Combination Therapy of Donepezil and Tadalafil for the Treatment of Alzheimer's Disease or Cognitive Impairment

Abstract

The present invention relates to a combination therapy of donepezil and tadalafil for the prevention, treatment, or amelioration of Alzheimer's disease or cognitive impairment. The combination therapy of donepezil and tadalafil according to the present invention has a superior effect on improving Alzheimer's disease or cognitive impairment compared to the administration of donepezil alone, and can therefore be useful as a treatment or combination drug for Alzheimer's disease or cognitive impairment.

Description

[Technical field]

[0001] The present invention relates to donepezil and tadalafil combination therapy for the treatment of Alzheimer's disease or cognitive impairment. [Background technology]

[0002] Cognitive impairment is a problem with the thought process and includes loss of reasoning ability, forgetfulness, learning disabilities, concentration problems, reduced intelligence, and other diminished mental functions. Cognitive impairment can be caused by disorders that occur during fetal development, birth, or shortly after birth, or at any point in life, particularly in newborns and young children, who may not be able to reveal the cause. Potential initial causes of cognitive impairment include chromosomal abnormalities and genetic syndromes, malnutrition, prenatal drug exposure, heavy metal contamination such as lead, hypoglycemia, neonatal jaundice, hypothyroidism, trauma or child abuse, reduced oxygen in the womb, and difficult or premature birth.

[0003] Dementia, a typical example of cognitive dysfunction, is a pathological phenomenon that is distinct from normal aging, and depending on its cause it can be classified into Alzheimer's disease, vascular dementia, dementia caused by alcoholism, dementia caused by trauma, dementia caused by aftereffects of Parkinson's disease, etc. Alzheimer's disease accounts for 50-70% of dementia-inducing diseases.

[0004] Acetylcholine is a neurotransmitter that acts not only in the central nervous system but also in the peripheral nervous system. A low level of acetylcholine expression is associated with diseases in which cognitive dysfunction plays a significant role, such as Alzheimer's disease. In fact, administration of donepezil, an acetylcholinesterase inhibitor, is one of the main treatment paradigms in Alzheimer's disease. Donepezil is used to treat mild to severe Alzheimer's disease and can be administered from 5 mg to 23 mg per day depending on the severity of the disease. It is well-established that the manifestation of cognitive signs and symptoms seen in Alzheimer's disease is partly related to a deficiency in cholinergic neurotransmission, and here it is speculated that donepezil exerts its therapeutic efficacy by increasing the concentration of acetylcholine in the brain through reversible inhibition of acetylcholinesterase (AChE). However, donepezil can only be used to slow the progression of the disease, and no treatment has yet been found to cure Alzheimer's disease, prevent the progression of the disease, or halt it. Also, donepezil is not useful for everyone with Alzheimer's disease, and may not be effective for many patients. Therefore, there is a high unmet need for treatments that more effectively treat Alzheimer's disease or cognitive impairment symptoms and modulate / slow the disease.

[0005] A recent (2020) review article has reported that nitric oxide (NO), which has dual neuroprotective and neurotoxic properties in the central nervous system, is partially involved in Alzheimer's disease, and that activation of the NO signaling pathway can contribute to alleviating altered neuroplasticity and memory decline in animal models of Alzheimer's disease by inducing phosphorylation of the transcription factor CREB (cAMP response element-binding protein) (the so-called NO / cGMP / PKG / CREB signaling pathway), thereby allowing PDE5 inhibitors to activate the pathway and cure memory impairment (reference [Zuccarello, Elisa, et al. "Development of novel phosphodiesterase 5 inhibitors for the therapy of Alzheimer's disease." Biochemical Pharmacology 176 (2020): 113-818.]).

[0006] However, the specific combination and ratio of donepezil and PDE5 inhibitor that can prevent, treat or improve symptoms of Alzheimer's disease or cognitive impairment are not known. Therefore, the present inventors have confirmed that a specific combination ratio of tadalafil, which is one of PDE5 inhibitors, and donepezil can prevent, treat or improve symptoms of Alzheimer's disease or cognitive impairment, and have completed the present invention. Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a use of combined administration of donepezil and tadalafil for the prevention or treatment of Alzheimer's disease or cognitive impairment.

