Improved Synthesis of Acetylsalicylic Acid Lysine-Glycine Particles

Abstract

The present invention provides an improved method for preparing acetylsalicylic acid lysine glycine (LASAG) that allows for high yields without the need for the addition of seed crystals, resulting in a controlled small particle size (preferably less than 40 μm median particle size) and high stability of the LASAG. Advantageously, the method can be carried out at room temperature without adversely affecting the yield or particle properties. The present invention also provides LASAG obtained from said method, and its use as a pharmaceutical product.

Description

[Background technology]

[0001] Acetylsalicylic acid (or "ASA" for short) has been used therapeutically for over 100 years. It is most commonly known under the trade name Aspirin®. In particular, o-acetylsalicylic acid is widely used as an analgesic, antipyretic or antirheumatic drug, as well as a nonsteroidal anti-inflammatory drug, in arthritis, neuralgia or muscle pain. Unfortunately, acetylsalicylic acid has limited solubility in water, limiting its absorption rate and forming potential applications. Some acetylsalicylic acid salts have been found to show significantly improved resorption rates. In particular, salts of acetylsalicylic acid with basic amino acids, especially lysine, show greatly improved absorption rates.

[0002] A commonly used salt of acetylsalicylic acid in this context is acetylsalicylic acid lysinate, also known as acetylsalicylic acid lysine, or simply "LASA". The salt has been known for over 60 years and has been utilized in several pharmaceutical compositions and applications. The advantage of acetylsalicylic acid lysinate is its high tolerability in oral applications, as well as its increased absorption rate compared to acetylsalicylic acid alone.

[0003] A further important compound is acetylsalicylic lysine·glycine (sometimes called L-, D-, or D,L-acetylsalicylic lysine·glycine, or L-, D-, or D,L-acetylsalicylic lysine+glycine, or simply "LASAG", depending on the lysine stereoisomer used), in which LASA is supplemented with or associated with the further amino acid glycine, which provides, among other things, improved stability. Glycine can be added to LASA either "externally" (e.g., in the form of a solid mixture with LASA powder, as described in WO2018115434) or "internally" in the form of a cocrystal (i.e., when glycine is already added during the LASA crystallization step, such that glycine is incorporated within the LASA crystal lattice, as described in WO200205782 or WO2006128600).

[0004] The synthesis of both acetylsalicylic acid lysinate (LASA) and LASAG has been the subject of several optimization attempts. Unfortunately, the different synthesis methods have several minor or major drawbacks. The synthesis methods commonly used today include the use of an excess of lysine (compared to the moles of o-acetylsalicylic acid used) and acetylsalicylic acid lysinate seed crystals, for example, as described in WO200205782 or WO2006128600. One drawback of using seed crystals is the higher risk of contamination of the final product.

[0005] Some other methods for synthesizing acetylsalicylic acid lysinate (LASA), such as WO2011039432, do not appear to require seed crystals, but have lower yields compared to methods that utilize seed crystals (e.g., only about 70% yield compared to 90-95% yield in WO200205782).

[0006] WO 2018115434 describes a method for the preparation of acetylsalicylic acid lysinate (LASA), in particular LASA with the addition of glycine (LASAG), which does not require the addition of seed crystals but provides a high yield of up to about 90-95%, together with improved LASA stability (compared to LASA without added glycine), and a reduced product formation time. Advantageously, the particle size of the LASAAG thus obtained is smaller than that of the products of the prior art, such as those described in WO 200205782 (median particle size of <100 μm compared to mean particle size of >160 μm, respectively). By controlling the particle size of the LASAG, it is possible to control important parameters such as the dissolution rate (also called dissolution rate) and therefore the rate of absorption in the body and therefore the manifestation of the pharmacological effect. A minor drawback of the method described in WO2018115434 is that in order to ensure the stabilizing effect of glycine on the LASA and to reduce the risk of powder segregation of the LASA+glycine solid mixture, the glycine particles must be provided with a particle size that approximately matches that of the LASA (e.g., to prevent particle segregation during manufacture and storage). To this end, WO2018115434 proposed to recrystallize glycine in an acetone / water mixture before mixing it with the LASA.

[0007] With regard to particle size, theoretically, ASA particles or particles of amino acid salts thereof with smaller particle sizes as described above can be obtained by simple grinding, but it should also be understood that this approach is not at all recommended for heat-sensitive drugs such as ASA. The heat generated during grinding adversely affects their stability, leading to a shortened shelf life. Therefore, drug synthesis processes that inherently result in drug particles with the desired small particle size, such as those described in WO2018115434, are superior to processes that require further manipulation of the resulting synthesized drug particles.

[0008] Another drawback of the prior art processes described in the above documents is that many of their reaction steps, especially the crystallization / incubation steps, require to be carried out at temperatures below room temperature, more specifically below about 5° C., or even at low temperatures below 2° C. (e.g. 0-2° C., 0° C., or −15-0° C.), which is a clear disadvantage in terms of time and energy consumption.

[0009] Furthermore, LASAG particles obtained from prior art processes such as those described in WO2006128600 appear to exhibit a bimodal particle size distribution (PSD), i.e., two peaks or maxima visible on the PSD graph. This can result in particle segregation and / or poor flow properties of the powder bed during the manufacturing process of the pharmaceutical product in pharmaceutical manufacturing machines with powder flow of LASAG particles. As a result, particle segregation and poor powder flow behavior can adversely affect dosing accuracy.

[0010] Additionally, the inventors have also noticed that the LASAG particles of prior art processes such as WO2006128600, especially when formulated as a dry powder for reconstitution, tend to adhere to glass surfaces, e.g., the inner walls of glass vials in which ASA or its salts are typically packaged, shipped, and stored. This apparent glass-sticking tendency can limit visibility into the vial and thus affect vial handling. For example, users run the risk of not seeing potential foreign objects and / or discolorations inside the vial that require disposal, or inexperienced users may unknowingly not be able to dissolve and retrieve the full intended dose from the vial when the drug material is stuck to the top edge of the vial near the stopper, and the water may not reach it without actively tilting or shaking the vial.

[0011] Therefore, there is still a need for new and improved synthesis methods that i) allow the incorporation of glycine in a manner that reduces the risk of powder separation or demixing, ii) do not require seed crystals, and iii) preserve a high yield of acetylsalicylic acid lysinate (LASA), preferably 90% or more. Furthermore, there is a need for LASAG syntheses that allow for the easy preparation of LASAG particles with improved stability and a defined small particle size (preferably with a median particle size of less than 50 μm), thus ensuring rapid dissolution of LASAG powder, for example, upon reconstitution with water into injection and / or inhalation solutions. Furthermore, there is a need for LASAG syntheses that overcome at least some of the problems of the prior art mentioned above (e.g., processes that are unnecessarily time- and energy-consuming, such as processes that require cooling for at least some of their processing steps, and / or drug materials with bimodal particle size distribution (PSD) and / or well-defined glass adhesion).

[0012] It is therefore an object of the present invention to provide said synthesis method and stable LASAG powders having rapid dissolution characteristics, as well as reduced glass adhesion tendency, and preferably a unimodal particle size distribution (PSD) to facilitate safe, easy and accurate handling.

[0013] Further objects of the present invention will become apparent based on the following description of the invention, examples and claims. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] International Publication No. 2018115434 [Patent Document 2] International Publication No. 200205782 [Patent Document 3] International Publication No. 2006128600 [Patent Document 4] International Publication No. 2011039432 Summary of the Invention

[0015] In a first aspect, the present invention relates to a method for preparing acetylsalicylic acid lysine-glycine (LASAG), comprising the steps of: (a) providing a solution of acetylsalicylic acid (ASA) in ethanol; (b) adding glycine to the solution of step a to form a suspension; (c) providing an aqueous solution of lysine; (d) combining the solution of step c with the suspension of step b; (e) optionally stirring the suspension of step d; (f) adding acetone to the suspension of step d or e; (g) incubating the suspension, optionally under agitation, to allow for the formation of the acetylsalicylic acid lysine glycine (LASAG) product; (h) isolating the acetylsalicylic acid lysine·glycine (LASAG) product of step g.

[0016] In a second aspect, the present invention provides acetylsalicylic acid lysine glycine (LASAG) obtainable or obtainable by a method according to the first aspect of the invention.

[0017] In a third aspect, the present invention provides acetylsalicylic acid lysine glycine (LASAG) according to the second aspect of the invention for use as a medicament.

