Potassium urate solid dispersion

Abstract

The present invention relates to a solid dispersion comprising an alkali metal salt of ursolic acid and a phospholipid, and an oral dosage form comprising the same. The present invention also relates to a method for preparing the solid dispersion, and the use of the solid dispersion and the dosage form for the prevention and / or treatment of various pathological conditions in which hepatoprotective, antioxidant, anti-inflammatory, antiviral, and cytotoxic activity are desired.

Description

Background Art

[0001] Formula (1):

[0002]

Chem.

[0003] The use of polymeric nanoparticle systems to improve bioavailability, even if achievable, would only be suitable for pharmaceuticals and not for products intended for the nutraceutical market (Current medicinal chemistry 2017, 24, 1-10).

[0004] This disadvantage also accompanies other formulation approaches existing in the prior art, such as the nanoparticles of ursolic acid reported by Zhou et al. (Drug Development and Industrial Pharmacy 2009 35(3) 305); the preparation containing ursolic acid, soybean phospholipids and poloxamer 188 and administrable by injection is preferably an orally administrable formulation, and its use in the field of dietary supplements is difficult.

[0005] According to Wu W. et al. (Journal of Solution Chemistry 27(6):521-531, 1998), since the thermodynamic solubility also depends on the crystal size, the use of nanocrystals enables a 2.56-fold increase in solubility compared to crude ursolic acid (J. Pi, et al. Current drug delivery (2016), 13(8), 1358-1366). However, due to the low fluidity of nanocrystals, formulation is difficult.

[0006] In contrast, the phospholipid complex of ursolic acid and lecithin disclosed in Chinese Patent Application No. 101095684 can be formulated into oral dosage forms such as capsules and tablets; however, the formation of the complex with lecithin leads to an improvement in bioavailability, but the acid-to-phospholipid ratio is 1:4 or more. This ratio means that the amount of the active substance in the complex is small, and it is necessary to prepare a high-dose pharmaceutical or dietary supplement formulation or to administer repeatedly.

[0007] Therefore, there is still a felt need for a simple and industrially sustainable method for increasing the solubility of ursolic acid.

[0008] [Description of the Invention] The applicant has now found that salts of orsellic acid with an alkali metal, such as potassium, can be dispersed in phospholipids to form a solid dispersion, and that such a dispersion [solid dispersion SD] is much more soluble in gastric juice compared to free orsellate salts, free orsellic acid, and also compared to a solid dispersion of orsellic acid with phospholipids (but lacking the alkali metal). Theoretically, this is very surprising since the solubility of hydrophilic or amphiphilic molecules such as salts of orsellic acid with an alkali metal would not be expected to benefit from being dispersed in a phospholipid matrix.

[0009] Accordingly, in one aspect, the present invention is a solid dispersion [solid dispersion SD] comprising: a) a salt of orsellic acid with an alkali metal, such as sodium and potassium, more preferably potassium, and b) a phospholipid and relates to a solid dispersion comprising the same.

[0010] According to a preferred aspect, the solid dispersion SD comprises one or more pharmaceutical or nutraceutical excipients [excipients (E)] suitable for modifying rheological properties, thereby enabling the production of oral pharmaceutical or nutraceutical formulations [formulations (F)].

[0011] Examples of excipients (E) are as follows: - Soluble and insoluble diluents such as cellulose, preferably microcrystalline cellulose, cellulose ethers, calcium phosphate, calcium carbonate, mannitol, maltodextrin, isomalt, and combinations thereof; - Lubricants and / or glidants such as silica, talc, stearic acid, magnesium stearate, and combinations thereof; - Surfactants such as sucrose esters, polysorbates, polyoxyethylene Chemicalization castor oil derivatives, D-α-tocopheryl polyethylene glycol succinate (vitamin E TPGS), and combinations thereof but are not limited thereto.

[0012] The foregoing and additional excipients are disclosed, for example, in Remington: “The Science and Practice of Pharmacy”, 22nd edition, Pharmaceutical Press, 2013 (the disclosure of which is incorporated herein by reference in its entirety as an example).

[0013] In an exemplary embodiment, the solid dispersion SD consists essentially of: a) a salt of ursolic acid with an alkali metal, preferably sodium and potassium, more preferably potassium; b) a phospholipid; c) cellulose or a cellulose ether or a combination thereof; and d) silica.

