Crystalline composite and method for producing same, and composition

Abstract

The purpose of the present invention is to provide a new crystalline composite of nicotinamide mononucleotide which is stable and is highly safe. This crystalline composite comprises nicotinamide mononucleotide and a phenylalanine-based compound, wherein the phenylalanine-based compound is L-phenylalanine and exhibits peaks at diffraction angles (2θ) of 19.7 ± 0.2°, 26.4 ± 0.2°, and 32.8 ± 0.2° in a powder X-ray diffraction pattern measured using a Cu-Kα ray as an X-ray source, or the phenylalanine-based compound is aspartame and exhibits peaks at diffraction angles (2θ) of 7.0 ± 0.2°, 10.7 ± 0.2°, 14.4 ± 0.2°, and 29.1 ± 0.2° in a powder X-ray diffraction pattern measured using a Cu-Kα ray as an X-ray source.

Description

Crystalline complex, method for producing the same, and composition

[0001] The present invention relates to novel crystalline complexes of nicotinamide mononucleotide, methods for making the crystalline complexes, and compositions containing the crystalline complexes.

[0002] Nicotinamide mononucleotide (NMN) is a type of biochemical substance naturally present in living organisms, and has recently attracted attention as a substance that may inhibit aging and extend healthy lifespan. Patent Document 1 discloses an amino acid salt of nicotinamide mononucleotide, and Patent Document 2 discloses a cocrystal of nicotinamide mononucleotide and an isonicotinoid.

[0003] JP 2021-524501 A JP 2023-001065 A

[0004] The amino acid salt of nicotinamide mononucleotide disclosed in Patent Document 1 is highly hygroscopic, possibly due to its crystalline structure, and therefore can be difficult to handle when used in foods, health foods, supplements, pharmaceuticals, etc. The cocrystal of nicotinamide mononucleotide and isonicotinoid disclosed in Patent Document 2 uses an isonicotinoid that is not listed in the Pharmaceutical Additives Standards or the Official Compendium of Food Additives and has not been used in food, and safety is not guaranteed when used in foods, health foods, supplements, pharmaceuticals, etc.

[0005] The present invention has been made in light of the above-mentioned circumstances, and aims to provide a novel crystalline complex of nicotinamide mononucleotide that is stable without deliquescence and highly safe, using ingredients that are commonly eaten.

[0006] As a result of extensive research to solve the above-mentioned problems, the present inventors discovered that nicotinamide mononucleotide can form a crystalline complex only with some compounds from among a large number of compounds, and that these some compounds are L-phenylalanine and aspartame, which are safe compounds that are commonly eaten, and that when these compounds form a crystalline complex, safety and stability can be improved, thereby completing the present invention.

