An oral solution of cetirizine hydrochloride, preparation process and use

Abstract

The present invention belongs to the technical field of pharmaceutical preparations, and particularly relates to an oral solution of cetirizine hydrochloride, a preparation process and uses thereof. The oral solution of cetirizine hydrochloride of the present invention is composed of cetirizine hydrochloride, nitidine chloride and pharmaceutically acceptable excipients. By optimizing the prescription components and the preparation process, on the one hand, the therapeutic effect on allergic rhinitis is improved, and on the other hand, the drowsiness side effect of cetirizine hydrochloride is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of pharmaceutical preparations, and particularly relates to an oral solution of cetirizine hydrochloride, a preparation process and uses thereof. Background Art

[0002] Disclosing the information of this background art section is only intended to increase the understanding of the overall background of the present invention, and is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Allergic diseases are caused by the immune system's abnormal reaction to certain substances (allergens), including pollen allergy, food allergy, and asthma, etc. Common symptoms include sneezing, runny nose, itching, and rashes.

[0004] As a second-generation antihistamine, cetirizine hydrochloride mainly selectively blocks histamine H1 receptors and inhibits allergic reactions caused by histamine, such as itching, nasal congestion, and runny nose. It can relieve the symptoms of allergic rhinitis, urticaria, and other allergic skin diseases. The mechanism of action of cetirizine hydrochloride is related to reducing the biological effects of histamine in the body. Clinically, it is used for: (1) Allergic rhinitis: to relieve the symptoms of seasonal allergic rhinitis (such as pollen allergy) and perennial allergic rhinitis; (2) Urticaria: effectively relieve the symptoms of urticaria caused by allergy, including itching and skin redness and swelling; (3) Allergic conjunctivitis: to relieve the eye symptoms caused by allergy, such as eye itching and tearing.

[0005] Chinese Patent with publication number CN103463089A discloses an oral solution of cetirizine hydrochloride, which includes cetirizine hydrochloride, mannitol, hydroxypropyl cellulose, and water, masking the strong bitter taste of the active ingredient cetirizine, improving the stability of the oral solution, reducing the chemical degradation and toxic side effects of cetirizine, reducing the molecular aggregation phenomenon of the active ingredient, reducing the use risk, and improving the safety of medication.

[0006] Chinese Patent with publication number CN115770214A discloses an oral solution containing cetirizine hydrochloride, which is made from the following raw materials and excipients in parts by weight: 0.8 - 1.2 parts of cetirizine hydrochloride, 200 - 300 parts of glycerol, 100 - 200 parts of propylene glycol, 100 - 500 parts of stabilizer, 0.2 - 0.6 parts of flavoring agent, 1 - 2 parts of methylparaben, 0.08 - 0.12 parts of cherry essence, 0.8 - 1.2 parts of glacial acetic acid, 3 - 5 parts of sodium acetate, 3 - 5 parts of sodium acetate, the initial added water amount is 10% - 30% (W / V), and finally add an appropriate amount of purified water to make up to 1L.

[0007] Nitidine chloride is an alkaloid extracted from the dried roots of Zanthoxylum nitidum, a plant of the genus Zanthoxylum in the Rutaceae family. It appears as pale yellow or light green needle-shaped crystals and is soluble in methanol, ethanol, and water. Currently, nitidine chloride has been reported to have various pharmacological effects, mainly including: antitumor effect, anti-inflammatory effect, analgesic effect, cardiovascular system effect, and antifungal effect.

[0008] Currently, there is no prior art on the combined use of cetirizine hydrochloride and nitidine chloride. Summary of the Invention

[0009] In the prior art, cetirizine hydrochloride has a relatively large drowsiness side effect and the anti-allergy effect needs to be improved. To overcome the deficiencies of the prior art, the present invention provides an oral liquid of cetirizine hydrochloride with good anti-allergy effect, small side effects, and stable content.

[0010] The formula of the oral liquid of cetirizine hydrochloride is calculated by mass fraction as follows: cetirizine hydrochloride 0.05% - 0.5%, nitidine chloride 0.2% - 0.8%, glycerol 1.5% - 2.5%, cholesterol 0.8% - 3.2%, preservative 0.01% - 0.2%, flavoring agent 0.01% - 1.0%, appropriate amount of buffer solution, and water.