[0008] It is still another object of the present invention to provide a use of the combined administration of donepezil and tadalafil for improving cognitive function. [Means for solving the problem]

[0009] As a result of intensive research into the present invention in order to achieve the above-mentioned object, it was confirmed that when donepezil and tadalafil are administered in combination, the preventive or therapeutic effect for Alzheimer's disease or cognitive impairment is improved compared to when donepezil is administered alone, and thus the present invention has been completed.

[0010] In one aspect, the present invention provides a composition for preventing, treating, or ameliorating Alzheimer's disease or cognitive impairment, comprising: (i) donepezil or a pharma- ceutical acceptable salt thereof; and (ii) tadalafil or a pharma- ceutical acceptable salt thereof.

[0011] In the composition, the weight ratio of (i) donepezil or a pharma- ceutically acceptable salt thereof; and (ii) tadalafil or a pharma- ceutically acceptable salt thereof may be from 5:1 to 30:1.

[0012] The composition may be administered simultaneously or at different times, comprising (i) donepezil or a pharma- ceutically acceptable salt thereof, and (ii) tadalafil or a pharma- ceutically acceptable salt thereof. When the compositions are administered simultaneously, the composition may be in the form of a combination dosage form comprising (i) donepezil or a pharma- ceutically acceptable salt thereof, and (ii) tadalafil or a pharma- ceutically acceptable salt thereof.

[0013] When the composition is a combination dosage form, the combination dosage form may contain: (i) 2.5 to 23 mg of donepezil or a pharma- ceutically acceptable salt thereof; and (ii) 0.1 to 2.5 mg of tadalafil or a pharma- ceutically acceptable salt thereof.

[0014] The composition may be a pharmaceutical composition or a food composition.

[0015] In another aspect, the present invention provides a composition for improving cognitive function, comprising: (i) donepezil or a pharma- ceutical acceptable salt thereof; and (ii) tadalafil or a pharma-ceutical acceptable salt thereof.

[0016] In the composition for improving cognitive function, the weight ratio of (i) donepezil or a pharma- ceutically acceptable salt thereof; and (ii) tadalafil or a pharma- ceutically acceptable salt thereof may be 5:1 to 30:1.

[0017] In one aspect, the present invention provides a method for preventing, treating, or ameliorating Alzheimer's disease or cognitive impairment, comprising co-administering effective amounts of (i) donepezil, or a pharma- ceutical acceptable salt thereof; and (ii) tadalafil, or a pharma- ceutical acceptable salt thereof.

[0018] In one aspect, the present invention provides a method for improving cognitive function, comprising co-administering effective amounts of (i) donepezil, or a pharma- ceutically acceptable salt thereof; and (ii) tadalafil, or a pharma- ceutically acceptable salt thereof. Effect of the Invention

[0019] The combined administration of donepezil and tadalafil according to the present invention is more effective in improving Alzheimer's disease or cognitive impairment than the administration of donepezil alone, and can therefore be usefully used as a preventive, ameliorative or therapeutic therapy or combination drug for Alzheimer's disease or cognitive impairment. [Brief description of the drawings]

[0020] [Figure 1A] 1 shows the results of synaptic long-term potentiation (LTP) experiments after combined treatment with donepezil and tadalafil in animal models of Alzheimer's disease or cognitive impairment. [Figure 1B] Same as above. [Figure 2A]1 shows the results of a water maze experiment following co-administration of donepezil and tadalafil in an animal model of Alzheimer's disease or cognitive impairment. [Figure 2B] Same as above. [Diagram 3] 1 shows the results of a Y-maze experiment after co-administration of donepezil and tadalafil in an animal model of Alzheimer's disease or cognitive impairment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. However, the following examples are presented as examples of the present invention, and if a detailed description of a well-known technology or configuration well known to those skilled in the art is deemed to unnecessarily obscure the gist of the present invention, the detailed description may be omitted and the present invention is not limited thereby. The present invention is subject to various modifications and applications within the scope of the claims and the scope of equivalents interpreted therefrom.

[0022] In addition, the terminology used in this specification is used to appropriately express the preferred embodiment of the present invention, and may vary depending on the intention of the user or operator, or the practice of the field to which the present invention belongs. Therefore, the definition of the term should be based on the contents of the entire specification. In the entire specification, when a part "includes" a certain element, this does not exclude other elements, but means that the part may further include other elements, unless otherwise specified to the contrary.