[0007] That is, the gist of the present invention is as follows: [1] A crystalline complex of nicotinamide mononucleotide and a phenylalanine-based compound, wherein the phenylalanine-based compound is L-phenylalanine, and the crystalline complex has peaks at diffraction angles (2θ) of 19.7±0.2°, 26.4±0.2°, and 32.8±0.2° in a powder X-ray diffraction pattern measured using Cu-Kα radiation as an X-ray source, or the phenylalanine-based compound is aspartame, and the crystalline complex has peaks at diffraction angles (2θ) of 7.0±0.2°, 10.7±0.2°, 14.4±0.2°, and 29.1±0.2° in a powder X-ray diffraction pattern measured using Cu-Kα radiation as an X-ray source. [2] The crystalline complex according to [1], wherein the molar ratio of nicotinamide mononucleotide to the phenylalanine-based compound (nicotinamide mononucleotide:phenylalanine-based compound) in the crystalline complex is 1:0.7 to 1:1.3. [3] The crystalline complex according to [1] or [2], wherein the phenylalanine-based compound is L-phenylalanine, and wherein a powder X-ray diffraction pattern measured using Cu-Kα radiation as an X-ray source has at least one characteristic selected from the following (i) to (iii): (i) the peak intensity ratio at diffraction angles (2θ) of 19.7±0.2° and 26.4±0.2° (peak intensity at 26.4±0.2° / peak intensity at 19.7±0.2°) is 0.35 or more and 0.90 or less; (ii) the peak intensity ratio at diffraction angles (2θ) of 19.7±0.2° and 32.8±0.2° (peak intensity at 32.8±0.2° / peak intensity at 19.7±0.2°) is 0.10 or more and 0.60 or less; (iii) the peak intensity ratio at diffraction angles (2θ) of 26.4±0.2° and 32.8±0.2° (peak intensity at 32.8±0.2° / peak intensity at 26.4±0.2°) is 0.30 or more and 0.80 or less [4] The phenylalanine compound is aspartame, [1] or [2], wherein the crystalline complex has at least one characteristic selected from the following (a) to (f) in a powder X-ray diffraction pattern measured using Cu-Kα radiation as an X-ray source:(a) The peak intensity ratio at diffraction angles (2θ) of 10.7±0.2° and 7.0±0.2° (peak intensity at 7.0±0.2° / peak intensity at 10.7±0.2°) is 0.30 or more and 0.70 or less. (b) The peak intensity ratio at diffraction angles (2θ) of 10.7±0.2° and 14.4±0.2° (peak intensity at 14.4±0.2° / peak intensity at 10.7±0.2°) is 0.05 or more and 0.50 or less. (c) The peak intensity ratio at diffraction angles (2θ) of 10.7±0.2° and 29.1±0.2° (peak intensity at 29.1±0.2° / peak intensity at 10.7±0.2°) is 0.05 or more and 0.50 or less. (d) The peak intensity ratio at diffraction angles (2θ) of 7.0 ± 0.2 ° and 14.4 ± 0.2 ° (peak intensity at 14.4 ± 0.2 ° / peak intensity at 7.0 ± 0.2 °) is 0.30 or more and 0.80 or less. (e) The peak intensity ratio at diffraction angles (2θ) of 7.0 ± 0.2 ° and 29.1 ± 0.2 ° (peak intensity at 29.1 ± 0.2 ° / peak intensity at 7.0 ± 0.2 °) is 0.30 or more and 0.70 or less. (f) The peak intensity ratio at diffraction angles (2θ) of 14.4 ± 0.2 ° and 29.1 ± 0.2 ° (peak intensity at 29.1 ± 0.2 ° / peak intensity at 14.4 ± 0.2 °) is 0.50 or more and 1.05 or less. [5] A composition comprising the crystalline complex according to any one of [1] to [4]. [6] The method for producing a crystalline complex according to any one of [1] to [4], wherein a crystalline complex is precipitated from a mixed solution containing nicotinamide mononucleotide and a phenylalanine-based compound. [7] The method for producing a crystalline complex according to [6], wherein a crystalline complex of nicotinamide mononucleotide and a phenylalanine-based compound is precipitated from a mixed solvent of water and a water-miscible organic solvent. [8] The method for producing a crystalline complex according to [6] or [7], wherein the molar ratio of nicotinamide mononucleotide to the phenylalanine-based compound in the mixed solution (nicotinamide mononucleotide:phenylalanine-based compound) is 1:0.7 to 1:1.3. [9] The method for producing a crystalline complex according to [7], wherein the water-miscible organic solvent contains at least one selected from the group consisting of monohydric alcohols, ketones, and nitriles.

[10] The method for producing a crystalline complex according to [7] or [9], wherein the mixing ratio of water to the water-miscible organic solvent in the mixed solvent is 0.5 to 50 volumes by volume per volume of water.

[0008] According to the present invention, it is possible to provide a novel crystalline complex of nicotinamide mononucleotide that is safe and has excellent stability, and a method for producing the same.

[0009] Fig. 1 is a powder X-ray diffraction pattern of the crystals obtained in Example 1. Fig. 2 is a powder X-ray diffraction pattern of the crystals obtained in Example 2. Fig. 3 is a powder X-ray diffraction pattern of the crystals obtained in Example 3. Fig. 4 is a powder X-ray diffraction pattern of the crystals obtained in Example 4.

[0010] The crystalline complex of nicotinamide mononucleotide of the present invention is a complex with a phenylalanine-based compound that is safe and has a history of consumption, and can be characterized by powder X-ray diffraction (PXRD). Specifically, it is a crystalline complex of nicotinamide mononucleotide and L-phenylalanine that has peaks at diffraction angles (2θ) of 19.7±0.2°, 26.4±0.2°, and 32.8±0.2° in powder X-ray diffraction using Cu-Kα radiation, or a crystalline complex of nicotinamide mononucleotide and aspartame (N-(L-α-aspartyl)-L-phenylalanine 1-methyl ester) that has peaks at diffraction angles (2θ) of 7.0±0.2°, 10.7±0.2°, 14.4±0.2°, and 29.1±0.2° in powder X-ray diffraction using Cu-Kα radiation. The crystalline complex of the present invention is safe and has excellent stability, and therefore is easy to handle, making it advantageous for use in foods, health foods, supplements, pharmaceuticals, and the like.

