4-(4-{3-[4-CHLORO-3-(TRIFLUOROMETHYL)PHENYL]UREIDO}PHENOXY)-
N2-METHYLPYRIDINE-2-CARBOXAMIDE DIMETHYL SULPHOXIDE
SOLVATE
Field of the Invention
The present invention provides a dimethyl sulphoxide solvate of 4-(4-{3-[4-chloro-
3-(trifluoromethyl)phenyl]ureido}phenoxy)-N -methylpyridine-2-carboxamide, a process
for its preparation, a pharmaceutical composition comprising it and its use for the
treatment of cancer. The present invention also provides a novel HPLC method for the
identification, quantification and isolation of related substances of sorafenib.
Background of the Invention
2 4-(4-{3-[4-Chloro-3-(trifluoromethyl) phenyl]ureido}phenoxy)-N -
methylpyridine-2-carboxamide, having the structure as represented by Formula I
FORMULA I
is marketed in the United States as its tosylate salt (sorafenib tosylate) of Formula II
FORMULA II
under the brand name Nexavar for the treatment of patients with unresectable
hepatocellular carcinoma and advanced renal cell carcinoma.
WO 2006/034797 discloses ethanol and methanol solvates of sorafenib tosylate.
U.S. Patent Publication 2009/192200 discloses dimethyl sulphoxide and Nmethylpyrrolidone
solvates of sorafenib tosylate.
Summary of the Invention
The present invention provides safe and industrially advantageous dimethyl
sulphoxide solvate of sorafenib, process for its preparation, pharmaceutical composition
comprising it and its use for the treatment of cancer.
Sorafenib dimethyl sulphoxide solvate of the present invention is a free-flowing
non-hygroscopic solid and is stable towards heating up to a temperature of 110°C under
reduced pressure.
The present invention also provides processes for the preparation of sorafenib free
base and sorafenib acid addition salts and a novel and efficient HPLC method capable of
separating all related substances of sorafenib.
A first aspect of the present invention provides sorafenib dimethyl sulphoxide
solvate of Formula III
FORMULA III
characterized by X-ray diffraction peaks at d-spacing 5.20, 4.21, 4.16, 3.83 and 3.66 A.
A second aspect of the present invention provides a process for the preparation of
sorafenib dimethyl sulphoxide solvate of Formula III.
FORMULA III
comprising contacting sorafenib free base of Formula I
FORMULA I
with dimethyl sulphoxide.
A third aspect of the present invention provides process for the preparation of
sorafenib free base of Formula I
FORMULA I
comprising contacting sorafenib dimethyl sulphoxide solvate of Formula III
FORMULA III
with a solvent.
A fourth aspect of the present invention provides a process for the preparation of
sorafenib free base of Formula I
FORMULA I
comprising heating sorafenib dimethyl sulphoxide solvate of Formula III
FORMULA III
above 110°C.
A fifth aspect of the present invention provides a process for the preparation of
sorafenib acid addition salts of Formula IV
FORMULA IV
comprising contacting sorafenib dimethyl sulphoxide solvate of Formula III with an acid
of Formula HX and isolating sorafenib acid addition salt of Formula IV.
A sixth aspect of the present invention provides a pharmaceutical composition
comprising sorafenib dimethyl sulphoxide solvate of Formula III and one or more
pharmaceutically acceptable carriers, diluents or excipients.
A seventh aspect of the present invention provides use of sorafenib dimethyl
sulphoxide solvate of Formula III for the treatment of cancer.
An eighth aspect of the present invention provides an HPLC method for the
identification, quantification and isolation of related substances of sorafenib,
pharmaceutically acceptable salts, polymorphs, pseudomorphs and solvates thereof
comprising the use of a buffer and a single organic solvent as mobile phase.
A ninth aspect of the present invention provides sorafenib or pharmaceutically
acceptable salts, polymorphs, pseudomorphs and solvates thereof substantially free of
related substances determined by area percentage of HPLC.
Other objects, features, advantages and aspects of the present invention will
become apparent to those skilled in the art from the description provided herein.
Brief Description of the Figures
Figure 1: X-ray Diffraction (XRD) pattern of sorafenib dimethyl sulphoxide
solvate
Figure 2: Differential Scanning Calorimetry (DSC) thermogram of sorafenib
dimethyl sulphoxide solvate
Figure 3: Thermogravimetric Analysis (TGA) curve of sorafenib dimethyl
sulphoxide solvate
Figure 4: Infra-red (IR) spectrum of sorafenib dimethyl sulphoxide solvate
Figure 5: HPLC chromatogram of sorafenib dimethyl sulphoxide solvate
Figure 6: HPLC chromatogram of sorafenib free base to be used for the preparation
of sorafenib dimethyl sulphoxide solvate
Figure 7: HPLC chromatogram of sorafenib free base obtained by desolvation of
sorafenib dimethyl sulphoxide solvate
Figure 8: HPLC chromatogram of sorafenib tosylate
Figure 9: HPLC chromatogram of sorafenib free base
Figure 10: HPLC chromatogram of sorafenib tosylate
Detailed Description of the Invention
Various embodiments and variants of the present invention are described
hereinafter.
The term "related substance", as used herein, refers to any known or unknown
compound (impurity) present in the sample. A related substance may be introduced in the
sample as a process impurity or it may be formed due to degradation. Some related
substances may even be of unknown origin.
