阅读说明：本技术 丁香酸/碘海醇共晶体的制备方法及其应用 (Preparation method and application of syringic acid/iohexol eutectic ) 是由 孔宝睿 徐莹莹 刘宇 于 2021-09-26 设计创作，主要内容包括：本发明公开了丁香酸/碘海醇共晶体的制备方法及其应用。将丁香酸与碘海醇以2:1的摩尔比混合溶解在一定量有机溶剂中,在30℃～60℃恒温水浴加热至全溶,而后置于真空干燥箱中50℃～60℃干燥18h～20h,得丁香酸/碘海醇共晶体。本发明通过溶剂蒸发法制备药物共晶,制备方法简便高效,条件温和。丁香酸是脂溶性的,选用的造影剂碘海醇是水溶性的,共晶可以显著改善丁香酸的溶解度,使两种药物联合应用,相互补充。本发明切实解决相关群体痛点,主要针对儿童和需要经常做CT的病人,利用丁香酸/碘海醇共晶体抗氧化损伤辐射防护作用与造影作用,减少病情进一步恶化的风险。(The invention discloses a preparation method and application of syringic acid/iohexol eutectic. Mixing and dissolving the syringic acid and the iohexol in a certain amount of organic solvent according to the molar ratio of 2:1, heating the mixture in a constant-temperature water bath at the temperature of between 30 and 60 ℃ until the mixture is completely dissolved, and then placing the mixture in a vacuum drying oven for drying at the temperature of between 50 and 60 ℃ for 18 to 20 hours to obtain the syringic acid/iohexol eutectic. The invention prepares the pharmaceutical co-crystal by a solvent evaporation method, and the preparation method is simple, convenient and efficient and has mild conditions. Syringic acid is fat-soluble, the selected contrast agent iohexol is water-soluble, and the eutectic can obviously improve the solubility of syringic acid, so that the two medicaments are combined for application and supplement each other. The invention practically solves the pain points of related groups, mainly aims at children and patients needing to be frequently CT, and reduces the risk of further worsening of the state of an illness by utilizing the anti-oxidative damage radiation protection effect and the contrast effect of the syringic acid/iohexol eutectic.)

1. The preparation method of the syringic acid/iohexol eutectic is characterized by comprising the following steps: mixing appropriate amount of syringic acid and iohexol, adding appropriate amount of organic solvent, heating in water bath until syringic acid and iohexol are completely dissolved, and oven drying the obtained mixed solution to obtain syringic acid/iohexol eutectic.

2. The method according to claim 1, wherein the ratio of syringic acid to iohexol is 2: 1.

3. The method according to claim 1, wherein the organic solvent is selected from the group consisting of methanol, ethyl acetate, absolute ethanol, isopropanol, and dichloromethane.

4. The method according to claim 3, wherein the organic solvent is methanol.

5. The method according to claim 1, wherein the amount of the organic solvent is the minimum amount at which the appropriate amount of syringic acid and iohexol are completely dissolved.

6. The method of claim 1, wherein the temperature of the water bath heating is 30 ℃ to 60 ℃.

7. The preparation method according to claim 1, wherein the drying temperature is 50-60 ℃ and the drying time is 18-20 h.

8. Use of the syringic acid/iohexol cocrystal according to any one of claims 1 to 7 in the preparation of a synergistic radioprotective and contrast agent.

Technical Field

The invention belongs to the technical field of pharmaceutical co-crystals, and particularly relates to a preparation method and application of a syringic acid and iohexol co-crystal.

Background

Syringaldehyde has wide application prospect as a radiation-proof medicament. The radioprotectant taking syringaldehyde as an active ingredient has low toxicity, no adverse obvious reaction and obvious curative effect. The performances show the unique part of syringaldehyde in reducing cancer occurrence by radiation, and the syringaldehyde has wide application prospect in the field of national defense medicine.

Research shows that the radiation protection effect of syringaldehyde mainly comes from a metabolite syringic acid after the syringaldehyde is orally taken, and the syringic acid is white or white-like crystalline powder, is slightly soluble in water and needs to be stored away from light. Has antibacterial, tranquilizing and local anesthetic effects. The research on the radiation protection effect of the syringic acid through animal experiments shows that the syringic acid has the radiation protection effect on oxidation damage resistance.

