Methods for manufacturing peptide salts

Description

1 / 31 METHODS FOR MANUFACTURING PEPTIDE SALTS FIELD OF TECHNOLOGY

[001] The present invention relates to methods for preparing peptide salts, in particular pharmaceutically acceptable peptide salts, such as atosiban salts. The present invention further extends to the preparation of particles of such salts, such as by a spray drying process. The invention also relates to the peptide salts and particles of such salts that are produced by these methods. BACKGROUND

[002] Atosiban is a synthetic peptide that acts as an inhibitor of oxytocin and vasopressin. Atosiban is described in the literature as having several therapeutic uses, including as a tocolytic agent (e.g., to delay preterm labor and / or prevent premature labor). Atosiban comprises the following structure:

[003] Atosiban comprises a free base and can form acidic addition salts. For example, atosiban can form an acidic addition salt with acetic acid to give atosiban acetate. Atosiban acetate is marketed under the trade name Tractocile® for use in delaying preterm labor.

[004] Pamoic acid is an organic acid that can be used to form acidic addition salts. The chemical name of pamoic acid is 4,4'-methylene-bis(3-hydroxy-2-naphthoic acid). Its structure is shown below: Petition 870250088789, dated 09 / 30 / 2025, page 7 / 52 2 / 31

[005] Document No. CN114249800A (SHENZHEN SHENYIN PHARMACEUTICAL CO LTD) describes a method for preparing polypeptide pamoate salts. The method involves using a chromatographic column with a reversed-phase polymer load as a stationary phase. The column needs to be equilibrated before loading with a peptide solution, and subsequently, an aqueous solution of inorganic pamoic acid salt and an organic solvent is loaded onto the column in certain proportions to allow ion exchange to take place in the column. Document No. CN114249800A describes that its chromatographic method provides better control of impurities, ions, and / or solvent residues in the salts produced. SUMMARY

[006] The present invention is based on the finding that an atosiban pamoate salt can be prepared by a precipitation method. Surprisingly, the present inventors have identified that atosiban pamoate produced by the described precipitation methods yields compounds with a high degree of purity without the need for complex processing and / or purification steps. Such methods may be particularly likely to be scaled up for manufacturing.

[007] Thus, according to a first aspect, a method is provided for preparing an atosiban pamoate salt comprising: (i) bringing into contact and / or reacting a first atosiban salt and an inorganic pamoate salt, wherein atosiban pamoate is formed as a precipitate. Petition 870250088789, dated 09 / 30 / 2025, page 8 / 52 3 / 31

[008] The first atosiban salt may be any suitable atosiban salt that is soluble in a solvent in which atosiban pamoate is insoluble (e.g., under the temperature and pressure conditions in which the reaction occurs). The first atosiban salt is not atosiban pamoate. In some examples, the first atosiban salt may be a salt that has a solubility of at least 10 mg / ml at 25°C in aqueous solution. By way of representative example, the first atosiban salt may be selected from atosiban acetate, atosiban hydrochloride, and atosiban trifluoroacetate, or the like.

[009] By way of example, the method may comprise bringing into contact the first atosiban salt (e.g., atosiban acetate) and an inorganic pamoate salt under such conditions as to allow them to react. For example, the first atosiban salt (e.g., atosiban acetate) and an inorganic pamoate salt may be brought into contact and / or reacted in a reaction mixture (e.g., a suspension or a solution).

[0010] In particular, under the conditions as disclosed in this document, when the first atosiban salt (e.g., atosiban acetate) is brought into contact and / or reacted with an inorganic pamoate salt in a reaction mixture (e.g., a solution), an ion exchange reaction can occur, after which atosiban pamoate can be precipitated. Surprisingly, the inventors have identified that this precipitation method can provide atosiban pamoate salt products with a high degree of purity. This method for providing atosiban pamoate consequently offers greater ease of manufacture while maintaining good purity levels.

[0011] The solvents suitable for forming the reaction mixtures (e.g., solutions) that are used in the methods described in Petition 870250088789, dated 09 / 30 / 2025, page 9 / 52 4 / 31 of this document include aqueous solutions. In some examples, the solvent may be water, for example, deionized water. By way of another example, suitable solvents may include aqueous buffer solutions, such as sodium phosphate buffer, phosphate-buffered saline (PBS) buffer, Tris buffer (tris(hydroxymethyl)aminomethane buffer) and HEPES buffer (2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid) and the like.

[0012] In some examples, the method may include: (i) provide a solution of the first atosiban salt (e.g., atosiban acetate); and (ii) bring the solution of the first atosiban salt (e.g., atosiban acetate) into contact with an inorganic pamoate salt; in which atosiban pamoate is formed as a precipitate.

[0013] In some examples, the method further comprises preparing a solution of the first atosiban salt, for example, preparing a solution of atosiban acetate. For example, the solution of the first atosiban salt can be prepared by adding and / or dissolving the first atosiban salt in any suitable solvent. Suitable solvents for use in preparing solutions of the first atosiban salt include any of those described herein (e.g., aqueous solutions such as water (e.g., deionized water)). By way of another example, suitable solvents may include aqueous buffer solutions such as sodium phosphate buffer, phosphate-buffered saline (PBS) buffer, Tris buffer (tris(hydroxymethyl)aminomethane buffer) and HEPES buffer (2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid) and the like.

[0014] The concentration of the first atosiban salt (e.g., atosiban acetate) in the solution may be between about 0.05% and Petition 870250088789, dated 09 / 30 / 2025, page 10 / 52 5 / 31 w / v approximately 50% w / v, between approximately 0.1% w / v and approximately 20% w / v, between approximately 0.5% w / v and approximately 10% w / v, or between approximately 1% w / v and approximately 5% w / v. In some examples, the concentration of the first atosiban salt (e.g., atosiban acetate) in the solution may be between approximately 1.5% w / v and 4% w / v. In still other examples, the concentration of the first atosiban salt (e.g., atosiban acetate) in the solution may be approximately 2.5% w / v or approximately 3.3% w / v. References to concentration may refer to the concentration of the first atosiban salt (e.g., atosiban acetate) in a starting solution and / or to the concentration of the first atosiban salt (atosiban acetate) in the solution after the addition of the metal pamoate (e.g., if the volume has increased due to the addition of the inorganic pamoate in the form of a solution).

