Cefalonium injection and its preparation process

Abstract

The application discloses a ceftriaxone injection and a preparation process thereof, and belongs to the technical field of veterinary medicine preparation. The ceftriaxone injection comprises the following components: ceftriaxone, hydrogenated castor oil, poloxamer, polyethylene glycol, sesame oil and glyceryl caprylate / caprate. The ceftriaxone injection has rapid effectiveness and super long effectiveness, and has stable product quality. The problem of rapid effectiveness and long effectiveness is solved successfully; the rapid effectiveness and long effectiveness characteristics of the preparation are balanced; and when used, the ceftriaxone injection is easy to extract and easy to inject, has small irritation to an injection site and has high bioavailability, so that the compliance and treatment effect of animals are improved obviously, the number of drug administration is reduced due to the unique rapid and long effectiveness characteristics, and the treatment cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of veterinary drug formulation technology, specifically relating to a ceftiofur injection and its formulation process. Background Technology

[0002] Ceftiofur is a third-generation cephalosporin antibiotic used in veterinary clinical practice. It has broad-spectrum and highly effective bactericidal activity, with strong killing effects on Gram-positive and Gram-negative bacteria, including β-lactam-producing fungal strains. Its mechanism of action is to block cell wall synthesis by acting on bacterial transpeptidase, thus exhibiting bactericidal activity. It is used to treat and control bacterial intestinal and respiratory infections in livestock, and has good therapeutic effects on common clinical livestock and poultry diseases such as swine pneumonia, swine actinobacillus pleuropneumonia, swine streptococcal disease, and piglet yellow and white scours.

[0003] However, the unstable chemical properties of its molecular structure in aqueous environments pose a continuous technical challenge to the development of long-acting, safe, and easy-to-use injectable formulations. To overcome this challenge, existing technologies have explored several pathways, including oily suspensions, non-aqueous solutions, and other advanced delivery systems, but each has revealed technical bottlenecks that are difficult to address collaboratively.

[0004] To avoid drug degradation in water, the most common and mature technical approach is to prepare an oily suspension from chemically stable ceftiofur salts (such as hydrochloride) or ceftiofur crystals (free acid). For example, Chinese patent CN101401787A discloses a long-acting ceftiofur injection and its preparation method, which is a long-acting formulation that uses an oil ester and a suspending agent to form a gel system to disperse ceftiofur micropowder.

[0005] As subsequent research and development continues, to further improve the long-acting effect and physical stability, existing technologies, such as Chinese patent CN105232458A, disclose a ceftiofur crystal suspension injection and its preparation method. Its formulation is characterized by the addition of povidone and polyethylene glycol as key injection adjuvants to an oily carrier primarily composed of soybean oil. The preparation method involves adding PVP and polyethylene glycol to the oil, then adding an antibacterial agent, sterilizing, adding ceftiofur crystals, and finally processing through high-speed shearing and colloid milling. In the aforementioned existing technical solutions, the main technical contribution of polyethylene glycol is described as increasing the solvent's carrying capacity and improving suspension adhesion, i.e., acting as a suspending agent and dispersant to improve the physical stability of the formulation. Furthermore, according to the pharmacokinetic data of this patent, the product is still a typical long-acting sustained-release formulation, and its formulation strategy essentially maintains the suspension stability of the system by adding high molecular weight polymers.

[0006] Existing technologies, such as Chinese patent CN102813623A, disclose a method for preparing ceftiofur hydrochloride suspension injection, which uses a more refined two-step grinding process to strictly control drug particle size and improve stability. Although these existing technologies have achieved significant results in terms of chemical stability and long-lasting sustained release, they still have the following problems: drug particles inevitably settle and aggregate during storage due to gravity, sometimes even forming hard clumps that are difficult to redisperse; therefore, they must be vigorously shaken before use, and even then, it is difficult to guarantee that the dosage drawn each time is accurate and uniform. Furthermore, to slow down sedimentation, the above formulations usually rely on high-viscosity oily carriers or high-concentration suspending agents. This directly leads to difficulties in extraction and poor needle penetration during use, and easily causes local irritation reactions such as pain and swelling at the injection site, reducing animal compliance. More importantly, the above technical solutions rely on the slow dissolution and release mechanism of the drug from solid particles, resulting in a long onset time and a slow peak blood concentration, making it difficult to quickly control acute or severe infections and failing to meet practical needs.