[0011] Further, the buffer solution is selected from at least one of phosphate buffer solution, carbonate buffer solution, and citrate buffer solution. The preservative is selected from at least one of benzalkonium bromide, sodium benzoate, and potassium sorbate. The flavoring agent is selected from at least one of sucrose, fructose, and aspartame.

[0012] The preparation method of the above-mentioned oral liquid of cetirizine hydrochloride includes the following steps:

[0013] (1) Dissolve glycerol and cholesterol in an appropriate amount of water, heat in a water bath at 32°C - 43°C for 1.5 - 3.5 h, cool, and ultrasonicate to obtain a biphasic system;

[0014] (2) Dissolve nitidine chloride in the biphasic system, ultrasonicate, add cetirizine hydrochloride, adjust the pH to 4.0 - 6.5 with an appropriate amount of buffer solution, preservative, and flavoring agent, mix well, filter, and add water to the full volume to obtain the oral liquid of cetirizine hydrochloride.

[0015] The present invention utilizes the hydrophobic property of cholesterol to help dissolve nitidine chloride, which is poorly soluble in water. Cholesterol is a molecule with weak amphiphilic characteristics, mainly hydrophobic, but its molecule contains a hydroxyl (-OH) group, making it hydrophilic to some extent. However, due to its weak hydrophilicity, an appropriate amount of glycerol is added. Glycerol and cholesterol act together to form micelles or emulsion particles, which are used as a solubilization system to improve the solubility of nitidine chloride in the system. And through accelerated tests, it is also proved that it can make nitidine chloride more stable in the solution.

[0016] The present invention also uses animal experiments to prove the use of the above-mentioned cetirizine hydrochloride oral solution in the preparation of anti-allergy drugs.

[0017] Compared with the prior art, the technical effect of the present invention lies in:

[0018] The present invention explores the combined use effect of cetirizine hydrochloride and nitidine chloride. Through the synergistic effect of the two drugs, the anti-allergy effect can be enhanced, and at the same time, the drowsiness side effect caused by a single drug can be reduced. In addition, since nitidine chloride is a poorly soluble substance, the present invention formulates a glycerol-cholesterol solubilization system to promote the dissolution of nitidine chloride in the solution and also improves the stability of the cetirizine hydrochloride oral solution. Description of the Drawings

[0019] Figure 1 : Statistical analysis of the allergic rhinitis symptom scores of rats in each group.

[0020] Figure 2 : IgE content levels in the sera of rats in each group.

[0021] Figure 3 : OVA-IgE content levels in the sera of rats in each group.

[0022] Figure 4 : Statistical analysis of the average daily sleep duration of rats in each group during drug administration.

[0023] Figure 5 : Changes in the content of cetirizine hydrochloride in the cetirizine hydrochloride oral solutions of Examples 1-5 and Comparative Examples 4-5 during the accelerated experiment.

[0024] Figure 6 : Changes in the content of nitidine chloride in the cetirizine hydrochloride oral solutions of Examples 1-5 and Comparative Examples 4-5 during the accelerated experiment. Detailed Embodiments

[0025] In order to make the objectives and technical solutions of the present invention clearer, the following further describes the present invention with reference to the embodiments. However, the protection scope of the present invention is not limited to these embodiments, and the embodiments are only used to explain the present invention. Those skilled in the art should understand that any changes or equivalent substitutions that do not deviate from the concept of the present invention are included in the protection scope of the present invention.

[0026] Example 1 Cetirizine Hydrochloride Oral Solution

[0027] Formula:

[0028]

[0029]

[0030] Preparation method:

[0031] (1) Dissolve glycerol and cholesterol in an appropriate amount of water, heat in a water bath at 37 °C for 2.5 h, cool, and ultrasonicate to obtain a biphasic system;

[0032] (2) Dissolve nitidine chloride in the biphasic system, ultrasonicate, add cetirizine hydrochloride, adjust the pH to 5.0 with an appropriate amount of buffer solution, add preservatives and flavoring agents, mix well, filter, and add water to the full volume to obtain cetirizine hydrochloride oral solution.

[0033] Example 2 Cetirizine Hydrochloride Oral Solution

[0034] Formulation:

[0035]

[0036] Preparation method:

[0037] (1) Dissolve glycerol and cholesterol in an appropriate amount of water, heat in a water bath at 39 °C for 1.5 h, cool, and ultrasonicate to obtain a biphasic system;

[0038] (2) Dissolve nitidine chloride in the biphasic system, ultrasonicate, add cetirizine hydrochloride, adjust the pH to 4.5 with an appropriate amount of buffer solution, add preservatives and flavoring agents, mix well, filter, and add water to the full volume to obtain cetirizine hydrochloride oral solution.