[0015] Inorganic pamoate salts useful in the methods described may include metallic pamoate salts. Examples of metallic pamoate salts that may be used in the methods described in this document include alkali metal and alkaline earth metal pamoate salts. Representative examples include, but are not limited to, sodium pamoate and potassium pamoate. In particular embodiments of the present invention, the metallic pamoate salt may be sodium pamoate.

[0016] The step of bringing the solution of the first atosiban salt (e.g., atosiban acetate) into contact with an inorganic pamoate salt (e.g., metallic) may involve adding the inorganic pamoate salt to the solution of the first atosiban salt. The inorganic pamoate salt may be added in the form of a solution or a suspension. By way of example, a solution of the inorganic pamoate salt may be prepared by adding and / or dissolving the inorganic pamoate in any suitable solvent. Petition 870250088789, dated 09 / 30 / 2025, page 11 / 52 6 / 31

[0017] Suitable solvents for use in the preparation of solutions of inorganic pamoate salt include aqueous solutions. In some examples, the solvent may be water, for example, deionized water. By way of another example, suitable solvents may include aqueous buffer solutions, such as sodium phosphate buffer, phosphate-buffered saline (PBS) buffer, Tris buffer (tris(hydroxymethyl)aminomethane buffer) and HEPES buffer (2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid) and the like.

[0018] The concentration of inorganic pamoate salt in the solution may be between about 0.01% w / v and about 50% w / v, between about 0.05% w / v and about 20% w / v, between about 0.1% w / v and about 10% w / v, or between about 0.25% w / v and about 5% w / v. In some examples, the concentration of inorganic pamoate salt in the solution may be between about 0.5% w / v and 4% w / v. In still other examples, the concentration of inorganic pamoate salt in the solution may be about 2.3% w / v or about 0.6% w / v.

[0019] References to concentration may refer to the concentration of inorganic pamoate in a starting solution and / or to the concentration of inorganic pamoate in the final solution after addition to the solution of the first atosiban salt.

[0020] The molar ratio between the first atosiban salt (e.g., atosiban acetate) and the inorganic pamoate used, brought into contact and / or reacted in the reaction may be anywhere between about 10:1 and about 1:10, as between about 5:1 and about 1:5 or between 3:1 and 1:3. In some examples, the molar ratio between the first atosiban salt and the inorganic pamoate used, brought into contact and / or reacted in the reaction may be anywhere between about 2.5:1 and about 1:1, for example, about 2.1:1 and about 1.1:1.

[0021] In some examples, a solution of the inert pamoate salt Petition 870250088789, dated 09 / 30 / 2025, p. 12 / 52 7 / 31 organic (e.g., an aqueous solution of sodium pamoate) can be added to the solution of the first atosiban salt in portions and / or incrementally. As another example, the solution of the inorganic pamoate salt can be added dropwise to the solution of the first atosiban salt.

[0022] During the addition of the inorganic pamoate salt (which may optionally be added in the form of a solution as presented above), the resulting reaction mixture may be stirred, for example, continuously stirred to help facilitate and / or promote the ion exchange reaction.

[0023] The method can proceed under any conditions suitable to facilitate and / or promote ion exchange and / or precipitation of atosiban pamoate from the reaction mixture (e.g., solution). The method can be conducted under ambient conditions. For example, the method can be conducted at room temperature and / or under atmospheric pressure.

[0024] In some cases, the method can be run at temperatures above about 0°C, above about 10°C, or above about 15°C. In some cases, the method can be run at a temperature between about 0°C and about 100°C. For example, the method can be run at a temperature between about 10°C and about 50°C or between about 15°C and about 35°C. In some cases, the method can be run at around room temperature (for example, at a temperature between about 18°C ​​and about 27°C or between about 20°C and about 25°C).

[0025] In some cases, the method can be performed under atmospheric pressure. For example, at a pressure in the region of 101,325 kPa or 1 atmosphere.

[0026] Suitable solvents for the freeze-drying step can be any solvent in which atosi pamoate Petition 870250088789, dated 09 / 30 / 2025, p. 13 / 52 8 / 31 bano has a solubility of at least 20 mg / ml (e.g., at 25°C). Preferably, the solvents for the freeze-drying step may also have a melting point of at least 80°C. Suitable solvents for the freeze-drying step may comprise mixtures of acetonitrile and water. By way of representative example, the solvent for the freeze-drying step may be or comprise a mixture of acetonitrile and water at a ratio of 1:10 to 10:1 (v / v) (e.g., in a mixture of acetonitrile / water (1 / 2, v / v)).

[0027] According to a further aspect, an atosiban pamoate salt produced according to the methods described in this document is provided. In particular, using the methods described in this document, the present inventors have identified that a specific form of atosiban pamoate salt can be obtained. In particular, in some examples, the atosiban pamoate salts provided by the methods of the present invention may be a semisalt.

[0028] Thus, according to a further aspect of the present invention, an atosiban pamoate salt is provided in which the molar ratio between atosiban and pamoate in the salt is about 2:1.

[0029] Atosiban pamoate salts with the stoichiometries described in this document may allow higher drug loadings than a monosalt form, which may help reduce formulation volumes when the salts are formulated for pharmaceutical uses (and which may, in turn, help increase patient adherence in the clinic).

[0030] In some instances, it may be desirable to provide atosiban pamoate in particulate form (e.g., as particles). For example, injectable formulations generally require particles of an appropriate and / or uniform size. One option for Petition 870250088789, dated 09 / 30 / 2025, page 14 / 52 9 / 31 To remove such particles is through the use of a spray drying technique.

[0031] Thus, the methods described in this document may also include a spray drying step of atosiban pamoate to provide atosiban pamoate particles.

[0032] Thus, according to a further aspect of the invention, a method is provided for supplying atosiban pamoate particles comprising: (i) provide an atosiban pamoate loading solution; and (ii) spray dry the loading solution to form atosiban pamoate particles.

[0033] As used in this document, spray drying can refer to a process in which a dry powder (e.g., containing a compound) is formed from a liquid. The spray drying process typically involves atomizing a solution (referred to in this document as a loading solution) by spraying followed by rapid evaporation of the sprayed droplets onto solid powders by a hot gas.

