CN114486471A

CN114486471A - Standard storage solution of water-wheat winteric acid and preparation method thereof

Info

Publication number: CN114486471A
Application number: CN202210086378.2A
Authority: CN
Inventors: 王枫琦; 张田勇; 杨士杰; 丁慧; 许纪锋; 孙莉
Original assignee: Shanghai Standard Technology Co ltd
Current assignee: Shanghai Standard Technology Co ltd
Priority date: 2022-01-25
Filing date: 2022-01-25
Publication date: 2022-05-13

Abstract

The technical scheme of the invention is that the standard storage solution of the water-wheat winter acid has the water-wheat winter acid content of 0.01-10 mg/ml, and contains an alkalizer, so that the whole solution is alkaline. The standard storage solution of the water-wheat winter acid has high stability, and can be stably stored for a long time compared with a water-wheat winter acid reference solution obtained by the existing method. The preparation method of the water wheat winteric acid solution is simple and easy to use, does not need special steps to maintain the stability of the water wheat winteric acid, and has wide industrial application prospect.

Description

Standard storage solution of water-wheat winteric acid and preparation method thereof

Technical Field

The invention relates to a standard storage solution of water-wheat winter acid and a preparation method thereof, in particular to a preparation method of a water-wheat winter acid standard storage solution of high-concentration water-wheat winter acid which can be stored for a long time.

Background

The rhizoma Pinelliae is dried tuber of rhizoma Pinelliae (Pinellia ternata (Thunb.) Breit.) of Araceae. Collected in summer and autumn, washed, peeled and dried in the sun. The northeast, the north China and the Yangtze river basin are distributed. Has effects of eliminating dampness and phlegm, lowering adverse qi and relieving vomit, and relieving oppression and resolving hard mass. Can be used for treating damp phlegm, cold phlegm, cough, asthma, excessive phlegm, phlegm retention, dizziness, palpitation, dizziness, phlegm syncope, headache, emesis, nausea, feeling of fullness in chest and epigastrium, and globus hystericus; it is indicated for abscess with phlegm nodule. The counterfeit products of pinellia ternata on the market are more, wherein the tuber of tiger palm (Pinelliae Pedatisecta Schott) is a common adulterated product in the pinellia ternata, and the identification method of the pinellia ternata and the tuber of tiger palm is mainly character identification, but has great identification difficulty.

Pinellia tuber, rhizoma Pinelliae and Damnacanthus plant belonging to the same family as Damnacanthus genus are named because there are many small tubers, which are similar to "Damnacanthus tuber". Pinellia ternata is generally sown in 2-3 months and harvested in 8-9 months, the growing period is about 5 months, and the acre yield is 200-350 kg. The main production area is mainly concentrated in Gansu, Sichuan and Guizhou areas, the annual output is 4000-5000 tons, the annual demand is 8000-10000 tons, and the current market price is 85-120 yuan/kg and can reach 160 yuan/kg at most. The rhizoma arisaematis cum-tiger is generally sown in 6 months and harvested in 10 months, the growth period is 3-4 months, and the yield per mu is 300-400 kg. The main producing areas are mainly concentrated in the places of Hebei, Anhui, Heilongjiang and the like, the annual output is about 1 ten thousand tons, the main stream of the rhizoma arisaematis gradually becomes the commodity main stream, and the rhizoma pinelliae pseudo-filling area is used for filling about 3000 tons. The market price is 40-50 yuan/kg. In order to obtain benefits, the tiger palm is processed and then screened and polished, so that the original tuber characteristics are not obvious, are very similar to those of pinellia ternata and are difficult to identify; if the raw materials are processed into decoction pieces, the shape and the properties of the powder can hardly be identified.

The only reliable two-way identification method at present is chemical identification. Research indicates that the hordenic acid is a characteristic component for identifying pinellia ternate and tiger paw, and the pinellia ternate does not contain the hordenic acid, but the tiger paw contains a large amount of the hordenic acid. Therefore, whether the pinellia ternate is a counterfeit product or not or whether the tiger palm is adulterated or not can be judged by identifying whether the content of the water-wheat-winter-acid in the medicinal materials is present or not.

The molecular structural formula of the water-wheat winteric acid is shown in the specification, namely triglochic acid in English, and the water-wheat winteric acid is mainly derived from tiger palm.