The term "sample", as used herein, refers to the material analyzed by any
analytical technique, including chromatography. It may consist of a single component or a
mixture of components. In the present invention, a sample may consist of sorafenib or
pharmaceutically acceptable salts, polymorphs, pseudomorphs, and solvates thereof.
The term "mobile phase", as used herein, refers to the solvent that moves the
sample through the column. The mobile phase used for the identification, quantification
or isolation of related substances of sorafenib may comprise a buffer and a single organic
solvent.
The buffer may be selected from acidic phosphate, citrate, formate or acetate
buffers, such as orthophosphoric acid or trifluoroacetic acid. Preferably, an acidic buffer,
such as orthophosphoric acid may be used.
The organic solvent to be used may be selected from the group consisting of
alcohols, alkyl acetates and alkyl nitriles. Examples of alcohols include methanol,
ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol, n-pentanol, ethylene
glycol and propylene glycol. Examples of alkyl acetates include methyl acetate, ethyl
acetate, propyl acetate and butyl acetate. Examples of nitriles include acetonitrile and
propionitrile. Preferably, alcohols, such as methanol, ethanol, n-propanol, isopropanol, nbutanol,
sec-butanol, isobutanol, n-pentanol, ethylene glycol or propylene glycol are used.
The term "retention time", as used herein, refers to the characteristic time taken by
a particular sample to pass through the system (from the column inlet to the detector)
under a set of conditions.
The term "relative retention time", as used herein, refers to the ratio between the
retention time of a related substance and that of sorafenib.
The term "substantially free of related substances determined by area percentage of
HPLC", as used herein, refers to sorafenib, pharmaceutically acceptable salts, polymorphs,
pseudomorphs and solvates thereof having no detectable amount of related substances 4-
(2-(N-methylcarbamonyl)-4-(pyridyloxy)aniline, 4-chloro-N-methyl-2-
pyridinecarboxamide and 4-chloro-3-(trifluoromethyl)phenyl isocyanate as determined by
area percentage of HPLC at relative retention time of 0.50, 0.64 and 0.88 minutes,
respectively.
The term "contacting" may include dissolving, slurrying, stirring or a combination
thereof.
Sorafenib dimethyl sulphoxide solvate of Formula III may be characterized by Xray
diffraction peaks at about 17.04 (d-spacing at 5.20 A), 21.05 (4.21 A), 21.34 (4.16 A),
23.19 (3.83 A) and 24.28 (3.66 A) + 0.2 degrees 2Q. It may be further characterized by Xray
diffraction peaks at about 16.52 (5.36 A), 19.85 (4.47 A), 19.98 (4.44 A), 27.30 (3.26
A) and 28.34 (3.14 A) + 0.2 degrees 2Q. It may also be characterized by a DSC
thermogram having endotherms at about 123.69°C and about 202.54°C. Sorafenib
dimethyl sulphoxide solvate of Formula III may also be characterized by its XRD pattern,
DSC thermogram, TGA curve and IR spectrum as depicted in Figure 1, 2, 3 and 4,
respectively. Table- 1 summarizes the d-spacing in A and the corresponding 2Qvalues of
sorafenib dimethyl sulphoxide solvate of Formula III. Sorafenib dimethyl sulphoxide of
Formula III may have a moisture content of about 0.1% by Karl-Fischer method.
Table 1: X-ray Diffraction Peaks of Sorafenib Dimethyl Sulphoxide Solvate
Position (°2Q) d-spacing (A) Relative Intensity ( )
6.80 13.01 1.89
8.48 10.43 7.97
9.34 9.47 1.58
10.21 8.66 2.10
11.42 7.75 9.78
12.22 7.24 8.49
12.70 6.97 12.27
15.64 6.49 11.70
13.87 6.38 19.62
14.06 6.30 23.66
14.94 5.93 10.52
15.46 5.73 18.35
15.62 5.67 17.16
16.52 5.36 29.12
17.04 5.20 49.13
17.82 4.98 24.11
18.74 4.73 21.67
19.09 4.65 12.73
19.36 4.59 11.21
19.64 4.52 14.14
19.85 4.47 36.50
19.98 4.44 35.03
20.52 4.33 25.78
20.79 4.27 20.54
21.05 4.21 65.56
21.34 4.16 68.00
23.19 3.83 52.91
24.17 3.68 74.03
24.28 3.66 100.00
24.78 3.59 25.64
25.18 3.54 15.20
25.60 3.48 15.16
25.89 3.44 17.19
26.47 3.37 16.35
27.30 3.26 28.72
27.96 3.19 8.68
28.34 3.14 26.78
28.76 3.10 11.90
29.26 3.05 12.59
29.52 3.03 7.51
29.86 2.99 5.68
31.00 2.88 5.36
31.49 2.84 9.73
32.30 2.77 5.55
Position (°2Q) d-spacing (A) Relative Intensity ( )
33.06 2.71 3.59
33.81 2.65 7.96
34.64 2.59 4.76
36.20 2.48 5.17
38.06 2.36 7.31
38.76 2.32 6.13
Sorafenib free base to be used for the preparation of sorafenib dimethyl sulphoxide
solvate of Formula III may be obtained by any of the methods known in the literature such
as those described in PCT applications WO 00/42012, WO 2006/034796, WO
2009/034308 and WO 2009/054004, which are incorporated herein by reference.
