Crystals of reduced coenzyme Q10 and method for producing the same

Abstract

This invention provides crystals of reduced coenzyme Q10 that exhibit an endothermic peak at 52±2°C when measured by differential scanning calorimetry with a heating rate of 10 kJ / min. Compared to conventional techniques, the crystals of reduced coenzyme Q10 according to this invention are more stable and exhibit superior physical properties such as water solubility and residual solvent. Furthermore, the crystalline form according to this invention overcomes the drawbacks of conventional reduced coenzyme Q10, such as its high susceptibility to oxidation and limitations in use. Moreover, the crystals of reduced coenzyme Q10 and crystalline solids containing these crystals according to this invention not only exhibit superior stability but also high purity and low solvent residue.

Description

[Technical Field]

[0001] This application claims priority to Chinese Patent Application No. 202311751931.0, filed with the China National Intellectual Property Office on 19 December 2023, entitled “Crystals of Reduced Coenzyme Q10 and Method for Producing the Same,” the entirety of which is incorporated herein by reference.

[0002] The present invention belongs to the field of composite crystal technology, and more particularly to crystals of reduced coenzyme Q10 and a method for producing the same. [Background technology]

[0003] Coenzyme Q10 (chemical name: 2,3-dimethoxy-5-methyl-6-decaprenylbenzoquinone), also known as ubiquinone 10, has a structure similar to vitamin K. It was discovered and its chemical structure confirmed by scientists in the mid-20th century. Coenzyme Q10 is a widely distributed, lipid-soluble organoquinone compound and a type of vitamin-like compound with important physiological and pharmacological effects. In the early 1980s, Ernst of Sweden demonstrated that the vitamin-like substance coenzyme Q10 has antioxidant and free radical scavenging properties. In 1972, Harman explained the relationship between mitochondrial function and aging. Coenzyme Q10 primarily binds to the mitochondrial membrane and, as a coenzyme in the respiratory chain pathway, plays a role in hydrogen transfer in energy metabolism within the body. Coenzyme Q10 is a metabolic activator; it can activate cellular respiration, provide cellular power, and promote adenosine triphosphate (ATP) production. Furthermore, coenzyme Q10 itself is a natural antioxidant produced by cells, and can suppress mitochondrial peroxidation and protect the structural integrity of biological membranes. As a non-vitamin nutrient, it activates cellular respiration after meals, promotes the production of high-energy ATP, strengthens myocardial metabolic function, increases cardiac efficiency, regulates hypoxic states in cells and tissues, and has beneficial protective and ameliorative effects on the liver, brain, heart, and nervous system. Coenzyme Q10 has a highly specific immune-enhancing effect, increasing the phagocytic rate of phagocytic cells and increasing antibody production. Numerous clinical studies both domestically and internationally have shown extremely good therapeutic effects on diseases such as heart disease, hypertension, cerebrovascular disorders, scurvy, and viral hepatitis, suggesting that it functions as a nonspecific immune enhancer, cellular metabolism promoter, and cellular respiration activator. More recently, it has also been discovered to show remarkable adjuvant therapeutic effects against cancer and acquired immunodeficiency syndrome (AIDS). Therefore, coenzyme Q10 plays an invaluable role in managing health, slowing aging, and boosting immunity, and has great potential for a wide range of applications. Furthermore, because coenzyme Q10 has no toxicity or side effects and does not interact with other drugs, it has become an important pharmaceutical and healthcare product.

[0004] Most coenzyme Q10 currently on the market is oxidized coenzyme Q10. However, research has revealed that reduced coenzyme Q10, which has two electrons relative to oxidized coenzyme Q10, has higher oral absorption than oxidized coenzyme Q10, and that reduced coenzyme Q10 plays the primary role in the body. The only difference between the two is that one exists in the form of benzoquinone, and the other in the form of benzene glycol.

[0005] Furthermore, in many currently published technical documents concerning the production of reduced coenzyme Q10, with the exception of extraction from fermentation liquid (most of which is reduced coenzyme Q10 during fermentation, but is gradually oxidized to oxidized coenzyme Q10 during extraction), methods often employ oxidized coenzyme Q10 as a raw material and reduction to reduced coenzyme Q10 using conventional reducing agents. Examples of such reducing agents include sodium borohydride, sodium dithionite, ascorbic acid, and several specific amino acids, while the solvents used are mainly aliphatic hydrocarbons and fatty acid esters. In addition, several methods are known for producing reduced coenzyme Q10 in crystalline form, such as crystallizing reduced coenzyme Q10 in an alcohol solution and / or ketone solution (WO2003 / 006409) and crystallizing by adding a high-concentration liquid phase of reduced coenzyme Q10 to a poor solvent (Japanese Patent Publication No. 2003-089669).

[0006] On the other hand, patent document (WO2012 / 176842) describes the observation of crystalline polymorphism in reduced coenzyme Q10 and the acquisition of a new crystalline form different from that described in the above document. It reports that this newly discovered crystalline form is extremely stable and has superior other physical properties compared to conventional reduced coenzyme Q10, and also discloses its manufacturing method. Compared to conventional reduced coenzyme Q10 (hereinafter referred to as type I reduced coenzyme Q10 crystal or type I crystal), this newly discovered crystalline form (hereinafter referred to as type II reduced coenzyme Q10 crystal or type II crystal) is reported to be extremely stable and has superior other physical properties.

