A method for preparing atosiban acetate
By optimizing the preparation method of atosiban acetate, and adopting a process of amide resin deprotection, amino acid monomer reaction and cyclization purification, the problems of insufficient purity and yield in the existing process have been solved, and high-purity and high-yield atosiban acetate production has been achieved, which is suitable for industrial application.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- STARTBAHNWEST AG
- Filing Date
- 2026-05-11
- Publication Date
- 2026-06-30
AI Technical Summary
The existing production process for atosiban acetate has limitations in terms of product purity and yield, making it difficult to meet the requirements for high-quality drugs.
The purification process involved removing Fmoc protection by swelling amide resin, followed by activation, coupling, and deprotection reactions of amino acid monomers, combined with the cleavage, cyclization, and reversed-phase HPLC purification of linear atosiban resin, cyclization reaction with dimethyl sulfoxide aqueous solution and oxygen, and filtration with diatomaceous earth and microporous membranes to optimize the purification process.
It significantly improves the purity and yield of atosiban acetate, reduces side reactions and solvent residues, lowers production costs, and is suitable for industrial production.
Smart Images
Figure CN122301985A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polypeptide synthesis technology, and in particular to a method for preparing atosiban acetate. Background Technology
[0002] Atosiban acetate is a peptide drug used to delay preterm labor. Its active ingredient is a synthetic nonapeptide acetate. This drug works by competitively antagonizing oxytocin receptors on uterine smooth muscle, effectively blocking oxytocin-mediated uterine contraction signals. For pregnant women aged 18 years or older with normal fetal heart rate and signs of preterm labor at 24 to 33 weeks of gestation, timely administration of a therapeutic dose of atosiban acetate usually significantly reduces the frequency of uterine contractions within 10 minutes of administration, helping the uterus return to a stable state and thus providing the fetus with more time for intrauterine development.
[0003] Given its proven clinical efficacy, atosiban acetate has promising application prospects and development value. The quality, safety, and ultimate efficacy of this drug depend on the chemical purity of its active ingredient, which is closely related to the production process. Currently, the production process of this drug still faces some challenges, and there is room for further improvement in the purity and yield of the final product. Therefore, developing a high-yield, high-purity production process for atosiban acetate has significant practical implications and application value. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing atosiban acetate, which has a high yield and can produce atosiban acetate product with high purity.
[0005] To achieve the above objectives, the present invention provides a method for preparing atosiban acetate, comprising the following steps: S1. After the amide resin is swollen, it is placed in a descaling agent solution to obtain an amide resin with Fmoc protection removed. S2. Select amino acid monomers according to the amino acid sequence of atosiban. First, mix Fmoc-Gly-OH with the activating agent and then add a condensing agent. Activate the reaction under solvent conditions to obtain activated Fmoc-Gly-OH. The amino acid monomers include: Fmoc-Gly-OH, Fmoc-Orn(Boc)-OH, Fmoc-Pro-OH, Fmoc-Cys(Trt)-OH, Fmoc-Asn(Trt)-OH, Fmoc-Thr(tBu)-OH, Fmoc-Ile-OH, Fmoc-D-Tyr(Et)-OH, and Mpa(Trt)-OH; S3. After mixing the activated Fmoc-Gly-OH with the amide resin after removing Fmoc protection, the coupling reaction and the Fmoc protection removal reaction are carried out in sequence. Then, according to the amino acid sequence of atosiban from C-terminus to N-terminus, the remaining amino acid monomers are sequentially activated, coupled and removed to obtain linear atosiban resin. S4. The linear atosiban resin peptide is mixed and stirred with a lysis reagent and then post-treated to obtain crude linear atosiban. S5. The crude linear atosiban was placed in a dimethyl sulfoxide aqueous solution to obtain a mixed solution. The pH of the mixed solution was adjusted to 7-8.5, and oxygen was introduced to carry out the cyclization reaction. After the cyclization reaction was completed, the reaction solution was filtered through diatomaceous earth and microporous membrane in sequence to obtain the filtrate. The filtrate was separated and purified by reversed-phase HPLC, and after salting and freeze-drying, atosiban acetate was obtained.
[0006] Preferably, the amide resin in S1 includes Rink MBHA resin, Rink Amide resin, or Rink Amide AM resin.