In general, sorafenib free base to be used for the preparation of sorafenib dimethyl
sulphoxide solvate may be prepared by the reaction of 4-(2-(N-methylcarbamoyl)-4-
pyridyloxy) aniline with 4-chloro-3-(trifluoromethyl)phenyl isocyanate. The starting
sorafenib freebase may be obtained as a solution directly from a reaction in which it is
formed and used as such without isolation.
Sorafenib free base of Formula I may be contacted with dimethyl sulphoxide at a
temperature of about 15°C to the reflux temperature of dimethyl sulphoxide. In
experiments involving contacting sorafenib free base with dimethyl sulphoxide at room
temperature, the reaction mixture may be stirred for about 2 hours to about 8 hours. In
experiments involving contacting sorafenib free base with dimethyl sulphoxide at a
temperature above room temperature, the reaction mixture may be stirred for about 5
minutes to about 30 minutes, slowly cooled to a temperature of 20°C to about 25°C in
about 5 minutes to about 30 minutes followed by further stirring for about 1 hour to about
10 hours.
Isolation may be accomplished by concentration, precipitation, cooling, filtration
or centrifugation, preferably by precipitation and filtration. The filtered material may be
optionally washed with water and dried at a temperature of about 40°C to about 65°C, for
about 30 minutes to about 24 hours. Any suitable method of drying may be employed
such as drying under reduced pressure, vacuum tray drying, air drying or a combination
thereof.
In one embodiment, sorafenib dimethyl sulphoxide solvate of Formula III may be
prepared by adding dimethyl sulphoxide to sorafenib free base of Formula I, stirring the
reaction mixture at a temperature of about 35°C to about 80°C, for about 5 minutes to
about 30 minutes, cooling the solution to a temperature of about 20°C to about 35°C in
about 5 minutes to about 30 minutes, stirring the reaction mixture for about 1 hour to
about 2 hours and isolating sorafenib dimethyl sulphoxide solvate. In a preferred
embodiment, sorafenib dimethyl sulphoxide solvate of Formula III may be prepared by
adding dimethyl sulphoxide to sorafenib free base of Formula I, stirring the reaction
mixture at about 45°C for about 10 minutes, cooling the solution to a temperature of about
25°C in about 15 minutes, stirring the reaction mixture for about 2 hours and isolating
sorafenib dimethyl sulphoxide solvate. In another preferred embodiment, sorafenib
dimethyl sulphoxide solvate of Formula III may be prepared by adding dimethyl
sulphoxide to sorafenib free base of Formula I, stirring the reaction mixture at about 60°C
for about 20 minutes, cooling the reaction mixture to about 25°C in about 15 minutes,
stirring for about 8 hours and isolating sorafenib dimethyl sulphoxide solvate.
In another embodiment, sorafenib dimethyl sulphoxide solvate of Formula III may
be prepared by adding dimethyl sulphoxide to sorafenib free base of Formula I at room
temperature, stirring the reaction mixture for about 1 hour to about 8 hours and isolating
sorafenib dimethyl sulphoxide solvate.
Sorafenib dimethyl sulphoxide solvate of Formula III has HPLC purity greater than
99%. In one embodiment, the HPLC purity is greater than 99.4%. In another
embodiment, the HPLC purity is greater than 99.7%.
The term "thermally stable sorafenib dimethyl sulphoxide solvate of Formula III",
as used herein, refers to sorafenib dimethyl sulphoxide solvate of Formula III stable
towards heating, to a temperature up to 110°C, in a vacuum oven. Preferably, sorafenib
dimethyl sulphoxide solvate of Formula III of the present invention is stable towards
heating in the temperature range of about 45°C up to 110°C for about 3 hours to about 4
hours in a vacuum oven. Desolvation of sorafenib dimethyl sulphoxide solvate to
sorafenib free base may occur on heating at a temperature of about 120°C to about 135°C.
Sorafenib dimethyl sulphoxide solvate of the present invention is a free-flowing
non-hygroscopic powder.
Sorafenib free base of Formula I may be prepared from sorafenib dimethyl
sulphoxide solvate of Formula III by contacting sorafenib dimethyl sulphoxide solvate
with a solvent at a temperature of about -5°C to the reflux temperature of the solvent. The
solvent is selected from the group consisting of water, chlorinated hydrocarbons, alcohols,
ketones, alkyl acetates, ethers and mixtures thereof. Examples of chlorinated
hydrocarbons include dichloromethane and chloroform. Examples of alcohols include
methanol, ethanol, iso-propanol and butanol. Examples of ketones include acetone,
dimethyl ketone, ethyl methyl ketone and methyl iso-butyl ketone. Examples of alkyl
acetates include methyl acetate, ethyl acetate, propyl acetate and butyl acetate. Examples
of ethers include diethyl ether, ethyl methyl ether, tetrahydrofuran and 1, 4-dioxane.
Precipitation of sorafenib free base from the reaction mixture of sorafenib dimethyl
sulphoxide solvate in a solvent may be spontaneous or it may occur after stirring the
reaction mixture for about 1 hour to about 8 hours.
