Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D237/00—Heterocyclic compounds containing 1,2-diazine or hydrogenated 1,2-diazine rings
  • C07D237/26—Heterocyclic compounds containing 1,2-diazine or hydrogenated 1,2-diazine rings condensed with carbocyclic rings or ring systems
  • C07D237/30—Phthalazines
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/395—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
  • A61K31/40—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins having five-membered rings with one nitrogen as the only ring hetero atom, e.g. sulpiride, succinimide, tolmetin, buflomedil
  • A61K31/401—Proline; Derivatives thereof, e.g. captopril
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P3/00—Drugs for disorders of the metabolism
  • A61P3/06—Antihyperlipidemics
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P43/00—Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D207/00—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom
  • C07D207/02—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D207/30—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having two double bonds between ring members or between ring members and non-ring members
  • C07D207/34—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having two double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms

Definitions

• the invention relates to a stable amorphous form of atorvastatin calcium and to packaging procedures that maintain stability of the compound during storage.
• Atorvastatin calcium is a drug compound that is used as a lipid-lowering agent, for treating hypercholestrolemia.
• the compound has the chemical name [R-(R*,R*)]-2-(4-fluorophenyl)- ⁇ , ⁇ -dihydroxy-5-(1-methylethyl)-3-phenyl-4- [(phenylamino)carbonyl]-1 H-pyrrole-1-heptanoic acid, calcium salt (2:1).
• Pharmaceutical products containing crystalline atorvastatin calcium trihydrate are sold using the trademark LIPITOR.
• Atorvastatin calcium exists in various crystalline and amorphous forms.
• the amorphous form is of interest, due at least in part to its enhanced solubility as compared to crystalline forms, a higher solubility thought to provide an improved bioavailability profile.
• a process for preparing amorphous atorvastatin calcium from crystalline form I of the compound is described in International Patent Publication WO 97/03960, which states that prior processes had prepared the amorphous compound but, after the advent of crystalline forms, there was a problem with producing the amorphous material reproducibly.
• a number of subsequent patents and applications relate to different processes for producing amorphous atorvastatin calcium.
• the invention includes amorphous atorvastatin calcium having a water content about 2 to about 8 percent by weight. In another aspect, the invention includes amorphous atorvastatin calcium having a water content about 2 to about 8 percent by weight, and having a total organic compound impurity content less than about 1 area-percent by high performance liquid chromatography.
• the invention includes amorphous atorvastatin calcium having a water content about 2 to about 8 percent by weight, and further comprising a pharmaceutical excipient or additive, an example of a useful additive being an antioxidant, such as about 0.05 to about 0.2 percent by weight of butylated hydroxyanisole, butylated hydroxytoluene, propyl gallate, or a mixture of two or more thereof.
• a useful additive being an antioxidant, such as about 0.05 to about 0.2 percent by weight of butylated hydroxyanisole, butylated hydroxytoluene, propyl gallate, or a mixture of two or more thereof.
• the invention includes amorphous atorvastatin calcium having a water content about 2 to about 8 percent by weight, being packaged in a first closed container that is substantially non-permeable to moisture, the first container being disposed within a second closed container that is substantially non-permeable to moisture, and space between the containers containing at least one of an inert gas, a desiccant, and an oxygen absorber.
• the invention includes amorphous atorvastatin calcium having a water content about 2 to about 8 percent by weight, being packaged in a first closed container that is substantially non-permeable to moisture, the first container being disposed within a second closed container that is substantially non-permeable to moisture, and the second container being disposed within a third closed container that is substantially non-permeable to moisture, and space between any two containers containing at least one of an inert gas, a desiccant, and an oxygen absorber.
• Another aspect of the invention includes amorphous atorvastatin calcium having a water content about 2 to about 8 percent by weight, prepared by a process comprising:
• Fig. 1 is an X-ray diffraction pattern for the amorphous atorvastatin calcium product of Example 4.
