Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Matrices
Reexamination Certificate
1996-02-20
2001-11-06
Kulkosky, Peter F. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Matrices
C424S488000
Reexamination Certificate
active
06312726
ABSTRACT:
This application is a 371 of PCT/JP94/01367 filed August.
TECHNICAL FIELD
The present invention relates to a gastric remaining preparation. More particularly, the present invention relates to a swollen molding that can be manufactured by means of a multi-screw extruder and a gastric remaining preparation comprising the same.
A gastric remaining preparation is a pharmaceutical device adapted to remain afloat on top of the gastric juice and contents and release an active drug substance in situ in a retarded fashion.
The term “swollen molding” is used herein to mean an artifact containing internal pores as swollen and formed under the influence of heat and/or pressure or through other phenomena such as chemical change.
BACKGROUND ART
Being a kind of controlled-release preparation, the gastric remaining preparation offers the advantages of a reduced frequency of administration, sustained effective concentration, and mitigated side effects. In addition, the gastric remaining preparation is more or less indifferent to the gastric emptying rate so that the drug substance may be released in sufficient quantities at the absorption site. Therefore, any gastric remaining preparation is a very useful medical device and this is particularly true for those drug substances which are expected to act directly on the stomach or the upper part of the small intestine.
Among the hitherto-known gastric remaining preparations are the preparation exploiting a hydrophilic colloid (JP-A-58057315), the preparation comprising a hollow molded structure externally coated with an active substance (JP-A-55012411), the one utilizing foamable microcapsules (JP-A-52076418), the one comprising a mixture of a water-soluble polymer and an oil and fat with the specific gravity of the whole mixture having been controlled to not greater than 1 (JP-A-61043108, PCT WO91/06281), and the one comprising foamed ethylcellulose (JP-A-62145014), among others. While some of them are functionally acceptable gastric remaining preparations, many are intricate in structure and destroyed by the peristolic motion of the stomach to lose the expected floatability.
Meanwhile, the multi-screw extruder is a kind of screw kneading extruder which is quite different from the single-screw extruder in performance mode and application. Unlike the single-screw extruder which is a simple kneading extruder, the multi-screw extruder has a mechanism resembling an Archimedian screw pump which delivers a high energy output physically through the intermeshing and mutual interference of a plurality of screws, with the result that the load can be subjected to treatments not provided by the single-screw extruder. The multi-screw extruder has been elaborated chiefly in the food and plastics industries and is in common usage for the processing of food (cereals, protein, animal meat, fish meat, etc.) and the injection molding of plastics.
Technologies utilizing an extruder in the pharmaceutical field are disclosed in PCT WO92/18106, PCT WO093/01472, and JP-A-5194197, among other literature. These technologies are not concerned with intragastric resident preparations but are directed to pharmaceutical preparations differing from gastric remaining preparations in construction and effect.
Known in the field of food are several technologies by which swollen moldings are manufactured from certain food materials (e.g. starch materials) using a multi-screw extruder (JP-A-5284926, JP-A-5192083, JP-A-5023125, JP-A-4051849, JP-A-1252267, JP-A-61009253, etc.). However, these technologies are invariably designed to solve the problems characteristic of food industry (promotion of appetite, improvement of appearance, etc.) and belong to a different technical field.
Also known is a technology wherein a swollen molding called an interpenetrating polymer network structure composed predominantly of a lactic acid type polymer (e.g. polylactic acid) is provided by means of a screw extruder (JP-A-5177734). However, this swollen molding is designed for use as an absorbent or filter material for oil and body fluids. Moreover, swollen moldings of this type have a high affinity for water so that they are not adaptable to gastric remaining preparation.
DISCLOSURE OF INVENTION
The primary object of the present invention is to provide a gastric remaining preparation which is quite different in structure from any conventional gastric remaining preparation.
The inventors of the present invention who had been assiduously exploring the utility of a multi-screw extruder (hereinafter referred to briefly as an extruder) in the pharmaceutical field arrived at a gastric remaining preparation meeting the above object and completed the present invention.
The gastric remaining preparation of the present invention (hereinafter referred to briefly as the preparation of the invention) comprises a swollen molding of the present invention (hereinafter referred to as the swollen molding of the invention). The preferred preparation of the invention is a preparation having an apparent density of less than 1.
The swollen molding of the invention is an expanded structure having a mesh-like cross-section and an apparent density of less than 1, which structure being predominantly composed of an acid-resistant polymer compound and additionaly containing at least an auxiliary blowing agent and a drug substance. Because of its being mesh-like in cross-section, the swollen molding of the invention has a multiplicity of microfine internal pores which are continuous or discontinuous.
Credit is due to the inventors of the present invention for the first creation of a gastric remaining preparation by means of an extruder.
REFERENCES:
patent: 4493807 (1985-01-01), Vyvial et al.
patent: 4738817 (1988-04-01), Wittwer et al.
patent: 4880585 (1989-11-01), Klimesch et al.
patent: 5073379 (1991-12-01), Klimesch et al.
patent: 0 326 816 A (1989-08-01), None
Izumi Shougo
Nakamichi Kouichi
Yasuura Hiroyuki
Graham & James LLP
Kulkosky Peter F.
Nippon Shinyaku Co. Ltd.
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