In a particular embodiment, sorafenib free base of Formula I may be prepared by
contacting sorafenib dimethyl sulphoxide solvate of Formula III with water at room
temperature. The reaction mixture may be optionally heated to a temperature of about
40°C or above. The reaction mixture may be stirred for about 2 hours to about 24 hours.
In a preferred embodiment, sorafenib free base of Formula I may be prepared by
contacting sorafenib dimethyl sulphoxide solvate of Formula III with water at room
temperature, heating the reaction mixture to about 75°C and stirring the reaction mixture
for about 4 hours. In another preferred embodiment, sorafenib free base of Formula I may
be prepared by contacting sorafenib dimethyl sulphoxide solvate of Formula III with water
at room temperature and stirring the reaction mixture for about 17 hours.
In another embodiment, sorafenib free base of Formula I may be prepared by
contacting sorafenib dimethyl sulphoxide solvate of Formula III with a chlorinated
hydrocarbon solvent at a temperature of about -10°C to about +10°C and stirring the
reaction mixture for about 5 minutes to about 1 hour. In a preferred embodiment,
sorafenib free base of Formula I may be prepared by contacting sorafenib dimethyl
sulphoxide solvate of Formula III with a chlorinated hydrocarbon solvent at a temperature
of about 0°C and stirring the reaction mixture for about 15 minutes to about 1 hour. The
chlorinated hydrocarbon solvent may be selected from dichloromethane or chloroform,
preferably dichloromethane.
In another embodiment, sorafenib free base of Formula I may be prepared by
contacting sorafenib dimethyl sulphoxide solvate of Formula III with an alcohol at room
temperature and stirring the reaction mixture for about 1 hour to about 8 hours, preferably
for about 3 hours to about 4 hours. The alcohol may be selected from methanol, ethanol,
iso-propanol or butanol.
In another embodiment, sorafenib free base of Formula I may be prepared by
contacting sorafenib dimethyl sulphoxide solvate of Formula III with a ketone solvent at
room temperature and stirring the reaction mixture for about 1 hour to about 8 hours,
preferably for about 3 hours to about 4 hours. The ketone solvent may be selected from
acetone, dimethyl ketone, ethyl methyl ketone or methyl iso-butyl ketone.
In another embodiment, sorafenib free base of Formula I may be prepared by
contacting sorafenib dimethyl sulphoxide solvate of Formula III with an alkyl acetate
solvent at room temperature and stirring the reaction mixture for about 1 hour to about 8
hours, preferably for about 3 hours to about 4 hours. The alkyl acetate may be selected
from methyl acetate, ethyl acetate, propyl acetate or butyl acetate. Preferably, methyl
acetate or ethyl acetate may be used.
In another embodiment, sorafenib free base of Formula I may be prepared by
contacting sorafenib dimethyl sulphoxide solvate of Formula III with ether and stirring the
reaction mixture at room temperature for about 30 minutes to about 8 hours, preferably for
about 3 hours to about 4 hours. The ether may be selected from diethyl ether, ethyl methyl
ether, tert-butyl methyl ether, tetrahydrofuran or 1,4-dioxane, preferably tert-butyl methyl
ether.
Sorafenib free base of Formula I may also be obtained by heating sorafenib
dimethyl sulphoxide solvate of Formula III to a temperature of above 110°C, in a vacuum
oven. Heating may be carried out for about 1 hour to about 10 hours, preferably for about
4 hours.
In a particular embodiment, sorafenib free base of Formula I may be obtained by
heating sorafenib dimethyl sulphoxide solvate of Formula III to a temperature of about
120°C in a vacuum oven. In another embodiment, sorafenib free base of Formula I may
be obtained by heating sorafenib dimethyl sulphoxide solvate of Formula III to a
temperature of about 135°C in a vacuum oven.
The processes of the present invention provide sorafenib free base of HPLC purity
greater than 99%, preferably greater than 99.5%, more preferably about 99.9%.
Sorafenib acid addition salts of Formula IV may be prepared from sorafenib
dimethyl sulphoxide solvate of Formula III by contacting sorafenib dimethyl sulphoxide
solvate of Formula III with an acid of Formula HX. The acid of Formula HX may be
selected from the group consisting of hydrochloric acid, hydrobromic acid, sulfuric acid,
phosphoric acid, methanesulphonic acid, ethane sulphonic acid, trifluoromethanesulfonic
acid, benzenesulfonic acid, p-toluene sulphonic acid, 1-naphthalenesulfonic acid, 2-
naphthalenesulfonic acid, acetic acid, trifluoroacetic acid, malic acid, tartaric acid, citric
acid, lactic acid, oxalic acid, succinic acid, fumaric acid, maleic acid, benzoic acid,
salicylic acid, phenylacetic acid and mandelic acid.
The preparation of sorafenib acid addition salts of Formula IV may be carried out
using solvent(s) selected from the group consisting of water, organic solvents containing at
least one hydroxyl group, cyclic ethers, alkyl acetates, ketones, amides, nitriles,
sulphoxides and mixtures thereof. Examples of organic solvents containing at least one
hydroxyl group include methanol, ethanol, n-propanol, isopropanol, n-butanol, secbutanol,
isobutanol, n-pentanol, glycerol and ethylene glycol. Examples of cyclic ethers
include tetrahydrofuran and 1, 4-dioxane. Examples of alkyl acetates include methyl
acetate, ethyl acetate, propyl acetate and butyl acetate. Examples of ketones include
acetone, methyl ethyl ketone and methyl isobutyl ketone. Examples of amides include N,
N-dimethylformamide and N, N-dimethylacetamide. Examples of nitriles include
acetonitrile and propionitrile. Examples of sulphoxides include dimethyl sulfoxide and
diethyl sulphoxide.