• Fig. 2 is a schematic representation of a process for preparing atorvastatin calcium.
• the present invention is based on a finding that amorphous atorvastatin calcium having a moisture content about 2 to about 8 percent by weight has an enhanced stablility during storage.
• One aspect of the invention therefore, is an amorphous atorvastatin calcium having this moisture content.
• Another aspect of the invention is a process for preparing amorphous atorvastatin calcium having a moisture content about 2 to about 8 percent by weight.
• An embodiment of a process for the preparation of a stable amorphous atorvastatin calcium having moisture content about 2-8 percent w/w comprises the steps of: i. dissolving atorvastatin calcium in an ester solvent, optionally adding a pharmaceutical excipient or additive; ii. removing the solvent to produce an amorphous residue; iii. optionally micronizing the residue to produce a desired particle size distribution, optionally followed by drying; and iv. exposing the residue to a humidified atmosphere to produce the stable amorphous atorvastatin calcium having a moisture content of about 2 to about 8 percent by weight.
• the process of the present invention involves dissolving atorvastatin calcium in an ester solvent, with or without the addition of pharmaceutical excipients or additives.
• Useful ester solvents include but are not limited to ethyl acetate, f-butyl acetate, propyl acetate, and the like.
• the concentration of atorvastatin calcium in the solution will frequently range from 6 to 9% w/v, but the process can be successfully conducted using other concentrations. i he dissolution temperature frequently will range from 50 to 85°C. Suitable temperatures for particular atorvastatin calcium-solvent mixtures will vary for different solvents due to the variations in atorvastatin solubility in individual solvents. The temperature will be chosen to obtain a clear solution having the desired solute concentration.
• one or more pharmaceutical excipients or additives, or mixtures thereof can be dissolved in the solution, or solutions of the excipients or additives can be mixed with the atorvastatin calcium solution.
• the pharmaceutical excipients or additives that can be used include but are not limited to antioxidants, surfactants, dispersants, lubricants, and other stabilizing additives.
• suitable antioxidants include but are not limited to butylated hydroxyanisole, butylated hydroxytoluene, propyl gallate and the like; including these substances can provide additional storage stability for the amorphous atorvastatin calcium.
• the concentration of antioxidant in the final atorvastatin calcium product can be about 0.05 to about 0.2 percent by weight, and will frequently be less than about 0.15 percent by weight, while concentrations of other excipients and additives can vary widely.
• the pharmaceutical excipient or additive can be added to the solution of ester solvent containing atorvastatin calcium at temperatures that will not affect the stability of the excipient or additive, with mixing sufficient to produce a homogenous solution.
• the solvent can be removed from the solution by any desired technique, such as agitated thin film drying, spray drying, rotational evaporation (such as using a Buchi Rotavapor), spin-flash drying, fluid-bed drying, lyophilization or other techniques known to those skilled in the art.
• agitated thin film dryer a temperature of the apparatus from about 50 to about 120 0 C has been found useful, for drying conducted under a vacuum less than about 650 mm Hg.
• the temperature and vacuum conditions can be varied depending upon the solvent used and the characteristics of the apparatus. After the solvent has been removed, it frequently is desired to reduce the particle sizes of the residue, since the subsequent production of dosage forms such as tablets generally requires fine particle sizes.
• the desired particle size distribution is expressed by D 90 ⁇ 20 ⁇ m, meaning that 90 volume percent of the particles have diameters less than 20 ⁇ m. In certain instances a desired particle size distribution is D 90 ⁇ 15 ⁇ m.
• Such particle size information can be obtained using a Malvern laser light scattering particle size analyzer, sold by Malvern Instruments Ltd. of Worcestershire, United Kingdom. Many techniques are useful for particle size reduction, including jet milling. In an embodiment, the residue is micronized in a jet mill using gases such as air or nitrogen at pressures about 4.5 to 6 kg/cm 2 .
