Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D471/00—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, at least one ring being a six-membered ring with one nitrogen atom, not provided for by groups C07D451/00 - C07D463/00
  • C07D471/02—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, at least one ring being a six-membered ring with one nitrogen atom, not provided for by groups C07D451/00 - C07D463/00 in which the condensed system contains two hetero rings
  • C07D471/04—Ortho-condensed systems
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P25/00—Drugs for disorders of the nervous system
  • A61P25/18—Antipsychotics, i.e. neuroleptics; Drugs for mania or schizophrenia

Definitions

• the present invention relates to a process for the purification of Paliperidone from its impurities. Also, the present invention relates to pure paliperidone.
• Paliperidone is a metabolite of Risperidone. Marketed under the name, Invega , Paliperidone is a psychotropic agent approved in the United States for the treatment of schizophrenia. Processes for the synthesis of Paliperidone, are described in U.S. Patent No. 5,158,952. Another process for the synthesis of a precursor of Paliperidone, (3-(2- chIoroethyl)-2-methyl-9-benzyloxy-4H-pyrido[l,2-a]- pyrimidine-4-one), is described in the above publications.
• paliperidone can contain extraneous compounds or impurities that can come from many sources. They can be unreacted starting materials, by-products of the reaction, products of side reactions, or degradation products. Impurities in paliperidone or any active pharmaceutical ingredient (API) are undesirable and, in extreme cases, might even be harmful to a patient being treated with a dosage form containing the API.
• API active pharmaceutical ingredient
• impurities in an API may arise from degradation of the API itself, which is related to the stability of the pure API during storage, and the manufacturing process, including the chemical synthesis.
• Process impurities include unreacted starting materials, chemical derivatives of impurities contained in starting materials, synthetic by-products, and degradation products.
• the product mixture of a chemical reaction is rarely a single compound with sufficient purity to comply with pharmaceutical standards. Side products and byproducts of the reaction and adjunct reagents used in the reaction will, in most cases, also be present in the product mixture.
• it At certain stages during processing of the API, paliperidone, it must be analyzed for purity, typically, by HPLC, TLC or GC analysis, to determine if it is suitable for continued processing and, ultimately, for use in a pharmaceutical product.
• the API need not be absolutely pure, as absolute purity is a theoretical ideal that is typically unattainable. Rather, purity standards are set with the intention of ensuring that an API is as free of impurities as possible, and, thus, are as safe as possible for clinical use. As discussed above, in the United States, the Food and Drug Administration guidelines recommend that the amounts of some impurities be limited to less than 0.1 percent.
• impurities side products, by-products, and adjunct reagents (collectively “impurities”) are identified spectroscopically and/or with another physical method, and then associated with a peak position, such as that in a chromatogram, or a spot on a TLC plate.
• a peak position such as that in a chromatogram, or a spot on a TLC plate.
• the impurity can be identified, e.g., by its relative position in the chromatogram, where the position in a chromatogram is conventionally measured in minutes between injection of the sample on the column and elution of the particular component through the detector.
• the relative position in the chromatogram is known as the "retention time.”
• the retention time can vary about a mean value based upon the condition of the instrumentation, as well as many other factors.
• practitioners use the "relative retention time" ("RRT") to identify impurities. (Strobel p. 922).
• RRT relative retention time
• the RRT of an impurity is its retention time divided by the retention time of a reference marker. It may be advantageous to select a compound other than the API that is added to, or present in, the mixture in an amount sufficiently large to be detectable and sufficiently low as not to saturate the column, and to use that compound as the reference marker for determination of the RRT.
• the commercial tablet Invega ® appears to contain 0.10% of PLP- NO.
• the present invention provides paliperidone containing less than about 0.2% of the impurity PLP-NO.
• the paliperidone of the present invention contains less than about 0.1%, more preferably less than 0.05% and most preferably less than 0.02% of the impurity PLP-NO.
• the present invention provides paliperidone having a total purity of at least about 98%.
• the total purity is at least about 99%, most preferably at least about 99.9%.
• the present invention provides processes for purifying paliperidone.
• CHTP 3-(2-chloroethyl)-6,7,8,9- tetrahydro-9-hydroxy-2-methyl-4H-pyrrido[l,2-a]- pyrimidin-4-one of the following structure:
• FBIP 6-fluoro-3-piperidino-l,2- benisoxazole of the following structure:
• PRP-NO refers to 3-[2-[4-(6- fluorobenzo[d]isoxazol-3-yl)-l-oxypiperid ⁇ n-l-yl]ethyl]-7-hydroxy-4-methyl-l,5- diazabicyclo[4.4.0]deca-3,5-dien-2-one of the following structure:
• PGP-car refers to 2-[4-(6-fluoro-l ,2-benzisoxazol- 3-yl)piperidin-l-carboxylicacid]-7-hydroxy-2-methyl-6,7,8,9-tetrahydro-4H- pyrido[l,2-a]pyrimidin-4-one-3-yl-ethyl ester of the following structure:
• reduced pressure refers to a pressure of under 100 mm Hg.
