Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
  • C07F5/00—Compounds containing elements of Groups 3 or 13 of the Periodic Table
  • C07F5/02—Boron compounds
  • C07F5/025—Boronic and borinic acid compounds

Definitions

• the invention relates to novel polymorphic forms of Ixazomib citrate of formula I, with the chemical name (R)-2,2'-(2-(1-(2-(2,5-dichlorobenzamido)acetamido)-3- methylbuty!)-5-oxo-1 ,3,2-dioxaborolan-4,4-diyl)diacetic acid:
• Ixazomib is a novel member of the group of proteasome inhibitors with a structure belonging to the group of peptidic boronic acids.
• a well-known and already commercially available member of this group is bortezomib of formula A.
• Bortezomib is used for the treatment of multiple myelomas.
• Ixazomib citrate is envisaged for the treatment of the same disease but, due to stabilization of the boronic acid in the form of a mixed ester-anhydride with citric acid, it will be possible to administer the substance also in the oral form.
• Boronic acids are sometimes difficult to prepare in the pure form. In conditions that are favourable for dehydration, boronic acids form cyclic anhydrides and are often sensitive to light. Therefore, boronic acids are advantageously stabilized with a complexing agent, e.g.
• Ixazomib citrate whose novel forms and process for the preparation are provided by this invention, also belongs to such stabilized compounds.
• Ixazomib citrate and a process for the preparation were first described in the patent application WO 2009/154737.
• Boroxine of formula III is reacted with citric acid in a solvent at an elevated temperature; after cooling, the crystallized product is isolated by filtering. If after the reaction of boroxine of formula HI with citric acid in ethyl acetate at 74°C uncontrolled cooling of the reaction mixture is conducted, this may lead to formation of the 5-membered isomeric Form 1 (meiting point 198.8°C), while controlled cooling of the reaction mixture to the room temperature or to 40°C results in formation of the more stable isomeric Form 2 (melting point 219.9°C).
• Form 2 can also be prepared through a reaction of the compound of formula 111 with citric acid and crystallization from various solvents (tetrahydrofuran, acetonitrile, methyl /so-butyl ketone, 2- methyltetrahydrofuran, acetone), followed by addition of the acetic acid ethyl ester as an antisolvent.
• various solvents tetrahydrofuran, acetonitrile, methyl /so-butyl ketone, 2- methyltetrahydrofuran, acetone
• the invention provides novel polymorphic forms - crystalline C2- C4 alcoholic solvate of Ixazomib citrate of isomeric Form 1 of formula I:
• Ixazomib citrate as the first proteasome inhibitor that can also be administered orally places high demands on stability of the given form. For this reason, as many stable forms of the given pharmaceutical substance - in this case Ixazomib citrate - as possible should be available.
• Both the solvates have crystallized in the monoclinic system with two molecules of Ixazomib citrate and two molecules of the solvent in the asymmetrical part of the cell ( Figures 3 and 4, Tables 3 and 4).
• Ixazomib citrate isopropanol In the structure of the Ixazomib citrate isopropanol solvate both the molecules of the solvent in the asymmetrical part of the cell were disordered with the occupancies of 0.666 : 0.334 and 0.696 : 0.304.
• novel crystalline forms of Ixazomib citrate of formula I are referred to as the ethanol solvate and isopropanol solvate.
• the single crystal X-ray diffraction (shown in Figs. 3, 3a and 4, 4a) also clearly illustrates the arrangement of the citrate, which corresponds to isomeric Form 1 , i.e. forming a 5-membered cycle with boron.
• This invention also provides processes for the production of the above mentioned forms of Ixazomib citrate.
• Preparation of the alcohol solvates of Ixazomib citrate of formula I comprises dissolution of Ixazomib citrate in an alcohol and subsequent crystallization from the solution of the compound in the alcohol.
• ethanol As a suitable alcohol, ethanol, or isopropanol us used.
