Sulfamethoxypyrazine sodium methenamine suspension and its preparation method and application

Abstract

The present application relates to the technical field of pharmaceutical preparation, in particular to a sulfachloropyrazine sodium ampicillin suspension, a preparation method and application thereof. The sulfachloropyrazine sodium ampicillin suspension of the present application, per 100ml of the suspension, is composed of the following components: sulfachloropyrazine sodium 20-50g, ampicillin 4-10g, suspending agent 0.1-0.25g, wetting agent 0.05-0.125g, antioxidant 0.2-0.5g, edetic acid disodium 0.1-0.25g, and purified water to 100ml. The suspension prepared by the present application can delay the in-vivo clearance of sulfachloropyrazine sodium, prolong the synergistic action time, and improve the bioavailability thereof; in the treatment of chicken and sheep coccidiosis, the suspension can significantly improve the weight gain rate, reduce the intestinal lesion value, quickly remove the oocysts, and maintain a long-lasting protective effect after drug withdrawal.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical preparation technology, specifically to a sulfachlorpyridazine sodium methotrexate suspension, its preparation method and application, and further to the application of sulfachlorpyridazine sodium methotrexate suspension in the treatment of coccidiosis in chickens and sheep. Background Technology

[0002] Parasitic diseases are a significant group of diseases affecting animal husbandry, posing a serious threat to animals. Chicken coccidiosis (…) Coccidiosis Coccidiosis is a parasitic disease of poultry caused by one or more coccidia that parasitize the epithelial cells of the chicken intestine. Among various chicken diseases, coccidiosis has the highest incidence rate. It primarily affects chickens under three months old, with the most severe impact on chicks aged 15-50 days. In adult chickens, it significantly affects egg production and weight gain. The morbidity and mortality rates in chicks aged 10-30 days or young chickens aged 35-60 days can reach as high as 80%, significantly reducing the economic benefits for farmers. The annual economic loss due to coccidiosis is estimated at $3 billion, causing severe economic damage to the global poultry industry. Furthermore, infection with *Eimeria tenella* significantly increases the likelihood of Salmonella infection, prolongs the time Salmonella is released into the environment, and can lead to increased Salmonella contamination in eggs. Eimeriidae Eimeria ( ) Eimeria Coccidiosis is a self-limiting parasitic disease caused by coccidiosis and is widespread worldwide. Sheep have a high infection and morbidity rate, regardless of age or breed; the infection rate in lambs aged 1-3 months can reach 94.5%. Because coccidiosis can damage the integrity of the digestive tract mucosa and affect nutrient absorption, lambs infected with Eimeria coccidiosis often present with diarrhea, dehydration, stunted growth, anemia, emaciation, rough coat, and even death. Adult sheep are long-term carriers and transmitters; mild infections generally do not show obvious clinical symptoms, but prolonged infection can lead to secondary infections. Coccidiosis is most harmful to weaned lambs; if not properly controlled, it can lead to mass lamb deaths and cause serious economic losses to the livestock industry. Therefore, the direct harm and chain of negative effects of coccidiosis are extremely detrimental to public health, the environment, and the economy.

[0003] Currently, the main treatments for coccidiosis are vaccines and anticoccidial drugs, but the stability, relapse toxicity, and cost-effectiveness of vaccines need improvement. Antibiotics: (1) Polyether ionocarrier drugs, such as monensin, salinomycin, doramectin, and laxamycin, mainly act on the asexual reproductive stage, by changing the permeability of the cell membrane and the concentration of cations inside and outside the insect, disrupting the osmotic pressure balance and thus killing coccidia sporozoites and trophozoites. However, some antibiotics have a narrow antibacterial spectrum and significant toxic side effects; (2) Pyridine drugs, which are effective against coccidia. E.tenellaThe effects are significant, with good effects on spore reproduction and schizogenes, and are mainly used for preventive administration; (3) Sulfonamides, including sulfadiazine, sulfamethoxypyrimidine, etc., are mainly effective for asexual reproduction, reducing the activity of dihydrofolate synthase, blocking folic acid metabolism, and reducing coccidia reproduction. However, these drugs cannot be used for a long time, are highly toxic, and are prone to drug residues; (4) Triazines, such as diclazuril, toltrazuril, etc., are broad-spectrum anticoccidial drugs that can kill various coccidia and have an inhibitory effect on various reproductive stages. However, with excessive use, drug-resistant coccidia strains appear, causing degradation of proteins and various enzymes in the oocysts. At this time, the killing effect of anticoccidial drugs on the oocysts is weakened. The emergence of drug residues and drug resistance makes it imperative to develop and research a new generation of broad-spectrum, highly effective, safe and low-toxic animal-specific antibacterial drugs.

[0004] Sulfachloropyrazine sodium is an animal-specific sulfonamide anticoccidial drug with good inhibitory effects on coccidiosis in poultry, sheep, and rabbits. Its peak action occurs in the second-generation schizonts of coccidia, but it also has some effect on the first-generation schizonts. The mechanism of action of sulfachloropyrazine sodium is similar to other sulfonamides; it can replace para-aminobenzoic acid (PBPA), a necessary component for protozoan and bacterial metabolism, to form pseudofolate, and compete with PBPA for dihydrofolate synthase, inhibiting dihydrofolate synthesis. This indirectly inhibits tetrahydrofolate synthesis, thereby suppressing the synthesis of purines, pyrimidines, and nucleotides, thus hindering nucleic acid synthesis and inhibiting the growth and reproduction of bacteria and protozoa. Due to long-term use, coccidia have developed some resistance to sulfachloropyrazine sodium; therefore, in clinical applications, it is often used in combination with sulfonamide potentiators to improve the anticoccidial efficacy.

[0005] Aditoprime (ADP) is a novel class of animal-specific antibacterial potentiators, chemically named 5-(4-dimethylamino-3,5-dimethoxyphenyl)methyl-2,4-diaminopyrimidine. It possesses advantages such as a broad antibacterial spectrum and a long half-life. Studies have shown that ADP's most prominent pharmacokinetic characteristic is its significant long-lasting effect. Under intravenous injection conditions, the elimination half-life of ADP in normal sheep is as long as 18.33±5.24 h, and it remains at 13.83±4.34 h even under febrile conditions (Iqbal MP et al., 1995). In buffalo calves, the elimination half-life is 6.14 h, approximately twice that of TMP (3.08 h) (Iqbal MP et al., 1994). In comparison, the half-life of TMP in sheep is only 0.77 ± 0.33 h (Iqbal MP et al., 1990), while in chickens, pigs, and tilapia it is 2.51 h (Zhang et al., 2015), 4.093 h (Song et al., 2020), and 5.99 h (Xiao et al., 2014), respectively; the half-life of DVD in chickens is 8.03 h (Hao et al., 2011). These results indicate that the elimination half-life of ADP in sheep is approximately 20 times that of TMP, demonstrating significant advantages in long-lasting effect and wider tissue distribution.