[0034] For a spray drying process to be effective, several factors need to be balanced. One such factor is the identification of a suitable loading solution for the compound to be spray dried. The loading solution should preferably be volatile at temperatures at which the compound in question remains stable. The compound in question must show reasonable solubility in the solvent and also a good level of stability in the spray drying process. The latter point can be particularly important when compounds are to be manufactured on an industrial scale, for example, when compounds may be saturated in Petition 870250088789, dated 09 / 30 / 2025, page 15 / 52 10 / 31 solution for longer periods of time before a spray drying step. The need for stability becomes more significant for compounds (such as atosiban pamoate) intended for use in pharmaceutical formulations, where purity is highly important. Furthermore, the use of this loading solution in the spray drying process itself should preferably produce particles of suitable and / or uniform size with good appearance and syringeability properties (e.g., when the particles are intended for use in an injectable formulation).

[0035] Difficulties were encountered in identifying a suitable loading solution for use in spray drying atosiban pamoate, for example, a loading solution for this particular compound that could provide at least acceptable levels of solubility while also balancing the need to maintain good levels of stability in the loading solution. In other words, a loading solution that could be compatible with atosiban pamoate to provide a reproducible and reliable spray drying process that could be susceptible to manufacturing scale-up.

[0036] In particular, a cohort of loading solutions was identified in which atosiban pamoate can show good levels of solubility and stability. The loading solutions may also show suitable volatilities for spray drying of atosiban pamoate and / or may be used to provide particles of suitable and / or uniform size (e.g., for therapeutic applications).

[0037] In particular, atosiban pamoate may have a solubility in the loading solution of at least about 15 mg / ml, at least about 20 mg / ml, or at least about 25 mg / ml. In Petition 870250088789, dated 09 / 30 / 2025, page 16 / 52 11 / 31 For some examples, atosiban pamoate may have a solubility in the loading solution between about 15 mg / ml and 100 mg / ml, between about 20 mg / ml and 75 mg / ml, or between about 20 mg / ml and 60 mg / ml. As described in this document, solubility is measured at room temperature and under atmospheric pressure.

[0038] Atosiban pamoate can show good levels of stability in the loading solution (e.g., when stored in the loading solution before a spray drying step).

[0039] As used in this document, the expression "good levels of stability" may mean that the atosiban pamoate present in the loading solutions, as described in the present invention, is substantially stable and / or exhibits minimal or no degradation.

[0040] In particular, atosiban pamoate may be substantially stable and / or exhibit minimal or no degradation in the disclosed loading solutions when stored for a period of at least 1 hour, at least 2 hours, at least 3 hours, or at least 4 hours. In other examples, atosiban pamoate may be substantially stable and / or exhibit minimal or no degradation in the disclosed loading solutions when stored for a period of at least 12 hours, at least 24 hours, at least 36 hours, or at least 48 hours. In other examples, atosiban pamoate may be substantially stable and / or exhibit minimal or no degradation in the disclosed loading solutions when stored for a period of at least 1 day, at least 2 days, at least 3 days, or at least 4 days. In these examples, the loading solutions may be stored at room temperature or under refrigeration conditions.In particular, charging solutions can be stored at temperature. Petition 870250088789, dated 09 / 30 / 2025, p. 17 / 52 12 / 31 ambient (for example, at a temperature between about 15°C and about 30°C, as between about 20°C and about 25°C) and / or under atmospheric pressure.

[0041] As used in this document, stable may mean that atosiban pamoate can retain at least about 98.9%, at least about 99.0%, at least about 99.1%, at least about 99.2%, at least about 99.3%, at least about 99.4%, or at least about 99.5% of an original purity level when stored in the loading solution.

[0042] Loading solutions may exhibit suitable levels of volatility for spray drying of atosiban pamoate. In some examples, loading solutions may have a boiling point less than or equal to about 150°C, less than or equal to about 125°C, or less than or equal to about 100°C.

[0043] The step of providing an atosiban pamoate loading solution may comprise preparing an atosiban pamoate loading solution. For example, the atosiban pamoate loading solution may be prepared by adding and / or dissolving atosiban pamoate in any suitable solvent as described herein.

[0044] In some examples, the loading solution may comprise one or more solvents, for example, two, three, or four solvents. In some cases, the loading solution may comprise two solvents.

[0045] One or more solvents may be selected from alcohol, water, and acetonitrile. The alcohol may be a saturated or unsaturated alcohol. Branched-chain or straight-chain alcohols may be used. Suitable alcohols include, but are not limited to, C1-C6 alcohols or C1-C4 alcohols. Representative examples of suitable alcohols (but are not limited to) are methanol, ethanol, isopropanol, n-propanol, isobutyl alcohol. Petition 870250088789, dated 09 / 30 / 2025, page 18 / 52 13 / 31 nol, sec-butanol, tert-butanol, pentanol and hexanol.

[0046] In some examples, the loading solution may comprise an alcohol (e.g., methanol).

[0047] In particular, the charging solution may comprise an alcohol and water. By way of further example, the charging solution may comprise methanol and water, or ethanol and water.

[0048] In other examples, the loading solution may comprise acetonitrile and water.

[0049] In particular, in some examples, the loading solution may comprise a solvent system selected from: (i) an alcohol (e.g., a C1-C4 alcohol, such as methanol); (ii) an alcohol (e.g., a C1-C4 alcohol, such as methanol) and water; and (iii) acetonitrile and water. In particular, the inventors have identified that such solvent systems can be used to provide effective loading solutions for atosiban pamoate, to provide good levels of both solubility and volatility, while maintaining the good levels of stability of atosiban pamoate. In still other examples, the loading solution may comprise a solvent system selected from: (i) an alcohol (such as methanol) and water; and (ii) acetonitrile and water.

[0050] When two or more solvents are present in the loading solution, they may be present in any suitable ratio that provides adequate levels of volatility, solubility and / or stability of atosiban pamoate. In some examples, when two solvents are present, they may be present in a ratio (volume of a first solvent:volume of a second solvent) between about 100:1 to about 1:100, between about 10:1 to about 1:10 or between about 1:5 and about 5:1.

