A sulfonamide and antibacterial synergist compound solution and its preparation method and application

Abstract

The present invention discloses a compound solution of a sulfonamide and an antimicrobial synergist, its preparation method, and application. The compound solution further comprises a solvent, a pH buffer system, and a diluent; the solvent is N-methylpyrrolidone, and the pH buffer system is triethanolamine and an organic acid. The present invention discloses a stable, clear compound solution of a sulfonamide and an antimicrobial synergist, and its preparation method. The compound solution can be mixed with water for administration, exhibits excellent stability and lacks a distinctive odor after mixing with water, and eliminates problems such as uneven mixing of existing premixes and low intake of sick animals when their appetite decreases.

Description

Technical Field

[0001] The invention belongs to the technical field of veterinary drug preparations, and particularly relates to a sulfonamide and antibacterial synergist compound solution, a preparation method and application thereof. Background Art

[0002] Sulfonamides are among the oldest antimicrobial compounds still in use today. Although microorganisms have developed widespread resistance to them when used alone, the advent of antimicrobial synergists such as trimethoprim has significantly extended the usefulness of sulfonamides. Chemically, these synergists belong to the diaminopyrimidine class and possess broad-spectrum antimicrobial activity. However, when used alone, they only produce an antimicrobial effect and are prone to developing resistance. Therefore, they are often used in combination with sulfonamides in a 1:5 ratio. Combining these drugs with sulfonamides not only produces synergistic effects but also delays the development of sulfonamide resistance in susceptible bacteria. Consequently, sulfonamides remain an important antimicrobial agent in livestock and poultry anti-infective therapy. Sulfadimethoxine, also known as sulfadimethoxine, is a low-dose, rapidly absorbed, and long-acting sulfonamide. Its antimicrobial spectrum is similar to that of sulfadiazine, but it exhibits stronger antimicrobial activity and potent anticoccidial activity. Furthermore, sulfadimethoxine is relatively soluble at normal kidney pH, eliminating the possibility of precipitation and crystallization. In addition, due to its slow renal clearance rate and high plasma protein binding rate, sulfadimethoxine can maintain a higher blood concentration level than most other long-acting sulfonamides, allowing a relatively low dosage to produce rapid and long-lasting therapeutic blood concentrations. To date, antimicrobial enhancers that have been used in medical and veterinary clinics include trimethoprim, dimethoprim, adiprim, and ormeprim, among which dimethoprim, adiprim, and ormeprim are antimicrobial enhancers specifically for veterinary use. Due to safety issues, dimethoprim is currently only used in veterinary clinics in my country and has been eliminated in developed countries such as the European Union; while another antimicrobial enhancer, trimethoprim, is widely used in my country and is a product for both humans and animals. The U.S. FDA has approved the sulfadimethoxine and ormeprim combination premix developed by Zoetis Inc. 40 tablets They are used for poultry such as chickens, turkeys and ducks, and dogs respectively. 40 It is used in broilers, breeders and laying hens to prevent coccidiosis caused by Eimeria tenella and other Eimeria coccidia, as well as infectious rhinitis, Escherichia coli disease and fowl cholera; in turkeys to prevent coccidiosis and fowl cholera caused by Eimeria adenoeides and other species; in quails to prevent coccidiosis caused by Eimeria kofoidi and other species; in addition, it can be used to control fowl cholera in breeder ducks, and in ducks to control bacterial infections caused by Escherichia coli, Riemerella anatipestifer and Pasteurella multocida. It has a preventive or control effect on various coccidiosis and bacterial diseases in poultry; at the same time, the compound premix of sulfadiazolidine and omeprazole developed by Pharmaq AS -30 is also approved for aquaculture. The compound product of sulfadiazolidine and omeprazole has broad application prospects in animal husbandry, pet diagnosis and treatment, and aquaculture. Although 12.5% ​​sulfadiazolidine solution In the United States, it has been approved for the treatment of parasitic and bacterial diseases in chickens, turkeys, dairy cows, and beef cattle. The route of administration is mixing with water. However, the combination products of sulfadiazolidine and sulfadiazolidine approved abroad are currently only tablets and premixes. Tablets are not suitable for group administration, and premixes need to be mixed with feed, which may lead to problems such as uneven mixing, poor appetite of sick animals, and low drug intake.