[0006] However, there are currently no reports on the formulation of a stable aqueous suspension by combining ADP with sulfachlorpyridazine sodium. While sulfachlorpyridazine sodium is highly water-soluble, its synergist, methotrexate, is insoluble in water. This difference in water solubility inevitably leads to difficulties in uniform dispersion during use, resulting in inconsistent absorption rates in animals after administration. Furthermore, it cannot guarantee a uniform ratio of the active ingredient and the synergist. Therefore, the development of a sulfachlorpyridazine sodium-methotrexate suspension is of great significance for improving the existing problem of coccidiosis resistance. Summary of the Invention

[0007] This invention provides a sulfachlorpyridazine sodium methotrexate suspension, its preparation method, and its application. The aim is to overcome the water insolubility of methotrexate, and to prepare a sulfachlorpyridazine sodium methotrexate suspension that is convenient for storage, transportation, and use; simultaneously, by using ultrafine grinding to reduce the drug particle size, the stability of the drug is further ensured, and the release of the drug in livestock and poultry is improved, thereby enhancing its efficacy.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: A sulfachlorpyridazine sodium-metazoline suspension, each 100ml of suspension is composed of the following components: 20-50g sulfachlorpyridazine sodium, 4-10g metazoline, 0.1-0.25g suspending agent, 0.05-0.125g wetting agent, 0.2-0.5g antioxidant, 0.1-0.25g metal chelating agent, and solvent to a final volume of 100ml.

[0009] Preferably, a sulfachlorpyridazine sodium-methabenline suspension comprises the following components per 100 ml: 20-40 g of sulfachlorpyridazine sodium, 4-8 g of methabenline, 0.1-0.125 g of suspending agent, 0.05-0.1 g of wetting agent, 0.2-0.5 g of antioxidant, 0.1-0.25 g of metal chelating agent, and solvent diluted to 100 ml.

[0010] The metal chelating agent is disodium edetate.

[0011] The solvent is purified water.

[0012] The particle size of the methomyl is ≤15μm.

[0013] The suspending agent is one of xanthan gum, sorbitol, agar, and sodium carboxymethyl cellulose.

[0014] The wetting agent is one of glycerin, Tween-80, or poloxamer 188.

[0015] The antioxidant is one of anhydrous sodium sulfite and sodium thiosulfate.

[0016] A method for preparing a sodium sulfachlorpyridazine and methotrexate suspension is as follows: (1) Weigh the prescribed amount of purified water, stir continuously at 500 rpm, heat to 40°C and keep warm; (2) Add the suspending agent to the purified water and stir continuously for 1 hour to dissolve it completely; (3) Add the wetting agent, antioxidant and metal chelating agent, stir for 10 minutes to dissolve it completely; (4) Add methotrexate (particle size ≤15μm) and stir for 10 minutes; (5) Add sodium sulfachlorpyridazine and stir for 10 minutes; (6) After adjusting the volume of the above system, set the speed of the emulsifying homogenizer shear to 4000 rpm and shear the above material for 30 minutes.

[0017] The above-mentioned sulfachlorpyrifos sodium methotrexate suspension is used in the preparation of anticoccidial drugs for livestock and poultry, wherein the livestock and poultry are sheep and chickens, preferably lambs and young chickens.

[0018] The above-mentioned sulfachlorpyrifos sodium and methotrexate suspension is used in the preparation of anticoccidial drugs for lambs, especially in the preparation of products that improve daily weight gain, reduce mortality, and combat Eimeria aureus in sheep.

[0019] The above-mentioned sulfachlorpyrifos sodium and methotrexate suspension is used in the preparation of anticoccidial drugs for chicks, especially in the preparation of products that improve daily weight gain, reduce mortality, and combat Eimeria tenella.

[0020] The advantages and beneficial effects of this invention are as follows: This invention prepares a suspension with excellent stability by compounding sodium sulfachlorpyrifos with micronized methomyl (particle size ≤15μm) and adding a specific proportion of xanthan gum, Tween-80, and disodium edetate. This suspension overcomes the water insolubility defect of methomyl and has the following outstanding advantages: (1) Good formulation stability Through extensive experiments, this invention has found that when the amount of xanthan gum added is less than 0.1g, the viscosity and structure of the system are insufficient, making it unable to suppress sedimentation; when the amount of xanthan gum added is greater than 0.125g, the viscosity of the system is too high, making it prone to agglomeration at the bottom, which is not conducive to redispersibility; when the amount of Tween-80 added is less than 0.05g, the system is not sufficiently wetted, making it prone to particle agglomeration; when the amount of Tween-80 added is greater than 0.1g, the wetting agent is excessive, which destroys the overall structure of the system and worsens redispersibility. When the ratio of xanthan gum to Tween-80 is less than 2:1, the structure is not sufficiently differentiated, and the sedimentation rate is accelerated. When the ratio is greater than 2.5:1, the particles are not sufficiently wetted, and they are prone to forming compact precipitates, resulting in poor redispersibility. When the ratio is controlled at about 2.0:1 to 2.5:1, the resulting suspension can not only maintain a very high suspension state for a long time (30-day sedimentation volume ratio >0.99), but the sediment is also loose and can be completely redispersed with just a slight shaking. Its overall stability is significantly better than other ratio combinations.

[0021] (2) Significant pharmacokinetic advantages, achieving long-term synergistic effects.

[0022] After oral administration of the suspension of this invention, the elimination half-life of ADP in chickens and sheep was significantly longer than that of trimethoprim (TMP) and dimethoprim (DVD), approximately tens of times (sheep) or several times (chicken) that of TMP, achieving a long-acting level among similar drugs. This allows for sustained maintenance of effective blood drug concentrations and reduces the frequency of administration. The high oral absolute bioavailability of ADP indicates that micronization and a well-designed suspension system significantly improve the dissolution and absorption efficiency of ADP. Compared with sulfachlorpyridazine sodium (SPZ) monotherapy, the peak time and mean residence time of SPZ in the suspension of this invention were significantly prolonged, and the elimination half-life was maintained at a longer level, demonstrating that ADP can delay the absorption and clearance of SPZ, thereby improving the synchronicity of exposure of the two drugs in vivo and significantly prolonging the synergistic effect. Furthermore, the oral absolute bioavailability of SPZ was significantly higher than that of SPZ monotherapy. The apparent volume of distribution of ADP in sheep was much higher than the total body fluid volume, and its tissue distribution was extensive, which is beneficial for achieving effective concentrations at coccidia infection target sites such as the intestines.

[0023] (3) The treatment effect of anticoccidial therapy is superior to that of existing drugs.

[0024] The sulfachlorpyrifos sodium-methamphetamine suspension of this invention is superior to existing sulfonamide monotherapy and its compound preparations with TMP and DVD. In the treatment of Eimeria tenella infection in chickens, the relative weight gain rate of the medium and high dose groups of this invention is close to the level of the healthy control group, the cecal lesion value is reduced by more than 90% compared with the SPZ monotherapy group, the oocyst excretion rate drops to close to the control group level within a few days after administration, and the anticoccidial composite index (ACI) reaches the high-efficiency anticoccidial standard (>180), which is significantly better than SPZ monotherapy and SPZ-TMP and SPZ-DVD compound preparations. In the treatment of coccidiosis in sheep, the suspension of this invention reduced oocysts by over 95% within 3-7 days after administration, with complete clearance of oocysts by day 6. Even after discontinuation of the drug, the oocyst reduction rates remained as high as 91.38% and 83.48% on days 14 and 21, respectively, while the SPZ monotherapy group showed no significant inhibitory effect during the same period. Simultaneously, the relative weight gain rate of lambs in the group treated with this invention was as high as 173.68%, significantly superior to the SPZ monotherapy group (121.88%). These results demonstrate that the suspension of this invention, relying on its excellent pharmacokinetic parameters, achieves a long-lasting anticoccidial effect after a single course of treatment, significantly prolonging the protective period.

