ± 4.8 300 + 15 8 * 74.69 ± 2.85 164.4 ± 8.7 600 + 30 9 * 70.44 ± 2.06 162.5 ± 5.6

* significant difference from the expected (calculated) additive effect of the combination of flupirtine + cyclobenzaprine (significance level p <0.05).

Conclusion: the use of the combination of flupirtine and cyclobenzaprine of the present invention leads to a statistically significant reduction in side effects associated with impaired coordination.

Example 8. Obtaining a drug in the form of tablets. 1600 mg of starch, 1600 mg of ground lactose, 400 mg of talc, 952.4 mg of flupirtine maleate and 47.6 mg of cyclobenzaprine hydrochloride are mixed and pressed into a block. The resulting bar is crushed into granules and sieved through sieves, collecting granules with a size of 14-16 mesh. The granules obtained are tabletted into a suitable tablet form weighing 560 mg each.

Example 9. Obtaining a drug in the form of capsules. Flupirtine, or its pharmaceutically acceptable salt, is thoroughly mixed with cyclobenzaprine, or its pharmaceutically acceptable salt, in a ratio of 20: 1. The resulting combination is mixed with lactose powder in a ratio of 2: 1. The resulting powder mixture is packaged in 300 mg gelatin capsules of the appropriate size.

Example 10. Obtaining a medicinal product in the form of injection compositions for intramuscular, intraperitoneal or subcutaneous injection. 952.4 mg of flupirtine maleate and 47.6 mg of cyclobenzaprine hydrochloride are mixed with 600 mg of chlorobutanol, 4 ml of propylene glycol and 200 ml of injection water. The resulting solution is filtered and placed in 1 ml ampoules, which are sealed.

The invention can be used in medicine, pharmacology.

Claims (22)

1. A combination for the treatment of pain syndromes, characterized in that the said combination contains in effective amounts flupirtine and cyclobenzaprine or their pharmaceutically acceptable salts, moreover, the introduction of the said combination is carried out orally and moreover, the active substances are contained in daily dosages: flupirtine - from 25 to 600 mg / day; cyclobenzaprine - from 1.25 to 30 mg / day. 2. The combination according to claim 1, characterized in that flupirtine and cyclobenzaprine are present in the form of sustained release tablets. 3. The combination according to claim 1, characterized in that the active substances are contained in preferred weight ratios flupirtine: cyclobenzaprine from 1: 1.2 to 480: 1. 4. A pharmaceutical composition for oral administration for the treatment of pain syndromes, characterized in that said composition contains in effective amounts a combination of flupirtine and cyclobenzaprine, or their pharmaceutically acceptable salts, as well as at least one excipient and / or at least one pharmaceutically acceptable the carrier, and the active substances are contained in mass ratios flupirtine: cyclobenzaprine from 1: 1.2 to 480: 1. 5. The composition according to p. 4, characterized in that the active substances are contained in daily dosages: flupirtine - from 25 to 600 mg / day; cyclobenzaprine - from 1.25 to 30 mg / day. 6. A kit for the treatment of pain syndromes, characterized in that said kit contains instructions for use and a pharmaceutical composition containing in an effective amount of cyclobenzaprine or a pharmaceutically acceptable salt thereof, at least one excipient and / or at least one pharmaceutically acceptable carrier, and a pharmaceutical composition comprising, in an effective amount, flupirtine or a pharmaceutically acceptable salt thereof and at least one excipient and / or at least one a pharmaceutically acceptable carrier, wherein administering the pharmaceutical composition of cyclobenzaprine or its pharmaceutically acceptable salt and the pharmaceutical composition of flupirtine or its pharmaceutically acceptable salt is administered orally, and wherein said kit contains from 25 to 600 mg / day. flupirtine and from 1.25 to 30 mg / day. cyclobenzaprine. 7. The use of a combination according to claim 1, a composition according to claim 4 or a kit according to claim 6 for the treatment of a pain syndrome selected from the group including: pain syndrome associated with static and functional diseases of the spine; pain after injuries and surgical interventions; pain syndrome associated with spasticity of skeletal muscles; pain associated with a malignant process; headache; dysmenorrhea and algomenorrhea. 8. The use according to claim 7, characterized in that the introduction of a combination according to claim 1, a composition according to claim 4 or a kit according to claim 6, is administered orally. 9. The use according to claim 7, characterized in that the active substances are administered in daily dosages: flupirtine - from 25 to 600 mg / day; cyclobenzaprine - from 1.25 to 30 mg / day.