• the micronized amorphous atorvastatin calcium can optionally be dried to remove residual solvent using a suitable drying process, such as tray drying, fluid bed drying, microwave drying, belt drying, rotary drying, aerial drying, oven drying and other drying processes known in the art, with or without application of vacuum and/or under inert conditions.
• a suitable drying process such as tray drying, fluid bed drying, microwave drying, belt drying, rotary drying, aerial drying, oven drying and other drying processes known in the art, with or without application of vacuum and/or under inert conditions.
• the micronized amorphous atorvastatin calcium is dried at a temperature between about 25 to 8O 0 C over a period of 4 to 7 hours, to produce a residual solvent content less than about 5000 ppm by gas chromatography.
• the temperatures and times for drying will be chosen based on the properties of the solvent to be removed, and must be selected to not affect the amorphous atorvastatin calcium itself. Some solvent removal techniques will produce a residue already having a low solvent content
• the amorphous atorvastatin calcium is exposed to a humidified atmosphere, such as air or an inert gas.
• a humidified atmosphere such as air or an inert gas.
• the relative humidity in the humidified atmosphere typically ranges from about 60 to about 90% to afford the final desired moisture content. Exposure will be continued for a time sufficient to produce the moisture content of the final amorphous atorvastatin calcium between about 2 to about 8 percent by weight, and that time will vary depending upon the mode of exposure and the moisture content of the atmosphere. Determination of an appropriate time is a matter of simple experimentation.
• drying and exposure to humidity does not need to be performed sequentially.
• the drying operation is performed by passing humidified gas, such as air or nitrogen, through or over the amorphous atorvastatin calcium, at temperatures suitable for removing the solvent.
• humidified gas such as air or nitrogen
• a further aspect of the present invention is providing a packaging environment for the stable amorphous atorvastatin calcium having the moisture content about 2-8 percent w/w, which is useful on a commercial scale and preserves the moisture and impurity content.
• the packaging environment for the storage of the stable amorphous atorvastatin calcium of this invention comprises packaging amorphous atorvastatin calcium with a moisture content of about 2 to 8 percent w/w into non- permeable containers with or without an oxygen absorbent, with or without an inert gas environment, and with or without a desiccant.
• stability of amorphous atorvastatin calcium is maintained during storage by a procedure comprising packaging amorphous atorvastatin calcium having a moisture content of about 2 to 8 percent w/w into a non-moisture permeable container with or without inert gas, followed by placing into a second non-moisture permeable container containing a desiccant pouch, with or without an oxygen absorbent, inert gas, or both, and further placing the second container into a non-moisture permeable container containing a desiccant and an inert gas.
• Non-moisture permeable containers include but are not limited to polyethylene or other polymer bags, including laminated bags, glass containers, metal containers, rigid plastic containers and the like.
• the polymer bags can be clear or transparent, or have colors such as black or white.
• Useful inert gases include, but are not limited to, nitrogen and argon.
• Useful oxygen absorbers include, but are not limited to, powdered iron compositions and compositions containing unsaturated organic compounds; several types of oxygen absorber products are commercially available, including a product that absorbs both moisture and oxygen.
• Suitable desiccants include chemically inert substances such as dried silica gel or a zeolite. The desiccants and oxygen absorbers will be contained in forms such as pouches or bags that are permeable to gases, such a cloth bags, paper bags, or porous plastic containers.
• storage-stable amorphous atorvastatin calcium is achieved by the procedure of placing amorphous atorvastatin calcium having a moisture content of about 2 to 8 percent w/w into a non-permeable container such as a polyethylene bag with or without an inert gas, followed by placing the container into a second non-permeable container such as a polyethylene bag optionally containing a desiccant pouch, with or without an oxygen absorbent, an inert gas, or both, then further placing the second container into a third non- permeable container such as a triple laminated polyethylene-aluminum foil bag containing a desiccant pouch and purged with an inert gas, then finally placing the triple laminated bag into a high density polyethylene storage container (HDPE) and sealing the container.
