BR112020018096B1 - PROCESS FOR THE PREPARATION OF THE POLYMORPH FORM B OF TREPROSTINIL DIETHANOLAMINE SALT AND PROCESS FOR THE TRANSFORMATION OF THE POLYMORPH FORM A OR THE MIXTURE OF THE POLYMORPH FORMS A AND B OF THE TREPROSTINIL DIETHANOLAMINE SALT - Google Patents

Abstract

The present invention relates to a robust and reproducible process for the preparation of polymorph form B of treprostinyl diethanolamine salt, comprising the following steps: a. treprostinil is dissolved in methanol, b. to the solution of step a) is added diethanolamine or its solution in methanol, c. the reaction mixture from step b) is stirred until dissolved, d. when salt formation is completed in step c), first portion of an aprotic solvent is added to the solution, e.g. the solution from step d) is filtered to remove insoluble impurities, f. the filtrate from step e) is seeded with treprostinyl diethanolamine salt polymorph form B, g. to the suspension of crystals obtained in step f) a second portion of the aprotic solvent is added, h. the suspension from step g) is stirred until crystallization is complete, i. the crystals are separated, washed and dried.

Description

[0001] Treprostinil formula (II) are a synthetic prostacyclin derivative with vasodilatory effects and platelet aggregation inhibitors. It is the only prostacyclin derivative that can be applied subcutaneously, intravenously, or in inhaled and oral forms.

[0002] Its therapeutic fields involve the treatment of Pulmonary Arterial Hypertension (PAH), Drugs, 2012, 72(18) 2351-2363) and chronic thromboembolic pulmonary hypertension.

[0003] http://www.ema.europa.eu/docs/enGB/documentlibrary/O rphan designation/2009/10/WC500005505.pdf, download: 15 February 2017.)

[0004] Treprostinil sodium salt of formula (III) is on the market for injection use under the name Remodulin, for inhalation purposes under the name Tyvaso®.

[0005] Treprostinyl diethanolamine salt of formula (I) is the active ingredient of Orenitram, formulated as tablets.

[0006] The two polymorphous forms (forms A and B) of the crystalline treprostinyl diethanolamine salt were first described in patent specification WO2005/007081. The polymorphous forms were characterized by their melting point, powder X-ray diffraction pattern, DSC (Differential Scanning Calorimetry) and TGA (Thermogravimetric Analysis) curves, and by their hygroscopic character.

[0007] It has been established that: • the metastable form A is hygroscopic, it melts at 103°C, the DSC curve exhibits an endothermic peak at 103°C, and as disclosed by TGA, the crystals do not contain any solvated solvent, • the more stable form B is much less hygroscopic, it melts at 107°C, DSC curve shows endothermic peak at 107°C, TGA curve reports minimal weight loss at 100°C, • forms A and B show different diffractograms of pulverized: the characteristic peak of the most stable crystalline form B is 17.2o Theta, • form A in suspension made with various organic solvents (1,4-dioxane, isopropanol, tetrahydrofuran, toluene) transforms into form B with shaking at different temperatures.

[0008] The publication Organic Process & Development, 2009, 13, 242-249. (Crystallization Process Development for Stable Polymorph of Treprostinil; Batra, H.; Penmasta, R.; Phares, K.; Staszewski, J.; Tuladhar, S. M.; D. A. Walsh, United Therapeutics) describes in detail the physical characteristics of two polymorphs and the experiments carried out for their preparation. The metastable form A, which was first isolated, at rest transforms into the thermodynamically more stable form B.

[0009] Various solvent - antisolvent mixtures of various ratios were investigated. From mixtures of isopropanol: methyl t-butyl ether (TBME) mostly form A was obtained, but by stirring the crystal suspension for several hours, form A transformed into form B, this transformation, however, does not occur when put into scale.

[0010] Crystallization from mixtures of ethanol : acetone = 7:1 (yield 85-90%) and from ethanol : ethyl acetate = 7:1 (yield > 90%) leads to form B uniformly if the solution was seeded with form B, and cooling was very slow, controlled with several temperature steps.

[0011] The patent specification WO 2009/078965 discloses the preparation of high purity treprostinyl Na salt through crystalline treprostinyl diethanolamine salt.

[0012] To the solution of treprostinil in ethyl acetate, anhydrous ethanol and diethanolamine were added. The clear solution was stirred at 60-75°C for 30-60 minutes, cooled to 55 +/- 5°C and seeded with 1% amount of polymorph form B of treprostinyl diethanolamine salt. The precipitated crystals were stirred for 1 hour while maintaining the temperature, then the crystal suspension was cooled to 20-22°C. After 16-24 hours of stirring the crystals were collected by filtration, washed with ethyl acetate and dried, yield 88%.

[0013] If the melting point of the crystals of treprostinyl diethanolamine was > 104°C, then form B was obtained.