[0018] In a fourth aspect, the present invention provides an acetylsalicylic acid lysine glycine (LASAG) according to the second aspect of the invention for use in: - Treatment and / or prevention of viral infections in humans or animals; -Treatment and / or prevention of acute coronary syndromes (including unstable angina and myocardial infarction); -Treatment of fever; -Treatment of acute moderate to severe pain (including migraine). [Brief description of the drawings]

[0019] [Figure 1A] FIG. 1 shows the particle size distribution (PSD) of prior art LASAG particles present in Bayer's commercial product Aspirin® iv (presumably prepared by a prior art process such as that described in WO2006128600). [Figure 1B] 1 shows the particle size distribution (PSD) of LASAG particles prepared according to the present invention ("LASAG 2"). [Diagram 2] Illustrates the stability over time of LASAG according to the invention and of prior art LASAG present in Aspirin® iv in aqueous solution, in solutions kept either at room temperature (i.e., as used herein, a temperature in the range of 20±5° C. or 15-25° C., as defined, for example, by the European Pharmacopoeia or the 2003 WHO guidance "Guidelines for the Storage of Essential Medicines and Other Health Commodities") or refrigerated (i.e., as used herein, a temperature in the range of 5±3° C. or 2-8° C.), expressed as the increase in salicylic acid (SA) content, in weight percent, in the stored LASAG solutions, as determined by HPLC. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] We have found an improved method for the preparation of lysine-glycine acetylsalicylic acid (LASAG) that does not require the addition of seed crystals, shortens the product formation time, reduces energy consumption, and provides very high yields (≥90%). The method further allows the production of LASAG particles with a defined small particle size, a monomodal particle size distribution, as well as a lower tendency to adhere to glass surfaces. All these advantages can be achieved without compromising the stability of the LASAG particles.

[0021] In a first aspect, the present invention relates to a method for preparing acetylsalicylic acid lysine-glycine (LASAG), comprising the steps of: (a) preparing a solution of acetylsalicylic acid (ASA) in ethanol, said solution being optionally filtered in step a1; (b) adding glycine to the solution of step a to form a suspension; (c) providing an aqueous solution of lysine; (d) combining the solution of step c with the suspension of step b; (e) optionally stirring the suspension of step d; (f) adding acetone to the suspension of step d or e; (g) incubating the suspension, optionally under agitation, to allow for the formation of the acetylsalicylic acid lysine glycine (LASAG) product; (h) isolating the acetylsalicylic acid lysine·glycine (LASAG) product of step g.

[0022] Acetylsalicylic acid, within the context of the present invention, preferably refers to o-acetylsalicylic acid, i.e., unless otherwise stated, "acetylsalicylic acid" or "ASA" refers to its ortho form. The same applies to the respective acetylsalicylic acid lysine glycine (LASAG) derived from said acetylsalicylic acid.

[0023] The solutions of steps (a) and (c) should contain sufficiently pure compounds and be based on pharmaceutical grade solvents. The same applies to the acetone added in step (f). The compounds acetylsalicylic acid and lysine, as well as the glycine added in step (b) are preferably at least substantially pure, more preferably at least pharmaceutical grade purity, and most preferably essentially free of impurities.

[0024] In one embodiment of this method, acetylsalicylic acid lysine-glycine (LASAG) is obtained in the form of a co-crystal. As used herein, this means that glycine is embedded or incorporated within the crystal lattice of acetylsalicylic acid lysine (LASA), or that the two crystals are otherwise bonded or intergrown with one another (e.g., glycine bound to LASA via hydrogen bonds, or LASA precipitated around glycine) to form a LASAAG compound, such that glycine is inseparable from LASA. For simplicity, this may also be referred to herein as "internal crystal" or "internal" glycine (as opposed to "external" glycine, which would be present, for example, in a solid mixture of glycine and LASA, where glycine is added after synthesis or crystallization of the LASA particles, as described, for example, in WO2018115434).

[0025] In this method, it is important that the molar amount of acetylsalicylic acid exceeds the molar amount of lysine in the final mixture. Thus, in one embodiment of the method, acetylsalicylic acid is used in excess compared to lysine. For example, in a particular embodiment, acetylsalicylic acid is used in at least a 1.02-fold molar excess, preferably at least a 1.04-fold, more preferably at least a 1.05-fold excess, compared to lysine. In further particular embodiments, acetylsalicylic acid (ASA) and lysine are used in a molar ratio ranging from 1:0.99 to 0.70, or 1:0.98 to 0.80, or 1:0.97 to 0.90, or 1:0.96 to 0.92, for example, a molar ratio of 1:0.9, or a molar ratio of 1:0.95. In an exemplary embodiment, about 1.5 kg of ASA (about 0.833 mol of ASA) was mixed with about 1.3 kg of D,L-lysine monohydrate (about 0.791 mol of lysine). In this regard, the preparation method according to the present invention differs from prior art processes such as those described in WO200205782 or WO2006128600, which use an excess of lysine compared to ASA (e.g., an ASA-lysine molar ratio of 1:1.05 to 1:1.5).

[0026] In one embodiment of the method, no seed crystals are added during the preparation. In particular, no seed crystals comprising or consisting of acetylsalicylic acid (ASA), acetylsalicylic acid lysine (LASA) or acetylsalicylic acid lysine glycine (LASAG) are added during the preparation. This distinguishes the preparation method according to the invention from prior art processes such as those described in WO200205782 or WO2006128600, which require the use of seed crystals to obtain higher yields.

[0027] In certain embodiments of this method, acetylsalicylic acid is used in excess relative to lysine and no seed crystals are added during preparation. In more specific embodiments of this method, acetylsalicylic acid is used in excess relative to lysine and no seed crystals comprising or consisting of acetylsalicylic acid (ASA), acetylsalicylic acid lysine (LASA), or acetylsalicylic acid lysine-glycine (LASAG) are added during preparation.

[0028] The solutions of steps a and c may be pretreated before use. Pretreatment includes any treatment before using the solution in the method, and may include, for example, heating or cooling, filtering, and / or irradiating the solution before using in the method. For example, the ASA solution of step a is pretreated before adding glycine in the subsequent step b, or the lysine solution of step c is backfilled before combining it with the ASA-glycine suspension of step b in the subsequent step d. In one embodiment, at least one of the solutions of steps a and c is heated or cooled, filtered, and / or irradiated before using in the method. The same applies mutatis mutandis to the suspension of step b, except for the pretreatment by filtration, since the filtration step removes the added glycine powder from the suspension.

[0029] In one embodiment of the method, the ethanolic ASA solution of step a is freshly prepared before the subsequent step. When referring to ethanol as a solvent herein, dehydrated ethanol denatured with 2% cyclohexane is typically used. However, absolute ethanol (100 V / V%), or dehydrated ethanol denatured with substances other than cyclohexane, are considered equally suitable. Ethanol 96 V / V% can also be used. However, in this case, it is recommended to compensate for its higher inherent water content by using a lower amount of water in the other steps of the method according to the first aspect of the invention. In a further embodiment of the method, the ethanolic ASA solution of step a is prepared at an elevated product temperature, for example about 30±5° C. (i.e., using mild heat to help dissolve ASA), optionally in a reaction vessel equipped with a temperature-controlled jacket, with a jacket temperature of about 30° C. In a particular embodiment of the method, the ethanolic ASA solution of step a is freshly prepared at an elevated product temperature, such as about 30±5° C., before the subsequent step. In more specific embodiments of the method, particularly when an elevated product temperature, such as about 30±5° C., is used to aid in dissolution of the ASA, the ethanolic ASA solution of step a or a1 is cooled to room temperature (i.e., as used herein, a temperature in the range of 20±5° C.) prior to step b, optionally with stirring to aid cooling.

[0030] In one embodiment of the method, the ethanolic ASA solution of step a comprises or consists of at least about 8 wt% acetylsalicylic acid and ethanol. In a particular embodiment of the method, the ethanolic ASA solution of step a comprises or consists of about 8 to 20 wt%, or about 12 to 19 wt%, or about 14 to 18 wt% acetylsalicylic acid and ethanol, for example about 16.7 wt%, based on the final weight of the ASA solution. For example, in one exemplary embodiment, 1.5 kg of acetylsalicylic acid may be dissolved in 9.5 L of ethanol (≧96 V / V%) under stirring, optionally using an elevated product temperature, such as about 30±5° C., to aid in the dissolution of ASA. This distinguishes the preparation method according to the present invention from prior art processes such as those described in WO200205782 or WO2006128600, which suggest lower ASA concentrations in the range of 1 to 10 wt%, preferably 6-8 wt%.

