The present invention relates to novel crystal forms of Sunitinib, having the chemical name N-[2-(diethylamino)ethyl]-5-[(5-fluoro-1,2-dihydro-2-oxo-3H-indol-3-ylidene)methyl]-2,4-dimethyl-1H-pyrrole-3-carboxamide, and methods for their preparation.
Sunitinib, sold under the brand name Sutent® by Pfizer Pharma, is a receptor tyrosine kinase inhibitor which is used to treat disorders like renal cell carcinoma (RCC) and gastrointestinal stromal tumor (GIST). Its activity relies on the inhibition of cellular signaling by targeting multiple receptor tyrosine kinases including platelet-derived growth factor receptors and vascular endothelial growth factor receptors. Since both kinds of receptors are involved in tumor angiogenesis and tumor cell proliferation, the simultaneous inhibition of these targets results in both reduced tumor vascularization and cancer cell death. These effects are responsible for the finally observed shrinkage of the renal cell carcinoma and gastrointestinal stromal tumor, respectively.
Sunitinib and its pharmaceutical effects on disorders like cancer are described in EP 1255752. Further medical uses of Sunitinib and its salts are inter alia known from EP 1255536 and WO 03/035009.
EP 1255752 discloses Sunitinib and two processes for its preparation. According to these Sunitinib is obtained as a yellow green solid and as an orange solid, respectively. However, when repeating these processes, the yellow green solid cannot be obtained. According to the second process Sunitinib can be obtained.
The present invention relates to novel polymorphic forms of N-[2-(diethylamino)ethyl]-5-[(5-fluoro-1,2-dihydro-2-oxo-3H-indol-3-ylidene)methyl]-2,4-dimethyl-1H-pyrrole-3-carboxamide (Sunitinib) and processes for their preparation. Sunitinib has the following chemical structure:
Sunitinib can be obtained in a yellow to greenish yellow powder exhibiting a very low hygroscopicity. In the following, this crystal form of Sunitinib will be designated as “polymorphic form I” or “polymorph I”. This powder is fine particulate, hard to collect by filtration, highly electrostatic and tends to strongly stick to all kinds of surfaces.
Furthermore, the present invention provides a polymorphic form II of Sunitinib which does not exhibit the disadvantages of polymorphic form I but is slightly more hygroscopic.
Thirdly, the present invention provides a polymorphic form III of Sunitinib which is not hygroscopic and does not exhibit the disadvantages of polymorphic form I, thereby combining the advantages of polymorphs I and II.
Å Ångström
DSC differential scanning calorimetry
DMSG dynamic moisture sorption gravimetry
IR infrared
RH relative humidity
RT room temperature
SCXRD singe crystal X-ray diffraction
XRPD X-ray powder diffraction
The first embodiment of the present invention refers to the yellow to greenish yellow solid as described above, that will in the following be referred to as polymorph I of Sunitinib. It is characterized by an XRPD pattern having a characteristic peak at 4.5±0.2 degrees 2-theta, in particular with peaks at 4.5±0.2; 9.1±0.2; 16.8±0.2 and 26.0±0.2 degrees 2-theta.
Furthermore, polymorph I of Sunitinib can be characterized by an XRPD pattern with peaks at 4.5±0.2; 9.1±0.2; 15.2±0.2; 16.8±0.2; 18.3±0.2; 20.4±0.2; 21.8±0.2; 22.9±0.2 and 26.0±0.2 degrees 2-theta.
The XRPD pattern of polymorph I of Sunitinib is shown in
Polymorph I of Sunitinib shows a Raman spectrum exhibiting characteristic peaks at 2927±2 cm−1, 1679±2 cm−1, 1585±2 cm−1, 1437±2 cm−1, 1334±2 cm−1, 1278±2 cm−1 and 670±2 cm−1.
The Raman spectrum of polymorph I of Sunitinib is shown in
Polymorph I of Sunitinib shows an IR spectrum exhibiting characteristic peaks at 2969±2 cm−1, 1479±2 cm−1, 1330±2 cm−1, 1189±2 cm−1, 797±2 cm−1, 667±2 cm−1 and 609±2 cm−1.
The IR spectrum of polymorph I of Sunitinib is shown in
Polymorph I of Sunitinib exhibits a low hygroscopicity. DMSG revealed a moisture sorption of maximum about 1% referred to the weight of the sample.
Surprisingly, by crystallization and/or recrystallization of Sunitinib from different solvents and mixtures of two or more solvents further new polymorphic forms were found. While polymorph I of Sunitinib exhibits low hygroscopicity it has unfavourable properties such as an extremely fine particularity and bad filterability, stickiness to all sorts of surfaces and electrostatic properties hampering the industrial workability including the development of galenical formulations. In the handling of the further new polymorphs of Sunitinib the above mentioned problems in filterability, electrostatic properties and stickiness were not encountered.