[0051] As a further example, when the loading solution comprises an alcohol (e.g. C1-C4 alcohol, as per Petition 870250088789, dated 09 / 30 / 2025, page 19 / 52 14 / 31 ethanol) and water, the two solvents may be present in a ratio between about 10:1 and about 1:10 of alcohol (e.g., C1-C4 alcohol, such as methanol):water volume. In some examples, the loading solution may comprise any ratio between about 1:1 and about 10:1, or between about 2:1 and about 8:1, or between about 3:1 and 7:1 of alcohol (e.g., C1-C4 alcohol, such as methanol):water (v / v). In some examples, the loading solution may comprise approximately 5:1 of alcohol (e.g., C1C4 alcohol, such as methanol):water (v / v).

[0052] By way of yet another representative example, when the loading solution comprises acetonitrile and water, the two solvents may be present in a ratio between about 10:1 and about 1:10 of acetonitrile volume:water volume. In some examples, the loading solution may comprise any ratio between about 1:1 and about 10:1, or between about 1:1 and about 5:1, or between about 2:1 and about 4:1 of acetonitrile:water (v / v). In some examples, the loading solution may comprise approximately 3:1 of acetonitrile:water (v / v).

[0053] As stated previously, the method comprises a spray-drying step of the disclosed loading solutions to form atosiban pamoate particles (sometimes referred to herein as spray-dried atosiban pamoate particles).

[0054] The spray drying step can be performed using any of the spray drying systems known in the art.

[0055] Spray dryers typically include a drying chamber into which the liquid feed (e.g., the loading solution, as described above) is introduced through an inlet. This inlet generally takes the form of a Petition 870250088789, dated 09 / 30 / 2025, page 20 / 52 15 / 31 atomizer. A drying gas is also introduced into the drying chamber, which causes the loading solution to evaporate, leaving behind solid particles (e.g., atosiban pamoate solid particles). These solid particles can typically be separated using a particle separator (such as a cyclone) and collected in a vessel. An overview of the spray drying process in the pharmaceutical industry can be found in Gaspar et al., European Pharmaceutical Review, October 28, 2014, Spray drying in the pharmaceutical industry. As a representative example, the spray drying step can be performed by a Mini Spray Dryer B-290 (Buchi, Switzerland).

[0056] In some examples, during the spray drying stage, the inlet temperature (e.g., the temperature of the drying air at the inlet to the drying chamber) may be between about 50°C and about 150°C, between about 75°C and about 125°C, between about 90°C and about 110°C, or between about 95°C and about 105°C. In some examples, the inlet temperature may be around 100°C.

[0057] In some examples, during the spray drying stage, the feed rate (e.g., the rate at which the loading solution is introduced into the atomizer before entering the drying chamber) may be between about 0.5 ml / min and about 20 ml / min, between about 1 and 10 ml / min, or between about 2 and 7 ml / min. In some examples, the feed rate may be between about 3 ml / min and about 6 ml / min. In still other examples, the feed rate may be about 4 ml / min.

[0058] In some examples, during the spray drying stage, the atomizing gas flow rate (e.g., the rate at which atomizing gas is introduced into the atomizer) can provide a height reading on the gas flowmeter between about 10 and about Petition 870250088789, dated 09 / 30 / 2025, page 21 / 52 16 / 31 of 100 mm, between about 25 mm and 75 mm or between about 30 mm and 50 mm. In some examples, the atomizing gas flow rate may be about 40 mm. As used in this document, mm is the unit of height as a reading on the gas flowmeter. The unit of height can be converted to actual atomizing gas volume flow rate under standard temperature and pressure conditions. As an example, a height of 40 mm may correspond to an actual gas volume flow rate of 667 l / h. Consequently, in some examples, the atomizing gas flow rate may be between about 283 l / h and about 1744 l / h, between about 355 l / h and about 1374 l / h or between about 439 l / h and about 1052 l / h.

[0059] In some examples, during the spray drying stage, the drying gas flow rate (e.g., the flow rate at which the drying gas is introduced into the drying chamber) may be between about 1 m3 / h and about 100 m3 / h, between about 10 m3 / h and about 75 m3 / h, between about 20 m3 / h and 50 m3 / h. In some examples, the drying gas flow rate may be about 35 m3 / h.

[0060] Atosiban pamoate particles produced by the spray-drying process may comprise a substantially spherical or nearly spherical shape. Spray-dried atosiban pamoate particles produced by the methods (and with the use of loading solutions) described herein may comprise diameters between about 0.1 and about 50 μm (microns), as well as between about 0.5 μm and about 25 μm or between about 1 μm and 10 μm. In particular, spray-dried atosiban pamoate particles produced by the methods (and with the use of loading solutions) described herein may comprise diameters between about 1 μm and 8 μm. Spray-dried atosiban pamoate particles, as described herein Petition 870250088789, dated 09 / 30 / 2025, page 22 / 52 17 / 31 document, may find particular application in injectable formulations.

[0061] After the spray drying step, the purity of atosiban pamoate present in the particles can be at least about 90%, at least about 95%, at least about 97% or at least about 99% (based on the total weight of the particles).

[0062] According to another aspect of the present invention, atosiban pamoate particles obtainable by the methods described in this document are also provided.

[0063] A loading solution comprising atosiban pamoate is also provided in any of the loading solutions described in this document.

[0064] By particular example, a loading solution is provided for a spray drying process comprising atosiban pamoate and a solvent system selected from: (i) approximately 5:1 alcohol (for example, a C1-C4 alcohol, such as methanol):water (v / v); and (ii) approximately 3:1 acetonitrile:water (v / v).

[0065] The methods described in this document may find particular application in the preparation of atosiban pamoate for use in pharmaceutical compositions. Such pharmaceutical compositions may comprise atosiban pamoate together with one or more additional carrier ingredients, such as diluents, excipients, buffers, flavoring agents, binders, surface-active agents, thickeners, lubricants, preservatives (including antioxidants) and the like. Definitions

[0066] In the present invention, reference is made to various terms, which should be understood as having the meanings given below, unless the context indicates otherwise. The nomenclature Petition 870250088789, dated 09 / 30 / 2025, page 23 / 52 The definition 18 / 31 used in this document to define compounds, in particular the compounds described herein, must conform to the rules of the International Union of Pure and Applied Chemistry (IUPAC) for chemical compounds, specifically the IUPAC Compendium of Chemical Terminology (Gold Book) (see AD Jenkins et al., Pure & Appl. Chem., 68, 2287-2311 (1996)). For the sake of clarity, if an IUPAC rule contradicts a definition provided in this document, the definition in this document shall prevail.