[0023] All technical terms used in the present invention are used in the same sense as commonly understood by those of ordinary skill in the art in the field of the present invention unless otherwise specified. In addition, although preferred methods or samples are described in this specification, similar or equivalent methods or samples are also included in the scope of the present invention. The contents of all publications mentioned as references in this specification are incorporated herein.

[0024] The present inventors have confirmed that the effect of treating Alzheimer's disease or cognitive impairment is improved when donepezil is administered in combination with tadalafil, as compared to when donepezil is administered alone, and have thus completed the present invention.

[0025] Thus, the present invention provides a composition for preventing, treating, or ameliorating Alzheimer's disease or cognitive impairment, comprising (i) donepezil or a pharma- ceutical acceptable salt thereof; and (ii) tadalafil or a pharma- ceutical acceptable salt thereof.

[0026] In the present invention, the term donepezil refers to a compound represented by the following formula 1.

[0027] [ka]

[0028] Donepezil or a pharma- ceutically acceptable salt thereof is an acetylcholinesterase inhibitor (ACEi), and is orally administered at 5 to 23 mg of donepezil hydrochloride once a day, and is known to be usable for treating symptoms of Alzheimer's dementia.

[0029] In the present invention, the term tadalafil refers to a compound represented by the following formula 2.

[0030] [ka]

[0031] Tadalafil or a pharma- ceutically acceptable salt thereof is a phosphodiesterase 5 (PDE5) inhibitor, and is known to be administered to men at 5 to 20 mg per day for use in treating erectile dysfunction. In the present invention, tadalafil is a PDE5 inhibitor that is used in combination with other drugs belonging to the competitive PDE inhibitors, such as PDE1 inhibitors (e.g., vinpocetine), PDE2 inhibitors (e.g., EHNA (erythro-9-(2-hydroxy-3-nonyl)adenine), BAY, etc.). 60-7550 (2-[(3,4-dimethoxyphenyl)methyl]-7-[(1R)-1-hydroxyethyl]-4-phenylbutyl]-5-methyl-imidazo[5,1-f][1,2,4]triazin-4(1H)-one), oxindole, PDP (9-(6-phenyl-2-oxohex-3-yl)-2-(3,4-dimethoxybenzyl)-purin-6-one)), PDE3 inhibitors (e.g., anagrelide, cilostazol, enolate Tadalafil is mechanistically distinct from PDE4 inhibitors (e.g., apremilast, drotaverine, ibudilast, luteolin, mesembrine, piclamilast, roflumilast, rolipram), PDE6 inhibitors, PDE7 inhibitors (e.g., quinazolines), PDE8 inhibitors, PDE9 inhibitors, PDE10 inhibitors (e.g., papaverine), PDE11 inhibitors, PDE12 inhibitors, or combinations thereof. It is also distinct from PDE5 inhibitors, e.g., avanafil, dipyridamole, icariin, sildenafil, udenafil, vardenafil, which differ in chemical structure and functional properties from tadalafil.

[0032] In the present invention, Alzheimer's disease is a neurodegenerative disease that is the main cause of dementia, and has the same meaning as commonly used in the art.

[0033] In the present invention, cognitive dysfunction refers to a problem occurring in a person's thought processing process, and is a concept that includes loss of reasoning ability, forgetfulness, learning disabilities, concentration problems, decreased intelligence, and other declines in mental functions.

[0034] In the present invention, the term pharma- ceutically acceptable salt refers to any organic or inorganic addition salt that has a relatively non-toxic and harmless effective effect on the patient, and the side effects caused by the salt do not reduce the beneficial efficacy of the pharmacologically active ingredient. The pharma- ceutically acceptable salt includes salts derived from pharma- ceutical acceptable acids or bases. The acid that can be used to prepare the pharma- ceutical acceptable salt may be an inorganic acid or an organic acid. Examples of inorganic acids that can be used include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, perchloric acid, bromic acid, etc., and examples of organic acids that can be used include, but are not limited to, acetic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, fumaric acid, maleic acid, malonic acid, phthalic acid, succinic acid, lactic acid, citric acid, citronic acid, gluconic acid, tartaric acid, salicylic acid, malic acid, oxalic acid, benzoic acid, embonic acid, aspartic acid, glutamic acid, etc. In addition, the pharma- ceutically acceptable salt of the present invention may also include amino acid addition bases prepared using natural amino acids such as alanine and glycine. In addition, the base that can be used to prepare the pharma-ceutically acceptable salt may be, for example, tris(hydroxymethyl)methylamine, dicyclohexylamine, etc., but is not limited thereto. For example, the pharma-ceutically acceptable salt of donepezil may be, for example, donepezil hydrochloride, but is not limited thereto.