[0025] In summary, the sulfachlorpyrifos sodium methotrexate suspension provided by this invention has outstanding advantages in pharmacokinetics, such as long ADP half-life, high bioavailability, significantly prolonged SPZ retention time in vivo, and wide tissue distribution. In terms of pharmacodynamics, it can rapidly take effect on coccidiosis in chickens and sheep, and persistently inhibit oocyst excretion, significantly improve weight gain rate, and reduce intestinal damage, providing a novel drug option for the prevention and treatment of coccidiosis in livestock and poultry. Attached Figure Description

[0026] Figure 1 Mean plasma concentration-time curve of ADP in chicken plasma; Figure 2 Mean plasma concentration-time curve of SPZ in chicken plasma; Figure 3 Mean plasma concentration-time curve of ADP in sheep plasma; Figure 4 Mean plasma concentration-time curve of SPZ in sheep plasma. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, this application will be described in further detail below. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] Example 1

[0029] This embodiment provides a sulfachlorpyrimethanine sodium and methotrexate suspension, with the following formulation and dosage:

[0030] This embodiment also provides a method for preparing a sulfachlorpyrifos sodium methotrexate suspension, the specific steps of which are as follows: (1) Weigh the prescribed amount of purified water, stir continuously at 500 rpm and heat to 40°C and keep warm; (2) Add sodium carboxymethyl cellulose to the purified water and stir continuously for 1 hour to dissolve it completely; (3) Add glycerol, anhydrous sodium sulfite and disodium edetate, stir for 10 minutes to dissolve it completely; (4) Add methotrexate (particle size ≤15μm) and stir for 10 minutes; (5) Add sodium sulfachlorpyrifos and stir for 10 minutes; (6) After adjusting the volume of the above system, set the speed of the emulsifying homogenizer shearing machine to 4000 rpm and shear the above materials for 30 minutes until the solution is well suspended.

[0031] Example 2

[0032] This embodiment provides a sulfachlorpyrimethanine sodium and methotrexate suspension, with the following formulation and dosage:

[0033] This embodiment also provides a method for preparing a sulfachlorpyrifos sodium methotrexate suspension, the specific steps of which are as follows: (1) Weigh the prescribed amount of purified water, stir continuously at 500 rpm and heat to 40°C and keep warm; (2) Add sodium carboxymethyl cellulose to the purified water and stir continuously for 1 hour to dissolve it completely; (3) Add Tween-80, anhydrous sodium sulfite and disodium edetate, stir for 10 minutes to dissolve it completely; (4) Add methotrexate (particle size ≤15μm) and stir for 10 minutes; (5) Add sodium sulfachlorpyrifos and stir for 10 minutes; (6) After adjusting the volume of the above system, set the speed of the emulsifying homogenizer shearing machine to 4000 rpm and shear the above materials for 30 minutes until the solution is well suspended.

[0034] Example 3

[0035] This embodiment provides a sulfachlorpyrimethanine sodium and methotrexate suspension, with the following formulation and dosage:

[0036] This embodiment also provides a method for preparing a sulfachlorpyrifos sodium methotrexate suspension, the specific steps of which are as follows: (1) Weigh the prescribed amount of purified water, stir continuously at 500 rpm and heat to 40°C and keep warm; (2) Add sorbitol to purified water and stir continuously for 1 hour to dissolve it completely; (3) Add Tween-80, anhydrous sodium sulfite and disodium edetate, stir for 10 minutes to dissolve it completely; (4) Add methotrexate (particle size ≤15μm) and stir for 10 minutes; (5) Add sodium sulfachlorpyrifos and stir for 10 minutes; (6) After adjusting the volume of the above system, set the speed of the emulsifying homogenizer shear to 4000 rpm and shear the above materials for 30 minutes until the solution is well suspended.

[0037] Example 4

[0038] This embodiment provides a sulfachlorpyrimethanine sodium and methotrexate suspension, with the following formulation and dosage:

[0039] This embodiment also provides a method for preparing a sulfachlorpyrifos sodium methotrexate suspension, the specific steps of which are as follows: (1) Weigh the prescribed amount of purified water, stir continuously at 500 rpm and heat to 40°C and keep warm; (2) Add xanthan gum to purified water and stir continuously for 1 hour to dissolve it completely; (3) Add Tween-80, anhydrous sodium sulfite and disodium edetate, stir for 10 minutes to dissolve it completely; (4) Add methotrexate (particle size ≤15μm) and stir for 10 minutes; (5) Add sodium sulfachlorpyrifos and stir for 10 minutes; (6) After adjusting the volume of the above system, set the speed of the emulsifying homogenizer shear to 4000 rpm and shear the above materials for 30 minutes until the solution is well suspended.

[0040] Example 5

[0041] This embodiment provides a sulfachlorpyrimethanine sodium and methotrexate suspension, with the following formulation and dosage:

[0042] This embodiment also provides a method for preparing a sulfachlorpyrifos sodium methotrexate suspension, the specific steps of which are as follows: (1) Weigh the prescribed amount of purified water, stir continuously at 500 rpm and heat to 40°C and keep warm; (2) Add xanthan gum to purified water and stir continuously for 1 hour to dissolve it completely; (3) Add Tween-80, anhydrous sodium sulfite and disodium edetate, stir for 10 minutes to dissolve it completely; (4) Add methotrexate (particle size ≤15μm) and stir for 10 minutes; (5) Add sodium sulfachlorpyrifos and stir for 10 minutes; (6) After adjusting the volume of the above system, set the speed of the emulsifying homogenizer shear to 4000 rpm and shear the above materials for 30 minutes until the solution is well suspended.

[0043] Example 6

[0044] This embodiment provides a sulfachlorpyrimethanine sodium and methotrexate suspension, with the following formulation and dosage:

[0045] This embodiment also provides a method for preparing a sulfachlorpyrifos sodium methotrexate suspension, the specific steps of which are as follows: (1) Weigh the prescribed amount of purified water, stir continuously at 500 rpm and heat to 40°C and keep warm; (2) Add xanthan gum to purified water and stir continuously for 1 hour to dissolve it completely; (3) Add Tween-80, anhydrous sodium sulfite and disodium edetate, stir for 10 minutes to dissolve it completely; (4) Add methotrexate (particle size ≤15μm) and stir for 10 minutes; (5) Add sodium sulfachlorpyrifos and stir for 10 minutes; (6) After adjusting the volume of the above system, set the speed of the emulsifying homogenizer shear to 4000 rpm and shear the above materials for 30 minutes until the solution is well suspended.