[0003] The "2020 Report on the Use of Veterinary Antimicrobial Drugs in China" shows that by category of veterinary antimicrobial drugs, the top three in terms of usage are tetracyclines (10,003 tons, accounting for 30.52%), sulfonamides and synergists (4,288 tons, accounting for 13.08%), and β-lactams and inhibitors (4,113 tons, accounting for 12.55%). my country's livestock breeding and other industries have a considerable demand for sulfonamides and synergists. In addition, among the veterinary antimicrobial drugs used in 2020, sulfonamides and synergists had the largest number of single-category antimicrobial drugs (11), and the number of sulfonamide and synergist preparations was also the largest (46). However, the ratio of APIs to preparations was only about 1:4, lower than the 1:5 to 1:7 ratio in Europe and the United States. my country is a major livestock and poultry producer. Veterinary antibiotics are primarily administered through feed (40%) and drinking water (34%). Premixes are used exclusively for feed, while soluble powders and solutions are available for drinking water. The "Guiding Opinions on Promoting the Healthy Development of the Veterinary Drug Industry," issued in 2016, set "further diversification of product offerings" as a primary goal. Furthermore, "adjusting product structure—supporting the development of animal-specific APIs and preparations" is one of the measures to optimize the current veterinary drug industry structure and enhance intensive development. The development of solutions of sulfadiazolidine and omeprazole has practical significance for increasing the diversity of my country's veterinary drug product portfolio. Furthermore, providing high-quality animal-specific antimicrobial drugs for my country's livestock and poultry sector has the potential to boost the healthy development of both the animal husbandry and veterinary drug industries.

[0004] There are three difficulties in preparing a compound solution of sulfadimethoxine and ollmeprim. The first is that both sulfadimethoxine and ollmeprim are insoluble in water and systems consisting of water and other solvents. A lot of screening is required to find a solvent that can dissolve both of them at the same time, and at the same time, select a suitable process to improve the solubility of both. The second is to make the weakly acidic drug sulfadimethoxine and the weakly alkaline drug ollmeprim co-dissolve and stably dissolve in the solution. The third is to combine the clinical application scenarios. After the solution is diluted with water, sulfadimethoxine and ollmeprim must be stably dissolved in water at a certain dilution multiple. Summary of the Invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a stable and clear compound solution of sulfonamide and antibacterial synergist, as well as its preparation method and application.

[0006] Technical solution: The sulfonamide-antibacterial synergist compound solution of the present invention further comprises a solvent, a pH buffer system and a diluent; the solvent is N-methylpyrrolidone, and the pH buffer system is triethanolamine and an organic acid.

[0007] Furthermore, the sulfa drug is sulfadiazolidine.

[0008] Furthermore, the antibacterial synergist includes one of trimethoprim, ditrimethoprim, adiprim, and ormeprim.

[0009] Furthermore, the organic acid is lactic acid or acetic acid.

[0010] Furthermore, the diluent includes N-methylpyrrolidone or dimethyl sulfoxide.

[0011] Furthermore, each 100 mL of the compound solution contains 12.5-25.0 g of sulfadiazolidine, 2.5-5.0 g of ormeprim, 10-30 mL of N-methylpyrrolidone, 2.2-41 g of triethanolamine, and 2.5-7.6 g of an organic acid, and the diluent is supplemented to 100 mL.

[0012] Specifically, each 100 mL of the solution contains 12.5 g of sulfadiazolidine, 2.5 g of ormeprim, 20 mL of N-methylpyrrolidone, 20-22 g of triethanolamine, 3.8 g of lactic acid or 2.5 g of acetic acid, and dimethyl sulfoxide or N-methylpyrrolidone to make up to 100 mL.

[0013] Furthermore, the mass ratio of sulfadiazolidine to ormeprim is 5:1 or 5:3.

[0014] The preparation method of the sulfonamide-antibacterial synergist compound solution of the present invention comprises the following steps: mixing sulfadiazol and ormeprim at room temperature, adding N-methylpyrrolidone to dissolve most of the drugs; adding triethanolamine, stirring / ultrasounding until the drugs are completely dissolved; adding lactic acid or acetic acid and mixing evenly; and adding N-methylpyrrolidone or dimethyl sulfoxide to adjust the volume to obtain the sulfonamide-antibacterial synergist compound solution.

[0015] The preparation method of the sulfonamide-antibacterial synergist compound solution of the present invention comprises the following steps: taking sulfadiazolidine and adding N-methyl pyrrolidone to dissolve the drug at room temperature; adding triethanolamine and stirring until the drug is completely dissolved; adding lactic acid or acetic acid and mixing evenly; adding ormeprim, stirring and then ultrasonicating until dissolved; and adding N-methyl pyrrolidone or dimethyl sulfoxide to adjust the volume to obtain the sulfonamide-antibacterial synergist compound solution.

[0016] The invention relates to an application of the sulfonamide-antibacterial synergist compound solution in preventing and / or treating Eimeria tenella infection in animals.

[0017] Beneficial Effects: Compared with existing technologies, the present invention has the following significant advantages: It discloses a stable, clear compound solution of a sulfa drug and an antibacterial synergist, and its preparation method. The compound solution of the present invention can be used for mixed drinking and administration. After mixing with water, it exhibits excellent stability and lacks a distinctive odor. The solution eliminates the problems of uneven mixing with existing premixes and reduced intake in sick animals due to decreased appetite, thereby enriching the dosage forms of the sulfadiazolidine and omeprazole compound. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 To investigate the stability of sulfadiazolidine and omepramine solutions at different concentrations;

[0019] Figure 2 This is an investigation of the buffer system when the ratio of sulfadiazolidine to ormeprim is 5:3. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0021] Example 1 Selection of auxiliary materials and process research

[0022] 1. Determination of auxiliary materials

[0023] In the early stages of the research, we searched related patents and products of similar pharmaceutical preparations, the FDA database of inactive ingredients, consulted professional books and literature, and combined them with the physical and chemical properties of the drugs to determine a series of basic excipient compositions. Based on the solubility and visual water stability results of different combinations, we screened out the excipient combinations listed in Table 1.