[0014] If the melting point of the resulting crystals of treprostinyl diethanolamine was < 104°C, then the mixture of forms A and B was present. In this case the mixture of crystals was repeatedly crystallized with ethanol:ethyl acetate/ethyl acetate mixture of solvents.

[0015] The process described above is thus neither robust nor reproducible, often mixing forms A + B is obtained.

[0016] WO 2014/089385 describes the preparation of treprostinyl, treprostinyl Na and treprostinyl diethanolamine salts.

[0017] For the preparation of treprostinyl diethanolamine salt, the ethyl acetate solution of treprostinyl was treated with the solution of diethanolamine in anhydrous ethanol, the suspension obtained was heated and maintained at reflux temperature for 15 minutes while all components dissolved . The solution was then slowly cooled over 18 hours to room temperature. The precipitated white crystalline material was filtered, washed with ethyl acetate and dried under vacuum at 50°C for 24 hours. 76% yield. Physical characteristics of salt are not given.

[0018] The patent specification IN 2014CH02963-A discloses the preparation of treprostinil, treprostinyl Na and salts of treprostinyl diethanolamine.

[0019] To the aqueous solution of diethanolamine was added the acetone solution of treprostinyl at 25-30°C. Optionally, the solution was seeded, then stirred for 15 minutes while maintaining the temperature. The suspension of crystals was cooled to 0-5°C, after 90 minutes of stirring the crystals were filtered, washed and dried. Yield: 79%, polymorph A. Crystals of polymorph A of treprostinyl diethanolamine salt were suspended in acetone, then at reflux temperature approximately 0.2% amount of ethanol was added to the suspension. After 6 hours of stirring at reflux temperature followed by cooling to 25-30°C the crystals were filtered, washed and dried. Yield 100%, polymorph B.

[0020] In the process described above, polymorph B of treprostinyl diethanolamine salt can only be prepared in two steps.

[0021] In the process described in patent specification US 2016/0152548, to form the salt treprostinyl and diethanolamine were dissolved in ethanol and ethyl acetate at 70°C, after 30 minutes of stirring the solution was cooled to 55°C , seeded with 1 wt% treprostinyl diethanolamine salt polymorph B seed crystals, the suspension was stirred at 55°C for one hour and cooled to room temperature. After 16 hours of agitation the crystals were filtered, washed and dried. Yield: 93%. Physical characteristics of the crystals (melting point, X-ray powder diagram, DSC, TGA) are not given.

[0022] Again in the process described above, mixture of ethanol - ethyl acetate was used for crystallization, similarly to the process of patent specification WO 2014/089385, which is known not to be robust and reproducible, and results in many cases , the mixture of forms A + B.

[0023] Our objective was to develop a process for the preparation of crystalline treprostinyl diethanolamine salt, which is robust, well reproducible, and provides the most stable polymorph B form of the salt in one step (i.e., one salt crystallization step of treprostinyl diethanolamine comprising the sequence of seeding, addition of antisolvent, cooling and filtration).

[0024] It is known from the literature that treprostinyl diethanolamine salt can crystallize in two polymorphous forms. The polymorph form with the lowest melting point (melting point 103°C) is the metastable form A, while the one with the highest melting point (melting point 107°C) is the thermodynamically more stable form B, so for prepare the active pharmaceutical ingredient, polymorph B is the desired form.

[0025] Preparation of the thermodynamically more stable form B, however, is not an easy task: even if we find an appropriate solvent - antisolvent ratio, carry out the dissolution at reflux temperature, apply seeding with form B, carry out cooling very slowly at in a controlled manner with several temperature steps, it is not guaranteed that the process will give the most stable form B in every case. As disclosed by the literature, it often happens that even if the predetermined parameters are strictly followed, forms A and B crystallize together, and the desired polymorph is finally obtained from a mixture of crystal forms A and B after an additional operational step (repeated crystallization, long stirring of the crystal suspension).

[0026] We organized the literature data and investigated which of the crystal forms is obtained by using various solvents or solvent mixtures (Table I) Table I. Literature methods for preparing crystalline Treprostinyl DEA *crystallization from solution **stirring the suspension of crystals containing form A or forms A+B ***scaled crystallization **** if A+B precipitates, crystallization is repeated