The acid of Formula HX may be added in a period of about 5 minutes to about 30
minutes. The reaction mixture may be stirred at a temperature of about 15°C to the reflux
temperature of the solvent for about 8 hours to about 16 hours.
In a particular embodiment, sorafenib tosylate of Formula II may be prepared by
contacting sorafenib dimethyl sulphoxide solvate of Formula III with p-toluene sulphonic
acid. Both anhydrous and hydrated forms of p-toluene sulphonic acid may be used.
Preferably, p-toluene sulphonic acid monohydrate may be used.
p-Toluene sulphonic acid may be added to the reaction mixture containing
sorafenib dimethyl sulphoxide solvate in a solvent as a solid or a solution of p-toluene
sulphonic acid in water may be added.
In a particular embodiment, a solution of p-toluene sulphonic acid monohydrate in
water may be added to the reaction mixture containing sorafenib dimethyl sulphoxide
solvate in water or an organic solvent containing at least one hydroxyl group, such as
methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol, n-pentanol,
glycerol or ethylene glycol, preferably in water.
In another embodiment, sorafenib tosylate of Formula IV may be prepared by
adding a solution of p-toluene sulphonic acid monohydrate in water to a suspension of
sorafenib dimethyl sulphoxide solvate in water over a period of about 5 minutes to about
15 minutes and stirring the reaction mixture at about 60°C to about 100°C, preferably at
about 80°C, for about 8 hours to about 16 hours, preferably for about 12 hours.
In another embodiment, sorafenib tosylate of Formula IV may be prepared by
adding a solution of p-toluene sulphonic acid in water to a suspension of sorafenib
dimethyl sulphoxide solvate in water over a period of about 5 minutes to about 15 minutes
and stirring the reaction mixture at room temperature for about 8 hours to about 16 hours,
preferably for about 12 hours.
In the experiments involving preparation of sorafenib acid addition salts of
Formula IV from sorafenib dimethyl sulphoxide solvate of Formula III, sorafenib free base
may be optionally isolated from the reaction mixture.
The processes of the present invention provides sorafenib tosylate having HPLC
purity greater than 99%, preferably greater than 99.5%, more preferably greater than
99.8%.
Polymorphs and pseudomorphs of sorafenib dimethyl sulphoxide solvate of
Formula III are also included within the scope of the present invention.
Sorafenib dimethyl sulphoxide solvate of Formula III may be administered as part
of a pharmaceutical composition for the treatment of cancer. Accordingly, in a further
aspect, there is provided a pharmaceutical composition comprising sorafenib dimethyl
sulphoxide solvate of Formula III and one or more pharmaceutically acceptable carriers,
diluents or excipients and optionally other therapeutic ingredients. Pharmaceutical
compositions comprising sorafenib dimethyl sulphoxide solvate of Formula III may be
administered orally, topically, parenterally, by inhalation or spray, rectally or in the form
of injectables. The injectable compositions may include intravenous, intramuscular,
subcutaneous and parenteral injections, as well as, use of infusion techniques.
The HPLC method of the present invention is advantageous as it can be used for
the identification and quantification of a wide range of related substances of sorafenib, for
reaction monitoring and for determining chromatographic purity of sorafenib or
pharmaceutically acceptable salts, polymorphs, pseudomorphs and solvates thereof.
Additionally, the HPLC method of the present invention has the following advantages:
Easy set-up.
Less time-consuming.
Results are reproducible.
Involves use of an acidic buffer and does not involve use of any salts due to
which HPLC column can be used for a longer time. Thus, the method is
instrument-friendly.
Does not require any pH adjustment.
In the foregoing section, embodiments are described by way of examples to
illustrate the processes of invention. However, these are not intended in any way to limit
the scope of the present invention. Several variants of the examples would be evident to
persons ordinarily skilled in the art which are within the scope of the present invention.
Methods
The HPLC method of the present invention is described as follows:
A) Reagents, Solvents and Standards:
Water (HPLC Grade)
Orthophosphoric acid (88%, AR Grade)
Methanol (HPLC Grade)
Chromatographic Conditions:
Column: Zorbax SB AQ, 250 mm x 4.6 mm, 5m
Flow rate: 1.0 mL/ minute
Detector: UV at 260 nm
Injection volume: 10 mΐ
Column oven Temperature: 30°C
Run time: 50 minutes
Buffer: Orthophosphoric acid in water
Mobile Phase: Buffer and Methanol
Diluent: Pre-mixed and degassed solution of buffer and methanol (40:60; v/v)
Gradient
Time Methanol Buffer
0 10 90
5 10 90
35 85 15
40 85 15
43 10 90
50 10 90
C) Preparation of Buffer
1mL of orthrophosphoric acid was transferred into a volumetric flask. Water
(1000 mL) was added. The contents were mixed thoroughly and filtered through 0.45
micron or finer porosity membrane filter.
D) Preparation of Diluent
A pre-mixed and degassed solution of buffer and methanol in the ratio of 40:60
(v/v) was used as a diluent.