[0046] Example 7

[0047] This embodiment provides a sulfachlorpyrimethanine sodium and methotrexate suspension, with the following formulation and dosage:

[0048] This embodiment also provides a method for preparing a sulfachlorpyrifos sodium methotrexate suspension, the specific steps of which are as follows: (1) Weigh the prescribed amount of purified water, stir continuously at 500 rpm and heat to 40°C and keep warm; (2) Add xanthan gum to purified water and stir continuously for 1 hour to dissolve it completely; (3) Add Tween-80, anhydrous sodium sulfite and disodium edetate, stir for 10 minutes to dissolve it completely; (4) Add methotrexate (particle size ≤15μm) and stir for 10 minutes; (5) Add sodium sulfachlorpyrifos and stir for 10 minutes; (6) After adjusting the volume of the above system, set the speed of the emulsifying homogenizer shear to 4000 rpm and shear the above materials for 30 minutes until the solution is well suspended.

[0049] Example 8

[0050] This embodiment provides a sulfachlorpyrimethanine sodium and methotrexate suspension, with the following formulation and dosage:

[0051] This embodiment also provides a method for preparing a sulfachlorpyrifos sodium methotrexate suspension, the specific steps of which are as follows: (1) Weigh the prescribed amount of purified water, stir continuously at 500 rpm and heat to 40°C and keep warm; (2) Add xanthan gum to purified water and stir continuously for 1 hour to dissolve it completely; (3) Add Tween-80, anhydrous sodium sulfite and disodium edetate, stir for 10 minutes to dissolve it completely; (4) Add methotrexate (particle size ≤15μm) and stir for 10 minutes; (5) Add sodium sulfachlorpyrifos and stir for 10 minutes; (6) After adjusting the volume of the above system, set the speed of the emulsifying homogenizer shear to 4000 rpm and shear the above materials for 30 minutes until the solution is well suspended.

[0052] Example 9

[0053] This embodiment provides a sulfachlorpyrimethanine sodium and methotrexate suspension, with the following formulation and dosage:

[0054] This embodiment also provides a method for preparing a sulfachlorpyrifos sodium methotrexate suspension, the specific steps of which are as follows: (1) Weigh the prescribed amount of purified water, stir continuously at 500 rpm and heat to 40°C and keep warm; (2) Add xanthan gum to purified water and stir continuously for 1 hour to dissolve it completely; (3) Add Tween-80, anhydrous sodium sulfite and disodium edetate, stir for 10 minutes to dissolve it completely; (4) Add methotrexate (particle size ≤15μm) and stir for 10 minutes; (5) Add sodium sulfachlorpyrifos and stir for 10 minutes; (6) After adjusting the volume of the above system, set the speed of the emulsifying homogenizer shear to 4000 rpm and shear the above materials for 30 minutes until the solution is well suspended.

[0055] Example 10

[0056] This embodiment provides a sulfachlorpyrimethanine sodium and methotrexate suspension, with the following formulation and dosage:

[0057] This embodiment also provides a method for preparing a sulfachlorpyrifos sodium methotrexate suspension, the specific steps of which are as follows: (1) Weigh the prescribed amount of purified water, stir continuously at 500 rpm and heat to 40°C and keep warm; (2) Add xanthan gum to purified water and stir continuously for 1 hour to dissolve it completely; (3) Add Tween-80, anhydrous sodium sulfite and disodium edetate, stir for 10 minutes to dissolve it completely; (4) Add methotrexate (particle size ≤15μm) and stir for 10 minutes; (5) Add sodium sulfachlorpyrifos and stir for 10 minutes; (6) After adjusting the volume of the above system, set the speed of the emulsifying homogenizer shear to 4000 rpm and shear the above materials for 30 minutes until the solution is well suspended.

[0058] Example 11

[0059] This embodiment provides a sulfachlorpyrimethanine sodium and methotrexate suspension, with the following formulation and dosage:

[0060] This embodiment also provides a method for preparing a sulfachlorpyrifos sodium methotrexate suspension, the specific steps of which are as follows: (1) Weigh the prescribed amount of purified water, stir continuously at 500 rpm and heat to 40°C and keep warm; (2) Add xanthan gum to purified water and stir continuously for 1 hour to dissolve it completely; (3) Add Tween-80, anhydrous sodium sulfite and disodium edetate, stir for 10 minutes to dissolve it completely; (4) Add methotrexate (particle size ≤15μm) and stir for 10 minutes; (5) Add sodium sulfachlorpyrifos and stir for 10 minutes; (6) After adjusting the volume of the above system, set the speed of the emulsifying homogenizer shear to 4000 rpm and shear the above materials for 30 minutes until the solution is well suspended.

[0061] Example 12

[0062] This embodiment provides a sulfachlorpyrimethanine sodium and methotrexate suspension, with the following formulation and dosage:

[0063] This embodiment also provides a method for preparing a sulfachlorpyrifos sodium methotrexate suspension, the specific steps of which are as follows: (1) Weigh the prescribed amount of purified water, stir continuously at 500 rpm and heat to 40°C and keep warm; (2) Add xanthan gum to purified water and stir continuously for 1 hour to dissolve it completely; (3) Add Tween-80, anhydrous sodium sulfite and disodium edetate, stir for 10 minutes to dissolve it completely; (4) Add methotrexate (particle size ≤15μm) and stir for 10 minutes; (5) Add sodium sulfachlorpyrifos and stir for 10 minutes; (6) After adjusting the volume of the above system, set the speed of the emulsifying homogenizer shear to 4000 rpm and shear the above materials for 30 minutes until the solution is well suspended.

[0064] Example 13

[0065] This embodiment provides a sulfachlorpyrimethanine sodium and methotrexate suspension, with the following formulation and dosage:

[0066] This embodiment also provides a method for preparing a sulfachlorpyrifos sodium methotrexate suspension, the specific steps of which are as follows: (1) Weigh the prescribed amount of purified water, stir continuously at 500 rpm and heat to 40°C and keep warm; (2) Add sodium carboxymethyl cellulose to the purified water and stir continuously for 1 hour to dissolve it completely; (3) Add Tween-80, anhydrous sodium sulfite and disodium edetate, stir for 10 minutes to dissolve it completely; (4) Add methotrexate (particle size ≤15μm) and stir for 10 minutes; (5) Add sodium sulfachlorpyrifos and stir for 10 minutes; (6) After adjusting the volume of the above system, set the speed of the emulsifying homogenizer shearing machine to 4000 rpm and shear the above materials for 30 minutes until the solution is well suspended.

[0067] Example 14: Quality Evaluation of Sulfachloropyrazine Sodium Methamidoline Suspension

[0068] The sulfachlorpyrifos sodium and methotrexate suspensions prepared in Examples 1-13 were evaluated according to the provisions of the General Rules for Preparations of Veterinary Pharmacopoeia of the People's Republic of China (2020 Edition) under the section on oral suspensions.

[0069] 1. Settlement volume ratio

[0070] Measure 50 ml of the test sample into a stoppered graduated cylinder, seal tightly, shake vigorously for 1 minute, and record the initial height of the suspension. H 0. Let stand for 3 hours, then record the final height of the suspended solids. H Calculate using the following formula: Settlement volume ratio = H / H 0, the settling volume ratio should not be less than 0.90.

[0071] Table 1 Results of sedimentation volume ratio determination

[0072] 2. Redispersibility

[0073] After placing the sulfachlorpyrimethanine sodium and methotrexate suspension in a stoppered graduated cylinder and letting it stand for 24 hours, the graduated cylinder was turned over at a speed of 20 times / min. The number of times it was turned over was observed to see if the sediment at the bottom of the graduated cylinder disappeared.

