A cimetidine injection composition and a production process thereof

Abstract

The application provides a cimetidine injection composition and a production process thereof, and belongs to the technical field of pharmaceutical preparations, and solves the technical problems of complex prescription, strong sensitization of auxiliary materials, strong irritation and insufficient control of genotoxic impurities of the existing cimetidine injection. The cimetidine injection composition and the production process thereof, the composition is composed of cimetidine, hydrochloric acid solution, sodium chloride and water for injection, the pH value is 5.0-6.8, the molar concentration of osmotic pressure is 280-320 mOsmol / kg, and 0.2 g of cimetidine is contained in every 2 ml. The application replaces the antioxidant by full nitrogen protection, establishes a high-sensitivity LC-MS / MS method for detecting N-nitroso cimetidine, and shows that the muscle irritation of non-clinical safety is better than that of the commercial preparation, the allergic and hemolytic reactions are both negative, the cytotoxicity is 0-1 level, and the unification of prescription simplification, safety improvement and quality control is realized.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical preparation technology, and relates to a cimetidine injection composition, particularly a cimetidine injection composition and its manufacturing process. Background Technology

[0002] Cimetidine, also known as cimetidine, is a selective H2 receptor antagonist that inhibits basal and nocturnal gastric acid secretion, as well as gastric acid secretion stimulated by histamine, pentagastrin, insulin, and food. Clinically, it is widely used to treat duodenal ulcers, gastric ulcers, upper gastrointestinal bleeding, reflux esophagitis, gastrinoma, and to prevent stress ulcers.

[0003] Cimetidine injection is one of the commonly used dosage forms in clinical practice. Currently, 11 companies in China hold licenses for cimetidine injection and have passed or are deemed to have passed the generic drug quality and efficacy consistency evaluation. However, existing cimetidine injections generally have the following technical problems: First, the formulation is complex, with a wide variety of excipients. In existing technologies, to ensure the stability of cimetidine injection, antioxidants (such as sodium thiosulfate, sodium sulfite, ascorbic acid, sodium metabisulfite, sodium bisulfite, etc.) and metal chelating agents (such as EDTA-2Na) are typically added. For example, CN102670496A discloses that cimetidine injection contains 0.2–0.4 g of antioxidant and 0.2–1.0 g of chelating agent per 100 ml. The addition of multiple excipients not only increases the complexity of the formulation but also raises production costs and quality control difficulties.

[0004] Secondly, it is highly irritating to the injection site. Current cimetidine injections frequently cause adverse reactions such as injection site pain and phlebitis during clinical use. Allergic reactions also occur occasionally, including allergic reactions, anaphylactic-like reactions, and even anaphylactic shock. Studies have shown that sulfite antioxidants are one of the important triggers for allergic reactions, and metal chelating agents may also irritate the injection site. These adverse reactions are clearly related to certain excipients in the formulation.

[0005] Third, the preparation process is complex and quality control is difficult. In existing technologies, the preparation of cimetidine injection often involves steps such as heating (e.g., 50-70℃) and activated carbon adsorption, which involves many process steps, increasing the risk of product contamination and batch-to-batch variability.

[0006] Fourth, there is insufficient attention paid to potential safety risks. Current technologies generally lack systematic research and quality control on genotoxic impurities, and the evaluation of factors affecting drug safety, such as packaging material compatibility, is inadequate. Cimetidine may generate potentially genotoxic impurities such as N-nitrosocimetidine during raw material synthesis, formulation production, and storage; existing quality standards largely fail to specifically control these impurities.

[0007] Therefore, developing a cimetidine injection with a simplified prescription, low irritation, simple manufacturing process, good stability, and comprehensive safety evaluation has significant clinical and industrial value. Summary of the Invention

[0008] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a cimetidine injection composition and its manufacturing process. The technical problem this invention aims to solve is: how to reduce the risk of allergic reactions and muscle irritation of the injection by removing antioxidants and metal chelating agents, thereby improving the safety of clinical medication.

[0009] The objective of this invention can be achieved through the following technical solutions: A cimetidine injection composition, said composition comprising the following components: Cimetidine; Hydrochloric acid solution is used to adjust the pH value; Sodium chloride is used to regulate osmotic pressure. Water for injection.

[0010] The composition contains no added antioxidants or metal complexing agents.

[0011] Preferably, the cimetidine injection composition contains 0.2g of cimetidine per 2ml.

[0012] Preferably, the pH value of the cimetidine injection composition is 5.0 to 6.8.

[0013] Preferably, the osmolar concentration of the cimetidine injection composition is 280–320 mOsmol / kg.

[0014] Preferably, the cimetidine injection composition is filled into ampoules or non-PVC multilayer co-extruded infusion bags, wherein the non-PVC multilayer co-extruded infusion bags are made of high-temperature resistant material.