• the present invention provides pure paliperidone, as well as processes for preparing thereof.
• pure paliperidone refers to paliperidone containing less than about 0.2% of the impurity PLP-NO.
• the paliperidone of the present invention contains less than about 0.1%, more preferably less than 0.05% and most preferably less than 0.02% of the impurity PLP-NO.
• the pure paliperido ⁇ e of the present invention contains PLP-NO at less than about 0.2%, preferably less than about 0.1%, more preferably less than 0.05% and most preferably less than 0.02%.
• the purity is preferably measured by HPLC, and is presented as % area as shown in the HPLC chromatogram.
• the pure paliperidone of the present invention has a total purity of at least about 98%.
• the total purity is at least about 99%, most preferably at least about 99.9%.
• the total purity of the pure paliperidone of the present invention can be about 98% to about 99.95%, about 98% to about 99.99%, about 99% to about 99.95%, or about 99% to about 99.99%.
• the purity is preferably measured as described above.
• the present invention further provides a process for the purification of paliperidone.
• This process comprises crystallizing paliperidone from a solvent selected from the group consisting of: C3-6 ketone or a mixture thereof with water, N- methylpyrrolidone, C 3-6 amides, halo-substituted Cg -I2 aromatic hydrocarbons propylene glycole, dimethyl sulfoxide, di-methyl carbonate, CM alkyl alcohols, a mixture of a Ci-s alkyl alcohol and water, acetonitrile or a mixture thereof with water, C 2 - 6 alkyl acetates or their mixture with water, cellosolve, dimethyl carbonate, polyethylene glycol methyl ether and C2-8 ethers.
• a solvent selected from the group consisting of: C3-6 ketone or a mixture thereof with water, N- methylpyrrolidone, C 3-6 amides, halo-substituted Cg -I2 aromatic
• the crystallization is preferably performed by dissolving paliperidone in the above solvent, preferably by heating the reaction mixture to allow complete dissolution, followed by cooling of the obtained solution, whereby paliperidone crystallizes.
• Preferred C 3- ⁇ ketones are acetone, methyl ethyl ketone (MEK) and methyl iso-butyl ketone (MIBK).
• Preferred C3_ 6 amides are dimethylacetamide and dimethylformamide.
• Preferred halo-substituted Ce-i2 aromatic hydrocarbons are chlorobenzene and dichlorobenzene.
• Preferred C M alkyl alcohols are methanol, ethanol, n-propanpl, isopropanol, n-butanol, isobutanol and 2-butanol.
• Preferred C 2 - 6 alkyl acetates are ethyl acetate and isobutyl acetate.
• Preferred C 2-S ethers are dibutyl ether and polyethylene glycol (PGME).
• the solvent is a mixture of acetone and water. When a mixture is used (such as acetone: water, ethanol:water etc.), the ratio between the solvents is between about 1 :1 to about 3:1 by volume. The ratio of acetone to water is preferably about 3:1 by volume.
• the obtained product is preferably recovered by filtering, washing of the obtained crystals, and drying, preferably overnight under reduced pressure.
• Paliperidone obtained by the above process preferably contains PLP-NO and PLP-car, each one in an amount of less than about 0.2%.
• the above crystallization process may be repeated in order to further purify the obtained paliperidone, so that the PLP-NO and PLP-car levels may be reduced to less than about 0.02%.
• the total purity of the paliperidone obtained by the above processes is of at least about 98%, more preferably, at least about 99% and most preferably at least about 99.9%.
• the purity is measured as described above.
• the present invention provides a process for the purification of paliperidone comprising crystallizing paliperidone by combining a solution of paliperidone in a first solvent with an anti-solvent.
• the solution is obtained by dissolving paliperidone in dichloromethane, preferably at a reflux temperature.
• the obtained solution is then cooled, preferably to a temperature of about 0 0 C to about 30 0 C, preferably to a temperature of about 20 0 C to about 30 0 C, and most preferably of about 25°C, followed by admixing with the anti-solvent described above.
• the admixing may be done in any order, for example, the anti-solvent may be added to the solution, or alternatively, the solution may be added to the anti-solvent.
• the temperature difference causes the fast crystallization.
• the addition may be added dropwise or in one volume.
• the first solvent is selected from the group consisting of: dichloromethane, dioxane and Ci_ 4 alkyl alcohols. Most preferably the first solvent is selected from the group consisting of: dichloromethane, dioxane, butanol and n-propanol.
• the anti-solvent is selected from the group consisting Of C 3-6 ketones, C 3 - 6 ethers, acetonitrile, C 3 . 7 straight and cyclic carbohydrates, C6-12 aromatic carbohydrates and water. More preferably, the anti-solvent is selected from the group consisting of: methyl t-butyl ether (MTBE), MEK, acetone, MIBK, acetonitrile, cyclohexane, hexane, heptane, toluene, benzene, xylene and water.
