WO2009133572A2 - Process for the preparation of amorphous raberazole sodium - Google Patents
Process for the preparation of amorphous raberazole sodium Download PDFInfo
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- WO2009133572A2 WO2009133572A2 PCT/IN2009/000252 IN2009000252W WO2009133572A2 WO 2009133572 A2 WO2009133572 A2 WO 2009133572A2 IN 2009000252 W IN2009000252 W IN 2009000252W WO 2009133572 A2 WO2009133572 A2 WO 2009133572A2
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- dielectric constant
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- rabeprazole
- ketonic
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D401/00—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom
- C07D401/02—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing two hetero rings
- C07D401/12—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing two hetero rings linked by a chain containing hetero atoms as chain links
Definitions
- the present invention relates to a novel process for the preparation of amorphous form of rabeprazole sodium.
- Rabeprazole sodium chemically known as ( ⁇ ) sodium-2-[[[4-(3-methoxypropoxy)-3-methyl- pyridinyl]methyl]sulfinyl]-lH-benzimidazole, is commercially available as Aciphex ® tablets, approved for healing of erosive or ulcerative gastroesophageal reflux disease, and maintenance of the healing, treatment of duodenal ulcers and treatment of symptomatic gastroesophageal reflux disease.
- United States Patent 5,045,552 which covers rabeprazole and its salts, exemplifies the preparation of rabeprazole sodium (example 33), wherein crude rabeprazole obtained by conventional process is dissolved in 0.1N aqueous sodium hydroxide to obtain a solution. This solution is distilled with ethanol thrice to remove the water as an azeotropic mixture with ethanol and dried in vacuum. Ether is added to the obtained residue to precipitate a white crystal, which is washed with ether and then dried to obtain rabeprazole sodium crystals.
- the patent also discloses preparation of amorphous rabeprazole sodium by freeze-drying a mixture of rabeprazole and aqueous sodium hydroxide.
- United States patent application 20060178406 claims a method of preparing amorphous rabeprazole sodium by heat drying a solvated crystal of the benzimidazole. Typically, the application discloses heat drying of an acetone or acetonitrile complex of the sodium ' salt of rabeprazole under reduced pressure.
- PCT application WO 2006024890 claims a process for preparation of amorphous rabeprazole sodium wherein the process involves dissolving rabeprazole in an alcoholic alkali solution at a temperature of 40-50 0 C for a period of 4-6 hours, charcolising the solution and filtering it, removal of the alcoholic solvent from the filtrate under vacuum at a temperature of 50-55 0 C to obtain a residue, dissolving the residue in an aliphatic halogenated hydrocarbon at a temperature of 20-25 0 C to obtain a solution, adding this solution to an alkane or ether solvent with stirring in an inert atmosphere to obtain a precipitate, separating the precipitate by filtering and drying under vacuum at a temperature ranging between 40-50 0 C for a time period of about 10 hours to 30 hours to obtain amorphous rabeprazole sodium.
- United States Patent application 20080071089 claims a process for the manufacture of amorphous rabeprazole sodium with mean particle diameter between 10 to 55 microns, said process comprising (a) addition of rabeprazole to an aqueous sodium hydroxide, (b) addition of ethyl alcohol to the solution, (c) distillation of solvents from the solution obtained till a thick mass is obtained, (d) addition of an organic solvent selected from C3 to C8 straight chain or branched aliphatic ester, chlorinated aliphatic hydrocarbon, cyclic ethers and mixtures thereof to the residue to obtain a clear solution, (e) addition of this clear solution to an anti-solvent under agitation, and (f) isolation of the product.
- PCT application WO 2008035192 claims a process for the preparation of amorphous rabeprazole sodium comprising (a) reacting rabeprazole with a solution of sodium tertiary butoxide in tertiary butyl alcohol, (b) removing tertiary butyl alcohol, after charcoal treatment and filtration, to give a residue, (c) adding diisopropyl ether, stirring, followed by separating amorphous rabeprazole sodium.
- Rabeprazole sodium is a hygroscopic compound, and in our experience extended, contact with protic solvents, incuding water, leads to degradation and/or discoloration of the product.
- One of the noticeable impacts is formation of the sulfone impurity (I).