[0039] Example 3 Cetirizine Hydrochloride Oral Solution

[0040] Formulation:

[0041]

[0042] Preparation method:

[0043] (1) Dissolve glycerol and cholesterol in an appropriate amount of water, heat in a water bath at 35 °C for 3.5 h, cool, and ultrasonicate to obtain a biphasic system;

[0044] (2) Dissolve nitidine chloride in the biphasic system, ultrasonicate, add cetirizine hydrochloride, adjust the pH to 5.5 with an appropriate amount of buffer solution, add preservatives and flavoring agents, mix well, filter, and add water to the full volume to obtain cetirizine hydrochloride oral solution.

[0045] Example 4 Cetirizine Hydrochloride Oral Solution

[0046] Formulation:

[0047]

[0048] Preparation method:

[0049] (1) Dissolve glycerol and cholesterol in an appropriate amount of water, heat in a water bath at 43 °C for 2.5 h, cool, and ultrasonicate to obtain a biphasic system;

[0050] (2) Dissolve nitidine chloride in the biphasic system, ultrasonicate, add cetirizine hydrochloride, adjust the pH to 4.0 with an appropriate amount of buffer solution, add preservatives and flavoring agents, mix well, filter, and add water to the full volume to obtain cetirizine hydrochloride oral liquid.

[0051] Example 5 Cetirizine Hydrochloride Oral Liquid

[0052] Formulation:

[0053]

[0054] Preparation method:

[0055] (1) Dissolve glycerol and cholesterol in an appropriate amount of water, heat in a water bath at 32 °C for 2.5 h, cool, and ultrasonicate to obtain a biphasic system;

[0056] (2) Dissolve nitidine chloride in the biphasic system, ultrasonicate, add cetirizine hydrochloride, adjust the pH to 6.5 with an appropriate amount of buffer solution, add preservatives and flavoring agents, mix well, filter, and add water to the full volume to obtain cetirizine hydrochloride oral liquid.

[0057] Comparative Example 1 Cetirizine Hydrochloride Oral Liquid

[0058] Formulation:

[0059]

[0060]

[0061] Preparation method:

[0062] (1) Dissolve glycerol and cholesterol in an appropriate amount of water, heat in a water bath at 37 °C for 2.5 h, cool, and ultrasonicate to obtain a biphasic system;

[0063] (2) Add cetirizine hydrochloride to the biphasic system, adjust the pH to 5.0 with an appropriate amount of buffer solution, add preservatives and flavoring agents, mix well, filter, and add water to the full volume to obtain cetirizine hydrochloride oral liquid.

[0064] Comparative Example 2 Cetirizine Hydrochloride Oral Liquid

[0065] Formulation:

[0066]

[0067] Preparation method:

[0068] (1) Dissolve glycerol and cholesterol in an appropriate amount of water, heat in a water bath at 37 °C for 2.5 h, cool, and ultrasonicate to obtain a biphasic system;

[0069] (2) Dissolve ethoxychelerythrine in a biphasic system, sonicate, add cetirizine hydrochloride, adjust the pH to 5.0 with an appropriate buffer solution, add preservatives and flavoring agents, mix well, filter, and add water to the full volume to obtain cetirizine hydrochloride oral solution.

[0070] Comparative Example 3 Cetirizine Hydrochloride Oral Solution

[0071] Formula:

[0072]

[0073]

[0074] Preparation method:

[0075] (1) Dissolve glycerol and cholesterol in an appropriate amount of water, heat in a water bath at 37 °C for 2.5 h, cool, and sonicate to obtain a biphasic system;

[0076] (2) After processing zanthoxylum nitidum, grind it into powder, add it to the biphasic system, sonicate, add cetirizine hydrochloride, adjust the pH to 5.0 with an appropriate buffer solution, add preservatives and flavoring agents, mix well, add water to the full volume to obtain cetirizine hydrochloride suspension oral solution.