[0007] However, due to its structure, just as reduced coenzyme Q10, the main component in the fermentation liquid during fermentation, gradually becomes oxidized coenzyme Q10 during the extraction process, reduced coenzyme Q10 during chemical manufacturing is also oxidized by oxygen in the air to become oxidized coenzyme Q10. Since it is extremely difficult to completely remove oxygen molecules on a commercial scale, the adverse effects of residual oxygen during the manufacturing process are significant, potentially leading to the generation of oxidized coenzyme Q10 that is virtually impossible to remove, and its contamination of the product may reduce its purity. Furthermore, research has shown that although the product is stable in the solvent, it is easily oxidized during filtration, drying, and storage. To obtain high-purity reduced coenzyme Q10 in crystalline form, it is important to adequately protect the reduced coenzyme Q10 from the aforementioned oxidative processes.

[0008] Furthermore, while conventional literature states that the crystal form significantly affects the oxidation rate, research has shown that the crystal forms obtained in various examples of conventional technical literature (WO2012 / 176842, Type II) were actually Type I, not Type II as reported in the conventional literature, as measured by powder X-ray diffraction. While some literature reports encapsulation with oil or the addition of antioxidants, introducing new substances may adversely affect the product. Additionally, when purifying with aliphatic hydrocarbon solvents such as n-hexane or n-heptane (excluding ethanol), solvent residue may remain, failing to meet the requirements. Moreover, increasing the drying temperature may lead to frequent liquefaction, as the melting point of oxidized or reduced coenzyme Q10 is approximately 50°C. When crystallization is performed using ethanol, the resulting product is prone to discoloration, is yellow in appearance, and is obtained in a slurry form, making filtration difficult. [Overview of the project] [Problems that the invention aims to solve]

[0009] Therefore, the technical problem that the present invention aims to solve is to provide a crystal of reduced coenzyme Q10 having relatively high stability and purity, and a method for producing the same. [Means for solving the problem]

[0010] This invention provides crystals of reduced coenzyme Q10 that have an endothermic peak at 52±2℃ when measured by differential scanning calorimetry with a heating rate of 10k / min.

[0011] Preferably, the powder X-ray diffraction pattern obtained by measurement using Cu-Kα rays shows characteristic peaks at diffraction angles (2θ±0.2°) of 8.95°, 10.04°, 15.09°, 18.65°, 19.03°, 21.61°, and 23.01°.

[0012] Preferably, the crystals of the reduced coenzyme Q10 have an infrared absorption spectrum obtained by the KBr tablet method with a wavenumber of 794 ± 1 cm⁻¹. -1 , 877±1cm -1 , 962cm -1 and 1014cm -1 It has a characteristic absorption peak.

[0013] Preferably, it has a powder X-ray diffraction pattern by the Cu-Kα method as shown in Figure 1, and / or, having an infrared absorption spectrum obtained by the KBr tablet method shown in Figure 2, And / or, it has the differential scanning calorimetry curve shown in Figure 3.

[0014] The present invention also provides a method for producing crystals of reduced coenzyme Q10, which includes the step of crystallizing reduced coenzyme Q10 in the presence of a cyclic ether solvent, a fluorine-containing alcohol solvent, and an organic base to obtain crystals of reduced coenzyme Q10.

[0015] Preferably, the step specifically comprises: mixing and dissolving reduced coenzyme Q10 and a cyclic ether solvent under heating conditions, adding a mixed solution of a fluorine-containing alcohol solvent and an organic base, cooling the mixture to allow crystallization at a crystallization temperature of 0°C to 20°C, thereby obtaining crystals of reduced coenzyme Q10.

[0016] Preferably, the cyclic ether solvent is one or more selected from the group consisting of 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, tetrahydrofuran and 2,5-dimethyltetrahydrofuran, the fluorine-containing alcohol solvent is one or more selected from the group consisting of trifluoromethanol, trifluoroethanol, trifluoropropanol and trifluorobutanol, and the organic base is one or more selected from the group consisting of triethylamine, pyridine and piperidine.

[0017] Preferably, the ratio of the reduced coenzyme Q10 to the cyclic ether solvent is 1 g:(1 to 10) mL, the volume ratio of the cyclic ether solvent to the fluorine-containing alcohol solvent is 1:(1 to 10), and the mass of the organic base is 0.1% to 10% relative to the mass of the reduced coenzyme Q10.

[0018] The present invention also provides a crystalline solid of reduced coenzyme Q10, which comprises the crystals of reduced coenzyme Q10 described above.

[0019] The present invention also provides a reduced coenzyme Q10 composition, which comprises the crystals of reduced coenzyme Q10 described above and / or the crystalline solid of reduced coenzyme Q10 described above.