- the process of the present invention uses water-immiscible organic solvents for preparation of amorphous rabeprazole sodium that are easy to remove and/or isolate, and to recover and reuse, thereby making the process highly commercially feasible.
- the process of the present invention avoids use of aqueous sodium hydroxide alone, unlike prior art. Use of aqueous sodium hydroxide alone, or use along with solvents like ethanol, involves tedious processes to remove the solvent contained in the product formed.
- the residual solvent content is difficult to remove or reduce, most often requiring prolonged drying times and/or use of processes such as freeze-drying.
- the residual water and/or solvent affects the quality of the product, since the product may discolor and/or the amount of the corresponding sulfone impurity may increase beyond acceptable limits.
- the organic solvents used in the process of the present invention are such that they can be analyzed for residual solvent content by conventional analytical methods
- the present invention provides a process for the preparation of amorphous rabeprazole sodium said process comprising
- step (d) adding ketonic solvent having dielectric constant ⁇ ranging, between 13_tp 21 to the residue of step (c) to obtain a solution;
- step (e) quenching the solution obtained in step (d) into an organic solvent having a dielectric constant ranging between 1.8 to 21, wherein at least 80% of the organic solvent is an ethereal solvent having dielectric constant ranging between 1.8 to 5.
- the present invention provides a process for the preparation of amorphous rabeprazole sodium, the said process comprising - (a) suspending rabeprazole in an organic solvent having dielectric constant ranging between 1.8 to 21, wherein at least 80% of the organic solvent is a ketonic solvent having dielectric constant ranging between 13 to 21,
- step (c) azeotropically distilling out water from the above reaction system to obtain a residue, (d) adding ketonic solvent having dielectric constant ranging between 13 to 21 to the residue of step (c) to obtain a solution, and
- step (e) quenching the solution obtained in step (d) into an organic solvent having a dielectric constant ranging between 1.8 to 21, wherein at least 80% of the organic solvent is an ethereal solvent having dielectric constant ranging between 1.8 to 5.
- the organic solvent having dielectric constant ranging between 1.8 to 21 may be selected from the group consisting of methyl isobutyl ketone , methyl ethyl ketone, acetone, methyl t-butyl ether , diisopropyl ether, diethyl ether, anisole.
- the ketonic solvent having dielectric constant ranging between 13 to 21, may be selected from the group consisting of methyl isobutyl ketone, methyl ethyl ketone, acetone.
- the ketonic solvents used in the process of the present invention do not form complex with the rabeprazole sodium formed.
- the organic solvent used in the process of the present invention is such that it is easily removed by conventional processes, without loss of time and effort.
- the ketonic solvent having dielectric constant ranging between 13 to 21 may be used singly or in combination with one or more solvents having dielectric constant ranging between 1.8 to 21 such that the ketonic solvent is present in atleast 80% in the total solvent mixture.
- the rabeprazole is suspended in a ketonic solvent having dielectric constant ranging between- L3_to .21...In one. preferred embodiment of the. present . invention, the ketonic solvent used in step (a) of the process is methyl isobutyl ketone.
- the ketonic solvent used in step (a) of the process is methyl isobutyl ketone.
- Use of methyl isobutyl ketone, along with the aqueous sodium hydroxide, is advantageous in that the water contained in the reaction system can be removed azeotropically, and the distillate can be "visually assesed" for the water content, owing to immiscibility of water with methyl isobutyl ketone, thereby ensuring near complete removal of the water from the reaction system.
- Methyl isobutyl ketone offers the additional advantage of having the ability to solubilise the rabeprazole sodium formed. Thus, if need be, the solution can be charcoalised to improve the color
- the aqueous sodium hydroxide is added to the suspension of crude rabeprazole in organic solvent having dielectric constant ranging between 1.8 to 21. This addition is carried out under stirring over a period of about ten minutes at ambient temperature, followed by further stirring until a biphasic reaction system is obtained. The water contained in the reaction system is then azeotropically distilled out to obtain a residual syrupy mass.
- a ketonic solvent having dielectric constant ranging between 13 to 21 may then be added to this syrupy mass, and the solution may be distilled to remove the solvent completely to obtain a residual mass.
- the residual mass is again dissolved in a ketonic solvent having dielectric constant ranging between 13 to 21 to obtain a clear solution.
