Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D409/00—Heterocyclic compounds containing two or more hetero rings, at least one ring having sulfur atoms as the only ring hetero atoms
  • C07D409/02—Heterocyclic compounds containing two or more hetero rings, at least one ring having sulfur atoms as the only ring hetero atoms containing two hetero rings
  • C07D409/06—Heterocyclic compounds containing two or more hetero rings, at least one ring having sulfur atoms as the only ring hetero atoms containing two hetero rings linked by a carbon chain containing only aliphatic carbon atoms
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/14—Particulate form, e.g. powders, Processes for size reducing of pure drugs or the resulting products, Pure drug nanoparticles
  • A61K9/16—Agglomerates; Granulates; Microbeadlets ; Microspheres; Pellets; Solid products obtained by spray drying, spray freeze drying, spray congealing,(multiple) emulsion solvent evaporation or extraction
  • A61K9/1682—Processes
  • A61K9/1688—Processes resulting in pure drug agglomerate optionally containing up to 5% of excipient
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D9/00—Crystallisation
  • B01D9/0004—Crystallisation cooling by heat exchange
  • B01D9/0009—Crystallisation cooling by heat exchange by direct heat exchange with added cooling fluid
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D9/00—Crystallisation
  • B01D9/005—Selection of auxiliary, e.g. for control of crystallisation nuclei, of crystal growth, of adherence to walls; Arrangements for introduction thereof