[0015] A manufacturing process for a cimetidine injection composition includes the following steps: Step 1, Concentration: Add 60%–80% of the prescribed amount of water for injection to the concentration tank, and heat the solution to 40–60℃. 40–60℃ is the suitable temperature range for activated carbon for injection to adsorb pyrogens and impurities. Within this temperature range, cimetidine has stable solubility and no degradation, and the adsorption loss of the active pharmaceutical ingredient by activated carbon is extremely low, which can ensure the recovery rate of the active pharmaceutical ingredient while removing impurities. Add the prescribed amount of cimetidine, stir to dissolve, and adjust the pH value to 5.0–6.8 with hydrochloric acid solution. Nitrogen gas is introduced for protection during the concentration process to control the dissolved oxygen content in the solution to not exceed 2.0 mg / L. Step 2, activated carbon adsorption and decarbonization filtration: Add activated carbon for injection into the concentration tank, keep it at 40-60℃ and stir for adsorption, and after decarbonization filtration through a titanium rod filter, transfer the drug solution to the dilution tank. Step 3, dilution and volume adjustment: Add water for injection to the total volume, add sodium chloride to adjust the osmotic pressure to 280-320 mOsmol / kg, and stir evenly; nitrogen gas is continuously introduced for protection during the dilution process; Step 4, Circulation Filtration: The drug solution in the dilution tank is filtered through a circulation filtration system, passing sequentially through a 0.45μm polyethersulfone filter element and a 0.22μm polyethersulfone filter element for clarification / fine filtration. The filtration pressure is controlled at <0.2MPa, and the filtration flow rate is 10-15L / min. Nitrogen gas is introduced for protection throughout the circulation filtration process. Step 5, Intermediate product testing: The filtered drug solution is tested for intermediate products, including properties, pH value, color, content, osmolar concentration and microbial limit; Step 6, final sterilization filtration: The qualified drug solution is filtered for final sterilization through another independent 0.22μm polyethersulfone filter cartridge at a flow rate of 10-15L / min. Step 7, Filling and Sealing: In a cleanroom environment, fill the sterilized and filtered medication into ampoules or non-PVC multilayer co-extruded infusion bags, and seal them by melt sealing or heat sealing; before filling, purge the inside of the packaging container with nitrogen, and after filling, refill the headspace of the container with nitrogen to control the headspace residual oxygen rate to ≤5%; Step 8, Sterilization and Leak Detection: Place the filled and sealed product in a sterilization cabinet and sterilize at 121℃ for 15±5 minutes; after sterilization, use the color water method to detect leaks. Step 9, Light Inspection: Perform light inspection on products that have passed the leak test. The inspection items include appearance, color, seal, visible foreign matter, etc. Step 10, Outer Packaging: Products that pass the light inspection undergo outer packaging operations such as labeling, boxing, and packing.

[0016] Preferably, the hydrochloric acid solution in step one is a dilute hydrochloric acid solution with a concentration of 0.1 to 1.0 mol / L.

[0017] Preferably, in step two, the amount of activated carbon for injection is 0.01% to 0.05% of the volume of the drug solution, and the adsorption time is 10 to 20 minutes.

[0018] Preferably, the concentration of the sodium chloride solution in step three is 0.9%.

[0019] Preferably, in step four, the flow rate of the circulating filter is 10-15 L / min, the 0.45 μm polyethersulfone filter element is 10 inches, and the 0.22 μm polyethersulfone filter element is 5 inches.

[0020] Preferably, the F0 value of sterilization in step eight is not less than 8.

[0021] Preferably, in step eight, the colored solution used for leak detection is a 0.1 g / L methylene blue solution, the negative pressure vacuum is -80 kPa ± 20 kPa, the negative pressure leak detection time is 10 minutes, the positive pressure leak detection is +100 ± 20 kPa, and the positive pressure leak detection time is 10 minutes.

[0022] This invention also provides a quality control method for cimetidine injection, including the following testing items: (1) Determination of related substances: High performance liquid chromatography was used for determination, with octadecylsilane bonded silica gel as the packing material and phosphate buffer-methanol as the mobile phase. The detection wavelength was 220 nm. An impurity profile was established to identify the source, structure and removal pathway of the main impurities. (2) Determination of genotoxic impurities: The content of N-nitrosocimetidine was determined by liquid chromatography-tandem mass spectrometry, with a detection limit of not more than 0.05 ng / ml and a quantitation limit of not more than 0.15 ng / ml; (3) Content determination: The content was determined by high performance liquid chromatography; (4) Other items: pH value, color, osmolar concentration, visible foreign matter, insoluble particles, bacterial endotoxins, sterility, etc.

[0023] Compared with existing technologies, the cimetidine injection composition and its manufacturing process have the following advantages: This invention achieves a synergistic innovation through formulation simplification and process optimization. The composition contains only four components: cimetidine, hydrochloric acid solution, sodium chloride, and water for injection. It eliminates traditional antioxidants and metal chelating agents, reducing the risk of allergies and irritation from the source. Simultaneously, nitrogen purging throughout the process replaces chemical antioxidants, ensuring product stability. The process parameters are clearly defined and easy to operate, with strict control over genotoxic impurities. Non-clinical safety evaluations show superior muscle irritation compared to commercially available formulations, negative results for allergic and hemolytic reactions, and a cytotoxicity grade of 0-1. Furthermore, the packaging is flexible, achieving a balance between safety, stability, and clinical applicability. Attached Figure Description

[0024] Figure 1 This is a flowchart of the production process of cimetidine injection of the present invention.

[0025] Figure 2 This is the prescription form of Example 1 in this invention.

[0026] Figure 3 This is the prescription form of Example 2 in this invention.

[0027] Figure 4 This is the product quality standard table for the methodological verification of genotoxic impurities in this invention.

[0028] Figure 5 This is a table showing the gross anatomical findings of the rabbit muscle stimulation test in this invention.

[0029] Figure 6 This is a histopathological examination table of the rabbit muscle stimulation test in this invention.

[0030] Figure 7 This is an analysis table of the drug formulations used in the passive cutaneous anaphylaxis test of guinea pigs in this invention.

[0031] Figure 8 This is the analysis table of the drug formulations used in the guinea pig active systemic anaphylaxis test 1 of this invention.

[0032] Figure 9 This is the analysis table of the drug formulations used in the guinea pig active systemic anaphylaxis test 2 of this invention.

[0033] Figure 10 This is a summary table of non-clinical safety tests for cytotoxicity in this invention. Detailed Implementation

[0034] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings to further illustrate the technical solutions of the present invention. However, the present invention is not limited to these embodiments.

[0035] Example 1 (Ampoule Packaging) Prescription (for 1000 vials, 2 ml per vial), see the prescription table for Example 1. Figure 2 .