[0074] Table 2 Results of redispersibility test

[0075] 3. Particle size determination

[0076] Take the sample, shake it well, measure the sample, place it on a glass slide, cover it with a coverslip, and press it gently to distribute the sample evenly, taking care to prevent air bubbles from getting in. Place it on the microscope stage, first observe the uniformity of particle distribution in the field of view, then select a representative part, observe and photograph it with the objective lens (×20), and analyze the total number of particles and the distribution ratio.

[0077] Table 3 Particle size determination results

[0078] 4. Content determination

[0079] The sulfachlorpyrifos sodium and methotrexate suspensions prepared using the methods of Examples 2, 4-6 and Example 11 were subjected to content determination, as detailed in Table 4.

[0080] Table 4. Content determination results

[0081] 5. Formulation stability studies

[0082] (1) Strong light irradiation test

[0083] After preparing the sulfachlorpyridazine sodium and methotrexate suspension according to the methods of Examples 2, 4-6 and Example 11, the samples were placed under strong light irradiation (4500 lx ± 500 lx) on the same day after the content was determined. Samples were taken at intervals on the 5th and 10th days to determine the content of sulfachlorpyridazine sodium and methotrexate. At the same time, the appearance, sedimentation volume ratio, redispersibility, and related substances of the preparation were observed.

[0084] Table 5 Results of the strong light irradiation test

[0085] (2) Accelerated stability test

[0086] After preparing the sulfachlorpyrifos sodium methotrexate suspension according to the methods of Examples 2, 4-6 and Example 11, accelerated stability tests were carried out in accordance with the requirements of the Guidelines for Stability Testing of Raw Materials and Preparations in the Pharmacopoeia of the People's Republic of China (2020 Edition) (Appendix 9001). The samples were placed at a temperature of 30℃±2℃ and 65%±5% for 6 months, and samples were taken at 1, 2, 3 and 6 months. The appearance, sedimentation volume ratio, redispersibility, related substances, content and other items were tested according to the key stability test items.

[0087] Table 6 Accelerated stability test results

[0088] The test results show that the sulfachlorpyridazine sodium methotrexate suspensions of Examples 2, 4-6 and 11 did not change in properties during the accelerated stability test period, the sedimentation ratios were all greater than 0.9, the content did not change significantly, and all indicators met the requirements, indicating that the sulfachlorpyridazine sodium methotrexate suspension prepared by the present invention has good stability.

[0089] The above examples show that when the amount of xanthan gum added is less than 0.1g, the viscosity and structure of the system are insufficient, and sedimentation cannot be suppressed; when the amount of xanthan gum added is more than 0.125g, the viscosity of the system is too high, and it is easy to coagulate into lumps at the bottom, which is not conducive to redispersibility; when the amount of Tween-80 added is less than 0.05g, the system is not sufficiently wetted, and particle agglomeration is likely to occur; when the amount of Tween-80 added is more than 0.1g, the wetting agent is excessive, which destroys the overall structure of the system and the redispersibility becomes poor. When the ratio of xanthan gum to Tween-80 is less than 2:1, the structure is not sufficiently differentiated, and the sedimentation rate is accelerated. When the ratio is greater than 2.5:1, the particles are not sufficiently wetted, and they are prone to forming compact precipitates, resulting in poor redispersibility. When the ratio is controlled at about 2.0:1 to 2.5:1, the resulting suspension can not only maintain a very high suspension state for a long time (30-day sedimentation volume ratio >0.99), but the sediment is also loose and can be completely redispersed with just a slight shaking. Its overall stability is significantly better than other ratio combinations.

[0090] Example 15: Pharmacokinetic Study of Sulfachlorpyrifos Sodium Methamide Suspension in Chickens

[0091] 1. Test Methods

[0092] (1) Test drug

[0093] Sulfachlorpyrimethanil sodium soluble powder (30%): batch number D20250403, manufacturer: Wuhan Huisheng Biotechnology Co., Ltd.

[0094] Methimidine raw material: batch number 20240815, content 98.6%, synthesized by the National Veterinary Drug Residue Reference Laboratory of Huazhong Agricultural University.

[0095] The sulfachlorpyrimethanine sodium and methotrexate suspension prepared in Example 5.

[0096] (2) Experimental animals

[0097] Seventy-two healthy broiler chickens weighing 1.6-2.0 kg, half male and half female, were randomly divided into six groups of 12 chickens each (half male and half female). The groups corresponded to low, medium, and high doses of sulfachlorpyridazine sodium methotrexate suspension, SPZ monotherapy group, ADP monotherapy group, and sulfachlorpyridazine sodium methotrexate intravenous injection group, respectively.

[0098] (3) Drug administration and sampling

[0099] Administration: Pharmacokinetic studies were conducted using a single-dose administration method. All test chickens were fasted for 12 hours before administration and resumed normal water intake 2 hours after administration. They were fed uniformly 4 hours later. The grouping and administration details of the animals are shown in Table 7.

[0100] Sampling: Blank plasma samples were collected before administration. For each oral administration group, 2-3 mL of blood was collected from the wing vein at 0.5, 1, 2, 3, 4, 5, 6, 8, 12, 24, 36, 48, 60, and 72 h after administration. For the intravenous injection group, 2-3 mL of blood was collected from the wing vein at 5 min, 0.5, 1, 2, 3, 4, 6, 8, 12, 24, 36, 48, 60, and 72 h after administration. The plasma was centrifuged at 2500 r / min for 10 min, and the supernatant plasma was collected and stored at -20℃.

[0101] Table 7 Grouping and Medication Use

[0102] 2. Test Results

[0103] 2.1 Plasma pharmacokinetic parameters of ADP in chickens

[0104] The results show (Table 8, ...) Figure 1 After oral administration, ADP levels in chickens (T) max The duration was 2.83–4.34 h, C max The effective concentrations ranged from 501 to 1228.67 ng / mL, with elimination half-lives of 11.22 to 14.32 h. No significant differences were observed among the dosage groups, indicating that ADP absorption in chickens is relatively slow. Its absolute bioavailability ranged from 63.52% to 81.39%, indicating that sulfachlorpyrifos sodium / methoprim suspension has good oral absorption characteristics in chickens. Combined with the long elimination half-life of ADP (>11 h), this compound preparation helps maintain effective blood drug concentrations for a longer period, providing sustained anticoccidial activity for clinical use.

[0105] Table 8. Pharmacokinetic parameters of ADP

[0106] 2.2 Plasma pharmacokinetic parameters of SPZ in chickens

[0107] The results show (Table 9, ...) Figure 2 After oral administration, SPZ levels in chickens were elevated by T. max The duration is 3.5~7.67 h, C maxThe effective concentrations ranged from 23.35 to 61.23 mg / mL, with elimination half-lives of 7.78 to 10.13 h and mean retention times of 12.12 to 15.29 h. Compared with the SPZ monotherapy group, the Tmax and mean retention time of SPZ were significantly prolonged in the medium and high dose groups of sulfachlorpyrifos sodium methotrexate suspension. This indicates that the combination of ADP and SPZ can slow down the absorption rate of SPZ and reduce its clearance process in vivo, thereby increasing the residence time of SPZ in chickens and prolonging the effective duration of action.