[0007] Existing technologies, such as Chinese patent CN101953889A which discloses a compound ceftiofur suspension emulsion injection and its preparation method, and Chinese patent CN101780088A which discloses a compound ceftiofur hydrochloride injection, involve dissolving ceftiofur hydrochloride in a specific solvent to form a clear, homogeneous solution. One of these technologies uses approximately 80% water for injection, while ceftiofur aqueous solution is unstable and can only be stored for 12 hours at 15-30°C. Another uses a combination of polyethylene glycol and anhydrous ethanol. The essence of these solutions is to completely dissolve the drug, forming a true solution dispersed at the molecular level. According to the basic principles of pharmacokinetics, once the drug is injected into the body in a dissolved state, it will inevitably be rapidly absorbed and eliminated, exhibiting typical rapid-acting and short-acting characteristics. While these technologies solve some stability issues, they completely sacrifice long-term efficacy, requiring frequent injections in actual use.

[0008] In summary, existing technologies in the development of ceftiofur injection present a contradiction in pharmacokinetics between rapid onset and long-lasting effect, as well as a conflict between low viscosity and ease of use and anti-settling stability in physicochemical aspects. Existing technologies can only make trade-offs among these contradictions and have failed to provide a solution that can achieve both rapid onset and long-lasting effect, while also possessing high physical stability and low viscosity for ease of use.

[0009] Therefore, the technical problem we want to solve is to develop a stable, safe, and fast-acting ceftiofur injection and its formulation process. Summary of the Invention

[0010] The first objective of this invention is to provide a ceftiofur injection formulation that combines rapid and long-lasting effects, high stability, and compliance with standards.

[0011] The second objective of this invention is to provide a formulation process for the above-mentioned ceftiofur injection that combines rapid and long-lasting effects, high stability, and compliance with standards.

[0012] To solve the above-mentioned technical problems, the present invention discloses a ceftiofur injection containing the following components: ceftiofur, hydrogenated castor oil, poloxamer, polyethylene glycol, sesame oil, and caprylic / capric glyceride.

[0013] In some embodiments of the present invention, each 100g injection solution comprises: 10g ceftiofur, 0.6g hydrogenated castor oil, 0.4g poloxamer, 28-36g polyethylene glycol, 22-30g sesame oil, and the balance being caprylic / capric glyceride.

[0014] In some embodiments of the present invention, the molecular weight of the polyethylene glycol is 600-1000.

[0015] In some specific embodiments of the present invention, each 100g of the injection solution is composed of the following components: 10g of ceftiofur, 0.6g of hydrogenated castor oil, 0.4g of poloxamer, 30g of polyethylene glycol, 22g of sesame oil, and the balance being polyethylene glycol.

[0016] In some specific embodiments of the present invention, each 100g of the injection solution is composed of the following components: 10g of ceftiofur, 0.6g of hydrogenated castor oil, 0.4g of poloxamer, 28g of polyethylene glycol, and 28g of sesame oil.

[0017] In some specific embodiments of the present invention, each 100g of the injection solution is composed of the following components: 10g of ceftiofur, 0.6g of hydrogenated castor oil, 0.4g of poloxamer, 36g of polyethylene glycol, and 25g of sesame oil.

[0018] In some specific embodiments of the present invention, each 100g of the injection solution is composed of the following components: 10g of ceftiofur, 0.6g of hydrogenated castor oil, 0.4g of poloxamer, 33g of polyethylene glycol, and 30g of sesame oil.

[0019] In some preferred embodiments, the molecular weight of the polyethylene glycol is polyethylene glycol-600.

[0020] In some preferred embodiments, the molecular weight of the polyethylene glycol is polyethylene glycol-800.

[0021] In some preferred embodiments, the molecular weight of the polyethylene glycol is polyethylene glycol-1000.

[0022] In some preferred embodiments, the poloxamer is specifically poloxamer 188.

[0023] This invention also provides a formulation process for ceftiofur injection, comprising the following steps:

[0024] Step A: Add the total amount of sesame oil and caprylic / capric triglycerides to a clean oil phase preparation tank and mix thoroughly; heat to 160-170℃ and sterilize by dry heat for 2 hours. After sterilization, cool the mixed oil to 120℃ under sterile compressed air or nitrogen protection; while stirring, add the prescribed amount of hydrogenated castor oil and maintain the temperature at 120℃ for 5-10 minutes; then, while stirring slowly, cool to room temperature for later use.