[0031] As mentioned above, the solutions of steps a and c can be pretreated before their use.In an optional embodiment of the method, the ethanolic ASA solution of step a is filtered in step a1 before any of the subsequent steps, in particular before the addition of glycine, and optionally filtered for sterile filtration and / or depyrogenation, since the latter is not soluble in the ethanolic ASA solution and therefore interferes with the filtration step.

[0032] In one embodiment of the method, glycine is added as a dry powder to the ethanolic ASA solution of step a or a1. In this respect, the preparation method according to the present invention differs from the prior art methods, such as those described in WO200205782 or WO2006128600, which teach the use of a glycine solution or suspension. Optionally, the added glycine powder is recrystallized glycine, obtained by dissolving glycine in water, adding acetone to the glycine solution, and stirring the mixture until glycine precipitation is obtained, as described, for example, in WO2018115434.

[0033] In a further embodiment of the method, the glycine of step b is added to the ethanolic ASA solution of step a or a1 in a weight ratio of acetylsalicylic acid to glycine ranging from 1:0.28 to 0.09, or 1:0.24 to 0.14, for example, 1:0.21, or 1:0.19, or 1:0.17. For example, in one exemplary embodiment, 279 g of glycine powder is added under stirring to a solution of 1.5 kg of ASA dissolved in 9.5 L of ethanol (≧96 V / V%), the stirring speed being selected to allow a homogeneous, agglomerate-free dispersion of the glycine powder while avoiding unnecessarily high stirring speeds that may result in the evaporation of excess ethanol.

[0034] In yet a further embodiment of the method, glycine in step b is added to the ethanolic ASA solution of step a or a1 in an amount to result in a glycine content of about 8 to 12 wt%, or 9 to 11 wt%, or about 10 wt%, based on the final isolated LASAG product of step h.

[0035] In step c of the method, a lysine solution is provided.Preferably, lysine is used in the form of free base, such as its stereoisomer (L- or D-lysine), its racemate (D,L-lysine), or its solvate, including hydrate, such as lysine monohydrate.Although it is possible to use lysine in the form of a salt (e.g., lysine hydrochloride), it is preferred to use lysine in the form of its free base, for example as lysine monohydrate.However, when any ratio or concentration of lysine is mentioned herein, these are based on lysine only, regardless of whether, for example, monohydrate is used.

[0036] In one embodiment of the method, the aqueous solution of lysine provided in step c is prepared from lysine monohydrate, optionally L- or D,L-lysine monohydrate. In a particular embodiment, the aqueous solution of lysine provided in step c consists of lysine monohydrate, optionally L- or D,L-lysine monohydrate, and water.

[0037] The solution containing lysine is preferably more concentrated than the solution containing acetylsalicylic acid. In one embodiment, the aqueous solution of lysine provided in step c comprises or consists of at least about 41 wt% lysine and water, and lysine is optionally provided in the form of L- or D,L-lysine monohydrate. In a particular embodiment, the aqueous solution of lysine provided in step c comprises or consists of about 41 to 55 wt% lysine, or about 40 to 50 wt% lysine, or about 44 to 48 wt% lysine and water, for example, 45.7 wt% lysine based on the final weight of the lysine solution. For example, in an exemplary embodiment, the lysine solution may be prepared from about 1.3 kg of D,L-lysine monohydrate and 1.25 L of water. This distinguishes the preparation method according to the invention from prior art methods such as those described in WO200205782 or WO2006128600, which suggest the use of a lysine solution containing only 10-40 wt.%, preferably only 20-30 wt.% lysine. Due to the higher lysine concentrations used in the method according to the invention, pure water (i.e. without the addition of further solvents such as ethanol or acetone) is the preferred dissolution medium for the preparation of the lysine solution. Furthermore, the use of a higher lysine concentration advantageously allows to significantly reduce the amount of ethanol and / or acetone used in the preparation method.

[0038] As mentioned above, the solutions of steps a and c may be pretreated before their use. In any embodiment, the lysine solution of step c is filtered, optionally sterile filtered, and / or filtered for depyrogenation in step c1, before the subsequent steps.

[0039] The combining step d can be carried out in any suitable manner. In one preferred embodiment, the ASA-glycine suspension of step b and the lysine solution of step c are provided at room temperature (20±5° C.) for step d, or, if applicable, can be cooled (optionally under stirring) to room temperature before step d. In a further preferred embodiment, the ASA-glycine suspension of step b and the lysine solution of step c are further combined slowly at room temperature in step d, optionally with stirring of the formed mixture (step e). Ideally, the mixture starts to crystallize during the mixing process, as indicated, for example, by the suspension growing thicker. In other words, at least the method steps a-d, or steps a-e, do not require cooling to a temperature below room temperature, more specifically below 15° C., or below 10° C., and in particular do not require cooling to a temperature near or below the freezing point of 0° C., for example about −5 to 5° C. In this regard, the preparation method according to the present invention differs from prior art processes such as those described in WO2006128600, which require cooling to -5 to 10°C, preferably 0 to 5°C (e.g., 2°C in Example 1), and prolonged stirring of at least 1 hour before adding glycine to the cooled ASA and lysine solution.

[0040] Moreover, as mentioned above, the mixture formed in step d or e usually starts to crystallize already during the mixing process, i.e. forms at least an initial precipitate, noticeable by the suspension growing thicker. No seed crystals are required or added for this purpose (in particular no seed crystals comprising or consisting of acetylsalicylic acid (ASA), acetylsalicylic acid lysine (LASA) or acetylsalicylic acid lysine glycine (LASAG)), and usually the first precipitate forms within 10 minutes, e.g. within 5 minutes.

[0041] In one embodiment, the combining step d is carried out at ambient pressure.

[0042] In one preferred embodiment of the method, the combining step d is carried out by adding the lysine solution of step c to the ASA-glycine suspension of step b, preferably while stirring the formed mixture.For example, in one exemplary embodiment, the lysine solution may be prepared from about 1.3 kg of D,L-lysine monohydrate and 1.25 L of water, and then added to the ethanol ASA-glycine suspension (e.g., 1.5 kg of dissolved ASA and 279 g of glycine powder in 10.5 L of ethanol (≧96 V / V%)).In this example, the lysine solution may be added at a rate of, for example, about 0.9 kg of lysine solution and kilograms of ASA-glycine suspension per minute.

[0043] It is generally preferred that the volume of the ethanolic ASA solution in step a exceeds the volume of the lysine solution in step c. Preferably, the volume of the ethanolic ASA solution in step a is at least about 2 times, preferably at least about 3 times, more preferably at least about 4 times the volume of the lysine solution in step c. In certain embodiments, the volume of the ASA-glycine suspension in step b exceeds the volume of the lysine solution in step c.

[0044] Preferably, the ASA-glycine suspension of step b and the lysine solution of step c are combined for less than 1 hour, more preferably less than 30 minutes, more preferably less than 15 minutes, even more preferably less than 10 minutes, and most preferably less than 5 minutes.

[0045] Typically, while combining the ASA-glycine suspension of step b with the lysine solution of step c in step d, the mixture is stirred to ensure its homogeneity before adding acetone in step f, as shown in step e. Alternative means of mixing other than stirring, such as air jets, can also be applied if available.

[0046] In one embodiment of the method, the suspension of step d or e (i.e., the mixture of the ASA-glycine suspension of step b and the lysine solution of step c) is stored and optionally stirred for less than 24 hours, preferably less than 12 hours, or less than 6 hours, or less than 3 hours, more preferably less than 1 hour, before adding acetone in step f. For example, in one exemplary embodiment, the suspension of step e is stirred at about 150 rpm for about 45 minutes before adding acetone thereto.

[0047] After the combination step d and optional stirring in step e, acetone is added to the suspension of step d or e in step f. In one embodiment, the amount of acetone added is less than the amount of the suspension of step e. In a more specific embodiment, the amount of acetone added is also less than the amount of the ethanolic ASA solution of step a, or in other words, the volume of the ethanolic ASA solution of step a exceeds the volume of acetone added in step f. This distinguishes the preparation method according to the invention from prior art processes such as those described in WO200205782 or WO2018115434, which explicitly require a volume of acetone in excess of the volume of the ASA solution.