[0024] Table 1 Combination of prescription excipients and their functions

[0025]

[0026] Sulfadimethoxine has good solubility and stability in aqueous sodium hydroxide solution. The United States already has a 12.5% ​​sulfadimethoxine solution. Approved for use in animals, the excipients are sodium edetate, sodium bisulfite, sodium hydroxide and water. However, ormeprim is difficult to dissolve in inorganic alkaline solutions, so the main focus is on organic solvents when selecting solvents. In previous studies, ormeprim had a low proposed content per milliliter and had a certain solubility in lactic acid and dimethyl sulfoxide before salt formation. It was also soluble in propylene glycol and propylene glycol aqueous solution after salt formation with organic acids; but sulfadiazolidine had a high proposed content per milliliter and was only well soluble in N-methylpyrrolidone and 2-pyrrolidone after salt formation. 2-Pyrrolidone LD 50 It is higher than N-methylpyrrolidone, but it has not been registered as a pharmaceutical excipient in China. In addition, the stability of sulfadiazolidine and ormeprim in this solvent is affected by many factors and is very easy to precipitate.

[0027] Both sulfadimethoxine and ormeprim are poorly water-soluble drugs. Although sulfadimethoxine contains a weakly basic amine group, the presence of the sulfonyl group gives it a pKa of 6.3, making it a weak acid. Ormeprim, on the other hand, contains two amine groups, making it a weak base. Salting can improve the solubility of drugs that are insoluble or poorly soluble in solvents. Furthermore, salting drugs readily converts them to ionized forms in water, increasing their solubility. Sulfadimethoxine can form salts with triethanolamine, increasing its solubility in solvents. Ormeprim can also form salts with acids. Therefore, process research is primarily focused on salifying poorly soluble drugs.

[0028] Test 1): Omeprim is insoluble in N-methylpyrrolidone;

[0029] Test 2): Omeprim is insoluble in a solvent system consisting of N-methylpyrrolidone and triethanolamine;

[0030] Test 3): Omeprim and sulfadiazolidine were mixed and dissolved in N-methylpyrrolidone;

[0031] Test 4): Omeprim and sulfadiazolidine were mixed and dissolved in a solvent system consisting of N-methylpyrrolidone and triethanolamine;

[0032] It is inferred that omeprim (weakly basic) and sulfadiazolidine (weakly acidic) may be able to form salts in N-methylpyrrolidone, thereby significantly increasing the solubility of omeprim in N-methylpyrrolidone. At the same time, omeprim-sulfadiazol can be stably dissolved in an alkaline solvent system containing triethanolamine.

[0033] Experiment 5): After adding ormeprim to N-methylpyrrolidone, equimolar amounts of acetic acid / lactic acid were added to form a salt, which was soluble in N-methylpyrrolidone. Sulfadimethoxine and triethanolamine were subsequently added to the system, and the solubility of each component was not affected.

[0034] Experiment 6): After adding N-methylpyrrolidone to sulfadiazolidine, an equimolar amount of triethanolamine was added to form a salt; ormeprim was dissolved in this system after ultrasound.

[0035] 2. Determination of process

[0036] Based on the above test results, three preparation processes of sulfadiazolidine / olmeprim solutions were designed. The excipients and formula amounts are detailed in Table 2:

[0037] Table 2 Process research prescription design (per 100mL)

[0038]

[0039] Note: In the table, SDM stands for sulfadiazolidine; OMP stands for ormeprim; TEA stands for triethanolamine; NMP stands for N-methylpyrrolidone; and LA stands for lactic acid. The TEA content used is 85%, and the amounts used in the table refer to 85% TEA. The same applies to the following tables.

[0040] Process 1: Weigh 2.5g of ormeprim and 12.5g of sulfadimethoxine in a beaker, add 20mL of N-methylpyrrolidone to dissolve most of the drugs, then add 20g of triethanolamine and stir until the drugs are completely dissolved. After the drugs are completely dissolved, add 3.8g of lactic acid to form a salt with the remaining triethanolamine in the system to form an alkaline buffer system, and then use N-methylpyrrolidone to adjust the volume to 100mL. The drugs in the solution system prepared by this process exist in the form of ormeprim-sulfadimethoxine and triethanolamine-sulfadimethoxine.

[0041] Process 2: Weigh 12.5g of sulfadimethoxine in a beaker, add 20mL of N-methylpyrrolidone to dissolve the drug, add 22g of triethanolamine to form a salt with sulfadimethoxine, and stir until the drug is completely dissolved. After the drug is completely dissolved, add 3.8g of lactic acid, form a salt with the remaining triethanolamine in the system to form an alkaline buffer system, and stir evenly. Afterwards, add 2.5g of ormeprim, stir and ultrasonicate (40kHz, 5min) until dissolved, and use N-methylpyrrolidone to make the volume 100mL. The drug in the solution system prepared by this process exists in the form of triethanolamine-sulfadimethoxine and ormeprim, and ormeprim is not salted.

