A solubilized stable solution of toltrazuril for poultry containing an amphiphilic polymer and a process for its preparation

Abstract

The present application relates to a kind of solubilizing stable solution of toltrazuril for poultry containing amphiphilic polymer, it is mainly composed of the following proportion of raw materials: toltrazuril 2.0-2.5%, amphiphilic polymer stabilizer 5-15%, triethanolamine 4-8%, PEG200 15-35%, the rest is water.The solubilizing stable solution of toltrazuril for poultry is maintained by amphiphilic polymer stabilizer solubility and long-term stability of toltrazuril, substantially reduce the amount of organic solvent, with environmental protection and cost advantage.

Description

[0001] This invention belongs to the field of veterinary drug formulation technology, specifically relating to a tortuzumab poultry solubilizing and stabilizing solution containing an amphiphilic polymer and its preparation method. It is a 2.5% tortuzumab clear drinking water solution for poultry that uses an amphiphilic polymer as a stabilizer and does not contain an oil phase. Background Technology

[0002] Many existing solubilization routes have been reported, such as: cyclodextrin inclusion (CN108653217B), oil-phase microemulsion (CN101336901 / CN101766564A), nano-suspension (CN102973502A), solid dispersion (PEG6000), etc.

[0003] It should be noted that the original research product of toltrazuril 2.5% poultry oral solution is Baycox® from Bayer AG, Germany. Its publicly disclosed formulation consists of toltrazuril 2.5% (w / v), triethanolamine, and macrogol 200 (i.e., polyethylene glycol 200) (see Baycox 2.5% Oral Solution SPC, HPRA VPA10021 / 019 / 001). This formulation is shared by several approved generic products both domestically and internationally and is considered public knowledge. The compound patent for toltrazuril (in China) expired in 2003, and the original formulation patent has also expired, placing the basic formulation in the public domain. The registered storage conditions for this reference formulation are: store in a cool, dark, dry place in a sealed container; shelf life is 24 months.

[0004] However, this classic formulation (triethanolamine + PEG200 (non-aqueous system, Bayer standard only residual moisture ≤2%)) has a recognized drawback: under long-term storage conditions at 2-8℃, toltrazuril alkaline solution is prone to slow precipitation (crystal precipitation), and there is a risk of drug precipitation due to pH decrease after dilution with drinking water (1.4 mL / L), affecting the safety and efficacy of clinical administration. Furthermore, this classic formulation is a non-aqueous system (with PEG200 and triethanolamine as the liquid matrix), requiring a large amount of organic solvent, resulting in high cost. Existing technologies have mostly attempted to improve this by changing the type of co-solvent (propylene glycol, DMSO, etc.) or using a microemulsion / cyclodextrin route, but none have solved the precipitation problem by adding an amphiphilic polymer stabilizer while retaining the "triethanolamine-PEG200 alkaline system". In view of this, this application was developed. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of the prior art and provide a tortozure poultry solubilizing and stabilizing solution containing an amphiphilic polymer. This solution maintains the solubility and long-term stability of tortozure through an amphiphilic polymer stabilizer, which significantly reduces the amount of organic solvent used and has both environmental and cost advantages.

[0006] The present invention also provides a method for preparing the above-mentioned tortuzumab poultry solubilizing and stabilizing solution containing the amphiphilic polymer.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A toltrazuril solubilizing and stabilizing solution for poultry containing an amphiphilic polymer is mainly composed of the following raw materials in the following proportions: toltrazuril 2.0-2.5%, amphiphilic polymer stabilizer 5-15%, triethanolamine 4-8%, PEG200 15-35%, and the balance being water. This proportion can be a mass percentage or a mass-volume ratio (w / v, e.g., g / ml). This invention's system does not contain any oil phase, unlike microemulsion routes containing an oil phase.

[0008] Specifically, the amphiphilic polymer stabilizer includes, but is not limited to, one or more combinations of Solutol HS 15 (polyethylene glycol-15 hydroxystearate), poloxamer 188, Cremophor RH 40 (polyoxyethylene hydrogenated castor oil RH-40), etc.

[0009] Furthermore, the amphiphilic polymer stabilizer is preferably 10-12%.

[0010] Furthermore, the triethanolamine is preferably 6%.