[0020] According to the present invention, there is provided a crystal of reduced coenzyme Q10 that has an endothermic peak at 52±2°C when measured by differential scanning calorimetry with a temperature increase rate of 10°C / min. Compared with conventional techniques, the crystalline form of reduced coenzyme Q10 according to the present invention has higher stability than crystals of reduced coenzyme Q10 reported in conventional documents, and is also excellent in other physical properties such as water solubility and residual solvent content. Furthermore, according to the crystal form of the present invention, the drawbacks of conventional reduced coenzyme Q10, which is extremely easily oxidized and has restrictions in use, are overcome. Furthermore, the crystal of reduced coenzyme Q10 according to the present invention and the crystalline solid containing said crystal are not only excellent in stability, but also excellent in high purity and low residual solvent content. [Brief Description of the Drawings]

[0021] [Figure 1] It is a powder X-ray diffraction pattern of the crystal of reduced coenzyme Q10 obtained in Example 1 of the present invention. [Figure 2] It is an infrared absorption spectrum of the crystal of reduced coenzyme Q10 obtained in Example 1 of the present invention. [Figure 3] It is a DSC curve of the crystal of reduced coenzyme Q10 obtained in Example 1 of the present invention. [Figure 4] It is a powder X-ray diffraction pattern of the crystal of reduced coenzyme Q10 obtained in Comparative Example 1 of the present invention. [Figure 5] It is an HPLC chromatogram of the crystal of reduced coenzyme Q10 obtained in Example 1 of the present invention after storage for 360 days. [Figure 6] It is an HPLC chromatogram of the crystal of reduced coenzyme Q10 obtained in Comparative Example 1 of the present invention after storage for 360 days. [Figure 7] It is an HPLC chromatogram of the crystal of reduced coenzyme Q10 obtained in Example 1 of the present invention. [Figure 8] It is an HPLC chromatogram of the crystal of reduced coenzyme Q10 obtained in Comparative Example 1 of the present invention. [Mode for Carrying Out the Invention]

[0022] The technical methods in embodiments of the present invention will be described clearly and completely below with reference to the embodiments of the present invention. It will be clear that the embodiments described herein are only a selection of embodiments of the present invention, not all embodiments. All other embodiments that a person skilled in the art can obtain based on the embodiments of the present invention without expediency are included within the scope of the present invention.

[0023] The present invention provides a crystal of reduced coenzyme Q10 having a novel crystalline form that is clearly different in physical and chemical properties and crystalline structure from the crystals of reduced coenzyme Q10 reported in the prior art literature.

[0024] Specifically, the present invention provides crystals of reduced coenzyme Q10 that, when measured by differential scanning calorimetry at a rate of 10 kJ / min, have an endothermic peak at 52 ± 2°C, and more specifically, have an endothermic peak at 52 ± 2°C indicating crystal melting.

[0025] More specifically, the crystal of the reduced coenzyme Q10 has the differential scanning calorimetry curve shown in Figure 3.

[0026] The crystals of the reduced coenzyme Q10 according to the present invention preferably show characteristic peaks at diffraction angles (2θ±0.2°) 8.95°, 10.04°, 15.09°, 18.65°, 19.03°, 21.61° and 23.01° in the powder X-ray diffraction pattern obtained by measurement using Cu-Kα rays, and in particular show strong characteristic diffraction peaks at diffraction angles (2θ±0.2°) 8.95°, 19.03° and 23.01°.

[0027] More specifically, the crystal of the reduced coenzyme Q10 has a powder X-ray diffraction pattern obtained by measurement using Cu-Kα radiation as shown in Figure 1. The XRD diffraction pattern shown in Figure 1 has a characteristic peak that is completely different from the diffraction pattern of crystals reported in conventional literature (CN103635452A), so it is clear that the crystal of the reduced coenzyme Q10 of the present invention shown in Figure 1 is a novel crystal polymorph of reduced coenzyme Q10.

[0028] and / or, more specifically, the crystal of reduced coenzyme Q10, in an infrared absorption spectrum measured by the KBr tablet method, has 794±1 cm -1 , 877±1 cm -1 , 962 cm -1 and 1014 cm -1 characteristic absorption peaks. In the above infrared absorption spectrum, the peaks near 794±1 cm -1 and 877±1 cm -1 are characteristic absorption peaks consisting of two peaks of comparable intensity, and the peaks near 962 cm -1 and 1014 cm -1 are characteristic absorption peaks consisting of two peaks of substantially comparable intensity. Since crystals of reduced coenzyme Q10 reported in conventional literature do not have two absorption peaks at these positions, it has been revealed that the crystal of reduced coenzyme Q10 according to the present invention is a novel crystal form of reduced coenzyme Q10 that is different from the crystal forms reported in conventional literature.

[0029] Still more specifically, the crystal of reduced coenzyme Q10 according to the present invention has an infrared absorption spectrum measured by the KBr tablet method as shown in Figure 2.

[0030] In the present invention, when the crystal of reduced coenzyme Q10 exhibits at least one of the above DSC endothermic peak, XRD diffraction pattern and IR absorption pattern, it is a novel crystal of reduced coenzyme Q10 according to the present invention.

[0031] According to the present invention, the crystals of reduced coenzyme Q10 have good water solubility. The solubility of the crystals of reduced coenzyme Q10 in purified water at a temperature of 25°C is preferably 0.01 wt% or more, more preferably 0.1 wt% or more, and even more preferably 0.5 wt% or more. The solubility of the crystals of reduced coenzyme Q10 according to the present invention is significantly higher than the solubility (0.001 wt% or less) shown by conventionally known crystals of reduced coenzyme Q10. As described above, the crystals of reduced coenzyme Q10 according to the present invention have a higher melting point and superior solubility in water compared to crystals of reduced coenzyme Q10 reported in conventional literature. Therefore, they are not only structurally different crystal forms from those of reduced coenzyme Q10 reported in conventional literature, i.e., novel crystal forms of reduced coenzyme Q10 (or crystals having this crystal form), but are also more stable crystals. The stable form of reduced coenzyme Q10 crystals according to the present invention has high thermal stability as well as high solubility in water.