E) Preparation of Standard Solution
25 mg of accurately weighed sorafenib tosylate working standard was transferred
into a 200 mL volumetric flask. Methanol (3 mL) was added and the contents were
sonicated till complete dissolution takes place. 5 mL of this solution was diluted to 50 mL
by adding diluent. 5 mL of the resultant solution was further diluted to 25 mL by adding
diluent. The final solution was filtered through 0.45 micron nylon filter.
F) Preparation of Sample Solution
25 mg of accurately weighed sorafenib tosylate was transferred to a 200 mL
volumetric flask. Methanol (3 mL) was added and the contents were sonicated till
complete dissolution takes place. The volume was made up by adding diluent. The
resultant solution was filtered through 0.45 micron nylon filter.
G) Preparation of Blank
Methanol (3 mL) was transferred to a 50 mL volumetric flask and the volume was
made up by adding diluent.
H) Evaluation of System Suitability
The standard solution was injected into the chromatograph for recording the
chromatogram. The system was considered to be suitable for analysis only if the following
conditions were met:
USP tailing factor of peak corresponding to sorafenib was not more than 1.5.
Percentage RSD of five replicate injections of standard solutions was not
more than 2%.
I) Procedure
After system suitability evaluation, chromatograms were recorded by separately
injecting blank and sample solution into the chromatograph. The blank chromatogram
was examined for any extraneous peaks to disregard the corresponding peaks observed in
the chromatogram of the sample solution.
The retention times (RT) and relative retention times (RRT), in minutes, for the
compounds resolved using the HPLC method of the present invention is provided below:
Compound RT RRT
4-(2-(N-methylcarbamonyl)-4-(pyridyloxy) aniline 18.32 0.50
4-chloro-N-methyl-2-pyridinecarboxamide 23.21 0.64
4-chloro-3-(trifluoromethyl) phenyl isocyanate 32.00 0.88
Sorafenib 36.38 1.0
X-ray diffraction patterns were recorded using Panalytical Expert PRO with
Xcelerator as detector, 3-40 as scan range, 0.02 as step size and 3-40° 2Qas range.
DSC and TGA were recorded using Mettler Toledo DSC 82l e and TA instrument
e 500, respectively.
Moisture content was measured by Karl-Fischer method
Examples
Non-limiting examples of the present invention are as follows.
Example 1: Preparation of Sorafenib Free Base
A solution of 4-chloro-3-(trifluoromethyl)phenyl isocyanate (101.1 g) in
dichloromethane (250 mL) was added to a reaction mixture containing 4-(2-(Nmethylcarbamoyl)-
4-pyridyloxy)aniline (110.0 g) in dichloromethane (250 mL) at about
0°C in about 30 minutes. The reaction mixture was stirred at room temperature for about
16 hours. The resulting solid was filtered, washed with dichloromethane (2 x 200 mL) and
dried under reduced pressure at about 35°C for about 4 hours to obtain sorafenib free base.
Yield: 52.3%; HPLC Purity: 97.86%
Example 2: Preparation of Sorafenib Dimethyl Sulphoxide Solvate
Method A:
A reaction mixture containing sorafenib free base (10 g) in dimethyl sulphoxide
(15 mL) was stirred at about 45°C for about 10 minutes. The solution was slowly cooled
to about 25°C in about 15 minutes. The solution was stirred for about 2 hours. The
resulting solid was filtered, washed with water (3 x 20 mL) and dried under reduced
pressure at about 50°C for about 5 hours to obtain sorafenib dimethyl sulphoxide solvate.
Yield: 68%; HPLC purity: 99.43%
Method-B:
A reaction mixture containing sorafenib free base (40 g) in dimethyl sulphoxide
(15 mL) was stirred at about 60°C for about 20 minutes. The solution was slowly cooled
to about 25°C in about 20 minutes. The solution was stirred for about 8 hours. The
resulting solid was filtered and dried under reduced pressure at about 50°C for about 12
hours to obtain sorafenib dimethyl sulphoxide solvate.
Yield: 81.3%; HPLC purity: 99.75%
Method C:
A reaction mixture containing sorafenib free base (12 g) in dimethyl sulphoxide
(18 mL) was stirred at room temperature for about 5 hours. The resulting solid was
filtered, washed with water (2 x 20 mL) and dried at about 45°C for about 12 hours in an
air oven to obtain sorafenib dimethyl sulphoxide solvate.
Yield: 74.9 %
Example 3: Preparation of Sorafenib Free Base By Desolvation of Sorafenib Dimethyl
Sulphoxide Solvate in Different Solvents
Method A:
Water (10 mL) was added to sorafenib dimethyl sulphoxide solvate ( 1 g) at room
temperature. The reaction mixture was stirred at about 75°C for about 4 hours. The
resulting solid was filtered and dried under reduced pressure at about 45°C for about 4
hours to obtain sorafenib free base.
Yield: 75.9%
Method B:
Water (10 mL) was added to sorafenib dimethyl sulphoxide solvate ( 1 g) at room
temperature. The reaction mixture was stirred for about 17 hours. The resulting solid was
filtered and dried under reduced pressure at about 40°C for about 4 hours to obtain
sorafenib free base.