[0025] Step B: In a sterile preparation tank, add the prescribed amount of polyethylene glycol, heat to 40-50°C, add the prescribed amount of poloxamer, and stir until completely dissolved; while continuously stirring, add the sterile ceftiofur raw material treated according to the requirements of the Veterinary Pharmacopoeia in batches and slowly to the above solution through a sterile feeding system, and continue stirring for 30 minutes to form an initial dispersion.

[0026] Step C: Transfer all the matrix prepared in step A to the sterile preparation tank in step B, turn on the high-shear disperser, and shear for 15-20 minutes to allow the oil phase, polyethylene glycol and drug particles to be initially mixed evenly, forming a milky white coarse suspension.

[0027] Step D: Homogenize the crude suspension obtained in step C by circulating it through a pre-sterilized high-pressure homogenizer. Set the homogenization pressure to 800-1000 bar and cycle 5-8 times. After homogenization, under nitrogen protection, dispense the ceftiofur injection into sterilized vials, and then stopper and cap them.

[0028] In some preferred embodiments, the formulation process specifically includes:

[0029] Step A: Add the total amount of sesame oil and caprylic / capric triglycerides to a clean oil phase preparation tank and mix thoroughly; heat to 160-170℃ and sterilize by dry heat for 2 hours. After sterilization, cool the mixed oil to 120℃ under sterile compressed air or nitrogen protection; while stirring, add the prescribed amount of hydrogenated castor oil and maintain the temperature at 120℃ for 5-10 minutes; then, while stirring slowly and controlling the cooling rate, start the programmed cooling program to cool to room temperature (25℃) at a rate of 1℃ / min.

[0030] Step B: In a sterile preparation tank, add the prescribed amount of polyethylene glycol, heat to 40-50°C, add the prescribed amount of poloxamer, and stir until completely dissolved; while continuously stirring, add the sterile ceftiofur raw material treated according to the requirements of the Veterinary Pharmacopoeia in batches and slowly to the above solution through a sterile feeding system, and continue stirring for 30 minutes to form an initial dispersion.

[0031] Step C: Transfer all the matrix prepared in step A to the sterile preparation tank in step B, turn on the high-shear disperser, and shear for 15-20 minutes to allow the oil phase, polyethylene glycol and drug particles to be initially mixed evenly, forming a milky white coarse suspension.

[0032] Step D: Homogenize the crude suspension obtained in step C using a pre-sterilized high-pressure homogenizer. Set the homogenization pressure and cycle 5-8 times. After homogenization, dispense the ceftiofur injection into sterilized vials under nitrogen protection, and then cap and seal them.

[0033] In some preferred embodiments, the cooling rate of the formulation process step A can be controlled by a programmed cooling program, which controls the cooling rate to 0.2°C / min to room temperature (25°C).

[0034] In some preferred embodiments, the cooling rate of the formulation process step A can be controlled by a programmed cooling program, which controls the cooling rate to 0.5°C / min to room temperature (25°C).

[0035] In some preferred embodiments, the homogenization pressure of the formulation process step D is 800-1000 bar.

[0036] The beneficial effects of this invention are as follows:

[0037] 1. This invention, through the construction of a unique composite system, synergistically achieves both rapid and long-lasting drug release. The formulation of this application, after injection, can quickly reach an effective blood drug concentration to control acute infection, and also provides a sustained therapeutic effect through the slow dissolution of drug particles. Pharmacokinetic data show that the C0.05 of the injection solution of this invention... max Both AUC and t were significantly higher than those of traditional long-acting formulations, while t 1 / 2 (K e It is far superior to fast-acting solutions, successfully solving the problem of combining fast-acting and long-acting properties; it achieves a balance between the fast-acting and long-acting characteristics of the formulation; and when used, it is easy to extract and inject, with little irritation to the injection site and high bioavailability. It not only significantly improves animal compliance and treatment effect, but also reduces the number of administrations and lowers treatment costs due to its unique fast-acting and long-acting characteristics.

[0038] 2. The ceftiofur injection of the present invention, through the formulation process of this application, can greatly improve the stability of the injection. This formulation process ensures that even after long-term storage and transportation, its pharmacokinetic characteristics remain highly consistent with the initial state, thereby solving the balance between the formulation and the stability of the final therapeutic effect. Attached Figure Description

[0039] Figure 1The image shows the high-performance liquid chromatogram of the sample prepared in Example 3. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the embodiments, but this is not intended to limit the present invention. Any equivalent substitutions made in the art based on the disclosure of the present invention shall fall within the protection scope of the present invention.