[0042] Process 3: Weigh 2.5g of oromeprim in a beaker, add 20mL of N-methylpyrrolidone, stir evenly, add 0.8g of lactic acid to form a salt with oromeprim, stir and ultrasonicate (40kHz, 20min) until the drug is completely dissolved. Weigh 12.5g of sulfadimethoxine and add it to the above solution system, stir until most of the drug is dissolved, add 22g of triethanolamine to form a salt with sulfadimethoxine, stir until the drug is completely dissolved, add 3.8g of lactic acid to form a salt with the remaining triethanolamine in the system to form an alkaline buffer system, stir evenly, and use N-methylpyrrolidone to make the volume to 100mL; the drug in the solution system prepared by this process exists in the form of oromeprim-organic acid and triethanolamine-sulfadimethoxine.

[0043] Given that the mass ratio of sulfadimethoxine to ormeprim in the solution system is 5:1, the primary consideration when selecting the buffer system's acidity and alkalinity is the stability of sulfadimethoxine's dissolution. Since sulfadimethoxine exists as triethanolamine-sulfadimethoxine, an alkaline buffer system was selected. The ormeprim-organic acid formed in process three may be unstable in an alkaline buffer, and the organic acid needs to be added in two stages during the preparation process, increasing the complexity of the process. Therefore, process three was not further investigated in subsequent formulation screening.

[0044] Example 2 Screening of the Prescription of Sulfadimethoxine and Omeprim Compound Solution

[0045] 1. Determination of pH of alkaline buffer system

[0046] The alkaline buffer system consists of triethanolamine and triethanolamine-organic acid salts formed by triethanolamine and organic acids. The pH at different molar ratios of base and salt can be calculated based on the Henderson–Hasselbach equation and the pKa of triethanolamine (7.76). A weakly alkaline solution system favors the stable dissolution of sulfadiazolidine in it. Therefore, the molar ratio of triethanolamine to triethanolamine-organic acid was set to 1, resulting in a solution pH of 7.76. The amounts of each excipient in the buffer system were calculated based on the molecular weights of triethanolamine, lactic acid / acetic acid, the target pH of the buffer system, and the dosage limits of the excipients in the formulation. The buffering capacity of the buffer solution is determined by the concentrations of triethanolamine and triethanolamine-organic acid in the solution. Given that the sulfadiazolidine / solution needs to be diluted approximately 1500-fold for clinical administration, the alkaline buffer system is present at a higher concentration in the solution to ensure adequate buffering capacity after mixing with water. The amounts of excipients required to constitute the buffer system are detailed in Table 3.

[0047] Table 3 Amounts of excipients for alkaline buffer system (per 100 mL)

[0048]

[0049] The pH of tap water varies from region to region, ranging from acidic to alkaline. To examine the buffering capacity of buffer systems 1 and 2, two laboratory-prepared sulfadiazolidine / ormeprim solutions were prepared according to the formulation and process described in Table 4. One liter of Yangzhou tap water (pH = 7.62) was placed in a beaker and the pH measured. An equal volume of tap water was then adjusted to approximately pH 6.5 with acetic acid. 0.6 mL of either formulation 1 or formulation 2 was added to each 1 L of tap water. After stirring with a glass rod, the pH was measured again. The results are shown in Table 5.

[0050] Table 4 Buffer system buffer capacity test prescription (per 100mL)

[0051]

[0052] Table 5 Results of investigation on buffer capacity of buffer system

[0053]

[0054] The results showed that in the presence of alkaline buffer systems 1 and 2, sulfadiazolidine / olmeprim solution had good buffering capacity for acidic tap water, and could keep the drinking water in a weak alkaline state after mixed drinking; while for alkaline tap water, the pH of the drinking water would increase after administration.

[0055] The presence of an alkaline buffer system significantly improves the solubility stability of sulfadimethoxine and ormeprim in water after the formulation is mixed with water. Sulfadimethoxine-ormeprim solutions with or without an alkaline buffer system were prepared according to the formulation and process described in Table 6. 0.6 mL of each solution was added to a 1 L glass beaker containing 1 L of alkaline or acidic tap water, respectively. The solution was stirred evenly and allowed to stand at room temperature for 10 minutes. 1 mL of the solution was then sampled using a Pasteur pipette from the upper (900 mL), middle (500 mL), and lower (100 mL) points of the tap water. After appropriate pretreatment, the peak areas of sulfadimethoxine and ormeprim were determined using high-performance liquid chromatography. Each batch of samples was subjected to point calibration using a calibration standard with similar concentrations. The concentrations of sulfadimethoxine and ormeprim in the tap water were calculated. Details of the pretreatment and chromatographic testing conditions are shown in Table 7.