[0036] For the preparation process, see Figure 1 : Step 1, Concentration: Add about 1200ml of water for injection to the concentration vessel, heat to 40-60℃, add 200g of cimetidine, stir to dissolve, purge with nitrogen for protection, control the dissolved oxygen content in the solution to not exceed 2.0mg / L, and adjust the pH to 5.0-6.8 with 0.5mol / L hydrochloric acid solution. Step 2, activated carbon adsorption and decarbonization filtration: Add approximately 0.4g of activated carbon for injection (i.e., 0.02% g / ml) to the concentration tank, keep it at 40-60℃ and stir for 15 minutes for adsorption. After decarbonization filtration through a titanium rod filter, transfer the drug solution to the dilution tank. Step 3, dilution and volume adjustment: Add water for injection to 2000 ml, add sodium chloride to adjust the osmotic pressure to 280-320 mOsmol / kg, stir evenly, and continuously purge nitrogen gas for protection during the dilution process; Step 4, Circulation Filtration: The drug solution in the dilution tank is filtered through a circulation filtration system, passing sequentially through a 10-inch 0.45μm polyethersulfone filter and a 5-inch 0.22μm polyethersulfone filter for clarification filtration. The filtration pressure is <0.2MPa, the flow rate is 10-15L / min, and nitrogen gas is introduced for protection throughout the process. Step 5, Intermediate product testing: The filtered drug solution is tested for intermediate product properties, pH value, color, content, osmolar concentration, and microbial limits. Step 6, final sterilization filtration: The qualified drug solution is sterilized and filtered through redundant 0.22μm polyethersulfone filter cartridges at a flow rate of 10-15L / min; Step 7, Filling and Sealing: In a clean environment, fill the sterilized and filtered medicine solution into 2ml ampoules. Before filling, purge the inside of the ampoule with nitrogen. After filling, refill the headspace of the ampoule with nitrogen to control the headspace residual oxygen rate to ≤5%, and seal immediately. Step 8, Sterilization and Leak Detection: Place the filled product in a sterilization cabinet and sterilize at 121°C for 15 minutes; after sterilization, perform a leak test using the color water method. Step 9, Light Inspection: Perform light inspection on products that have passed the leak test: check for appearance, color, seal, visible foreign matter, etc. Step 10, Outer Packaging: Products that pass the light inspection undergo outer packaging operations such as labeling, boxing, and packing.

[0037] In step one, the hydrochloric acid solution is a dilute hydrochloric acid solution with a concentration of 0.1–1.0 mol / L.

[0038] In step two, the amount of activated carbon added for injection is 0.01% to 0.05% of the volume of the drug solution, and the adsorption time is 10 to 20 minutes.

[0039] In step three, the concentration of the sodium chloride solution is 0.9%.

[0040] In step four, the flow rate for circulating filtration is 10–15 L / min, the 0.45 μm polyethersulfone filter element is 10 inches, and the 0.22 μm polyethersulfone filter element is 5 inches.

[0041] The F0 value for sterilization in step eight shall not be less than 8.

[0042] In step eight, the color solution used for leak detection by the color solution method is a 0.1 g / L methylene blue solution. The negative pressure for leak detection is -80 ± 20 kPa, and the negative pressure leak detection time is 10 minutes. The positive pressure for leak detection is +100 ± 20 kPa, and the positive pressure leak detection time is 10 minutes.

[0043] Example 2 (ready-to-use infusion bag packaging) Prescription (based on 100 sachets, 100ml per sachet), see the prescription table in Example 2. Figure 3 .

[0044] Preparation process: Same as in Example 1, except that it is filled into a non-PVC multilayer co-extruded infusion bag and heat-sealed.

[0045] Example 3 (Different hydrochloric acid concentrations) The prescription is the same as in Example 1.

[0046] Preparation process: Same as in Example 1, except that in step one, 0.1 mol / L hydrochloric acid solution is used to adjust the pH.

[0047] Example 4 (Different hydrochloric acid concentrations) The prescription is the same as in Example 1.

[0048] Preparation process: Same as in Example 1, except that in step one, 1.0 mol / L hydrochloric acid solution is used to adjust the pH.

[0049] Pharmaceutical research I. Prescription Screening Research 1. Basis for the removal of antioxidants and metal complexing agents Those skilled in the art generally believe that antioxidants need to be added to injection solutions to prevent the oxidative degradation of the active pharmaceutical ingredient, and metal chelating agents need to be added to chelate any trace metal ions that may be introduced (to prevent their catalytic oxidation reaction). However, experimental studies have confirmed that: (1): Cimetidine has excellent chemical stability in a weakly acidic system with pH 5.0 to 6.8. When no antioxidants or metal complexing agents are added to the formulation, the relevant material indicators meet the legal quality standards as verified by accelerated stability test and long-term stability test. (2) Antioxidants (such as sodium sulfite, sodium metabisulfite, etc.) and metal complexing agents may cause irritation and allergic reactions at the injection site. Removing these excipients reduces the irritation of the formulation. (3) By optimizing the production process (such as full nitrogen protection and strict control of the filtration system), the stability of the product can be effectively guaranteed without relying on antioxidants and metal complexing agents.

[0050] Based on the above findings, the inventors determined a formulation for removing antioxidants and metal complexing agents.

[0051] 2. pH screening The effects of different pH values ​​(5.5, 6.0, 6.5, 7.0, 7.5) on the solubility and stability of cimetidine were investigated. The results showed that cimetidine exhibited good solubility within the pH range of 6.0–6.8, with the slowest growth of related substances. Therefore, the pH range of 6.0–6.8 was determined to be optimal.

[0052] 3. Screening of osmotic pressure regulators Commonly used osmotic pressure regulators such as sodium chloride and glucose were considered. Taking all factors into account, sodium chloride is the most commonly used isotonic regulator and does not interact with cimetidine. Therefore, sodium chloride was chosen to adjust the osmotic pressure to 280–320 mOsmol / kg.

[0053] II. Production Process Research 1. Research on concentrated preparation process (1) Study on the amount of water used for concentration: The effect of the amount of water for injection (60%, 70%, and 80% of the prescription amount) on the dissolution rate of cimetidine was investigated. The results showed that the highest efficiency was achieved when 70% of the prescription amount of water for injection was used for concentration and stirred for 15 to 20 minutes.