[0041] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0042] In this application, the terms “comprising,” “including,” and “containing,” and their equivalents, shall be understood in an open, non-exclusive sense, meaning “including but not limited to,” implying that in addition to the listed elements, components, and steps, other unspecified elements, components, and steps may also be covered. In this document, unless the context clearly specifies otherwise, singular terms shall cover plural references, and vice versa.

[0043] In this application, the excipients or reagents used in the injection solution may be sourced from commercial sources.

[0044] Example 1

[0045] A formulation process for ceftiofur injection: The sample of Example 1 was prepared according to the prescription dosage shown in Table 1 below. The specific formulation process was carried out by the following method, including step A: The total amount of sesame oil and caprylic / capric glyceride in the prescription was added to a clean oil phase preparation tank and mixed thoroughly. The mixture was heated to 160-170℃ and sterilized by dry heat for 2 hours. After sterilization, the mixed oil was cooled to 120℃ under sterile compressed air or nitrogen protection. While stirring, the prescribed amount of hydrogenated castor oil was added, and the mixture was stirred at 120℃ for 5-10 minutes. Subsequently, it was cooled to room temperature with slow stirring for later use.

[0046] Step B: In a sterile preparation tank, add the prescribed amount of polyethylene glycol, heat to 40-50°C, add the prescribed amount of poloxamer, and stir until completely dissolved; while continuously stirring, add the sterile ceftiofur raw material treated according to the requirements of the Veterinary Pharmacopoeia to the above solution in batches and slowly through a sterile feeding system, and continue stirring for 30 minutes to form an initial dispersion;

[0047] Step C: Transfer all the matrix prepared in step A to the sterile preparation tank in step B, turn on the high-shear disperser, and shear for 15-20 minutes to allow the oil phase, polyethylene glycol and drug particles to be initially mixed evenly, forming a milky white coarse suspension.

[0048] Step D: Homogenize the crude suspension obtained in step C by circulating it through a pre-sterilized high-pressure homogenizer. Set the homogenization pressure to 800-1000 bar and cycle 5-8 times. After homogenization, under nitrogen protection, dispense the ceftiofur injection into sterilized vials, and then stopper and cap them.

[0049] Examples 2, 3, and 4 were prepared according to the component formulation in Table 1. The specific preparation method was the same as in Example 1, and the specific poloxamer used was poloxamer 188. The difference was that the amount of the specific components was adjusted accordingly based on the component formulation data in Table 1.

[0050] Table 1

[0051]

[0052] To determine the pharmacokinetic parameters of the injection solution described in this invention, the following standardized method was used:

[0053] 1. Experimental design: Healthy pigs were selected as experimental animals and divided into groups corresponding to different formulations of the injection solution; each pig was given a single intramuscular injection at an equivalent dose of 5 mg / kg ceftiofur.

[0054] 2. Test Methods

[0055] 2.1 Dosing regimen and sample collection

[0056] At predetermined time points following drug administration (0.17, 0.5, 1, 2, 4, 8, 12, 24, 48, 72, 96, 120, 144, and 168 hours), 2-3 mL of whole blood was collected from the jugular vein of each experimental pig and placed in an anticoagulant tube. The collected blood samples were centrifuged at 4000 rpm for 10 minutes, and the supernatant plasma was separated and frozen at -20°C for later analysis.

[0057] 2.2 Plasma Sample Pretreatment

[0058] Since ceftiofur is rapidly metabolized in animals to the active metabolite desfuryl ceftiofur (DFC), this study calculated the blood concentration of ceftiofur by detecting the concentration of DFC.

[0059] 2.2.1 Drug Extraction

[0060] Thaw the frozen plasma sample naturally and shake well. Accurately pipette 500µL of plasma sample into a centrifuge tube, add 7mL LTE-borate (0.4%) buffer, and vortex thoroughly. Incubate the mixture in a 50°C water bath for 15 minutes, vortexing for 10 seconds every 3 minutes during this period. After the water bath, remove the sample, cool it to room temperature, centrifuge, and collect the supernatant for later use.