[0032] The crystals of reduced coenzyme Q10 according to the present invention exhibit excellent stability against oxygen molecules. Conventionally, reduced coenzyme Q10 is known to be easily oxidized by oxygen molecules in the air. However, as shown in the examples described later, the novel crystalline form of reduced coenzyme Q10 discovered in the present invention and the crystals of reduced coenzyme Q10 mainly composed of it are more stable than the crystalline forms listed in the literature, even when exposed to air without any protective measures against oxygen. Furthermore, even when coexisting with crystals of reduced coenzyme Q10 reported in the conventional literature or other amorphous components, the crystalline polymorph of reduced coenzyme Q10 according to the present invention can exhibit high oxidative stability, and the crystalline solid of reduced coenzyme Q10 according to the present invention also exhibits oxidative stability not known from conventional knowledge. The oxidative stability of the reduced coenzyme Q10 crystals and crystalline solids according to the present invention cannot be generalized as it depends on the content of the novel reduced coenzyme Q10 crystal form in the crystals or crystalline solid and the storage conditions. However, for example, reduced coenzyme Q10 stored at 25°C in air and shielded from light for a predetermined period of time has a retention rate (%) of approximately 80% or more, preferably approximately 85% or more, more preferably approximately 90% or more, and particularly preferably 95% or more. The retention rate referred to here is the ratio value obtained by dividing the absolute content (or concentration in the crystalline solid) of reduced coenzyme Q10 stored for the predetermined period by the absolute content (or concentration in the crystalline solid) of reduced coenzyme Q10 in the composition before storage. The predetermined period is not particularly limited, but for example it is 6 months, preferably 12 months, and more preferably 36 months.

[0033] The crystalline form of reduced coenzyme Q10 according to the present invention is more stable than the crystals of reduced coenzyme Q10 reported in conventional literature, and also exhibits superior physical properties such as water solubility and residual solvent. Furthermore, the crystalline form according to the present invention overcomes the drawbacks of conventional reduced coenzyme Q10, which were that it was highly susceptible to oxidation and had limitations in use. Moreover, the crystals of reduced coenzyme Q10 according to the present invention and the crystalline solids containing these crystals not only exhibit superior stability but also superior purity and low solvent residue.

[0034] The present invention also provides a method for producing crystals of reduced coenzyme Q10, which includes the step of crystallizing reduced coenzyme Q10 in the presence of a cyclic ether solvent, a fluorine-containing alcohol solvent, and an organic base to obtain crystals of reduced coenzyme Q10.

[0035] In this invention, the supply of all raw materials is not particularly limited and any commercially available product is acceptable.

[0036] In the present invention, it is preferable to obtain crystals of reduced coenzyme Q10 by mixing and dissolving reduced coenzyme Q10 and a cyclic ether solvent under heating conditions, adding a mixed solution of a fluorine-containing alcohol solvent and an organic base, and then cooling to crystallize.

[0037] The reduced coenzyme Q10 in the present invention is not particularly limited as long as it is a reduced coenzyme Q10 known to those skilled in the art. The purity of the reduced coenzyme Q10 is preferably 99% or higher, and more preferably 99.5% or higher.

[0038] Regarding the solvents used during crystallization and subsequent processing, since reduced coenzyme Q10 is difficult to dissolve in alcohol solvents, recrystallization using alcohol as reported in conventional literature is not appropriate. Therefore, when alcohol is added as a poor solvent, the crystallization system tends to become slurryy, making filtration difficult, and the resulting crystal form remains the same as the crystal form initially reported in the literature. On the other hand, when a single fatty acid ester or ether is used as the solvent, the sample becomes more soluble, resulting in a low crystallization yield. Although the yield does not increase unless the solvent ratio or temperature is reduced, the system becomes relatively viscous and filtration difficult due to the temperature being too low or the solvent ratio being too low, and the resulting crystal form remains the same as that reported in conventional literature. Furthermore, when using alkanes such as n-hexane, n-heptane, n-propane, and n-butane, it was found that the product could be obtained in high yield by appropriately setting the crystallization temperature and the ratio of solvent to crude product. However, the resulting crystalline form was confirmed to be type I of reduced coenzyme Q10 as reported in conventional literature, and the amount of residual solvent after 48 hours of drying did not meet the requirements.

[0039] As a result of extensive research, the inventors have found that using a good solvent such as a cyclic ether, a poor solvent such as a fluorine-containing alcohol, and a small amount of organic base results in a higher yield, and the crystallized crystalline form is more stable than the crystalline form reported in conventional literature, and further impurities are removed.