• the crystallization is conducted at a temperature of 20 to 85°C.
• the crystallization is conducted at a temperature of 20 to 25°C.
• an antisolvent is used for the crystallization.
• n-hexane or ethyl acetate is used as the antisolvent.
• the prepared alcohol solvates are characterized by a different powder diffraction pattern from those of the hitherto known Forms 1 and 2 disclosed in the application WO 2009/154737 and Form 3.
• the ethanol solvate of Ixazomib citrate of formula la exhibits the following characteristic reflections in an X-ray powder pattern measured with the use of CuKa radiation: 6.0; 12.1 ; 14.4; 18.2; 22.4 and 24.4 ⁇ 0.2° 2-theta and more reflections, presented in Table 1.
• the isopropanol solvate of Ixazomib citrate of formula lb exhibits the following characteristic reflections in an X-ray powder pattern measured with the use of CuKa radiation: 6.2; 10.0; 14.5; 17.1 and 21.0 ⁇ 0.2° 2-theta and more reflections, presented in Table 2.
• Another aspect of this invention is provided by an amorphous form of Ixazomib citrate that was prepared by lyophilization of a freeze-dried solution of Ixazomib citrate in a suitable solvent.
• a suitable solvent is an alcohol.
• fert-butanol is used as the alcohol for the preparation of the amorphous form of Ixazomib citrate of formula I.
• Fig. 3 X-ray diffraction on a single crystal of Ixazomib citrate I ethanol solvate; for clarity just one half of the asymmetrical part of the cell is shown with displayed thermal oscillations and atom descriptions
• Fig. 4 - X-ray diffraction on a single crystal of Ixazomib citrate I isopropyl alcohol solvate; asymmetrical part of the cell with displayed thermal oscillations
• Fig. 4A - X-ray diffraction on a single crystal of Ixazomib citrate I isopropyl alcohol solvate; for clarity just one half of the asymmetrical part of the cell without the disorder is shown, with displayed thermal oscillations and atom descriptions
• Fig. 5 Comparison of the crystal structures of Ixazomib citrate of formula I isopropyl alcohol solvate (at the top) and Ixazomib citrate of formula I ethanol solvate (at the bottom) and their calculated powder diffraction patterns.
• Fig. 6 X-ray powder diffraction pattern of the amorphous form of Ixazomib citrate
• Fig. 7 DSC record of the amorphous form of Ixazomib citrate
• a 10mm mask and a 1/4° fixed anti-dispersion slit were used.
• the irradiated area of the sample is 10 mm, programmable divergence slits were used.
• the measurement was carried out with a flat sample applied onto a Si plate.
• Ixazomib citrate (Form 3), 25 mg was dissolved in 1 ml of ethanol in a hot state. During 48 hours, in the presence of hexane vapours Ixazomib citrate crystallizes in the ethanol solvate form.
• Ixazomib citrate (Form 2), 25 mg was dissolved in a mixture of 10 ml of ethyl acetate and 2 ml of ethanol in a hot state. During 20 hours, crystals of Ixazomib citrate are formed by slow spontaneous evaporation in the ethanol solvate form.
• the X-ray pattern is equal to the pattern of Example 1.
• ixazomib citrate (Form 3), 20 mg was dissolved in 1.5 ml of isopropanol in a hot state. During 20 hours, in the presence of hexane vapours Ixazomib citrate crystallizes in the isopropanol solvate form.
• Ixazomib citrate (Form 3) was dissolved in 15 ml of fe/f-butanol. After freeze-drying of the solution (the bath consisting of an ethanol/dry ice mixture; -70°C and subsequent lyophilization (3.5 Pa; 24 h) Ixazomib citrate was obtained in an amorphous form.
• Fig. 6 The X-ray pattern of the amorphous form is shown in Fig. 6 and its DSC record is in Fig. 7.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=55948765

Family Applications (1)

Country Status (3)

Families Citing this family (8)

Family Cites Families (3)

• 2015
  • 2015-04-15 CZ CZ2015-253A patent/CZ2015253A3/cs unknown
• 2016
  • 2016-04-14 EP EP16721061.6A patent/EP3283491A1/en not_active Withdrawn
  • 2016-04-14 WO PCT/CZ2016/000043 patent/WO2016165677A1/en not_active Ceased

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events