[0027] From Table I, which is simplified and does not contain the temperature profile of the crystallizations, the following conclusions can be drawn: • crystallization processes of patent specification WO 2005/007081 (1) lead to form A, or to the mixture of forms A + B. The desired form B can be obtained by subsequently stirring the crystal suspension for several days. • in accordance with publication (2) of Org. Proc. Res. & Dev.: . during the laboratory experiments the form A obtained primarily and also the mixture of forms A+B completely transformed into form B under the effect of long stirring with isopropanol or with mixtures of isopropanol : methyl t-butyl ether, however, during climbing there was no success to obtain form B. . crystallization from isopropanol:methyl tert-butyl ether mixtures provided form A.. by crystallization from mixtures of EtOH : acetone, the mixture in ratio of 1:7 generally leads to form B, but sometimes the mixture of forms A+B was obtained. In this case, the crystallization had to be repeated until crystals of form B were uniformly obtained. During the process the solution had to be seeded with crystalline form B, a complicated temperature profile had to be followed and the entire crystallization took 3 days. The process, however, is not robust, as only a small change in the solvent ratio can cause the mixture of A+B forms to crystallize. It is surprising, that instead of solvent mixture EtOH : acetone = 1:7 determined in laboratory experiments, mixture of EtOH = acetone = 1:10 was chosen during climbing. . by crystallization from mixtures of EtOH : ethyl acetate, the mixture of ratio 1:7 generally leads to form B, but in some cases the mixture of forms A + B was obtained. In these cases crystallization had to be repeated until crystals of form B were uniformly obtained. During the process, the solution had to be seeded with crystalline form B, and a complicated temperature profile had to be followed, the whole crystallization required a shorter time, approximately 1.5 days. The process, however, is also not robust with this mixture of solvents, since a small change in the solvent ratio can lead to crystallization of a mixture of A+B forms. It is surprising, that also in this method, for climbing another solvent ratio (EtOH : ethyl acetate = 1:8) was chosen, and not the one (EtOH : ethyl acetate = 1:7) verified more appropriate during the experiments of laboratory. • In patent specification WO 2009/078965 A1 (3) crystallization of treprostinyl diethanolamine salt was carried out with mixture of EtOH : ethyl acetate = 1 : 7. If form B did not crystallize, the crystallization has to be repeated, the process so it's not robust. • In the patent specification WO 2014/089385 A2 (4) crystallization of treprostinyl diethanolamine salt was performed with mixture of EtOH : ethyl acetate = 1:8. The crystal form has not been characterized, but it is known from literature data that this method is not robust for the preparation of form B. • According to patent specification IN 2014CH02963 (5) treprostinyl diethanolamine salt was crystallized from mixture of acetone : water which yields form A. Crystal form A, with stirring in mixture of acetone : EtOH transformed into form B. • In the patent specification process US 20165/0152548 A1 (6) salt of treprostinyl diethanolamine was crystallized with solvent mixture EtOH : ethyl acetate = 1:7. According to the description form B was obtained, but it is known from literature data that this method is not robust.

[0028] For industrial implementation, however, it is essential for a technology to be robust, simple, scalable, reproducible and easy to modality.

[0029] In light of the above, we wish to develop a process providing treprostinyl diethanolamine salt of formula I in the form of the thermodynamically more stable crystalline polymorph B reproducibly, in any case, in one step.

[0030] We performed numerous experiments to develop a method for preparing polymorph form B of treprostinyl diethanolamine salt. Our object was to carry out salt formation using such a solvent from which only polymorph B crystallizes.

[0031] In the experiments 1.0 g of treprostinil (II) was dissolved in the selected solvents. To the solution was added 0.3 g of diethanolamine (IV) and the reaction mixture was stirred at 35°C for 30 minutes. To the homogeneous solution the first portion of the antisolvent was added, the mixture was then cooled to room temperature and seeded with polymorph B of treprostinyl diethanolamine salt (I). After 1-2 hours of stirring the second portion of the antisolvent was added to the crystal suspension and stirring at room temperature was continued for an additional 16-24 hours.

[0032] Crystals of treprostinyl diethanolamine (I) were filtered, washed and dried under vacuum at 45°C. The crystal form was determined by DSC investigation and X-ray powder diffraction (XRPD).

[0033] To our surprise we found that from methanol with any of the antisolvents (methyl t-butyl ether, acetone, ethyl acetate, diisopropyl ether, acetonitrile) only form B was crystallized (for x-ray diffractograms of pulverized see figure 1), while using the solvents described in the literature both forms A and B were formed. Table II.: Preparation of crystalline salt of treprostinyl diethanolamine from methanol

[0034] It is to be noted that toluene is not a suitable antisolvent to crystallize treprostinyl diethanolamine salt, there was no success to obtain salt in crystalline form using toluene.

[0035] The most appropriate solvent to prepare the crystalline polymorph form B of treprostinyl diethanolamine salt was found to be methanol, since in the mode of crystallization from this solvent, form B always crystallizes uniformly.

[0036] As an antisolvent methyl t-butyl ether was chosen, due to technological reasons this solvent proved to be more suitable.

[0037] Treprostinyl diethanolamine salt formation was repeated four times in 1g sizes by using methanol - methyl t-butyl ether as solvent - antisolvent mixture, then the process was scaled up, starting from 70g of treprostinyl (II) ( example 7). In any case, polymorphic form B of the salt was uniformly obtained.

[0038] Our process is thus robust, and yields the desired shape B in one step. In addition, our process is technically more convenient because there is no need for programmed cooling, which is used in the prior art process.