[0040] Reduced coenzyme Q10 and a cyclic ether solvent are mixed and dissolved under heating conditions. The cyclic ether solvent is preferably one or more selected from the group consisting of 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, tetrahydrofuran, and 2,5-methyltetrahydrofuran. The ratio of reduced coenzyme Q10 to the cyclic ether solvent is preferably 1g:(1~10)mL, more preferably 1g:(1~8)mL, even more preferably 1g:(1~5)mL, and most preferably 1g:(1~3)mL. In some embodiments of the present invention, the ratio of reduced coenzyme Q10 to the cyclic ether solvent is specifically 1g:2mL or 1g:10mL. The mixing and dissolution temperature is preferably 30°C to 50°C, more preferably 35°C to 45°C, and even more preferably 40°C.

[0041] Subsequently, a mixed solution of a fluorine-containing alcohol solvent and an organic base is added, and the mixture is cooled to crystallize. The fluorine-containing alcohol solvent is preferably one or more selected from the group consisting of trifluoromethanol, trifluoroethanol, trifluoropropanol, and trifluorothanol. The volume ratio of the cyclic ether solvent to the fluorine-containing alcohol solvent is preferably 1:(1-10), more preferably 1:(1-8), even more preferably 1:(1-7), and most preferably 1:(1-5). In some embodiments of the present invention, the volume ratio of the cyclic ether solvent to the fluorine-containing alcohol solvent is specifically 1:5 or 1:1. The mass of the organic base is preferably 0.01-10% of the mass of reduced coenzyme Q10, more preferably 0.5-10%, even more preferably 1-10%, and most preferably 5-10%. In some embodiments of the present invention, the mass of the organic base is 5%, 7%, or 10% of the mass of reduced coenzyme Q10. The crystallization may be performed at room temperature or by cooling, preferably by cooling, or by combining cooling with another crystallization method. Specifically, the crystallization is preferably performed at a temperature of 0°C to 20°C. More specifically, in the present invention, the crystallization is preferably performed at a temperature of 0°C to 10°C or 10°C to 20°C, more preferably at a temperature of 0°C to 5°C or 10°C to 15°C. The crystallization is preferably performed for 6 hours or more, more preferably for 6 to 24 hours. Specifically, in the present invention, the crystallization is performed for 6 to 12 hours when performed at a temperature of 0°C to 10°C, and for 12 to 24 hours when performed at a temperature of 10°C to 20°C. The crystallization can be performed in a standing state or with stirring, but is not particularly limited, and stirring is preferred in the present invention. The rotation speed of the stirring is 200 r / min or more. In the present invention, the crystal species can also be added after cooling. The crystal species is a crystal of reduced coenzyme Q10. The crystal form of the reduced coenzyme Q10 crystal used as the crystalline species in this invention is not particularly limited; it may be the crystalline form according to the present invention, or it may be type I prepared in conventional literature, but is not particularly limited. Crystallization is induced by adding the crystalline species.The amount of the crystalline species added is not particularly limited, and the mass of the crystalline species in the present invention is preferably 0.1% or more of the mass of reduced coenzyme Q10, more preferably 0.15 to 5%, even more preferably 0.1% to 3%, even more preferably 0.5% to 3%, even more preferably 1% to 2%, and most preferably 1% to 1.5%.

[0042] Under the crystallization conditions described above, these solvents can be mixed in a preferred ratio according to the properties of each solvent in order to improve conditions that affect crystallization, such as the solubility, concentration, yield, slurry properties, or crystalline properties of reduced coenzyme Q10.

[0043] In one specific embodiment of the present invention, the crystallization concentration and the holding time after crystallization can be appropriately determined to obtain the desired reduced coenzyme Q10 crystals, taking into consideration the solubility of reduced coenzyme Q10 in the solvent. For example, when 2-methyltetrahydrofuran is used as the solvent, a 2-methyltetrahydrofuran solution of reduced coenzyme Q10 is prepared at a concentration of 50% at 40°C or below, a fluorine-containing alcohol solvent and an organic base are added, and then the solution is cooled and crystallized to 10°C to precipitate reduced coenzyme Q10 crystals. The precipitated reduced coenzyme Q10 crystals are then held in the solvent at that temperature for 6 hours or more, preferably 8 hours or more, and more preferably 12 hours or more to produce the crystals. In this holding step, the mixture of precipitated reduced coenzyme Q10 crystals and the solvent may be stirred or left standing, but stirring is preferred. The stirring speed should be 200 r / min or more.

[0044] After crystallization, the crystals are recovered by processes such as solid-liquid separation and drying, if necessary, using conventionally known methods such as those described in patent documents. For example, pressure filtration or centrifugal filtration can be used for solid-liquid separation, but pressure filtration with an inert gas is usually used. The drying temperature can be determined by the boiling point of the added solvent, and is generally kept below 45°C. The crystalline solid after drying can also be recovered by grinding or classifying (sieving) as necessary to obtain crystals of reduced coenzyme Q10.

[0045] Furthermore, the crystallization and post-treatment processes described above are preferably carried out under a deoxygenated atmosphere. A deoxygenated atmosphere can be achieved by substitution with an inert gas. Examples of inert gases include nitrogen gas, helium gas, argon gas, and carbon dioxide, but nitrogen gas or argon gas is preferred.

[0046] Furthermore, if crystals of reduced coenzyme Q10 can be manufactured or obtained once, the crystals of reduced coenzyme Q10 of the present invention can be manufactured under general conditions by adding the crystals of reduced coenzyme Q10 of the present invention as seed crystals when performing the crystallization operation. In this case, the crystallization can be carried out using room temperature crystallization or cold crystallization. Preferred crystallization methods are cold crystallization, or a method that combines cold crystallization with other crystallization methods.