[0035] In the pharmaceutical composition of the present invention, the pharma- ceutically acceptable salt of donepezil and / or tadalafil may also include hydrates and solvates of donepezil and / or tadalafil. The hydrates or solvates may be formed by dissolving donepezil and / or tadalafil in a water-miscible solvent such as methanol, ethanol, acetone, 1,4-dioxane, and then adding a free acid or free base, followed by crystallization or recrystallization, but are not limited thereto.

[0036] In the pharmaceutical composition for preventing or treating Alzheimer's disease of the present invention, the weight ratio of (i) donepezil or a pharma- ceutically acceptable salt thereof; and (ii) tadalafil or a pharma- ceutically acceptable salt thereof may be 5:1 to 30:1. More specifically, in the pharmaceutical composition for preventing or treating Alzheimer's disease of the present invention, the weight ratio of (i) donepezil or a pharma- ceutically acceptable salt thereof; and (ii) tadalafil or a pharma- ceutically acceptable salt thereof may be 5:1 or more, 6:1 or more, 7:1 or more, 8:1 or more, or 9:1 or more, and may be 30:1 or less, 25:1 or less, 20:1 or less, 15:1 or less, or 12:1 or less. In one embodiment, the weight ratio of (i) donepezil or a pharma- ceutically acceptable salt thereof; and (ii) tadalafil or a pharma- ceutically acceptable salt thereof is about 5:1 to 10:1.

[0037] Since the molecular weights of donepezil and tadalafil are approximately the same, molar ratio and weight ratio can be used interchangeably herein.

[0038] The present inventors have confirmed that the combination of donepezil and tadalafil at various weight ratios was administered to brain slices of animal models of Alzheimer's disease or cognitive impairment, and that the changes in synaptic plasticity were significantly improved compared to the group treated with donepezil alone (FIGS. 1A-1B). Specifically, the present inventors have confirmed that the effect of improving Alzheimer's disease or cognitive impairment was excellent when the weight ratio of donepezil and tadalafil was in the range of about 5:1 to 30:1.

[0039] Furthermore, the present inventors confirmed through a water maze experiment, which is an animal behavioral experiment on Alzheimer's disease or cognitive dysfunction, that the behavioral indicators of improvement of Alzheimer's disease or cognitive dysfunction were significantly improved when donepezil and tadalafil were administered in combination (FIGS. 2A, 2B, and 3).

[0040] Specifically, in the examples of the present invention, when 2 mg / kg donepezil and 0.2 mg / kg tadalafil were co-administered to mice with Alzheimer's disease or cognitive impairment models, it was confirmed that the results of the water maze experiment (FIGS. 2A and 2B) and the Y maze experiment (FIG. 3) were significantly improved. In particular, when 1 mg / kg donepezil and 0.2 mg / kg tadalafil were co-administered to mice with disease models, the surprising result was that the indicators of Alzheimer's disease or cognitive impairment were improved to the same level as in the group administered 2 mg / kg donepezil alone (FIGS. 2A and 2B).

[0041] Therefore, the optimal animal administration dose confirmed in the present invention, the mouse-human dose-response relationship, and the NOAEL (No-observed-adverse-effect level) can be considered to convert the preferred administration dose in humans. The dose conversion standard can be the HED (Human equivalent dose) calculation method described in the literature [FDA, US. "Guidance for Industry, Estimating the maximum safe starting dose in initial clinical trials for therapeutics in adult healthy volunteers." FDA, ed (2005).]. The mouse-human dose conversion coefficient presented in the literature is 12.3, and the dose of the drug confirmed in mice (a) is divided by the conversion coefficient to derive a dose of a / 12.3 (mg / kg). Generally, pharmaceuticals are made based on a 60 kg adult, so that a pharmaceutical composition to be administered to humans can be made at a dose of about 5 x a (mg) by multiplying the value of a / 12.3 (mg / kg) derived above by 60 kg. Therefore, with reference to the optimal mouse dose ratio of donepezil and tadalafil confirmed in the examples of the present invention, a preferred drug dose ratio to be administered to humans can be derived.