[0054] (2) Concentration temperature study: The effects of different temperatures (30℃, 40℃, 50℃, 60℃, 70℃) on the dissolution rate and stability of cimetidine were investigated. The results showed that the dissolution rate of cimetidine was significantly accelerated in the range of 40-60℃, and no new degradation products were detected, which was determined to be the preferred temperature range.

[0055] (3) Nitrogen purging protection study: The effect of nitrogen purging protection on the dissolved oxygen content in the drug solution was investigated. The results showed that the introduction of nitrogen gas during the concentrated preparation, dilute preparation, circulating filtration and filling process can control the dissolved oxygen content in the drug solution to below 2.0 mg / L, effectively preventing the oxidative degradation of the active pharmaceutical ingredient (cimetidine has a stable chemical structure in a weakly acidic system of pH 6.0 to 6.8 and an extremely low rate of oxidative degradation; nitrogen protection throughout the process can effectively reduce the dissolved oxygen and headspace residual oxygen in the drug solution, block the oxidation reaction pathway, and achieve formulation stability without excipients).

[0056] 2. Research on activated carbon adsorption process The effects of activated carbon dosage (0.01%, 0.02%, 0.05%, 0.08% g / ml) and adsorption time (10 min, 15 min, 20 min, 30 min) on pyrogen adsorption efficiency and drug adsorption loss were investigated. The results showed that activated carbon dosage of 0.01%–0.05% and adsorption time of 10–20 min could ensure pyrogen adsorption efficiency while controlling drug adsorption loss to within 0.5%. The optimal activated carbon dosage was determined to be 0.02% (g / ml) and the optimal adsorption time to be 15 min.

[0057] 3. Filtration Process Research The adsorption of cimetidine by filter cartridges of different materials (polyethersulfone, nylon, and polyvinylidene fluoride) was investigated. The results showed that the polyethersulfone filter cartridge exhibited virtually no adsorption of cimetidine, with a yield >99%, thus it was determined to be the preferred filter cartridge material. The filtration pressure was controlled at <0.2 MPa, and the flow rate at 10–15 L / min.

[0058] 4. Sterilization process research The effects of different sterilization conditions (115℃×30min, 121℃×15min, 121℃×20min) on product quality were investigated. The results showed that sterilization at 121℃×15min could guarantee the sterility assurance level (SAL≤10). -6 This method can minimize the generation of related substances and is therefore considered the optimal sterilization condition.

[0059] III. Quality Research 1. Validation of the methodology for related material research High-performance liquid chromatography (HPLC) was used to determine related substances. Chromatographic conditions: octadecylsilane-bonded silica gel as the stationary phase; phosphate buffer (pH 7.0)-methanol (80:20) as the mobile phase; detection wavelength 220 nm; flow rate 1.0 mL / min. Method validation results showed that the method had good specificity, and its precision, accuracy, linearity, and robustness all met the requirements. Based on this, a systematic impurity profile was established, clarifying the sources, structures, and removal pathways of the main impurities.

[0060] 2. Methodological validation for genotoxic impurity research The content of N-nitrosocimetidine was determined by liquid chromatography-tandem mass spectrometry (LC-MS / MS). After systematic optimization of the chromatographic-mass spectrometry conditions, method validation results showed that the limit of detection was 0.03 ng / mL, the limit of quantitation was 0.10 ng / mL, and the linearity was good in the range of 0.10–10 ng / mL (r>0.995), with recoveries of 95%–105%. N-nitrosocimetidine was not detected in any of the three batches of samples (below the limit of detection).

[0061] 3. Validation of content determination method The content was determined by high-performance liquid chromatography (HPLC). The chromatographic conditions were the same as those for the determination of related substances. Method validation results showed that the method has good specificity, and its precision, accuracy, linearity, and robustness all meet the requirements.

[0062] 4. Packaging material compatibility study A systematic compatibility study was conducted on the selected ampoules and non-PVC multilayer co-extruded infusion bags. Migration and adsorption tests were performed to investigate the effects of extractables and leachables in the packaging materials on product quality, as well as the adsorption of the active pharmaceutical ingredient by the packaging materials. The results showed that the selected packaging materials have good compatibility with the product and pose no safety risks.

[0063] 5. Product quality standards, and a table of product quality standards for methodological validation of genotoxic impurities research, see [link to table]. Figure 4 .

[0064] 6. Batch inspection report The batch inspection results of the three batches of samples submitted for registration all met the above-mentioned quality standards.

[0065] IV. Stability Study 1. Accelerated stability study (6 months) Three batches of samples were placed at a temperature of 40℃±2℃ and a relative humidity of 75%±5% for 6 months, and samples were taken for testing at 0, 1, 2, 3, and 6 months. The results showed that all indicators (including appearance, pH value, content, related substances, N-nitrosocimetidine, etc.) of the three batches of samples met the quality standard requirements within the 6-month accelerated test.

[0066] 2. Long-term stability study Three batches of samples were placed at a temperature of 25℃±2℃ and a relative humidity of 60%±10%, and samples were taken for testing at 0, 3, 6, 9, 12, 18, and 24 months. Long-term stability testing is underway, and the 12-month data shows that all indicators meet the quality standard requirements.

[0067] 3. Influencing Factors Experiment (1) High temperature test: The sample was placed at 60℃ for 10 days, and samples were taken for testing on the 5th and 10th days. The results showed that the related substances increased slightly under high temperature conditions, but still met the quality standard requirements.

[0068] (2) Strong light test: The samples were placed under an illuminance of 4500±500Lx for 10 days, and samples were taken for testing on the 5th and 10th days. The results showed that all indicators met the quality standard requirements under strong light conditions.

[0069] (3) High humidity test: The samples were placed under a relative humidity of 92.5% for 10 days (ampoules were sealed), and samples were taken for testing on the 5th and 10th days. The results showed that all indicators met the quality standard requirements under high humidity conditions.