[0007] Preferably, the swelling process of the amide resin in S1 includes: immersing the amide resin in N,N-dimethylformamide; the immersion temperature is 18-30°C and the time is 40-60 min.
[0008] Preferably, the remover solution in S1 is an N,N-dimethylformamide solution of the remover, with a volume fraction of 20%-30%, and the remover includes tetrahydropyrrole, morpholine, or piperidine.
[0009] After the amide resin is swollen, it is placed in a deprotection agent solution for deprotection reaction. After the deprotection reaction is completed, the amide resin is washed with N,N-dimethylformamide to remove the residual deprotection agent and obtain the amide resin with Fmoc protection removed.
[0010] Preferably, the activating agent in S2 includes 1-hydroxybenzotriazole, 1-hydroxy-7-azabenzotriazole, or 6-chloro-1-hydroxybenzotriazole; the condensing agent includes N,N'-diisopropylcarbodiimide or dicyclohexylcarbodiimide; the solvent is N,N-dimethylformamide; and the activation reaction is carried out at a temperature of 10-25°C for 1-3 hours.
[0011] This invention does not require the order of S1 and S2.
[0012] The amino acid sequence of atosiban is: Cyclo[Mpa-D-Tyr(Et)-Ile-Thr-Asn-Cys]-Pro-Orn-Gly-NH2.
[0013] Preferably, the coupling reaction in S3 is carried out under solvent conditions, wherein the solvent is N,N-dimethylformamide, the temperature of the coupling reaction is 18-30°C, and the time is 1-4 hours.
[0014] In an optional embodiment of the present invention, the coupling reaction is determined to be complete if the ninhydrin test is negative, and then a deprotection solution is added to carry out the Fmoc deprotection reaction.
[0015] Preferably, the Fmoc deprotection reaction in S3 is carried out under deprotection solution conditions, wherein the deprotection solution is an N,N-dimethylformamide solution of a deprotecting agent, and the deprotecting agent includes piperidine, morpholine, or tetrahydropyrrole.
[0016] Preferably, the cleavage reagent in S4 includes a triisopropylsilane system or anisole sulfide system; the triisopropylsilane system includes trifluoroacetic acid, triisopropylsilane, and water, and the volume ratio of trifluoroacetic acid, triisopropylsilane, and water is 95:2-3:2-3; the anisole sulfide system includes trifluoroacetic acid, water, anisole, and ethylenedithiol, and the volume ratio of trifluoroacetic acid, water, anisole, and ethylenedithiol is 90:5:2-3:2-3.
[0017] The above-mentioned lysis reagent can effectively protect the thiol structure in the polypeptide chain and reduce side chain side reactions; the post-processing and purification process is reasonably connected, and the precise separation by reversed-phase HPLC further improves the purity of the product while reducing the amount of organic solvent used.
[0018] In an optional embodiment of the present invention, the mixing and stirring temperature in S4 is 10-35°C and the time is 1-4 hours; the post-processing includes filtration, concentration, precipitation, washing and drying performed sequentially.
[0019] Preferably, the volume fraction of the dimethyl sulfoxide aqueous solution in S5 is 3%-10%; the mass concentration of the linear crude atosiban in the mixed solution is 0.01-0.03 g / mL; the oxygen flow rate is 0.1-0.5 L / min; and the cyclization reaction temperature is 18-30℃ and the time is 40-90 min.
[0020] When the volume fraction of dimethyl sulfoxide aqueous solution is 3%-10%, it can improve the problems of poor water solubility and easy aggregation and precipitation of crude linear atosiban, making the cyclization reaction system more uniform, the reaction more thorough, and further improving the cyclization yield.
[0021] In an optional embodiment of the present invention, the method of adjusting the pH of the mixed solution in S5 includes: adding ammonium bicarbonate or triethylamine to the mixed solution to adjust the pH of the mixed solution.
[0022] Preferably, the microporous filter membrane in S5 has a pore size of 0.22 μm; the reversed-phase HPLC purification uses a C18 column with a column temperature of 25-35℃, a mobile phase of acetonitrile-acetic acid aqueous solution, and a flow rate of 1.0-2.0 mL / min.