[0048] The addition of acetone should result in a supersaturated mixture, leading to improved and faster crystallization with higher yields. Therefore, the amount of acetone used should be sufficient to ensure supersaturation of the mixture. In a preferred embodiment of the present invention, acetone is added after crystallization begins, i.e., after the first precipitate is formed. Typically, the first precipitate should be formed in step d or e within 10 minutes without the use of seed crystals, as described above. In some embodiments of the present invention, the first precipitate is formed within 5 minutes.

[0049] In one embodiment of the method, at least method steps b-g are carried out at or below room temperature (20±5°C). However, working at room temperature is clearly advantageous insofar as it is convenient and efficient, since it saves energy for cooling while still providing a high yield of 95% or more, and is therefore preferred herein. Thus, in one preferred embodiment, at least incubation step g is carried out at room temperature (20±5°C). This distinguishes the preparation method according to the invention from prior art methods, such as those described in WO2011039432 or WO2006128600, which require lower temperatures in the range of -15 to +15°C or 0 to 5°C, respectively, for incubation step g after the addition of acetone. WO2006128600 clearly highlights the importance of carrying out the incubation and crystallization of the products of the prior art in a narrowly defined temperature range of only about 0 to 2°C, recommending that the temperature should not exceed 5°C, and preferably not exceed 3°C. Thus, the preparation method according to the invention clearly offers advantages over the prior art processes, being easier and more energy efficient. The addition of acetone in step f is preferably carried out at the same temperature as steps d and e or at the same temperature as incubation step g. Thus, in one preferred embodiment, step f is carried out at room temperature. This means that in one preferred embodiment, all method steps a-g are carried out at room temperature, in other words, all method steps a-g do not require cooling to a temperature below room temperature, more specifically below 15°C or below 10°C, in particular to a temperature near or below the freezing point of 0°C, for example about -5 to 5°C.

[0050] As mentioned above, not requiring cooling below room temperature is advantageous with respect to the time and energy consumption of the synthesis process. Nevertheless, the advantage of being able to carry out the method according to the invention, especially its steps a-g, at room temperature should not be misconstrued as meaning that it must be carried out at room temperature or can only be carried out at room temperature. In particular in the mixing and incubation steps d-g, lower temperatures as proposed in the prior art (e.g., about -15 to 5°C) can still be used without this choice adversely affecting the yield and / or particle properties, such as particle size, particle size distribution, or glass adhesion behavior, of the LASAG particles obtained. In other words, it is not outside the scope of the present invention to choose to operate at lower temperatures, such as 10°C or lower, or 5°C or lower, while carrying out the process according to the first aspect of the present invention, in the order described herein and with the components described herein.

[0051] After the addition of acetone, the suspension of step f (i.e., the mixture of the ASA-glycine suspension of step b, the lysine solution of step c, and the added acetone of step f) should be incubated to allow the formation or completion of the formation of the acetylsalicylic acid lysine glycine (LASAG) cocrystal. As mentioned above, the incubation step g is preferably performed at room temperature (20±5° C.) or below, optionally under stirring. The suspension can be incubated for as long as deemed necessary to obtain a high yield, typically at least about 30 minutes. However, one advantage of the method according to the invention is the short incubation time in step g. High yields of product are achieved with incubation times of 3 hours or less. Thus, in one embodiment of the present invention, the suspension is incubated, optionally under stirring, for about 3 hours or less, preferably about 2 hours or less, more preferably about 1 hour or less. In one preferred embodiment, the suspension is incubated for about 30 to 60 minutes.

[0052] Of course, longer stirring times, such as overnight stirring, can be used if deemed more appropriate from the standpoint of product stability and / or for the general timing of the individual process steps. For example, in one exemplary embodiment, the suspension is stirred at about 20° C. for 17±1 hours to allow for the formation and precipitation of acetylsalicylic acid lysine glycine (LASAG) particles. These particles have been found to be particularly stable. In a further embodiment of the method, the suspension of step g is stored and optionally stirred for no more than 24 hours, preferably no more than 20 hours, more preferably no more than 18 hours, before recovery or isolation of the LASAG particles in step h.

[0053] After incubation in step g, the precipitated product is isolated in step h. Any method that allows separation of the precipitated product from the liquid is suitable. In one embodiment of the method, product isolation step h is performed by filtration. In an alternative embodiment of the method, product isolation step h is performed by centrifugation. Optionally, product isolation step h is performed by filtration and centrifugation, i.e. both techniques are used for isolation.

[0054] In one embodiment, the method further comprises step i of washing the isolated product, for example to remove impurities. In a particular embodiment, washing step i comprises washing the isolated product with ethanol and / or acetone. In a further particular embodiment, washing step i comprises washing the isolated product with ethanol, preferably washing it twice, optionally three times, with ethanol. In a further particular embodiment, washing step i comprises washing the isolated product with ethanol, followed by washing the isolated product with acetone, optionally repeating these washing steps.

[0055] The isolation step h and optional washing step i are preferably carried out at the same or similar temperature as the incubation step g. That is, typically at room temperature (20±5° C.) or lower. In less common cases, when a different temperature is used, the mixture containing the LASAG product to be isolated, optionally to be washed, and / or the product itself may or may not be adapted to the temperature used after incubation. For example, if the incubation step g is carried out at 5° C. (although this is not necessary) and isolated at 20° C., the mixture and / or the product may or may not be warmed to 20° C. before the isolation step h is completed.

[0056] After isolating and washing the product, the product may be optionally dried.In the context of the present invention, the term drying refers to removing solvent residues, preferably removing excess water, ethanol and acetone.Solvent can be removed by any suitable method, and drying under reduced pressure until reaching 15 mbar or less, optionally at a temperature of about 30°C, is one of the preferred means of drying.

[0057] In one embodiment, the method is carried out under aseptic conditions. For example, as described above, the ethanolic acetylsalicylic acid solution in step (a) and / or the lysine solution in step (c) may be optionally pretreated by sterilization and / or depyrogenation filtration to sterilize the solution before use.

[0058] Alternatively, the method includes an additional step carried out under non-sterile conditions, typically by irradiation, optionally gamma irradiation, of the product obtained in step h or i. Radiation is the preferred means of sterilization of the obtained LASAG particles, since the raw material is heat sensitive and therefore not suitable for heat sterilization methods.

[0059] This method is particularly suitable for producing LASAG particles with a defined particle size.In one embodiment of this method, for example, the product particles obtained in step h or i have a median particle size (D50) of less than 40 μm, or less than 30 μm, or less than 20 μm.This particle size is inherently obtained by following the method described herein, and does not require further manipulation of the obtained synthetic drug particles, such as grinding to this small particle size, which may adversely affect heat-sensitive drugs.

[0060] Unless otherwise stated, particle size values ​​provided herein (measured or calculated / derived from measurements) refer to particle size and were determined using a laser diffraction instrument and its associated evaluation software (here, for example, a Mastersizer® instrument from Malvern Instruments Ltd), and all laser diffraction measurements were in accordance with the ISO-13320 standard. When referring to particle size measurements, all percentages provided herein (such as "at least 90% of the particles have a particle size of ...") should be understood as volume percentages.

[0061] In a further embodiment of the method, at least 90% of the particles obtained in step h or i have a particle size (D90) of less than 65 μm, or less than 55 μm, or less than 45 μm.

[0062] In certain embodiments, the particles of the product obtained in step h or i have a median particle size (D50) of less than 40 μm and at least 90% of the particles have a particle size (D90) of less than 65 μm, or a D50 value of less than 30 μm and a D90 value of less than 55 μm, or a D50 value of less than 20 μm and a D90 value of less than 45 μm.

[0063] In one embodiment, the product particles obtained in step h or i exhibit a D90 / D50 ratio of 3.7 or less, or 3.4 or less, or 3.1 or less (or in other words, a narrow particle size distribution). In a further embodiment of the method, the product particles obtained in step h or i exhibit a unimodal particle size distribution (PSD), i.e. only one peak or maximum is visible in a PSD graph as shown in Figure 1A or Figure 1B.

[0064] A unimodal particle size distribution is beneficial insofar as it helps to reduce particle segregation and / or poor flow properties of the powder bed during the manufacturing process of a pharmaceutical product in a pharmaceutical manufacturing machine with a powder flow of LASAG particles. As a result, the reduction of particle segregation and the improvement of the powder flow behavior also help to improve the dosing accuracy. This advantageous homogeneous powder flow behavior further applies to particles such as LASAG described herein that exhibit not only a unimodal particle size distribution, but also one that further occurs with a D90 / D50 ratio of 3.7 or less, or 3.4 or less, or 3.1 or less.