[0061] 2.2.2 Drug purification

[0062] Purification was performed using a solid-phase extraction (SPE) column (60 mg / 3 cc). First, the column was activated with 3 mL of methanol, then rinsed and equilibrated with ultrapure water. The prepared supernatant was added to the column, and the flow rate was adjusted to allow for slow passage; the eluent was discarded. Next, the column was rinsed with 6 mL of ultrapure water, and the eluent was discarded after slow passage. Finally, elution was performed with 6 mL of methanol, and all eluent was collected.

[0063] The collected eluent was purged with nitrogen to below 0.02 mL in a 40°C water bath, and then redissolved in 500 µL of 0.01 M ammonium acetate aqueous solution. After vortexing for 5 min and sonication for 5 min, the solution was filtered through a 0.22 µm nylon membrane filter, and the filtrate was collected for analysis.

[0064] 2.3 HPLC Detection Method

[0065] 2.3.1 Chromatographic conditions

[0066] Column: ZORBAX Eclipse XDB-C18 (4.6 × 150 mm, 5 µm)

[0067] Detection wavelength: 266 nm (DAD detector)

[0068] Column temperature: 30℃

[0069] Flow rate: 0.8 mL / min

[0070] Injection volume: 50µL

[0071] Mobile phase: Phase A is acetonitrile, and Phase B is a 0.1% trifluoroacetic acid aqueous solution;

[0072] Gradient elution procedure:

[0073]

[0074] 2.3.2 Establishment of Standard Curve

[0075] Blank plasma was collected and mixed with defuranoyl ceftiofur standard working solution to prepare a series of standards with concentrations of 0.25, 1.0, 2.5, 5.0, 10.0, 25.0, and 50.0 µg / mL. After processing according to the method described in Section 2.2, HPLC analysis was performed. A linear regression equation was established with the standard concentration as the abscissa (x) and the measured peak area as the ordinate (y).

[0076] 2.4 Data Processing and Calculation of Pharmacokinetic Parameters

[0077] Plasma samples collected at each time point were processed and tested using the method described above, and the concentration of DFC in the plasma was calculated based on the peak area and linear regression equation.

[0078] PKS pharmacokinetic analysis software was used to perform fitting analysis on blood drug concentration-time data. Based on the analysis results, the pharmacokinetic processes of both the test drug and the control drug in pigs conformed to a first-order absorption two-compartment open model. The following key pharmacokinetic parameters were calculated and obtained: absorption half-life (t... 1 / 2 (K a Elimination half-life (t) 1 / 2 (K e Peak time (tpeak), peak concentration (C) max The area under the blood drug concentration curve (AUC) and plasma clearance rate (CL / f(s)) were also considered.

[0079] The t 1 / 2 (K a ),t 1 / 2 (K e The unit of tpeak is h; the C max The unit is μg / mL; the unit of AUC is μg·h / mL; the unit of CL / f(s) is mg / mL / h / (μg / mL).

[0080] The high-performance liquid chromatogram of the sample prepared in Example 3 is shown below. Figure 1 As shown.

[0081] The pharmacokinetic tests of Examples 1-4 are shown in Table 2;

[0082] Table 2

[0083]

[0084] As shown in Table 2, the formulations of Examples 1 to 4 all fall within the solvent ratio range defined by this invention. Pharmacokinetic data show that these examples all exhibit excellent and highly similar performance characteristics, successfully overcoming the problem of the incompatibility between rapid and long-lasting effects in existing technical approaches; in particular, Example 3 demonstrates a particularly outstanding balance in various pharmacokinetic aspects, reflecting the optimal technical effect within the scope of this invention.

[0085] Comparative Example 1

[0086] Commercially available formula, product name: EasySpeed; batch number: 706894.

[0087] Comparative Example 2

[0088] Comparative Example 2 was prepared according to the formulation and method of Example 1 in CN105232458A.

[0089] Comparative Example 3

[0090] Comparative Example 3 was prepared according to the formulation and method of Example 1 in CN107049943A.

[0091] The pharmacokinetic parameters of Comparative Examples 1-3 are shown in Table 3 below:

[0092] Table 3

[0093]

[0094] Comparative Example 1 is a commercially available product widely used in this field. Its pharmacokinetics show that it exhibits a typical long-acting sustained-release mechanism with slow absorption and low peak concentration. Although it has good safety, its rapid-acting properties are severely insufficient, making it difficult to meet the needs for rapid control of acute infections.