[0011] This invention provides a method for preparing the above-mentioned toltrazuril poultry solubilizing and stabilizing solution, which includes the following steps: (a) Disperse the amphiphilic polymer stabilizer in a portion of water, add PEG200 and mix well, then add triethanolamine (to adjust the pH of the system to 8.0–10.0). (b) Add tortrol and stir at 50-65°C until completely dissolved to form a clear solution; (c) Cool to room temperature, then add water to the full volume; (d) After filtration through a microporous membrane, the product is filled into containers.

[0012] Specifically, nitrogen is used to protect the feeding process in step (a) and the dissolution process in step (b).

[0013] Furthermore, in step (a), the amphiphilic polymer stabilizer is added to a portion of the water and heated to 40-65°C with stirring to disperse and dissolve. Solutol HS 15 and Cremophor RH 40 need to be preheated to approximately 40°C to melt and flow before being added.

[0014] Furthermore, in step (d), filtration is performed using a 0.22 μm microporous membrane.

[0015] This invention also provides the application of the above-mentioned toltrazuril poultry solubilizing and stabilizing solution in the preparation of poultry anticoccidial drinking water formulations.

[0016] One of the key improvements of this invention is that the original non-aqueous system (PEG200 + triethanolamine only) is replaced with an aqueous solution system with water as the main solvent (water accounts for about 82%). The amphiphilic polymer stabilizer maintains the solubility and long-term stability of tortezulide, which greatly reduces the amount of organic solvent used and has both environmental and cost advantages.

[0017] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1) This invention uses an oil-free amphiphilic polymer (Solutol HS 15 / Poloxamer 188 / Cremophor RH 40), which has a stable drug loading (2.5%), does not precipitate at low temperatures, and has a cleaner process; 2) Compared to cyclodextrin, the drug loading is more stable; the inclusion complex route has a solid inclusion rate of about 7% and a saturated solubility of only about 0.99% (9.90 mg / mL; Journal of Process Engineering 2012), which is far lower than the commercial concentration of 2.5%; 3) Compared to the microemulsion route, this invention eliminates the burden of oil phase transportation and equipment cleaning; it does not precipitate even after long-term use at 2-8℃, and remains clear and precipitate within 24 hours after dilution in drinking water at 1.4 mL / L; thus improving bioavailability. Furthermore, this invention features a simple process and requires less organic solvent, making it suitable for industrial production. Detailed Implementation

[0018] The technical solution of the present invention will be further described in detail below with reference to the embodiments, but the scope of protection of the present invention is not limited thereto.

[0019] In the following examples, all raw materials used are common commercially available products that can be purchased directly, or can be prepared using conventional techniques in the art.

[0020] Room temperature refers to 25±5℃. Example 1

[0021] In this embodiment, the preferred amphiphilic polymer stabilizer is Solutol HS 15.

[0022] A toltrazuril poultry solubilizing and stabilizing solution containing an amphiphilic polymer is mainly composed of the following raw materials in the specified proportions: The composition is as follows: 2.5% toltrazuril, 12% amphiphilic polymer stabilizer (Solutol HS 15), 6% triethanolamine, 20% PEG200, and the balance is water.

[0023] The above-mentioned toltrazuril poultry solubilizing and stabilizing solution containing amphiphilic polymers is prepared as follows: 1) Take 400g of water (part of the prescribed amount) and heat to approximately 55°C. Take 120g of Solutol HS 15 (pre-melted in a water bath at approximately 40°C until flowable) and add it to the hot water while stirring, dispersing evenly. Add 200g of PEG200 and continue stirring for 5 minutes. Add 60g of triethanolamine and stir until homogeneous (pH measured to be approximately 9.0). 2) Add 25g of tortuzumab and keep warm at 55-60℃ while stirring until completely dissolved to form a clear, slightly yellow solution; the addition of the ingredients in step 1) and the dissolution process in step 2) are protected by nitrogen. 3) Cool to room temperature, then add water to a final volume of 1000 mL; 4) Filtered through a 0.22 μm microporous membrane and filled into HDPE bottles.

[0024] The toltrazuril poultry solubilizing and stabilizing solution prepared in this embodiment has a turbidity of <1 NTU and a content of approximately 2.5% (w / v). Example 2

[0025] In this embodiment, poloxamer 188 is used instead of Solutol HS 15, and the rest is the same as in embodiment 1.

[0026] The turbidity of the toltrazuril poultry solubilization and stabilization solution prepared in this embodiment is <1 NTU.