[0011] In powder X-ray diffraction, the intensity of diffraction peaks may vary depending on the pretreatment method used during measurement, the sample setting method, etc. This is called orientation or preferred orientation. This effect can cause changes in the intensity of characteristic peaks and, ultimately, the intensity ratio with other peaks, resulting in the powder X-ray diffraction pattern appearing different. However, as long as the position of the characteristic peak, i.e., the position of the diffraction angle (2θ), is the same, even if there is a change in peak intensity, it is essentially within the scope of the present invention. In other words, when determining the identity of a crystal by powder X-ray diffraction, the similarity of the position of the diffraction angle (2θ) and the overall pattern is important. Furthermore, the diffraction angle (2θ) in powder X-ray diffraction generally has an acceptable error range of ±0.2°. If the baseline of the powder X-ray diffraction pattern is disturbed due to the influence of amorphous substances, etc., it is preferable to correct the baseline to eliminate the influence of amorphous substances, etc.

[0012] Taking the above influences into consideration, for example, the crystalline complex of nicotinamide mononucleotide and L-phenylalanine preferably has, in powder X-ray diffraction using Cu-Kα radiation, (i) a peak intensity ratio at diffraction angles (2θ) of 19.7±0.2° and 26.4±0.2° (peak intensity at 26.4±0.2° / peak intensity at 19.7±0.2°) of 0.35 or more and 0.90 or less, preferably 0.40 or more and 0.80 or less, and more preferably 0.45 or more and 0.70 or less, (ii) a peak intensity ratio at diffraction angles (2θ) of 19.7±0.2° and 32.8±0.2° (peak intensity at 32.8±0.2° / peak intensity at 19.7±0.2°) of 0.10 or more and 0.60 or less, preferably 0.15 or more and 0.50 or less, and more preferably 0.20 or more and 0.45 or less, (iii) The peak intensity ratio at diffraction angles (2θ) of 26.4±0.2° and 32.8±0.2° (peak intensity at 32.8±0.2° / peak intensity at 26.4±0.2°) is 0.30 or more and 0.80 or less, preferably 0.35 or more and 0.70 or less, more preferably 0.40 or more and 0.65 or less. More preferably, it has two characteristics selected from the above (i) to (iii), and even more preferably it has three characteristics selected from the above (i) to (iii).

[0013] Furthermore, taking the above influences into consideration, for example, the crystalline complex of nicotinamide mononucleotide and aspartame preferably has, in powder X-ray diffraction using Cu-Kα radiation, (a) a peak intensity ratio at diffraction angles (2θ) of 10.7±0.2° and 7.0±0.2° (peak intensity at 7.0±0.2° / peak intensity at 10.7±0.2°) of 0.30 or more and 0.70 or less, preferably 0.35 or more and 0.65 or less, and more preferably 0.40 or more and 0.60 or less, (b) a peak intensity ratio at diffraction angles (2θ) of 10.7±0.2° and 14.4±0.2° (peak intensity at 14.4±0.2° / peak intensity at 10.7±0.2°) of 0.05 or more and 0.50 or less, preferably 0.10 or more and 0.40 or less, and more preferably 0.15 or more and 0.35 or less, (c) the peak intensity ratio at diffraction angles (2θ) of 10.7±0.2° and 29.1±0.2° (peak intensity at 29.1±0.2° / peak intensity at 10.7±0.2°) is 0.05 or more and 0.50 or less, preferably 0.10 or more and 0.40 or less, and more preferably 0.15 or more and 0.35 or less, (d) the peak intensity ratio at diffraction angles (2θ) of 7.0±0.2° and 14.4±0.2° (peak intensity at 14.4±0.2° / peak intensity at 7.0±0.2°) is 0.30 or more and 0.80 or less, preferably 0.35 or more and 0.70 or less, and more preferably 0.40 or more and 0.65 or less, (e) the peak intensity ratio at diffraction angles (2θ) of 7.0±0.2° and 29.1±0.2° (peak intensity at 29.1±0.2° / peak intensity at 7.0±0.2°) is 0.30 or more and 0.70 or less, preferably 0.35 or more and 0.65 or less, and more preferably 0.40 or more and 0.60 or less; and (f) the peak intensity ratio at diffraction angles (2θ) of 14.4±0.2° and 29.1±0.2° (peak intensity at 29.1±0.2° / peak intensity at 14.4±0.2°) is 0.50 or more and 1.05 or less, preferably 0.60 or more and 1.00 or less, and more preferably 0.70 or more and 0.95 or less. More preferably, it has two or more characteristics selected from the above (a) to (f), even more preferably it has four or more characteristics selected from the above (a) to (f), and even more preferably it has six of the above (a) to (f).