- the ketonic solvent is methyl isobutyl ketone
- the solution of residual mass is quenched by adding dropwise with stirring to a mixture containing an organic solvent having dielectric constant ranging between 1.8 to 21, wherein at least 80% of the solvent is an ethereal solvent having dielectric constant ranging between 1.8 to 5.
- organic solvents having dielectric constant ranging between 1.8 to 5 include, but are not limited to, ethers, aliphatic hydrocarbons, aromatic hydrocarbons and mixtures thereof, wherein at least 80% of the solvent is an ethereal solvent having dielectric constant ranging between 1.8 to 5.
- the ethereal solvent having dielectric constant ranging between 1.8 to 5 may be selected from the group consisting of methyl t-butyl ether, diisopropyl ether, diethyl ether, anisole
- a preferred solvent with dielectric constant ranging between 1.8 to 5 is methyl t-butyl ether.
- an ethereal solvent having dielectric constant ranging between 1.8 to. 5 may be used singly or in combination with one or more solvents having dielectric constant ranging between 1.8 to 21 such that the ethereal solvent is present in atleast 80% in the total solvent mixture.
- the solution of the residual mass in methyl isobutyl ketone is added with stirring to a mixture of methyl isobutyl ketone and methyl t-butyl ether.
- the reaction system is stirred for about 2 hours at room temperature, and then optionally cooled to 0- 5 0 C, to obtain the amorphous rabeprazole sodium.
- the product is filtered under nitrogen atmosphere and dried under vacuum.
- the amorphous rabeprazole sodium obtained by the process of the present invention has the corresponding sulfone impurity less than 0.5%.
- the amorphous rabeprazole sodium obtained has sulfone impurity less than 0.3%, more preferably less than 0.15%.
- the present invention provides a process for the preparation of amorphous rabeprazole sodium having the corresponding sulfone impurity in less than 0.5% said process comprising
- step (d) adding ketonic solvent having dielectric constant ranging between 13 to 21 to the residue of step (c) to obtain a solution;
- step (e) quenching the solution obtained in step (d) into a mixture of ketonic solvent having dielectric constant ranging between 13 to 21 and ethereal solvent having dielectric constant ranging between 1.8 to 5
- the ketonic solvent having dielectric constant ranging between 13 to 21, may be selected from the group consisting of methyl isobutyl ketone, methyl ethyl ketone, acetone.ln one embodiment methyl isobutyl ketone is added to the residue obtained after azeotropic distillation to obtain a solution of the residual mass in methyl isobutyl ketone. This solution is then quenched by adding with stirring-to a mixture of ketonic solvent.having-dielectric constant ranging between 13 to 21 and ethereal solvent having dielectric constant ranging between 1.8 to 5. Preferably at least 80% of the solvent mixture is an ethereal solvent having dielectric constant ranging between 1.8 to 5.
- the solution is quenched in methyl isobutyl ketone and methyl t-butyl ether.
- the methyl t-butyl ether is present in the mixture to the extent of atleast 80%.
- the reaction system is stirred for about 2 hours at room temperature, and then optionally cooled to 0-5 0 C, to obtain the amorphous rabeprazole sodium.
- Example 1 25g of crude rabeprazole is added to 125ml of methyl isobutyl ketone and stirred to obtain a homogenous suspension. Aqueous sodium hydroxide is then added to this suspension with stirring over a period of about 10 minutes. The reaction mixture is stirred at room temperature for another 15-30 minutes until a biphasic reaction mixture is obtained. This reaction mixture is then distilled at 45-50 0 C under vacuum to remove the solvents. The syrupy mass thus obtained is mixed with 50ml of methyl isobutyl ketone, distilled under vacuum at 45-50 0 C and degassed for 30 minutes to obtain a residual mass. This residual mass is dissolved in 50ml of methyl isobutyl ketone to obtain a clear solution.
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Abstract
The present invention provides a process for the preparation of amorphous rabeprazole sodium said process comprising (a) suspending rabeprazole in an organic solvent having dielectric constant ranging between 1.8 to 21, wherein at least 80 % of the organic solvent is a ketonic solvent having dielectric constant ranging between 13 to 21; (b) adding aqueous sodium hydroxide; (c) azeotropically distilling out water from the above reaction system to obtain a residue, (d) adding ketonic solvent having dielectric constant ranging between 13 to 21 to the residue of step (c) to obtain a solution; and (e) quenching the solution obtained in step (d) into an organic solvent having a dielectric constant ranging between 1.8 to 21, wherein at least 80 % of the organic solvent is an ethereal solvent having dielectric constant ranging between 1.8 to 5.