[0065] Particle size distribution (PSD) data for the various LASAG particles are also shown in Table 1 and Figures 1A and 1B. When available, three or more batches of material were tested and their PSD data were averaged.

[0066] In one embodiment, the method exhibits a yield of at least 90%, or at least 92%, or at least 94%, or at least 96%, such as 97%, said yield being based on the amount of lysine and glycine used in the method according to the first aspect of the invention. In certain embodiments, the method exhibits a yield in the range of 90% to 100%, or 94% to 99%, or 96% to 98%.

[0067] In any embodiment of the method, the aqueous solution of lysine provided in step c further comprises dissolved glycine.

[0068] One of the main advantages of the method according to the first aspect of the invention is that i) it allows the incorporation of glycine in a manner that reduces the risk of powder separation or demixing of LASA and glycine, ii) no seed crystals are required to achieve high purity of the product after short product formation times, even at industrial scale, and iii) the yield of acetylsalicylic acid lysine glycine (LASAG) is high, preferably 90% or more. Furthermore, as mentioned above, the method according to the first aspect of the invention also does not require cooling below room temperature to achieve these yields and results in LASAG particles that offer several beneficial properties (e.g., higher dissolution rates, narrow monomodal particle size distribution, reduced glass adhesion tendency, and inherently small median particle size of less than 40 μm with good stability performance, etc.). Other methods used at industrial scale require the use of seed crystals and / or cooling well below room temperature and / or they result in significantly lower yields than the method of the invention.

[0069] In a second aspect, the present invention provides lysine glycine acetylsalicylate (LASAG) obtainable by or obtained by a method according to the first aspect of the invention. For brevity, these LASAG particles may be referred to herein as "LASAG 2".

[0070] All embodiments, including all specific or preferred embodiments, described above in relation to the method of the first aspect of the invention also apply to the LASAG and particles thereof according to this second aspect of the invention.For example, in one embodiment, the LASAG according to the second aspect of the invention is in the form of a co-crystal, i.e., glycine is embedded or incorporated into the crystal lattice of acetylsalicylic acid lysine (LASA), or is otherwise bound or intergrown with LASA.It is referred to herein as internal crystalline glycine.

[0071] As mentioned above, the LASAG particles obtainable by or obtained by the method according to the first aspect of the invention have a median particle size (D50) of less than 40 μm, or less than 30 μm, or less than 20 μm (see, for example, Table 1). In other words, these LASAG particles are smaller than the prior art LASAG particles with internal crystalline glycine described in WO200205782, in which an average particle size of more than 160 μm, preferably more than 170 μm, was considered beneficial, in which 60%, preferably 70% of the particles were in the size range of 100 to 200 μm). They are also smaller than the prior art LASAG particles with internal crystalline glycine described in WO2006128600, in which an average particle size of less than 100 μm, preferably less than 70 μm, was disclosed, and which are likely used in currently available commercial Aspirin® iv products (see, for example, Table 1).

[0072] While differences in particle size are shown in Table 1 (e.g., LASAG 2 compared to LASAG present in Aspirin® iv and presumably prepared by the process described in WO2006128600), the inventors found clinically relevant differences in dissolution rate, as shown in Example 2 below.

[0073] In a further embodiment, at least 90% of the LASAG particles according to the second aspect of the present invention have a particle size (D90) of less than 65 μm, or less than 55 μm, or less than 45 μm (see, for example, Table 1). This means that these LASAG particles means are smaller than those described in, for example, WO2006128600, and smaller than the LASAG particles of the applicant's prior art, such as those described in WO2018115434, which have D90 values ​​of about 200 μm and about 100 μm, respectively, compared to only about 50 μm for the LASAG of the present invention. See, for example, Table 1.

[0074] In certain embodiments, the LASAG particles have a median particle size (D50) of less than 40 μm, and at least 90% of the particles have a particle size (D90) of less than 65 μm, or a D50 value of less than 30 μm and a D90 value of less than 55 μm, or a D50 value of less than 20 μm and a D90 value of less than 45 μm.

[0075] As mentioned above, by controlling the particle size of the LASAG, parameters such as the rate of dissolution (also referred to as dissolution rate) can be controlled. Due to the greater surface-to-volume ratio of the smaller particles, the LASAG according to the second aspect of the invention dissolves significantly faster than larger sized prior art LASAG particles, such as those described in WO2006128600 (potentially used in commercially available Aspirin IV). For example, using the same technique of injecting 5 mL of water through the top seal into an 8 mL glass vial for injection purposes, filling each vial with 1000 mg of LASAG, and then manually shaking or swirling the contents until completely dissolved (no residual solids visible to the human eye), it has been noticed that the LASAG particles according to the second aspect of the present invention ("LASAG 2") require less time and / or manual shaking / swirling motions to completely dissolve than prior art LASAG particles present, for example, in Aspirin® iv, i.e., only 3-5 shaking / swirling motions in about 15-30 seconds for "LASAG 2" versus 8-10 shaking / swirling motions in about 40-60 seconds for Aspirin® iv (see, e.g., Example 2). The insert into the Aspirin® iv product (state of July 2019) further suggests under item "6.6. Special precautions" that the reconstituted solution should preferably be filtered through a 5 μm filter before its application, indicating a potential problem of (rapid) dissolution. In particular, taking into account that LASAG is used above all for the treatment of myocardial infarction, i.e. an acute health crisis in which time is of the essence, a more rapid and more easily occurring dissolution of the LASAG used could represent a clinically relevant advantage.

[0076] Advantageously, the faster dissolution characteristics of the LASAG particles according to the second aspect of the invention ("LASAG 2") do not affect the stability of the compound in water. The "LASAG 2" particles exhibit comparable stability in aqueous solution to prior art LASAG particles present in Aspirin® iv products, as shown for LASAG degradation-related formation of salicylic acid in Figure 2. Respective methods for determining stability in aqueous solution are described in Example 5 below.

[0077] In one embodiment, the LASAG particles exhibit a D90 / D50 ratio of 3.7 or less, or 3.4 or less, or 3.1 or less. In other words, the LASAG particles according to the second aspect of the present invention exhibit a narrower particle size distribution (PSD) than the LASAG particles of the prior art. For example, the particles in the tested Aspirin IV product (presumably prepared according to WO2006128600) exhibit a D90 / D50 ratio of 5.5 or more, and the LASAG particles of the applicant's prior art (prepared according to WO2018115434) exhibit a D90 / D50 ratio of 3.8 or more. See, for example, Table 1.

[0078] In further embodiments, the LASAG particles exhibit a unimodal particle size distribution, which distinguishes them from prior art LASAG particles found, for example, in commercially available Aspirin® iv, which exhibit a double-peak, or in other words, bimodal, particle size distribution (see, e.g., Figures 1A and 1B).

[0079] Both a lower D90 / D50 ratio and / or a unimodal particle size distribution indicate more uniformly sized LASAG particles, which is beneficial insofar as it avoids or at least reduces the risk of particle separation during, for example, the filling and dosing process (e.g., in the feed hopper), transportation and storage. Without wishing to be bound by theory, the inventors believe that this more uniform particle size distribution of the LASAG according to the second aspect of the invention ("LASAG 2") is related to the formation of finer crystals overall, compared to the coarser prior art LASAG crystals found in the commercially available Aspirin® iv product. This difference is also seen, for example, in the X-ray powder diffraction (XRPD) data, where Aspirin® iv particles exhibited sharper glycine-related reflections than LASAG 2. No amorphous fraction was identified in the XRPD data obtained for LASAG 2 crystals, indicating a very well crystallized product.

[0080] In one embodiment, the LASAG particles have low adhesion to glass surfaces, e.g., 0.250 mg / cm 2 Less than 0.200 mg / cm, preferably 0.200 mg / cm 2 It exhibits the following glass adhesion. This can be tested, for example, by filling a tared 8 mL glass vial, e.g., one commonly used as a container of powders for reconstitution, with 1000 mg of LASAG particles to be tested, closing the vial, and manually rotating it around all its axes to properly distribute the LASAG particles and allow them to coat the inner glass surface. This can be repeated, for example, over a period of 5 days. After opening the vial and emptying any unattached powder by simple gravity spill, the vial with the attached particles inside is weighed again, thereby determining the weight of the attached particles gravimetrically. Low glass adhesion allows for easier handling of the vial (e.g., better visibility inside the vial) and ensures that the full intended dose dissolves when water is added to the vial (e.g., added to the vial by injection through a needle, rather than some material that adheres to the top edge of the vial near the stopper, where the water may not reach).