[0095] Comparative Example 2 improved the formulation by introducing a high proportion of polyethylene glycol; however, its pharmacokinetic data showed that this combination did not fundamentally solve the problem of rapid action; the time to peak concentration was still very long, and the peak concentration was only slightly increased; indicating that, under the conventional understanding in the field, simply mixing the solubilizer with ceftiofur mainly improves physical properties and enhances stability; it cannot bring about the expected synergistic effect of rapid and long-lasting action.

[0096] Comparative Example 3 is designed specifically for dairy cows. By introducing a variety of excipients, the injection solution has good dispersion stability and needle penetration. Its main purpose is to shorten the post-injection milk withdrawal period.

[0097] Example 1: Screening Experiment for Types and Dosage of Vegetable Oils

[0098] Samples 1-8 were prepared according to the component formulation in Table 4. The specific preparation method was the same as in Example 1, and the specific poloxamer used was poloxamer 188. The difference was that the amount of the specific components was adjusted accordingly based on the component formulation data in Table 4.

[0099] Table 4

[0100]

[0101] The specific preparation methods for samples 1-8 are the same as in Example 1, except that the dosage of specific components is adjusted accordingly based on the component formulation data in Table 2.

[0102] Following the standardized method described above, the pharmacokinetic parameters of the injection solutions for samples 1-8 were tested, and the results are shown in Table 5 below:

[0103] Table 5

[0104]

[0105] As shown in Table 5 above, when the applicant uses vegetable oils commonly used in injections in the field, such as soybean oil, corn oil, olive oil and peanut oil, although they perform well in other types of oil suspensions, the pharmacokinetic behavior of the formulation in the system of the present invention all show a serious loss of rapid effect.

[0106] Compared to Example 3 using sesame oil, their time to peak concentration (tpeak) was prolonged by more than 22%, and their peak plasma concentration (C) was lower. max The effect was reduced by nearly 40%. This result indicates that these commonly used vegetable oils have a negative interaction with the polyethylene glycol and caprylic / capric triglyceride system of this invention, hindering the rapid release and absorption of the drug, and their technical effect cannot meet the purpose of this invention to achieve both rapid and long-lasting effects. In stark contrast, the formulation using sesame oil perfectly demonstrates the combination of rapid and long-lasting effects. The applicant speculates that this may be due to an unexpected synergistic effect produced by the unique physicochemical properties of sesame oil, such as its low viscosity and good interfacial compatibility, with the polyethylene glycol-800 / caprylic / capric triglyceride system, thereby ensuring the rapid release of the dissolved drug.

[0107] After determining sesame oil as the preferred vegetable oil, the applicant further investigated its dosage range. Data showed that when the amount of sesame oil used was less than 22 parts or more than 30 parts as specified in this invention, the peak concentration (C0) of the formulation was... max Both the total drug exposure (AUC) and total drug exposure (TDA) decreased to varying degrees. This demonstrates that 22-30 parts is a key range for sesame oil to exert its optimal synergistic effect in this system.

[0108] Experimental Example 2: Screening Test for Molecular Weight and Dosage of Polyethylene Glycol

[0109] Samples 9-17 were prepared according to the component formulation in Table 6. The specific preparation method was the same as in Example 1, and the specific poloxamer used was poloxamer 188. The difference was that the amount of the specific components was adjusted accordingly based on the component formulation data in Table 5.

[0110] Table 6

[0111]

[0112] Following the standardized method described above, the pharmacokinetic parameters of the injection solutions of samples 9-17 were tested, and the results are shown in Table 7 below:

[0113] Table 7

[0114]

[0115] As shown in Table 7 above, during the screening of polyethylene glycol molecular weight, the applicant unexpectedly discovered that when using low molecular weight polyethylene glycol-400 and polyethylene glycol-200, the elimination half-life (t) of the formulation was... 1 / 2 (K e The peak concentration (C) is drastically shortened, and the long-lasting properties are almost completely lost. However, when high molecular weight polyethylene glycol-2000 is used, its peak concentration (C) is significantly reduced. max The time to peak concentration (tpeak) is significantly reduced, and the rapid-acting properties cannot meet clinical needs.

[0116] Only when the molecular weight of polyethylene glycol is strictly controlled within the range of 600-1000 can the formulation simultaneously achieve high peak drug concentration and long elimination half-life. This stringent requirement for molecular weight is something that those skilled in the art could not have foreseen.