[0027] Example 3

[0028] In this embodiment, Cremophor RH 40 is used instead of Solutol HS 15, and the rest is the same as in Embodiment 1.

[0029] The turbidity of the toltrazuril poultry solubilization and stabilization solution prepared in this embodiment is <1 NTU.

[0030] Comparative Example 1 (Cyclodextrin)

[0031] The SBE-β-CD inclusion complex prepared according to CN108653217B has a drug loading of only 7%, demonstrating its advantage in drug loading.

[0032] Comparative Example 2 (Microemulsion)

[0033] Prepare oil-containing microemulsions according to CN101336901, with an oil phase content of 15%, which has a high transportation / cleaning burden.

[0034] Comparative Example 3 (Bayer's classic formulation, without polymer stabilizers)

[0035] The formula is the same as that of Bayer Baiqiuqing® (triethanolamine + PEG200 + toltrazuril 2.5% (non-aqueous system, with only residual moisture ≤2%), without the addition of any amphiphilic polymers, and otherwise the same as in Example 1.

[0036] The prescription is the well-known Baycox 2.5% oral solution prescription, and the results are as follows.

[0037]

[0038] The above results indicate that classic Bayer formulations lacking amphiphilic polymers exhibit crystal precipitation and decreased content after long-term storage at 2-8°C, posing a risk of precipitation at low temperatures. This data directly demonstrates the crucial role of the amphiphilic polymer stabilizer described in this invention in preventing low-temperature crystallization and maintaining long-term solution stability.

[0039] Effect verification.

[0040] (a) Solubility and solubilization factor.

[0041] Toltrazuril belongs to the BCS class II (low-soluble, high-osmotic) drugs. Publicly available literature reports that its solubility in water at 25°C is only 0.41 μg / mL (Colloids Surf B 2018, 161: 213–220), confirming its extremely poor water solubility. The solubilization of this invention relies on a triple synergistic effect: In alkaline environments (pH 8.0-10.0): toltrazuril pKa≈6.47, exists in ionic form within this pH range, and its intrinsic solubility is greatly enhanced.

[0042] PEG200 solubilizer: As a non-toxic cosolvent, it significantly increases the molecular dispersion of toltrazuril in the liquid phase.

[0043] Amphiphilic polymers (Solutol HS 15 / Poloxamer 188 / Cremophor RH 40): In a moderately alkaline environment, they inhibit drug molecule aggregation and precipitation through wetting, dispersion, and steric stabilization, forming a homogeneous and clear aqueous solution. Note: Poloxamer 188 has an extremely high critical micelle concentration (CMC) in pure water at room temperature and does not form micelles. The solubilization mechanism of this invention differs from traditional micelle solubilization; instead, it involves alkaline ionization + co-solvent + synergistic solubilization and stabilization by the amphiphilic polymer.

[0044] Poloxamer 188 is an FDA-approved excipient for oral formulations and is widely used in solid dispersions, solubilization, emulsification, and other fields. However, its application as a low-temperature anti-crystallization stabilizer in alkaline toltrazuril solution systems has not been reported.

[0045] The measured solubility of tortrazuril in pure water at 25°C is approximately 0.41 μg / mL. However, the complete tortrazuril solubilization and stabilization solution system for poultry produced in this invention exhibits a solubility of ≥100 mg / mL (10% w / v), with a solubilization factor of approximately 2.4 × 10⁻⁶. 5 times.

[0046] (ii) Characterization of formulation quality.

[0047] The relevant quality characterization of the product in Example 1 is shown in the table below. The data in the table demonstrate that the toltrazuril poultry solubilizing and stabilizing solution of the present invention meets the relevant quality standards.

[0048]

[0049] (III) Low temperature stability test (2-8℃, multi-scenario applicability verification).

[0050] The product of Example 1 was subjected to relevant tests in accordance with the "Technical Guidelines for Veterinary Drug Stability Testing", and the results are shown in the table below.

[0051]

[0052] The results in the table above show that the product of Example 1 remained clear after being stored at a low temperature of 2-8°C for 24 months. This result indicates that, compared to commercially available products and Comparative Examples 1 to 3, there is a risk of precipitation at low temperatures. The measurement results of the product of Example 1 in the table above directly demonstrate the crucial role of the amphiphilic polymer stabilizer described in this invention in preventing low-temperature crystallization and maintaining long-term solution stability.

[0053] (iv) Accelerated stability test (40℃ / 75% RH, June).