[0056] Table 6 Effect of alkaline buffer system on the stability of SDM and OMP in tap water

[0057]

[0058] Table 7 HPLC method for determination of sulfadiazolidine and omepramine concentrations in water

[0059]

[0060] The concentrations of sulfadiazolidine and ormeprim in the water at 0h and 48h after the three prescriptions were mixed with acidic (pH=6.53) and alkaline (pH=7.62) tap water are shown in Table 8.

[0061] Table 8 Results of investigation on the effect of alkaline buffer system on the mixture of preparation and water

[0062]

[0063] Note: N = 3. The measured concentration is the concentration of the sample after dilution 5 times; the deviation refers to the difference between the measured concentration of the drug at 48 hours in water and the measured concentration at 0 hours, the same below.

[0064] The results showed that after mixing Recipes 1 and 3 with acidic and alkaline tap water in the prescribed proportions, the coefficients of variation of the measured concentrations of sulfadiazolidine and omeprazole were all less than 5% at both 0 and 48 hours, indicating that the drugs were evenly dispersed after mixing with water. In acidic tap water, the concentration deviations of both Recipes 1 and 3 after mixing with water were less than 15% at 48 hours. In alkaline tap water, the concentration deviations of both drugs in Recipe 1 at 48 hours were close to -50%, nearly halving the drug concentrations, while the concentration deviation of Recipe 3 at 48 hours was less than 15%. Recipe 4, which did not include an alkaline buffer system, showed a 48-hour concentration deviation of sulfadiazolidine less than 15% in both acidic and alkaline tap water, with coefficients of variation less than 7% at 0 and 48 hours, but omeprazole did not dissolve stably. These results demonstrate that in the presence of an alkaline buffer system, both sulfadiazocine and ormeprim solutions prepared from Formulations 1 and 3 remain stably dissolved in acidic tap water for at least 48 hours. While Formulation 1 exhibits poor stability in alkaline tap water, Formulation 3 exhibits good stability in this same environment. Furthermore, the alkaline buffer system has minimal effect on the dissolution of sulfadiazocine after mixing with water, but significantly improves the stability of ormeprim in water. The impact of process factors on the dissolution stability of sulfadiazocine and ormeprim will be further investigated during formulation optimization.

[0065] 3. Screening of diluent

[0066] N-Methylpyrrolidone is an aprotic solvent that is slightly soluble in water, low-molecular-weight alcohols, ketones, polyethylene glycol, and other solvents such as ethyl acetate, chloroform, and benzene. This study screened common solvents approved for use as pharmaceutical excipients in China based on the formulations and processes described in Table 9. The clarity of the solutions was assessed upon initial preparation and after 48 hours at room temperature according to the "Chinese Pharmacopoeia General Chapter 0902 Clarity Test Method." Formulations with a "clear" result were selected as preliminary formulations.

[0067] Table 9 Diluent Screening Test Prescription (per 100 mL)

[0068]

[0069] Note: DMSO refers to dimethyl sulfoxide, the same as in the following table; 50% propylene glycol refers to 50% propylene glycol aqueous solution.

[0070] The results show (Table 9) that when using process 1 and process 2, N-methylpyrrolidone and dimethyl sulfoxide as diluents can maintain clarity at the time of preparation and after 48 hours. Propylene glycol is a latent solvent and can exert the best solubility when mixed with water in a certain proportion. Based on the previous investigation of the solubility and stability of propylene glycol aqueous solutions after mixing with drugs and excipients in different proportions, 50% propylene glycol aqueous solution was selected as the diluent. However, when propylene glycol, 50% propylene glycol aqueous solution and anhydrous ethanol were used as diluents, although they were clear when initially prepared, they all produced obvious white precipitates and gradually became turbid after being placed at room temperature for 48 hours; pure water produced obvious white precipitates when the preparation was completed. In summary, N-methylpyrrolidone and dimethyl sulfoxide were selected as diluents, that is, prescriptions 1, 3, 9 and 10 were selected as the preferred prescriptions.

[0071] Example 3 Optimization of the prescription of sulfadiazolidine and omepramine compound solution

[0072] Based on the excipient composition and dosage obtained from the above-mentioned formulation screening, as well as the process research results, an orthogonal experiment was designed to screen for the optimal combination. According to the orthogonal experimental design, a three-factor, two-level orthogonal experiment was conducted with the diluent, preparation process, and buffer concentration. The stability of the formulation after mixing with tap water (alkaline) (0.6 mL to 1 L of water) was examined under different factor level combinations to screen for the most optimal process and excipients. The experimental factor level table is shown in Table 10, and the orthogonal experiment results are shown in Table 11.

[0073] Table 10 Experimental factor level table

[0074]

[0075] Table 11 Orthogonal experimental design scheme and experimental results

[0076]

[0077]

[0078] Range calculations show that for the stability of OMP and SDM after 24 hours of mixing with water, the factors C > A > B; for the stability of OMP and SDM after 48 hours of mixing with water, the factors A > B > C. Based on the orthogonal test results, using the stability of the two drugs after 24 and 48 hours of mixing with water as evaluation indicators, the optimal formulation and process are A1B1C2 (see Table 12 for details).