Description
PROCESS FOR THE PREPARATION OF AMORPHOUS RABEPRAZOLE SODIUM FIELD OF INVENTION
The present invention relates to a novel process for the preparation of amorphous form of rabeprazole sodium.
Rabeprazole sodium, chemically known as (±) sodium-2-[[[4-(3-methoxypropoxy)-3-methyl- pyridinyl]methyl]sulfinyl]-lH-benzimidazole, is commercially available as Aciphex® tablets, approved for healing of erosive or ulcerative gastroesophageal reflux disease, and maintenance of the healing, treatment of duodenal ulcers and treatment of symptomatic gastroesophageal reflux disease.
BACKGROUND OF INVENTION
United States Patent 5,045,552, which covers rabeprazole and its salts, exemplifies the preparation of rabeprazole sodium (example 33), wherein crude rabeprazole obtained by conventional process is dissolved in 0.1N aqueous sodium hydroxide to obtain a solution. This solution is distilled with ethanol thrice to remove the water as an azeotropic mixture with ethanol and dried in vacuum. Ether is added to the obtained residue to precipitate a white crystal, which is washed with ether and then dried to obtain rabeprazole sodium crystals. The patent also discloses preparation of amorphous rabeprazole sodium by freeze-drying a mixture of rabeprazole and aqueous sodium hydroxide.
United States patent application 20060178406 claims a method of preparing amorphous rabeprazole sodium by heat drying a solvated crystal of the benzimidazole. Typically, the application discloses heat drying of an acetone or acetonitrile complex of the sodium ' salt of rabeprazole under reduced pressure.
PCT application WO 2006024890 claims a process for preparation of amorphous rabeprazole sodium wherein the process involves dissolving rabeprazole in an alcoholic alkali solution at a temperature of 40-500C for a period of 4-6 hours, charcolising the solution and filtering it, removal of the alcoholic solvent from the filtrate under vacuum at a temperature of 50-550C to obtain a residue, dissolving the residue in an aliphatic halogenated hydrocarbon at a temperature of 20-250C to obtain a solution, adding this solution to an alkane or ether solvent with stirring in an inert atmosphere to obtain a precipitate, separating the precipitate by filtering and drying under vacuum at a temperature ranging between 40-500C for a time period of about 10 hours to 30
hours to obtain amorphous rabeprazole sodium.
United States Patent application 20080071089 claims a process for the manufacture of amorphous rabeprazole sodium with mean particle diameter between 10 to 55 microns, said process comprising (a) addition of rabeprazole to an aqueous sodium hydroxide, (b) addition of ethyl alcohol to the solution, (c) distillation of solvents from the solution obtained till a thick mass is obtained, (d) addition of an organic solvent selected from C3 to C8 straight chain or branched aliphatic ester, chlorinated aliphatic hydrocarbon, cyclic ethers and mixtures thereof to the residue to obtain a clear solution, (e) addition of this clear solution to an anti-solvent under agitation, and (f) isolation of the product.
PCT application WO 2008035192 claims a process for the preparation of amorphous rabeprazole sodium comprising (a) reacting rabeprazole with a solution of sodium tertiary butoxide in tertiary butyl alcohol, (b) removing tertiary butyl alcohol, after charcoal treatment and filtration, to give a residue, (c) adding diisopropyl ether, stirring, followed by separating amorphous rabeprazole sodium.
Rabeprazole sodium is a hygroscopic compound, and in our experience extended, contact with protic solvents, incuding water, leads to degradation and/or discoloration of the product. One of the noticeable impacts is formation of the sulfone impurity (I).
(I)
Hence, in order to obtain rabeprazole sodium with low levels of impurity, it is important to ensure that the process involves minimal use of protic solvents, and the final product has low residual content of the protic solvent(s), if any.
