Method for detecting related substances in procaterol hydrochloride oral solution

Abstract

The invention belongs to the field of drug impurity detection and analysis, and particularly relates to a procaterol hydrochloride oral solution related substance detection method, which adopts high performance liquid chromatography, and the chromatographic conditions are as follows: a chromatographic column is an octadecyl silane bonded silica gel chromatographic column; the detection wavelength is 259 + / -5nm; the column temperature is 30-40 DEG C; the sample size is 10 to 100 [mu] l; the mobile phase A is a mixed solution composed of a phosphate buffer solution and methanol according to a volume ratio of (80-95): (5-20), and the pH value is 1.0-1.8; the mobile phase B is methanol; the flow velocity of the mobile phase is 0.3-1.5 ml / min; a gradient elution mode is adopted. The invention provides a novel method for detecting related substances in the procaterol hydrochloride oral solution, which not only can be used for detecting related impurities I, II and III of procaterol hydrochloride, but also can be used for detecting an auxiliary material degradation impurity 5-hydroxymethylfurfural in the procaterol hydrochloride oral solution at the same time, so that the impurity quality of a product is better controlled, and meanwhile, the detection efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the field of drug impurity detection and analysis, and specifically relates to a method for detecting related substances in Procaterol Hydrochloride Oral Solution. Background Art

[0002] Procaterol hydrochloride is a third-generation adrenergic β-receptor stimulant with high selectivity for bronchial smooth muscle β2 receptors. Procaterol hydrochloride oral solution can be used to relieve symptoms such as dyspnea caused by obstructive airway disorders in the following diseases: bronchial asthma, chronic bronchitis, acute bronchitis, and asthmatic bronchitis.

[0003] Related substances are important factors affecting drug safety and therefore need to be strictly controlled. Currently, no pharmacopoeia in any country has included relevant standards for Procaterol Hydrochloride Oral Solution. Although the 2020 edition of the Chinese Pharmacopoeia and the 2018 edition of the Japanese Pharmacopoeia include detection methods for related substances in Procaterol Hydrochloride raw materials, the excipients in Procaterol Hydrochloride Oral Solution are prone to peaking. The two methods in the pharmacopoeia have poor separation effects on the components and low detection efficiency, and cannot meet the testing requirements for preparations.

[0004] In addition, the prescription of Procaterol Hydrochloride Oral Solution contains a high concentration of sucrose solution. During the long-term storage of the product, sucrose will degrade to produce 5-hydroxymethylfurfural. 5-Hydroxymethylfurfural, or 5-HMF, is a five-carbon aromatic aldehyde. Its molecular structure consists of a furan ring, an aldehyde group, and a hydroxymethyl group. It is a small molecule compound generated by the dehydration of monosaccharides such as glucose and fructose through Maillard reaction or caramelization reaction under high temperature, acidity, or the action of microorganisms. It is widely present in medicines with high sugar content (such as injections containing glucose), Chinese medicinal materials (such as Rehmannia glutinosa), and foods (such as dried fruits and honey). 5-HMF has poor stability, is hygroscopic, sensitive to light and air, and is easily decomposed into levulinic acid and formic acid or undergoes polymerization. Literature reports that 5-HMF has toxic effects, may cause thrombophlebitis, trigger and promote abnormal growth of colonic cysts, promote skin cancer, damage human striated muscles and internal organs, has neurotoxicity, can combine with human proteins to produce cumulative poisoning, and has genetic toxicity and mutagenicity. Therefore, it is necessary to reduce the content of 5-HMF in sugar-containing oral solutions as much as possible to improve the safety of clinical medication.

[0005] Patent CN111239287B discloses a method for simultaneously detecting impurities I and III in Procaterol hydrochloride oral solution; Patent CN116879427A discloses a method for simultaneously detecting impurities I, impurity II, and impurity III in Procaterol hydrochloride oral solution; Patent CN113504320A discloses a method for simultaneously determining Procaterol hydrochloride, impurity I, and impurity II.