[0081] In one embodiment, the LASAG particles have a diameter of 1.50 m as measured by BET gas adsorption technique. 2 / g or more, or 1.75m 2 / g or more, or 2.00m 2 / g or more, or 2.25m 2 For example, in one exemplary embodiment, the LASAG particles exhibit a specific surface area of ​​2.4±0.1 m / g or greater. 2 / g. In contrast, the prior art LASAG present in Aspirin® iv has a specific surface area of ​​only 1.1±0.1 m in the same BET measurement. 2 Without wishing to be bound by theory, it appears that the smaller median particle size of the LASAG according to the present invention may be responsible not only for its faster dissolution but also for its higher specific surface area.

[0082] In one embodiment, the LASAG particles have a viscosity of 1.450 g / cm 3 or more than 1.460 g / m 3 or more than 1.470g / cm 3 It shows a density of more than 10 ...

[0083] In one embodiment, the LASAG particles exhibit a residual moisture content of 0.15 wt% or less, e.g., 0.10 wt% residual moisture, which is within the respective specifications of similar prior art LASAG products, such as Aspirin® IV (which requires a residual moisture content of 0.3 wt% or less), and which advantageously improves the storage stability of the dry "LASAG 2" particles, e.g., as shown in Table 2.

[0084] At 5±3°C (refrigerated), the samples do not exceed the upper degradation limit of ≤1.5 wt% salicylic acid for more than 60 months, i.e., 5 years. (See, for example, the extrapolated value of 70.9±3.5 months in Table 2.) After continuing the low-temperature storage stability study for an additional 12 months, this stability finding was reconfirmed and the extrapolated value increased from 70.9±3.5 months to 200±5 months.

[0085] In a third aspect, the present invention provides an acetylsalicylic acid lysine-glycine (LASAG) according to the second aspect of the invention for use as a medicament. To this end, the acetylsalicylic acid lysine-glycine (LASAG) according to the second aspect of the invention (in other words, LASAG particles obtainable or obtainable by a method according to the first aspect of the invention) may be prepared in any manner necessary to access a desired route of administration. For example, in some embodiments, the LASAG may be compressed into a tablet or filled into a capsule, typically with known pharma-ceutically acceptable excipients. In alternative embodiments, the LASAG particles may be used in powder form, e.g., in vials containing dried LASAG particles for reconstitution by addition of water for injection purposes.

[0086] In a fourth aspect, the present invention provides an acetylsalicylic acid lysine glycine (LASAG) according to the second aspect of the invention for use in: - Treatment and / or prevention of viral infections in humans or animals; -Treatment and / or prevention of acute coronary syndromes (including unstable angina and myocardial infarction); -Treatment of fever; -Treatment of acute moderate to severe pain (including migraine).

[0087] The following examples serve to illustrate the invention but should not be understood as limiting its scope. EXAMPLES

[0088] Example 1 - Preparation of a LASAG according to the invention ("LASAG 2"; laboratory scale) In a temperature-controlled jacketed reaction vessel, a quantity of 1.5 kg of acetylsalicylic acid (ASA) is dissolved in 9.5 L of ethanol (here anhydrous ethanol, denatured with 2% cyclohexane) at the temperature of the elevated product, i.e. with gentle warmth (here a jacket temperature of about 30° C.).

[0089] The freshly prepared, filtered, and optionally sterile filtered ASA solution is then cooled to a product temperature of 20±5° C. with stirring, after which 279 g of powdered glycine is added to the ethanolic ASA solution under stirring and uniformly suspended (here, e.g., 100 rpm), thereby forming a uniform ASA-glycine suspension. The transfer vessel is rinsed with 1.0 L of ethanol to ensure complete transfer of the intended amount of powdered glycine into the ASA solution.

[0090] Before adding lysine to this suspension, the stirring speed is increased slightly (here, for example, 100 rpm to 150 rpm) and the temperature of the product is reduced by about 5° C. to about 15±5° C. Then, a freshly prepared, filtered, and optionally sterile filtered solution of 0.95 mol equivalents of lysine (based on acetylsalicylic acid) in 1.25 L of demineralized water is added to the suspension in the reaction vessel over a few minutes (about 2-3 min), rinsing the transfer vessel with another 0.25 L of water to ensure that the intended amount of lysine is completely transferred to the ASA-glycine suspension. In this experiment, the lysine equivalent was provided in the form of 1282 g of D,L-lysine monohydrate (about 1.3 kg) having a hydrate content of about 9.8 wt%, i.e., about 1156 g of lysine with about 126 g of water of crystallization dissolved in 1.25 L of water.

[0091] After the addition of D,L-lysine monohydrate is complete, the suspension is stirred at 150 rpm for approximately 45 min, after which 7.5 L of acetone is added to it. The suspension is stirred for 17 ± 1 h at a jacket temperature of 20 °C to allow the formation and precipitation of acetylsalicylic acid lysine glycine (LASAG) particles.

[0092] The resulting suspension is filtered off and the filter cake is washed twice with ethanol and twice with acetone. The solid is dried under reduced pressure (starting at about ≦500 mbar) at a temperature of 30° C. until a final vacuum of ≦15 mbar is reached.

[0093] Example 2 - Dissolution behavior of LASAG according to the invention (manual) The dissolution behavior of LASAG according to the second aspect of the invention ("LASAG 2") was tested in comparison with prior art LASAG particles, such as present in Aspirin® iv. For this purpose, 8 mL glass vials were filled with 1000 mg of LASAG 2 particles and sealed with a stopper, to be comparable to commercially available Aspirin® iv vials. The amount of water for injection purposes, 5 mL, was injected through the sealing stopper over a period of about 25-30 seconds, then the needle was removed and the vial was manually shaken or swirled until completely dissolved (no residual solids visible to the human eye). The same test was performed with commercially available Aspirin® iv vials. Each test was repeated at least three times for each type of LASAG. It is believed that this test and the resulting dissolution behavior are similar to what would likely be observed, for example, when a paramedic in an ambulance or medical staff in a hospital dissolves dry LASAG particles in a pre-filled vial by adding water for injection purposes and shaking manually. A more standardized dissolution test is provided in Example 3.

[0094] It was found that the "LASAG 2" particles dissolved more quickly and easily than the prior art LASAG particles present in Aspirin® iv, with the "LASAG 2" sample requiring only about 15-30 seconds for needle removal and 3-5 shaking / swirling motions to completely dissolve, versus about 40-60 seconds and 8-10 shaking / swirling motions for the prior art LASAG particles present in the Aspirin® iv sample.

[0095] Example 3 - Dissolution behavior of LASAG according to the invention (shaker) The dissolution behavior of the LASAG according to the second aspect of the invention ("LASAG 2") was tested in a horizontal shaker (IKA®-Werke GmbH & Co. KG) in comparison with LASAG particles of the prior art, such as those present in Aspirin® iv. For this purpose, 25 mL glass test tubes were filled with 1000 mg of LASAG 2 particles and then placed on a horizontal shaker. An injection volume of 5 mL of water was added and the vial was shaken at 1055 rpm for 5 second intervals until complete dissolution (no residual solids visible to the human eye). The same test was performed with commercially available Aspirin® iv vials. Each test was repeated at least three times for each type of LASAG.

[0096] Again, it was found that the "LASAG 2" particles dissolved more quickly and easily than the prior art LASAG particles present in Aspirin® iv, with the "LASAG 2" samples requiring an average of only 18.3±2.9 seconds to completely dissolve, compared to 23±2.9 seconds for the prior art LASAG particles present in Aspirin® iv samples. While this difference of approximately 5 seconds may seem negligible, it should be understood that in emergency situations, a non-standardized manual dissolution procedure is much more likely than the use of a horizontal shaker, as outlined in Example 2.