[0014] In the crystalline complex, the molar ratio of nicotinamide mononucleotide to the phenylalanine compound (L-phenylalanine or aspartame) (nicotinamide mononucleotide:phenylalanine compound) is preferably 1:0.7 to 1:1.3, more preferably 1:0.75 to 1:1.2, and even more preferably 1:0.8 to 1:1.1. The molar ratio of nicotinamide mononucleotide to the phenylalanine compound in the crystalline complex can be calculated by measuring the content of nicotinamide mononucleotide in the crystalline complex using high performance liquid chromatography (HPLC).

[0015] The crystalline complex of the present invention has a unique crystal structure and is therefore stable to moisture and preferably also to heat. Therefore, when the crystalline complex of the present invention is used as a raw material, it does not deliquesce during the production process or storage, making it easy to handle. Furthermore, since the crystal structure is unlikely to change during the production process or storage, it is possible to produce products (foods, health foods, supplements, pharmaceuticals, etc.) that maintain the same quality.

[0016] The nicotinamide mononucleotide crystalline complex of the present invention can be produced, for example, by a method including the steps of preparing a mixed solution in which nicotinamide mononucleotide and a phenylalanine compound (L-phenylalanine or aspartame) are dissolved, and precipitating the crystalline complex from the mixed solution.

[0017] The solvent used in the mixed solution is preferably at least one selected from the group consisting of water and a water-miscible organic solvent, and may be a single solvent or a mixed solvent, but a mixed solvent is preferred. In the case of a single solvent, the solvent is preferably water, and in the case of a mixed solvent, the solvent is preferably a mixed solvent of water and a water-miscible organic solvent. A water-miscible organic solvent refers to an organic solvent that is miscible with water.

[0018] Examples of water-miscible organic solvents include monohydric alcohols such as methanol, ethanol, n-propanol, isopropanol, and n-butanol; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ethers such as tetrahydrofuran and 1,4-dioxane; nitriles such as acetonitrile and propionitrile; amides such as N,N-dimethylformamide; and sulfoxides such as dimethyl sulfoxide. These may be used alone or in combination of two or more. As water-miscible organic solvents, monohydric alcohols, ketones, and nitriles are preferred from the viewpoint of obtaining a crystalline composite having a desired crystal structure with high efficiency. C1-C5 monohydric alcohols, C3-C5 ketones, and C2-C5 nitriles are more preferred, C1-C4 monohydric alcohols, C3-C4 ketones, and C2-C4 nitriles are even more preferred, and acetonitrile is even more preferred. When two or more kinds of water-miscible organic solvents are used, the amount of nitriles (preferably acetonitrile) in the total amount of water-miscible organic solvents is preferably 50 mass% or more, more preferably 70 mass% or more, and even more preferably 80 mass% or more, and the upper limit is, for example, 99.9 mass%.

[0019] When the solvent used for the mixed solution is a mixed solvent of water and a water-miscible organic solvent, the mixing ratio of water to the water-miscible organic solvent (the total amount when two or more types are used) is preferably 0.5 volumes or more, more preferably 0.7 volumes or more, and even more preferably 0.9 volumes or more of the water-miscible organic solvent per volume of water, from the viewpoint of highly efficiently obtaining a crystalline composite having a desired crystal structure. There is no particular upper limit, but the ratio may be, for example, 50 volumes or less.

[0020] The amount (volume) of the solvent (preferably a mixed solvent of water and acetonitrile at a volume ratio of 1:1) used in the mixed solution is preferably 1 to 50 times (ml / mmol), more preferably 2 to 40 times (ml / mmol), and even more preferably 2.5 to 30 times (ml / mmol) the molar amount of nicotinamide mononucleotide, from the viewpoint of highly efficiently obtaining a crystalline complex having a desired crystal structure.