Patent CN112500284A mentions that the water wheat winteric acid is unstable in various solvents, and the water wheat winteric acid is difficult to be purified by chromatography. In 2019, the national drug administration issued a supplement inspection method (hereinafter sometimes referred to as "national drug administration supplement inspection method") for the inspection item of the water-wheat-winteric acid in the pinellia ternata medicinal materials and decoction pieces, wherein the water-wheat-winteric acid is used as a reference substance and is dissolved in acetonitrile-0.1% phosphoric acid solution (1:99) to prepare a reference substance solution. Also because of the instability of the water-maltogenic acid in solution, the method is particularly emphasized and requires fresh preparation. This suggests that the problem of the instability of the hordenic acid may also exist in the state of the reference solution provided in the method for supplementing and inspecting the hordenic acid inspection item in the pinellia tuber medicinal material and decoction pieces issued by the State drug administration.

It is known that, because the components identified by the characteristic components in the traditional Chinese medicine identification are all trace, the solubility of the reference solution is relatively low, and in order to prepare the reference solution with accurate concentration, a reasonable method is to prepare a standard stock solution (generally, the solution is 2 to 3 orders of magnitude higher than the target solution) and then gradually dilute the standard stock solution to the required concentration so as to ensure the accuracy. However, the inventor finds that when a high-concentration stock solution is prepared by using a corresponding method in the 'national drug administration supplementary inspection method', the problem of serious decomposition also exists, which causes that a standard stock solution needs to be prepared again each time a new control solution is used, and simultaneously, the price of the water-wheat winteric acid is very expensive, and the price per gram is 6-10 ten thousand yuan, so that the step of obtaining the control solution in the current national drug administration supplementary inspection method is complicated, expensive and difficult to implement.

In addition, due to the stability of the existing water wheat winter acid in the water wheat winter acid reference solution, it is difficult to develop the transverse comparison of specificity, linear range, precision, accuracy, quantitative limit, durability and the like of various detection methods based on the same standard stock solution, and the research and development of the analysis and detection method of the water wheat winter acid are also very delayed because the variation of the standard stock solution directly causes the incredibility of the comparison result.

The instability in the solution limits the research progress of the water wheat winteric acid analysis test method, increases the cost of the existing analysis test method, and greatly limits the application range of the water wheat winteric acid standard substance in the identification of the traditional Chinese medicinal materials.

In summary, there is an urgent need to provide a standard stock solution of water-wheat winteric acid, which meets the requirement of storage stability, and the development of a preparation method for preparing a stable standard stock solution of water-wheat winteric acid is urgent.

Disclosure of Invention

In order to solve the problems of high cost, complex operation and non-ideal accuracy caused by the instability of the water-wheat winteric acid in the solution state in the existing supplement inspection method of the national drug administration, the inventor develops a novel water-wheat winteric acid standard stock solution and a preparation method thereof through deep research, and solves the problem of the instability of the water-wheat winteric acid solution state. Specifically, the method comprises the following steps:

the invention provides a standard stock solution of water-wheat winter acid, wherein the content of the water-wheat winter acid is 0.01-10 mg/ml, and the standard stock solution of the water-wheat winter acid contains an alkalizer, so that the whole solution is alkaline.

In a preferred embodiment of the invention, the concentration of the prepared water wheat winteric acid solution is 0.2 mg/mL-0.8 mg/mL, preferably, the concentration is 0.3 mg/mL-0.6 mg/mL.

In a preferred embodiment of the present invention, the alkalizing agent is at least one selected from the group consisting of triethylamine, sodium hydroxide, sodium carbonate, and sodium bicarbonate.

In a preferred embodiment of the invention, the standard stock solution of hordenic acid has a pH of 8 to 12, preferably a pH of 9 to 11.

In another embodiment of the present invention, a method for improving the stability of a solution of a compound of formula (I) is provided.

In a preferred embodiment of the present invention, the alkalizer is at least one selected from the group consisting of triethylamine, sodium hydroxide, sodium carbonate, and sodium bicarbonate.

In a preferred embodiment of the invention, the solution of the hordenic acid is adjusted to a pH of 8 to 12, preferably to a pH of 9 to 11.

In another embodiment of the present invention, there is also provided a method for preparing a solution of water-wheat winteric acid, comprising the following steps:

step S1: taking alkaline aqueous solution containing alkalizer and having pH value of 8-12,

step S2: weighing water wheat winteric acid with target content, dissolving in the alkaline aqueous solution,

step S3: in the solution obtained in step S2, an alkalizer is supplemented so that the pH of the entire solution is maintained at 8 to 12, and water is added to a target volume.