Definitions

• the present invention relates to a process for the crystallisation of a chemical substance, and more particularly a substance to be used as a pharmaceutically active agent.
• Crystallisation is a well known technique for the purification of chemical compounds. Crystalline products prepared using traditional batch methodology may vary; for example in the degree of agglomeration experienced and the habit and size of individual crystals so formed. Moreover, in some circumstances, conventional batch mode crystallisation may give poor results, i.e. produces oils or crystals containing occluded impurities. There is therefore a need for a crystallisation process that gives rise to products of uniform and consistently small crystal size without the problems of batch processing, especially oiling or solvent inclusion. This is particularly true for pharmaceutically active compounds which might otherwise have to be milled to improve their bio-availability, or to increase their suitability in processing, e.g. the electrostatic deposition of active ingredients in tablet manufacture.
• a process for the continuous crystallisation of an organic chemical compound which comprises contacting a stream of either the compound or a salt thereof dissolved in a solvent with a stream of anti-solvent or colder solvent, or a solution of an appropriate acid or base, and separating off the crystals formed.
• the solute/solvent/antisolvent system will be one which has a fast precipitation time, as this gives rise to particularly small crystals.
• 'precipitation time' we mean the time taken to observe precipitation in a mixed system e.g. cloudiness.
• Precipitation times can be determined by mixing and observing precipitation in individual solvent systems.
• the precipitation time will be less than 1 minute, especially less than 5 seconds, and particularly less than 1 second.
• Precipitation times may be varied by adjusting the concentration of solute, the rates of flow of solution and anti-solvent, and the temperatures of the solvent and anti-solvent. It should be recognised that the process of crystallisation can involve the initial formation of amorphous solid particles which rapidly change into a crystalline form.
• the contacting process may prove satisfactory for the contacting process to be undertaken using a simple three-way pipe connection (for example a T or ⁇ - connection) provided that appropriate flow rates are used.
• a simple three-way pipe connection for example a T or ⁇ - connection
• the contacting process is undertaken using conditions of high shear and turbulence.
• Mixing devices suitable for use in this invention include known in-line mixers, e.g. of the type in which one or more turbulence-creating elements are located within a pipeline through which the components are caused to flow.
• Another suitable type of mixer is a homogeniser, e.g. of the type in which two liquid phases are forced under pressure through a biased valve.
• Suitable mixing devices may also include cavities subjected to high turbulence and or shear stress by means of turbines, propellers etc.
• mixers for creating conditions of high shear and turbulence are a chamber wherein introduced fluids are subjected to intense rotational swirling, for example a vortex chamber of the type disclosed generally in EP-
• the vortex chamber comprises a chamber of substantially circular cross section, e.g. generally cylindrical in shape, and having tangential inlets and an axial outlet.
• the components are introduced via the tangential inlets where they experience swirling and intense mixing as they radially accelerate towards the centrally located outlet.
• a vortex mixer e.g. a Power Fluidics mixer
• the mixing is carried out under controlled residence times in the mixer as this gives rise to a product of uniform crystal size. Fast precipitation times give rise to particularly small crystals.
• Each stream is fed at high velocity into the central mixing chamber where it is mixed and accelerated towards to the central exit orifice.
• the internal diameter of such a vortex chamber is about 8 mm, and its height about 1mm.
• a combination of small mixing chamber volume (approx. 0.05-0. lml) and high throughputs preferably between 0.5L and 2L/min) generate typical residence times of less than 10ms in a steady-state environment where all elements of the mixed stream experience
• the mixed stream of solute in solvent and anti-solvent is cooled during the mixing process and/or subsequent to it before the crystalline material is separated from the solvent stream.
• the outlet flow from the mixer e.g. the Power Fluidic mixer
• the tubular reactors e.g. a flexible tubular reactor
• such tubular reactors are cooled.
• the compound to be crystallised is an active ingredient for a pharmaceutical composition.
• Particularly preferred compounds for crystallisation in accordance with the process of this invention are: Eprosartan methanesulphonate - (-(E)-(-[[2-butyl-l-[(4-carboxyphenyl)methyl]-lH- imidazol-5-yl]methylene]-2-thiophenepropanoic acid methanesulphonate); and Nabumetone - 4-(6-methoxy-2-naphthalenyl)-2-butanone.
• the process is one in which the compound to be crystallised is the same as the compound dissolved in the solvent prior to addition of the anti-solvent (e.g. neutral molecule, free acid or base, acid-addition salt or base-addition salt).
• the process can also be used where a solution containing the free acid or base of a compound is mixed under conditions of high turbulence with a solvent containing either acid or base to form a salt, or alternatively where a solution of a salt of a compound is rapidly mixed under conditions of high turbulence with a solvent containing an acid or base.
• Figure 1 Shows a mixing device in the form of a vortex chamber having two tangential inlets and an axial outlet;
• Figure 2 Shows crystals of Eprosartan methanesulphonate obtained bv batch crystallisation;
• Figure 3 Shows crystals of Eprosartan methanesulphonate prepared by continuous crystallisation using a vortex mixer
• Figure 4 Shows a comparison of particle sizes of Eprosartan methane sulphonate produced by continuous crystallisation and batch crystallisation;
• Figure 5 Shows crystals of Nabumetone obtained by batch crystallisation
• Figure 6 Shows crystals of Nabumetone prepared by continuous crystallisation using a vortex mixer
• Figure 7 Shows a comparison of particle sizes of Nabumetone crystals produced by continuous crystallisation and batch crystallisation.
• Eprosartan methanesulphonate (-(E)-(-[[2-butyl-l-[(4-carboxyphenyl)methyl]-lH- imidazol-5-yl]methylene]-2-thiophenepropanoic acid methanesulphonate) is described in U.S. 5,185,351/EP 0 403 159.
• the crystallised eprosartan methanesulphonate has a ago of less than 10 microns.
• the solution of the solute is a solution of Eprosartan methanesulphonate in acetic acid, preferably at an elevated temperature for example from 20°C to 100°C, preferably 70°C to 90°C and especially between 75 to 85°C.
• the solution of the solute is reasonably concentrated, for example between 5 and 40% w/v, preferably between 10 and 30% w/v and especially between 15% and 25% w/v.
• the anti-solvent is ethyl acetate or tert-butyl methyl ether (TBME), especially TBME.
• TBME tert-butyl methyl ether
• the anti-solvent is used in a significant excess to the solution of solute, for example from a 3-fold to a 30-fold excess, preferably 6-fold to a 25 -fold excess.
• the anti-solvent is mixed at a temperature from -20°C to 80°C, preferably 0°C to 30°C. most preferably around 10 °C to 20°C.
• the contacting process is undertaken in a vortex mixer. It has been found that using a solution of Eprosartan methanesulphonate (concentration of 20%w/v) dissolved in acetic acid at around 80°C and using an anti- solvent of tert-butyl methyl ether at around 20°C, that crystals of a particularly advantageous small and uniform size and consistency are obtained ( see Figure 3). Particle size distributions were found to be narrow, uni-modal and near symmetrical with d, 0 , d 50 and d 90 values of 1. 3.5 and 7 micron respectively. There is good demonstrated reproducibility with no observed agglomeration.
• Nabumetone - (4-(6-methoxy-2-naphthalenyl)-2-butanone) is described in US patent 4,061 ,779.
• the crystallised Nabumetone has a needle length of less than 20 microns.
• the solution of the solute is a solution of Nabumetone in propan-2-ol, preferably at an elevated temperature for example from 20°C to 82°C and more preferably between 50°C to 77°C.
• the solution of the solute is at a concentration of 5 to 30%w/v, more preferably between 5 and 10%w/v.
• the anti-solvent is water.
• the anti-solvent is used in an excess to the solution of solute, for example from a 4-fold to a 30-fold excess, preferably 4- fold to 10-fold.
• the anti-solvent is mixed at a temperature from 0°C to 50°C, more preferably 6°C to 27 ⁇ >C.
• the contacting process is undertaken in a vortex mixer.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Bioinformatics & Cheminformatics (AREA)
• Health & Medical Sciences (AREA)
• Physics & Mathematics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Crystallography & Structural Chemistry (AREA)
• Thermal Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Animal Behavior & Ethology (AREA)
• Epidemiology (AREA)
• Pharmacology & Pharmacy (AREA)
• Medicinal Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Plural Heterocyclic Compounds (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=10849355

Family Applications (1)

Country Status (5)

Families Citing this family (10)

Family Cites Families (3)

• 1999
  • 1999-03-10 GB GBGB9905512.1A patent/GB9905512D0/en not_active Ceased
• 2000
  • 2000-03-09 AU AU29326/00A patent/AU2932600A/en not_active Abandoned
  • 2000-03-09 EP EP00907864A patent/EP1165197A1/en not_active Withdrawn
  • 2000-03-09 JP JP2000603770A patent/JP2002538227A/ja not_active Withdrawn
  • 2000-03-09 WO PCT/GB2000/000866 patent/WO2000053282A1/en not_active Application Discontinuation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events