[0070] Non-clinical safety trials This invention has completed a full non-clinical safety evaluation, and all tests were conducted in a GLP-certified laboratory. The testing was commissioned to Qingdao Kechuang Quality Testing Co., Ltd., with the specific testing work undertaken by Xi'an Guorui Yinuo Drug Safety Evaluation Research Co., Ltd., in accordance with the "Good Laboratory Practice for Non-Clinical Drug Studies" (implemented on September 1, 2017). The specific methods and results of each test are as follows.

[0071] I. Stimulation Test 1. Muscle stimulation test in rabbits Objective: To investigate whether local irritation reactions such as hyperemia, swelling, degeneration, and necrosis occurred at the injection site after intramuscular injection of the test product cimetidine in rabbits, and to compare it with commercially available formulations, so as to provide a reference for safe clinical drug use.

[0072] Methods: Twelve New Zealand rabbits that had passed quarantine and adaptation were randomly divided into two groups of six each (half male and half female) based on body weight. One group was the test product group, and the other was the commercially available control group. A self-comparison method was used, with the left side receiving either the test product or the commercially available control product, cimetidine injection (100 mg / mL, the maximum clinical concentration), and the right side receiving the negative control product, 0.9% sodium chloride injection. The dosage for all three products was 1 mL per side, administered once daily for seven consecutive days. Seventy-two hours after the last administration (D10), three animals from each group were sacrificed. The remaining animals were allowed 14 days to recover before being sacrificed (D24). Muscle tissue from the injection site (including the needle mark and approximately 1 cm surrounding it) was collected for histopathological examination. The muscle irritation of the test product was determined based on a combination of visual observation and histopathological examination results.

[0073] result: (1) General symptom observation: During the experiment, no abnormalities were observed in the general symptoms of the rabbits in the test group and the commercially available control group, including mental state, behavior, secretions, respiration, and fecal characteristics.

[0074] (2) Macroscopic observation of the administration site: Before each administration, 24h, 48h, 72h after the last administration, and at the end of the recovery period, no irritating reactions such as redness, swelling, ecchymosis, ulceration, or induration were observed at the administration site in rabbits of all groups.

[0075] (3) Gross anatomical findings (72 hours after the last administration), see the table of gross anatomical findings. Figure 5 .

[0076] Test sample group: Total reaction grade score 2 points, average score 0.67, reaction grade is mild irritation.

[0077] Commercially available control group: Total response score of 5 points, average score of 1.67, response level of mild stimulation.

[0078] (4) Gross anatomical findings during the recovery period (D24): Test sample group: punctate hemorrhages were observed in the left quadriceps muscle of rabbit No. 2117 (reaction grade 1), while no abnormalities were observed in the other rabbits. The total reaction grade score was 1 point, with an average score of 0.33, indicating a reaction level of no irritation.

[0079] Commercially available control group: No abnormalities were observed in the quadriceps muscles on both sides of all rabbits.

[0080] (5) Histopathological examination: Histopathological examination 72 hours after the last administration, see the table below. Figure 6 .

[0081] Recovery period ended (D24): In the test group, edema, fibrosis, necrosis, and inflammatory cell infiltration of skeletal muscle tissue were still visible on the left side of two rabbits; the same lesions were also visible on the left side of one rabbit in the commercially available control group. This suggests that the muscle tissue at the drug administration site showed signs of incomplete repair during the recovery period.

[0082] Conclusion: Under the conditions of this experiment, when the test product cimetidine injection was administered intramuscularly to rabbits at a clinically administered concentration of 100 mg / mL and a dosage volume of 1 mL / rabbit, once daily for 7 consecutive days, it had a certain muscle irritation effect (mild irritation) on the rabbits. The necrotic parts were irreversible, but the irritation was lower than that of the commercially available control product (mild irritation).

[0083] 2. Intravenous injection vascular irritation test in rabbits Objective: To observe whether local vascular dilation, congestion, endothelial cell degeneration and necrosis, and surrounding tissue edema and inflammatory cell infiltration occur after bolus injection of the test product cimetidine into the ear vein of rabbits, and to compare with commercially available formulations.

[0084] Methods: Twelve New Zealand rabbits that had passed quarantine and adaptation were randomly divided into two groups based on body weight: a test group and a commercially available control group, with six rabbits in each group (half male and half female). A self-comparison method was used, with the left ear receiving either the test product or the commercially available control, cimetidine injection (concentration 10 mg / mL, volume 5 mL / kg, dose 50 mg / kg), and the right ear receiving a negative control, 0.9% sodium chloride injection. The administration rate was 300 mL / h. Administered once daily for seven consecutive days. Seventy-two hours after the last administration (D10), three rabbits from each group were dissected, and the remaining rabbits were observed for 14 days (D24) for histopathological examination.

[0085] result: (1) Concentration analysis of the drug-coated formulation: The accuracy of the first and last tests for the test solution was 96.94% and 96.71%, respectively, with RSDs of 1.24% and 1.75%, respectively; the accuracy of the first and last tests for the commercially available reference solution was 98.81% and 98.38%, respectively, with RSDs of 1.87% and 1.19%, respectively. All results met the acceptance criteria.

[0086] (2) General symptom observation: During the experiment, no abnormalities were observed in the general symptoms of rabbits in all groups.

[0087] (3) Macroscopic observation of the administration site: Before each administration, 24h, 48h, 72h after the last administration, and at the end of the recovery period, no local irritation reactions such as vascular congestion and surrounding tissue edema were observed in the left and right ears of all groups of rabbits. The scores were all 0, and it was judged that there was no obvious reaction.

[0088] (4) Gross anatomical findings: 72 hours after the last administration and at the end of the recovery period, no abnormalities were found in the blood vessels and surrounding tissues of the left and right ears of rabbits in all groups.

[0089] (5) Histopathological findings: 72 hours after the last administration and at the end of the recovery period, no abnormal pathological changes were observed in the blood vessels and surrounding tissues of the left and right ears of all rabbits in the test group and the commercially available control group under a microscope.