In a preferred embodiment of the present invention, the concentration of the water content of the ophiopogon acid is controlled to be 0.2 mg/mL-0.8 mg/mL, preferably 0.3 mg/mL-0.6 mg/mL, and the pH value of the solution to be metered in the step S3 is controlled to be 9-11 by using the alkalizer.

The invention has the following characteristics:

the standard storage solution of the water-wheat winter acid has high stability, and can be stably stored for a long time compared with a water-wheat winter acid reference solution obtained by the existing method. The preparation method of the water wheat winteric acid solution is simple and easy to use, does not need special steps to maintain the stability of the water wheat winteric acid, and has wide industrial application prospect.

Drawings

FIG. 1 is an HPLC detection profile at hour 0 in example 1;

FIG. 2 is a HPLC detection profile at 22 hours in example 1;

FIG. 3 is a HPLC check chart at hour 0 in example 2;

FIG. 4 is an HPLC detection profile at 8 hours in example 2;

FIG. 5 is a HPLC check chart at hour 0 in example 3;

FIG. 6 is a HPLC detection profile at hour 22 in example 3;

FIG. 7 is a HPLC check chart at hour 0 in example 4;

FIG. 8 is a HPLC check pattern at 21 hour in example 4;

FIG. 9 is a HPLC check chart at hour 0 in example 5;

FIG. 10 is a HPLC check map at hour 9 in example 5;

FIG. 11 is a HPLC check chart at hour 0 in example 6;

FIG. 12 is a HPLC check chart at 9 hours in example 6;

FIG. 13 is a HPLC check chart at hour 0 in example 7;

FIG. 14 is an HPLC check chart at 8 hours in example 7;

FIG. 15 is a HPLC check map at hour 0 in example 8;

FIG. 16 is a HPLC detection profile at hour 22 in example 8;

FIG. 17 is a HPLC check map at hour 0 in example 9;

FIG. 18 is a HPLC check map at 22 hours in example 9;

FIG. 19 is a combined HPLC check pattern at each time point in example 10;

FIG. 20 is a combined HPLC chromatogram at each time point in example 11.

Detailed Description

The following describes specific embodiments of the present invention.

As mentioned above, the supplementary test method for testing the content of the compound.

It is known that when preparing a standard solution, the original concentrated solution, which can be preserved for a long time, is called a standard stock solution; when diluted from an original concentrated solution to a diluted solution, it is often called a standard stock solution to prepare a standard working solution. The gradient dilution operation from thick to thin is very important for ensuring the content accuracy of the standard solution (the reference solution with specific concentration). Fresh standard solutions, meaning that the preparation is also started from stock solutions. The inventor finds that the stability of the water-wheat winteric acid in acetonitrile-0.1% phosphoric acid solution (1:99) (the solution condition of the supplement inspection method of the water-wheat winteric acid examination item in pinellia ternata medicinal materials and decoction pieces issued by the national drug administration) is not good even in the state of concentrated solution. Therefore, various attempts have been made to improve the stability of the solution, and the preparation of stock solutions in different acid solutions has been attempted in accordance with the idea of supplementing the test method with the test term of the water-wheat-winter-acid, but the results are not satisfactory (see examples described later).

Occasionally, the inventors found that the stability of the hordenic acid is better in an alkaline environment. Although the water-wheat winteric acid should be kept acidic in the eluent due to the carboxyl group contained therein according to the principle of HPLC detection, this is not a limitation that the standard solution must be an acidic solution. The accuracy and precision of the method cannot be influenced when a trace amount of alkaline solvent enters an HPLC analysis system. The inventors therefore tried to develop a method for maintaining the stability of the aqueous ophiopogon acid solution using an alkaline environment and to develop a corresponding stock solution of higher concentration of aqueous ophiopogon acid.

The stock solution in the present invention is not limited to an aqueous solution, and may be a solution prepared from another solvent, for example, a methanol solution or an acetonitrile solution.

Specifically, the technical scheme of the invention is that the standard storage solution of the water-wheat winter acid has the water-wheat winter acid content of 0.01-10 mg/ml, and the standard storage solution of the water-wheat winter acid contains an alkalizer, so that the whole solution is alkaline.