[0039] To further justify the robustness of our process, treprostinyl diethanolamine salt preparation was repeated five times in 1g size. The amount of methyl t-butyl ether, the antisolvent for crystallization was varied over a wide range.

[0040] Treprostinyl (II) was dissolved in methanol (4 mL), diethanolamine (0.3 g) was added to the solution. After completion of salt formation, the first portion of methyl t-butyl ether was added (15 ml). The solution was filtered and the second portion of methyl t-butyl ether was added dropwise to complete crystallization.

[0041] In all cases form B of treprostinyl diethanolamine was crystallized as evidenced by XRPD and DSC. The characteristic peak of form B, i.e. 17.2° 2Theta is present in the XRPD pattern while characteristic peaks of form A are completely absent. Furthermore, DSC exhibits endothermic peak at a temperature that is equal to or greater than around 105°C in all cases. *ratio used for climbing

[0042] Crystallization was also carried out using mixture of solvent - ethanol antisolvent - ethyl acetate. In this case, in agreement with the literature data, the mixture of forms A+B was obtained (example 13). If this mixture of treprostinyl diethanolamine salt forms A and B was crystallized from methanol solvent mixture 1-methyl t-butyl ether, polymorph salt form B was uniformly obtained (Example 14).

[0043] Dissolving treprostinyl diethanolamine salt in aqueous methanol (approximately 30% water) and carrying out precipitation with acetone, we again obtained polymorph form B uniformly, but the yield was only 61% (Example 15).

[0044] Polymorph form B of treprostinyl diethanolamine salt was also obtained if the salt was dissolved in methanol, the solution was made opalescent with methyl t-butyl ether at 45°C and then crystallization was completed at room temperature (yield 87% ) (example 16).

[0045] However, crystallization from a solvent mixture of methanol - methyl t-butyl ether at -70°C provided highly hygroscopic crystals with low melting point. This form is named polymorphic form C (Example 17). Polymorph form C is a less stable form with a melting point of 86-88°C, at the bottom of the DSC curve, and in the DSC tube it transforms into the higher melting point form (101-103°C), more stable.

[0046] Based on the above, the object of our invention is process for the preparation of polymorph B form of treprostinyl diethanolamine salt, comprising the following steps: a. treprostinil is dissolved in methanol, b. to the solution of step a) diethanolamine or its solution in methanol is added, c. the reaction mixture from step b) is stirred until dissolved, d. when salt formation is completed in step c), first portion of an aprotic solvent is added to the solution, e.g. the solution from step d) is filtered to remove insoluble impurities, f. the filtrate from step e) is seeded with polymorph form B of treprostinyl diethanolamine salt, g. to the suspension of crystals obtained in step f) a second portion of the aprotic solvent is added, h. the suspension from step g) is stirred until crystallization is complete, i. the crystals are separated, washed and dried.

[0047] Still an object of our invention is a process for transforming polymorph form A or the mixture of polymorph forms A and B of treprostinyl diethanolamine salt into polymorph form B, uniformly, comprising the following steps: a. treprostinyl diethanolamine salt is dissolved in methanol, b. to the solution of step a) a first portion of aprotic solvent is added, c. the solution from step b) is filtered to remove insoluble impurities, d. the filtrate from step c) is seeded with polymorph form B of treprostinyl diethanolamine salt, e.g. to the crystal suspension from step d), a second portion of the aprotic solvent is added, f. the suspension from step e) is stirred until crystallization is complete, g. the crystals are separated, washed and dried.

[0048] In a preferred embodiment of the invention, dissolution of treprostinyl and diethanolamine or treprostinyl diethanolamine salt is carried out at 25-50°C, favorably at 30-40°C.

[0049] As for ethers, aprotic solvents such as methyl t-butyl ether, diisopropyl ether, ketone type solvent such as acetone, ester type solvent such as ethyl acetate or acetonitrile, preferably methyl t-butyl ether is applied .

[0050] The ratio of solvent (methanol): antisolvent is preferably 1 : 4-20, more preferably 1 : 5-15, and even more preferably 1 : 7-11.

[0051] In one embodiment of the process according to the invention crystalline form B of treprostinyl diethanolamine salt is prepared in a manner such that treprostinyl is dissolved in methanol at 35°C, solid diethanolamine base is added and the mixture is stirred at 35°C until dissolution. The first portion of the methyl t-butyl ether antisolvent is then added, the solution is filtered, the filtered solution is seeded with polymorph B form of treprostinyl diethanolamine salt, and the mixture is stirred at room temperature. To the suspension of crystals the second portion of the antisolvent is added and the mixture is stirred at room temperature until crystallization is completed. Recrystallization of polymorph form A or mixing of polymorph forms A and B of treprostinyl diethanolamine salt from methanol - methyl t-butyl ether provides treprostinyl diethanolamine salt form B.