[0014] In embodiments of the specification that “consist essentially of” the recited components, such solid dispersions SD contain the recited components and components that do not substantially affect the basic and novel characteristics of the solid dispersion SD according to the claims. Components that do not substantially affect the basic and novel characteristics of the solid dispersion according to the claims are components that do not impair the solubility of the solid dispersion SD in gastric juice, compared to free ursolate, and compared to a solid dispersion of ursolic acid with a phospholipid (but lacking an alkali metal). Examples of components that do not substantially affect the basic and novel characteristics of the solid dispersion SD according to the claims and can thus be included in a solid dispersion SD that consists essentially of the recited components are various excipients such as soluble and insoluble diluents like cellulose, preferably microcrystalline cellulose, cellulose ethers, calcium phosphate, calcium carbonate, mannitol, maltodextrin, isomalt, and combinations thereof; lubricants and / or glidants such as silica, talc, stearic acid, magnesium stearate, and combinations thereof; surfactants such as sucrose esters, polysorbates, polyoxyethylene castor oil derivatives, D-α-tocopheryl polyethylene glycol succinate (vitamin E TPGS), and combinations thereof.

[0015] In a preferred embodiment, the solid dispersion SD consists of the following: e) salts of ursolic acid with alkali metals, preferably sodium and potassium, more preferably potassium; f) phospholipids; g) cellulose or cellulose ether or a combination thereof; h) silica.

[0016] Even more preferably, the dispersion SD consists of potassium ursolate, phospholipids, cellulose and silica.

[0017] In this description, the expression "ursolate" is intended to mean salts of ursolic acid with alkali metals and is intended to include the preferred salts and more preferred salts specified above.

[0018] Generally, when a term is used in its broadest sense in this specification, each narrower scope (preferred definition) is included unless otherwise specified.

[0019] The term "phospholipid" refers to a substance selected from one or more lecithins obtained from soybeans, sunflowers, eggs or any other plant or animal source and including phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine and mixtures thereof (wherein the acyl groups may be the same or different and can be derived from palmitic acid, stearic acid, oleic acid, linoleic acid or linolenic acid). According to a preferred embodiment, the phospholipid is soybean lecithin. According to another preferred embodiment, the phospholipid is sunflower lecithin.

[0020] As used herein, the terms "solid dispersion SD" or "SD" or "solid dispersion" indicate that the formulation contains a salt of ursolic acid with an alkali metal in an inert carrier (phospholipid) in a solid state prepared by a solvent method. The SD is deposited on the surface of microcrystalline cellulose or cellulose ether or a combination thereof.

[0021] The solid dispersion described in this specification appropriately does not contain any aqueous phase in which the solid state is suspended or dispersed, and specifically excludes liposomes, oil-in-water emulsions, and other aqueous dispersions.

[0022] The solid dispersion SD appropriately contains an oleanolic acid salt and a phospholipid with a weight ratio of 0.2:1 to 3:1 (0.3:1 to 3:1, 0.4:1 to 2:1, preferably 0.5:1 to 2:1, or 0.5:1 to 1:1, or including 1:1). The ratio indicating the mutual amount of the solid components is represented as a weight ratio unless otherwise specified. When a range is indicated, the ends of the range are included. In an exemplary embodiment, the amount of the oleanolic acid salt in the solid dispersion SD is 16% to 75% w / w (22% to 75%, 28% to 66%, preferably 33% to 66%, or 33% to 50%, or including 50%) by weight percentage.

[0023] The solid dispersion SD can be prepared by a process [Process (P1)] including the following: a-1) Mixing an oleanolic acid salt and a phospholipid in an alcohol, preferably a C 1 -C 3 aliphatic alcohol, more preferably ethanol, to provide a suspension; b-1) Heating the suspension obtained in step a-1) under reflux for 5 minutes to 5 hours, preferably 1 to 3 hours; c-1) Removing the solvent to provide the solid dispersion SD.

[0024] In step a-1), the oleanolic acid salt and the phospholipid are mixed at a weight ratio of 0.2:1 to 3:1, preferably 0.5:1 to 2:1. The alcohol is used in an amount of 10 to 20 volumes relative to the amount of the oleanolic acid salt. The selected oleanolic acid salt can optionally be prepared in situ by suspending oleanolic acid in the selected alcohol and adding a metal hydroxide. In particular, potassium oleanolate is prepared by suspending oleanolic acid in ethanol and then adding potassium hydroxide.

[0025] In step b-1), the heating is carried out at the reflux temperature of the selected alcohol.

[0026] In step c-1), most of the alcohol is usually removed by evaporation under reduced pressure to obtain a solid residue, which is an SD containing residual alcohol. Then, the residue is heated at a temperature of 30 °C to 70 °C, preferably 60 °C, under vacuum to completely remove the alcohol. Complete removal means that the amount of alcohol detected by GC (gas chromatography) is less than the ICH limit (i.e., 5000 ppm for ethanol).