[0054]

[0055] The results in the table above show that: after 6 months of accelerated processing, the content of the product in Example 1 was still ≥97%, the related substances did not exceed 2%, and the appearance was clear, indicating that the system has good temperature tolerance.

[0056] (v) Stability in drinking water dilution (diluted at 1.4 mL / L in tap water, pH≈7.0-7.5, simulating clinical administration).

[0057] The clinical drinking water concentration is approximately 35 μg / mL, which far exceeds the solubility of toltrazuril in pure water (0.41 μg / mL). However, thanks to the synergistic effect of alkaline ionization and polymer steric hindrance / wetting, the drug in the product of Example 1 remains dispersed and does not precipitate.

[0058]

[0059] As can be seen from the data in the table above, the drug in Example 1 of this application does not precipitate or separate within 24 hours after dilution, meeting the 24-hour drug administration window requirement for clinical drinking water administration.

[0060] (vi) Comparison with existing technologies.

[0061] The toltrazuril solubilization routes reported in the literature and those of commercially available products are compared with those of this invention as follows.

[0062]

[0063] This invention adds an amphiphilic polymer stabilizer to its original basic formulation (triethanolamine + PEG200 + toltrazuril, a non-aqueous system), enabling the product to remain clear and maintain a content ≥98.3% during long-term storage (over 24 months) at 2–8°C. This expands the applicability of the formulation in harsh environments such as low temperatures, achieving a substantial improvement that is not immediately obvious. Compared to other routes (cyclodextrin, solid dispersions, nanomicelles), this invention achieves a superior technical level with an oil-free phase system.

[0064] (vii) Content variation and microbial limits.

[0065] Content variation (three pilot batches, 1L / 5L HDPE bottles): All three batches were within the range of 98.5%-101.2% of the labeled content, with RSD < 1.5%, which meets the requirements for solution content in the Chinese Veterinary Pharmacopoeia.

[0066] Microbial limits: Total aerobic bacteria count <10² CFU / mL, no Escherichia coli or Salmonella detected.

[0067] (viii) Pharmacodynamics (Chicken Eimeria tenella infection model, 7 mg / kg × 2 days).

[0068] Publicly available efficacy data for the marketed reference formulation, Baiqiuqing®, show a reduction in ovarian cysts of ≥99% and a significant decrease in lesion scores. The alkaline solubilizing system of this product is consistent with the basic formulation of Baiqiuqing®. The added poloxamer 188 is an FDA-approved oral excipient and does not affect pharmacological activity.

Claims

1. A toluene-stabilizing and solubilizing solution for poultry containing an amphiphilic polymer, characterized in that, It is mainly composed of the following raw materials in the following proportions: toltrazuril 2.0-2.5%, amphiphilic polymer stabilizer 5-15%, triethanolamine 4-8%, PEG200 15-35%, and the balance is water.

2. The toltrazuril poultry solubilizing and stabilizing solution according to claim 1, characterized in that, The amphiphilic polymer stabilizer is one or more of Solutol HS 15, poloxamer 188, and Cremophor RH 40.

3. The toltrazuril poultry solubilizing and stabilizing solution according to claim 1, characterized in that, The amphiphilic polymer stabilizer is 10-12%.

4. The toltrazuril poultry solubilizing and stabilizing solution according to claim 1, characterized in that, The triethanolamine content is 6%.

5. The method for preparing the poultry solubilizing and stabilizing solution of tortrol according to any one of claims 1 to 4, characterized in that, Includes the following steps: (a) Disperse the amphiphilic polymer stabilizer in a portion of water, add PEG200 and mix well, then add triethanolamine; (b) Add tortrol and stir at 50-65°C until completely dissolved to form a clear solution; (c) Cool to room temperature, then add water to the full volume; (d) After filtration through a microporous membrane, the product is filled into containers.

6. The preparation method according to claim 5, characterized in that, The feeding process in step (a) and the dissolution process in step (b) are protected by nitrogen.

7. The preparation method according to claim 5, characterized in that, In step (a), the amphiphilic polymer stabilizer is added to a portion of water and heated to 40-65°C with stirring to disperse and dissolve.

8. The preparation method according to claim 5, characterized in that, In step (d), filtration is performed using a 0.22 μm microporous membrane.

9. The use of the toltrazuril poultry solubilizing and stabilizing solution according to any one of claims 1 to 4 in the preparation of poultry anticoccidial drinking water formulations.

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