[0006] However, none of the above patents discloses a method for simultaneously detecting 5-hydroxymethylfurfural in Procaterol Hydrochloride Oral Solution. Therefore, it is necessary to establish a new detection and analysis method for impurities in Procaterol Hydrochloride Oral Solution, which can simultaneously control and detect 5-hydroxymethylfurfural to ensure that the product quality is safe and controllable. Summary of the invention

[0007] The present invention provides a method for detecting related substances in Procaterol Hydrochloride Oral Solution, characterized in that the detection method adopts high performance liquid chromatography, and the chromatographic conditions are:

[0008] The chromatographic column is an octadecylsilane bonded silica gel chromatographic column; the mobile phase A is a mixed solution composed of phosphate buffer and methanol in a volume ratio of 80-95:5-20, with a pH of 1.0-1.8; the mobile phase B is methanol; the mobile phase flow rate is 0.3-1.5 ml / min; the detection wavelength is 259±5 nm; the column temperature is 30-40° C.; the injection volume is 10-100 μl; and a gradient elution method is adopted;

[0009] Wherein, the related substances include impurity I Impurity II Impurity III 5-Hydroxymethylfurfural Moreover, the separation degree of 5-hydroxymethylfurfural is ≥1.5.

[0010] Preferably, the gradient elution is:

[0011]

[0012]

[0013] or,

[0014] Time / min Mobile phase A% Mobile phase B% 0 100 0 10 100 0 25 92 8 55 92 8 56 20 80 61 20 80 62 100 0 75 100 0

[0015] Preferably, the mobile phase A is prepared by dissolving 9 to 12 g of sodium dihydrogen phosphate in 1000 ml of water, and adjusting the pH value to a range of 1.0 to 1.8 with phosphoric acid.

[0016] Preferably, the volume ratio of phosphate buffer to methanol in the mobile phase A is 85-95:5-15, more preferably 90:10.

[0017] Preferably, the pH of the mobile phase A is 1.0 to 1.6, more preferably 1.0 to 1.4, and most preferably 1.2.

[0018] Preferably, the flow rate of the mobile phase is 0.3-1.0 ml / min, more preferably 0.3-0.7 ml / min, most preferably 0.5 ml / min.

[0019] Preferably, the detection wavelength is 259 nm, the column temperature is 30° C., and the injection volume is 100 μl.

[0020] More preferably, the chromatographic conditions of the high performance liquid chromatography are:

[0021] The chromatographic column is an octadecylsilane bonded silica gel chromatographic column;

[0022] Mobile phase A is a mixed solution composed of phosphate buffer and methanol in a volume ratio of 90:10, with a pH of 1.0-1.4; mobile phase B is methanol; the mobile phase flow rate is 0.3-0.7 ml / min; the detection wavelength is 259 nm; the column temperature is 40 °C; the injection volume is 100 μl; gradient elution is adopted, and the gradient elution parameters are set as follows:

[0023] Time / min Mobile phase A% Mobile phase B% 0 100 0 10 100 0 25 92 8 50 92 8 51 20 80 56 20 80 57 100 0 75 100 0

[0024] On the other hand, the present invention provides a method for detecting related substances of Procaterol Hydrochloride Oral Solution, characterized in that it comprises the following steps:

[0025] (1) Prepare reference solution;

[0026] (2) Prepare system suitability solution;

[0027] (3) Test the test solution and record the chromatogram.

[0028] Preferably, the method specifically comprises the following steps:

[0029] (1) Prepare reference solution:

[0030] Take an appropriate amount of Procaterol hydrochloride reference substance, accurately weigh it, dissolve it with mobile phase A and dilute it to make a solution containing about 1.25 μg per 1 ml to obtain the reference substance stock solution. Measure 1.0 ml of the reference substance stock solution, place it in a 25 ml volumetric flask, add 20 ml of sucrose solution, dilute it to the scale with mobile phase A, shake well, and obtain the reference substance solution.

[0031] (2) Prepare system suitability solution:

[0032] Take an appropriate amount of Procaterol hydrochloride reference substance, weigh it accurately, dissolve it in mobile phase A and dilute it to make a solution containing about 5 μg per 1 ml. Take an appropriate amount, heat it in a water bath for 30 minutes, take it out and cool it to room temperature to obtain a system suitability solution.

[0033] (3) Use the above detection method to detect the test solution.

[0034] The present invention has the following advantages: it provides a new method for detecting related substances in Procaterol hydrochloride oral solution. In addition to detecting related impurities I, II and III of Procaterol hydrochloride, the method can also simultaneously detect auxiliary material degradation impurity 5-hydroxymethylfurfural in the Procaterol hydrochloride oral solution, thereby better controlling the impurity quality of the product and improving the detection efficiency.