[0027] Next, the obtained powder (dry SD) is pulverized to obtain a desired particle size typically in the range of 10 μm to 300 μm.

[0028] A solid dispersion SD further containing one or more excipients (E) can be prepared either by dry mixing the selected excipient with the dispersion obtained at the end of step c-1) and then pulverizing to the desired particle size, or by a process [process (P2)] which includes adding one or more excipients (E) during step a-1) above and optionally also at the end of step c-1).

[0029] Therefore, process (P2) includes the following steps: a-2) Mixing ursolate, phospholipid and excipient (E) in an alcohol, preferably a C 1 -C 3 aliphatic alcohol, more preferably ethanol, to provide a suspension; b-2) Heating the suspension obtained in step a-2) to reflux for 5 minutes to 5 hours, preferably 1 to 3 hours; c-2) Removing the solvent to obtain a solid, optionally adding a further excipient (E), and pulverizing to provide a solid dispersion SD.

[0030] In step a-2), the ursoic acid salt and the phospholipid are mixed at a weight ratio of 0.2:1 to 3:1, preferably 0.5:1 to 2:1. The solvent is used in an amount of 10 to 30 volumes relative to the amount of ursoic acid. Similar to process (P1), in process (P2) as well, the selected ursoic acid salt can optionally be prepared in situ by suspending ursoic acid in the selected alcohol and adding a metal hydroxide. In particular, potassium ursoate is prepared by suspending ursoic acid in ethanol and then adding potassium hydroxide.

[0031] In step a-2), the excipient (E) is used at a weight ratio of 0.1:1 to 1:2, preferably 0.5:1, relative to the ursoic acid salt.

[0032] In step b-2), the heating is carried out at the reflux temperature of the selected alcohol.

[0033] In step c-2), most of the alcohol is usually removed by evaporation under reduced pressure to obtain a solid residue, which is subjected to heating at a temperature of 30°C to 70°C, preferably 60°C, under vacuum to completely remove the residual alcohol. The resulting solid residue is then mixed with a further excipient (E) to provide a solid dispersion SD having a desired particle size, typically in the range of 10 μm to 300 μm. Any excipient (E) added after step c-2) is used in an amount of 0.01:1 to 0.1:1 relative to the solid residue obtained after complete solvent removal. Thus, the overall weight ratio of the excipient (E) to the ursoic acid salt can be in the range of 0.5:1 to 2:1.

[0034] In process (P2) for preparing a preferred solid dispersion SD consisting of an alkali metal salt of ursoic acid, a phospholipid, microcrystalline cellulose, and silica, the microcrystalline cellulose is added in step a-2), while the silica is added at the end of step c-2) before grinding.

[0035] As expected above, experiments conducted by the applicant have demonstrated that the solid dispersion SD of the present invention is much more soluble in artificial gastric juice compared to the solid dispersion of free ursolate, free ursolic acid, and ursolic acid containing phospholipids but lacking alkali metals. In fact, the simulation of gastrointestinal conditions is essential for appropriately predicting the in vivo behavior of the product and for reducing the scale and number of human tests required to identify pharmaceuticals with appropriate performance in both fed and fasted states (Klein, S.; AAPS Journal 2010, 12, 3, 397-406). The applicant used three different artificial gastric juices at three different pH values (pH 1.6, 6.5, and 5.0) to simulate the fasted state of the stomach, the fasted state of the intestine, and the fed state of the intestine, and observed the following: - The solubility of the solid dispersion SD at pH 1.6 was 0.5 - 0.3 mg / ml, which was approximately 6 - 13 times higher than the solubility of the solid dispersion of ursolic acid in the corresponding phospholipid; - The solubility of the solid dispersion SD at pH 6.5 was 1.1 - 1.2 mg / ml, which was approximately 2.5 - 2.8 times higher than the solubility of the solid dispersion of ursolic acid in the corresponding phospholipid; - The solubility of the solid dispersion SD at pH 5.0 was 0.8 - 1.1 mg / ml, which was 2 - 2.5 times higher than the solubility of the solid dispersion of ursolic acid in the corresponding phospholipid.