[0042] When the donepezil and tadalafil combination composition of the present invention is provided as a combined dosage form, the preferred weights of donepezil and tadalafil can be set by comprehensively considering the above-mentioned mouse-human dose conversion formula and the dose of donepezil whose safety has been established. In one embodiment, the weight of donepezil contained in the combined dosage form is 2.5-23 mg, and the weight of tadalafil is 0.1-2.5 mg.

[0043] The pharmaceutical composition of the present invention may be administered in a therapeutically effective amount. The therapeutically effective amount means a drug dosage that effectively prevents or treats Alzheimer's disease or cognitive impairment. The appropriate total daily dosage may be determined by the treating physician within the scope of sound medical judgment. The specific therapeutically effective amount for a particular patient is preferably applied differently depending on various factors including the type and degree of response to be achieved, the type and amount of co-administered drugs, the specific composition including whether other preparations are used, the age, weight, general health condition, sex and diet of the patient, administration time, administration route, treatment period, and similar factors known in the medical field.

[0044] The pharmaceutical composition of the present invention can be administered orally or parenterally, preferably orally. The pharmaceutical composition of the present invention can also be used in combination with one or more central nervous system drugs.

[0045] In the composition of the present invention, donepezil and tadalafil can be administered alone as pure compounds or together with pharma- ceutical acceptable carriers or excipients, in single or multiple doses.The pharmaceutical composition according to the present invention can be formulated together with pharma- ceutical acceptable carriers or diluents as well as any other known adjuvants and excipients according to conventional techniques, for example those disclosed in the literature [Remington: The Science and Practice of Pharmacy, 21st Edition, Hauber, Ed., Lippincott Williams & Wilkins, 2006].

[0046] The pharmaceutical composition of the present invention may include pharma- ceutically acceptable carriers, excipients, and / or diluents for administration, including, but not limited to, lactose, dextrose, sucrose, sorbitol, mannitol, xylitol, erythritol, maltitol, starch, acacia gum, alginic acid, gelatin, calcium phosphate, calcium silicate, cellulose, methylcellulose, microcrystalline cellulose, polyvinylpyrrolidone, water, methyl hydroxybenzoate, propyl hydroxybenzoate, talc, magnesium stearate, and mineral oil.

[0047] The pharmaceutical composition of the present invention can be prepared in a pharmaceutical dosage form by using a method widely known in the art. In preparing the dosage form, the active ingredient can be mixed or diluted with a carrier, or can be enclosed in a carrier in a container form. When the pharmaceutical composition of the present invention is prepared in a dosage form for oral administration, it can be prepared, for example, into tablets, troches, lozenges, aqueous or oily suspensions, prepared powders or granules, emulsions, hard or soft capsules, syrups or elixirs.

[0048] In one aspect, the present invention provides a method for preventing or treating Alzheimer's disease or cognitive impairment, comprising administering to a patient a therapeutically effective amount of donepezil and tadalafil. In another aspect, the present invention provides a use of donepezil and tadalafil in the manufacture of a medicament for preventing or treating Alzheimer's disease or cognitive impairment. The donepezil and tadalafil, salts, etc. are as described above.

[0049] In one aspect, the present invention provides a combination for preventing, treating, or ameliorating Alzheimer's disease or a cognitive impairment disorder, comprising a first formulation comprising donepezil and a second formulation comprising tadalafil.

[0050] In the present invention, the term combination refers to a combination in the sense of a combination of two or more active substances in a dosage form and in the sense of separate dosage forms of the active substances administered at a specified interval from each other in a treatment. Thus, the term combination, when described in connection with the present invention, includes the clinical realization of the simultaneous administration of two or more therapeutically effective compounds.

[0051] In the combination of the present invention, the first formulation and / or the second formulation can each be administered parenterally or orally, preferably orally.

[0052] In the combination of the present invention, the first formulation and the second formulation may be administered simultaneously or at different times.