The term "alkaline" generally means a solution having a pH of >7 or a hydroxide ion concentration of > hydrogen ions at ordinary temperature, and a pH can be determined in a relatively simple manner by using a pH test paper or a pH reagent. In the present invention, it is preferable to maintain the stability of the water wheat winteric acid in a weak base environment. The reason why the stability of the compound in the alkaline environment is more excellent is not clear, and the fact that the acidic compound is more stable in the alkaline environment is not common knowledge, but is a special property of the compound itself, and the property is not common knowledge. So far, no research report about the stability of the water wheat winteric acid under different environments exists.

In a further preferred embodiment, the inventor of the present invention finds that the decomposition speed of the water-wheat winteric acid standard stock solution in the solution state is lower in the environment of pH8-12, and more preferably, in the alkaline solution environment of pH 9-11, the decomposition speed of the solution state is very low, so that the requirement of preparing the stock solution for long-term storage is met.

The solvent of each solution of the present invention is mainly water but is not limited thereto, and may be other solvents, and particularly, water, methanol, acetonitrile, a mixed solvent thereof, and the like are preferable because such a solvent is friendly to the stability of the column under the HPLC condition, and if it is other organic solvents, it is not preferable from the viewpoint of the lifetime of the column. The water used in the present invention is not particularly limited, and any water that does not affect the purpose of the test may be used, for example, for the purpose of analytical chemistry experiments, analytical laboratory water may be used, specifically, primary water, secondary water and tertiary water may be used, and the primary water is preferred according to the general requirements for preparing standard solutions and stock solutions (see "GBT 6682 + 2008 analytical laboratory water specification and test method").

In a preferred embodiment of the invention, the concentration of the prepared water wheat winteric acid solution is 0.2 mg/mL-0.8 mg/mL, preferably, the concentration is 0.3 mg/mL-0.6 mg/mL. The water-wheat winteric acid can be better and stably stored under the concentration, and the concentration of the stock solution with the concentration is moderate, so that the water-wheat winteric acid is also suitable for continuous dilution and is used for preparing a standard solution for qualitative or quantitative detection in an HPLC experiment.

In a preferred embodiment of the present invention, the alkalizer is not particularly limited, and any alkalizer can be used as long as it is an alkaline substance that does not cause a redox reaction with the wheatstone acid, such as common inorganic bases and organic bases. Examples of the inorganic base include potassium sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide, aluminum hydroxide, lithium hydroxide, magnesium hydroxide, zinc hydroxide, copper hydroxide, iron hydroxide, lead hydroxide, cobalt hydroxide, chromium hydroxide, zirconium hydroxide, nickel hydroxide, ammonium hydroxide, soda ash (anhydrous sodium carbonate), sodium carbonate (monohydrate, heptahydrate, decahydrate), sodium bicarbonate (baking soda), potassium carbonate, and potassium bicarbonate, but are not limited thereto. Examples of the organic base include triethylamine, triethylenediamine (DABCO), DBU, DBN, DMAP, pyridine, N-methylmorpholine, tetramethylethylenediamine, TMG, potassium/sodium tert-butoxide, N-butyllithium, KHMDS, NaHMDS, LDA, trimethylamine, triethanolamine, diethanolamine, monoethanolamine, diisopropylethylamine, and tetramethylammonium hydroxide, but are not limited thereto.

From the viewpoints of basicity, availability, stability and the like, at least one selected from triethylamine, sodium hydroxide, sodium carbonate and sodium hydrogencarbonate is preferable.

In another embodiment of the present invention, a method for improving the stability of a solution of a compound of formula (I) is provided. In a preferred embodiment of the present invention, the alkalizer is at least one selected from the group consisting of triethylamine, sodium hydroxide, sodium carbonate, and sodium hydrogen carbonate. In a preferred embodiment of the invention, the solution of the hordenic acid is adjusted to a pH of 8 to 12, preferably to a pH of 9 to 11.

step S1: taking alkaline solution containing alkalizer and having pH value of 8-12,

step S2: weighing water wheat winteric acid with target content, dissolving in the alkaline solution,

step S3: in the solution obtained in step S2, the alkalizer is supplemented so that the pH of the entire solution is maintained at 8 to 12 and the volume is fixed to the target volume.