Iohexol is a white or off-white powder or crystalline powder, odorless and hygroscopic. It is very soluble in water or methanol, and hardly soluble in chloroform or diethyl ether. Iohexol, as a non-ionic water-soluble contrast agent, has the advantages of low contrast density, low toxicity, good tolerance and the like, and is one of the best contrast agents at present.

Pharmaceutical co-crystals are crystals in which an Active Pharmaceutical Ingredient (API) and a co-crystal former (CCF) are bonded at a fixed stoichiometric ratio by the action of non-covalent bonds such as hydrogen bonds. Wherein the API and CCF are both solid at room temperature. The maximum application value of the pharmaceutical co-crystal is that the physicochemical properties of the pharmaceutical co-crystal can be improved without changing the molecular structure of the drug. Can improve the solubility of API, increase the stability, bioavailability, dissolution rate and the like, has good eutectic stability, and saves time and money in the preparation process of the eutectic, so that the eutectic and the preparation method thereof have attracted wide attention of the pharmaceutical research community in recent years as a new pharmaceutical preparation mode.

No relevant literature publication of the syringic acid and iohexol eutectic exists at present.

Disclosure of Invention

In order to solve the technical problems, the invention provides a preparation method of a syringic acid and iohexol eutectic. The pharmaceutical co-crystal is prepared by adopting a solvent evaporation method, the preparation method is simple, convenient and efficient, the conditions are mild, and the solubility of the syringic acid is obviously improved.

In order to achieve the purpose, the invention adopts the technical scheme that: the preparation method of the syringic acid/iohexol eutectic comprises the following steps: mixing appropriate amount of syringic acid and iohexol, adding appropriate amount of organic solvent, heating in water bath until syringic acid and iohexol are completely dissolved, and oven drying the obtained mixed solution to obtain syringic acid/iohexol eutectic.

Further, the above preparation method comprises that the ratio of syringic acid and iohexol is 2:1 by mol.

Further, in the above preparation method, the organic solvent is one or a combination of two or more selected from methanol, ethyl acetate, absolute ethyl alcohol, isopropyl alcohol and dichloromethane.

Further, in the above preparation method, the organic solvent is methanol.

Furthermore, in the preparation method, the dosage of the organic solvent is the minimum dosage for completely dissolving a proper amount of syringic acid and iohexol.

Further, in the preparation method, the temperature of water bath heating is 30-60 ℃.

Further, according to the preparation method, the drying temperature is 50-60 ℃, and the drying time is 18-20 hours.

The syringic acid/iohexol eutectic provided by the invention is applied to the preparation of the cooperative radiation-proof and contrast-improving medicines.

Compared with the prior art, the invention has the beneficial effects that:

1. the syringic acid/iohexol eutectic provided by the invention has better chemical stability and higher solubility.

2. The syringic acid/iohexol eutectic prepared by the invention jointly applies the antioxidant damage radiation protection effect of the syringic acid and the contrast effect of iohexol, and opens up a new idea for clinically exploring the radiation protection problem in CT examination of children.

3. The preparation method of the syringic acid/iohexol eutectic provided by the invention is simple and easy to implement, mild in condition, easy to control, good in reproducibility, easy to realize large-scale industrial production, low in production cost and great in commercial application value.

Drawings

FIG. 1 is a DSC chart of syringic acid/iohexol obtained by dry milling for 10min at a molar ratio of 2:1 in example 1.

FIG. 2 is a DSC chart of syringic acid/iohexol obtained in example 2 at a molar ratio of 2:1 and by adding a drop of absolute ethanol for auxiliary milling.

FIG. 3 is a DSC chart of syringic acid/iohexol obtained in example 2 at a molar ratio of 2:1 and with the addition of one drop of isopropanol assisted trituration.

FIG. 4 is an infrared spectrum (IR) chart of syringic acid crude drug (a) and iohexol pure product (b).

FIG. 5 is a chart of the infrared spectrum (IR) of the syringic acid/iohexol cocrystal prepared in example 3 at a molar ratio of 2:1 and dissolved by addition of 2ml of ethyl acetate and 1ml of methanol.