[0053] The combination of the present invention may be a combined dosage form comprising a first formulation and a second formulation, specifically an orally administered combined dosage form.

[0054] In one aspect, the present invention provides a composition for aiding in the improvement of Alzheimer's disease or cognitive impairment, comprising donepezil and tadalafil or a pharma- ceutical acceptable salt thereof.

[0055] In the present invention, the term "adjunctive use" refers to a use in which the preventive, therapeutic or ameliorative effect of a drug administered as an adjunct alone is relatively low, but when administered in combination with other central nervous system drugs, the preventive, therapeutic or ameliorative effect of Alzheimer's disease or cognitive impairment is significantly improved.

[0056] The composition of the present invention may be a pharmaceutical composition or a food composition. When the composition is used as a food composition, donepezil, tadalafil or a pharma- ceutically acceptable salt thereof may be added as is or may be used together with other foods or food ingredients, and may be used appropriately according to a conventional method. The composition may contain a food-scientifically acceptable food supplement additive in addition to the active ingredient, and the amount of the active ingredient to be mixed may be appropriately determined according to the purpose of use (prevention, health or therapeutic treatment).

[0057] The food composition of the present invention may include a functional health food. In the present invention, the term "functional health food" refers to a food produced and processed in the form of tablets, capsules, powders, granules, liquids, pills, etc., using raw materials or ingredients that have useful functions for the human body. Here, "functionality" means that it obtains useful effects for health applications, such as regulating nutrients for the structure and function of the human body, or physiological effects.

[0058] In addition, the composition of the present invention can be used in any type of health food. In addition, the composition of the present invention containing donepezil and / or tadalafil as an active ingredient can be prepared by mixing other suitable auxiliary ingredients and known additives that can be included in health functional foods according to the selection of a person skilled in the art. Examples of foods that can be added include meat, sausage, bread, chocolate, candy, snacks, confectionery, pizza, ramen, other noodles, gums, dairy products including ice cream, various soups, drinking water, tea, energy drinks, alcoholic beverages and vitamin complexes, and can be added to extracts, teas, jellies and juices produced using the extract of the present invention as the main ingredient.

[0059] All references to compositions, methods of treatment, and uses of the present invention apply equally unless they contradict each other.

[0060] The present invention will be described in more detail with reference to the following examples, which are merely for illustrative purposes and are not intended to limit the scope of the present invention. EXAMPLES

[0061] Example 1: Confirmation of synaptic plasticity enhancement effect by combined administration of donepezil and tadalafil in animal models of Alzheimer's disease or cognitive impairment To confirm synaptic plasticity due to the combined administration of donepezil and tadalafil, subjects were divided into three groups: (1) DMSO group (n=4) used as a control group, (2) amyloid beta group (n=4), (3) amyloid beta + donepezil (100 nM) alone treatment group (n=4), and (4) to (7) amyloid beta + donepezil (100 nM) + tadalafil (1, 3, 10, 100 nM) combined treatment groups (n=4 for each group), and local field recordings were measured on brain slices from each group.

[0062] Neurons in the brain transmit information through junctions called synapses. The process by which synapses strengthen or weaken (synaptic plasticity) is an important process for learning and memory. The sustained improvement in the size and activity of synapses is called long-term synaptic potentiation (LTP), a typical example of synaptic plasticity. LTP is an important mechanism for higher cognitive functions, and damage to LTP is known to be a typical symptom of dementia.

[0063] In order to confirm the effect of donepezil and combined administration according to the present invention on the treatment of Alzheimer's disease or cognitive impairment, changes in synaptic long-term potentiation (LTP) were evaluated in brain tissue slices from Alzheimer's disease model mice.

[0064] Specifically, to construct models of Alzheimer's disease or cognitive impairment, mouse brain slices were treated with 3 μM amyloid beta (Aβ), the main component of amyloid plaques found in the brains of Alzheimer's patients and known to be the main cause of cognitive impairment.

[0065] As a result of the experiment, it was confirmed that synaptic long-term potentiation (LTP) was significantly improved in the donepezil and tadalafil combined treatment group compared to the donepezil alone treatment group (Figure 1A). In particular, the LTP effect was compared and measured at various weight ratios of donepezil and tadalafil, and it was confirmed that the most effective was in the donepezil:tadalafil weight ratio range of 5:1 to 30:1 (Table 1 or Figure 1B).