The so-called aqueous solution of the present invention is usually an aqueous solution, but is not limited to an aqueous solution, and may be other solutions, and particularly, an aqueous solution, a methanol solution, an acetonitrile solution, or a mixed solution thereof is preferable because such a solution is friendly to the stability of the column under the HPLC conditions, and if it is another organic solvent, it is not preferable from the viewpoint of the lifetime of the column.

In order to reduce the decomposition of the water wheat winteric acid as much as possible, a mode of firstly preparing a solution in an alkaline environment and then dissolving the water wheat winteric acid is adopted. And finally, adjusting the pH value, the concentration and the volume of the solution to the target requirements in a constant volume mode. In a preferred embodiment of the present invention, the concentration of the water content of the ophiopogon acid is controlled to be 0.2 mg/mL-0.8 mg/mL, preferably 0.3 mg/mL-0.6 mg/mL, and the pH value of the solution to be metered in the step S3 is controlled to be 9-11 by using the alkalizer.

Methods for adjusting the concentration and volume are known, and the most common method is a method of fixing the volume by a volumetric flask. Since a good compound stabilizing effect can be obtained in an environment of pH8-12, preferably 9-11, the person skilled in the art has a large degree of freedom in pH adjustment, and thus simultaneous adjustment to a target pH, concentration and volume can be easily achieved in the S3 step.

In a preferred embodiment of the present invention, the alkalizing agent is not particularly limited, and the same examples as those of the alkalizing agent described above can be given. Preferably at least one selected from triethylamine, sodium hydroxide, sodium carbonate and sodium bicarbonate.

In conclusion, based on the method disclosed by the invention, the solution of the water-wheat winteric acid with proper concentration, good stability and low degradation rate can be prepared, the requirement of convenience in analysis and test is met, the consumption of reference substances is greatly reduced, and the cost of the method is controlled.

Examples

The technical solutions of the present invention will be described clearly and completely below, and it should be apparent that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

In the following examples, the degradation rate of the water-wheat winteric acid was determined according to the following formula:

degradation rate (%) - (purity at hour 0-purity at hour N)/hour N.times.100%

In the following examples, the purity of the water wheat winteric acid is detected by high performance liquid chromatography, and the specific analysis method is as follows:

the instrument comprises the following steps: shimadzu LC-20AD with SPD-M20A detector

A chromatographic column: diamonsil PLUS C18(250mm 4.6mm, 5 μm);

mobile phase: a: acetonitrile, B: 0.1% phosphoric acid, gradient elution parameters are given in the table below;

flow rate: 1.0 mL/min;

column temperature: 30 ℃;

sample introduction volume: 5 μ L.

Time (min)	Flow rate (mL/min)	Mobile phase A (%)	Mobile phase B (%)
				0	1.0	5	95
10	1.0	5	95
				15	1.0	30	70
20	1.0	5	95
				25	1.0	5	95

Example 1 (basic 11.21)

Triethylamine is selected as an alkalizer to prepare an alkaline aqueous solution, and the pH value of the alkaline aqueous solution is 11.21 by a pH meter. Selecting high-purity water-wheat winteric acid (batch number is 8574) self-made by Shanghai Shidande Standard substance Co., Ltd, weighing about 6mg of water-wheat winteric acid, placing the water-wheat winteric acid into a 10mL volumetric flask, dissolving a small amount of alkaline aqueous solution, fixing the volume to a scale line, preparing a water-wheat winteric acid solution with the concentration of about 0.6mg/mL, and determining the degradation rate of the water-wheat winteric acid to be 0.03% after storing for 22 hours.

Example 2 (Water)

Selecting high-purity water wheat winteric acid (batch number is 8574) self-made by Shanghai Shidande Standard substance Co., Ltd, weighing about 5mg of water wheat winteric acid, placing the water wheat winteric acid into a 10mL volumetric flask, dissolving a small amount of water, fixing the volume to a scribed line, preparing a water wheat winteric acid solution with the concentration of about 0.5mg/mL, and determining the degradation rate of the water wheat winteric acid to be 1.11% after storing for 8 hours.

Example 3 (basic 10.64)

Sodium carbonate is selected as an alkalizer to prepare an alkaline aqueous solution, and the pH value of the alkaline aqueous solution is 10.64 by a pH meter. Selecting high-purity water-wheat winteric acid (batch number is 8574) self-made by Shanghai Shidande Standard substance Co., Ltd, weighing about 6mg of water-wheat winteric acid, placing the water-wheat winteric acid into a 20mL volumetric flask, dissolving a small amount of alkaline aqueous solution, fixing the volume to a scale line, preparing a water-wheat winteric acid solution with the concentration of about 0.3mg/mL, and determining the degradation rate of the water-wheat winteric acid to be 0% after storing for 22 hours.