[0036] In view of its high solubility in artificial gastrointestinal fluids, the solid dispersion SD can be advantageously used to prepare an oral dosage form [formulation (F)]. Thus, a formulation (F) comprising the solid dispersion SD and further components such as pharmaceuticals or nutraceuticals is a further aspect of the present invention. Examples of formulation (F) include, but are not limited to, chewable tablets, capsules, soft gelatin capsules, hard gelatin capsules, lozenges, chewable lozenges, health bars, confectionery, animal feeds, cereals, cereal coatings, and combinations thereof. Formulation (F) can be prepared using methods and components known in the art, and they can be selected on a case-by-case basis by those skilled in the art according to specific needs. Non-limiting examples of such components include disintegrants, lubricants, binders, coating agents, colorants, absorption promoters, solubilizers, stabilizers, flavoring sweeteners, preservatives, storage agents, antioxidants, and the like.

[0037] The solid dispersion SD and formulation (F) of the present invention can be used for the prevention and / or treatment of Alzheimer's disease, Parkinson's disease, motor neuron disease, acute kidney injury, kidney disease, non-alcoholic fatty liver disease, type 2 diabetes, cardiovascular disease, muscular dystrophy, neuromuscular disorder, sarcopenia, and muscle atrophy disorder.

[0038] The present invention is disclosed in more detail in a non-limiting manner in the following experimental section.

[0039] Experimental section Materials Ursolic acid is commercially available from Sigma Aldrich. Microcrystalline cellulose (Avicel®) is available from DuPont. Silica (Syloid®) is available from Grace. Artificial gastric juices FaSSGF pH1.6, FaSSIF pH6.5 and FaSSIF pH5.5 are commercially available from BioRelevant. Potassium ursolate was prepared from ursolic acid by standard procedures. Method Analysis of the solid dispersion and measurement of its solubility in simulated gastric and intestinal fluids were carried out by HPLC using the equipment and conditions reported below. Column Stationary phase: Symmetry C18. Size: l = 250 mm; I.D. = 4.6 mm, particle size 5 μm. Manufacturer: Waters; P / N: WAT054275. Mobile phase Solvent A: 0.01% (V / V) formic acid in water Solvent B: 0.01% (V / V) formic acid in acetonitrile Solvent C: Methanol Linear gradient

[0040] [Table 1]

[0041] Analysis conditions Flow rate: 1.0 ml / min Detection: 205 nm Injection volume: 10 μl Column temperature: 15 °C Autosampler temperature: 20 °C Runtime: 32 minutes

[0042] Preparation examples [Example 1]

[0043] (Example of the present invention) - Solid dispersion of potassium ursolate in phospholipid (in-situ preparation of potassium ursolate) Ursolic acid (2.5 g, purity 90%, 4.92 mmol) was suspended in ethanol (30 ml). First, a 4% w / w potassium hydroxide solution in ethanol (1.16 equivalents) was added to the resulting suspension, and then sunflower lecithin (5 g) was added. The mixture was heated under reflux for 15 minutes. The solvent was evaporated to dryness under reduced pressure to obtain a solid residue, which was dried under vacuum at 60 °C and then pulverized. 7.5 g of dry solid was obtained. [Example 2]

[0044] (Example of the Invention) - Solid dispersion of potassium ursolate in phospholipid, microcrystalline cellulose and silica (in-situ preparation of potassium ursolate) Ursolic acid (2.5 g, purity 90%, 4.92 mmol) was suspended in ethanol (30 ml). To the resulting suspension, a 4% w / w potassium hydroxide solution in ethanol (1.16 equivalents) was first added, followed by sunflower lecithin (3.75 g) and microcrystalline cellulose (1.25 g). The suspension was heated under reflux for 15 minutes, then the solvent was evaporated to dryness under reduced pressure to obtain a solid residue, which was dried at 60 °C under vacuum and then pulverized in the presence of silica (75 mg). Yield: 7.5 g of the title product.

Example 3

[0045] (Example of the Invention) - Solid dispersion of potassium ursolate in phospholipid, microcrystalline cellulose and silica Potassium ursolate (6.5 g, content rate 77%), sunflower lecithin (7.5 g) and microcrystalline cellulose (2.5 g) were suspended in ethanol and heated under reflux for 15 minutes. The solvent was evaporated to dryness under reduced pressure to obtain a solid residue, which was dried at 60 °C under vacuum and then pulverized in the presence of silica (0.16 g). 15 g of the title product was obtained.

Example 4

[0046] (Comparative Example) - Solid dispersion of ursolic acid with phospholipid (lacking alkali metal) Ursolic acid (0.5 g, content rate 94%) and sunflower lecithin (1.0 g) were suspended in ethanol and heated under reflux for 60 minutes. The solvent was evaporated to dryness under reduced pressure to obtain a solid residue, which was dried at 60 °C under vacuum and then pulverized. 1.5 g of the title product was obtained.