• the bags will each be sealed, such as using a tie or adhesive, heat welding, etc.
• amorphous atorvastatin calcium having a moisture content between about 2 and about 8 percent by weight are placed into a first polyethylene bag, the bag is purged with nitrogen, excess nitrogen is removed, and the bag is sealed.
• the first bag is then placed into a second polyethylene bag, the second bag is purged with nitrogen, oxygen absorber pouches (having the trademark AGELESS, manufactured by Mitsubishi Gas Chemical Company, Tokyo, Japan and rated for absorbing 10 liters of oxygen) and a 100 gram silica gel desiccant pouch are added, and the second bag is sealed.
• oxygen absorber pouches having the trademark AGELESS, manufactured by Mitsubishi Gas Chemical Company, Tokyo, Japan and rated for absorbing 10 liters of oxygen
• the second bag is placed into a triple laminated bag containing a 100 gram silica gel desiccant pouch, then the triple laminated bag is purged with nitrogen and heat sealed.
• a triple laminated bag For shipping, one or more triple laminated bags will be placed into a sealed container having adequate physical strength, such as a high density polyethylene drum.
• amorphous atorvastatin calcium of the present invention is well suited for pharmaceutical formulations.
• amorphous atorvastatin calcium for use in pharmaceutical formulations is desired to have a total organic impurity content no greater than about 1 area-percent, as determined using high performance liquid chromatography.
• the present processes for the preparation and packaging of stable amorphous atorvastatin calcium are simple, cost-effective, and non-hazardous.
• the solvent was distilled from the filtrate under vacuum at temperatures below 6O 0 C, then 52 ml of methanol were added and again the solvent was distilled, and this was repeated two additional times with 52 ml portions of methanol. Finally, the solvent was distilled completely to produce 18 ⁇ 2 grams of the title compound having a moisture content by the Karl Fischer method not more than about 5% by weight and a purity of at least about 95% by high performance liquid chromatography.
• reaction mass was diluted with 1100 ml of water.
• the pH of the reaction mass was adjusted to 7-8 by adding a solution of sodium carbonate (31.6 grams) in water (158 ml) at 10-15°C.
• the formed solid was filtered and washed with 550 ml of water.
• Wet solid was dissolved in a mixture of 924 ml of acetonitrile and 365 ml of water at 70-75 0 C.
• the solution was cooled to 25-30 0 C for about 1-2 hours, and the precipitated solid was filtered and washed with a mixture of 146 ml of acetonitrile and 73 ml of water.
• the washed solid was dried at 50-60 0 C for about 8-12 hours to yield 85 grams of the title compound.
• a solution of sodium hydroxide (1 gram) in water (10 ml) was further added, and the temperature of the reaction mass was raised to 70-80 0 C for about 1 hour.
• the reaction mass was filtered on a flux calcined diatomaceous earth bed at 60-65°C and washed with acetonitrile (200 ml). 2400 ml of water were added to the filtrate at 25-30°C followed by addition of a solution of sodium hydroxide (0.4 grams) in water (4 ml) and heating to 70-80 0 C for 6-8 hours.
• the reaction mass was cooled to 25-30°C for about 2 hours, and the obtained solid was filtered and washed with water (500 ml).
• the solid was dried until its moisture content was less than about 2% by weight.
• the solid was dissolved in 1600 ml of ethyl acetate at 60-70°C, and the solution was then cooled immediately to 25-35 0 C.
• the organic layer was processed through an agitated thin film dryer at 68-78°C under reduced pressure and the solid amorphous output material was micronized to a particle size distribution having 90 volume percent of the particles with diameters less than 15 ⁇ m.