[0047] The present invention also provides a crystalline solid of reduced coenzyme Q10, which includes the crystals of reduced coenzyme Q10 described above.

[0048] Specifically, the crystalline solid of the reduced coenzyme Q10 is obtained by adding reduced coenzyme Q10, with the crystalline form of the reduced coenzyme Q10 according to this application removed, as a crystalline species during the crystallization process.

[0049] More specifically, the reduced coenzyme Q10 crystals described above have a content of reduced coenzyme Q10 in the crystalline solid preferably of 0.1 wt% or more, more preferably 1 wt% or more, even more preferably 10 wt% or more, even more preferably 30 wt% or more, even more preferably 50 wt% or more, even more preferably 70 wt% or more, and most preferably 85 wt% or more. When the lower limit of the content of reduced coenzyme Q10 crystals according to the present invention is the above value, the upper limit corresponding to each lower limit is, needless to say, 100 wt%. Whether reduced coenzyme Q10 crystals and crystalline forms reported in conventional literature are in a mixed state and their ratio in the reduced coenzyme Q10 crystals and crystalline solid according to the present invention can be determined, for example, by measuring with a heating rate of 1 k / min using DSC. Under these conditions, the endothermic peaks indicating the melting of conventionally known reduced coenzyme Q10 crystals and the melting of reduced coenzyme Q10 crystals according to the present invention are clearly separated. Since the magnitude of these peaks correlates with the mixing ratio, even when the reduced coenzyme Q10 crystals or crystalline solids of the reduced coenzyme Q10 according to the present invention are mixed with reduced coenzyme Q10 crystals reported in conventional literature, the presence and content of novel reduced coenzyme Q10 crystals can be clearly measured.

[0050] The crystals of reduced coenzyme Q10 according to the present invention may form a crystalline solid in coexistence with crystals of reduced coenzyme Q10 reported in conventional literature, as long as they have the above-mentioned DSC endothermic peak, XRD diffraction pattern, and IR absorption pattern. Furthermore, any crystalline solid containing crystals of reduced coenzyme Q10 according to the present invention is included within the scope of the present invention, regardless of whether other solid forms of reduced coenzyme Q10 coexist or not. It should be noted that the crystals of reduced coenzyme Q10 contained in the crystals of reduced coenzyme Q10 according to the present invention are more stable than the crystalline forms reported in conventional literature. Therefore, even if only a small amount of crystals of reduced coenzyme Q10 are present in the crystalline solid of reduced coenzyme Q10 according to the present invention, over time, all of the crystalline forms can be transformed into crystals of reduced coenzyme Q10 according to the present invention.

[0051] The present invention also provides a reduced coenzyme Q10 composition comprising the above-described crystals of reduced coenzyme Q10 and / or the above-described crystalline solid of reduced coenzyme Q10.

[0052] The reduced coenzyme Q10 crystals, reduced coenzyme Q10 crystalline solids, and reduced coenzyme Q10 compositions according to the present invention can be used in applications such as food, nutritional functional foods, foods for specified health uses, nutritional supplements, nutritional supplements, animal drugs, beverages, feed, cosmetics, pharmaceuticals, therapeutic drugs, preventive drugs, or pet food. [Examples]

[0053] To further illustrate the present invention, the crystals of reduced coenzyme Q10 according to the present invention and the method for producing the same will be described in detail below with reference to examples.

[0054] The measurement conditions for powder X-ray diffraction (XRD), differential scanning calorimetry (DSC), and infrared spectroscopy (IR) analysis in the examples are as follows.

[0055] (XRD measurement conditions) Instrument model number: Powder X-ray diffractometer / Smart Lab SE; X-ray tube: Cu target; Speed: 10° / min; Scanning angle: 3°~60°; Step size: 0.02°; Slit width: 10mm; Output voltage: 40kV; Output current: 40mA. (DSC measurement conditions) Instrument model number: Differential scanning calorimeter / Netzsch DSC 214; Sample crucible: Concavus Al; Heating rate: 10K / min; Detection temperature range: 30°C to 300°C; Purge / protection gas: N2. (IR measurement conditions) Equipment model number: Shimadzu IRTracer-100 Fourier transform infrared spectrophotometer; Measurement method: KBr tablet method.

[0056] (Example 1) Under the protection of nitrogen gas, 100 g of commercially available reduced coenzyme Q10 (99.5% purity) and 200 mL of 2-methyltetrahydrofuran were placed in a 3 L three-necked flask and heated to 40°C with stirring until completely dissolved. This solution was cooled to 10°C, 1000 mL of trifluoroethanol and 5 g of triethylamine were slowly added dropwise, and after cooling to 2°C, stirring was continued for 12 hours. The solution was then filtered, washed with 20 mL of trifluoroethanol, and dried under reduced pressure at 40°C for 6-8 hours to obtain granular crystals (crystals of reduced coenzyme Q10).

[0057] As shown in Figure 3, DSC analysis revealed an endothermic peak indicating melting at 52.2°C when the temperature was increased at a rate of 10 kJ / min.