[0023] The present invention has the following beneficial effects: The present invention provides a method for preparing atosiban acetate with mild overall reaction conditions and few side reactions, which can effectively reduce peptide chain degradation and impurity generation, significantly improve the product purity and final yield of atosiban acetate, and more easily meet the quality requirements of injectable polypeptide drugs.
[0024] In this invention, the cyclization reaction in S5 is carried out by using dimethyl sulfoxide aqueous solution and oxygen, which replaces the reagents such as hydrogen peroxide and ammonia water in the traditional process that are prone to introducing residues and by-products. This avoids problems such as solvent residues, and the finished product is safer and has better purity.
[0025] This invention employs a dual filtration method using a diatomaceous earth microporous membrane before reversed-phase HPLC separation and purification. This method can remove insoluble particulate matter from the reaction solution in advance, effectively reducing contamination and column pressure loss of the reversed-phase HPLC column, extending the column's lifespan, and reducing industrial purification costs.
[0026] The preparation process of this invention is simple to operate, and the parameters used in each step are all conventional industrial conditions. No special equipment is required, and the controllability and repeatability of the operation are good. It is easy to realize large-scale industrial production, effectively reducing the production difficulty and production cost, and has industrial application value and clinical promotion prospects.
[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0028] Figure 1 This is the HPLC chromatogram of atosiban acetate obtained in Example 1 of the present invention. Detailed Implementation
[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.
[0030] The amino acid monomers in the following examples are: Fmoc-Gly-OH, Fmoc-Orn(Boc)-OH, Fmoc-Pro-OH, Fmoc-Cys(Trt)-OH, Fmoc-Asn(Trt)-OH, Fmoc-Thr(tBu)-OH, Fmoc-Ile-OH, Fmoc-D-Tyr(Et)-OH, and Mpa(Trt)-OH.
[0031] Example 1 This embodiment provides a method for preparing atosiban acetate, the process of which is as follows: S1. Weigh 5g of Rink MBHA resin and soak it in N,N-dimethylformamide (DMF) at 25°C for 40min to allow the amide resin to swell. Then, place it in a 20% (v / v) N,N-dimethylformamide solution (deprotecting agent solution) for deprotection reaction. Afterward, wash the amide resin with N,N-dimethylformamide to remove residual piperidine and detect it with ninhydrin. The result is reddish-brown, indicating that the amide resin has been deprotected from Fmoc.
[0032] S2. Fmoc-Gly-OH, 1-hydroxybenzotriazole (activating agent), N,N'-diisopropylcarbodiimide (condensing agent), and N,N-dimethylformamide (solvent) were mixed and reacted at 25°C for 2 hours. The reaction was then tested using the ninhydrin assay, and all results were negative. The mixture was then washed with N,N-dimethylformamide to obtain the activated Fmoc-Gly-OH.
[0033] S3. The activated Fmoc-Gly-OH and the amide resin with deprotected Fmoc were placed in N,N-dimethylformamide and coupled at 25°C for 2.5 h. The resin was tested negative by the ninhydrin detection method. After washing with N,N-dimethylformamide, it was placed in a 20% (v / v) piperidine N,N-dimethylformamide solution (deprotection solution) for the deprotection reaction. The ninhydrin test was positive. The resin was washed with N,N-dimethylformamide. Following step S3, Fmoc-Orn(Boc)-OH, Fmoc-Pro-OH, Fmoc-Cys(Trt)-OH, Fmoc-Asn(Trt)-OH, Fmoc-Thr(tBu)-OH, Fmoc-Ile-OH, Fmoc-D-Tyr(Et)-OH, and MPa(Trt)-OH are sequentially subjected to activation, coupling, and deprotection reactions to obtain linear atosiban resin (finally, MPa(Trt)-OH does not require deprotection). S4. The linear atosiban resin peptide was mixed with a lysis reagent (trifluoroacetic acid, triisopropylsilane, and water in a volume ratio of 95:2:3), stirred at 25°C for 2 hours, filtered to remove resin residue, concentrated the filtrate under reduced pressure, added ice-cold ether to precipitate, collected the precipitate by centrifugation, washed the precipitate three times with ice-cold ether, and dried under vacuum to obtain crude linear atosiban with a yield of 73%.