[0097] Example 4 - Glass adhesion behavior of LASAG according to the invention The glass adhesion behavior of a LASAG according to the second aspect of the invention ("LASAG 2") was tested in comparison to prior art LASAG particles, such as those present in Aspirin iv. To this end, a 29 cm 3 LASAG was used to compare glass adhesion to a commercially available Aspirin iv vial. 2An 8 mL glass vial with an inner glass surface of 1000 mg (estimated assuming the vial is cylindrical) was filled with 1000 mg of LASAG 2 particles and sealed with a stopper to prevent moisture absorption and / or contaminants from falling into the vial during testing. For at least 5 consecutive days, the vial was moved manually or rotated around its entire axis once a day to ensure proper distribution of the LASAG particles and coating of the inner glass surface. After 7 days, the vial was simply inverted and all non-adherent powder was allowed to spill or fall under gravity, followed by emptiness by tapping the vial firmly five times on a solid surface. No significant adhesion to the stopper was observed. The remaining weight, i.e., the weight of LASAG powder still attached to the glass wall inside the vial after emptying, was determined gravimetrically. The same test was performed with commercially available Aspirin® iv vials. Each test was repeated at least three times for each type of LASAG.

[0098] The LASAG 2 particles adhered less to the inside of the glass vial than Aspirin® iv, with only 5.12±0.35 mg of LASAG 2 remaining in the vial compared to 9.00±1.58 mg (approximately 0.177 mg / cm) of Aspirin® iv. 2 to approximately 0.312 mg / cm 2 Furthermore, the amount of LASAG 2 particles adhering to the glass was less variable than with Aspirin® iv.

[0099] A reduction in glass adhesion would be beneficial insofar as drug that adheres to the glass at the top, e.g., near the stopper, may be lost upon injection of the reconstitution medium (e.g., water for injection purposes) and dosing may become inaccurate if the vial containing the reconstituted LASAG solution is not shaken or is not shaken frequently enough to recover and dissolve the adhering LASAG particles. Moreover, a reduction in glass adhesion would also be beneficial during packaging procedures, especially at industrial scale where it would allow the LASAG 2 particles to stick less in the filling station.

[0100] Example 5 - Stability of LASAG according to the invention in solution Due to its instability in water, LASAG is generally used as a dry powder, specifically as a dry powder for reconstitution. In other words, its aqueous solution is not necessarily meant to be stored for long periods, but is freshly prepared before each use. Nevertheless, stability in aqueous solution is an important feature for users, for example, to know how long the prepared solution can still be used. A content of LASAG degraded salicylic acid (SA) of 1.5 wt% or less in solution is typically considered acceptable. Therefore, the stability of LASAG according to the second aspect of the invention in aqueous solution ("LASAG 2") was tested in comparison with prior art LASAG particles, such as those present in Aspirin IV. For this purpose, an amount of LASAG of 1.0 g was dissolved in 5.0 mL of water for injection in a crimped vial, and the respective contents of LASAG and LASAG degraded salicylic acid (SA) of the solution stored at room temperature (20±5°C) and at low temperature (5±3°C) were measured over time by HPLC (column) in 500 μL aliquots sampled. The vials remained closed between sample times.

[0101] The following time points were measured: JPEG2025501974000001.jpg17151

[0102] None of the solutions tested (i.e., those with "LASAG 2" and those with Aspirin® iv) showed any change in color or clarity over the time range tested or at the storage conditions tested.

[0103] For HPLC analysis, an Agilent Zorbax SB-C18 column was used (4.6 x 250 mm, 5 μm) at 22 °C with an eluent flow rate of 1 mL / min over 40 min isocratic elution. The eluent was an 80 mM ammonium acetate / acetonitrile solution (60:40) prepared by dissolving 4 g ammonium acetate in 600 mL HPLC grade water, adjusting the pH to 2.0 using trifluoroacetic acid, then adding 400 mL acetonitrile and homogenizing the mixture. The injected sample volume was 10 μL. Samples were analyzed using a UV detector at 237 nm.

[0104] The results are shown in FIG. 2, which shows the increase in salicylic acid (SA) content (weight percent) in aqueous LASAG solutions over time. As can be seen, when stored at room temperature, the "LASAG 2" solution exhibits the same stability as Aspirin® iv, with both solutions exceeding 1.5 wt% SA content in about 1 hour. Similar results were seen for solutions stored refrigerated at 5±3° C., with both solutions exceeding 1.5 wt% SA content in about 8 hours (08:14 hours for "LASAG 2" vs. 07:59 hours for Aspirin® iv). The latter results also indicate that - although not preferred or recommended - the reconstituted solutions can be used for up to 8 hours when continuously stored in a refrigerator at 5±3° C. immediately after reconstitution.

[0105] [Table 1]

[0106] [Table 2]

[0107] Below is a list of numbered items that are embodiments encompassed by the present invention.

[0108] 1. A method for preparing lysine acetylsalicylate glycine (LASAG), comprising: a) preparing a solution of acetylsalicylic acid (ASA) in ethanol, said solution being optionally filtered in step a1; b) adding glycine to the solution of step a to form a suspension; c) providing an aqueous solution of lysine; d) combining the solution of step c with the suspension of step b; e) optionally stirring the suspension of step d; f) adding acetone to the suspension of step d or e; g) incubating the suspension, optionally under stirring, to allow for the formation of the acetylsalicylic acid lysine glycine (LASAG) product; h) isolating the acetylsalicylic acid lysine-glycine (LASAG) product of step g. A method comprising:

[0109] 2. The method according to item 1, wherein acetylsalicylic acid lysine·glycine (LASAG) is obtained in the form of a cocrystal.

[0110] 3. The method of any one of the preceding items, wherein acetylsalicylic acid is used in excess compared to lysine.

[0111] 4. The method according to any one of the preceding items, wherein no seed crystals are added during the preparation, in particular no seed crystals comprising or consisting of acetylsalicylic acid (ASA), acetylsalicylic lysine (LASA) or acetylsalicylic lysine-glycine (LASAG).

[0112] 5. The method according to any one of the preceding items, wherein acetylsalicylic acid is used in excess compared to lysine and no seed crystals are added during the preparation, in particular no seed crystals comprising or consisting of acetylsalicylic acid (ASA), acetylsalicylic acid lysine (LASA) or acetylsalicylic acid lysine-glycine (LASAG).

[0113] 6. The method of any one of the preceding items, wherein the ethanolic ASA solution of step a is freshly prepared before the subsequent step.

[0114] 7. The method according to any one of the preceding items, wherein the ethanolic ASA solution of step a is prepared at the temperature of the hot product, for example about 30±5°C, optionally in a reaction vessel equipped with a temperature-controlled jacket, with a jacket temperature of about 30°C.

[0115] 8. The method of any one of the preceding items, wherein the ethanolic ASA solution of step a is filtered, and optionally sterile filtered, in step a1, prior to the subsequent step.

[0116] 9. The method of any one of the preceding items, wherein the ethanolic ASA solution of step a or a1 is cooled to room temperature (20±5° C.) prior to step b, optionally under stirring to aid cooling.

[0117] 10. The method of any one of the preceding items, wherein glycine is added as a dry powder to the ethanolic ASA solution of step a or a1, optionally in a weight ratio of ASA to glycine in the range of 1:0.28-0.09, or 1:0.24-0.14.

[0118] 11. The method of any one of the preceding items, wherein the combining step d is carried out by adding the lysine solution of step c to the ASA-glycine suspension of step b.

[0119] 12. The method according to any one of the preceding items, wherein acetylsalicylic acid and lysine are used in a molar ratio ranging from 1:0.99 to 0.70, or 1:0.98 to 0.80, or 1:0.97 to 0.90, or 1:0.96 to 0.92, for example, a molar ratio of 1:0.9, or a molar ratio of 1:0.95.

[0120] 13. The method of any one of the preceding items, wherein the ethanolic solution of acetylsalicylic acid provided in step a comprises or consists of about 8 to 20 wt.%, or about 12 to 19 wt.%, or about 14 to 18 wt.% acetylsalicylic acid, and ethanol, for example about 15.7 wt.%.

[0121] 14. The method according to any one of the preceding items, wherein the aqueous solution of lysine provided in step c comprises or consists of about 41 to 55 wt % lysine and water.

[0122] 15. The method according to any one of the preceding items, wherein the aqueous solution of lysine provided in step c is prepared from lysine monohydrate, optionally L- or D,L-lysine monohydrate.

[0123] 16. The method of any one of the preceding items, wherein the volume of the ethanolic ASA solution in step a exceeds the volume of acetone added in step f.

[0124] 17. The method according to any one of the preceding items, wherein at least method steps b to g are carried out at or below room temperature (20±5° C.).

[0125] 18. The method according to any one of the preceding items, wherein at least incubation step g is carried out at room temperature (20±5° C.).

[0126] 19. The method of any one of the preceding items, wherein the product isolation step h is carried out by filtration.