FIG. 6 is a chart of the infrared spectrum (IR) of syringic acid/iohexol cocrystals prepared in example 3 at a molar ratio of 2:1 and dissolved by addition of 3ml of absolute ethanol and 2ml of dichloromethane.

FIG. 7 is a DSC chart of the syringic acid/iohexol (molar ratio 2:1) co-crystal prepared under the best conditions of example 6.

FIG. 8 is a graph of the infrared spectrum (IR) of the syringic acid/iohexol (molar ratio 2:1) cocrystal prepared under the optimal conditions for example 6.

Detailed Description

The invention is further illustrated by the following detailed description in conjunction with the accompanying drawings. The examples are given solely for the purpose of illustration and are not to be construed as limitations of the present invention, as variations and modifications thereof which would be obvious to those skilled in the art are intended to be included within the scope of the present invention.

Example 1

Effect of different molar ratios on syringic acid/iohexol cocrystals

The method comprises the following steps: adding the syringic acid and the iohexol into an agate mortar according to the mol ratio of 1:1 to 2:1 to 3:1, and fully grinding for 10min by a dry grinding method, wherein the results are shown in table 1 and fig. 1.

TABLE 1

Molar ratio of	Results
		Syringic acid iohexol 1:1	Only the raw materials are mixed, and no new substances are generated
Syringic acid iohexol 2:1	Production of novel substances
		Syringic acid iohexol 3:1	Only the raw materials are mixed, and no new substances are generated

As can be seen from Table 1, the sample prepared by mixing and dry-grinding the syringic acid and the iohexol in the molar ratio of 2:1 for 10min generates new substances and eutectic formation, and the samples are only mixed by two raw material medicines in other molar ratios without generating new substances. Therefore, the invention adopts the mol ratio of the syringic acid to the iohexol of 2: 1.

FIG. 1 is a DSC chart of syringic acid/iohexol obtained by dry grinding at a molar ratio of 2:1 for 10 min. As can be seen from fig. 1, the melting point of the prepared eutectic sample is higher than that of the bulk drug, and is not the superposition of the respective melting points of syringic acid and iohexol. Therefore, the syringic acid and the iohexol generate a new phase and form a eutectic crystal.

Example 2

Influence of different organic solvents and addition amounts on syringic acid/iohexol cocrystals

(one) Effect of addition of one drop of organic solvent on syringic acid/iohexol cocrystals

The method comprises the following steps: adding 0.2mmol syringic acid and 0.1mmol iohexol into agate mortar, respectively adding one drop (about 50 μ L) of organic solvent selected from methanol, ethyl acetate, absolute ethanol, isopropanol, dichloromethane, acetonitrile and acetone dropwise for auxiliary grinding for 5min by liquid-assisted grinding method. And transferring the sample to a small beaker after grinding, sealing, standing at normal temperature, obtaining white solid powder after all the organic solvent is volatilized, and carrying out DSC detection to judge whether eutectic is formed.

The result shows that the result of the auxiliary grinding by adding one drop of organic reagent is not ideal, and eutectic crystal is not formed. FIG. 2 is a DSC chart of syringic acid/iohexol obtained by adding a drop of anhydrous ethanol for auxiliary grinding in a molar ratio of 2: 1. As can be seen from FIG. 2, the melting point of the prepared sample is not obviously changed compared with the two bulk drugs, and eutectic crystal is not formed. FIG. 3 is a DSC chart of syringic acid/iohexol obtained with a molar ratio of 2:1 and addition of a drop of isopropanol for additional milling. As can be seen from FIG. 3, the melting point of the prepared sample is not obviously changed compared with the two bulk drugs, and eutectic crystal is not formed.

(II) Effect of the amount of organic solvent used to dissolve syringic acid and iohexol to saturation on syringic acid/iohexol cocrystals

The method comprises the following steps: adding 0.2mmol syringic acid and 0.1mmol iohexol into 25ml beaker, adding organic solvent selected from methanol, ethyl acetate, anhydrous ethanol, isopropanol, dichloromethane, acetonitrile, acetone to dissolve to saturation state. After sealing, standing at normal temperature until all the organic solvent is volatilized to obtain white solid powder, and the results are shown in Table 2.