[0067] As used in this document, the term about, when qualifying a number or value, may refer to values ​​that are within ± 5% of the specified value. For example, when a particle is described as having a diameter of about 50 μm, a range of 47.5 μm to 52.5 μm is included.

[0068] Additionally, as used in this document, when any range is described as being between a lower limit and an upper limit, the defined range includes the defined endpoints (and thus includes both the lower limit and upper limit values). Isotopically identified compounds

[0069] The invention also encompasses various deuterated forms of atosiban pamoate and any other compounds as described herein. Each available hydrogen atom bonded to a carbon atom can be independently replaced by a deuterium atom. A person of ordinary skill in the art will know how to synthesize deuterated forms of the compounds described herein, including those mentioned above. For example, deuterated materials, such as alkyl groups, can be prepared by conventional techniques (see, for example, methyl-d3-amine available from Aldrich Chemical Co., Milwaukee, WI, Petition 870250088789, dated 09 / 30 / 2025, p. 24 / 52 19 / 31 n° Cat. 489.689-2).

[0070] The invention also includes isotopically identified compounds of the present invention, but in that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number most commonly found in nature. Examples of isotopes that can be incorporated into the compounds of the invention include isotopes of hydrogen, carbon, nitrogen, oxygen, fluorine, iodine, and chlorine such as 3H, 11C, 14C, 18F, 123I, or 125I. The compounds of the present invention and pharmaceutically acceptable salts of said compounds containing the aforementioned isotopes and / or other isotopes of other atoms are within the scope of the present invention. The isotopically identified compounds of the present invention, for example, those in which radioactive isotopes such as 3H or 14C have been incorporated, are useful in tissue distribution assays of substrate and / or drug.The titrated isotopes, i.e., 3H and carbon-14, i.e., 14C, are particularly preferred for their ease of preparation and detectability. The isotopes 11C and 18F are particularly useful in PET (positron emission tomography).

[0071] It should be noted that, throughout this descriptive report, the term "comprising" is used to denote that embodiments of the invention comprise the indicated features and, in this way, may also include other features. However, in the context of this invention, the term "comprising" may also encompass embodiments in which the invention essentially consists of the relevant features or consists of the relevant features. DETAILED DESCRIPTION

[0072] The present invention will be further described below with reference to the following non-limiting examples.

[0073] Figure 1: 1H NMR spectrum of atosiban acetate. Petition 870250088789, dated 09 / 30 / 2025, p. 25 / 52 20 / 31

[0074] Figure 2: 1H NMR spectrum of atosiban pamoate produced according to an exemplary method of the invention.

[0075] Figure 3: UPLC assay of atosiban pamoate powder produced by an exemplary method of the invention.

[0076] Figure 4: UPLC assay of spray-dried atosiban pamoate particles using an exemplary spray-drying method of the invention.

[0077] Figure 5: Scanning electron microscopy (SEM) images of lyophilized atosiban pamoate (Left (500x), Right (1000x)).

[0078] Figure 6: Scanning electron microscopy (SEM) images of spray-dried atosiban pamoate particles (Left (3000x), Right (5500x)). PART A: Chemistry - Materials and Methods

[0079] All chemicals, unless otherwise indicated, were commercially available and used without further purification. NMR analysis

[0080] NMR data were acquired on a Bruker Avance NEO 400 MHz NMR spectrometer (Bruker, USA). The chemical shift is reported in ppm relative to dimethyl sulfoxide (δ 2.50) as indicated in the NMR spectral data. For sample preparation, a small amount (1-5 mg) of sample (atosiban acetate or atosiban pamoate) was dissolved in DMSO-d6 (0.6 ml) and transferred to the test tube for NMR analysis. All experiments were performed at a temperature of 25°C. Analysis by Ultra-Performance Liquid Chromatography (UPLC)

[0081] The UPLC was performed on a Waters Acquity Class H UPLC system (Waters, USA) equipped with a Waters Ac UPLC Petition 870250088789, dated 09 / 30 / 2025, page 26 / 52 21 / 31 quity®BEH Phenyl 1.7 μm, 2.1 x 100 mm column. UPLC parameters are listed below: Description Parameter UPLC Column Waters Acquity® BEH Phenyl 1.7 μm, Mobile Phase A 2.1 x 100 mm 0.1% TFA (trifluoroacetic acid) in H2O Mobile Phase B 0.1% TFA in ACN (acetonitrile) Detection 210 nm (bandwidth 4 nm); sample collection Flow rate spectra 190-400 nm 0.3 ml / min Injection volume 3 pl Temp. Column temperature 30°C Auto-sampler temperature 5°C Round time 10 min Needle Wash 0.1% TFA in water / ACN (90:10)

[0082] The UPLC mobile phase gradient was as follows: Time (min) % Mobile Phase B 0 30 3 30 7 90 7.01 30 10 30 Scanning Electron Microscopy (SEM) Analysis:

[0083] SEM was performed on a Phenom™ Pure transmission electron microscope (Thermo Fisher Scientific, USA). For sample preparation, spray-dried powder was dispersed directly onto the carbon adhesive, and excess powder was removed by blowing a jet of particle-free compressed gas onto each, followed by coating with gold platinum under high vacuum. SEM images were digitally recorded at the highest magnification. Particle sizes were determined by examining the micrographs. Petition 870250088789, dated 09 / 30 / 2025, page 27 / 52 22 / 31 graphs using the independent measuring tool. A.1 Preparation of atosiban pamoate

[0084] Atosiban pamoate salt was prepared by a precipitation method. 5 g of atosiban acetate (94.5% free base, MW=994.5 Da) were dissolved in 150 ml of deionized water (DI). Separately, 1.15 g of sodium pamoate (Na2Pamoate; MW=432.34 Da, 1.1 molar ratio of acid to base) was dissolved in 50 ml of deionized water (DI). The mixture was made by adding atosiban acetate solution to sodium pamoate solution dropwise under continuous stirring with a stirrer suspended in a 500 ml beaker at room temperature. Precipitates formed during continuous stirring, and stirring continued for a further 4 hours at room temperature. The gelatin-like precipitate was quickly rinsed twice with deionized water (DI) and redissolved in an acetonitrile / water mixture (1 / 2, v / v).Finally, the redissolved atosiban pamoate solution was pre-frozen at -40°C for 24 hours, then placed in a freeze dryer for 72 hours to obtain atosiban pamoate in powder form.