[0035] The detection method of the present invention has a separation degree of more than 1.5 between the main component, the impurity peak and the auxiliary material peak. The method is simple to operate, has strong specificity and high detection efficiency, and is suitable for the quality control of Procaterol Hydrochloride Oral Solution.

[0036] The detection method provided by the present invention can simultaneously detect related substances (impurity I, impurity II, impurity III) of the Procaterol hydrochloride oral solution, especially the degradation impurity 5-hydroxymethylfurfural, thereby achieving effective control of product quality and further ensuring product safety.

[0037] The detection method provided by the present invention has good specificity, the auxiliary materials do not interfere with the detection of the main components and impurities, the separation degrees among the Procaterol hydrochloride, the impurity peaks and the auxiliary material peaks are all far more than 1.5, and the separation effect is good. At the same time, the method has high detection sensitivity, fast efficiency, good reproducibility and good tolerance. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1a and Figure 1b This is the HPLC chart of the related substance detection method of Procaterol Hydrochloride raw material using the 2020 edition of the "Chinese Pharmacopoeia".

[0039] Figure 2 This is an HPLC chart obtained by using the detection method in Example 1 where mobile phase A is a pH 3.5 phosphate buffer.

[0040] Figure 3 This is an HPLC chart obtained by using the detection method in Example 1 where mobile phase A is a pH 2.8 phosphate buffer.

[0041] Figure 4 This is an HPLC chart obtained by using the detection method in Example 1 where mobile phase A is a pH 2.5 phosphate buffer.

[0042] Figure 5a and Figure 5b They are respectively an HPLC graph and a local magnified graph obtained by the detection method in Example 1 in which the mobile phase A is a pH 1.2 phosphate buffer.

[0043] Figure 6a and Figure 6b They are respectively the HPLC graph and the local magnified graph obtained by the detection method of Example 2.

[0044] Figure 7a HPLC overlay of blank auxiliary material and impurity mixed solution obtained by the detection method of Example 3.

[0045] Figure 7b The HPLC chart of the combined solution of blank auxiliary material + impurity mixed solution obtained by the detection method of Example 3.

[0046] Figure 8a and Figure 8b They are respectively the HPLC graph and the local magnified graph of the test solution obtained by the detection method of Example 3.

[0047] Fig. 9 This is the HPLC chart obtained using the detection method of Example 4. DETAILED DESCRIPTION

[0048] Reference to an embodiment herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0049] Comparative Example 1: Detection Method for Related Substances of Procaterol Hydrochloride in the 2020 Edition of the Chinese Pharmacopoeia

[0050] (1) Chromatographic conditions:

[0051] Chromatographic column: octadecylsilane bonded silica gel

[0052] Mobile phase: phosphate buffer (11.04 g sodium dihydrogen phosphate, add 1000 ml water to dissolve, adjust pH to 3.1 ± 0.05 with phosphoric acid) - methanol (83:17)

[0053] Detection wavelength: 259nm; injection volume: 20μl; column temperature: 25℃; flow rate: 1.0ml / min.

[0054] (2) Preparation of test solution and control solution:

[0055] Take Procaterol hydrochloride oral solution as the test solution.

[0056] Accurately measure 1 ml of the test solution, place it in a 100 ml volumetric flask, dilute to the mark with the mobile phase, shake well, and obtain the reference solution.

[0057] (3) Testing of test solution:

[0058] Take the test solution and perform HPLC analysis under the above chromatographic conditions. Record the chromatogram. The results are shown in Figure 1a and 1b .

[0059] Figure 1a and 1b It shows that after 100 minutes of operation, the auxiliary material peak has not been completely eluted, and there is still an uneluted auxiliary material peak in the next needle, the separation and detection efficiency is low, and the detection sensitivity is low. Therefore, the chromatographic conditions need to be improved.

[0060] Example 1

[0061] (1) Chromatographic conditions:

[0062] Mobile phase A: phosphate buffer with pH values ​​of 3.5, 2.8, 2.5, and 1.2; Mobile phase B: methanol;

[0063] Detection wavelength: 259nm; flow rate: 0.8ml / min; injection volume: 100μl; column temperature: 40°C. The elution gradient is shown in Table 1 below:

[0064] Table 1 Elution gradient parameters of Example 1

[0065]

[0066]

[0067] (2) Prepare blank excipient solution and impurity mixed solution containing Procaterol hydrochloride and impurities I, II and III respectively:

[0068] Blank excipient solution: Take the prescribed amount of blank excipient of this product and place it at 60°C for 30 days to destroy it and produce 5-hydroxymethylfurfural.