• the material was dried in a fluidized bed dryer at 60 to 75 0 C for 4 hours and then humidified air (70- 80% relative humidity) was passed over the solid for 2 to 4 hours to produce 100 grams of amorphous atorvastatin calcium having a moisture content of 5.4 percent by weight by the Karl Fischer method, with a 99.6% organic compound purity by high performance liquid chromatography ("HPLC").
• HPLC high performance liquid chromatography
• 160 g of atorvastatin calcium was added to 1600 ml of ethyl acetate followed by heating to a temperature of about 65 to 75°C to obtain a clear solution, then the clear solution was cooled to a temperature of about 25 to 30 0 C.
• 0.2 g of butylated hydroxyanisole were added to the above solution followed by stirring for about 5 to 10 minutes.
• the organic layer was filtered through celite followed by washing with 160 ml of ethyl acetate and the organic layer was passed through an agitated thin film drier at a temperature of about 73 to 78°C by applying vacuum of about 650 mm Hg.
• the solid material that was obtained from the agitated thin film drier was subjected to micronization in a jet mill to produce a solid material having a particle size distribution of Dg 0 ⁇ 15 ⁇ m.
• the solid material was then dried using a fluid bed drier at a temperature of about 68 to 75 0 C for 4 hours with simultaneous passing of humidified air having a relative humidity of 70 to 80% to yield a stable amorphous atorvastatin calcium having a moisture content of 3 to 8 percent w/w. (Yield: 80%).
• Physical characteristics of the micronized product were as follows:
• amorphous atorvastatin calcium having a 6 percent w/w water content was initially packed in a polyethylene bag, which was then tied; 2) the tied polyethylene bag was placed in a black polyethylene bag with a silica gel pouch under a nitrogen atmosphere and then sealed; 3) the sealed black polyethylene bag was placed in a triple laminated bag along with a silica gel pouch, was purged with nitrogen, and sealed; and 4) the sealed laminated bag was stored in a HDPE drum.
• Stability of the amorphous atorvastatin calcium during storage at 40 0 C and 75% relative humidity is shown in the following table, where water was determined by the Karl Fischer method, and total organic impurities are expressed as area- percent, as determined by high performance liquid chromatography.
• Stability data of the amorphous atorvastatin calcium during storage at 2 to 8 0 C is shown in the following table.
• amorphous atorvastatin calcium having a 2 percent w/w moisture content was placed in a white polyethylene bag, the bag was purged with nitrogen, and then the bag was tied; 2) the tied white polyethylene bag was placed into a black polyethylene bag, along with a silica gel pouch and and a bag of oxygen absorbent, then the black bag was purged with nitrogen and sealed; 3) the sealed black polyethylene bag was placed into a triple laminated bag along with a silica gel pouch, and then the laminated bag was purged with nitrogen and sealed; and 4) the sealed laminated bag was stored in a HDPE drum.
• a commercial-sized batch of amorphous atorvastatin calcium was packaged as follows: a) amorphous atorvastatin calcium having a 6 percent w/w water content was initially placed into a clear polyethylene bag, air was removed, and the clear polyethylene bag was tied; b) the tied clear polyethylene bag was placed into a black polyethylene bag along with a silica gel pouch and a package of oxygen absorbent, and then the black polyethylene bag was purged with nitrogen and sealed; and c) the sealed black polyethylene bag was placed in a triple laminated bag along with a silica gel pouch, then the laminated bag was purged with nitrogen and sealed.

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• 2005
  • 2005-09-29 JP JP2007534782A patent/JP2008514722A/ja active Pending
  • 2005-09-29 WO PCT/US2005/035094 patent/WO2006039441A2/en not_active Ceased
  • 2005-09-29 US US11/576,396 patent/US20080009540A1/en not_active Abandoned
  • 2005-09-29 EP EP05803604A patent/EP1793815A4/en not_active Withdrawn
  • 2005-09-29 CA CA002582449A patent/CA2582449A1/en not_active Abandoned
  • 2005-09-29 KR KR1020077007918A patent/KR20070106680A/ko not_active Ceased
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