[0077] Comparative Example 4 Cetirizine Hydrochloride Oral Solution

[0078] Formula:

[0079]

[0080] Preparation method:

[0081] Dissolve glycerol in an appropriate amount of water, heat in a water bath at 37 °C for 2.5 h, cool, sonicate, add nitidine chloride and sonicate, add cetirizine hydrochloride, adjust the pH to 5.0 with an appropriate buffer solution, add preservatives and flavoring agents, mix well, filter, and add water to the full volume to obtain cetirizine hydrochloride oral solution.

[0082] Comparative Example 5 Cetirizine Hydrochloride Oral Solution

[0083] Formula:

[0084]

[0085]

[0086] Preparation method:

[0087] Cholesterol was mixed with an appropriate amount of water, heated in a water bath at 37 °C for 2.5 h, cooled, sonicated, nitidine chloride was added, sonicated again, cetirizine hydrochloride was added, and the pH was adjusted to 5.0 with an appropriate amount of buffer solution. A preservative and a flavoring agent were added, mixed well, filtered, and water was added to make up the volume to obtain the cetirizine hydrochloride oral solution.

[0088] Therapeutic effect of the cetirizine hydrochloride oral solution of the present invention on rats with allergic rhinitis model

[0089] Experimental animals:

[0090] SD rats, SPF grade, 180 - 220 g, experimental animal license number: SYXK(Shandong)20180008, adaptively fed under standard conditions for 1 week before the experiment.

[0091] Drugs and dosage:

[0092] The cetirizine hydrochloride oral solutions obtained in Examples 1, 2, and 3 of the present invention, the cetirizine hydrochloride oral solutions obtained in Comparative Examples 1, 2, and 3, and the cetirizine hydrochloride oral solution (National Drug Approval Number H20103265).

[0093] Dosage: Calculated as cetirizine hydrochloride, 0.9 mg / kg.

[0094] Model establishment and grouping:

[0095] An ovalbumin (OVA) - sensitized model was established. A number of rats were taken. On the first day, 0.5 ml of sterile physiological saline containing 10 μg OVA and 1 mg aluminum hydroxide gel was intraperitoneally injected for basic sensitization. On the fifth day, 0.5 ml of sterile physiological saline containing 10 μg OVA was intraperitoneally injected for booster sensitization. Starting from the sixth day, 50 μl of 2 mg / ml OVA was used to drip - nose the rats once a day for 14 consecutive days to stimulate the rats. The successfully modeled rats were divided into a model group, an Example 1 group, an Example 2 group, an Example 3 group, a Comparative Example 1 group, a Comparative Example 2 group, a Comparative Example 3 group, and a commercially available group, with 10 rats in each group. The blank group was pseudo - sensitized and stimulated with sterile physiological saline according to the same process, with 10 rats.

[0096] Drug administration method:

[0097] The rats in each drug - administration group were given the corresponding drugs by gavage, and the blank group and the model group were given an equal amount of physiological saline by gavage, once a day for 7 consecutive days.

[0098] Statistical processing:

[0099] SPSS 22.0 software was used to statistically analyze the obtained data. Measurement data were expressed as (x ± s). One - way ANOVA was used for comparison among multiple groups, and independent - sample T - test was used for comparison between two groups. P < 0.05 was considered statistically significant.

[0100] Observation indicators:

[0101] Behavioral observation of allergic rhinitis in rats

[0102] Observe the symptoms of allergic rhinitis in rats of each group, give scores and statistics. The scoring criteria are nasal itching, nasal discharge, sneezing, tearing, and eye itching symptoms, and each symptom is scored 2 points.

[0103] As Figure 1 shown, compared with the model group, there were statistically significant differences in the Example 1 group, Example 2 group, and Example 3 group (P < 0.01). Compared with the Comparative Example 3 group, there were statistically significant differences in the Example 1 group, Example 2 group, and Example 3 group (P < 0.01). Compared with the commercial group, there were statistically significant differences in the Example 1 group, Example 2 group, and Example 3 group (P < 0.01). It shows that the combined use of cetirizine hydrochloride and nitidine chloride can significantly relieve the symptoms of allergic rhinitis in rats, and the effect is better than that of using cetirizine hydrochloride alone.

[0104] Serum IgE, OVA-IgE content

[0105] The IgE and OVA-IgE contents in serum are closely related to allergic rhinitis. IgE is an important marker of allergic reactions, and its elevated level is usually associated with allergic diseases (such as allergic rhinitis). Using ovalbumin (OVA) as an allergen, the production of specific IgE indicates sensitivity to this allergen. High levels of IgE and OVA-IgE usually mean more severe allergic reactions and rhinitis symptoms.