[0085] To confirm the successful synthesis of atosiban pamoate, 1H NMR and UPLC were used to analyze the synthesized product. Equilibrium solubility studies were performed to verify the change in the solubility of atosiban in aqueous medium after the exchange of hydrophobic ions.

[0086] The stoichiometry of the atosiban:acetate starting material was determined to be approximately 0.93:1 by 1H NMR (DMSO-1), indicating that atosiban acetate was a monoacetate salt (see Figure 1).

[0087] The stoichiometry of atosiban:pamoate was determined to be 1:0.5 by 1H NMR (DMSO-d6) (see Figure 2). The acetate signal was not found, suggesting that a pamoate salt of Petition 870250088789, dated 09 / 30 / 2025, page 28 / 52 23 / 31 atosibano, as semipamoato, was formed.

[0088] Figure 3 shows UPLC graphs of atosiban acetate (upper curve) and atosiban pamoate (lower curve). The UPLC analysis was performed according to the method presented in the Materials and Methods section and indicates that the purity of atosiban pamoate is almost 100%. (Note that in the atosiban pamoate UPLC curve, the peak at ~2.6 min is for atosiban free base, while the peak at ~6.6 min is for pamoic acid. In contrast, there is only a peak for atosiban free base at ~2.6 min in the atosiban acetate curve, since acetic acid has no peak under the experimental condition). A.2 Equilibrium solubility studies:

[0089] The results of equilibrium solubility studies of atosiban acetate and atosiban pamoate in phosphate-buffered saline (PBS) are shown in Table 1 below. Table 1 Type of Salt 8 h 24 h 48 h S pH S pH S pH Acetate > 59.84 6.41 > 58.62 6.37 > 51.34 6.35 > 61.02 6.41 > 58.40 6.39 > 50.92 6.34 Pamoate 3.10 7.12 5.45 7.08 7.90 7.03 2.89 7.10 5.46 7.12 7.77 7.06

[0090] Table 1 shows equilibrium solubility results of atosiban acetate and atosiban pamoate in phosphate-buffered saline (PBS). S: solubility (mg / ml), solubility was calculated on a free basis.

[0091] The approximate solubility of atosiban acetate in PBS solution (pH = 7.4) at room temperature (~25 °C) was above 197 mg / ml. Atosiban acetate showed high solubility (> 60 mg / ml), where the solution became clear after stirring at 37 °C for 8 hours and remained clear within 48 hours. In comparison, the Petition 870250088789, dated 09 / 30 / 2025, page 29 / 52 24 / 31 pamoate salt showed solubility (~7.8 mg / ml, average value) in PBS solution at 37 °C within 48 hours. Additionally, a gel was observed at the bottom after stirring for 8 hours. The result indicated that pamoate salt showed significantly lower solubility than atosiban acetate in PBS. PART B: Spray drying of atosiban pamoate

[0092] Gelation of atosiban pamoate was observed in certain solvent systems typically used in a spray drying process, indicating that they would be unsuitable for use in spray drying atosiban pamoate. The inventors conducted further investigations to identify a suitable solvent to provide a loading solution for the spray drying step. B1: Initial solubility studies

[0093] The approximate solubility of atosiban pamoate was determined at room temperature and under atmospheric pressure.

[0094] A visual inspection solubility screening method was used to measure approximate solubilities according to the following procedure: 1. Approximately 2 mg of atosiban pamoate salt powder were weighed into each of the 2 ml vials; 2. For each group, the tested solvent was added sequentially according to the following steps: Step 1: 50 μl of solvent were added to the flask. If the salt dissolved, the data for Solubility were calculated as (S)>40 mg / ml (the actual S was calculated on a case-by-case basis using the equation: S=actual weight / 0.05); If the salt did not dissolve, the tester continued to Step 2; Step 2: 50 μl of solvent were added to the flask. If the salt dissolved, the solubility data were calculated as... Petition 870250088789, dated 09 / 30 / 2025, page 30 / 52 25 / 31 40>S>20 mg / ml (the actual S value was calculated on a case-by-case basis); If the salt did not dissolve, the tester proceeded to Step 3; Step 3: 100 μl of solvent were added to the flask. If the salt dissolved, the solubility data was calculated as 20 > S > 10 mg / ml (the actual S was calculated on a case-by-case basis); If the salt did not dissolve, the tester proceeded to Step 4; Step 4: 200 μl of solvent were added to the flask. If the salt dissolved, the solubility data was calculated as 10 > S > 5 mg / ml (the actual S was calculated on a case-by-case basis); If the salt did not dissolve, the tester continued to Step 5; Step 5: 200 μl of solvent were added to the flask. If the salt dissolved, the solubility data was calculated as 5>S>3.33 mg / ml (the actual S was calculated on a case-by-case basis); If the salt did not dissolve, the tester proceeded to Step 6; Step 6: 400 μl of solvent were added to the flask. If the salt dissolved, the solubility data was calculated as 3.33 > S > 2 mg / ml (the actual S was calculated on a case-by-case basis); if the salt did not dissolve, S < 2 mg / ml (the actual S must be calculated on a case-by-case basis).

[0095] The results of the initial solubility studies in pure volatile solvents are described in Table 2 below. Table 2 Solvent Solubility (mg / ml) H2O (Water) S<2.4 Acetonitrile S<2.0 EtOAc (Ethyl acetate) S<2.1 DCM (Dichloromethane) S<2.6 THF (Tetrahydrofuran) S<2.0 Acetone S<2.1 MeOH (Methanol) 23 <S<46 EtOH (Etanol) S<1,9

[0096] Table 2 shows the results of initial studies of Petition 870250088789, dated 09 / 30 / 2025, page 31 / 52 26 / 31 Lubricability of atosiban pamoate in pure volatile solvents.