Example 4 (basic 8.6)

Sodium bicarbonate is selected as an alkalizer to prepare an alkaline aqueous solution, and the pH value of the aqueous solution is 8.6 by a pH meter. Selecting high-purity water-wheat winteric acid (batch number is 8574) self-made by Shanghai Shidande standard substance Limited company, weighing about 7mg of water-wheat winteric acid, placing the water-wheat winteric acid into a 10mL volumetric flask, dissolving a small amount of alkaline aqueous solution, metering to a scale line, preparing a water-wheat winteric acid solution with the concentration of about 0.7mg/mL, and determining the degradation rate of the water-wheat winteric acid to be 0.07% after the water-wheat winteric acid solution is stored for 21 hours.

Example 5 (methanol)

Selecting high-purity water wheat winteric acid (batch number is 8574) self-made by Shanghai Shidande Standard substance Co., Ltd, weighing about 5mg of water wheat winteric acid, placing the water wheat winteric acid into a 10mL volumetric flask, dissolving a small amount of methanol, fixing the volume to a scribed line, preparing a water wheat winteric acid solution with the concentration of about 0.5mg/mL, and determining the degradation rate of the water wheat winteric acid to be 1.0% after storing for 9 hours.

Example 6 (basic 11.97)

Sodium hydroxide is selected as an alkalizer to prepare an alkaline aqueous solution, and the pH value of the alkaline aqueous solution is 11.97 by a pH meter. Selecting high-purity water-wheat winteric acid (batch number is 8574) self-made by Shanghai Shidande Standard substance Co., Ltd, weighing about 5mg of water-wheat winteric acid, placing the water-wheat winteric acid into a 10mL volumetric flask, dissolving a small amount of alkaline aqueous solution, fixing the volume to a scale line, preparing a water-wheat winteric acid solution with the concentration of about 0.5mg/mL, and determining the degradation rate of the water-wheat winteric acid to be 0.42% after storing for 9 hours.

Example 7 (basic 11)

Triethylamine is selected as an alkalizer to prepare an alkaline aqueous solution, and the pH value of the alkaline aqueous solution is 11 when a pH meter detects the pH value. Selecting high-purity water-wheat winteric acid (batch number is 8574) self-made by Shanghai Shidande Standard substance Co., Ltd, weighing about 5mg of water-wheat winteric acid, placing the water-wheat winteric acid into a 10mL volumetric flask, dissolving a small amount of alkaline aqueous solution, fixing the volume to a scale line, preparing a water-wheat winteric acid solution with the concentration of about 0.5mg/mL, and determining the degradation rate of the water-wheat winteric acid to be 0% after the water-wheat winteric acid solution is stored for 8 hours.

Example 8 (basic 11)

Triethylamine is selected as an alkalizer to prepare an alkaline aqueous solution, and the pH value of the alkaline aqueous solution is 11 when a pH meter detects the pH value. Selecting high-purity water-wheat winteric acid (batch number is 8574) self-made by Shanghai Shidande Standard substance Co., Ltd, weighing about 8mg of water-wheat winteric acid, placing the water-wheat winteric acid into a 10mL volumetric flask, dissolving a small amount of alkaline aqueous solution, fixing the volume to a scale mark, preparing a water-wheat winteric acid solution with the concentration of about 0.8mg/mL, and determining the degradation rate of the water-wheat winteric acid to be 0.41% after storing for 22 hours.

Example 9 (basicity about 9)

Triethylamine is selected as an alkalizer to prepare an alkaline aqueous solution, and the pH value of the alkaline aqueous solution is 9 when a pH meter detects the pH value. Selecting high-purity water-wheat winteric acid (with the batch number of 8574) self-made by Shanghai Shidande Standard substance Co., Ltd, weighing about 5mg of water-wheat winteric acid, placing the water-wheat winteric acid into a 10mL volumetric flask, dissolving a small amount of alkaline aqueous solution, fixing the volume to a scale mark, preparing a water-wheat winteric acid solution with the concentration of about 0.5mg/mL, and determining the degradation rate of the water-wheat winteric acid to be 0.00% after storing for 22 hours.