[0117] After the applicant determined polyethylene glycol-800 to be the optimal molecular weight, we investigated its dosage. The results showed that the dosage of polyethylene glycol is crucial in determining the ratio of immediate-release to sustained-release fractions. When the dosage is below 32 parts, the peak concentration (C0.05) of the formulation is significantly lower. max The peak concentration was significantly reduced, resulting in insufficient rapid action, and its pharmacokinetic behavior tended to be similar to that of traditional pure oil suspensions. When the dosage was higher than 45 parts, although the peak concentration further increased, its elimination half-life and total drug exposure (AUC) decreased significantly, and the long-acting advantage disappeared.

[0118] In summary, the applicant's precise determination of the molecular weight and dosage of polyethylene glycol is based on in-depth research into drug distribution and release kinetics. Through creative experimental work, an optimal parameter space was found that can synergistically solve the seemingly contradictory problem of rapid-acting versus long-acting drugs.

[0119] Process optimization

[0120] Process 1: Following the formulation of Example 3, the specific preparation process is as follows, including step A: Add the total amount of sesame oil and caprylic / capric glyceride to a clean oil phase preparation tank and mix thoroughly. Heat to 160-170℃ and sterilize by dry heat for 2 hours. After sterilization, cool the mixed oil to 120℃ under sterile compressed air or nitrogen protection. While stirring, add the prescribed amount of hydrogenated castor oil and maintain stirring at 120℃ for 5-10 minutes. Subsequently, while stirring slowly and controlling the cooling rate, start the programmed cooling program to cool to room temperature (25℃) at a rate of 1℃ / min; then execute steps B, C, and D to complete the preparation of ceftiofur injection.

[0121] Process 2: Following the formulation of Example 3, the specific preparation process is as follows, including step A: Add the total amount of sesame oil and caprylic / capric glyceride to a clean oil phase preparation tank and mix thoroughly. Heat to 160-170℃ and sterilize by dry heat for 2 hours. After sterilization, cool the mixed oil to 120℃ under sterile compressed air or nitrogen protection. While stirring, add the prescribed amount of hydrogenated castor oil and maintain stirring at 120℃ for 5-10 minutes. Subsequently, under slow stirring and controlled cooling rate, start the programmed cooling program to cool to room temperature (25℃) at a rate of 0.5℃ / min; then execute steps B, C, and D to complete the preparation of ceftiofur injection.

[0122] Process 3: Following the formulation of Example 3, the specific preparation process is as follows, including step A: Add the total amount of sesame oil and caprylic / capric glyceride to a clean oil phase preparation tank and mix thoroughly. Heat to 160-170℃ and sterilize by dry heat for 2 hours. After sterilization, cool the mixed oil to 120℃ under sterile compressed air or nitrogen protection. While stirring, add the prescribed amount of hydrogenated castor oil and maintain stirring at 120℃ for 5-10 minutes. Subsequently, under slow stirring and controlled cooling rate, start the programmed cooling program to cool to room temperature (25℃) at a rate of 0.2℃ / min; then execute steps B, C, and D to complete the preparation of ceftiofur injection.

[0123] Process 4: Following the formulation of Example 3, the specific preparation process is as follows, including step A: Add the total amount of sesame oil and caprylic / capric glyceride to a clean oil phase preparation tank and mix thoroughly. Heat to 160-170℃ and sterilize by dry heat for 2 hours. After sterilization, cool the mixed oil to 120℃ under sterile compressed air or nitrogen protection. While stirring, add the prescribed amount of hydrogenated castor oil and maintain stirring at 120℃ for 5-10 minutes. Then, place it in an ice-water bath and rapidly cool to room temperature (25℃); subsequently, perform steps B, C, and D to complete the preparation of ceftiofur injection.

[0124] The samples prepared by the above process were inspected for product quality and accelerated testing (temperature 40℃±2℃, relative humidity 75%±5%) according to the compilation of veterinary drug quality standards, the quality standard of ceftiofur crystal injection, and the appendix standards of the Chinese Veterinary Pharmacopoeia. After 6 months, the pharmacokinetic parameters of the samples prepared by the above process were determined again, and the results are shown in Table 8 below:

[0125] Table 8

[0126]

[0127] The applicant discovered that process optimization, particularly by controlling the cooling rate, can greatly enhance the key to the stable efficacy of the formulation after long-term storage, and its effect is unpredictable.