[0021] The molar ratio of nicotinamide mononucleotide to the phenylalanine compound in the mixed solution (nicotinamide mononucleotide:phenylalanine compound) is preferably 1:0.7 to 1:1.3, more preferably 1:0.75 to 1:1.2, and even more preferably 1:0.8 to 1:1.1, from the viewpoint of obtaining a crystalline complex having a desired crystal structure with high efficiency.

[0022] The mixing for preparing the mixed solution can be carried out using known or conventional devices and conditions.

[0023] The mixing temperature for preparing the mixed solution is preferably 10 to 80°C, more preferably 15 to 70°C, and even more preferably 20 to 60°C, from the viewpoint of efficiently obtaining a crystalline composite having a desired crystal structure.

[0024] The mixed solution may be prepared, for example, by: (A) dissolving nicotinamide mononucleotide and a phenylalanine compound in water, followed by adding a water-miscible organic solvent; or (B) adding nicotinamide mononucleotide and a phenylalanine compound to a mixed solvent of water and a water-miscible organic solvent to create a supersaturated state.

[0025] Specifically, preparation procedure (A) preferably involves first dissolving nicotinamide mononucleotide and a phenylalanine compound in water at a volume 1 to 50 times (ml / mmol), preferably 5 to 30 times (ml / mmol) the molar amount of nicotinamide mononucleotide, and then gently adding a water-miscible organic solvent to the solution and mixing. The gentle addition preferably refers to dropwise addition over a period of 10 minutes or more. The addition time of the water-miscible organic solvent is preferably 10 to 200 minutes, more preferably 20 to 180 minutes, and even more preferably 30 to 150 minutes.

[0026] Specifically, preparation procedure (B) preferably involves first adding nicotinamide mononucleotide in an amount exceeding its saturated solubility to a mixed solvent of water and a water-miscible organic solvent, dissolving the nicotinamide mononucleotide, and then removing the residual solution. Then, to the resulting solution, an amount of a phenylalanine compound exceeding its saturated solubility is added, dissolving the phenylalanine compound, and then removing the residual solution to obtain a saturated solution. A more preferred mixed solution is one in which nicotinamide mononucleotide and a phenylalanine compound are further added to the saturated solution. When nicotinamide mononucleotide and a phenylalanine compound are further added to the saturated solution, the amount (molar amount) of nicotinamide mononucleotide added to the saturated solution is preferably 0.01 to 5 times (mmol / ml), more preferably 0.03 to 2 times (mmol / ml), and even more preferably 0.05 to 1 times (mmol / ml) the volume of water in the mixed solvent. When nicotinamide mononucleotide and a phenylalanine compound are further added to the saturated solution, the molar ratio of the amounts of nicotinamide mononucleotide and the phenylalanine compound added to the saturated solution (nicotinamide mononucleotide:phenylalanine compound) is preferably 1:0.7 to 1:1.3, more preferably 1:0.75 to 1:1.2, and even more preferably 1:0.8 to 1:1.1.

[0027] If necessary, auxiliary components such as antioxidants, ultraviolet absorbers, stabilizers, etc. may be added to the mixed solution within the range that does not interfere with the formation of the crystalline complex.

[0028] In the step of precipitating the crystalline composite from the mixed solution, when the solvent of the mixed solution is a single solvent, crystallization is performed by cooling the mixed solution. When the solvent of the mixed solution is water and a water-miscible organic solvent, the water-miscible organic solvent acts as a poor solvent, so crystallization is possible without cooling. However, cooling the mixed solution is preferred from the viewpoint of obtaining a crystalline composite with a desired crystal structure with high efficiency.

[0029] The cooling temperature of the mixed solution in the precipitation step of the crystalline composite is preferably higher than 0° C. and not higher than 20° C., more preferably 2° C. to 15° C., and even more preferably 3° C. to 12° C. Note that a cooling temperature of 0° C. or lower, at which the mixed solution freezes, is not preferred because it makes it impossible to obtain the desired crystalline structure of the crystalline composite.

[0030] The cooling time of the mixed solution in the crystalline composite precipitating step is preferably 0.5 to 96 hours, more preferably 1 to 72 hours, and even more preferably 3 to 60 hours.

