Stock material or miscellaneous articles – Hollow or container type article – Nonself-supporting tubular film or bag
Reexamination Certificate
2000-06-29
2004-09-14
Pyon, Harold (Department: 1772)
Stock material or miscellaneous articles
Hollow or container type article
Nonself-supporting tubular film or bag
C524S047000, C424S451000, C424S452000, C424S455000, C424S456000, C514S962000
Reexamination Certificate
active
06790495
ABSTRACT:
The invention relates to a method for manufacturing a shape body containing a starch, a homogenised mass containing starch and a device for manufacturing a soft capsule according to the preambles of the independent claims.
Form bodies from biodegradable materials for reasons of environmental protection have been of extraordinary interest for a long time. As a result of the problems with BSE in particular capsules with a capsule casing of gelatine-free materials have been gaining importance for the administration of pharmaceutically effective substances.
In a series of publications the manufacture of insert capsules from starch are described, such as in EP 118 240 and U.S. Pat. No. 4,738,724. In insert capsules are premanufactured as a two-part casing with the injection moulding method, where appropriate after intermediate storage filled with highly viscous or solid active substances. On account on unsealedness of the insert connection insert capsules are not suitable for low viscous fluids. Furthermore the manufacturing process of a filled insert capsule is complicated and expensive since the working steps of manufacture and filling the capsule casing must be carried out separate from one another.
For pumpable, in the broadest sense fluid capsule content materials, capsules with a one-part capsule casing of gelatine have proven themselves and these may be manufactured in continuous automatisable methods. The manufacture of the capsule casing and the filling of this at the same time is effected in a single working step. In this continuous, 1-step method shape parts are manufactured from which the capsule casing during and after the filling are joined together by welding the outer edges of the shape parts. The shape part manufacture is effected either by way of diverging and converging forms, such as with the Norton, Banner or Schering process or by way of rotating shaping drums, as is e.g. realised in the rotary die process and in the Accogel method (“Die Kapsel” Fahrig/Hofer—Publisher, Stuttgart 1983; Lachmann/Liebermann/Kanig, “The Theory and Practice of Industrial Pharmacy”; Third Edition, Philadelphia 1986). The filling is effected with the help of metering pumps which deliver a defined quantity of active substance during the punching out and welding of the shape parts for forming a one-piece capsule casing. The welding, i.e. the forming of the seams is effected generally by way of pressure and heat. The manufacturing costs are considerably reduced with respect to two-part insert capsules.
U.S. Pat. No. 5,342,626 describes the manufacture of capsules in the rotary die process, wherein the capsule casing material consists of carrageen, mannan gums, such as e.g. galactomannans and glucomannans, gelan or mixtures amongst one another. These macromolecular vegetable biopolymers are however not acceptable with respect to cost since the raw materials are too expensive.
The manufacturing process for one-part capsules sets a series of demands on the capsule casing material. One of the main preconditions is the capability of the capsule casing material to form highly elastic “endless” tapes with a sufficient strength. The capsule casing must when required dissolve rapidly in the stomach and intestinal tract in order to be able to release the active substances. The capsule casing material must be weldable. The molecules of the material forming the shape parts, in particular the macromolecules of the polymer should at the location of the seam ideally penetrate in order to ensure a sufficient stability of the seam location. Gelatine fullfills all these conditions in an almost ideal manner and until now could not be replaced as a material for one-part gelatine capsules.
Under the criteria of availability and cost starch for the manufacture on one-part capsule casings is also a desirable initial material.
The manufacture of starch films has already been described several times, the combination of properties which such a starch film must have for manufacturing one-part capsules has not been achieved up to now.
EP 474 705 describes a method for manufacturing starch shape bodies by extrusion of a starch molten mass. The starch molten mass contains starch with an amylose content over 50% and aggregates. From the molten mass, before, during and/or after the extruding the water is removed by applying a vacuum. The foils extruded from this material have an elongation at rupture between 80 and 200%. Starches with a high amylose content are not suitable as capsule casing materials since the tendency of the amylose chains to retrograde stands in the way of a quick dissolving of the capsule casing.
EP 0397 819 discloses a method for manufacturing thermoplastically processable starch, wherein the crystalline part in the starch lies below 5%. The method consists of mixing native starch with at least 10% by weight of an aggregate which has a solubility parameter of at least 30.7 (MPa)
1/2
. The mixture with the supply of heat is conveyed into a molten mass at a temperature between 120° C. and 220° C. The water content of the starch already in the molten mass is reduced to below 5%. The molar mass of the applied starch before conveying into the thermoplastic condition is larger than 1,000,000 Daltons, preferably between 3,000,000 Daltons and 10,000,000 Daltons. Although this method yields a thermoplastic starch with a good workability into shape bodies which have a sufficient strength, the elongation at rupture of the shape bodies manufactured with this thermoplastic starch only reaches values between 40 and 55%. The elasticity of the starch film is thus to low for the manufacture of one-part capsule casings in a continuous method and leads to a tearing of the shape parts on manufacture or to a tearing of the finished capsule.
The starch film which is produced according to the method disclosed in EP 397 819 furthermore also does not show the weldability or strength of seam which would be sufficient for the demands with respect to the quality on one-part capsule casings.
EP 304 401 likewise describes a method for manufacturing shaped objects from starch. The thermoplastic starch molten mass required for this is manufactured from a pre-treated starch. The destructurisation (destruction of the crystalline region) of the native starch and the subsequent homogenisation (conveying into the thermoplastic condition) in each case takes place at temperatures between 120° C. and 190° C. in a closed vessel with a water content between 10 and 20%. The elongation at rupture of starch films manufactured according to this method is not sufficient for the production of one-part capsule casings in a continuous method. The starch films show furthermore also an insufficient weldability and seam strength.
EP 0 542 155 discloses biodegradable shaping masses which amongst other things are suitable for the manufacture of film.
The shaping masses apart from thermoplastically processable starches contain cellulose derivatives. The elongation at rupture exceeds the value of 85% but not that which is sufficient for the manufacture of one-part capsule casings in a continuous method. The weldability of the films is unsatisfactory. Many of the polymer blends disclosed in EP 542 155 contain substances which are not allowed for pharmaceutical application or for foodstuffs.
WO 97/35537 discloses one-part capsules manufactured by way of rotating shaping drums and containing jellied starch. The teaching of the part etching of the film surface disclosed here has shown to be disadvantageous for the manufacture of one-part capsules with respect to the transport and pressure stability (on pressing the capsules out of the blister packages) since the capsule casings at the region of the seam location by way of this become too soft and flexible.
The object of the present invention is to avoid the problems of the state of the art.
In particular the object of the present invention lies in making available a method for the manufacture of gelatine-free shape bodies.
A further object lies in preparing a mixture containing a starch which by way of se
Brocker Erich
Engel Dieter
Menard Rico
Tomka Ivan
Meyer Jerald L.
Nath Gary M.
Nath & Associates PLLC
Nordmeyer Patricia L.
Peter Greither
LandOfFree
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