[0079] Table 12 Final formulation and preparation process

[0080]

[0081] Example 4 Stability Study of Compound Solutions of Sulfadiazol and Omeprim at Different Concentrations

[0082] Based on the obtained 12.5%-2.5% sulfadimethoxine and omepramine compound solutions, a formulation was designed based on the same principles and process (the 12.5%-2.5% formulation and preparation process were the same as in Table 12 of Example 3) to explore the feasibility of preparing higher concentration solutions using the current formulation and process. Compound solutions of sulfadimethoxine and omepramine were prepared at different concentrations ranging from 15% to 25% (calculated as sulfadimethoxine) according to the formulation described in Table 13.

[0083] Table 13 Prescriptions for different concentrations of sulfadiazolidine and omeprazole compound solutions (per 100 mL)

[0084]

[0085] Under the current prescription and process, prescriptions 15 and 16 can both prepare clear solutions. Due to the large amount of drug, a small amount of drug cannot be completely dissolved in the solution prepared according to prescription 17. Without increasing the amount of solvent, doubling the concentration of the alkaline buffer system, that is, prescription 18, can prepare a clear solution, but the increase of triethanolamine makes the solution fluidity poor, clinical administration is not convenient and easily leads to errors in the administration volume. Therefore, although highly concentrated compound solutions have the advantage of reducing the volume of single use, they lack practicality. After the three concentrations of solutions are mixed with tap water, the drugs can be stably dissolved in water for 48 hours, with good water mixing stability. Although the concentration of the main drug in the solution system has doubled compared to the 12.5% ​​prescription, the amount of solvent and excipients constituting the alkaline buffer system remains unchanged except for the 25% solution. Due to the increase in the concentration of sulfadimethoxine, the amount of triethanolamine used for salt formation needs to be increased. When 5g of sulfadimethoxine and 1g of ormeprim are added to every 100mL, the amount of triethanolamine needs to be increased by about 2g. In addition, due to the increase in the amount of the main drug, prescriptions 16 and 17 require ultrasonic dissolution when dissolving the main drug. Under the conditions of the small ultrasonic instrument used in the laboratory, ultrasonication is required for at least 1 hour, which is not suitable for industrial production. After preparation, the mixture was placed in the dark at room temperature for 10 days. The compound solutions of sulfadimethoxine and ormeprim with four different concentrations are shown in FIG. Figure 1 .

[0086] Example 5 Prescription Screening of 12.5%-7.5% Sulfadimethoxine and Omeprim Compound Solution

[0087] Sulfonamides and their synergists are often used in a 5:1 ratio to prepare compound preparations. Approved preparations in my country include sulfadiazine suspension produced by Virbac, France. Compound preparations, including compound sulfamethoxazole tablets and compound sulfachloropyridazine powder produced by domestic enterprises, all use this ratio. However, the compound preparations of sulfadimethoxine and ormeprim approved in the United States include preparations with sulfadimethoxine and ormeprim in ratios of 5:1 and 5:3. Therefore, based on the formulation and process developed for the 5:1 ratio, the present invention further developed a formulation and process for a 5:3 ratio.

[0088] Since the concentration of omeprim increased threefold, the amount of solvent N-methylpyrrolidone (NMP) was increased from 20 mL / 100 mL to 30 mL / 100 mL to ensure complete drug dissolution. Furthermore, unlike the 5:1 solution preparation process, omeprim cannot be pre-mixed with sulfadimethoxine; sulfadimethoxine must be added only after it is completely dissolved in N-methylpyrrolidone. When the sulfadimethoxine concentration remains unchanged while the omeprim concentration increases, the pH of the buffer system may need to be altered compared to the 5:1 solution. Therefore, the pH of the buffer system was first investigated based on the formulation described in Table 14.

[0089] Table 14 Acidity and alkalinity of 5:3 preparation buffer solution (per 100 mL)

[0090]

[0091]

[0092] The results showed that a large amount of white crystals precipitated during initial preparation in an alkaline buffer system. A clear and stable compound solution could be prepared in an acidic buffer system. In the absence of a buffer system, the solution was stable upon initial preparation, but with prolonged standing time, the precipitation of white crystals gradually increased. Based on this, it is speculated that the main drug dissolves more stably in an acidic buffer system at a 5:3 ratio.

[0093] Based on the acidic buffer system, the pH of the buffer system was further studied. After the triethanolamine in prescription 19 formed a salt with sulfadiazolidine, the remaining amount reacted with lactic acid to form triethanolamine-lactate. The triethanolamine-lactate formed and the equimolar remaining lactic acid formed an acidic buffer system. According to the Henderson–Hasselbach formula, the pH of this buffer system was calculated to be equal to the pKa value of lactic acid (3.86). To further study acidic buffer systems with different pH and concentrations, a parallel experimental design was used, using acetic acid (pKa = 4.75), which is weaker than lactic acid, to replace lactic acid. The specific research prescriptions are shown in Table 15. The acidic buffer system concentrations of prescriptions 23 and 24 were twice that of prescriptions 19 and 22, respectively.