[0106] Figure 2 is the IgE content level in the serum of rats in each group, Figure 3 is the OVA-IgE content level in the serum of rats in each group. Compared with the model group, there were statistically significant differences in the Example 1 group, Example 2 group, and Example 3 group (P < 0.01). Compared with the Comparative Example 3 group, there were significant differences (P < 0.01). Compared with the commercial group, there were statistically significant differences in the Example 1 group, Example 2 group, and Example 3 group (P < 0.01). Since ethoxychelerythrine is one of the substances simultaneously determined with nitidine chloride in Zanthoxylum nitidum, it is speculated that there may be similarities in their chemical structures or common points in their medicinal values. In Comparative Example 2, ethoxychelerythrine was used instead of nitidine chloride in combination with cetirizine hydrochloride to explore its effect on treating allergic rhinitis, and it was found that its effect was far less than that of the combination of cetirizine hydrochloride and nitidine chloride.

[0107] Side effect statistics

[0108] Cetirizine hydrochloride is a second-generation antihistamine. On the one hand, although cetirizine hydrochloride has relatively high selectivity, it can still penetrate the blood-brain barrier and bind to the histamine H1 receptor in the central nervous system, resulting in sedation. On the other hand, cetirizine hydrochloride may have slight anticholinergic activity, which may also cause drowsiness.

[0109] Figure 4 Statistics of the average daily sleep duration of rats in each group. There was no significant difference in the average daily sleep duration of rats in Example 1-3 groups compared with the blank group, and there were significant differences compared with the commercial group and Comparative Example 1-3 groups respectively, P < 0.01. It shows that the cetirizine hydrochloride oral solution of the present invention alleviates and reduces the drowsiness side effect of cetirizine hydrochloride.

[0110] Stability study of cetirizine hydrochloride oral solution

[0111] The cetirizine hydrochloride oral solutions of Examples 1-5 and the cetirizine hydrochloride oral solutions of Comparative Examples 4-5 were packaged according to the commercial packaging and subjected to an accelerated test under the conditions of a temperature of 40°C ± 2°C and a relative humidity of 75% ± 5%. Samples were taken on the 1st day, the end of the 2nd month, the end of the 3rd month, and the end of the 6th month respectively, and the contents of cetirizine hydrochloride and nitidine chloride were determined.

[0112] The content determination of cetirizine hydrochloride was carried out according to the high performance liquid chromatography method (General Principles 0512) in the Chinese Pharmacopoeia 2020 Edition.

[0113] Test solution: Accurately measure an appropriate amount of this product and quantitatively dilute it with water to prepare a solution containing about 50 μg of cetirizine hydrochloride per 1 ml. Reference solution: Take an appropriate amount of cetirizine hydrochloride reference substance, accurately weigh it, dissolve it in water and quantitatively dilute it to prepare a solution containing about 50 μg per 1 ml. Chromatographic conditions: Use octadecylsilane chemically bonded silica gel as the filler; use 0.1 mol / L potassium dihydrogen phosphate solution (adjust the pH value to 3.7 with phosphoric acid)-acetonitrile (60:40) as the mobile phase; the detection wavelength is 232 nm; the injection volume is 20 μl. The system suitability requirements are that the number of theoretical plates calculated according to the cetirizine peak is not less than 2000. Determination method: Accurately measure the test solution and the reference solution, inject them into the liquid chromatograph respectively, and record the chromatogram. Calculate according to the external standard method with the peak area.

[0114] The content determination of nitidine chloride was carried out according to the high performance liquid chromatography method (General Principles 0512) in the Chinese Pharmacopoeia 2020 Edition.

[0115] Chromatographic conditions and system suitability test: Use octadecylsilane chemically bonded silica gel as the filler; use acetonitrile as mobile phase A and 0.1% formic acid-triethylamine (pH 4.5) as mobile phase B, and perform gradient elution according to the regulations in Table 1; the detection wavelength is 273 nm. The number of theoretical plates calculated according to the nitidine peak should be not less than 2500.