TABLE 2

Organic solvent	Amount of addition	Results
			Methanol	2.5ml	Completely dissolving and precipitating crystals
Ethyl acetate	3ml	Partially dissolved and crystallized
			Anhydrous ethanol	3ml	Partially dissolved and crystallized
Isopropanol (I-propanol)	2.5ml	Partially dissolved and crystallized
			Methylene dichloride	3ml	Partially dissolved and crystallized
Acetonitrile	4ml	Does not dissolve and does not precipitate crystals
			Acetone (II)	3ml	Does not dissolve and does not precipitate crystals

As can be seen from Table 2, the samples prepared by adding a sufficient amount of organic solvent to dissolve by the solvent evaporation method all precipitated crystals except acetonitrile and acetone, and eutectic crystals were generated. Preferred organic solvents for the present invention are methanol, ethyl acetate, absolute ethanol, isopropanol and dichloromethane.

Example 3

Screening for optimal organic solvents

The method comprises the following steps: adding 0.2mmol of syringic acid and 0.1mmol of iohexol into a 25ml beaker, adding an organic solvent, wherein the dosage of the organic solvent is the lowest dosage for completely dissolving the syringic acid and the iohexol, the organic solvent is selected from one or two of methanol, absolute ethyl alcohol, dichloromethane and isopropanol, heating in a constant temperature water bath at 40 ℃ until the sample is completely dissolved, and then drying in a vacuum drying oven at 60 ℃ for 20 hours to obtain a white solid, namely the syringic acid/iohexol eutectic, and the results are shown in Table 3, and figures 5 and 6.

TABLE 3

FIG. 4 is an infrared spectrum (IR) chart of syringic acid crude drug (a) and iohexol pure product (b).

FIG. 5 is a graph of the infrared spectrum (IR) of a syringic acid/iohexol cocrystal prepared in a 2:1 molar ratio and dissolved by the addition of 2ml ethyl acetate and 1ml methanol. As can be seen from the comparison of FIG. 5 and FIG. 4, the characteristic peak of the sample prepared by adding 2ml of ethyl acetate and 1ml of methanol to dissolve the sample and the characteristic peak of the syringic acid bulk drug are not greatly changed, and the phenomenon that the characteristic peak is obviously moved due to hydrogen bonds is avoided, so that the preparation of the eutectic sample is not the most preferable.

FIG. 6 is a graph of the infrared spectrum (IR) of a syringic acid/iohexol cocrystal prepared in a molar ratio of 2:1 and dissolved by adding 3ml of absolute ethanol and 2ml of dichloromethane. As can be seen from the comparison of the figure 6 and the figure 4, the infrared spectrum characteristic peak of the sample prepared by adding 3ml of absolute ethyl alcohol and 2ml of dichloromethane in the molar ratio of 2:1 and dissolving is basically consistent with the characteristic peak of the bulk drug of iohexol, which indicates that the sample prepared by the method is precipitated and crystallized into iohexol without generating new substances.

The final conclusion from this example is that the solvent evaporation method is ideal for sample preparation, with methanol being the most preferred organic solvent and 2ml being the most preferred amount to be added.

Example 4

Effect of Water bath temperature on syringic acid/iohexol cocrystals

The method comprises the following steps: adding 0.2mmol syringic acid and 0.1mmol iohexol into a 25mL beaker, adding 2mL methanol, heating in a constant temperature water bath at 10 ℃, 20 ℃, 30 ℃, 40 ℃, 50 ℃, 60 ℃ and 70 ℃ respectively until the sample is completely dissolved, and then drying in a vacuum drying oven at 60 ℃ for 20h to obtain white solid, namely the syringic acid/iohexol eutectic, wherein the results are shown in Table 4.

TABLE 4

Temperature of water bath	Results
		10℃	Partial dissolution and unsatisfactory crystallization rate
20℃	Partial dissolution and unsatisfactory crystallization rate
		30℃	Complete dissolution and high crystallization rate
40℃	Complete dissolution and high crystallization rate
		50℃	Complete dissolution and high crystallization rate
60℃	Complete dissolution and high crystallization rate
		70℃	Complete dissolution, over-high temperature and crystal form damage

As shown in Table 4, syringic acid and iohexol are completely dissolved in a methanol solution under the heating of a water bath at 30-60 ℃, the crystallization rate is high, and the crystal form is good. The two raw materials cannot be completely dissolved at too low water bath temperature, and the crystal form is damaged at too high water bath temperature. Therefore, according to the invention, the bath temperature is preferably between 30 and 60 ℃.