[0094] Table 15 Acidic buffer system research prescription (per 100mL)

[0095]

[0096] The results showed that all four prescriptions could prepare clear compound solutions when first prepared. However, prescriptions 22 and 23 quickly developed white crystalline precipitates when left at room temperature, and prescription 24 developed a small amount of precipitate after one week. The properties of the solutions prepared by the four prescriptions became different after being left at room temperature for 10 days. Figure 2 These results indicate that, at a 5:3 ratio, the pH and concentration of the buffer system significantly affect the stability of the solution of the active ingredients sulfadiazolidine and omepramine. High concentrations in a buffer system with a higher acidity, and low concentrations in a buffer system with a lower acidity, prevent the active ingredients from dissolving stably. Based on these findings, Formulation 19 was selected as a pre-formulation to further investigate its stability after mixing with water.

[0097] Due to the increased content of omeprim, the proposed clinical dosage at a 5:3 ratio is lower than that at a 5:1 ratio, tentatively set at 62.5 μg / mL water. When using a 12.5%-7.5% compound solution, 0.5 mL of the solution is added to 1 L of Yangzhou tap water (pH = 7.62). The stability of Prescription 19 after mixing with water was investigated according to the method described in Example 2. The measured concentrations at 0 h, 12 h, 24 h, and 48 h after mixing are shown in Table 16. The results show that after Prescription 19 was mixed with water, the measured concentrations of sulfadiazolidine and omeprim at each sampling time were within ±15% of the theoretical values, indicating that the drugs can be stably dissolved in tap water for at least 48 h, meeting the requirements of clinical use.

[0098] Table 16 Actual drug concentrations of prescription 19 after mixing with tap water according to the clinical dosage

[0099]

[0100] During testing, it was found that after mixing with water, the solution of Formulation 19 initially transformed into a white, spider-web-like solid. This solid dissolved completely after stirring or allowing it to stand for a period of time. Compared to the 5:1 formulation, the drug took longer to disperse after mixing with water. The same phenomenon occurred with Formulations 22, 23, and 24 when added to water, suggesting this may be related to the acidic nature of the solution.

[0101] Example 6 Anticoccidial Index of Sulfadimethoxine and Omeprim Compound Solution in Target Animal Chicken

[0102] Final evaluation of the formulation based on preclinical and clinical study results is an important step in formulation screening and optimization. The sulfadimethoxine and ormeprim compound solution prepared by the present invention is intended for use in veterinary clinical settings to control coccidiosis and bacterial diseases in chickens. The anticoccidial index (ACI) is an important indicator for evaluating the efficacy of anticoccidial drugs. To further evaluate the final formulation, a final formulation of 12.5%-2.5% sulfadimethoxine and ormeprim compound solution (i.e., the formulation described in Table 12) was selected. A preliminary evaluation was conducted on the efficacy of the compound sulfadimethoxine solution, mixed with water at a dose of 37.5 mg / L (calculated as sulfadimethoxine), against artificially infected chickens with Eimeria tenella. Further pharmacodynamic studies will be conducted on target chickens using different concentrations of sulfadimethoxine and ormeprim compound solution mixed with water to control infections with sensitive bacteria and coccidia.

[0103] 1. Test method

[0104] 1) Experimental drugs

[0105] Sulfadimethoxine and ormeprim combination solution: prepared in the laboratory, with a sulfadimethoxine concentration of 12.5% ​​and ormeprim concentration of 2.5%.

[0106] 2) Experimental animals

[0107] One-day-old healthy AA broiler chickens without coccidial infection were fed a feed without anticoccidial drugs and antibiotics (provided by Suzhou Shuangshi Experimental Animal Technology Co., Ltd.).

[0108] 3) Grouping and attacking insects

[0109] Before the challenge, 30 AA broilers were randomly divided into three groups based on body weight: a negative group (no challenge and no drug), a positive group (no drug after challenge), and a drug group (drug administration 48 hours after challenge). The body weight at the time of grouping was recorded. When the chicks were fed to 14 days of age, 1 mL (10×10 4 / mL).

[0110] 4) Dosage regimen

[0111] Both the negative and positive groups received drug-free feed and drinking water during the experiment. The drug group began administering the drug in mixed drinking water 48 hours after challenge. The medicated drinking water was prepared as follows: 1.5 mL of a combined solution of sulfadimethoxine and ormeprim was added to 5 L of tap water, stirred with a glass rod for 5 minutes, and allowed to stand at room temperature for 5 minutes before use. The drug group received the medicated drinking water continuously for 4 days. Freshly prepared medicated drinking water was provided daily during the dosing period, and drinking water was replenished promptly. The concentrations of sulfadimethoxine and ormeprim in the daily medicated drinking water were measured according to the method described in Example 2.

[0112] 5) Observation indicators

[0113] During the experiment, the mental state, diet, defecation and death of chickens were observed and recorded every day.

[0114] 6) Bloody stool count

[0115] The bloody stools of each group were observed and counted at 96h, 108h, 120h, 132h, 144h, 156h, 168h and 180h after infection.

