Patent Application
20230286898
This application claims the benefit of European Patent Application EP20382677.1 filed on July 27th, 2020
The present invention relates to a process for the purification of vilanterol trifenatate.
Vilanterol trifenatate is the generic name of compound (R)-4-(2-((6-(2-((2,6-dichlorobenzyl)oxy)ethoxy)hexyl)amino)-1-hydroxyethyl)-2-(hydroxymethyl)phenol 2,2,2-triphenylacetate, having the following chemical structure:
Vilanterol trifenatate is a selective long-acting beta2-adrenergic agonist. It is administered by inhalation as a dry powder formulation in combination with umeclidinium bromide and/or fluticasone furoate for the treatment of chronic obstructive pulmonary disease (COPD) and asthma.
Vilanterol trifenatate was first disclosed in document WO 2003/024439, which discloses a process wherein vilanterol trifenatate is crystallized in ethanol. Nevertheless, the product is obtained with an undesirable high impurity level.
Document WO 2014/041565 discloses crystallization of vilanterol trifenatate in acetone, which results in a decreased impurity level, at the expense of a significantly low yield. Additionally, acetone is highly flammable, highly reactive and harmful to human health and, thus, it is not a convenient solvent for industrial applicability.
Document WO 2017/001907 discloses a process for the preparation of vilanterol trifenatate, wherein vilanterol tartrate is converted in a multi-step process via the base (by addition of the corresponding acid) to the trifenatate salt. Allegedly, the process allows obtaining a product with a relatively high purity, particularly with a low amount of impurity A of the following formula:
However, the process is carried out in a mixture of DCM, MTBE, and EtOH, and requires a laborious workup.
Therefore, there is still the need of finding new methods that allow preparing vilanterol trifenatate in good yields and purity and, at the same time, which are of easy industrial applicability.
Inventors have found a new process for the purification of vilanterol trifenatate that overcomes the drawbacks of the processes disclosed in the prior art. Surprisingly, they have found that by crystallizing vilanterol trifenatate from some specific ketone solvents, a solid product is obtained in both good yields and high purity.
Thus, an aspect of the present disclosure refers to a method for the purification of vilanterol trifenatate of formula (I)
comprising crystallizing vilanterol trifenatate from a ketone solvent selected from the group consisting of methyl ethyl ketone (MEK), methyl isobutyl ketone (MIK), ethyl isopropyl ketone, methyl isopropyl ketone, 3-methyl-2-pentanone, and a mixture thereof.
All the terms used in the present description, unless otherwise indicated, are to be understood in their common meaning as known in the art.
The term “V” preceded by a number means how many times in terms of volume the amount of a substance exceeds the given amount of another substance in terms of weight. For example, given 7.5 g of vilanterol trifenatate, adding 8 V of MEK means to add 60 mL of MEK.
The term “seeding” refers to the addition of a crystalline material to facilitate crystallization. In the context of the present disclosure, seeding is carried out with crystals of vilanterol trifenatate.
The term “Ostwald ripening” refers to the growth of larger crystals from those of smaller size, which have a higher solubility than the larger ones by temperature cycling. In the process, many small crystals formed initially slowly disappear, except for a few that grow larger, at the expense of the small crystals. The smaller crystals act as fuel for the growth of bigger crystals. Ostwald ripening is the key process in the digestion of precipitates. The digested precipitate is generally purer, more homogeneous and easier to wash and filter.
The term “room temperature” refers to about 20° C. -25° C.
The term “about” comprises the range of experimental error which may occur in a measurement. In particular, when referred to a value, it means the given value plus or minus 5% and, when referred to a range, it means the outer values plus or minus 5%.
Processes of the prior art attempt to obtain vilanterol trifenatate with the highest purity as possible. Particularly, there is interest in providing a process that allows minimizing the presence of impurity A mentioned above in the final product. The inventors realized that the mentioned impurity proved to be difficult to remove, and even the subsequent recrystallization from the solvents disclosed in the prior art for this purpose did not allow obtaining the final product with the desired purity level and physical properties.
After extensive experimentation, the inventors have surprisingly found that crystallization of vilanterol trifenatate from methyl ethyl ketone (MEK), methyl isobutyl ketone (MIK), ethyl isopropyl ketone, methyl isopropyl ketone, 3-methyl-2-pentanone, or a mixture thereof, allows achieving the mentioned aims.
Thus, an aspect of the present disclosure refers to a method for the purification of vilanterol trifenatate comprising crystallizing vilanterol trifenatate from at least one of the mentioned ketone solvents. Particularly, the ketone solvent is selected from MEK, MIK, or a mixture thereof.
