Organic compounds -- part of the class 532-570 series – Organic compounds – Unsubstituted hydrocarbyl chain between the ring and the -c-...
Patent
1995-06-09
1998-09-22
Shah, Mukund J.
Organic compounds -- part of the class 532-570 series
Organic compounds
Unsubstituted hydrocarbyl chain between the ring and the -c-...
548500, 564 45, 564213, C07D20932, C07D22324
Patent
active
058115471
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a method of inducing a transition of crystalline state in a crystallizable medicinal substance.
As used in this specification, the term `stable crystal` means any crystal that is in thermodynamically stable crystalline state and the term `metastable crystal` means any crystal that is in thermodynamically unstable crystalline state. The term `crystalline state` is used referring to any of stable crystal, metastable crystal and amorphous (noncrystalline) solid. The term `heterogenous crystal` means a crystal not in a singular crystalline state.
The term `extruder` means any screw extruder that is in broad use chiefly in food industry for the processing of food materials (cereals, proteins, animal meat, fish meat, etc.).
BACKGROUND ART
The conventional technology for inducing a transition of crystalline state in a medicinal substance includes recrystallization, heating, freeze-drying, pulverizing and so on.
However, none of these conventional methods are capable of inducing a transition of crystalline state expediently, efficiently, uniformly and on a mass scale and, therefore, are not well suited for commercial application. One of the reasons for their incapability is that because these technologies are invariably batch processes, large-scale equipment is required for mass processing but the larger the equipment, the greater is the temperature gradient created in the processing load, so that homogeneous crystals cannot be easily obtained. Taking the recrystallization process as an example, judicious selection of the recrystallization solvent, detailed analysis of recrystallizing temperature and other parameters, and accurate control of recrystallization conditions are essential. In the case of freeze-drying, the protracted processing time is also a detracting factor.
The present invention will be clearly seen from the following discussion and the drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic cross-section view of the main part of the extruder used to effect the method of the present invention;
FIG. 2, is a schematic representation of change in crystalline state of the medical substance being processed in the extruder of FIG. 1;
FIGS. 3-10 are powder diffraction patterns, with each figure showing comparative diffraction patterns for various substances prior to and after processing in accordance with the present invention.
DISCLOSURE OF INVENTION
The object of this invention is to provide a method of inducing a transition of crystalline state in a crystallizable medicinal substance which overcomes the disadvantages of the above-mentioned prior art methods. Specifically, the invention has for its object to provide a method of inducing, expediently, efficiently, uniformly, continuously and on a high production scale, a transition of crystalline state, for example:
(1) from a crystallizable active substance in metastable crystalline state or in amorphous solid state to stable crystals,
(2) a crystallizable active substance in stable crystalline state or in amorphous solid state to metastable crystals,
(3) a crystallizable active substance in stable crystalline state or in metastable crystalline state to an amorphous solid, or
(4) a crystallizable active substance in heterogenous crystalline state to homogeneous crystals.
The inventors of this invention found that the above-mentioned object can be accomplished by utilizing an extruder which enables a continuous processing of the load and have arrived at the present invention.
In the pharmaceutical field, few technologies utilizing an extruder are known.
At this junction, the mechanism of the main part (work processing part) of the extruder is briefly described. Generally the main part of an extruder comprises, as illustrated in FIG. 1, a cylindrical structure called `barrel`, a die which corresponds to a delivery port, and a screw. The barrel usually comprises a plurality of unit barrels and the screw extends through them. The screw is available in various types, namely trapezoidal sc
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Obandie et al, J. of Applied Polymer Science, vol. 37, pp. 1713-1726 (1989).
Journal of Pharamaceutical Sciences, vol. 62, No. 1, Jan. 1973 F.W. Goodhart, et al. "Design and Use of A Laboratory Extruder for Pharmaceutical Granulations", pp. 133-136.
Izumi Shougo
Nakamichi Kouichi
Oka Masaaki
Nippon Shinyaju Co., Ltd.
Shah Mukund J.
Wong K.
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