In the examples, it is known that the stability can be greatly improved under the alkaline condition of pH8-12, and particularly the stability can be well maintained under the condition of pH 10-11. Under the condition that the concentration is 0.3 mg/mL-0.6 mg/mL, if the pH is controlled to be 10-11, no obvious degradation is found under the test conditions of the test.

Example 10 (5% acetonitrile water)

1.8mg of the dried powder was taken out, and 4ml of 5% acetonitrile water was added thereto and dissolved to prepare a 0.45mg/ml solution, and the same solution was examined and analyzed at 0, 2, 4, 6, 24 and 48 hours (the above samples were shown in FIG. 19 from bottom to top), and the sample purity was 98.7%, 92.0%, 90.1%, 88.1%, 86.6% and 85.3% in this order, indicating that the sample was unstable in 5% acetonitrile water.

Example 11 (0.1% phosphoric acid)

1.7mg of the dried powder was taken out, and dissolved in 4ml (0.1% phosphoric acid) of water to prepare a 0.425mg/ml solution, and the same solution was examined and analyzed at 0, 6, and 24 hours (the above samples were sequentially examined from bottom to top in FIG. 20), and the sample purity was 98.7%, 91.2%, and 89.2%, indicating that the sample was unstable in acid water.

In addition, referring to examples 2, 5, 10 and 11, it is known that the hordenic acid is difficult to exist stably in the solvent of the common HPLC standard solution, and especially, the stability is difficult to maintain under the solution condition of the method for testing supplement of the hordenic acid examination item in the pinellia ternate medicinal materials and decoction pieces issued by the national drug administration. The stock solution and the stability method provided by the invention have wide application prospects.

The technical features disclosed above are not limited to the combinations with other features disclosed, and other combinations between the technical features can be performed by those skilled in the art according to the purpose of the invention to achieve the aim of the invention, and various modifications made to the technical scheme of the invention by those skilled in the art without departing from the design spirit of the invention shall fall within the protection scope defined by the claims of the invention.

Claims

1. A standard stock solution of water malted acid, which is characterized in that: the content of the water wheat winteric acid is 0.01 mg/ml-10 mg/ml, and the water wheat winteric acid standard stock solution contains an alkalizer, so that the whole solution is alkaline.

2. The ophiopogon acid standard stock solution of claim 1, wherein: the concentration of the prepared water wheat winteric acid solution is 0.2 mg/mL-0.8 mg/mL, and preferably, the concentration is 0.3 mg/mL-0.6 mg/mL.

3. The ophiopogon acid standard stock solution of claim 1, wherein: the alkalizer is at least one selected from triethylamine, sodium hydroxide, sodium carbonate and sodium bicarbonate.

4. The ophiopogon acid standard stock solution of claim 1, wherein: the standard stock solution of the water-wheat winteric acid has a pH value of 8-12, preferably a pH value of 9-11.

5. A method for improving the stability of a water-wheat winteric acid solution is characterized in that the water-wheat winteric acid solution is adjusted to be alkaline by using an alkalizer.

6. The method for improving the stability of a water wheat winter acid solution according to claim 5, wherein the alkalizer is at least one selected from triethylamine, sodium hydroxide, sodium carbonate and sodium bicarbonate.

7. The method for improving the stability of a solution of hydroapatic acid according to claim 5, wherein the solution of hydroapatic acid is adjusted to a pH of 8 to 12, preferably to a pH of 9 to 11.

8. A preparation method of a water wheat winteric acid solution is characterized by comprising the following steps:

step S2: weighing water maltesic acid with target content, dissolving in the alkaline solution,

9. The method of claim 8, wherein the step of preparing the solution of the compound of formula (I),

the alkalizer is at least one selected from triethylamine, sodium hydroxide, sodium carbonate and sodium bicarbonate,

the solvent of the alkaline solution with the pH value of 8-12 is water, methanol, acetonitrile or any mixture thereof.

10. The method for preparing a solution of water-wheat-winteric acid according to claim 8,

controlling the concentration of the water ophiopogonic acid to be 0.2 mg/mL-0.8 mg/mL, preferably 0.3 mg/mL-0.6 mg/mL,

and (4) controlling the pH value of the solution with the constant volume in the step S3 to be 9-11 by using an alkalizer.