[0034] S5. The above-mentioned linear crude atosiban was placed in a 5% (v / v) dimethyl sulfoxide aqueous solution to obtain a mixed solution (the mass concentration of the linear crude atosiban in the mixed solution was 0.01 g / mL). Triethylamine was added to the mixed solution to adjust the pH to 7. Oxygen was introduced at a flow rate of 0.5 L / min for 60 min at 25 °C to carry out the cyclization reaction. After the cyclization reaction was completed, the reaction solution was sequentially filtered through diatomaceous earth for coarse filtration and 0.22 μm microporous membrane for fine filtration to obtain the filtrate. The filtrate was separated and purified by reversed-phase HPLC. After salting and lyophilization, atosiban acetate was obtained with an HPLC purity of 99.2%.
[0035] The reversed-phase HPLC used a C18 column at a temperature of 25°C, with an acetonitrile-acetic acid aqueous solution as the mobile phase and a flow rate of 1.0 mL / min.
[0036] The HPLC chromatogram of atosiban acetate obtained in this example is shown below. Figure 1 .
[0037] Example 2 This embodiment provides a method for preparing atosiban acetate, the process of which is as follows: S1. Weigh 5g of Rink Amide resin and soak it in N,N-dimethylformamide (DMF) at 18°C for 60min to allow the amide resin to swell. Then, place it in a 25% (v / v) solution of tetrahydropyrrole in N,N-dimethylformamide (deprotecting agent solution) for deprotection reaction. Afterward, wash the amide resin with N,N-dimethylformamide to remove residual tetrahydropyrrole, and test it with ninhydrin. The result is reddish-brown, indicating that the amide resin has been deprotected from Fmoc.
[0038] S2. Fmoc-Gly-OH, 1-hydroxy-7-azabenzotriazole (activating agent), dicyclohexylcarbodiimide (condensing agent), and N,N-dimethylformamide (solvent) were mixed and reacted at 10°C for 3 hours. The reaction was then tested using the ninhydrin assay, and all results were negative. The mixture was then washed with N,N-dimethylformamide to obtain the activated Fmoc-Gly-OH.
[0039] S3. The activated Fmoc-Gly-OH and the amide resin with deprotected Fmoc were placed in N,N-dimethylformamide and coupled at 30°C for 2 hours. The resin was tested negative by the ninhydrin detection method. After washing with N,N-dimethylformamide, it was placed in a 20% (v / v) solution of tetrahydropyrrole in N,N-dimethylformamide (deprotection solution) for the deprotection reaction. The ninhydrin detection was positive. The resin was then washed with N,N-dimethylformamide. Following step S3, Fmoc-Orn(Boc)-OH, Fmoc-Pro-OH, Fmoc-Cys(Trt)-OH, Fmoc-Asn(Trt)-OH, Fmoc-Thr(tBu)-OH, Fmoc-Ile-OH, Fmoc-D-Tyr(Et)-OH, and MPa(Trt)-OH are sequentially subjected to activation, coupling, and deprotection reactions to obtain linear atosiban resin (finally, MPa(Trt)-OH does not require deprotection). S4. The linear atosiban resin peptide was mixed with a lysis reagent (trifluoroacetic acid, water, anisole, and ethylenedithiol in a volume ratio of 90:5:3:2), stirred at 35°C for 1 hour, filtered to remove resin residue, concentrated the filtrate under reduced pressure, added ice-cold ether to precipitate, collected the precipitate by centrifugation, washed the precipitate three times with ice-cold ether, and dried under vacuum to obtain crude linear atosiban with a yield of 75%.
[0040] S5. The above-mentioned linear crude atosiban was placed in a 3% (v / v) dimethyl sulfoxide aqueous solution to obtain a mixed solution (the mass concentration of the linear crude atosiban in the mixed solution was 0.02 g / mL). Triethylamine was added to the mixed solution to adjust the pH to 7. Oxygen was introduced at a flow rate of 0.3 L / min for 90 min at 18 °C to carry out the cyclization reaction. After the cyclization reaction was completed, the reaction solution was sequentially filtered through diatomaceous earth for coarse filtration and 0.22 μm microporous membrane for fine filtration to obtain the filtrate. The filtrate was separated and purified by reversed-phase HPLC. After salting and lyophilization, atosiban acetate was obtained with an HPLC purity of 99.5%.