[0052] Advantages of our process, compared to previous methods: • the method is simple, robust, scalable and well reproducible, • it provides the desired B shape in one step, • application is easy to scale because the complicated heating profiles - cooling are not required, • the following are not required: subsequent transformation of crystal form, . repeated crystallization and/or . long stirring of the crystal suspension, and/or . complicated heating-cooling profiles • it reproducibly provides the desired more stable polymorph B form. • the method is equally suitable for obtaining treprostinyl diethanolamine salt form B. via salt formation starting from treprostinyl and diethanolamine (IV), followed by crystallization of the resultant salt, . via transformation of form A or the mixing of forms A + B uniformly into form B, through crystallization.

[0053] Details of our invention are demonstrated by the following examples, without limiting the invention thereto.

[0054] Measurement conditions applied in the processes according to the invention:

[0055] X-ray diffractograms: Starting position [o2Theta]: 2.0084 Final position [o2Theta]: 39.9864 Measurement temperature [oC]: 25.00 Anode material: Cu K-alpha 1 [L] : 1.54060 K-alpha 2 [L]: 1.54443 DSC: Instrument: METTLER TOLEDO DSC1 STARe System, Stare basic V9.30 Method: Start temperature: 30°C End temperature: 150°C Heating rate: 5 °C/minute Amount: 2-6 mg, perforated aluminum crucible (40 μL) NMR: Instrument: Bruker Avance III 500 MHz Solvent: DMSO Brief description of drawings/figures:

[0056] Figure 1: X-ray powder diffraction patterns of different polymorphic forms of treprostinyl diethanolamine salt crystallized from methanol as solvent and different antisolvents (Examples 1 to 6)

[0057] 1.1: MeOH/methyl t-butyl ether

[0058] 1.2: MeOH/acetone

[0059] 1.3: MeOH/ethyl acetate

[0060] 1.4: MeOH/diisopropyl ether

[0061] 1.6: MeOH/acetonitrile

[0062] ,,A": polymorph A form of treprostinyl diethanolamine

[0063] ,,B": polymorph B form of treprostinyl diethanolamine

[0064] Figure 2: XRPD pattern of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture (Example 7)

[0065] Figure 3: DSC curve of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture (peak: 106.56oC, example 7)

[0066] Figure 4: XRPD pattern of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture (Example 8)

[0067] Figure 5: DSC curve of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture (peak: 106.23oC, example 8)

[0068] Figure 6: XRPD pattern of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture (Example 9).

[0069] Figure 7: DSC curve of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture (peak: 105.37oC, example 9).

[0070] Figure 8: XRPD pattern of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture (Example 10)

[0071] Figure 9: DSC curve of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture (peak: 104.91°C, example 10).

[0072] Figure 10: XRPD pattern of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture (Example 11).

[0073] Figure 11: DSC curve of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture (peak: 106.10°C, example 11).

[0074] Figure 12: XRPD pattern of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture (Example 12).

[0075] Figure 13: DSC curve of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture (peak: 107.42°C, example 12).

[0076] Figure 14: XRPD pattern of polymorphic forms A + B of treprostinyl diethanolamine salt crystallized from EtOH/ethyl acetate mixture (Example 13

[0077] Figure 15: DSC curve of polymorphic forms A + B of treprostinyl diethanolamine salt crystallized from an EtOH/ethyl acetate mixture (peaks: 103.84oC and 105.94oC, example 13.

[0078] Figure 16: DSC curve of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture (peak: 107.34oC, example 14).

[0079] Figure 17: DSC curve of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/water/acetone mixture (peak: 106.56oC, example 15).

[0080] Figure 18: DSC curve of polymorph form B of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture at 40-50°C (peak: 106.23oC, example 16).

[0081] Figure 19: XRPD pattern of polymorph form C of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture at -70°C (Example 17).

[0082] Figure 20: DSC curve of polymorphic form C of treprostinyl diethanolamine salt crystallized from MeOH/methyl t-butyl ether mixture at -70°C (peaks: 87.66°C and 102.58°C, example 17).

[0083] 13C and 1H NMR data of treprostinyl diethanolamine salt acquired at 500 MHz in DMSO. Examples Preparation of Treprostinyl Diethanolamine Salt (I) Diethanolamine salt of (1R,2R,3aS,9aS)-2-[2-hydroxy-1-[3(S)-hydroxyoctyl]-2,3,3a, 4,9,9a-hexahydro-1H-benz[f]inden-5-yloxy]acetic acid

Example 1 (JIM-562/1)

[0084] 1g of treprostinyl (II) is dissolved in 4 ml of methanol at room temperature. To the solution is added 0.3g of diethanolamine (IV) and the reaction mixture is stirred at 35+/-5°C for half an hour, then 15 mL of methyl t-butyl ether (TBME) is added. The solution is filtered, seeded with approximately 10 mg of crystals of polymorph B form, the suspension is stirred at room temperature for 2 hours and then 20 ml of methyl t-butyl ether are added dropwise. Stirring is continued at room temperature for 16-24 hours, then the crystals are filtered, washed and dried under vacuum at 45+/5°C.