[0116] Table 1 Elution Procedure

[0117]

[0118]

[0119] Preparation of reference solution: Weigh an appropriate amount of nitidine chloride reference substance accurately, dissolve it in 70% methanol to prepare a solution containing 50 μg per 1 ml. Preparation of test solution: Weigh this product accurately, place it in a stoppered conical flask, add 20 ml of 70% methanol, ultrasonically treat it (power 200 W, frequency 59 kHz) for 30 minutes, cool it, filter, transfer the filtrate to a 50-ml volumetric flask. Add another 20 ml of 70% methanol to the filter residue and filter paper, ultrasonically treat it in the same way for 30 minutes, cool it, filter, transfer the filtrate to the same volumetric flask, wash it twice with an appropriate amount of 70% methanol, combine the washing solutions into the same volumetric flask, add 70% methanol to the scale, shake well to obtain the solution. Assay method: Accurately pipette 10 μl of the reference solution and the test solution respectively, inject them into the liquid chromatograph for determination to obtain the result.

[0120] Figure 5 For the content change of cetirizine hydrochloride in the oral solution of cetirizine hydrochloride in Examples 1 - 5 and Comparative Examples 4 - 5 during the accelerated test. Figure 6 For the content change of nitidine chloride in the oral solution of cetirizine hydrochloride in Examples 1 - 5 and Comparative Examples 4 - 5 during the accelerated test. Cholesterol is a molecule with weak amphiphilic characteristics, mainly hydrophobic, but it contains a hydroxyl (-OH) group in its molecule, making it hydrophilic to some extent. Therefore, the hydrophobic property of cholesterol in the present invention can help dissolve nitidine chloride, which is poorly soluble in water. However, due to its weak hydrophilicity, adding an appropriate amount of glycerol and cholesterol as a solubilization system together will form micelles or emulsion particles. Through a large number of experiments, it is proved that this method can make nitidine chloride more stable in the solution.

Claims

1. A cetirizine hydrochloride oral solution, characterized in that: The formula of the cetirizine hydrochloride oral solution is: 0.05%-0.5% of cetirizine hydrochloride, 0.2%-0.8% of nitidine chloride, 1.5%-2.5% of glycerol, 0.8%-3.2% of cholesterol, 0.01%-0.2% of preservative, 0.01%-1.0% of flavoring agent, appropriate amount of buffer solution and water.

2. The cetirizine hydrochloride oral solution according to claim 1, characterized in that: The formula of the cetirizine hydrochloride oral solution is: 0.1% of cetirizine hydrochloride, 0.5% of nitidine chloride, 2.0% of glycerol, 1.8% of cholesterol, 0.05% of preservative, 0.5% of flavoring agent, appropriate amount of buffer solution and water.

3. The cetirizine hydrochloride oral solution according to claim 1, characterized in that: The buffer solution is selected from at least one of a phosphate buffer solution, a carbonate buffer solution, and a citrate buffer solution.

4. The cetirizine hydrochloride oral solution according to claim 3, characterized in that: The buffer solution is a phosphate buffer solution.

5. The cetirizine hydrochloride oral solution according to claim 1, characterized in that: The preservative is selected from at least one of benzalkonium bromide, sodium benzoate and potassium sorbate.

6. The cetirizine hydrochloride oral solution according to claim 5, characterized in that: The preservative is sodium benzoate.

7. The cetirizine hydrochloride oral solution according to claim 1, characterized in that: The flavor corrective is selected from at least one of sucrose, fructose and aspartame.

8. The cetirizine hydrochloride oral solution according to claim 7, characterized in that: The flavoring agent is aspartame.

9. A method for preparing the cetirizine hydrochloride oral solution according to claim 1, characterized in that: The preparation method comprises the following steps: (1) Dissolve glycerol and cholesterol in an appropriate amount of water, heat in a water bath at 32°C to 43°C for 1.5 to 3.5 hours, cool, and sonicate to obtain a multiphase system; (2) Dissolve nitidine chloride in the multiphase system, sonicate, add cetirizine hydrochloride, an appropriate amount of buffer solution, a preservative, and a flavoring agent, mix well, filter, and add water to the total amount to obtain a cetirizine hydrochloride oral solution.

10. The preparation method according to claim 9, wherein the pH of the buffer solution is 4.0 to 6.

5. The preparation method according to claim 9 , wherein the pH of the buffer solution is 4.5 to 5.

5.

12. The preparation method according to claim 9, wherein the water bath heating temperature is 37±2°C.

13. Use of the cetirizine hydrochloride oral solution according to claim 1 in the preparation of antiallergic drugs.

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