[0041] The reversed-phase HPLC used a C18 column at a temperature of 35℃, with an acetonitrile-acetic acid aqueous solution as the mobile phase and a flow rate of 2.0 mL / min.
[0042] Example 3 This embodiment provides a method for preparing atosiban acetate, the process of which is as follows: S1. Weigh 5g of Rink Amide AM resin and soak it in N,N-dimethylformamide (DMF) at 30℃ for 55min to allow the amide resin to swell. Then, place it in a 30% (v / v) N,N-dimethylformamide solution (deprotecting agent solution) for deprotection reaction. Afterward, wash the amide resin with N,N-dimethylformamide to remove residual morpholine and detect it with ninhydrin. The result is reddish-brown, indicating that the amide resin has been deprotected from Fmoc.
[0043] S2. Fmoc-Gly-OH, 6-chloro-1-hydroxybenzotriazole (activating agent), N,N'-diisopropylcarbodiimide (condensing agent), and N,N-dimethylformamide (solvent) were mixed and reacted at 25°C for 3 hours. The reaction was then tested using the ninhydrin assay, and all results were negative. The mixture was then washed with N,N-dimethylformamide to obtain the activated Fmoc-Gly-OH.
[0044] S3. The activated Fmoc-Gly-OH and the amide resin with deprotected Fmoc were placed in N,N-dimethylformamide and coupled at 25°C for 2 hours. The resin was tested negative by the ninhydrin detection method. After washing with N,N-dimethylformamide, it was placed in a 20% (v / v) solution of morpholine in N,N-dimethylformamide (deprotection solution) for the deprotection reaction. The ninhydrin detection was positive. The resin was then washed with N,N-dimethylformamide. Following step S3, Fmoc-Orn(Boc)-OH, Fmoc-Pro-OH, Fmoc-Cys(Trt)-OH, Fmoc-Asn(Trt)-OH, Fmoc-Thr(tBu)-OH, Fmoc-Ile-OH, Fmoc-D-Tyr(Et)-OH, and MPa(Trt)-OH are sequentially subjected to activation, coupling, and deprotection reactions to obtain linear atosiban resin (finally, MPa(Trt)-OH does not require deprotection). S4. The linear atosiban resin peptide was mixed with a lysis reagent (trifluoroacetic acid, triisopropylsilane, and water in a volume ratio of 95:3:2), stirred at 20°C for 4 hours, filtered to remove resin residue, concentrated the filtrate under reduced pressure, added ice-cold ether to precipitate, collected the precipitate by centrifugation, washed the precipitate three times with ice-cold ether, and dried under vacuum to obtain crude linear atosiban with a yield of 71%.
[0045] S5. The above-mentioned linear crude atosiban was placed in a 3% (v / v) dimethyl sulfoxide aqueous solution to obtain a mixed solution (the mass concentration of the linear crude atosiban in the mixed solution was 0.03 g / mL). Triethylamine was added to the mixed solution to adjust the pH to 7. Oxygen was introduced at a flow rate of 0.5 L / min for 45 min at 18 °C to carry out the cyclization reaction. After the cyclization reaction was completed, the reaction solution was sequentially filtered through diatomaceous earth for coarse filtration and 0.22 μm microporous membrane for fine filtration to obtain the filtrate. The filtrate was separated and purified by reversed-phase HPLC. After salting and lyophilization, atosiban acetate was obtained with an HPLC purity of 99.2%.
[0046] The reversed-phase HPLC used a C18 column at a temperature of 30°C, with an acetonitrile-acetic acid aqueous solution as the mobile phase and a flow rate of 1.5 mL / min.