[0069] (3) Take blank excipient and impurity mixed solution respectively, perform HPLC analysis under the above chromatographic conditions, record the chromatogram, and the HPLC overlay results of blank excipient and impurity mixed solution are shown in Figure 2 to Figure 5b Among them, peak 1 in the figure is Procaterol hydrochloride, peak 2 is impurity I, peak 3 is impurity II, and peak 4 is impurity III.

[0070] Figure 2 to Figure 4 It was shown that after adjusting the chromatographic conditions, the elution and separation of Procaterol hydrochloride, related impurities and 5-HMF were better, but when the pH of mobile phase A was higher, the excipient peak in the blank excipient significantly interfered with impurity I. Figure 5a to Figure 5bIt shows that lowering the pH of mobile phase A can significantly improve the interference of the excipient peak on impurity I. However, the excipient peaks are still near the peaks of the main component Procaterol Hydrochloride and impurity I. The excipient peaks are close to each other, and the tolerance of the method is easily affected. There is a risk of poor tolerance during repeated use, which may lead to interference. Therefore, the chromatographic conditions need to be further improved.

[0071] Example 2

[0072] On the basis of Example 1, mobile phase A was set to pH 1.2 phosphate buffer, the chromatographic flow rate was adjusted to 0.5 ml / min, the column temperature was 30°C, and other chromatographic conditions and processes were the same as in Example 1. The results are shown in FIG. Figure 6a and Figure 6b Among them, peak 1 in the figure is Procaterol hydrochloride, peak 2 is impurity I, peak 3 is impurity II, and peak 4 is impurity III.

[0073] Figure 6a and Figure 6b The results showed that the detection scheme after optimizing the flow rate and column temperature had no significant effect on the elution and separation of the main component, impurity I, impurity II, and impurity III, and significantly improved the separation of impurity I and adjacent excipient peaks. However, it worsened the separation of the main component Procaterol hydrochloride and adjacent chromatographic peaks, so the chromatographic conditions needed to be further improved.

[0074] Example 3

[0075] On the basis of Example 2, the mobile phase A was adjusted to pH 1.2 phosphate buffer-methanol (90:10), and the elution gradient was adjusted as shown in Table 2 below. The other chromatographic conditions and processes were the same as in Example 1. The chromatogram results are shown in Figure 7a .in, Figure 7a Peak 1 is Procaterol hydrochloride, peak 2 is impurity I, peak 3 is impurity II, and peak 4 is impurity III.

[0076] Table 2 Example 3 elution gradient parameters

[0077] Time / min Mobile phase A% Mobile phase B% 0 100 0 10 100 0 25 92 8 55 92 8 56 20 80 61 20 80 62 100 0 75 100 0

[0078] Take the combined solution of blank excipient solution and impurity mixed solution, analyze it by HPLC under the above chromatographic conditions, and record the chromatogram. The chromatogram results are shown in Figure 7b , the separation data are shown in Table 3. Among them, Figure 7b Peak No. 1 is 5-HMF; Peak No. 2 is Procaterol Hydrochloride; Peak No. 3 is Impurity I; Peak No. 4 is Impurity II; Peak No. 5 is Impurity III.

[0079] Table 3 Figure 7a The separation data of each chromatographic peak in

[0080] Peak number Peak name Separation 1 5-HMF 28.59 2 Procaterol Hydrochloride 4.73 3 Impurity I 18.29 4 Impurity II 2.65 5 Impurity III na

[0081] Take Procaterol Hydrochloride Oral Solution as the test solution, analyze it by HPLC under the above chromatographic conditions, and record the chromatogram. The chromatogram results are shown in Figure 8a and Figure 8b , the separation data are shown in Table 4.

[0082] Table 4 Figure 8b The separation data of each chromatographic peak in

[0083] Peak number Peak name Separation 1 Excipient Peak 1 2.64 2 Procaterol Hydrochloride 4.73 3 Impurity I 2.30 4 Auxiliary material peak 2 NA

[0084] Figure 7a to Figure 8b As shown in the separation data in Tables 3 and 4, under the above chromatographic conditions, the separation between 5-HMF, Procaterol Hydrochloride, impurity I, impurity II and impurity III is much greater than 1.5, and the separation is good; the blank excipient has no interference with the detection of impurity I, impurity II and impurity III, and the separation between impurity I and adjacent excipient peaks reaches 2.30.