[0097] The limited solubility of atosiban pamoate was observed in almost all pure volatile solvents tested (with the exception of methanol). Consequently, the inventors conducted some further investigations into the solubility of atosiban pamoate in various water-based and organic solvent mixtures. The results are shown in Table 3 below. Table 3 Solvent (v / v) Solubility (mg / ml) Solvent (v / v) Solubility (mg / ml) Acetonitrile: H2O (1:2) S>45 MeOH: H2O (1:2) 2.3 <S<3,8 Acetonitrila: H2O (1:1) S> 50 MeOH: H2O (1:1) 21 <S<42 Acetonitrila: H2O (2:1) S> 46 MeOH: H2O (2:1) S>58 THF: H2O (1:2) S>54 EtOH: H2O (1:2) 22 <S<43 THF: H2O (1:1) S> 39 EtOH: H2O (1:1) S>50 THF: H2O (2:1) S>47 EtOH: H2O (2:1) 22 <S<43 Acetona: H2O (1:2) S> 43 Acetone: H2O (1:1) S>45 Acetone: H2O (2:1) S>41

[0098] Table 3 shows the results of initial solubility studies of atosiban pamoate in various mixed solvent systems.

[0099] These initial solubility investigations highlighted several possible solvent systems that provided good and / or acceptable levels of solubility for atosiban pamoate. B2: Short-term stability studies

[00100] The inventors then conducted further investigations into the short-term stability of atosiban pamoate to confirm its compatibility with different solvent systems. Stability studies were performed at 25°C and under atmospheric pressure. UPLC was used to determine the purity of Petition 870250088789, dated 09 / 30 / 2025, page 32 / 52 27 / 31 atosiban pamoate at various time points after atosiban pamoate was added to the solvent system (0 minutes, 4 hours, 24 hours, and 4 days). The change in the free base peak area ratio of atosiban (atosiban purity) at various time points was summarized to assess the short-term stability of atosiban pamoate. (The UPLC measurement methods used in this study are summarized in the Materials and Methods section).

[00101] The results are shown in Table 4. Table 4 Solvent system (v / v) Atosiban pamoate purity (%) 0 min 4 h 24 h 4 d MeOH 99.85% 99.91% 99.81% 99.88% Acetonitrile: H2O (2:1) 99.86% 99.90% 99.80% 99.96% THF: H2O (2:1) 99.26% 99.16% 98.51% 98.81%, obvious impurity peaks Acetone: H2O (2:1) 99.90% 99.75% 99.51% 97.80%, obvious impurity peaks MeOH: H2O (2:1) 99.92% 99.83% 99.74% 99.56% EtOH: H2O (2:1) 99.88% 99.95% 99.87% 99.38%

[00102] Table 4 shows the results of short-term stability studies performed on atosiban pamoate in different solvent systems at 0 h, 4 h, 24 hours and 4 days after the addition of atosiban pamoate to the solvent system.

[00103] Short-term stability data revealed that THF and acetone can lead to the degradation of atosiban peptide under certain conditions, while acetonitrile, MeOH, and EtOH had good compatibility with atosiban pamoate and were suitable for use in the spray drying process. B3: Development of a spray drying process:

[00104] After initial investigations into suitable solvents Petition 870250088789, dated 09 / 30 / 2025, page 33 / 52 28 / 31 for use in the loading solution, other parameters of the spray drying process were investigated, including solvent, inlet temperature, and feed rate. The atomizing gas flow rate (40 mm) and the drying gas flow rate (35 m³ / h) were kept constant during the process development. Regarding the atomizing gas flow rate, note that 40 mm represents the height reading on the gas flowmeter. This number can be converted into the actual atomizing gas volume flow rate under standard temperature and pressure conditions. For example, a height of 40 mm is equal to an actual gas volume flow rate of 667 l / h.

[00105] Several attributes of spray-dried products were then analyzed, including purity, assay and syringeability.

[00106] In particular, six batches of spray-drying manufacturing processes at a scale of 300 mg were conducted. The results are shown in Table 5 below. Table 5 Lot No. Solvent (V:V) Inlet Temperature (°C) Feed Rate (ml / min n) Solid Concentration (%) Appearance Syringability Purity (%) Assay (%) 1 ACN / H2O (3:1) 100 5.5 3 Product Not dry Good ~100 79.9 2 ACN / H2O (3:1) 110 6.3 3 Good Acceptable 69.06 ND 3 MeOH / H2O (5:1) 100 5.5 3 Good Good ~100 81.3 Petition 870250088789, dated 09 / 30 / 2025, page 34 / 52 29 / 31 Lot No. Solvent (V:V) Inlet Temperature (°C) Feed Rate (ml / min) Solid Concentration (%) Appearance Syringability Purity (%) Assay (%) 4 MeOH 90 5 3 Low product density Poor ~100 81.3 5 ACN / H2O (3:1) 105 1.9 3 Good Acceptable ~100 81.0 6 MeOH / H2O (5:1) 100 3.1 3 Good Good ~100 81.6

[00107] Table 5 shows the results of investigations in the pro- spray drying process of atosiban pamoate.

[00108] In Table 5, purity is based on the change in peak area ratio of atosiban free base (as determined by UPLC analysis), indicating the degree of degradation of atosiban free base in atosiban pamoate salt, for example, ~100% purity indicates that there is substantially no degradation to atosiban free base in atosiban pamoate salt, indicating good stability during processing. In Table 5, assay % data indicate the atosiban free base content in atosiban pamoate powder. The assay % in the final atosiban pamoate particles is around 80% due to the presence of pamoic acid in atosiban pamoate. B4: Spray-dried atosiban pamoate particles B4.1: Method:

[00109] A spray drying method was used to manufacture atosiban pamoate particles. Lyophilized atosiban pamoate powder (1.2 g) was dissolved in a MeOH / H2O mixed solvent (40 ml, 5:1, v / v). The solution was filtered through a 0.22 filter. Petition 870250088789, dated 09 / 30 / 2025, page 35 / 52 30 / 31 μm and spray dried using a Mini Spray Dryer B-290 (Buchi, Switzerland) at an inlet temperature of 100°C and a feed rate of 4.0 ml / min. The atomizing gas flow rate and the drying gas flow rate were maintained at 40 mm and 35 m³ / h, respectively. B4.2: Analysis:

[00110] Spray-dried atosiban pamoate particles produced according to the method presented in B4:1 were characterized by Ultra-Performance Liquid Chromatography (UPLC) and Scanning Electron Microscopy (SEM) (according to the methods presented in the Materials and Methods section). The results are shown in Figures 4, 5, and 6.