In a particular embodiment, the method of purification is carried out in MEK as the ketone solvent.
In another particular embodiment, the method of purification is carried out in MIK as the ketone solvent.
In an embodiment, optionally in combination with one or more features of the particular embodiments defined above, the method for the purification of vilanterol trifenatate comprises:
The term “appropriate amount” of the ketone solvent relates to the amount of the ketone solvent needed so that vilanterol trifenatate crystallizes when cooling of step b) is carried out. Particularly, the amount of the ketone solvent is such that vilanterol trifenatate is solved at its maximum concentration in the particular solvent, i.e. the solution is a saturated solution of vilanterol trifenatate, at the mentioned temperature.
Particularly, the method for the purification of vilanterol trifenatate in MEK comprises:
Particularly, the method for the purification of vilanterol trifenatate in MIK comprises:
A way to improve the crystallization process of the present invention, in particular of promoting crystallization in a controlled way, is by seeding with some crystals of the product. Accordingly, in another embodiment, optionally in combination with one or more features of the particular embodiments defined above or below, the method comprises seeding with vilanterol trifenatate crystals to initiate the crystallization. Particularly, after obtaining the solution of vilanterol trifenatate, the solution is cooled down to a temperature higher than room temperature, such as from 45° C. to 60° C., then seeded with vilanterol trifenatate crystals, and cooled down to a temperature from room temperature to 0° C., particularly to room temperature, to crystallize vilanterol trifenatate.
Isolation of vilanterol trifenatate crystals obtained according to the method of the present disclosure can be carried out according to methods known in the art, including, without being limited to, filtration, particularly filtration under vacuum. Then, the crystalline solid can be washed with the crystallization solvent at a temperature from room temperature to 0° C., particularly at room temperature, and dried at a temperature from 50° C. to 60° C. for a suitable time period until constant weight. A suitable time period can be, for example, from 10 to 20 hours, such as about 16 hours. The drying can be carried out according to methods known in the art including, but not limited to, drying under reduced pressure.
In a more particular embodiment, optionally in combination with one or more features of the particular embodiments defined above or below, the process comprises a previous step comprising adding triphenylacetic acid to a solution of vilanterol free base in the ketone solvent to form the solution of vilanterol trifenatate in the ketone solvent. Vilanterol free base can be obtained by any method known in the art, particularly a method wherein impurity A is formed.
In a more particular embodiment, optionally in combination with one or more features of the particular embodiments defined above or below, the process comprises a previous step comprising mixing vilanterol trifenatate with an appropriate amount of the ketone solvent and heating the mixture until dissolution.
In another particular embodiment of the process of the present disclosure, optionally in combination with one or more features of the particular embodiments defined above or below, the solution of the vilanterol trifenatate is a saturated solution.
In another embodiment, optionally in combination with one or more features of the particular embodiments defined above or below, the method of purification of vilanterol trifenatate further comprises recrystallizing vilanterol trifenatate from the same or a different solvent, the solvent being a ketone solvent selected from the group consisting of methyl ethyl ketone (MEK), methyl isobutyl ketone (MIK), ethyl isopropyl ketone, methyl isopropyl ketone, 3-methyl-2-pentanone, and a mixture thereof.
Said purification by recrystallization can be carried out according to methods known in the art, in particular, by dissolving vilanterol trifenatate at warm in at least one of the mentioned ketone solvents, and then cooling the resulting solution to precipitate the product. In a more particular embodiment, optionally in combination with one or more features of the particular embodiments defined above or below, the method comprises seeding with vilanterol trifenatate crystals to initiate the recrystallization. Vilanterol trifenatate crystals used for seeding can be obtained by any method known in the art, particularly by the crystallization and/or recrystallization methods of the present disclosure.
In a particular embodiment, recrystallization is carried out in MEK.
Particularly, the recrystallization of vilanterol trifenatate in MEK comprises:
In another particular embodiment, recrystallization is carried out in MIK as the ketone solvent.
Particularly, the recrystallization of vilanterol trifenatate in MIK comprises:
Additionally, in an attempt to further increase the purity of the final product, the inventors realized that by carrying out recrystallization of vilanterol trifenatate by Ostwald ripening using the mentioned ketone solvents, no aggregates are formed, as opposed to other solvents such as ethanol. Besides, the size of the crystals that are generated from the mentioned ketone solvents is more convenient when micronizing than the ones generated from ethanol.