[0058] Analysis by powder X-ray diffraction revealed characteristic peaks at diffraction angles (2θ±0.2°) of 8.95°, 10.04°, 15.09°, 17.36°, 18.65°, 19.03°, 20.19°, 21.61°, and 23.01°, as shown in Figure 1.

[0059] Furthermore, as shown in Figure 2, the IR analysis revealed that, unlike the reduced coenzyme Q10 crystals reported in previous literature, the crystals were 794±1 cm². -1 , 877±1cm -1 , 962cm -1 and 1014cm -1 A characteristic absorption peak was observed in the vicinity.

[0060] From the above analysis results, it was confirmed that the crystal form of reduced coenzyme Q10 obtained in this example differs from that of reduced coenzyme Q10 reported in conventional literature. When the solubility of the obtained crystals in purified water was measured, it was found to be 0.5% by weight at a temperature of 25°C.

[0061] (Example 2) Under the protection of nitrogen gas, 100 g of commercially available reduced coenzyme Q10 (99.5% purity) and 1000 mL of 2,5-dimethyltetrahydrofuran were placed in a 3 L three-necked flask and heated to 40°C with stirring until completely dissolved. 1000 mL of trifluoropropanol and 7 g of triethylamine were slowly added dropwise, and after cooling to 10°C, 1 g of crystal species (obtained in Example 1) was added, and after stirring for 1 hour, it was cooled to 2°C, held for 12 hours with continued stirring, filtered, washed with 20 mL of trifluoropropanol, and dried under reduced pressure at 40°C for 6-8 hours to obtain crystals.

[0062] DSC analysis revealed an endothermic peak indicating melting at 50.2°C when the temperature was increased at a rate of 10 kJ / min.

[0063] Analysis and detection of the crystals obtained in Example 2 using powder X-ray diffraction and infrared spectroscopy revealed that the detection results were the same as in Example 1, with the error within the acceptable range, confirming that the crystals obtained in Example 2 were identical to those obtained in Example 1.

[0064] From the above analysis results, it was confirmed that the crystal form of reduced coenzyme Q10 obtained in this example differs from that of reduced coenzyme Q10 reported in conventional literature. When the solubility of the obtained crystals in purified water was measured, it was found to be 0.5% by weight at a temperature of 25°C.

[0065] (Implementation benefit 3) Under the protection of nitrogen gas, 100 g of commercially available or homemade reduced coenzyme Q10 and 1000 mL of tetrahydrofuran were placed inside a 3 L three-necked flask and heated to 40°C while stirring until completely dissolved. 1000 mL of trifluoroethanol and 10 g of triethylamine were added dropwise, and after cooling to 10°C, 1 g of crystal species (obtained in Example 1) was added, and after stirring for 1 hour, it was cooled to 2°C, held for 12 hours while continuing to stir, filtered, washed with 20 mL of trifluoroethanol, and dried under reduced pressure at 40°C for 6-8 hours to obtain crystals.

[0066] DSC analysis revealed an endothermic peak indicating melting at 52.2°C when the temperature was increased at a rate of 10 kJ / min. Furthermore, powder X-ray diffraction analysis confirmed that the reduced coenzyme Q10 crystals obtained in this example had the same crystal structure as the reduced coenzyme Q10 in Example 1.

[0067] (Comparative Example 1) (Example 1 of CN103635452A) After purging the inside of a 300 mL reaction flask (made of heat-resistant glass) with nitrogen, 40 g of commercially available reduced coenzyme Q10 (manufactured by Kaneka Corporation, a conventionally known crystal of reduced coenzyme Q10) and 60 g of n-hexane were added, and the solution was heated to 40°C while stirring until completely dissolved. This solution was cooled to 25°C at a cooling rate of 10°C / hour, and then maintained at 25°C for 96 hours while continuing to stir. Crystals were obtained by filtration and drying (vacuum drying, 20-40°C).

[0068] DSC analysis revealed an endothermic peak indicating melting at 50.2°C when the temperature was increased at a rate of 10 kJ / min.

[0069] Furthermore, analysis by powder X-ray diffraction revealed, as shown in Figure 4, that the reduced coenzyme Q10 crystals obtained in Comparative Example 1 were not the type II crystals reported in conventional literature, but rather the same crystal form as the reduced coenzyme Q10 type I crystals reported in conventional literature. Experiments also demonstrated that the crystal form obtained when using solvents reported in other patents, such as ethanol and heptane, was also type I as shown in Figure 4. Therefore, it was demonstrated that it should be difficult to improve the stability of reduced coenzyme Q10 by crystallization using conventional solvents.

[0070] (Example 4) The reduced coenzyme Q10 crystals obtained in Example 1 and Comparative Example 1 were each placed in vacuum bags and stored in the dark at 25°C. The weight ratio of reduced coenzyme Q10 to oxidized coenzyme Q10 was determined by the following HPLC analysis method, and the results are shown in Table 1 below. Figure 5 shows the HPLC chromatogram of the reduced coenzyme Q10 crystals obtained in Example 1 after being stored for 360 days. Figure 6 shows the HPLC chromatogram of the reduced coenzyme Q10 crystals obtained in Comparative Example 1 after being stored for 360 days.

[0071] (HPLC analysis conditions) Column: Agilent ZORBAX Extend C18 4.6×150mm, 5um; Mobile phases: Mobile phase A: Acetonitrile, Mobile phase B: Isopropanol, Mobile phase C: Methanol; Detection wavenumber: 290nm; Flow rate: 1.5ml / min; Column temperature: 35°C; Sample injection concentration: 1 mg / mL; Sample injection volume: 20 μL.