[00111] Referring to Figure 4, the UPLC analysis of atosiban acetate (upper curve) and spray-dried atosiban pamoate particles (lower curve). The UPLC analysis indicated that the purity of the spray-dried atosiban pamoate powders was almost 100%. (Again, it is observed that in the atosiban pamoate UPLC curve, the peak at ~2.6 min is for atosiban free base, while the peak at ~6.6 min is for pamoic acid. In contrast, there is only a peak for atosiban free base at ~2.6 min in the atosiban acetate curve, since acetic acid has no peak under the experimental condition).

[00112] SEM analysis of spray-dried atosiban pamoate particles (produced according to the procedure presented in B4.1: Method above) showed that these particles had a spherical or nearly spherical shape with diameters approximately between 1 and 8 μm (see SEM images in Figure 6). Such particles are considered suitable for use in injectable formulations. In contrast, SEM analysis of lyophilized atosiban pamoate powder showed that the particles had a Petition 870250088789, dated 09 / 30 / 2025, page 36 / 52 31 / 31 irregular sheet format with generally larger particle sizes (in the range between 20 μm and 80 μm in diameter) (see SEM images in Figure 5). These were considered less suitable for use in injectable formulations.

[00113] Although the present invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, the descriptions and examples should not be interpreted as limiting the scope of the invention. The disclosures of all patents and scientific literature mentioned in this document are expressly incorporated herein in their entirety by way of reference. Petition 870250088789, dated 09 / 30 / 2025, p. 37 / 52

Claims

1 / 4 CLAIMS 1. Method for preparing atosiban pamoate, characterized by comprising: (i) bringing into contact and / or reacting a first atosiban salt and an inorganic pamoate salt in a reaction mixture, wherein atosiban pamoate is formed as a precipitate.

2. Method according to claim 1, characterized in that the first atosiban salt is an atosiban salt having a solubility of at least 10 mg / ml at 25 °C in aqueous solution and / or in that the first atosiban salt is selected from atosiban acetate, atosiban hydrochloride and atosiban trifluoroacetate.

3. Method according to claim 1 or 2, characterized in that the inorganic pamoate salt is a metallic pamoate salt, optionally selected from sodium pamoate and potassium pamoate.

4. A method, according to any of the preceding claims, characterized in that the reaction mixture is a solution, such as an aqueous solution, optionally water or a buffered aqueous solution.

5. A method according to any of the preceding claims, characterized by further comprising: (i) providing a solution of the first atosiban salt; and (ii) contacting the solution of the first atosiban salt with the inorganic pamoate salt; and optionally further comprising: (iii) adding the inorganic pamoate salt to the solution of the first atosiban salt, optionally further comprising adding a solution of the inorganic pamoate salt to the solution of the atosiban salt.

6. Method, according to any of the preceding claims Petition 870250088789, dated 09 / 30 / 2025, p. 38 / 52 2 / 4, characterized in that the molar ratio between the atosiban salt and the inorganic pamoate used, brought into contact and / or reacted, is any molar ratio between about 10:1 and about 1:10, between about 5:1 and about 1:5 or between about 3:1 and about 1:

3.

7. A method according to any of the preceding claims, characterized by further comprising separating and / or removing the atosiban pamoate precipitate; and optionally (i) freeze-drying the atosiban pamoate precipitate to form freeze-dried atosiban pamoate; and / or (ii) spray-drying atosiban pamoate to provide spray-dried atosiban pamoate particles.

8. Method for providing atosiban pamoate particles, characterized by comprising: (i) providing an atosiban pamoate loading solution; and (ii) spray-drying the loading solution to form atosiban pamoate particles; optionally wherein the atosiban pamoate has a solubility in the loading solution of at least about 15 mg / ml, at least about 20 mg / ml or at least about 25 mg / ml.

9. Method according to claim 8, characterized in that atosiban pamoate is substantially stable and / or exhibits minimal or no degradation in the loading solution when stored for a period of at least 1 hour, at least 2 hours, at least 3 hours, at least 4 hours, at least 12 hours, at least 24 hours, at least 36 hours or at least 48 hours; optionally in which atosiban pamoate maintains at least about 98.9%, at least about 99.0%, at least about 99.1%, at least about 99.2%, at least about 99.3%, at least about 99.4% or at least about 99.5% of an original purity level when stored in the loading solution.

10. Method according to claim 8 or 9, characterized in that the loading solution: (a) having a boiling point less than or equal to about 150 °C, less than or equal to about 125 °C or less than or equal to about 100 °C; and / or (b) comprising one or more solvents, optionally wherein the one or more solvents are selected from alcohol, water and acetonitrile; and / or (c) comprising a solvent system selected from: (i) an alcohol (for example, a C1-C4 alcohol, such as methanol); (ii) an alcohol (for example, a C1-C4 alcohol, such as methanol) and water; and (iii) acetonitrile and water.

11. Method according to any one of claims 8 to 10, characterized in that the loading solution comprises a solvent system selected from: (i) approximately 5:1 alcohol (for example, a C1-C4 alcohol, such as methanol):water (v / v); and (ii) approximately 3:1 acetonitrile:water (v / v).

12. Loading solution for a spray drying process, characterized by comprising atosiban pamoate and a solvent system selected from: (i) approximately 5:1 alcohol (e.g., a C1-C4 alcohol, such as methanol):water (v / v); and (ii) approximately 3:1 acetonitrile:water (v / v).

13. Spray-dried atosiban pamoate particle, characterized by being obtained or obtainable by a method, as defined in any of claims 8 to 11, optionally, in Petition 870250088789, dated 09 / 30 / 2025, page 40 / 52 4 / 4, wherein the particles comprise a diameter between about 0.1 μm and about 50 μm (microns), between about 0.5 μm and about 25 μm, or between about 1 μm and about 10 μm.

14. Atosiban pamoate salt, characterized in that: (i) the molar ratio between atosiban and pamoate in the salt is approximately 2:1; and / or (ii) the salt is obtained or obtainable by a method as defined in any one of claims 1 to 7.

15. Pharmaceutical composition, characterized by comprising atosiban pamoate obtained or obtainable by a method as defined in any of claims 1 to 7, a spray-dried atosiban pamoate particle as defined in claim 13, or the atosiban pamoate salt as defined in claim 14. Petition 870250088789, dated 09 / 30 / 2025, pp. 41 / 52

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