Thus, in another embodiment, optionally in combination with one or more features of the particular embodiments defined above or below, recrystallization is carried out by Ostwald ripening. Particularly, Ostwald ripening comprises:
In a particular embodiment, Ostwald ripening is carried out in MEK and the method comprises the following steps:
In another particular embodiment, Ostwald ripening is carried out in MIK and the method comprises the following steps:
Throughout the description and claims the word “comprise” and variations of the word, are not intended to exclude other technical features, additives, components, or steps. Furthermore, the word “comprise” encompasses the case of “consisting of”.
The following examples and drawings are provided by way of illustration, and they are not intended to be limiting of the present invention. Furthermore, the present invention covers all possible combinations of particular and preferred embodiments described herein.
The HPLC analysis was carried out in the following column and conditions:
Vilanterol trifenatate was prepared according to the following reaction scheme:
As shown below, both vilanterol base (II) in solution and crystallized vilanterol trifenatate (I) contain a non-desirable amount of impurity A.
40,0 g (59,1 mmol) of compound (III) were stirred in a mixture of 253 mL of ACN and 355 mL of HCl 0.5 N (177.4 mmol, 3.0 eq.) at 4° C. for 48 h. Then, 344 mL of methylene chloride and 200 mL of K2CO3 20% were added and phases were separated. The aqueous phase was extracted with 130 mL of methylene chloride.
The resulting organic phase, comprising compound (II) (HPLC=98.44%) and impurity A (HPLC==0.45%), was divided into 4 equal parts (parts from 1 to 4). Each part was used in Examples 2 and 3, and Comparative Examples 1 and 2 below.
The solvent of part 1 obtained in Example 1 was distilled off at reduced pressure and swapped with methyl ethyl ketone (MEK). The obtained residue (compound (II)) was dissolved in 88 mL of MEK. 4.3 g (14.8 mmol, 1.0 eq) of solid triphenylacetic acid were added all at once. The solution was heated to 55° C. and cooled to 20-25° C. for 3 h. The white solid obtained was filtered and washed twice with 11 mL of MEK. The white solid was dried under reduced pressure at 20-25° C. for 16 h and under reduced pressure at 55° C. for 1 h. 9.2 g (11.9 mmol) of vilanterol trifenatate (I) were obtained (yield=80%) (HPLC=99.38%, Impurity A=0.19%).
The solvent of part 2 obtained in Example 1 was distilled off at reduced pressure and swapped with methyl isobutyl ketone (MIK). The obtained residue (compound (II)) was dissolved in 88 mL of MIK. 4.3 g (8 mmol, 1.0 eq) of solid triphenylacetic acid were added all at once. The solution was heated to 55° C. and cooled to 20-25° C. for 3 h. The white solid obtained was filtered and washed twice with 11 mL of MIK. The white solid was dried under reduced pressure at 20-25° C. for 16 h and under reduced pressure at 55° C. for 1 h. 10.4 g (13,4 mmol) of vilanterol trifenatate (I) were obtained (yield=91 %) (HPLC=99.28%, Impurity A=0.23%).
The solvent of part 3 obtained in Example 1 was distilled off at reduced pressure and swapped with acetone. The obtained residue (compound (II)) was dissolved in 88 mL of acetone. 4.3 g (14.8 mmol, 1.0 eq) of solid triphenylacetic acid were added all at once. The solution was heated to 55° C. and cooled to 20-25° C. for 3 h. The white solid obtained was filtered and washed twice with 11 mL of acetone. The white solid was dried under reduced pressure at 20-25° C. for 16 h and under reduced pressure at 55° C. for 1 h. 7,1 g (9.2 mmol) of vilanterol trifenatate (I) were obtained (yield=62%) (HPLC=99.47%, Impurity A=0.14%).
The solvent of part 4 obtained in Example 1 was distilled off at reduced pressure and swapped with ethanol. The obtained residue (compound (II)) was dissolved in 88 mL of ethanol. 4.3 g (14.8 mmol, 1.0 eq) of solid triphenylacetic acid were added all at once. The solution was heated to 55° C. and cooled to 20-25° C. for 3 h. The white solid obtained was filtered and washed twice with 11 mL of ethanol. The white solid was dried under reduced pressure at 20-25° C. for 16 h and under reduced pressure at 55° C. for 1 h. 9.3 g (12.0 mmol) of vilanterol trifenatate (I) were obtained (yield=81 %) (HPLC=99.11%, Impurity A=)0.28%.
Vilanterol trifenalate was obtained following Example 2. After being filtered and washed with MEK, the white solid was dried under reduced pressure at 20-25° C. for 16 h and under reduced pressure at 55° C. for 1 h. 36,3 g (46,8 mmol) of vilanterol trifenatate (I) were obtained (yield=79%) (HPLC=99,37%, Impurity A=0,18%).