[0072] The elution program is shown in Table 2 below.

[0073] [Table 1]

[0074] [Table 2]

[0075] From these results, it was confirmed that the crystals of reduced coenzyme Q10 according to the present invention are more stable than the crystal forms described in conventional literature, and that higher purity can be obtained using this crystallization method.

[0076] (Comparative Example 3) The detection was performed using the liquid chromatography method described in Patent CN103635452, and the results are shown in Figures 7 and 8. Figure 7 is the HPLC chromatogram of the reduced coenzyme Q10 crystals obtained in Example 1, and Figure 8 is the HPLC chromatogram of the reduced coenzyme Q10 crystals obtained in Comparative Example 1. From this, it was found that the results obtained by the conventional method and the method described in the literature are similar.

[0077] (Example 5) Table 3 below shows the results of measuring solvent residue in the reduced coenzyme Q10 crystals obtained in Example 1 and Comparative Example 1.

[0078] (GC analysis conditions) Column: PEG-20M 30m x 0.53mm, 1.0μm or equivalent capillary column; Heating rate: The initial temperature was maintained at 35°C for 10 minutes, and then it was raised to 220°C at a rate of 20°C / min. Sample injection temperature: 200°C; Detector temperature: 250°C; Headspace time: 20 min; Headspace temperature: 70°C; Sample injection volume: 1 mL.

[0079] [Table 3]

[0080] The preferred embodiments of the present invention disclosed above are for illustrative purposes only and are not limiting to the present invention. Those skilled in the art will understand that modifications can be made to the technical methods of the present invention and that some technical features can be combined in other ways within the scope of the technical concept of the present invention. Such modifications or combinations do not deviate from the spirit and scope of the various embodiments of the present invention and should be considered as part of the disclosures of the present invention, and all such modifications or combinations are within the scope of protection of the present invention.

Claims

1. A crystal of reduced coenzyme Q10, characterized by having an endothermic peak at 52±2°C when measured by differential scanning calorimetry while increasing the temperature at a rate of 10 kJ / min.

2. The crystal of reduced coenzyme Q10 according to claim 1, characterized in that, in the powder X-ray diffraction pattern obtained by measurement using Cu-Kα rays, characteristic peaks are shown at diffraction angles (2θ±0.2°) of 8.95°, 10.04°, 15.09°, 18.65°, 19.03°, 21.61°, and 23.01°.

3. In the infrared absorption spectrum obtained by the KBr tablet method, the wavenumber was 794 ± 1 cm⁻¹. －１ , 877±1cm －１ 962cm －１ and 1014 cm －１ A crystal of reduced coenzyme Q10 according to claim 1, characterized by having a characteristic absorption peak.

4. The powder X-ray diffraction pattern obtained by the Cu-Kα method is shown in Figure 1. and / or, having an infrared absorption spectrum obtained by the KBr tablet method shown in Figure 2, The crystal of reduced coenzyme Q10 according to claim 1, characterized in that it has and / or the differential scanning calorimetry curve shown in Figure 3.

5. A method for producing crystals of reduced coenzyme Q10, characterized by comprising the step of crystallizing reduced coenzyme Q10 in the presence of a cyclic ether solvent, a fluorine-containing alcohol solvent, and an organic base to obtain crystals of reduced coenzyme Q10.

6. The manufacturing method according to claim 5, characterized in that the above step specifically involves mixing and dissolving reduced coenzyme Q10 and a cyclic ether solvent under heating conditions, adding a mixed solution of a fluorine-containing alcohol solvent and an organic base, and cooling to crystallize at a crystallization temperature of 0°C to 20°C to obtain crystals of reduced coenzyme Q10.

7. The cyclic ether solvent is one or more selected from the group consisting of 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, tetrahydrofuran, and 2,5-dimethyltetrahydrofuran. The aforementioned fluorine-containing alcohol solvent is one or more selected from the group consisting of trifluoromethanol, trifluoroethanol, trifluoropropanol, and trifluorobutanol. The method for producing the product according to claim 5, characterized in that the organic base is one or more selected from the group consisting of triethylamine, pyridine, and piperidine.

8. The ratio of the reduced coenzyme Q10 to the cyclic ether solvent is 1 g: (1 to 10) mL. The volume ratio of the cyclic ether solvent to the fluorine-containing alcohol solvent is 1:(1 to 10), The manufacturing method according to claim 5, characterized in that the mass of the organic base is 0.1% to 10% relative to the mass of reduced coenzyme Q10.

9. Crystals of reduced coenzyme Q10 according to any one of claims 1 to 4, and / or crystals of reduced coenzyme Q10 produced by the manufacturing method described in any one of claims 5 to 8. A crystalline solid of reduced coenzyme Q10, characterized by containing [the specified substance].

10. Crystals of reduced coenzyme Q10 according to any one of claims 1 to 4, and / or crystals of reduced coenzyme Q10 produced by the manufacturing method described in any one of claims 5 to 8, and / or a crystalline solid of the reduced coenzyme Q10 according to any one of claims 9. A reduced coenzyme Q10 composition characterized by containing the following:

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