[0108] Table 9 Pharmacokinetic parameters of SPZ

[0109] In summary, the sulfachlorpyrifos sodium-methoprim suspension prepared according to Example 5 exhibits excellent pharmacokinetic properties in chickens, and has the following significant advantages compared to the similar drug trimethoprim (TMP): (1) ADP has a long half-life and a prolonged effective duration. The elimination half-life of ADP in chickens is 11.22–14.32 h, with no significant difference between the dosage groups, and is close to that of the intravenous injection group (13.44 h). Compared with the relatively short elimination half-life of the similar drug trimethoprim (TMP) in poultry (the literature reports that the half-life of TMP in chickens is about 2–4 h), the half-life of ADP is significantly prolonged, which is beneficial for maintaining a long-term effective blood drug concentration and reducing the frequency of administration.

[0110] (2) ADP and SPZ have a synergistic effect, prolonging the duration of action of SPZ in vivo. The T-cell activity of SPZ in the high-dose and medium-dose groups of sulfachlorpyridazine sodium methotrexate suspension... max The mean residence time (6.5–7.67 h) and mean retention time (15.16–15.29 h) were significantly longer than those of the SPZ monotherapy group (T0). max The half-life (MRT) of SPZ was 3.67 h and 12.81 h, indicating that ADP can delay the absorption and elimination of SPZ, allowing SPZ to remain in the chicken's body for a longer period. The elimination half-life of SPZ (7.78~10.13 h) was also maintained at a relatively long level, ensuring the sustained antiparasitic activity of the compound preparation.

[0111] In summary, sulfachlorpyrifos sodium methotrexate suspension exhibits pharmacokinetic advantages in chickens, including a long ADP half-life, high bioavailability, and a significantly prolonged SPZ retention time. Compared to TMP reported in the literature, ADP has a longer elimination half-life and superior oral absorption characteristics, providing a durable and highly effective anticoccidial drug combination for clinical use.

[0112] Example 16: Pharmacokinetic Study of Sulfachlorpyrifos Sodium Methamide Suspension in Sheep

[0113] 1. Test Methods

[0114] (1) Test drug

[0115] Sulfachlorpyrimethanil sodium soluble powder (30%): batch number D20250403, manufacturer: Wuhan Huisheng Biotechnology Co., Ltd.

[0116] Methimidine raw material: batch number 20240815, content 98.6%, synthesized by the National Veterinary Drug Residue Reference Laboratory of Huazhong Agricultural University.

[0117] The sulfachlorpyrimethanine sodium and methotrexate suspension prepared in Example 5.

[0118] (2) Experimental animals

[0119] Forty-eight Hu sheep aged 10-12 months, half male and half female, weighing 50±5 kg, were identified by ear tags and randomly divided into 6 groups (half male and half female) according to their weight. These groups corresponded to low, medium, and high doses of sulfachlorpyrifos sodium methotrexate suspension, ADP single drug group, SPZ single drug group, and SPZ-ADP intravenous injection group, respectively. During the experiment, the sheep were given a basal diet and normal drinking water.

[0120] (3) Drug administration and sampling

[0121] Administration: Pharmacokinetic studies were conducted using a single-dose administration method. All test sheep were fasted for 12 hours before administration and resumed normal water intake 2 hours after administration. They were fed uniformly 4 hours later. Animal grouping and administration details are shown in Table 10.

[0122] Sampling: Blank plasma samples were collected before drug administration. After drug administration, 3-4 mL blood samples were collected from the jugular vein at 0.25 h, 0.5 h, 1 h, 2 h, 3 h, 4 h, 6 h, 8 h, 12 h, 24 h, 48 h, 72 h, 96 h, 120 h, 144 h, and 168 h. The samples were centrifuged at 2500 r / min for 10 min, and the supernatant plasma was collected and stored at -20℃.

[0123] Table 10 Grouping and Medication Use

[0124] 2. Test Results

[0125] 2.1 Plasma pharmacokinetic parameters of ADP in sheep

[0126] The results show (Table 11, ...) Figure 3 Following oral administration, ADP levels in sheep were... max The duration is 6.3~10.8 h, C maxThe plasma concentrations ranged from 131.2 to 416.3 ng / mL, with an elimination half-life of 21.2 to 25.6 h. The plasma concentrations initially increased and then decreased over time, indicating relatively slow absorption in sheep. The apparent volume of distribution ranged from 12901.1 to 19570 mL / kg, which was relatively high, indicating sufficient tissue distribution. The clearance rate ranged from 433.1 to 543.3 mL / h / kg, with a mean retention time of 28.5 to 36.3 h, indicating a relatively long residence time of ADP in sheep. These results suggest that the main pharmacokinetic characteristics of ADP in sulfachlorpyrifos sodium methotrexate suspension in sheep are relatively slow absorption, wide distribution, and slow elimination.

[0127] Table 11 Pharmacokinetic parameters of ADP

[0128] 2.2 Plasma pharmacokinetic parameters of SPZ in sheep

[0129] The results show (Table 12, ...) Figure 4 Following oral administration, SPZ levels in sheep were measured by T. max For 6.0~7.5 h, C max The effective concentrations ranged from 14132.4 to 53029.9 ng / mL, with an elimination half-life of 8.2 to 9.3 h, indicating rapid absorption of the drug in sheep. The elimination half-life of the intravenous injection group (10.1 ± 0.6 h) was similar to that of the oral administration group. Compared with the SPZ monotherapy group, the absolute bioavailability of SPZ in the sulfachlorpyrifos sodium methotrexate suspension was 79.5% to 81.4%, which was higher than that of the monotherapy group (68.1%), indicating that the combination of ADP and SPZ significantly improved the oral bioavailability of the formulation.

[0130] Table 12 Pharmacokinetic parameters of SPZ

[0131] In summary, the sulfachlorpyrifos sodium-methoprim suspension prepared according to Example 5 exhibits excellent pharmacokinetic properties in sheep, and has the following significant advantages compared to the similar drug trimethoprim (TMP): (1) The half-life is significantly prolonged, resulting in a longer effective duration. The elimination half-life of ADP in sheep is as long as 21.2–25.6 h, while the half-life of TMP in sheep after intravenous injection, as reported in the literature, is only 0.77 h (Iqbal et al., 2010). The half-life of ADP is about 30 times that of TMP. Even in buffalo calves, the half-life of ADP (6.14 h) is about twice that of TMP (3.08 h) (Iqbal et al., 1994). At the same time, the average residence time of ADP (28.5–36.3 h) is relatively long, indicating that its in vivo action time is significantly better than that of TMP, and it can achieve a more prolonged antiparasitic effect.

[0132] (2) Significantly improved oral bioavailability. The absolute bioavailability of SPZ in the compound preparation reached 79.5%~81.4%, which was higher than that of the SPZ monotherapy group (68.1%), indicating that the combination of ADP and SPZ can significantly improve the oral absorption efficiency of SPZ. This synergistic effect helps to enhance clinical efficacy and reduce drug dosage and cost.

[0133] (3) Wide distribution in tissues. The apparent volume of distribution of ADP is as high as 12901.1~19570 mL / kg, which is much higher than the total body fluid volume, indicating that the drug is widely distributed in tissues.