We have now found a novel process for the preparation of amorphous rabeprazole sodium that is an industrially and commercially feasible process, and which process provides a product with low impurity. The process of the present invention uses water-immiscible organic solvents for
preparation of amorphous rabeprazole sodium that are easy to remove and/or isolate, and to recover and reuse, thereby making the process highly commercially feasible.The process of the present invention avoids use of aqueous sodium hydroxide alone, unlike prior art. Use of aqueous sodium hydroxide alone, or use along with solvents like ethanol, involves tedious processes to remove the solvent contained in the product formed. The residual solvent content is difficult to remove or reduce, most often requiring prolonged drying times and/or use of processes such as freeze-drying. As mentioned above, the residual water and/or solvent affects the quality of the product, since the product may discolor and/or the amount of the corresponding sulfone impurity may increase beyond acceptable limits. Also, the organic solvents used in the process of the present invention are such that they can be analyzed for residual solvent content by conventional analytical methods
SUMMARY OF THE INVENTION
The present invention provides a process for the preparation of amorphous rabeprazole sodium said process comprising
(a) ' suspending rabeprazole in an organic solvent having dielectric constant ranging between 1.8 to 21, wherein at least 80% of the organic solvent is a ketonic solvent having dielectric constant ranging between 13 to 21 ;
(b) adding aqueous sodium hydroxide; (c) azeotropically distilling out water from the above reaction system to obtain a residue,
(d) adding ketonic solvent having dielectric constant^ ranging, between 13_tp 21 to the residue of step (c) to obtain a solution; and
(e) quenching the solution obtained in step (d) into an organic solvent having a dielectric constant ranging between 1.8 to 21, wherein at least 80% of the organic solvent is an ethereal solvent having dielectric constant ranging between 1.8 to 5.
DETAILED DESCRIPTION OF THE INVENTION
Accordingly, the present invention provides a process for the preparation of amorphous rabeprazole sodium, the said process comprising - (a) suspending rabeprazole in an organic solvent having dielectric constant ranging between 1.8 to 21, wherein at least 80% of the organic solvent is a ketonic solvent having dielectric constant ranging between 13 to 21,
(b) adding aqueous sodium hydroxide,
(c) azeotropically distilling out water from the above reaction system to obtain a residue,
(d) adding ketonic solvent having dielectric constant ranging between 13 to 21 to the residue of step (c) to obtain a solution, and
(e) quenching the solution obtained in step (d) into an organic solvent having a dielectric constant ranging between 1.8 to 21, wherein at least 80% of the organic solvent is an ethereal solvent having dielectric constant ranging between 1.8 to 5.
The organic solvent having dielectric constant ranging between 1.8 to 21 may be selected from the group consisting of methyl isobutyl ketone , methyl ethyl ketone, acetone, methyl t-butyl ether , diisopropyl ether, diethyl ether, anisole.
The ketonic solvent having dielectric constant ranging between 13 to 21, may be selected from the group consisting of methyl isobutyl ketone, methyl ethyl ketone, acetone. The ketonic solvents used in the process of the present invention do not form complex with the rabeprazole sodium formed. Also, the organic solvent used in the process of the present invention is such that it is easily removed by conventional processes, without loss of time and effort. For suspending rabeprazole the ketonic solvent having dielectric constant ranging between 13 to 21 may be used singly or in combination with one or more solvents having dielectric constant ranging between 1.8 to 21 such that the ketonic solvent is present in atleast 80% in the total solvent mixture.
In one embodiment the rabeprazole is suspended in a ketonic solvent having dielectric constant ranging between- L3_to .21...In one. preferred embodiment of the. present . invention, the ketonic solvent used in step (a) of the process is methyl isobutyl ketone. Use of methyl isobutyl ketone, along with the aqueous sodium hydroxide, is advantageous in that the water contained in the reaction system can be removed azeotropically, and the distillate can be "visually assesed" for the water content, owing to immiscibility of water with methyl isobutyl ketone, thereby ensuring near complete removal of the water from the reaction system. Methyl isobutyl ketone offers the additional advantage of having the ability to solubilise the rabeprazole sodium formed. Thus, if need be, the solution can be charcoalised to improve the color.
The aqueous sodium hydroxide is added to the suspension of crude rabeprazole in organic solvent having dielectric constant ranging between 1.8 to 21. This addition is carried out under stirring over a period of about ten minutes at ambient temperature, followed by further stirring until a biphasic reaction system is obtained.
The water contained in the reaction system is then azeotropically distilled out to obtain a residual syrupy mass.