[0047] Dissolution test Test 1 - Dissolution of solid dispersion of potassium ursolate with phospholipid A solid dispersion (300 mg) of potassium ursolate with the phospholipid of Example 1 was suspended in a selected artificial gastrointestinal fluid (20 mL) and stirred at 25 °C for 2 hours. Stirring was stopped and the undissolved solid was decanted. The supernatant was filtered through a hydrophilic 0.2 μm PTFA filter and the content of ursolic acid was analyzed.

[0048] Test 5 - Dissolution of a solid dispersion of potassium ursolate formulated with microcrystalline cellulose and silica Using 300 mg of a solid dispersion of potassium ursolate with the phospholipid formulated with microcrystalline cellulose and silica of Example 3 instead of the dispersion of Example 1, the same procedure as in Test 1 was followed.

[0049] Test 2 (Comparative Example) - Dissolution of ursolic acid Using 100 mg of ursolic acid instead of the dispersion of Example 1, the same procedure as in Test 1 was followed.

[0050] Test 3 (Comparative Example) - Dissolution of potassium ursolate Using 100 mg of potassium ursolate instead of the dispersion of Example 1, the same procedure as in Test 1 was followed.

[0051] Test 4 (Comparative Example) - Dissolution of a solid dispersion of ursolic acid with phospholipid Using 300 mg of a solid dispersion of ursolic acid with phospholipid instead of the dispersion of Example 1, the same procedure as in Test 1 was followed.

[0052] The test results are reported in Table 1 below. As shown, the solid dispersion SD prepared using a salt of ursolic acid with an alkali metal and a phospholipid provided the highest dissolution of ursolic acid compared to the solid dispersion SD with the alkali metal alone and even the solid dispersion SD lacking the alkali metal.

[0053] [Table 2]

Claims

Solid dispersion comprising a salt of ursolic acid with potassium and a phospholipid, wherein the weight ratio of the ursolic acid salt to the phospholipid is in the range of 0.5:1 to 2:

1.

2. The following: - cellulose, cellulose ether, calcium phosphate, calcium carbonate, mannitol, maltodextrin, isomalt, and combinations thereof; - silica, talc, stearic acid, magnesium stearate, and combinations thereof; - sucrose esters, polysorbates, polyoxyethylated castor oil derivatives, D-α-tocopheryl polyethylene glycol succinate, and combinations thereof The solid dispersion according to claim 1, further comprising one or more excipients selected from the group consisting of.

3. The solid dispersion according to claim 2, wherein the weight ratio of the one or more excipients to the salt of ursolic acid is in the range of 0.5:1 to 2:

1.

4. The following: Salt of ursolic acid with potassium; Phospholipid; Cellulose or cellulose ether or a combination thereof; and Silica The solid dispersion according to claim 2 or 3, consisting essentially of.

5. The solid dispersion according to claim 4, consisting of a salt of ursolic acid with potassium, a phospholipid, cellulose or cellulose ether or a combination thereof, and silica.

6. The solid dispersion according to any one of claims 2 to 5, comprising a salt of ursolic acid with potassium, a phospholipid, cellulose, and silica.

7. The phospholipid is obtained from soybeans, sunflowers, eggs, or any other plant or animal source and comprises phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, and mixtures thereof (wherein the acyl groups may be the same or different and may be derived from palmitic acid, stearic acid, oleic acid, linoleic acid, or linolenic acid), and is a substance selected from one or more lecithins. The solid dispersion according to any one of claims 1 to 6.

8. The solid dispersion according to claim 7, wherein the phospholipid is soy lecithin or sunflower lecithin.

9. The solid dispersion according to any one of claims 1 to 8, having a particle size in the range of 10 μm to 300 μm.

10. A method for preparing the solid dispersion according to claim 1, comprising the following steps: a-1) Suspending the ursolic acid salt and the phospholipid in alcohol to provide a suspension; b-1) heating the suspension obtained in step a-1) under reflux for 5 minutes to 5 hours, preferably 1 to 3 hours; c-1) removing the solvent to provide a solid dispersion A method comprising the steps of:

11. A method for preparing a solid dispersion according to any one of claims 2 to 8, comprising the following steps: a-2) suspending the ursolic acid salt, phospholipid and excipient in the above ratios in alcohol to provide a suspension; b-2) heating the suspension obtained in step a-2) under reflux for 5 minutes to 5 hours, preferably 1 to 3 hours; c-2) removing the alcohol to obtain a solid, optionally adding a further excipient, and pulverizing to provide a solid dispersion A method comprising the steps of:

12. An oral dosage form comprising a solid dispersion according to any one of claims 1 to 9, mixed with a further component of pharmaceutical or nutraceutical grade.

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