The second embodiment of the present invention relates to polymorph II of Sunitinib. This crystal form has the following characteristics:
Polymorph II of Sunitinib is characterized by an XRPD pattern having a characteristic peak at 3.8±0.2 degrees of 2-theta, in particular with peaks at 3.8±0.2; 9.0±0.2; 14.0±0.2; 18.1±0.2 and 20.5±0.2 degrees 2-theta.
Furthermore, polymorph II of Sunitinib can be characterized by an XRPD pattern with peaks at 3.8±0.2; 9.0±0.2; 14.0±0.2; 18.1±0.2; 20.5±0.2; 26.6±0.5 and 27.5±0.6 degrees 2-theta.
The XRPD of polymorph II of Sunitinib is shown in
Polymorph II of Sunitinib shows a Raman spectrum exhibiting characteristic peaks at 2929±2 cm−1, 1627±2 cm−1, 1583±2 cm−1, 1425±2 cm−1, 1328±2 cm−1, 1285±2 cm−1, 1264±2 cm−1 and 669±2 cm−1.
The Raman spectrum of polymorph II of Sunitinib is shown in
Polymorph II of Sunitinib shows an IR spectrum exhibiting characteristic peaks at 1667±2 cm−1, 1476±2 cm−1, 1325±2 cm−1, 1147±2 cm−1, 794±2 cm−1, 668±2 cm−1 and 608±2 cm−1.
The IR spectrum of polymorph II of Sunitinib is shown in
Sunitinib in the polymorphic form II exhibits some hygroscopicity. DMSG revealed a moisture sorption of more than 6% referred to the weight of the sample.
The present invention relates to a process for the preparation of polymorph II of Sunitinib, comprising the steps of:
The crystallization is carried out in a suitable inert solvent or in a mixture of two or more suitable inert solvents. Examples of such suitable inert solvents are water, aliphatic and aromatic hydrocarbons (preferably hexane, benzene, toluene or xylene), aliphatic alcohols (preferably methanol, ethanol, propanol, iso-propanol), ethers (preferably diethyl ether, diisopropyl ether or dimethoxyethane), cyclic ethers (preferably tetrahydrofuran or dioxane), ketones (preferably acetone, methylisobutylketone or methylethylketone), esters (preferably ethylacetate), chlorinated hydrocharbons (preferably dichloromethane or chloroform) or nitrogen containing organic solvents (preferably N-methylpyrollidone, dimethylformamide or acetonitrile). Acetone, methylethylketone and toluene are especially preferred.
The present invention provides a further alternative process for the preparation of polymorph II of Sunitinib, comprising the steps of:
As solvents the suitable inert solvents as described above can be used.
The above described reaction is carried out in the presence of a base, preferably a Bronsted base. Examples of suitable Bronsted bases are metal hydroxides, metal carbonates or amines, preferably alkali metal hydroxides, alkali metal carbonates, alkali metal bicarbonates, ammonia, or organic amines, such as, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, ammonia, diethylamine, triethylamine, diisopropylamine or pyridine. Sodium hydroxide is preferred. The base is used in an amount sufficient to obtain the free base of Sunitinib from its salt.
The third embodiment of the present invention relates to polymorph III of Sunitinib. This crystal form has the following characteristics:
Polymorph III of Sunitinib is characterized by an XRPD pattern having a characteristic peak at 6.3±0.2 degrees 2-theta, in particular with peaks at 6.3±0.2; 22.2±0.2 and 26.4±0.2 degrees 2-theta.
Furthermore, polymorph III of Sunitinib can be characterized by an XRPD pattern with peaks at 6.3±0.2; 14.0±0.2; 15.4±0.2, 18.9±0.2, 19.3±0.2; 22.2±0.2; 24.2±0.2 and 26.4±0.2 degrees 2-theta.
The XRPD pattern of polymorph III of Sunitinib is shown in
Polymorph III of Sunitinib shows a Raman spectrum exhibiting characteristic peaks at 1674±2 cm−1, 1569±2 cm−1, 1414±2 cm−1, 1327±2 cm−1, 1297±2 cm−1, 1259±2 cm−1, 1030±2 cm−1 and 666±2 cm−1.
The Raman spectrum of polymorph III of Sunitinib is shown in
Polymorph III of Sunitinib shows an IR spectrum exhibiting characteristic peaks at 3435±2 cm−1, 1670±2 cm−1, 1473±2 cm−1, 1294±2 cm−1, 1194±2 cm−1, 1146±2 cm−1, 786±2 cm−1, 663±2 cm−1, 617±2 cm−1.
The IR spectrum of polymorph III of Sunitinib is shown in
Polymorph III exhibits a very low hygroscopicity. Under DMSG, the sample does not gain weight, even at a relative humidity of 95%.
Polymorph III is preferably further characterized by the absence of any solvent molecules within the crystal.