[0128] By comparing the results of processes 1, 2, 3, and 4, it is clear that the pharmacokinetic characteristics of samples prepared using different cooling rates diverged significantly after 6 months of accelerated storage. Process 4, which used rapid cooling, resulted in severely degraded sample performance, with a significantly lower peak concentration (C0). max The concentration of the product decreased by more than 40%, and the time to peak (tpeak) was also significantly delayed, almost completely negating the rapid-acting advantage of this invention. This demonstrates that simple physical mixing cannot produce a stable product that can be stored stably for a long period of time.

[0129] The applicant unexpectedly discovered that a slower cooling rate is not necessarily better; when the cooling rate is too slow (Process 3, 0.2℃ / min) or too fast (Process 1, 1℃ / min), the long-term stability of the product is not as good as that of Process 2, which uses a cooling rate of 0.5℃ / min. The applicant hypothesizes that this specific cooling rate of 0.5℃ / min can guide the formation of an optimal and stable network framework in the system of sesame oil, caprylic / capric triglyceride, and hydrogenated castor oil. This optimized framework can lock in drug particles for a long time, effectively suppressing physical instability, and the pharmacokinetic data of the sample from Process 2, which uses the optimal cooling rate, after long-term storage are almost statistically different from those of the optimal example 3, which is prepared and used immediately. This ensures the uniformity and stability of the product's efficacy throughout its shelf life to the greatest extent.

[0130] For purposes of description and disclosure, all patents, patent applications, and other publications are expressly incorporated herein by reference. These publications are provided solely because their publication predates the filing date of this application. All statements regarding the dates of these documents or representations of their contents are based on information available to the applicant and do not constitute any acknowledgment of the accuracy of the dates or contents of these documents. Furthermore, in any country, any reference to these publications herein does not constitute an endorsement that such publication is part of the general knowledge in the art.

[0131] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A ceftiofur injection solution, characterized in that, Each 100g injection solution comprises: 10g ceftiofur, 0.6g hydrogenated castor oil, 0.4g poloxamer, 28-36g polyethylene glycol, 22-30g sesame oil, and the balance being caprylic / capric glyceride; the polyethylene glycol has a molecular weight of 600-1000; The ceftiofur injection is prepared by a formulation process comprising the following steps: Step A: Add the total amount of sesame oil and caprylic / capric triglycerides to the oil phase preparation tank and mix thoroughly; heat to 160-170℃ and dry heat sterilize for 2 hours; after sterilization, cool the mixed oil to 120℃ under sterile compressed air or nitrogen protection; while stirring, add the prescribed amount of hydrogenated castor oil and maintain at 120℃ for 5-10 minutes; then, while stirring slowly, control the cooling rate to cool to room temperature (25℃) at a rate of 0.2℃ / min-1℃ / min. Step B: In a sterile preparation tank, add the prescribed amount of polyethylene glycol, heat to 40-50°C, add the prescribed amount of poloxamer, and stir until completely dissolved to obtain a polyethylene glycol-poloxamer solution; under continuous stirring, add sterile ceftiofur active pharmaceutical ingredient in batches and slowly to the polyethylene glycol-poloxamer solution through a sterile feeding system, and continue stirring for 30 minutes to form an initial dispersion; Step C: Transfer all the matrix prepared in step A to the sterile preparation tank in step B, turn on the high shear disperser, and shear for 15-20 minutes to form a suspension; Step D: Homogenize the suspension prepared in step C using a pre-sterilized high-pressure homogenizer for 5-8 cycles; after homogenization, dispense the suspension into sterilized vials under nitrogen protection, and then stopper and cap them.

2. The ceftiofur injection according to claim 1, characterized in that, The molecular weight of the polyethylene glycol is 800.

3. The ceftiofur injection according to claim 1, characterized in that, Each 100g injection solution consists of the following components: 10g ceftiofur, 0.6g hydrogenated castor oil, 0.4g poloxamer, 36g polyethylene glycol, 25g sesame oil, and 28g caprylic / capric triglyceride.

4. The ceftiofur injection according to claim 1, characterized in that, The cooling rate in step A is 0.5°C / min to room temperature (25°C).

5. The ceftiofur injection according to claim 1, characterized in that, The homogenization pressure in step D is 800-1000 bar.

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