[0066] [Table 1]

[0067] The data in the table show that synaptic long-term potentiation increased by 5.71% in the donepezil alone group and by 25.22% in the donepezil and tadalafil (tadalafil 10 nM) combination treatment group relative to the amyloid beta group.

[0068] This indicates that the combination of donepezil and tadalafil according to the present invention has improved therapeutic effects on Alzheimer's disease or cognitive impairment compared to donepezil in the process of hippocampal synaptic long-term potentiation, which is known to be deeply involved in the mechanism of memory.

[0069] <Example 2> Confirmation of the effect of combined administration of donepezil and tadalafil on improving water maze test indices in animal models of Alzheimer's disease or cognitive impairment The 5xFAD mice used in this study are genetically modified mouse models in which Alzheimer's disease-inducing genes have been inserted. Specifically, amyloid precursor proteins with Swedish (K670N, M671L), Florida (I716V), and London (V717I) mutations, and PS1 with M146L and L286V mutations are all overexpressed. 5xFAD mice are the most widely used mouse model that exhibits symptoms of Alzheimer's disease.

[0070] A water maze experiment was conducted to test the effect of administering the composite composition of the present invention on improving cognitive function. The experimental equipment consisted of a circular tank (diameter 150 cm, height 45 cm) filled with water at a temperature of about 22±2°C, an escape platform (diameter 10 cm, height 30 cm), and four signs attached to the wall that allow the location of the escape platform to be memorized. The signs remained unchanged throughout the entire test period. The escape platform was located 1 cm above the water surface or 0.5-1.5 cm below the water surface according to the purpose of the experiment. When located below the water surface, the water was made opaque with white water-based paint so that the escape platform could not be seen with the naked eye. The water maze was divided into four quadrants, northeast (NE), northwest (NW), southeast (SE), and southwest (SW), and the escape platform was placed in the center of the southwest quadrant, and one of the remaining quadrants was used randomly as the starting position. The location of the escape platform did not change throughout the learning period.

[0071] On learning day 0, the escape platform was visible. Each mouse was trained to recognize that it was possible to escape by swimming toward the escape platform and climbing onto it. On days 1 to 4, the escape platform was placed under the water and hidden, and then the mouse was allowed to learn the location of the escape platform. A time limit of 60 seconds was set, and if the animal found the escape platform within 60 seconds, it was allowed to remain on the escape platform for 5 seconds. It was then immediately moved to its breeding cage. On day 5, an experiment was conducted without the escape platform. The mouse was placed at the farthest point from the four image limits where the escape platform was placed during the learning period, and the time limit was set to 60 seconds. The escape latency, which is the time it took for the mouse to find the escape platform, and the time it stayed in the four image limits where the escape platform was located (Time spent in quadrant), were used as test indices. The shorter the time it took to escape (FIG. 2A) and the longer the mouse stayed in the four image regions where the escape platform was located (FIG. 2B), the better the memory and learning ability of the mouse was judged to be.

[0072] To confirm the effect of the combined administration of Donepezil and Tadalafil on cognitive function improvement, the mice were divided into the following groups: (1) normal mice (WT vehicle, 0.5% methylcellulose 5ml / kg, n=5), (2) mutant mice (MT vehicle, 0.5% methylcellulose 5ml / kg, n=5), (3) MT Donepezil (1mg / kg alone, n=4), (4) MT Donepezil (2mg / kg alone, n=5), and (5)~(6) MT Donepezil + Tadalafil (1mg / kg + 0.2mg / kg combined, n=4 and 2mg / kg + 0.2mg / kg combined, n=5). Each group was orally administered with Donepezil for 4 weeks.

[0073] As a result, when compared with the mutant mouse vehicle-administered group during the escape latency on the final day of learning (DAY 4), it was shown that the escape latency time was significantly reduced in the donepezil and tadalafil combined administration group compared with the mutant mouse groups administered donepezil 1 mg / kg and 2 mg / kg alone (Table 2 or Figure 2A).

[0074] [Table 2]

[0075] The data in the above table show that the escape latency was reduced by 33.79% in the donepezil 2 mg / kg alone group and by 76.39% in the donepezil 2 mg / kg and tadalafil 0.2 mg / kg combined group, based on the mutant mouse vehicle group.