[0127] 20. The method according to any one of the preceding claims, wherein the product isolation step h is carried out by centrifugation.

[0128] 21. The method according to any one of the preceding items, wherein the product isolation step h is carried out by filtration and centrifugation.

[0129] 22. The method of any one of the preceding items, further comprising step i) washing the isolated product.

[0130] 23. The method according to item 22, wherein the washing step i comprises washing the isolated product with ethanol and / or acetone.

[0131] 24. The process according to items 22 to 23, wherein the washing step i comprises washing the isolated product with ethanol, preferably washing twice with ethanol.

[0132] 25. The method according to items 22 to 24, wherein the washing step i comprises washing the isolated product with ethanol followed by washing the isolated product with acetone, optionally repeating these washing steps.

[0133] 26. The method of any one of the preceding items, wherein the isolated and washed product is dried under reduced pressure, optionally at a temperature of about 30°C.

[0134] 27. The method of any one of the preceding items, wherein the method is carried out under sterile conditions.

[0135] 28. The method according to any one of items 1 to 27, which is carried out under non-sterile conditions and comprises an additional step of sterilizing the product obtained in step h or i by irradiation, optionally by gamma irradiation.

[0136] 29. The method according to any one of the preceding items, wherein the particles of the product obtained in step h or i have a median particle size (D50) of less than 40 μm, or less than 30 μm, or less than 20 μm.

[0137] 30. The method according to any one of the preceding items, wherein at least 90% of the particles obtained in step h or i have a particle size (D90) of less than 65 μm, or less than 55 μm, or less than 45 μm.

[0138] 31. The particles of the product obtained in step h or i have a median particle size (D50) of less than 40 μm and at least 90% of the particles have a particle size (D90) of less than 65 μm; or The particles of the product obtained in step h or i have a median particle size (D50) of less than 30 μm and at least 90% of the particles have a particle size (D90) of less than 55 μm; or 8. The method of any one of the preceding items, wherein the particles of the product obtained in step h or i have a median particle size (D50) of less than 20 μm and at least 90% of the particles have a particle size (D90) of less than 45 μm.

[0139] 32. The method according to any one of the preceding items, wherein the particles of the product obtained in step h or i exhibit a D90 / D50 ratio of 3.7 or less, or 3.4 or less, or 3.1 or less.

[0140] 33. The method according to any one of the preceding items, wherein the particles of the product obtained in step h or i exhibit a monomodal particle size distribution.

[0141] 34. The method of any one of the preceding items, exhibiting a yield of at least 90%, or at least 92%, or at least 94%, or at least 96%.

[0142] 35. The method of any one of the preceding items, wherein the method exhibits a yield in the range of 90% to 100%, or 94% to 99%, or 96% to 98%.

[0143] 36. The method of any one of the preceding items, wherein the aqueous solution of lysine provided in step c further comprises dissolved glycine.

[0144] 37. Lysine acetylsalicylic acid glycine (LASAG) obtainable or obtainable by a method according to any one of the preceding claims.

[0145] 38. The acetylsalicylic acid lysine-glycine according to item 37, wherein the acetylsalicylic acid lysine-glycine (LASAG) is in the form of a cocrystal.

[0146] 39. The acetylsalicylic acid lysine-glycine according to items 37 to 38, wherein the particles have a median particle size (D50) of less than 40 μm, or less than 30 μm, or less than 20 μm.

[0147] 40. The acetylsalicylic acid lysine-glycine according to items 37 to 39, wherein at least 90% of the particles have a particle size (D90) of less than 65 μm, or less than 55 μm, or less than 45 μm.

[0148] 41. The median particle size (D50) of the particles is less than 40 μm and at least 90% of the particles have a particle size (D90) of less than 65 μm; the particles have a median particle size (D50) of less than 30 μm and at least 90% of the particles have a particle size (D90) of less than 55 μm; or 41. The acetylsalicylic acid lysine-glycine according to items 37 to 40, wherein the particles have a median particle size (D50) of less than 20 μm and at least 90% of the particles have a particle size (D90) of less than 45 μm.

[0149] 42. The acetylsalicylic acid lysine-glycine according to items 37 to 41, wherein the particles exhibit a D90 / D50 ratio of 3.7 or less, or 3.4 or less, or 3.1 or less.

[0150] 43. The acetylsalicylic acid lysine-glycine according to items 37 to 42, wherein the particles exhibit a monomodal particle size distribution.

[0151] 44. The acetylsalicylic acid lysine-glycine according to any one of items 37 to 43, wherein the particles exhibit low adhesion to glass surfaces.

[0152] 45. When a particle is measured by the BET gas adsorption technique, it has a diameter of 1.50 m 2 / g or more, or 1.75m 2 / g or more, or 2.00m 2 / g or more, or 2.25m 2 45. The acetylsalicylic acid lysine-glycine according to any one of items 37 to 44, having a specific surface area of ​​1 / g or more.

[0153] 46. ​​A particle has a mass of 1.450 g / cm 3 or more than 1.460g / cm 3 or more than 1.470g / cm 3 46. ​​The acetylsalicylic acid lysine-glycine according to items 37 to 45, exhibiting a density of at least 1.

[0154] 47. The acetylsalicylic acid lysine-glycine according to items 37 to 46 for use as a medicine.

[0155] 48.-Treatment and / or prevention of viral infections in humans or animals; -Treatment and / or prevention of acute coronary syndromes (including unstable angina and myocardial infarction); -Treatment of fever; -Treatment of acute moderate to severe pain (including migraine headaches) 47. The acetylsalicylic acid lysine-glycine according to items 37 to 46, for use in

Claims

1. 1. A method for preparing lysine glycine acetylsalicylate (LASAG), comprising the steps of: a) providing a solution of acetylsalicylic acid (ASA) in ethanol; b) adding glycine to the solution of step a to form a suspension; c) providing an aqueous solution of lysine; d) combining the solution of step c with the suspension of step b; e) adding acetone to the suspension of step d; f) incubating the suspension to allow for the formation of the acetylsalicylic acid lysine glycine (LASAG) product; g) isolating the acetylsalicylic acid lysine glycine (LASAG) product of step f. A method comprising:

2. 2. The method of claim 1, wherein the acetylsalicylic acid lysine glycine (LASAG) is obtained in the form of a co-crystal.

3. excessive use of acetylsalicylic acid relative to lysine, and / or 10. The method of claim 1, wherein no seed crystals are added during the preparation.

4. 10. The method of claim 1, wherein the glycine is added to the ethanolic ASA solution of step a as a dry powder.

5. 2. The method of claim 1, wherein the ethanol solution of acetylsalicylic acid provided in step a comprises 8 to 20 wt %, or 12 to 19 wt %, or 14 to 18 wt % acetylsalicylic acid and ethanol, or consists of 8 to 20 wt %, or 12 to 19 wt %, or 14 to 18 wt % acetylsalicylic acid and ethanol, and / or the aqueous solution of lysine provided in step c comprises 41 to 55 wt % lysine and water, or consists of 41 to 55 wt % lysine and water.

6. 2. The method of claim 1, wherein at least method steps b to f are carried out at or below room temperature (20±5° C.).

7. 10. The method of claim 1, wherein said product isolation step g is carried out by filtration and / or centrifugation.

8. 10. The method of claim 1 further comprising step i) washing the isolated product.

9. 10. The method of claim 1, exhibiting a yield of at least 90%, or at least 92%, or at least 94%, or at least 96%.

10. 10. Lysine acetylsalicylate glycine (LASAG) obtainable or obtainable by the method according to any one of claims 1 to 9.

11. 11. The acetylsalicylic acid lysine glycine of claim 10, wherein the acetylsalicylic acid lysine glycine (LASAG) is in the form of a co-crystal.

12. the particles have a median particle size (D50) of less than 40 μm, or less than 30 μm, or less than 20 μm; and / or 11. The acetylsalicylic acid lysine glycine of claim 10, wherein at least 90% of the particles have a particle size (D90) of less than 65 μm, or less than 55 μm, or less than 45 μm.

13. The acetylsalicylic acid lysine glycine of claim 10, wherein the particles exhibit a monomodal particle size distribution and / or low adhesion to glass surfaces.

14. The acetylsalicylic acid lysine glycine of claim 10 for use as a medicine.

15. 11. The acetylsalicylic acid lysine glycine of claim 10 for use in the treatment and / or prevention of viral infections in humans or animals.

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