[0090] Conclusion: Under the experimental conditions, when the test product was administered at the designed dose once daily for 7 consecutive days, no irritant effect of the test product cimetidine injection on the blood vessels of New Zealand rabbits was found.

[0091] II. Allergy Test 1. Passive cutaneous anaphylaxis (PCA) test in guinea pigs (1) Experiment 1 (high concentration: 100 mg / mL and 50 mg / mL) Objective: To investigate whether cimetidine injection induces passive cutaneous anaphylaxis in guinea pigs and the degree of the reaction.

[0092] Methods: Sixty qualified guinea pigs (half male and half female) were selected for quarantine adaptation. Twenty-four were used for antiserum preparation, and 36 were used for passive skin sensitization and challenge. Guinea pigs were divided into a negative control group (0.9% sodium chloride injection), a low-dose test sample group (25 mg / guinea pig), a high-dose test sample group (50 mg / guinea pig), a low-dose commercially available control sample group (25 mg / guinea pig), a high-dose commercially available control sample group (50 mg / guinea pig), and a positive control group (ovalbumin 5 mg / guinea pig). For antiserum preparation, guinea pigs were sensitized by intraperitoneal injection of 0.5 mL / guinea pig every other day for a total of three times. Blood was collected from the heart on day 14 after the last sensitization, and serum was separated. The serum was serially diluted with 0.9% sodium chloride injection (1:2, 1:8, 1:16, 1:32). Twenty-four hours after passive sensitization, 0.5 mL of each drug solution and 0.5 mL of 1% Evans blue solution were injected intravenously for challenge. The diameter of the blue spot in the inner layer of the skin was measured 30 minutes later; a value greater than 5 mm was considered positive.

[0093] result: Analysis of drug-eluting formulations: The accuracy of the low-dose group of the test sample was 102.15% (RSD 1.29%), the accuracy of the high-dose group of the test sample was 103.62% (RSD 0.58%), the accuracy of the low-dose group of the commercially available reference product was 103.35% (RSD 0.55%), and the accuracy of the high-dose group of the commercially available reference product was 104.45% (RSD 1.28%). All met the acceptance criteria. See the table below for drug-eluting formulations. Figure 7 .

[0094] Conclusion: Cimetidine injection did not induce passive cutaneous anaphylaxis in guinea pigs at concentrations of 50 mg / mL and 100 mg / mL, and the reaction was negative.

[0095] (2) Experiment 2 (low concentrations: 10 mg / mL and 5 mg / mL) Objective: To investigate whether cimetidine injection at clinically used concentrations induces passive cutaneous anaphylaxis in guinea pigs.

[0096] Methods: Same as Experiment 1, except that the drug concentration was adjusted to 5 mg / mL for the low-dose group and 10 mg / mL for the high-dose group of the test substance / commercial control substance, and 10 mg / mL for the positive control group of ovalbumin.

[0097] result: Analysis of the drug formulations: The mean measured concentration of the test sample in the low-dose group was 101.81% (RSD 0.93%), the mean measured concentration in the high-dose group was 101.46% (RSD 1.79%), the mean measured concentration in the low-dose group of the commercially available reference product was 103.02% (RSD 0.77%), and the mean measured concentration in the high-dose group of the commercially available reference product was 105.02% (RSD 1.22%), all of which met the acceptance criteria.

[0098] No blue spots appeared in any of the six guinea pigs in the negative control group; in the positive control group, blue spots larger than 5 mm in diameter (13–40 mm in diameter) appeared at all four dilutions of antiserum injection sites in all six guinea pigs, confirming the validity of the test system. No blue spots appeared at any of the four dilutions of antiserum injection sites in the high- and low-dose groups of the test sample and the commercially available control, indicating a negative allergic reaction.

[0099] Conclusion: Cimetidine injection did not induce passive cutaneous anaphylaxis in guinea pigs at concentrations of 5 mg / mL and 10 mg / mL, and the reaction was negative.

[0100] 2. Guinea pig active systemic anaphylaxis test (1) Experiment 1 (high concentration: 100 mg / mL and 50 mg / mL) Objective: To investigate whether cimetidine injection can induce active systemic allergic reactions and the intensity of allergic reactions.

[0101] Methods: Forty-eight quarantine-adapted guinea pigs were randomly divided into four groups: a negative control group (0.9% sodium chloride injection), a low-dose test sample group (50 mg / mL), a high-dose test sample group (100 mg / mL), a low-dose commercially available control sample group (50 mg / mL), a high-dose commercially available control sample group (100 mg / mL), and a positive control group (ovalbumin 10 mg / mL), with eight animals in each group. Sensitization was achieved by intraperitoneal injection of 0.5 mL / animal every other day for a total of three times. On day 14 (D19) and day 21 (D26) after the last sensitization, four animals from each group were challenged by intravenous injection of 1.0 mL / animal. Allergic reaction symptoms were observed within 30 minutes after challenge.

[0102] result: Analysis of the drug formulations: For the first sensitization, the accuracy was 95.09% (RSD 1.91%) for the low-dose group and 95.15% (RSD 2.24%) for the high-dose group; for the final challenge, the accuracy was 100.76% (RSD 1.38%) for the low-dose group and 99.48% (RSD 1.21%) for the high-dose group. Both met the acceptance criteria. The drug formulation analysis table for Experiment 1 is available in [link to table]. Figure 8 .

[0103] Discussion: Eight healthy, non-sensitized guinea pigs were divided into two groups and intravenously injected with low / high dose solutions of the test product and low / high dose solutions of the commercially available control product, respectively. All animals exhibited symptoms similar to allergic reactions (convulsions, rapid breathing, urination, death, etc.). This suggests that at concentrations of 100 mg / mL and 50 mg / mL, the test product and the commercially available control product may cause non-immune-mediated allergic-like reactions (such as direct stimulation of mast cells to release histamine) due to excessively high drug concentrations or excipient factors. This reaction is concentration-dependent and differs from the mechanism of type I allergic reactions mediated by immunoglobulin E (IgE).