[0134] (4) Stable blood drug concentrations and well-matched absorption and elimination patterns. ADP absorption is relatively slow (Tmax 6.3~10.8 h), but elimination is also slow, resulting in a gradual increase followed by a decrease in blood drug concentration, avoiding peak-to-trough fluctuations. Combined with the faster absorption of SPZ (Tmax 6.3~10.8 h), the blood drug concentration exhibits a stable blood drug concentration. max 6.0~7.5 h, C max With concentrations ranging from 14132.4 to 53029.9 ng / mL, compound preparations can achieve both rapid and long-lasting effects, resulting in a synergistic effect of rapid onset and sustained action.

[0135] In summary, sulfachlorpyridazine sodium and methotrexate suspension exhibits outstanding pharmacokinetic characteristics in sheep, including a long half-life, high bioavailability, wide tissue distribution, and prolonged effective duration. Its overall performance is significantly superior to that of sulfachlorpyridazine sodium monotherapy or SPZ-TMP compound preparation.

[0136] Example 17: Application of sulfachlorpyrifos sodium and methotrexate suspension in chicken Eimeria tenella infection

[0137] 1. Test Methods

[0138] (1) Test drug

[0139] Control drug 1: Sulfachlorpyrifos sodium soluble powder (30%): batch number D20250403, manufacturer: Wuhan Huisheng Biotechnology Co., Ltd.

[0140] Control drug 2: Sulfachlorpyrifos sodium and trimethoprim soluble powder: (100g: 20g sulfachlorpyrifos sodium + 4g trimethoprim), batch number 24090102, Henan Muxiang Biotechnology Co., Ltd.

[0141] Control drug 3: Sulfachlorpyridazine sodium and dimethoprim suspension (200ml: 20g sulfachlorpyridazine sodium + 8g dimethoprim): Batch number 250606007, manufacturer: China Animal Husbandry Industry Co., Ltd. (Nanjing) Animal Pharmaceutical Co., Ltd.

[0142] Test drug: Sulfachlorpyrimethanine sodium and methotrexate suspension prepared in Example 5.

[0143] (2) Test insect strains

[0144] Eimeria tenella ( Eimeria tenella (This was a gift from Professor Su Xun of China Agricultural University.)

[0145] (3) Experimental animals

[0146] 14-day-old white-feathered broiler chickens free from coccidiosis infection are identified by foot tags.

[0147] (4) Trial grouping and administration

[0148] Chicks aged 1 day to 14 days were weighed and selected from those with similar weights (weight difference not exceeding 10 g) and confirmed to be healthy by prior clinical observation and free of coccidiosis in fecal examination. They were then randomly divided into 11 groups: a negative control group (no medication), a test drug group, a control drug group, and a blank control group. Each group consisted of 30 chicks, clearly marked (recorded as day 1 of the experiment, D0). Except for the healthy control group, each chick in the other groups was orally infected with 5 × 10⁵ ppm of the test drug. 4 Eimeria sporulated oocysts were used to construct a coccidiosis model in chicks. When chicks exhibited typical clinical symptoms of coccidiosis, such as poor mental state, standing listlessly with closed eyes, diarrhea, and bloody feces, and oocysts were found in fecal examination, the coccidiosis infection was considered successful. Treatment was then initiated, with dosages and groupings as shown in Table 13: once daily for 3–5 days. The control group and negative control group received equal volumes of drinking water.

[0149] Table 13 Animal grouping and administration information

[0150] (5) Experimental observation and data collection

[0151] During the experiment, the clinical symptoms and morbidity of the chickens were observed daily, and their drinking water, feed intake, mental state, plumage color, fecal condition, and necropsy results of chickens that died from coccidiosis were recorded. Weight data, intestinal samples, and pathological indicators were collected from each group of chickens at 14 days and 23 days of age. Fecal samples were collected from days 4 to 10 after coccidiosis infection (i.e., 18 to 24 days of age), and data on coccidia oocyst excretion were collected from each group.

[0152] (6) Criteria for evaluating therapeutic efficacy

[0153] Based on the relative weight gain, survival rate, lesion value, and oocyst value of each experimental chicken, the anticoccidial index (ACI) was calculated according to the formula of Merck & Co., Ltd.

[0154] ACI = (Relative weight gain rate + Survival rate) - (Disease value + Oocyte value).

[0155] (7) Determination of overall drug efficacy

[0156] Referring to the method of Suo et al. (1997), under the condition that all indicators of the control group chickens are normal, the effect of drug treatment or prevention on the drug test group is judged according to the following criteria (Table 14) based on the ACI.

[0157] Table 14 Efficacy Assessment

[0158] 2. Test Results

[0159] (1) Anticoccidial Comprehensive Index

[0160] The Anticoccidial Comprehensive Index (ACI) was calculated using the formula: ACI = (relative weight gain + survival rate) - (lesion value + oocyst value). The ACI values ​​for each group of chickens were calculated. Results showed that the ACI values ​​of all dose groups of the tested drug were superior to the control drug group. Specifically, the high-dose 5-day group had an ACI of 186.08, significantly exceeding the high-efficiency anticoccidial standard (ACI > 180), and was superior to the high-dose 3-day group (177.86), indicating that prolonged administration could further enhance the therapeutic effect. The medium-dose 3-day and 5-day groups had ACIs of 181.10 and 180.13, respectively, also achieving a high-efficiency anticoccidial effect. The low-dose group had an ACI of 163.31–175.88, showing a moderate effect and a clear dose-response relationship.

[0161] Compared with the control group, the high-dose group of the test drug showed significantly lower oocyst and lesion counts, significantly better relative weight gain than the SPZ monotherapy group, and a 100% survival rate. These results indicate that sulfachlorpyrifos sodium-methamphetamine suspension is more effective against coccidiosis than conventional sulfonamides and their compound preparations, providing a new and highly efficient alternative for the prevention and control of coccidiosis in chickens.

[0162] Table 15 Anticoccidial Index (ACI) of the Experimental Groups

[0163] (2) Determination of drug efficacy

[0164] According to the comprehensive efficacy evaluation criteria (ACI value 0-120 is ineffective, 121-160 is ineffective, 161-180 is moderately effective, and >180 is highly effective), sulfachlorpyridazine sodium and methotrexate suspension is more effective than sulfachlorpyridazine sodium soluble powder, sulfachlorpyridazine sodium and trimethoprim soluble powder, and sulfachlorpyridazine sodium and dimethoprim suspension in treating Eimeria tenella infection in chickens.

[0165] In summary, the sulfachlorpyrimethanine sodium methotrexate suspension prepared according to Example 5 achieved excellent results in terms of quality control and clinical efficacy.

[0166] Example 18: Application of sulfachlorpyrifos sodium and methotrexate suspension in coccidiosis infection in sheep

[0167] 1. Test Methods

[0168] (1) Test drug

[0169] Reference drug: Sulfachlorpyrifos sodium soluble powder (30%): batch number D20250403, manufacturer: Wuhan Huisheng Biotechnology Co., Ltd.

[0170] Test drug: Sulfachlorpyrimethanine sodium and methotrexate suspension prepared in Example 5.

[0171] (2) Experimental animals

[0172] Lambs aged 45-55 days, weighing approximately 15-20 kg, are naturally infected with coccidia, with an oocyst excretion (OPG) of 10,000-20,000. They are fed a diet free of anticoccidial drugs and antibiotics.