• MTBE methyl t-butyl ether
• MEK methyl t-butyl ether
• MIBK MIBK
• the anti solvent is selected from the group consisting of MTBE, MEK, acetonitrile, cyclohexane, heptane, toluene and water.
• the anti-solvent is selected from the group consisting of acetonitrile, MEK, toluene and MTBE.
• Paliperido ⁇ e obtained by the above process preferably contains PLP-NO in an amount of less than about 0.2% and PLP-car in an mount of less than about 0.04%.
• the above crystallization process may be repeated in order to further purify the obtained paliperidone, so that the PLP-NO and PLP-car levels may be reduced to less than about 0.02%.
• the total purity of the paliperidone obtained by the above processes is of at least about 98%, more preferably, at least about 99% and most preferably at least about 99.9%.
• the purity is measured as described above.
• the present invention provides a process for the purification of paliperidone comprising slurrying paliperidone in an organic solvent.
• the slurrying is performed at a temperature of about 2O 0 C to about 7O 0 C, more preferably at a temperature of about 25°C to about 65°C.
• the slurrying is performed for a period of time sufficient for purifying paliperidone, more preferably from about 30 minutes to about 24 hours.
• the organic solvent is selected from Ci -4 alkyl alcohols, C 3 .5 ketones and water.
• the organic solvent is selected from ethanol, methanol, isopropanol, acetone and water.
• the obtained product is preferably recovered by filtering.
• Paliperidone obtained by the above process preferably contains PLP-NO in an amount of less than about 0.3%, and PLP-Car in an amount of less than about 0.04%.
• the above slurrying process may be repeated in order to further purify the obtained paliperidone, so that the PLP-NO and PLP-car levels may be reduced to less than about 0.02%.
• the total purity of the paliperidone obtained by the above processes is of at least about 98%, more preferably, at least about 99% and most preferably at least about 99.9%.
• the purity is measured as described above.
• the present invention further provides a process for the purification of paliperidone comprising providing a paliperidone solution containing more than about 0.1 % PLP-NO or more than about 2% of any other impurity; admixing the solution with finely powdered carbon; and filtrating the admixture to obtain pure paliperidone.
• the filtering step is performed in order to remove the finely powdered carbon.
• the solution is obtained by dissolving paliperidone in an organic solvent.
• the organic solvent is preferably a mixture of acetone: water.
• finely powdered carbon is an active carbon.
• the active carbon is preferably selected from the group consisting of HB ultra, CGP super, GBG, SX plus, ROX 0.8 and A super eur.
• the filtration is preferably done through hi-fiow.
• Paliperidone obtained by the above process preferably contains PLP-NO in an amount of less than about 0.12% and PLP-car in an amount of less than about 0.05%.
• the above crystallization process may be repeated in order to further purify the obtained paliperidone, so that the PLP-NO and PLP-car levels may be reduced to less than about 0.02%.
• the total purity of the paliperidone obtained by the above processes is of at least about 98%, more preferably, at least about 99% and most preferably at least about 99.9%.
• the purity is measured as described above.
• Example 3 Purification of Paliperidone from PLP-NO by Addition of a Different Solvent.
• Example 4 Purification of Paliperidone from PLP-NO by Slurry in Different Solvents.
• Example 5 Purification of Paliperidone from PLP-NO by Addition of a Different Solvent at a Different Temperature. Slurry of Paliperidone (containing 0.41 % of PLP-NO) in 7 volumes (ml/g) of the indicated solvent was heated to reflux until complete dissolution. The cooled anti- solvent was added at once. The resulting solid was collected by vacuum filtration, and analyzed as shown in the next table.
• Example 6 Purification of Paliperidone from PLP-NO by Addition of a Different Hot Solvent.
• Example 7 Purification of Paliperidone from PLP-NO by Filtration through Activated Carbon
• a slurry of paliperidone (contaminated with 0.67% PLP-NO) in 40 volumes (i.e., g/40 ml) of acetone/water (3:1, volume ratio) was heated to reflux until complete dissolution. After the compound was dissolved, the hot solution was filtrated through hi-flow and cooled in an ice bath. The solid was filtrated and analyzed as shown in the next table.
• Example 9 Purification of Paliperidone from PLP-Car by Addition of a Different Solvent.
• Example 10 Purification of Paliperidone from PLP-Car by Slurrying in Different Solvents.
• Example 11 Purification of Paliperidone from PLP-Car by Addition of a Different Solvent at a Different Temperature.
• Example 12 Purification of Paliperidone from PLP-Car by Addition of a Different Hot Solvent.
• Example 13 Purification of Paliperidone from PLP-Car by Filtration through Activated Carbon
• N/D represents not detected.

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• 2007
  • 2007-08-14 WO PCT/US2007/017956 patent/WO2008021346A2/en active Application Filing
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