Example 5

Effect of drying temperature on syringic acid/iohexol cocrystals

The method comprises the following steps: adding 0.2mmol of syringic acid and 0.1mmol of iohexol into a 25mL beaker, adding 2mL of methanol, heating in a constant temperature water bath at 40 ℃ respectively until the samples are completely dissolved, and drying in a vacuum drying oven at 40 ℃, 50 ℃, 60 ℃ and 70 ℃ respectively for 20h to obtain white solids, namely syringic acid/iohexol eutectic, wherein the results are shown in Table 5.

TABLE 5

Drying temperature	Results
		40℃	Sticky and not completely dry
50℃	Complete drying, good eutectic crystal form and stable property
		60℃	Complete drying, good eutectic crystal form and stable property
70℃	Drying completely, solidifying white solid, and destroying crystal form

As can be seen from Table 5, the eutectic crystal is completely dried at the drying temperature of 50-60 ℃, the form is good, the property is stable, and the drying time is reasonable. The drying temperature is too low, so that the drying is incomplete, the sample is still sticky, and the time required for drying is too long; too high drying temperature leads to excessive drying of the sample, crystal form damage and loss of activity. Therefore, the drying temperature is preferably 50-60 ℃.

Example 6 syringic acid/iohexol cocrystals

The preparation method comprises the following steps:

adding 0.2mmol of syringic acid and 0.1mmol of iohexol into a 25mL beaker, dropwise adding 2mL of methanol solution into the beaker, heating the beaker in a constant-temperature water bath at 40 ℃ until the sample is completely dissolved, and drying the sample in a vacuum drying oven at 60 ℃ for 20 hours to obtain a white solid, namely the syringic acid/iohexol eutectic.

(II) detection

1. The syringic acid bulk drug, the iohexol pure product and the syringic acid/iohexol eutectic prepared in this example were dried sufficiently before measurement, and then 5mg of each was subjected to thermal analysis in a DSC822e differential scanning calorimeter. Firstly, calibrating an instrument, and measuring all samples by using an aluminum crucible; an empty pan was sealed and used as a sample in the same manner. The test sample was heated at a rate of 10 ℃/min from 25 ℃ to 400 ℃ at room temperature, the results are shown in fig. 7.

As can be seen from FIG. 7, the syringic acid/iohexol cocrystal prepared in this example had an endothermic peak corresponding to a temperature of 305.818 ℃ and a peak of 29.288. Compared with the melting points of the raw syringic acid drug and the iohexol pure product, the syringic acid/iohexol eutectic prepared by the invention has higher melting point, and is not the superposition of the respective melting points of the syringic acid and the iohexol, which indicates that the syringic acid and the iohexol generate a new phase and form eutectic.

2. Weighing about 1mg of syringic acid raw material drug, iohexol pure product and the syringic acid/iohexol eutectic prepared in the example, which are dried to a constant weight, respectively, into an agate mortar, fully grinding, adding about 100mg of potassium bromide powder, uniformly grinding until the particle size is less than 2 μm, placing into a mold, pressing into transparent sheets on an oil press with a pressure of 60Pa, respectively performing infrared scanning, wherein the scanning wavelength is 400cm-4000cm, and respectively recording an FT-IR chart, and the result is shown in FIG. 8.

FTIR Fourier transform infrared is generally used for determining functional groups of organic matters, the functional groups of most organic matters absorb infrared light to different degrees, so that infrared spectrograms generate absorption peaks with different intensities under different wavelengths, and the composition of the organic matters can be judged according to the absorption characteristic peaks. If the two components react to form hydrogen bonds or other chemical interactions, the characteristic peaks in the corresponding infrared spectra are changed. As can be seen from fig. 8, the syringic acid/iohexol eutectic prepared in this example is significantly different from the infrared spectra of the syringic acid bulk drug and the iohexol pure product in fig. 4, and hydrogen bonds are formed, which proves the formation of the eutectic.