[0085] Yield: 1.15g (91%), colorless crystals, corresponding to polymorph form B.

Example 2 (JIM-562/2)

[0086] 1g of treprostinil (II) is dissolved in 4 ml of methanol at room temperature. To the solution was added 0.3g of diethanolamine (IV) and the reaction mixture is stirred at 35+/-5°C for half an hour, then 15 mL of acetone is added, the solution is filtered, seeded with approximately 10 mg of crystals of polymorph form B, stirred at room temperature for 2 hours, then 30 mL of acetone is added dropwise. The suspension is stirred at room temperature for 16-24 hours, then the crystals are filtered, washed, and dried in vacuo at 45+/-5°C.

[0087] Yield: 0.92 g (73%), colorless crystals, corresponding to polymorph form B.

Example 3 (JIM-562/3)

[0088] 1g of treprostinil (II) is dissolved in 4 ml of methanol at room temperature. To the solution is added 0.3g of diethanolamine (IV) and the reaction mixture is stirred at 35+/-5°C for half an hour, then 15 mL of ethyl acetate is added, the solution is filtered, seeded with approximately 10 mg of crystals of polymorph B form, stirred at room temperature for 2 hours, then 20 mL of ethyl acetate is added dropwise. The suspension is stirred at room temperature for 16-24 hours, then the crystals are filtered, washed, and dried in vacuo at 45+/-5°C.

[0089] Yield: 1.16g (92%), colorless crystals, corresponding to the polymorph form B.

Example 4 (JIM-562/4)

[0090] 1g of treprostinil (II) is dissolved in 6 ml of methanol at room temperature. To the solution is added 0.3g of diethanolamine (IV), the reaction mixture is stirred at 35+/-5°C for half an hour, then 10 mL of diisopropyl ether (DIPE) is added, the solution is filtered, seeded with approximately 10 mg of crystals of polymorph B form, stirred at room temperature for 2 hours and then 20 mL of diisopropyl ether are added dropwise. The suspension is stirred at room temperature for 16-24 hours, then the crystals are filtered, washed and dried under vacuum at 45+/-5°C.

[0091] Yield: 1.20 g (95%), colorless crystals, corresponding to polymorph form B.

Example 5 (JIM-562-5)

[0092] 1g of treprostinil (II) is dissolved in 6 ml of methanol at room temperature. To the solution is added 0.3g of diethanolamine (IV), the reaction mixture is stirred at 35+/-5°C for half an hour, then 10 mL of toluene is added, the solution is filtered, seeded with approximately 10 mg of crystals of polymorph form B, stirred at room temperature for 2 hours and then 30 ml of toluene are added dropwise. No crystallization occurred.

Example 6 (JIM-562/6)

[0093] 1g of treprostinil (II) is dissolved in 4 mL of methanol at room temperature. To the solution is added 0.3g of diethanolamine (IV), the reaction mixture is stirred at 35+/-5°C for half an hour, then 15 mL of acetonitrile is added, the solution is filtered, seeded with approximately 10 mg of crystals of polymorph form B, stirred at room temperature for 2 hours and then 20 ml of acetonitrile are added dropwise. The suspension is stirred at room temperature for 16-24 hours, then the crystals are filtered, washed, and dried in vacuo at 45+/-5°C.

[0094] Yield: 1.15 g (91%), colorless crystals, corresponding to polymorph form B.

[0095] X-ray powder diffractograms of the treprostinyl diethanolamine salts prepared as described in Examples 1-6 are shown in Figure 1.

Example 7

[0096] 70g of treprostinil (II) are dissolved in 280 ml of methanol at 25+/-5°C. To the solution is added 20.73g of diethanolamine (IV) and the reaction mixture is stirred at 35+/-5°C for half an hour, then 1050 mL of methyl t-butyl ether (TBME) is added. The solution is filtered in an apparatus equipped with a stirrer, seeded with approximately 700 mg of crystals of polymorph form B and stirred at room temperature for 2 hours, then 1400 mL of methyl t-butyl ether are added in drops. Stirring is continued at room temperature for 16-24 hours, then the crystals are filtered, washed and dried under vacuum at 45+/-5°C.

[0097] Yield: 87.2g (98%), colorless crystals, corresponding to polymorph form B. DSC curve is shown in Figure 3, X-ray powder diffractogram in Figure 2.

[0098] 13C and 1H NMR data of treprostinyl diethanolamine salt are shown in Figure 21.