[0031] When cooling the mixed solution in the step of precipitating the crystalline composite, the mixed solution may be stirred using known or conventional devices and conditions, but it is also preferable to allow the mixed solution to stand.

[0032] The precipitated crystalline composite may be separated from the solvent by solid-liquid separation. Examples of solid-liquid separation methods include natural filtration, vacuum filtration, pressure filtration, and centrifugal filtration. The crystalline composite obtained by solid-liquid separation may be further subjected to treatments such as washing, recrystallization, and drying using known or conventional equipment and conditions.

[0033] The yield of the crystalline complex obtained by the production method of the present invention is preferably 5 mol% or more, more preferably 10 mol% or more, based on nicotinamide mononucleotide, and there is no particular upper limit, and it may be 100 mol%.

[0034] The crystalline complex of the present invention can be used as a composition further containing other components depending on the application. The composition of the present invention has safety and excellent stability derived from the crystalline complex contained therein.

[0035] Examples of other ingredients include pharmaceutical ingredients, food ingredients, etc., and these ingredients can be contained in the composition in known combinations and blending ratios.

[0036] This application claims the benefit of priority based on Japanese Patent Application No. 2023-107092, filed on June 29, 2023. The entire contents of the specification of Japanese Patent Application No. 2023-107092, filed on June 29, 2023, are incorporated herein by reference.

[0037] The present invention will be explained in more detail below with reference to examples. However, the present invention is not limited to the following examples, and it is of course possible to carry out the invention by making appropriate modifications within the scope of the above and below-described aims, and all such modifications are included in the technical scope of the present invention.

[0038] The structure of the crystalline complex was identified by measuring the X-ray diffraction pattern of the sample using powder X-ray diffraction. The conditions for powder X-ray measurement are as follows: Apparatus: Rigaku Mini Flex II X-ray used: Cu-Kα ray Intensity: 30 kV, 15 mA Angle: 2θ = 2 to 60° Scanning speed: 2° / min Divergence slit (DS): 1.25° Scatter slit (SS): 1.25° Receiving slit (RS): 0.3 mm

[0039] The content of nicotinamide mononucleotide was measured by high performance liquid chromatography (HPLC). The HPLC conditions were as follows: Column: COSMOSIL 3PBr 3.0 x 150 mm (Nacalai Tesque) Column temperature: 40°C Mobile phase: 20 mM ammonium formate / MeOH = 95 / 5 Flow rate: 0.4 mL / min Detector: UV 260 nm Sample injection volume: 5 μL (in water)

[0040] Example 1: 6.7 g (20 mmol) of nicotinamide mononucleotide and 3.4 g (20 mmol) of L-phenylalanine were dissolved in 200 mL of water at 55°C. 200 mL of acetonitrile was added dropwise over 100 minutes, and the mixture was cooled to 4°C at 3°C / hr. The resulting slurry was evaporated to dryness under reduced pressure using a vacuum pump at 30°C, washed with acetonitrile, filtered, and dried to yield 1.23 g of white crystals. Powder X-ray diffraction analysis of the resulting crystals revealed unique peaks at 2θ (±0.2°) = 19.68°, 26.35°, and 32.70° that were not observed in the raw materials, nicotinamide mononucleotide and L-phenylalanine, confirming the formation of a crystalline complex with a different crystal structure from the raw materials. Figure 1 shows the powder X-ray diffraction pattern of the crystals. The resulting crystalline complex maintained its crystalline structure without deliquescence even after being left at room temperature for 24 hours.

[0041] Example 2: 6.7 g (20 mmol) of nicotinamide mononucleotide and 3.4 g (20 mmol) of L-phenylalanine were dissolved in 200 mL of water at 55°C. 200 mL of acetonitrile was added dropwise over 113 minutes, and the mixture was cooled to 4°C at 3°C / hr. The resulting slurry was concentrated at 30°C under reduced pressure using a vacuum pump. 200 mL of acetonitrile was added once during the concentration, and the mixture was then concentrated again and dried. The resulting mixture was then washed with acetonitrile, filtered, and dried to yield 2.25 g of white crystals. Powder X-ray diffraction analysis of the resulting crystals revealed unique peaks at 2θ (±0.2°) = 19.79°, 26.49°, and 32.83°, which were not observed in the starting materials, nicotinamide mononucleotide and L-phenylalanine, as in Example 1. This confirmed the reproducible production of a crystalline complex with a crystal structure different from that of the starting materials. Figure 2 shows the powder X-ray diffraction pattern of the crystals. Furthermore, the obtained crystalline complex maintained its crystalline structure without deliquescence even after being left in a room environment for 24 hours.