9,0 g (11,6 mmol) of vilanterol trifenatate obtained in Example 4 were stirred at 20-25° C. with 72 mL of MEK. The suspension was heated at 55-60° C. until a solution was obtained. The solution was cooled to 50-55° C., seeded with vilanterol trifenatate crystals and cooled to 20-25° C. for 3 h. The white solid obtained was filtered and washed twice with 9 mL of MEK. The white solid was dried under reduced pressure at 55° C. for 16 h. 8,1 g (10,5 mmol) of vilanterol trifenatate (I) were obtained (yield= 90%) (HPLC=99,60%, Impurity A=0,08%).
9,0 g (11,6 mmol) of vilanterol trifenatate obtained in Example 4 were stirred at 20-25° C. with 270 mL of MIK. The suspension was heated at 65-67° C. until a solution is obtained. The solution was cooled to 60-62° C., seeded with vilanterol trifenatate crystals and cooled to 20-25° C. for 3 h. The white solid obtained was filtered and washed twice with 9 mL of MIK. The white solid was dried under reduced pressure at 55° C. for 16 h. 7,8 g (10,1 mmol) of vilanterol trifenatate (I) were obtained (yield= 87%) (HPLC=99,54%, Impurity A=0,09%).
9,0 g (11,6 mmol) of vilanterol trifenatate obtained in Example 4 were stirred at 20-25° C. with 90 mL of acetone. The suspension was heated at 55-56° C. until a solution was obtained. The solution was cooled to 50-52° C., seeded with vilanterol trifenatate crystals and cooled to 20-25° C. for 3 h. The white solid obtained was filtered and washed twice with 9 mL of acetone. The white solid was dried under reduced pressure at 55° C. for 16 h. 5,5 g (7,1 mmol) of vilanterol trifenatate (I) were obtained (yield= 61%) (HPLC=99,57%, Impurity A=0,09%).
9,0 g (11,6 mmol) of vilanterol trifenatate obtained in Example 4 were stirred at 20-25° C. with 90 mL of ethanol. The suspension was heated at 55-60° C. until a solution is obtained. The solution was cooled to 50-55° C., seeded with vilanterol trifenatate crystals and cooled to 20-25° C. for 3 h. The white solid obtained was filtered and washed twice with 9 mL of ethanol. The white solid was dried under reduced pressure at 55° C. for 16 h. 7,9 g (10,2 mmol) of vilanterol trifenatate (I) were obtained (yield= 88%) (HPLC=99,44%, Impurity A=0,17%).
Vilanterol trifenatate (100 g, 129 mmol) was suspended in MEK (850 mL). The suspension was heated to 55° C. until a solution was observed. Then, the system was cooled to 49° C., seeded with vilanterol trifenatate crystals and the following Ostwald ripening process was then followed:
The obtained suspension was cooled to 20° C. and stirred at this temperature for 1 h. The white solid obtained was filtered and dried under reduced pressure at 55° C. for 24 h. 88 g (114 mmol) of vilanterol trifenatate (I) were obtained (yield= 88%).
A SEM image of the crystals obtained is shown in
Vilanterol trifenatate (20 g, 25,8 mmol) was suspended in MIK (600 mL). The suspension was heated to 65-68° C. until a solution was observed. Then, the system was cooled to 57° C., seeded with vilanterol trifenatate crystals and the following Ostwald ripening process was then followed:
The obtained suspension was cooled to 20° C. and stirred at this temperature for 1 h. The white solid obtained was filtered and dried under reduced pressure at 55° C. for 16 h. 17 g (21,9 mmol) of vilanterol trifenatate (I) were obtained (yield= 85%).
A SEM image of the crystals obtained is shown in
Vilanterol trifenatate (20 g, 25,8 mmol) was suspended in ethanol (210 mL). The suspension was heated to 55-56° C. until a solution was observed. Then, the system was cooled to 49° C., seeded with vilanterol trifenatate crystals and the following Ostwald ripening process was then followed:
The obtained suspension was cooled to 10° C. and stirred at this temperature for 1 h. The white solid obtained was filtered and dried under reduced pressure at 55° C. for 16 h. 18 g (23,2 mmol) of vilanterol trifenatate (I) were obtained (yield= 90%).
A SEM image of the crystals obtained is shown in
Examples and Comparative Examples above carried out by Ostwald ripening show that, advantageously, no aggregates are formed from MEK or MIK, as opposed to ethanol, and that the size of the crystals that are generated from MEK or MIK is more adequate when micronizing than from ethanol.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20382677.1 | Jul 2020 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/070903 | 7/26/2021 | WO |