The present invention also relates to a process for the preparation of polymorph III of Sunitinib, comprising the steps of:
Preferably the process comprises the steps of:
The above described crystallizations are carried out in suitable inert solvents or mixtures of two or more suitable inert solvents. Examples of such suitable inert solvents are water, aliphatic and aromatic hydrocarbons (preferably hexane, benzene, toluene or xylene), aliphatic alcohols (preferably methanol, ethanol, propanol, iso-propanol), ethers (preferably diethyl ether, diisopropyl ether or dimethoxyethane), cyclic ethers (preferably tetrahydrofuran or dioxane), ketones (preferably acetone, methylisobutylketone or methylethylketone), esters (preferably ethylacetate), chlorinated hydrocharbons (preferably dichloromethane or chloroform) or nitrogen containing organic solvents (preferably N-methylpyrollidone, dimethylformamide or acetonitrile). Ketones, such as acetone and methylethylketone, as well as toluene are especially preferred.
In a preferred embodiment of the process for the preparation of polymorph III of Sunitinib of the present invention the seeding of the solution with crystals of polymorph III of Sunitinib is carried out at a temperature of the solution of about 40° C. to about 60° C., preferably of about 50° C. In this embodiment the preferred inert solvents are ketones, in particular methylethylketone.
The DSC thermogram in
The DSC thermogram in
Photographs of the 3 polymorphic forms of Sunitinib are shown in
DMSG data show that polymorph I is only slightly hygroscopic, which is a clear advantage over polymorph II, which is clearly hygroscopic. Polymorph III is not hygroscopic at all.
Polymorph I is only very slightly hygroscopic and polymorph II does not show the disadvantageous electrostatic properties of polymorph I. Thus, either of them possesses certain advantageous properties. For example, if used in pharmaceutical formulations for parenteral application, hygroscopicity is not a problem since these are prepared as liquids. Thus, polymorph II is advantageous over polymorph I for the preparation of parenteral dosage forms. On the other hand, electrostatic properties can be overcome by adding suitable excipients e.g. during a wet granulation process or the preparation of topical medicaments. Therefore polymorph I might be advantageous over polymorph II for the preparation of solid or semisolid dosage forms.
Polymorph III combines the advantages of the polymorphs I and II and therefore represents the preferred embodiment of the present invention.
The invention is further illustrated by the following examples which are not constructed as being limiting.
XRPD was performed on a STOE Transmission Diffractometer STADE P (2003-10) using the Kα1 band of a copper radiation source.
SCXRD was performed under the following measurement conditions:
Raman spectroscopy was performed on a Bruker IFS66 Raman Spectrometer (FRA 106).
DSC was performed on a DSC 204 Phoenix calorimeter (NETZSCH Gerätelabor GmbH) using closed aluminium crucibles under N2 atmosphere (0.45 bar) with a cooling/heating rate of 5° C./minute.
IR spectroscopy was performed on a Varian 3100 FT-IR-Spectrometer (Excalibur Series) using the ATR sampling technique.
DMSG was performed using an SPS11-100n instrument (Projekt Messtechnik) at a constant temperature of 25° C. and a change in RH of 5% per hour including isohumid conditions for 5 hours at 0% RH and for 2 hours at 50% RH.
Sunitinib was obtained according to example 35 (alternative synthesis) of EP 1255752 B1. 0.25 g of Sunitinib were mixed with 50 ml acetone and heated to reflux. Then, 5 ml toluene were added. The solvent was removed at 45° C. under reduced pressure of 250 to 300 mmHg until precipitation of the crystalline solid occurred. The product was collected by filtration, washed with 2 ml of cold toluene and dried for 24 hours at room temperature.
Sunitinib was obtained according to example 35 (alternative synthesis) of EP 1255752 B1. A suspension of Sunitinib was prepared in a mixture of acetone and toluene (1:1 v/v) at room temperature (RT). The suspension was heated to reflux for 1 hour, leading to a complete dissolution of Sunitinib. The solution was allowed to cool below boiling temperature and was then further cooled with a mixture of ice and sodium chloride as external cooling for 24 hours. The ice bath was not exchanged and the mixture was allowed to warm to RT. Further crystallization at RT for 48 hours resulted in a yellow precipitate, which was removed by filtration. The dark orange filtrate was kept at RT until dark orange needles were formed. These were isolated and dried for 24 hours at RT.
Sunitinib form II was refluxed in acetone to get a saturated solution. Undissolved solids were filtered off while hot and the clear solution was seeded with form III. The solvent was partially evaporated under vacuum using a water bath tempered at 30-40° C. and the residual solution was cooled to room temperature. The precipitate was filtered off, washed with acetone and dried under vacuum yielding Sunitinib free base as crystalline form III.
Sunitinib base form II was refluxed (80° C.) in methylethylketone to get a saturated solution (approximately 6.5 g of base and 20 ml of methylethylketone). Undissolved solids were filtered off while hot and the clear solution was seeded with form III (approximately 50° C.). The solvent was partially evaporated under vacuum using a water bath tempered at 30-40° C. and the residual solution was cooled to room temperature. The precipitate was filtered off, washed with methylethylketone and dried under vacuum yielding Sunitinib free base as crystalline form III.
Number | Date | Country | Kind |
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08.004143.7 | Mar 2008 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2009/001568 | 3/5/2009 | WO | 00 | 9/20/2010 |