Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Particulate form
Patent
1993-11-15
1995-10-10
Page, Thurman K.
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Particulate form
424452, 424455, 424465, 5147722, 5147723, 514774, 514778, 514779, 514781, 514937, A61K 910, A61K 914
Patent
active
054569230
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/JP92/00470 filed Apr. 14, 1992.
TECHNICAL FIELD
The present invention relates to a process for producing a solid dispersion. More particularly, the invention relates to a process for producing a solid dispersion utilizing a twin-screw extruder, which finds application chiefly in the field of pharmaceutical manufacture.
The term `solid dispersion` is used herein to mean a drug-containing pharmaceutical bulk substance comprising the drug dissolved or dispersed in a polymer.
BACKGROUND ART
Solid dispersions are of use for an enhanced solubility of drugs or for controlling the rate of release of a drug from a dosage form or improving the bioavailability of drugs, thus being of significant commercial value.
The conventional technology for the production of a solid dispersion includes a fusion process which is characterized by melting a drug and a polymer together at elevated temperature and, then, cooling the melt to solidify, a solvent process which is characterized by dissolving a drug and a polymer in an appropriate solvent and, then, removing the solvent, and a fusion-solvent process which has the characteristics of said processes.
However, the fusion process has the disadvantage that it cannot be applied to a drug or polymer which is, or is likely to be, thermally degraded.
The solvent process is free from the above-mentioned disadvantage of the fusion process but because it employs an organic solvent such as an alcohol or a chlorine-containing solvent, this process has the following disadvantages.
(1) When an alcohol is used as the solvent, strict measures must be provided for the prevention of an explosion hazard during production.
(2) Since organic solvents have fairly high affinities for the polymer, they cannot be easily removed from the product solid dispersions.
(3) Removal of the solvent necessarily results in its diffusion into the atmosphere to cause an atmospheric pollution.
(4) After removal of the solvent, the solid dispersion adhering intimately to the vessel wall cannot be easily withdrawn from the vessel.
DISCLOSURE OF INVENTION
The object of the present invention is to establish an improved process for producing a solid dispersion which has overcome the above-mentioned inherent disadvantages of the fusion and solvent processes.
The substantive feature of the present invention resides in the processing of the drug, polymer and other components for a solid dispersion by utilizing a twin-screw extruder.
The present invention is now described in detail.
The twin-screw extruder is a forward-discharge extruder-granulator characterized by the use of a couple of screws, which differentiate the machine from the so-called single-screw extruder. To be more specific, the twin-screw extruder comprises a metering feeder unit, a barrel (cylinder), screws, paddle means, screw shafts, barrel heater-cooler means, exit dies (cooling die, heating die, molding die) and extrudate cutter and provides for a free variation of compounding pressure and molding temperature through a choice of screw geometry, rotational speed, and screw elements to be mounted on the screw shafts. Furthermore, if necessary, the barrel can be used in a variety of combinations of length and type according to the intended use and its temperature can also be controlled as desired.
Thus, the twin-screw extruder processes the feed with two screws and provides for change of the combination of axial screw elements so that it has many definite advantages over the single-screw extruder, viz.
(1) In the twin-screw extruder, the respective screws influence each other so that the material is not rotated together with the screws and, hence, the compounding is not much influenced by characteristics of the material. Therefore, the twin-screw extruder is capable of processing an oil-rich or water-rich material which cannot be successfully processed by the single-screw extruder.
(2) Compared with the single-screw extruder, the twin-screw extruder is by far superior in shear force, compounding effect and transpor
REFERENCES:
patent: 4801460 (1989-01-01), Goertz et al.
patent: 4880585 (1989-11-01), Klimesch et al.
patent: 4992100 (1991-02-01), Koepff et al.
patent: 5073379 (1991-12-01), Klimesch et al.
patent: 5102668 (1992-04-01), Eichel et al.
English language Abstract JP-A-62040277. Feb. 1987.
English language Abstract JP-A-58109411. Jun. 1983.
Izumi Shogo
Nakamichi Kouichi
Yasuura Hiroyuki
Nippon Shinyaku Company Limited
Page Thurman K.
Spear James M.
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