[0173] (4) Trial grouping and administration

[0174] Clinical symptoms and fecal characteristics were observed in the experimental lambs. Fecal samples were collected for coccidia oocyst levels and coccidia species identification. Based on the coccidia oocyst levels in the feces (OPG range of 10,000-20,000, weight approximately 15 kg), the lambs were randomly divided into three groups of 10 lambs each: a negative control group (infected but not treated, NC), a sulfachlorpyridazine sodium soluble powder group (SPZ), and a sulfachlorpyridazine sodium methotrexate suspension group (SPZ-ADP). Except for the NC group, the other groups were administered the medication by gavage according to the recommended dosage or the experimental dosage, for 5 consecutive days. Details of the experimental grouping and administration regimens are shown in Table 16. During the experiment, the lambs were fed daily according to standard sheep farm practices, and they had free access to feed.

[0175] Table 16 Animal Grouping and Drug Use

[0176] (5) Experimental observation and data collection

[0177] During the experiment, the clinical manifestations of sheep in each group were observed daily, including their mental state, defecation status, water intake, feed consumption, morbidity, and mortality. If sheep died, the number of dead sheep in each group was recorded, and necropsy and parasite identification were performed to determine the cause of death.

[0178] (6) Criteria for evaluating therapeutic efficacy

[0179] 1) Number of coccidia oocysts and rate of reduction of coccidia oocysts

[0180] The number of coccidia oocysts (OPG) in the feces of each lamb in the three experimental groups was measured on days D0, D1-D7, D14, and D21. The average OPG of lambs in each group was calculated, and the relative reduction rate of coccidia oocysts in the drug group was calculated based on the average OPG on day D0.

[0181] OPG reduction rate (%) = [(average OPG before administration - average OPG after administration) / average OPG before administration] × 100

[0182] 2) Weight gain rate and relative weight gain rate

[0183] The weight of lambs in each group was measured on D0 and D21. Using the weight on D0 as the base, the weight gain rate of each lamb during the period from D0 to D21 was calculated, and the average weight gain rate and relative weight gain rate of each group of lambs were further calculated.

[0184] Weight gain rate (%) = [(D21 weight - D0 weight)] / D0 weight × 100

[0185] Relative weight gain rate (%) = (Average weight gain in the drug group / Average weight gain in the negative control group) × 100

[0186] 2. Test Results

[0187] (1) Coccidia oocyst markers

[0188] After administration, coccidia oocysts in sheep feces were counted on days D0, D1-D7, D14, and D21. The results are shown in Table 17.

[0189] Table 17 Oocyte expulsion status in each experimental group

[0190] Note: Data are presented as mean ± standard deviation. The superscript letters "a, b, c" are used to indicate differences between groups. Data with different letters indicate significant differences (p≤0.05), while data with the same letter indicate no significant differences (p>0.05).

[0191] (2) Coccidia oocyst reduction rate

[0192] The reduction rate of coccidia oocysts in each experimental group was calculated, and the results are shown in Table 18.

[0193] Table 18 Reduction rate of coccidia oocysts in each experimental group

[0194] (3) Body weight indicators

[0195] Table 19 Weight gain of sheep in each experimental group

[0196] Note: Data are presented as mean ± standard deviation. The superscript letters "a, b, c" are used to indicate differences between groups. Data with different letters indicate significant differences (p≤0.05), while data with the same letter indicate no significant differences (p>0.05).

[0197] The experimental results showed that, compared with the negative control group, the sulfachlorpyridazine sodium and methotrexate suspension of this invention significantly reduced the amount of coccidia oocysts excreted in feces in a naturally infected lamb coccidiosis model. The oocyst reduction rate reached over 95% 3–7 days after administration, and the oocysts were completely cleared by day 6. Furthermore, the oocyst reduction rates remained as high as 91.38% and 83.48% on days 14 and 21 after administration, respectively, while the SPZ monotherapy group showed no significant inhibitory effect at the same time. Simultaneously, the sulfachlorpyridazine sodium and methotrexate suspension of this invention significantly promoted the weight gain of infected lambs, with a relative weight gain rate as high as 173.68%, significantly better than the SPZ monotherapy group (121.88%), demonstrating a good growth-promoting effect. In summary, the sulfachlorpyridazine sodium and methotrexate suspension prepared according to Example 5 achieved excellent results in terms of quality control and clinical efficacy.

Claims

1. A sulfachlorpyrimethanine sodium-methoprim suspension, characterized in that, Each 100ml suspension consists of the following components: 20-50g sodium sulfachlorpyrifos, 4-10g methotrexate, 0.1-0.125g suspending agent, 0.05-0.1g wetting agent, 0.2-0.5g antioxidant, 0.1-0.25g metal chelating agent, and solvent to a final volume of 100ml; The metal chelating agent is disodium edetate; The solvent is purified water; The antioxidant is one of anhydrous sodium sulfite and sodium thiosulfate; The particle size of the methomyl is ≤15μm; The suspending agent is xanthan gum, and the wetting agent is Tween-80, with a weight ratio of 2.0:1 to 2.5:

1.

2. The sulfachlorpyrifos sodium-methoprim suspension according to claim 1, characterized in that, Each 100ml suspension consists of the following components: 20-40g sodium sulfachlorpyridazine, 4-8g methotrexate, 0.1-0.125g suspending agent, 0.05-0.1g wetting agent, 0.2-0.5g antioxidant, 0.1-0.25g metal chelating agent, and solvent to a final volume of 100ml.

3. The sulfachlorpyrimethanine sodium-methoxybenzyl phosphate suspension according to claim 1, characterized in that, Each 100ml suspension consists of the following components: 20g sodium sulfachlorpyrifos, 4g methotrexate, 0.1-0.125g suspending agent, 0.05-0.1g wetting agent, 0.2g antioxidant, 0.1g metal chelating agent, and solvent to a final volume of 100ml.

4. The method for preparing the sulfachlorpyrifos sodium-methoxybenzyl phosphate suspension according to any one of claims 1 to 3, characterized in that, The steps are as follows: ① Weigh the prescribed amount of purified water, stir continuously at 500 rpm, heat to 40°C and keep warm; ② Add the suspending agent to the purified water and stir continuously for 1 hour until it is completely dissolved; ③ Add wetting agent, antioxidant, and metal chelating agent, and stir for 10 minutes to dissolve completely; ④ Add methotrexate with a particle size ≤15μm and stir for 10min; ⑤ Add sodium sulfachlorpyrifos and stir for 10 minutes; ⑥ After bringing the above system to a constant volume, set the speed of the emulsifying homogenizer shearing machine to 4000 rpm and the shearing time to 30 min.

5. The use of the sulfachlorpyrifos sodium methotrexate suspension according to any one of claims 1 to 3 in the preparation of anticoccidial drugs for livestock and poultry.

6. The application according to claim 5, characterized in that, The suspension is administered orally.

7. The application according to claim 6, characterized in that, The suspension can improve the weight gain rate of coccidia-infected livestock and poultry, reduce intestinal lesion values, quickly clear oocysts, and maintain a long-lasting anticoccidia protective effect after drug withdrawal.

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