[0104] Conclusion: Cimetidine injection, at concentrations of 100 mg / mL and 50 mg / mL, produced allergic reactions similar to those caused by the test product.

[0105] (2) Experiment 2 (low concentrations: 10 mg / mL and 5 mg / mL) Objective: To investigate whether cimetidine injection at clinically used concentrations can induce active systemic allergic reactions.

[0106] Methods: Same as Experiment 1, except the drug concentration was adjusted to 5 mg / mL for the low-dose group and 10 mg / mL for the high-dose group of the test substance / commercially available control.

[0107] result: No allergic reactions were observed in the negative control group; the incidence of allergic reactions in the positive control group was 100%, which was rated as extremely positive, thus the test system was valid. The analysis table of the drug formulations used in Test 2 is available in [link to table]. Figure 9 .

[0108] Conclusion: Cimetidine injection did not induce active systemic allergic reactions in guinea pigs at concentrations of 5 mg / mL and 10 mg / mL, and the reactions were negative.

[0109] III. Hemolytic Test 1. Experiment 1 (High concentration: 100 mg / mL) Objective: To investigate whether cimetidine injection causes hemolysis and erythrocyte aggregation in rabbit erythrocytes.

[0110] Methods: Take 12 clean test tubes. Tubes 1-5 are the test sample tubes, tube 6 is the negative control tube, tube 7 is the positive control tube, and tubes 8-12 are commercially available control tubes. Add 2% (mL / mL) red blood cell suspension, 0.9% sodium chloride injection, purified water, and the test sample or commercially available control (concentration 100 mg / mL) sequentially. Shake well and incubate at 37.0–37.1℃. Observe hemolysis at 15 min, 30 min, 45 min, 1 h, 2 h, and 3 h. Centrifuge at 2500 r / min for 5 min after 3 h and observe.

[0111] Results: No hemolysis or erythrocyte aggregation was observed in the negative control tubes; complete hemolysis was observed in the positive control tubes, indicating the validity of the test system. No hemolysis or erythrocyte aggregation was observed in test tubes 3-5 and commercially available control tubes 10-12; partial hemolysis was observed in test tubes 1-2 and commercially available control tubes 8-9.

[0112] Conclusion: Cimetidine injection, at a concentration of 100 mg / mL, had a partial hemolytic effect on rabbit erythrocyte suspension, and the results were consistent with those of the commercially available reference product.

[0113] 2. Experiment 2 (low concentration: 10 mg / mL) Objective: To investigate whether cimetidine injection at clinically used concentrations causes hemolysis and erythrocyte aggregation in rabbit erythrocytes.

[0114] Method: Same as Experiment 1, except the concentrations of the test sample and the commercially available reference sample were adjusted to 10 mg / mL.

[0115] result: Analysis of the drug formulation: The accuracy of the test solution was 105.28% (RSD 0.51%), and the accuracy of the commercially available reference solution was 107.32% (RSD 0.45%), both of which met the acceptance criteria.

[0116] Observations were made within 3 hours after sample addition and after centrifugation: No hemolysis was observed in negative control tube No. 6; complete hemolysis was observed in positive control tube No. 7, indicating the validity of the test system. No hemolysis or erythrocyte aggregation was observed in test tubes No. 1-5 and commercially available control tubes No. 8-12 within 3 hours after sample addition.

[0117] Conclusion: Cimetidine injection at a concentration of 10 mg / mL did not cause hemolysis or erythrocyte aggregation in rabbit erythrocyte suspension.

[0118] IV. Cytotoxicity Test Mouse fibroblast L929 cells were used for cytotoxicity assays using the MTT assay. Sample groups (Example 1 of this invention), negative control groups, and positive control groups were set up. Relative cell proliferation rate (RGR) was measured to evaluate cytotoxicity grading.

[0119] Results: The relative cell proliferation rate of the sample group of the present invention was >80%, and the cytotoxicity grade was 0 or 1 (no toxicity or slight toxicity), indicating that the sample of the present invention had low cytotoxicity, which further confirms its good biosafety.

[0120] Summary table of non-clinical safety trials, see Figure 10 .

[0121] In summary, the composition of this invention contains only four components: cimetidine, hydrochloric acid solution, sodium chloride, and water for injection, completely eliminating antioxidants (such as sulfites) and metal chelating agents (such as EDTA-2Na) commonly used in traditional formulations. This simplified approach effectively avoids allergic reactions and injection site irritation induced by excipients such as sulfites, reducing the risk of adverse clinical reactions from the source and improving medication safety.

[0122] This invention ensures stability through system optimization in the production process. Nitrogen gas is introduced throughout the entire process of concentrated preparation, dilution, circulating filtration, and filling to strictly control dissolved oxygen (≤2.0 mg / L) and headspace residual oxygen (≤5%). This technology effectively replaces the addition of traditional antioxidants, simplifying the formulation while ensuring that all indicators of the product meet the requirements in accelerated and long-term stability tests.

[0123] The present invention features a compact process, with the concentration temperature controlled between 40 and 60°C. This facilitates the adsorption of pyrogens and impurities by activated carbon while ensuring the solubility and stability of the active pharmaceutical ingredient. The parameters for each step are clearly defined (e.g., filtration pressure <0.2 MPa, flow rate 10–15 L / min). Combined with a titanium rod filtration decarbonization and redundant sterilization filtration system, the operation is simple, quality control is precise, and the risk of contamination and batch-to-batch variability are effectively reduced.

[0124] The product of this invention has a stable pH value of 5.0–6.8 and an osmolality controlled between 280–320 mOsmol / kg. A systematic impurity profile was established in the quality study, clarifying the sources, structures, and removal pathways of the main impurities. Batch testing results of the three registered batches of samples all met the high-standard quality requirements, demonstrating good product homogeneity and reproducibility.