[0085] Example 4

[0086] (1) Chromatographic conditions

[0087] Chromatographic column: Octadecylsilane bonded silica gel column Waters XBridge C18 (4.6mm×150mm, 5μm)

[0088] Mobile phase A: phosphate buffer (weigh 11.04 g of anhydrous sodium dihydrogen phosphate, add 1000 ml of water to dissolve, and adjust the pH to 1.2 with phosphoric acid)-methanol (90:10); mobile phase B: methanol;

[0089] Detection wavelength: 259nm; column temperature: 30℃; flow rate: 0.5ml / min; injection volume: 100μl;

[0090] The elution gradient is shown in Table 5 below:

[0091] Table 5 Example 4 elution gradient parameters

[0092] Time / min Mobile phase A% Mobile phase B% 0 100 0 10 100 0 25 92 8 50 92 8 51 20 80 56 20 80 57 100 0 75 100 0

[0093] (2) Preparation of reference solution

[0094] Take an appropriate amount of Procaterol hydrochloride reference substance, accurately weigh it, dissolve and dilute it with mobile phase A to make a solution containing about 1.25μg per 1ml, that is, the reference substance stock solution. Measure 1.0ml of the reference substance stock solution, place it in a 25ml volumetric flask, add 20ml of sucrose solution (take an appropriate amount of sucrose, dissolve and dilute it with water to make a solution containing about 35mg per 1ml), dilute it to the scale with mobile phase A, shake well, and obtain.

[0095] (3) Preparation of system suitability solution

[0096] Take an appropriate amount of Procaterol hydrochloride reference substance, weigh it accurately, dissolve it in mobile phase A and dilute it to make a solution containing about 5 μg per 1 ml, take an appropriate amount, heat it in a water bath for 30 minutes, take it out and cool it to room temperature, and then destroy it to produce impurities I, II and III.

[0097] (4) Testing of test solution

[0098] Take the Procaterol hydrochloride oral solution and perform HPLC analysis under the above chromatographic conditions. Record the chromatogram. The results are shown in Fig. 9 .

[0099] Fig. 9 It was shown that under the chromatographic conditions, not only Procaterol Hydrochloride, impurity I, impurity II, impurity III and 5-hydroxymethylfurfural could be detected simultaneously, but also the separation effects among the main component, impurity peak and auxiliary material peak were good. The auxiliary materials had no interference in the detection of each component, the separation degrees were far more than 1.5, and the method had good reproducibility and tolerance.

[0100] Example 5

[0101] (1) Chromatographic conditions: The pH values ​​of mobile phase A were adjusted to 1.0, 1.2, and 1.4, respectively. Other conditions were the same as those in Example 4.

[0102] (2) Sample preparation: Impurity stock solution: Weigh about 6 mg of each of the impurity I, impurity II, and impurity III reference substances into a 100-ml volumetric flask, dissolve in methanol and dilute to the mark, shake well, measure 1 ml, place in a 50-ml volumetric flask, dilute to the mark with mobile phase A, shake well, and obtain.

[0103] (3) Test solution: Take 20 ml of Procaterol hydrochloride oral solution, add 1 ml of the above impurity stock solution, mix well, and obtain the product.

[0104] (4) Take the test solution and perform HPLC analysis under the above chromatographic conditions, and record the test results as shown in Table 6 below.

[0105] Table 6 Separation data of mobile phase A at different pH

[0106]

[0107] Example 6

[0108] (1) Chromatographic conditions: The chromatographic flow rates were adjusted to 0.3, 0.5, and 0.7 ml / min, respectively. Other conditions were the same as those in Example 4.

[0109] (2) Sample preparation: Impurity stock solution: Weigh about 6 mg of each of the impurity I, impurity II, and impurity III reference substances into a 100-ml volumetric flask, dissolve in methanol and dilute to the mark, shake well, measure 1 ml, place in a 50-ml volumetric flask, dilute to the mark with mobile phase A, shake well, and obtain.