[0042] Example 3: 6.7 g (20 mmol) of nicotinamide mononucleotide and 5.89 g (20 mmol) of aspartame were dissolved in 200 mL of water at 55°C. 200 mL of acetonitrile was added dropwise over 100 minutes, and the mixture was cooled to 4°C at 3°C / hr. The resulting slurry was concentrated under reduced pressure at 30°C, filtered, and dried to obtain 3.10 g of white crystals. Powder X-ray diffraction analysis of the resulting crystals revealed unique peaks at 2θ (±0.2°) = 7.05°, 10.70°, 14.44°, and 29.10° that were not observed in the raw materials, nicotinamide mononucleotide and aspartame, confirming the formation of a crystalline complex with a different crystal structure from the raw materials. Figure 3 shows the powder X-ray diffraction pattern of the crystals. The resulting crystalline complex maintained its crystalline structure without deliquescence even after being left at room temperature for 24 hours.

[0043] Example 4: 4.0 g of nicotinamide mononucleotide was thoroughly dissolved in 50 mL of a 1:1 mixture of acetonitrile and water at 25°C. The residue was filtered, and then 1.0 g of L-phenylalanine was added and thoroughly dissolved at 25°C. The residue was again filtered, and to the resulting solution (hereinafter referred to as the saturated solution), 1.67 g (5 mmol) of nicotinamide mononucleotide and 0.83 g (5 mmol) of L-phenylalanine were added. The mixture was cooled to 6°C at 3°C / hr and then maintained at the same temperature with stirring for 2 days. The resulting slurry was filtered and dried at 30°C under reduced pressure using a vacuum pump to obtain 2.16 g of white crystals. Powder X-ray diffraction analysis of the resulting crystals revealed unique peaks at 2θ (±0.2°) = 19.77°, 26.25°, and 32.95° that were not observed in the starting materials, nicotinamide mononucleotide and L-phenylalanine, confirming the formation of a crystalline complex with a crystal structure different from that of the starting materials. The powder X-ray diffraction pattern of the crystals is shown in Figure 4. The amount of nicotinamide mononucleotide contained in the crystals was measured by HPLC to be 55.4 mol%, suggesting that a crystalline complex with a nicotinamide mononucleotide:phenylalanine ratio of 1:0.8 had been formed. Furthermore, the obtained crystalline complex maintained its crystalline structure without deliquescence even after being left at room temperature for 24 hours.

[0044] ((Thermal Stability Test)) The crystalline complex obtained in Example 4 and, for comparison, nicotinamide mononucleotide powder were each heated at 150°C for 1 hour. The nicotinamide mononucleotide content before and after heating was measured by HPLC, and the thermal stability was examined based on the amount of nicotinamide mononucleotide remaining after heating relative to the amount before heating. As a result, the nicotinamide mononucleotide content of the nicotinamide mononucleotide powder was reduced to 81 mol% due to thermal decomposition, whereas the amount of nicotinamide mononucleotide remaining after heating in the crystalline complex obtained in Example 4 was 90 mol%, indicating that the thermal stability was improved by becoming a crystalline complex.

[0045] Comparative Example 1: 1 g (3 mmol) of nicotinamide mononucleotide and 0.5 g (3 mmol) of L-phenylalanine were added to a container containing 80 mL of water. The container was cooled to freeze the contents, then connected to a freeze dryer and freeze-dried to obtain a solid. The resulting solid was analyzed by powder X-ray diffraction. The X-ray diffraction pattern was different from the patterns of the crystals obtained in Examples 1, 2, and 4, and no peaks characteristic of the crystalline complex of the present invention were observed. Furthermore, only very weak diffraction peaks were observed, suggesting that the solid had low crystallinity. The resulting solid was hygroscopic, and after being left in a room environment, it immediately absorbed moisture and became sticky over time.