Example 8

[0099] 1g of treprostinil (II) is dissolved in 4 ml of methanol at 25+/-5°C. To the solution is added 0.3g of diethanolamine (IV) and the reaction mixture is stirred at 35+/-5°C for half an hour, then 15 mL of methyl t-butyl ether (TBME) is added. The solution is filtered in an apparatus adapted with a stirrer, seeded with approximately 10 mg of crystals of polymorph form B and stirred at room temperature for 2 hours, then 20 mL of methyl t-butyl ether are added in drops. Stirring is continued at room temperature for 16-24 hours, then the crystals are filtered, washed and dried under vacuum at 45+/-5°C.

[00100] Yield: 1.15 g (91%), colorless crystals, corresponding to polymorph form B.

[00101] DSC curve is shown in Figure 5, X-ray powder diffractogram in Figure 4.

Example 9

[00102] 1g of treprostinil (II) is dissolved in 4 ml of methanol at 25+/-5°C. To the solution is added 0.3g of diethanolamine (IV) and the reaction mixture is stirred at 35+/-5°C for half an hour, then 15 mL of methyl t-butyl ether (TBME) is added. The solution is filtered in an apparatus adapted with a stirrer, seeded with approximately 10 mg of crystals of polymorph form B and stirred at room temperature for two hours, then 25 mL of methyl t-butyl ether are added in drops. Stirring is continued at room temperature for 16-24 hours, then the crystals are filtered, washed and dried under vacuum at 45+/-5°C.

[00103] Yield: 1.15g (91%), colorless crystals, corresponding to polymorph form B.

[00104] DSC curve is shown in Figure 7, X-ray powder diffractogram in Figure 6.

Example 10

[00105] 1g of treprostinil (II) is dissolved in 4 ml of methanol at 25+/-5°C. To the solution is added 0.3g of diethanolamine (IV) and the reaction mixture is stirred at 35+/-5°C for half an hour, then 15 mL of methyl t-butyl ether (TBME) is added. The solution is filtered in an apparatus adapted with a stirrer, seeded with approximately 10 mg of crystals of polymorph form B and stirred at room temperature for 2 hours, then 29 mL of methyl t-butyl ether are added dropwise. Stirring is continued at room temperature for 16-24 hours, then the crystals are filtered, washed and dried under vacuum at 45+/-5°C.

[00106] Yield: 1.16g (92%), colorless crystals, corresponding to polymorph form B. DSC curve is shown in Figure 9, powder X-ray diffractogram in Figure 8.

Example 11

[00107] 1g of treprostinil (II) is dissolved in 4 ml of methanol at 25+/-5°C. To the solution is added 0.3g of diethanolamine (IV) and the reaction mixture is stirred at 35+/-5°C for half an hour, then 15 mL of methyl t-butyl ether (TBME) is added. The solution is filtered in an apparatus adapted with a stirrer, seeded with approximately 10 mg of crystals of polymorph form B and stirred at room temperature for 2 hours, then 9 mL of methyl t-butyl ether are added dropwise. Stirring is continued at room temperature for 16-24 hours, then the crystals are filtered, washed and dried under vacuum at 45+/-5°C.

[00108] Yield: 1.02g (81%), colorless crystals, corresponding to polymorph form B. DSC curve is shown in Figure 11, powder X-ray diffractogram in Figure 10.

Example 12

[00109] 1g of treprostinil (II) is dissolved in 4 ml of methanol at 25+/-5°C. To the solution is added 0.3g of diethanolamine (IV) and the reaction mixture is stirred at 35+/-5°C for half an hour, then 15 mL of methyl t-butyl ether (TBME) is added. The solution is filtered in an apparatus adapted with a stirrer, seeded with approximately 10 mg of crystals of polymorph form B and stirred at room temperature for 2 hours, then 5 mL of methyl t-butyl ether are added dropwise. Stirring is continued at room temperature for 16-24 hours, then the crystals are filtered, washed and dried under vacuum at 45+/-5°C.

[00110] Yield: 0.95g (75%), colorless crystals, corresponding to polymorph form B.

[00111] DSC curve is shown in Figure 13, X-ray powder diffractogram in Figure 12.

Example 13

[00112] 1g of treprostinil (II) is dissolved in 5 mL of ethanol at room temperature. To the solution was added 0.3g of diethanolamine (IV) and the reaction mixture is stirred at 35+/-5°C for half an hour, then 15 mL of ethyl acetate is added, the solution is filtered, seeded with approximately 10 mg crystals of polymorph form B, stirred at room temperature for 2 hours, then 20 mL of ethyl acetate (EtOH : EtOAc = 1:7) is added dropwise. The suspension is stirred at room temperature for 16-24 hours, then the crystals are filtered, washed and treated in vacuo at 45+/-5°C.

[00113] Yield: 1.1 g (87%), colorless crystals, mixture of polyform forms A and B. DSC curve is shown in Figure 15, X-ray powder diffractogram in Figure 14.