[0110] (3) Test solution: Take 20 ml of Procaterol hydrochloride oral solution, add 1 ml of the above impurity stock solution, mix well, and obtain the product.

[0111] (4) Take the test solution and perform HPLC analysis under the above chromatographic conditions, and record the test results as shown in Table 7 below.

[0112] Table 7 Separation data at different flow rates

[0113]

[0114] The results of Examples 5 and 6 show that the detection method of the present invention still meets the requirements for the detection and separation of impurities I, impurity II, impurity III and 5-hydroxymethylfurfural in Procaterol Hydrochloride Oral Solution when the chromatographic conditions of the detection method vary by ±0.2 in the pH value of the mobile phase A and the flow rate of the mobile phase varies by ±0.2 ml / min. The method has good tolerance and strong operability.

[0115] Although the present invention is described in detail with reference to the above embodiments, it is obvious to those skilled in the art through this disclosure that various changes or modifications may be made to the present invention without departing from the principle and spirit of the present invention defined by the claims. Therefore, the detailed description of the embodiments of the present disclosure is only used to explain, not to limit the present invention, but the scope of protection is limited by the content of the claims.

Claims

1. A method for detecting impurities in Procaterol Hydrochloride Oral Solution, characterized in that: The detection method adopts high performance liquid chromatography, and the chromatographic conditions are: The chromatographic column is an octadecylsilane bonded silica gel chromatographic column; the detection wavelength is 259±5nm; the column temperature is 30-40°C; the injection volume is 10-100μl; the mobile phase A is a mixed solution composed of phosphate buffer and methanol in a volume ratio of 80-95:5-20, with a pH of 1.0-1.8; the mobile phase B is methanol; the mobile phase flow rate is 0.3-1.5ml / min; a gradient elution method is adopted; Wherein, the impurity is impurity I Impurity II Impurity III 5-Hydroxymethylfurfural Moreover, the separation degree of 5-hydroxymethylfurfural is ≥1.

5.

2. The method for detecting related substances in Procaterol Hydrochloride Oral Solution according to claim 1, characterized in that: The gradient elution is: or, 3. The method for detecting related substances in Procaterol Hydrochloride Oral Solution according to claim 2, characterized in that: The mobile phase A is prepared by adding 9-12 g of sodium dihydrogen phosphate into 1000 ml of water to dissolve the mixture, and adjusting the pH value to a range of 1.0-1.8 with phosphoric acid.

4. The method for detecting related substances in Procaterol Hydrochloride Oral Solution according to claim 2, characterized in that: The volume ratio of phosphate buffer to methanol in the mobile phase A is 85-95:5-15.

5. The method for detecting related substances of Procaterol Hydrochloride Oral Solution according to claim 2, characterized in that: The pH of the mobile phase A is 1.0-1.

6.

6. The method for detecting impurities in Procaterol Hydrochloride Oral Solution according to claim 2, characterized in that: The flow rate of the mobile phase is 0.3-1.0 ml / min.

7. The method for detecting impurities in Procaterol Hydrochloride Oral Solution according to claim 2, characterized in that: The column temperature was 30°C.

8. A method for detecting related substances in Procaterol Hydrochloride Oral Solution, characterized in that: The following steps are involved: (1) Prepare reference solution; (2) Prepare system suitability solution; (3) Determine the test solution using the method for detecting related substances of Procaterol Hydrochloride Oral Solution as described in any one of claims 1 to 7, and record the chromatogram.

9. The method for detecting impurities in Procaterol Hydrochloride Oral Solution according to claim 8, characterized in that: The following steps are involved: (1) Prepare reference solution: Take an appropriate amount of Procaterol hydrochloride reference substance, accurately weigh it, dissolve it with mobile phase A and dilute it to make a solution containing about 1.25 μg per 1 ml to obtain the reference substance stock solution. Measure 1.0 ml of the reference substance stock solution, place it in a 25 ml volumetric flask, add 20 ml of sucrose solution, dilute it to the scale with mobile phase A, shake well, and obtain the reference substance solution. (2) Prepare system suitability solution: Take an appropriate amount of Procaterol hydrochloride reference substance, weigh it accurately, dissolve it in mobile phase A and dilute it to make a solution containing about 5 μg per 1 ml. Take an appropriate amount, heat it in a water bath for 30 minutes, take it out and cool it to room temperature to obtain a system suitability solution. (3) Test the test solution.

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