Yield: 84.1%
Method C:
Dichloromethane (10 mL) was added to sorafenib dimethyl sulphoxide solvate (1
g) at a temperature of about 0°C. The reaction mixture was stirred for about 15 minutes to
obtain a solution. The solution was stirred for about 10 minutes. The resulting solid was
filtered and dried under reduced pressure at about 40°C for about 1 hour to obtain
sorafenib free base.
Yield: 93.5%; HPLC purity: 99.78%
Method D:
Methanol (10 mL) was added to sorafenib dimethyl sulphoxide solvate ( 1 g) at
room temperature. The reaction mixture was stirred. The resulting solid started appearing
after about 5 minutes. The reaction mixture was stirred for about 4 hours, filtered and
dried under reduced pressure at about 45°C for about 5 hours to obtain sorafenib free base.
Yield: 87.6%; HPLC Purity: 99.79%
Method E:
Ethanol (10 mL) was added to sorafenib dimethyl sulphoxide solvate ( 1 g) at room
temperature. The reaction mixture was stirred. A solid started appearing after about 5
minutes. The reaction mixture was stirred for about 4 hours, filtered and dried under
reduced pressure at about 45°C for about 5 hours to obtain sorafenib free base.
Yield: 76.4%; HPLC Purity: 99.81%
Method F:
Iso-propanol (10 mL) was added to sorafenib dimethyl sulphoxide solvate ( 1 g) at
room temperature. The reaction mixture was stirred for about 4 hours. The reaction
mixture was filtered and dried under reduced pressure at about 45°C for about 4 hours to
obtain sorafenib free base.
Yield: 52.5%; HPLC Purity: 99.82%
Method G:
Acetone (10 mL) was added to sorafenib dimethyl sulphoxide solvate ( 1 g) at room
temperature. The reaction mixture was stirred. A solid started appearing after about 5
minutes. The reaction mixture was stirred for about 4 hours, filtered and dried under
reduced pressure at about 40°C for about 4 hours to obtain sorafenib free base.
Yield: 58.4%
Method H:
Methyl acetate (15 mL) was added to sorafenib dimethyl sulphoxide solvate (1.5 g)
at room temperature. The suspension was stirred for about 4 hours, filtered and dried
under reduced pressure at about 45°C for about 4 hours to obtain sorafenib free base.
Yield: 28.9 %; HPLC Purity: 99.73%
Method I :
Ethyl acetate (10 mL) was added to sorafenib dimethyl sulphoxide solvate (1.5 g)
at room temperature. The suspension was stirred for about 4 hours, filtered and dried
under reduced pressure at about 45°C for about 4 hours to obtain sorafenib free base.
Yield: 34.4%; HPLC Purity: 99.9%
Method J :
Methyl ethyl ketone (15 mL) was added to sorafenib dimethyl sulphoxide solvate
(1.5 g) at room temperature. The reaction mixture was stirred. A solid started appearing
after about 5 minutes. The reaction mixture was stirred for about 4 hours, filtered and
dried under reduced pressure at about 45°C for about 4 hours to obtain sorafenib free base.
Yield: 51.4%; HPLC Purity: 99.74%
Method K:
Methyl iso-butyl ketone (15 mL) was added to sorafenib dimethyl sulphoxide
solvate (1.5 g) at room temperature. The reaction mixture was stirred. A solid started
appearing after about 5 minutes. The reaction mixture was stirred for about 4 hours,
filtered and dried under reduced pressure at about 45°C for about 4 hours to obtain
sorafenib free base.
Yield: 57.4%; HPLC Purity: 99.88%
Example 4: Preparation of Sorafenib Free Base by Heating Sorafenib Dimethyl
Sulphoxide Solvate
Sorafenib dimethyl sulphoxide solvate (7 g) was divided into seven equal portions
and each portion was kept at a different temperature for about 4 hours in a vacuum oven.
No change was observed on heating for about 4 hours in the temperature range of about
45°C up to 110°C in a vacuum oven. Desolvation of sorafenib dimethyl sulphoxide solvate
to sorafenib free base was observed on heating to a temperature of about 120°C and about
135°C for about 4 hours in a vacuum oven.
Example 5: Preparation of Sorafenib Tosylate
Method A:
Water (10 mL) was added to sorafenib dimethyl suphoxide solvate (2 g). The
reaction mixture was stirred for about 5 minutes. A solution of p-toluene sulphonic acid
monohydrate (1.41 g) in water (10 mL) was added in a period of about 10 minutes to the
above reaction mixture. The resulting reaction mixture was stirred for about 12 hours at
about 80°C to obtain a solid, washed with water (2 x 10 mL) and dried under reduced
pressure at about 50°C for about 5 hours to obtain sorafenib tosylate.
Yield: 89.3%; HPLC Purity: 99.81%
Method B:
Water (5 mL) was added to sorafenib dimethyl suphoxide solvate (1 g). The
reaction mixture was stirred for about 5 minutes. A solution of p-toluene sulphonic acid
monohydrate (1.41 g) in water (5 mL) was added in a period of about 10 minutes to the
above reaction mixture. The resulting reaction mixture was stirred for about 12 hours at
room temperature to obtain a solid, washed with water (2 x 10 mL) and dried under
reduced pressure at about 45°C for about 5 hours to obtain sorafenib tosylate.