[0125] This invention establishes a highly sensitive LC-MS / MS detection method (detection limit 0.03 ng / ml) for the potential genotoxic impurity N-nitrosocimetidine, and completes a systematic non-clinical safety evaluation. The impurity was not detected in any of the three batches of samples, fully demonstrating the invention's comprehensive control over drug safety risks.

[0126] A complete non-clinical safety evaluation showed that the rabbit muscle irritation of this invention was mild (superior to the mild irritation of commercially available formulations); vascular irritation, allergic reactions (PCA and active anaphylaxis), and hemolysis tests (clinical concentrations) were all negative; cytotoxicity was grade 0 or 1. All results were consistent with or better than commercially available control products, providing strong assurance for safe clinical use.

[0127] Accelerated testing (40℃±2℃, 6 months) and long-term testing (25℃±2℃, 12 months) showed that the product of this invention remained stable in key indicators such as appearance, pH value, content, and related substances. Influencing factor tests (high temperature, strong light, high humidity) also showed that the product has good tolerance, ensuring the product's quality stability throughout its shelf life.

[0128] The composition of this invention can be filled into ampoules or into non-PVC multilayer co-extruded infusion bags. The ready-to-use infusion bag packaging avoids the risk of secondary contamination during clinical use, simplifies clinical procedures, improves the convenience and safety of medication administration, and can meet the needs of different clinical scenarios.

[0129] This invention achieves a balance between safety, stability, and economy by combining a simplified prescription with optimized processes—using a weakly acidic system (pH 5.0–6.8) to ensure the chemical stability of cimetidine, using nitrogen purging throughout the process to block oxidation pathways, using activated carbon to adsorb and remove pyrogens and impurities, and using a polyethersulfone filter to ensure a filtration yield (>99%).

[0130] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A cimetidine injection composition, characterized in that, The composition comprises the following components: cimetidine, hydrochloric acid solution, sodium chloride and water for injection; the pH value of the composition is 5.0 to 6.8; the osmolality of the composition is 280 to 320 mOsmol / kg; and the content of cimetidine is 0.2 g per 2 ml.

2. The cimetidine injection composition according to claim 1, characterized in that, The composition is filled into ampoules or non-PVC multilayer co-extruded infusion bags.

3. A manufacturing process for preparing the cimetidine injection composition as described in claim 1 or 2, characterized in that, Includes the following steps: Step 1, Concentration: Add water for injection to the concentration tank, control the temperature of the drug solution to 40-60℃, add cimetidine, stir to dissolve, adjust the pH value to 6.0-6.8 with hydrochloric acid solution, purge with nitrogen for protection, and control the dissolved oxygen content in the drug solution to not exceed 2.0mg / L; Step 2, activated carbon adsorption and decarbonization filtration: Add needle-grade activated carbon, keep warm and stir for adsorption, and then filter through a titanium rod filter for decarbonization filtration; Step 3, dilution and volume adjustment: Add water for injection to the total volume, add sodium chloride to adjust the osmotic pressure to 280-320 mOsmol / kg, and continuously purge with nitrogen for protection; Step 4, Circulation Filtration: The drug solution is filtered sequentially through a 0.45μm polyethersulfone filter and a 0.22μm polyethersulfone filter, with a filtration pressure of <0.2MPa and nitrogen gas purging throughout the process for protection. Step 5, Intermediate product testing: testing for appearance, pH value, color, content, osmolality, and microbial limits; Step 6, final sterilization filtration: The qualified drug solution is then subjected to final sterilization filtration through another independent 0.22μm polyethersulfone filter cartridge; Step 7, filling and sealing: Filling into ampoules or non-PVC multilayer co-extruded infusion bags in a clean area. Before filling, the inside of the packaging container is purged with nitrogen. After filling, the headspace is refilled with nitrogen to control the headspace residual oxygen rate to ≤5%. Then, it is fused or heat-sealed. Step 8, Sterilization and Leak Detection: Sterilize at 121℃ for 15±5 minutes; use colorimetric water method for leak detection; Step 9, Lamp Inspection: Perform lamp inspection on products that have passed the leak detection. Step 10, Outer Packaging: Products that pass the light inspection are labeled, boxed, and packed into cartons for outer packaging.

4. The production process of the cimetidine injection composition according to claim 3, characterized in that, In step two, the amount of activated carbon added is 0.01% to 0.05% of the drug solution volume, and the adsorption time is 10 to 20 minutes. In step three, the concentration of sodium chloride solution is 0.9%.

5. The manufacturing process of a cimetidine injection composition according to claim 4, characterized in that, In step four, the flow rate of the circulating filter is 10-15 L / min, the 0.45 μm polyethersulfone filter element is 10 inches, and the 0.22 μm polyethersulfone filter element is 5 inches.

6. The manufacturing process of a cimetidine injection composition according to claim 5, characterized in that, The F0 value for sterilization in step eight is not less than 8; the color solution used for leak detection in step eight is 0.1 g / L methylene blue solution, the negative pressure for leak detection is -100 kPa to -60 kPa, the negative pressure leak detection time is 10 minutes, the positive pressure for leak detection is +80 kPa to +120 kPa, and the positive pressure leak detection time is 10 minutes.

7. A quality control method for preparing the cimetidine injection composition as described in claim 1 or 2, characterized in that, The content of N-nitrosocimetidine was determined by liquid chromatography-tandem mass spectrometry. The limit of detection of this method was not higher than 0.05 ng / ml, and the limit of quantitation was not higher than 0.15 ng / ml.

8. The quality control method for preparing a cimetidine injection composition according to claim 7, characterized in that, High-performance liquid chromatography was also used to determine the relevant substances and their contents, establish an impurity profile, and clarify the source, structure, and removal pathway of the main impurities.

9. The use of the cimetidine injection composition according to claim 1 or 2 in the preparation of a drug for treating peptic ulcers.

10. The use of the cimetidine injection composition according to claim 1 or 2 in the preparation of a drug for preventing stress ulcers.

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