A ketonic solvent having dielectric constant ranging between 13 to 21 may then be added to this syrupy mass, and the solution may be distilled to remove the solvent completely to obtain a residual mass. The residual mass is again dissolved in a ketonic solvent having dielectric constant ranging between 13 to 21 to obtain a clear solution. Preferrably the ketonic solvent is methyl isobutyl ketone
The solution of residual mass is quenched by adding dropwise with stirring to a mixture containing an organic solvent having dielectric constant ranging between 1.8 to 21, wherein at least 80% of the solvent is an ethereal solvent having dielectric constant ranging between 1.8 to 5. Examples of such organic solvents having dielectric constant ranging between 1.8 to 5 include, but are not limited to, ethers, aliphatic hydrocarbons, aromatic hydrocarbons and mixtures thereof, wherein at least 80% of the solvent is an ethereal solvent having dielectric constant ranging between 1.8 to 5. The ethereal solvent having dielectric constant ranging between 1.8 to 5 may be selected from the group consisting of methyl t-butyl ether, diisopropyl ether, diethyl ether, anisole
A preferred solvent with dielectric constant ranging between 1.8 to 5 is methyl t-butyl ether.
For quenching the solution, an ethereal solvent having dielectric constant ranging between 1.8 to. 5 may be used singly or in combination with one or more solvents having dielectric constant ranging between 1.8 to 21 such that the ethereal solvent is present in atleast 80% in the total solvent mixture.
In one embodiment of the present invention the solution of the residual mass in methyl isobutyl ketone is added with stirring to a mixture of methyl isobutyl ketone and methyl t-butyl ether. The reaction system is stirred for about 2 hours at room temperature, and then optionally cooled to 0- 50C, to obtain the amorphous rabeprazole sodium. The product is filtered under nitrogen atmosphere and dried under vacuum.
The amorphous rabeprazole sodium obtained by the process of the present invention has the corresponding sulfone impurity less than 0.5%. In preferred embodiments of the process of the
present invention, the amorphous rabeprazole sodium obtained has sulfone impurity less than 0.3%, more preferably less than 0.15%.
In one embodiment the present invention provides a process for the preparation of amorphous rabeprazole sodium having the corresponding sulfone impurity in less than 0.5% said process comprising
(a) suspending rabeprazole in a ketonic solvent having dielectric constant ranging between 13 to 21;
(b) adding aqueous sodium hydroxide; (c) azeotropically distilling out water from the above reaction system to obtain a residue,
(d) adding ketonic solvent having dielectric constant ranging between 13 to 21 to the residue of step (c) to obtain a solution; and
(e) quenching the solution obtained in step (d) into a mixture of ketonic solvent having dielectric constant ranging between 13 to 21 and ethereal solvent having dielectric constant ranging between 1.8 to 5
The ketonic solvent having dielectric constant ranging between 13 to 21, may be selected from the group consisting of methyl isobutyl ketone, methyl ethyl ketone, acetone.ln one embodiment methyl isobutyl ketone is added to the residue obtained after azeotropic distillation to obtain a solution of the residual mass in methyl isobutyl ketone. This solution is then quenched by adding with stirring-to a mixture of ketonic solvent.having-dielectric constant ranging between 13 to 21 and ethereal solvent having dielectric constant ranging between 1.8 to 5. Preferably at least 80% of the solvent mixture is an ethereal solvent having dielectric constant ranging between 1.8 to 5.
In one embodiment the solution is quenched in methyl isobutyl ketone and methyl t-butyl ether. The methyl t-butyl ether is present in the mixture to the extent of atleast 80%. The reaction system is stirred for about 2 hours at room temperature, and then optionally cooled to 0-50C, to obtain the amorphous rabeprazole sodium.
The examples that follow do not limit the scope of the present invention and are merely added as illustrations.