Claims

1. A crystalline complex of nicotinamide mononucleotide and a phenylalanine compound, wherein the phenylalanine compound is L-phenylalanine, and in a powder X-ray diffraction pattern measured using Cu-Kα radiation as an X-ray source, the complex has peaks at diffraction angles (2θ) of 19.7±0.2°, 26.4±0.2°, and 32.8±0.2°; or the phenylalanine compound is aspartame, and in a powder X-ray diffraction pattern measured using Cu-Kα radiation as an X-ray source, the complex has peaks at diffraction angles (2θ) of 7.0±0.2°, 10.7±0.2°, 14.4±0.2°, and 29.1±0.2°.

2. The crystalline complex according to claim 1, wherein the molar ratio of nicotinamide mononucleotide to the phenylalanine compound (nicotinamide mononucleotide:phenylalanine compound) in the crystalline complex is 1:0.7 to 1:1.

3.

3. The crystalline complex according to claim 1, wherein the phenylalanine compound is L-phenylalanine, and the crystalline complex has at least one characteristic selected from the following (i) to (iii) in a powder X-ray diffraction pattern measured using Cu-Kα radiation as an X-ray source: (i) the peak intensity ratio at diffraction angles (2θ) of 19.7±0.2° and 26.4±0.2° (peak intensity at 26.4±0.2° / peak intensity at 19.7±0.2°) is 0.35 or more and 0.90 or less; (ii) the peak intensity ratio at diffraction angles (2θ) of 19.7±0.2° and 32.8±0.2° (peak intensity at 32.8±0.2° / peak intensity at 19.7±0.2°) is 0.10 or more and 0.60 or less; (iii) the peak intensity ratio at diffraction angles (2θ) of 26.4±0.2° and 32.8±0.2° (peak intensity at 32.8±0.2° / peak intensity at 26.4±0.2°) is 0.30 or more and 0.80 or less.

4. The crystalline complex according to claim 1, wherein the phenylalanine compound is aspartame, and the crystalline complex has at least one characteristic selected from the following (a) to (f) in a powder X-ray diffraction pattern measured using Cu-Kα radiation as an X-ray source: (a) the peak intensity ratio at diffraction angles (2θ) of 10.7±0.2° and 7.0±0.2° (peak intensity at 7.0±0.2° / peak intensity at 10.7±0.2°) is 0.30 or more and 0.70 or less; (b) the peak intensity ratio at diffraction angles (2θ) of 10.7±0.2° and 14.4±0.2° (peak intensity at 14.4±0.2° / peak intensity at 10.7±0.2°) is 0.05 or more and 0.50 or less; (c) the peak intensity ratio at diffraction angles (2θ) of 10.7±0.2° and 29.1±0.2° (peak intensity at 29.1±0.2° / peak intensity at 10.7±0.2°) is 0.05 or more and 0.50 or less. (d) the peak intensity ratio at diffraction angles (2θ) of 7.0±0.2° and 14.4±0.2° (peak intensity at 14.4±0.2° / peak intensity at 7.0±0.2°) is 0.30 or more and 0.80 or less; (e) the peak intensity ratio at diffraction angles (2θ) of 7.0±0.2° and 29.1±0.2° (peak intensity at 29.1±0.2° / peak intensity at 7.0±0.2°) is 0.30 or more and 0.70 or less; (f) the peak intensity ratio at diffraction angles (2θ) of 14.4±0.2° and 29.1±0.2° (peak intensity at 29.1±0.2° / peak intensity at 14.4±0.2°) is 0.50 or more and 1.05 or less.

5. A composition comprising the crystalline complex of claim 1 or 2.

6. A method for producing the crystalline complex according to claim 1 or 2, which comprises precipitating the crystalline complex from a mixed solution in which nicotinamide mononucleotide and a phenylalanine compound are dissolved.

7. The method according to claim 6, wherein the crystalline complex of nicotinamide mononucleotide and a phenylalanine compound is precipitated from a mixed solvent of water and a water-miscible organic solvent.

8. The method according to claim 6, wherein the molar ratio of nicotinamide mononucleotide to the phenylalanine compound in the mixed solution (nicotinamide mononucleotide:phenylalanine compound) is 1:0.7 to 1:1.

3.

9. The method according to claim 7, wherein the water-miscible organic solvent comprises at least one member selected from the group consisting of monohydric alcohols, ketones, and nitriles.

10. The method according to claim 7, wherein the mixing ratio of water to the water-miscible organic solvent in the mixed solvent is 0.5 to 50 volumes of the water-miscible organic solvent per volume of water.