Example 14

[00114] 1g of treprostinyl diethanolamine salt (I, mixture of polymorph forms A and B) is dissolved in 4 ml of methanol at 35+/-5°C. To the homogeneous solution is added 15 mL of methyl t-butyl ether at room temperature and the mixture is seeded with approximately 10 mg of crystals of polymorph form B, stirred at room temperature for 2 hours, then 20 mL of methyl t-butyl ether were added in drops. Stirring is continued at room temperature for 16-24 hours, then the crystals are filtered, washed and dried under vacuum at 45+/-5°C.

[00115] Yield: 1.23g (97%), colorless crystals, corresponding to form B. DSC curve is shown in Figure 16.

Example 15

[00116] 0.5g of treprostinyl diethanolamine salt is dissolved in a mixture of 2 mL of methanol and 0.6 mL of water at room temperature. To the homogeneous solution 20 mL of acetone is dropped at room temperature, the opalescent solution is seeded with approximately 5 mg of crystals of polymorph form B, stirred at room temperature for two hours, then 10 mL of acetone is added dropwise. After 20 hours of stirring, the crystals are filtered, washed and dried under vacuum at 45+/-5°C.

[00117] Yield: 0.39g (61%), colorless crystals, corresponding to polymorph form B. DSC curve is shown in Figure 17.

Example 16

[00118] 0.5g of treprostinyl diethanolamine salt is dissolved in 2 ml of methanol at 45+/-5°C. To the homogeneous solution 20 mL of methyl t-butyl ether is added at 45+/-5°C and the mixture is seeded with approximately 5 mg of crystals of polymorph form B. The opalescent solution is cooled to room temperature. After 20 hours of stirring, the crystals are filtered, washed and dried under vacuum at 45+/5°C.

[00119] Yield: 0.55g (87g), colorless crystals, corresponding to polymorph form B. DSC curve is shown in Figure 18.

Example 17

[00120] 0.5g of treprostinyl diethanolamine salt is dissolved in 5 ml of methanol at -70°C. To the homogeneous solution is added 30 ml of methyl t-butyl ether at -70°C and the mixture is seeded with approximately 5 mg of crystals of polymorph form B. After 2 hours of stirring the opalescent solution is allowed to warm to room temperature. The not well filterable crystals are filtered, washed and dried under vacuum at 45+/-5°C.

[00121] Yield: 0.31g (49%), corresponding to the polymorphous form C.

[00122] DSC curve is shown in Figure 20, X-ray powder diffractogram in Figure 19.

Claims (10)

1. Process for the preparation of the polymorphic form B of the salt of treprostinil diethanolamine, characterized in that it comprises the following steps: a. treprostinil is dissolved in methanol, b. to the solution of step a) is added diethanolamine or its solution in methanol, c. the reaction mixture from step b) is stirred until dissolved. d. after termination of salt formation in step c) a first portion of aprotic solvent is added to the solution, e.g. the solution from step d) is filtered, f. the filtrate from step e) is seeded with treprostinyl diethanolamine salt polymorph form B, g. to the suspension of crystals obtained in step f), a second portion of the aprotic solvent is added, h. the suspension from step g) is stirred until crystallization is complete, i. the crystals are separated, washed and dried, in which the aprotic solvent is selected from ethers, ketones, esters and acetonitrile. 2. Process according to claim 1, characterized in that the dissolution of treprostinil and diethanolamine is carried out at 25-50°C. 3. Process according to claim 2, characterized in that the dissolution of treprostinil and diethanolamine is carried out at 30-40°C. 4. Process according to any one of claims 1 to 3, characterized in that methyl t-butyl ether, diisopropyl ether, acetone, ethyl acetate, or acetonitrile are applied as an aprotic solvent. 5. Process according to claim 4, characterized in that methyl t-butyl ether is used as an aprotic solvent. 6. Process for transforming the polymorphic form A or the mixture of polymorphic forms A and B of the treprostinyl diethanolamine salt into the polymorphic form B of the treprostinyl diethanolamine salt, characterized in that it comprises the following steps: a. treprostinyl diethanolamine salt is dissolved in methanol, b. to the solution of step a) is added a first portion of aprotic solvent, c. the solution from step b) is filtered, d. the filtrate from step c) is seeded with polymorph B form of treprostinyl diethanolamine salt, e.g. to the suspension of crystals obtained in step d), a second portion of the aprotic solvent is added, f. the suspension from step e) is stirred until crystallization is complete, g. the crystals are separated, washed and dried, in which the aprotic solvent is selected from ethers, polar ketones, esters and acetonitrile. 7. Process according to claim 6, characterized in that methyl t-butyl ether, diisopropyl ether, acetone, ethyl acetate or acetonitrile are applied as an aprotic solvent. 8. Process according to claim 7, characterized in that methyl t-butyl ether is used as an aprotic solvent. 9. Process according to any one of claims 6 to 8, characterized in that the dissolution of the treprostinyl diethanolamine salt is carried out at 25-50°C. 10. Process according to claim 9, characterized in that the dissolution of the treprostinyl diethanolamine salt is carried out at 30-40°C.