Yield: 82%; HPLC Purity: 99.71%
We claim:
1. Sorafenib dimethyl sulphoxide solvate of Formula III
FORMULA III
characterized by X-ray diffraction peaks at d-spacing 5.20, 4.21, 4.16, 3.83 and 3.66 A.
2. Sorafenib dimethyl sulphoxide solvate according to claim 1 further characterized
by X-ray diffraction peaks at d-spacing 5.36, 4.47, 4.44, 3.26 and 3.14 A.
3. Sorafenib dimethyl sulphoxide solvate of Formula III characterized by X-ray
diffraction pattern as depicted in Figure 1.
4. Sorafenib dimethyl sulphoxide solvate of Formula III characterized by DSC
thermogram having endotherms at about 123.69°C and about 202.54°C.
5. Sorafenib dimethyl sulphoxide solvate of Formula III characterized by DSC
thermogram as depicted in Figure 2.
6. Sorafenib dimethyl sulphoxide solvate of Formula III characterized by X-ray
diffraction pattern as depicted in Figure 1 and DSC thermogram as depicted in Figure 2.
7. Sorafenib dimethyl sulphoxide solvate of Formula III characterized by TGA as
depicted in Figure 3.
8. Sorafenib dimethyl sulphoxide solvate of Formula III characterized by IR spectrum
as depicted in Figure 4.
9. Sorafenib dimethyl sulphoxide solvate of Formula III having purity greater than
99% by HPLC.
10. A process for the preparation of sorafenib dimethyl sulphoxide solvate of Formula
III
FORMULA III
comprising contacting sorafenib free base of Formula I
FORMULA I
with dimethyl sulphoxide.
11. The process according to claim 10, wherein Sorafenib free base of Formula I is
contacted with dimethyl sulphoxide at a temperature of about 15°C to the reflux
temperature of dimethyl sulphoxide.
12. A process for the preparation of sorafenib free base of Formula I
FORMULA I
comprising contacting sorafenib dimethyl sulphoxide solvate of Formula III
FORMULA III
with a solvent.
13. The process according to claim 12, wherein the solvent is selected from the group
consisting of water, chlorinated hydrocarbons, alcohols, ketones, alkyl acetates, ethers and
mixtures thereof.
14. The process according to claim 12, wherein sorafenib dimethyl sulphoxide solvate
of Formula III is contacted with a solvent at a temperature of about -5°C to the reflux
temperature of the solvent.
15. A process for the preparation of sorafenib free base of Formula I
FORMULA I
comprising heating sorafenib dimethyl sulphoxide solvate of Formula III
FORMULA III
110°C.
A process for the preparation of sorafenib acid addition salts of Formula IV
FORMULA IV
comprising contacting sorafenib dimethyl sulphoxide solvate of Formula III with an acid
of Formula HX and isolating sorafenib acid addition salt of Formula IV.
17. The process according to claim 16, wherein the acid of Formula HX is selected
from the group consisting of hydrochloric acid, hydrobromic acid, sulfuric acid,
phosphoric acid, methanesulphonic acid, ethane sulphonic acid, trifluoromethanesulfonic
acid, benzenesulfonic acid, p-toluene sulphonic acid, 1-naphthalenesulfonic acid, 2-
naphthalenesulfonic acid, acetic acid, trifluoroacetic acid, malic acid, tartaric acid, citric
acid, lactic acid, oxalic acid, succinic acid, fumaric acid, maleic acid, benzoic acid,
salicylic acid, phenylacetic acid and mandelic acid.
18. The process according to claim 16, wherein sorafenib dimethyl sulphoxide solvate
of Formula III is contacted with an acid of Formula HX in a solvent selected from the
group consisting of water, organic solvents with 1-6 carbon atoms containing at least one
hydroxyl group, cyclic ethers, alkyl acetates, ketones, amides, nitriles, sulphoxides, and
mixtures thereof.
19. The process according to claim 16, wherein sorafenib dimethyl sulphoxide solvate
of Formula III is contacted with an acid of Formula HX at a temperature of about 15°C to
the reflux temperature of the solvent.
20. A pharmaceutical composition comprising sorafenib dimethyl sulphoxide solvate
of Formula III and one or more pharmaceutically acceptable carriers, diluents or
excipients.
21. Use of sorafenib dimethyl sulphoxide solvate of Formula III for the treatment of
cancer.
22. An HPLC method for the identification, quantification and isolation of related
substances of sorafenib or its pharmaceutically acceptable salts, comprising the use of a
buffer and a single organic solvent as mobile phase.
23. The HPLC method according to claim 22, wherein an acidic buffer is used.
24. The HPLC method according to claim 22, wherein the orthophosphoric acid in
water is used as buffer.
25. The HPLC method according to claim 22, wherein the organic solvent is selected
from the group consisting of alcohols, alkyl acetates and alkyl nitriles.
26. The HPLC method according to claim 25, wherein the alcohol is selected from
methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol, n-pentanol,
ethylene glycol or propylene glycol.
27. Sorafenib tosylate of Formula II substantially free of 4-(2-(N-methylcarbamonyl)-
4-(pyridyloxy) aniline.
28. Sorafenib tosylate of Formula II substantially free of 4-chloro-N-methyl-2-
pyridinecarboxamide.
29. Sorafenib tosylate of Formula II substantially free of 4-chloro-3-(trifluoromethyl)
phenyl isocyanate.