[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A method for preparing atosiban acetate, characterized in that, Includes the following steps: S1. After the amide resin is swollen, it is placed in a descaling agent solution to obtain an amide resin with Fmoc protection removed. S2. Select amino acid monomers according to the amino acid sequence of atosiban. First, mix Fmoc-Gly-OH with the activating agent and then add a condensing agent. Activate the reaction under solvent conditions to obtain activated Fmoc-Gly-OH. The amino acid monomers include: Fmoc-Gly-OH, Fmoc-Orn(Boc)-OH, Fmoc-Pro-OH, Fmoc-Cys(Trt)-OH, Fmoc-Asn(Trt)-OH, Fmoc-Thr(tBu)-OH, Fmoc-Ile-OH, Fmoc-D-Tyr(Et)-OH, and Mpa(Trt)-OH; S3. After mixing the activated Fmoc-Gly-OH with the amide resin after removing Fmoc protection, the coupling reaction and the Fmoc protection removal reaction are carried out in sequence. Then, according to the amino acid sequence of atosiban from C-terminus to N-terminus, the remaining amino acid monomers are sequentially activated, coupled and removed to obtain linear atosiban resin. S4. The linear atosiban resin peptide is mixed and stirred with a lysis reagent and then post-treated to obtain crude linear atosiban. S5. The crude linear atosiban was placed in a dimethyl sulfoxide aqueous solution to obtain a mixed solution. The pH of the mixed solution was adjusted to 7-8.5, and oxygen was introduced to carry out the cyclization reaction. After the cyclization reaction was completed, the reaction solution was filtered through diatomaceous earth and microporous membrane in sequence to obtain the filtrate. The filtrate was separated and purified by reversed-phase HPLC, and after salting and freeze-drying, atosiban acetate was obtained.
2. The method for preparing atosiban acetate according to claim 1, characterized in that, The amide resin mentioned in S1 includes Rink MBHA resin, Rink Amide resin, or Rink Amide AM resin.
3. The method for preparing atosiban acetate according to claim 1, characterized in that, The swelling process of the amide resin described in S1 includes: immersing the amide resin in N,N-dimethylformamide; the immersion temperature is 18-30℃ and the time is 40-60min.
4. The method for preparing atosiban acetate according to claim 1, characterized in that, The removing agent solution mentioned in S1 is an N,N-dimethylformamide solution of the removing agent, which includes tetrahydropyrrole, morpholine, or piperidine.
5. The method for preparing atosiban acetate according to claim 1, characterized in that, The activating aids mentioned in S2 include 1-hydroxybenzotriazole, 1-hydroxy-7-azabenzotriazole or 6-chloro-1-hydroxybenzotriazole; The condensing agent includes N,N'-diisopropylcarbodiimide or dicyclohexylcarbodiimide; The solvent is N,N-dimethylformamide.
6. The method for preparing atosiban acetate according to claim 1, characterized in that, The coupling reaction described in S3 is carried out under solvent conditions, wherein the solvent is N,N-dimethylformamide, and the temperature of the coupling reaction is 18-30℃, and the time is 1-4h.
7. The method for preparing atosiban acetate according to claim 1, characterized in that, The Fmoc deprotection reaction described in S3 is carried out under deprotection solution conditions, wherein the deprotection solution is an N,N-dimethylformamide solution of a deprotecting agent, and the deprotecting agent includes piperidine, morpholine, or tetrahydropyrrole.
8. The method for preparing atosiban acetate according to claim 1, characterized in that, The cleavage reagents described in S4 include triisopropylsilane systems or anisole sulfide systems; The triisopropylsilane system comprises trifluoroacetic acid, triisopropylsilane, and water, wherein the volume ratio of trifluoroacetic acid, triisopropylsilane, and water is 95:2-3:2-3. The anisole system comprises trifluoroacetic acid, water, anisole, and ethylenedithiol, wherein the volume ratio of trifluoroacetic acid, water, anisole, and ethylenedithiol is 90:5:2-3:2-3.
9. The method for preparing atosiban acetate according to claim 1, characterized in that, The volume fraction of the dimethyl sulfoxide aqueous solution in S5 is 3%-10%; The mass concentration of linear crude atosiban in the mixed solution was 0.01-0.03 g / mL; The oxygen flow rate is 0.1-0.5 L / min; The cyclization reaction is carried out at a temperature of 18-30℃ for a time of 40-90 minutes.
10. The method for preparing atosiban acetate according to claim 1, characterized in that, The microporous filter membrane described in S5 has a pore size of 0.22 μm; Reversed-phase HPLC purification was performed using a C18 column at a temperature of 25-35℃, with an acetonitrile-acetic acid aqueous solution as the mobile phase and a flow rate of 1.0-2.0 mL / min.