[0076] In addition, it was confirmed that the time spent in the four quadrants was significantly increased in the donepezil and tadalafil combination treatment group (donepezil 2 mg / kg and tadalafil 0.2 mg / kg) compared to the donepezil alone treatment group of mutant mice (Table 3 or Figure 2B).

[0077] [Table 3]

[0078] The data in the above table show that the time spent in the four target quadrants was increased by 148.46% for the mutant mouse vehicle group treated with donepezil 2 mg / kg alone and by 274.46% for the combined treatment with donepezil 2 mg / kg and tadalafil 0.2 mg / kg.

[0079] This indicates that the combined administration of donepezil and tadalafil significantly improved memory and learning ability compared to the improvement effect of the administration of donepezil alone. In particular, it was confirmed that the improvement effect of cognitive function was maximized in the combined administration group when the weight ratio of donepezil to tadalafil was in the range of 5:1 to 30:1, as confirmed in Figure 1B.

[0080] Example 3: Confirmation of the effect of combined administration of donepezil and tadalafil on improving Y-maze test indices in animal models of Alzheimer's disease or cognitive impairment In order to test the effect of administration of the composite composition of the present invention on improving short-term working memory ability, a Y-maze experiment was performed using the above-mentioned Alzheimer's mouse model. The experimental equipment used was a Y-shaped maze (36 cm wide, 16 cm long, 15 cm high) divided into three areas, and the three areas were randomly used as starting positions. The mouse was placed in the maze, and the number of times the center of the mouse's body entered each area and the number of times each area was entered in sequence were counted. Alternation was defined as entering the three areas in sequence without overlapping, and spontaneous alternation was calculated using the following formula.

[0081] Alternation(%) = (number of times each area was entered in sequence / number of times all areas were entered - 2) x 100

[0082] To confirm the cognitive function-improving effect of the combined administration of Donepezil and Tadalafil, mice were divided into (1) normal mice vehicle (referred to as WT vehicle, 0.5% methylcellulose 5 ml / kg, n=6), (2) mutant mice vehicle (referred to as MT vehicle, 0.5% methylcellulose 5 ml / kg, n=6), (3) MT Donepezil (2 mg / kg alone, n=5), and (4) MT Donepezil + Tadalafil (2 mg / kg Donepezil + 0.2 mg / kg Tadalafil combined, n=5) groups, and the mice were orally administered with Donepezil and Tadalafil, and experiments were performed.

[0083] As a result, it was confirmed that working memory was significantly improved in the donepezil and tadalafil combination group compared to the donepezil alone group (Table 4 or Figure 3).

[0084] [Table 4]

[0085] The data in the above table show that spontaneous alternation activity increased by 25.15% in the donepezil 2 mg / kg alone group and by 62.46% in the donepezil 2 mg / kg and tadalafil 0.2 mg / kg combined group, based on the mutant mouse vehicle group.

Claims

1. (i) donepezil or a pharma- ceutically acceptable salt thereof; and (ii) tadalafil or a pharma- ceutically acceptable salt thereof Including, the weight ratio of (i) donepezil or a pharma- ceutical acceptable salt thereof to (ii) tadalafil or a pharma-ceutical acceptable salt thereof is 5:1 to 20:1; A composition for preventing, treating or ameliorating Alzheimer's disease or cognitive impairment.

2. 2. The composition of claim 1, which is a combination dosage form comprising: (i) donepezil or a pharma- ceutically acceptable salt thereof; and (ii) tadalafil or a pharma- ceutically acceptable salt thereof.

3. 3. The composition of claim 2, wherein the combination dosage form comprises: (i) 2.5-23 mg of donepezil or a pharma- ceutically acceptable salt thereof; and (ii) 0.1-2.5 mg of tadalafil or a pharma- ceutically acceptable salt thereof.

4. The composition of claim 1 which is a pharmaceutical composition or a food composition.

5. (i) donepezil or a pharma- ceutically acceptable salt thereof; and (ii) tadalafil or a pharma- ceutically acceptable salt thereof Including, the weight ratio of (i) donepezil or a pharma- ceutical acceptable salt thereof to (ii) tadalafil or a pharma-ceutical acceptable salt thereof is 5:1 to 20:1; Composition for improving cognitive function.

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