Example 1 25g of crude rabeprazole is added to 125ml of methyl isobutyl ketone and stirred to obtain a homogenous suspension. Aqueous sodium hydroxide is then added to this suspension with stirring over a period of about 10 minutes. The reaction mixture is stirred at room temperature for another 15-30 minutes until a biphasic reaction mixture is obtained. This reaction mixture is then distilled at 45-500C under vacuum to remove the solvents. The syrupy mass thus obtained is mixed with 50ml of methyl isobutyl ketone, distilled under vacuum at 45-500C and degassed for 30 minutes to obtain a residual mass. This residual mass is dissolved in 50ml of methyl isobutyl ketone to obtain a clear solution. This clear solution is added dropwise, with stirring, to a mixture containing 375ml of methyl t-butyl ether and 12.5ml of methyl isobutyl ketone. The mixture is stirred for about 1 to 2 hours at room temperature, followed by cooling to 0-50C for about 1 to 2 hours. The product obtained is filtered under nitrogen atmosphere and dried under vacuum at 45- 500C for about 10 hours. The amorphous rabeprazole sodium thus obtained contains 0.05% of the corresponding sulfone impurity, when analyzed by HPLC.
Claims
1. A process for the preparation of amorphous rabeprazole sodium said process comprising
(a) suspending rabeprazole in an organic solvent having dielectric constant ranging between 1.8 to 21, wherein at least 80% of the organic solvent is a ketonic solvent having dielectric constant ranging between 13 to 21 ;
(b) adding aqueous sodium hydroxide;
(c) azeotropically distilling out water from the above reaction system to obtain a residue,
(d) adding ketonic solvent having dielectric constant ranging between 13 to 21 to the residue of step (c) to obtain a solution; and (e) quenching the solution obtained in step (d) into an organic solvent having a dielectric constant ranging between 1.8 to 21, wherein at least 80% of the organic solvent is an ethereal solvent having dielectric constant ranging between 1.8 to 5.
2. A process as claimed in claim 1 wherein the organic solvent having dielectric constant ranging between 1.8 to 21 is selected from methyl isobutyl ketone , methyl ethyl ketone, acetone, methyl t-butyl ether , diisopropyl ether, diethyl ether, anisole, or mixtures thereof.
3. A process as claimed in claim 1 wherein the ketonic solvent having dielectric constant ranging between 13_to 21 is selected form the group consisting of methyl isobutyl ketone , methyl ethyl ketone, acetone.
4. A process as claimed in claim 1 wherein the ethereal solvent having dielectric constant ranging between 1.8 to 5 is selected form the group consisting of methyl t-butyl ether , diisopropyl ether, diethyl ether, anisole.
5. A process for the preparation of amorphous rabeprazole sodium said process comprising
(a) suspending rabeprazole in a ketonic solvent having dielectric constant ranging between 13 to 21;
(b) adding aqueous sodium hydroxide;
(c) azeotropically distilling out water from the above reaction system to obtain a residue,
(d) adding ketonic solvent having dielectric constant ranging between 13 to 21 to the residue of step (c) to obtain a solution; and (e) quenching the solution obtained in step (d) into a mixture of ketonic solvent having dielectric constant ranging between 13 to 21 and ethereal solvent having dielectric constant ranging between 1.8 to 5.
6. A process as claimed in claim 5 wherein in step (d) at least 80% of the solvent mixture is an ethereal solvent having dielectric constant ranging between 1.8 to 5.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IN932MU2008 | 2008-04-28 | ||
| IN932/MUM/2008 | 2008-04-28 |
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| WO2009133572A2 true WO2009133572A2 (en) | 2009-11-05 |
| WO2009133572A3 WO2009133572A3 (en) | 2010-12-23 |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006024890A1 (en) * | 2004-08-30 | 2006-03-09 | Apollo International Limited | Improved process for rabeprazole sodium in amorphous form |
| WO2007023393A2 (en) * | 2005-08-02 | 2007-03-01 | Medichem, S.A. | Novel processes for the production of amorphous rabeprazole sodium |
| WO2008155780A2 (en) * | 2007-06-21 | 2008-12-24 | Matrix Laboratories Ltd | Improved process for the preparation of pure rabeprazole |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006024890A1 (en) * | 2004-08-30 | 2006-03-09 | Apollo International Limited | Improved process for rabeprazole sodium in amorphous form |
| WO2007023393A2 (en) * | 2005-08-02 | 2007-03-01 | Medichem, S.A. | Novel processes for the production of amorphous rabeprazole sodium |
| WO2008155780A2 (en) * | 2007-06-21 | 2008-12-24 | Matrix Laboratories Ltd | Improved process for the preparation of pure rabeprazole |
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| WO2009133572A3 (en) | 2010-12-23 |
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