[0116] 7) ACI calculation

[0117] On the 9th day after infection, all test chickens were weighed and dissected. Cecal lesions were observed and scored. The oocysts were counted and the OPG value was calculated. The ACI value was calculated according to the following formula:

[0118] ACI = (survival rate + relative weight gain rate) - (lesion value + oocyst value)

[0119] ACI above 180 is high efficiency; 160-180 is medium efficiency; 120-160 is low efficiency; and below 120 is poor.

[0120] 8) Statistical analysis

[0121] In SPSS26.0 software, Duncan's new multiple range method was used to perform statistical analysis on the weight gain and lesion scores of chickens in each experimental group, with a significance level of 0.05.

[0122] 2. Test results

[0123] 1) Drug concentration in drinking water

[0124] During the trial, the day of the parasite attack was defined as Day 1. The daily concentrations of sulfadimethoxine and ormeprim in the drinking water of the drug group are shown in Table 17. The test results showed that the average daily concentrations of sulfadimethoxine in the drug-containing drinking water ranged from 39.30 to 41.66 mg / L, and the concentrations of ormeprim ranged from 7.84 to 8.37 mg / L. The deviations from the theoretical concentrations (sulfadimethoxine 37.5 mg / L, ormeprim 7.5 mg / L) were both within ±15%, indicating that the sulfadimethoxine and ormeprim combination solution, at the current dosage, exhibited good stability in drinking water during clinical administration.

[0125] Table 17 Drug concentration determination results in drinking water during administration

[0126]

[0127] 2) Bloody stool count

[0128] During the trial, bloody stool counts in each test group at different time points after parasitization are shown in Table 18. The negative group showed no bloody stools at any time point after parasitization, demonstrating the reliability of the test system. Furthermore, the number of bloody stools in the drug group was smaller than that in the positive group at all time points, and the duration of bloody stools was shorter than that in the positive group. This indicates that the sulfadiazolidine and omeprazole solution, when mixed and administered at the current dosage, is effective in alleviating bloody stools caused by coccidia infection in chickens.

[0129] Table 18 Bloody stool count results

[0130]

[0131] 3) Statistical analysis of weight gain and lesion scores

[0132] During the experimental period, the average body weight, weight gain, and lesion score of each group are shown in Table 19. Statistical analysis showed that there were no significant differences in the initial body weight of the animals among the groups (P ≥ 0.05). There were no significant differences in the final body weight, weight gain, and lesion score between the positive control group and the drug group (P ≥ 0.05). However, there were significant differences between the negative control group, the drug group, and the positive control group (P < 0.05). These results indicate that coccidia infection significantly affects the body weight, weight gain, and cecal lesions of chickens, and that the current experimental system is reliable.

[0133] Table 19 Average body weight and weight gain and lesion score results (mean ± standard deviation, N = 10)

[0134]

[0135]

[0136] Note: The same superscripts indicate no significant difference (P≥0.05), and different superscripts indicate significant difference (P<0.05).

[0137] 4) ACI calculation

[0138] ACI and the parameter values ​​for calculating ACI are shown in Table 20.

[0139] Table 20 ACI and the parameter values ​​for calculating ACI

[0140]

[0141] The ACI calculation results showed that the ACI value of the combined solution of sulfadimethoxine and omeprazole was 164 when continuously administered as a mixed drink at a concentration of 37.5 mg / L (calculated as sulfadimethoxine) for 4 days, indicating a moderate anticoccidial effect.

[0142] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A sulfonamide-antibacterial synergist compound solution, characterized in that: Each 100 mL of the compound solution contains 12.5 g of sulfadiazolidine, 2.5 g of ormeprim, 20 mL of N-methylpyrrolidone, 20-22 g of triethanolamine, 3.8 g of lactic acid or 2.5 g of acetic acid, and dimethyl sulfoxide or N-methylpyrrolidone to make up to 100 mL. The compound solution is prepared by the following method: at room temperature, sulfadiazolidine and ormeprim are mixed, N-methylpyrrolidone is added to dissolve most of the drugs; triethanolamine is added, and stirring / ultrasound is performed until the drugs are completely dissolved; lactic acid or acetic acid is added and mixed uniformly; N-methylpyrrolidone or dimethyl sulfoxide is added to make up the volume, thereby obtaining a sulfonamide-antibacterial synergist compound solution.

2. The method for preparing the sulfonamide-antibacterial synergist compound solution according to claim 1, characterized in that: The method comprises the following steps: mixing sulfadiazolidine and ormeprim at room temperature, adding N-methylpyrrolidone to dissolve most of the drugs; adding triethanolamine, stirring / ultrasounding until the drugs are completely dissolved; adding lactic acid or acetic acid and mixing evenly; and adding N-methylpyrrolidone or dimethyl sulfoxide to adjust the volume to obtain a sulfa drug-antibacterial synergist compound solution.

3. Use of the sulfonamide-antibacterial synergist compound solution according to claim 1 in the preparation of a medicament for preventing and / or treating Eimeria tenella infection in animals.

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