Description

The invention relates to an improved capsule for substances to be mixed at moment of use.

For packaging substances to be mixed at moment of use, in particular for inserting an active substance internally of a solvent such as to obtain a solution immediately prior to use of the solution, packages have been known for some time which are single-dose or multiple-dose and which comprise a container containing the solvent (generally a liquid), on which a closing capsule is mounted, of various types, normally made of a plastic material. Closing capsules are known which internally exhibit a reservoir which is realised in two parts that are slidable with respect to one another; the external part is provided with a breakable bottom; the internal part (cutter) slides internally; the cutter exhibits a cutting element which, following a pressure exerted thereon, causes breakage of the breakable bottom. In the reservoir, and in particular in the internal cavity of the cutter, an active substance is contained which is usually in powder or granule form, and which on breakage of the breakable bottom of the external part of the reservoir falls into the container and dissolves in the liquid contained in the container.

The substances contained in the cutter, which are soluble in the liquid contained in the container and which are dissolved in the liquid at moment of use, are generally sensitive to moisture both for problems of a physical nature (they can cluster in an undesired way) and for problems of a chemical nature (their properties can be modified); the latter is very frequently the reason for which these preparations include the injection of the active substance into the solvent only at moment of use. This phenomenon is of particular significance in relation to the possible transmigration of moisture internally of the container, which as mentioned contains a liquid, internally of the reservoir containing the active substance. The materials the reservoirs containing the active substance are made of are, by their nature, permeable to moisture, even though to a small degree; this permeability leads to some consequences in the thickest zones of the reservoirs, although the time required for migration of the moisture in these zones is quite long. This phenomenon however becomes considerably significant both at the sliding surfaces between the two parts that make up the reservoir, and in proximity of the circumferential line of the breakable bottom of the internal part of the reservoir along which the cut is performed, as the thickness of this line is very small and the migration time required for the moisture to pass through this line is much shorter.

This phenomenon can lead to deterioration in relatively short times of the chemical-physical characteristics of the active substance contained in the reservoir, or at least part thereof. In particular, contact with even modest quantities of moisture causes the clustering of particles of product which make its subsequent dissolving in the solvent problematic, which negatively influences correct mixing of the solution. This problem assumes greater significance the smaller the particles of the product and the greater the hygroscopic quality of the product.

To obviate this drawback, an attempt has been made, in constructing the reservoirs, to use plastic materials having lower permeability to moisture. Apart from the fact that this solution does not eliminate but only slows the problem down, these materials have characteristics which make cutting thereof very difficult using cutters that are normally usable; their use is therefore particularly inconvenient.

A further solution adopted is to cover the breakable bottom of the reservoir with a multi-layer material, containing at least a layer of aluminium and a layer of plastic material; this solution provides a sure barrier to moisture in the bottom zone of the reservoir but does not prevent moisture from entering through the lateral surface of the reservoir in which the cutter slides, which is directly inserted into the container.

A further solution is to stick a multi-layer material containing aluminium and plastic on the mouth of the container, after having inserted the solvent internally of the container itself. Apart from the fact that it is difficult to glue the multi-layer material on a surface which might be made damp by the prior filling operation of the container, this solution involves the use of packaging machines for gluing the material to the container mouth which are considerably slower with respect to the usual machines, which simply insert a closing capsule onto the container mouth containing the solvent. The aim of the present invention is to obviate the drawbacks by providing a capsule which enables elimination of the drawbacks in the prior art, which is easy and economical to realise and use, and which enables conserving the products contained in the capsule from moisture for very long time periods.

An advantage of the present invention is to disclose a capsule which enables obtaining packages which are realisable by means of simple processes and machines, which are rapid and well tried and tested.

Further characteristics and advantages of the present invention will more fully emerge from the detailed description of various embodiments of the package in object, illustrated by way of non-limiting example in the figures of the drawings, in which:

figure 1 is an exploded view, in large scale and with some parts sectioned, of a possible embodiment of the reservoir of the capsule of the invention;

figure 2 is a vertical elevation view, with some parts sectioned, of the reservoir of the capsule of the invention, inserted on the mouth of the container;

figure 3 is a view in vertical elevation, with some parts sections, of the capsule of the invention inserted on the mouth of the container;

figure 4 is a vertical elevation view, with some parts sectioned, of the reservoir of the capsule of the invention cut and extracted from the mouth of the container.

The capsule 4 of the invention is used to contain hygroscopic substances which have to be mixed with a solvent at moment of use; this type of capsule is used in particular for obtaining single-dose packages of medicines or the like.

The capsule of the invention is applied to a container 1, normally a glass bulb or a vial, which is provided with an open mouth 2 and which contains a solvent. For use, the container is closed by the capsule in which an active substance 3 is inserted.

The capsule 4 is of the type comprising a reservoir 5, in which the active substance 3 is inserted, realised by assembly of various elements which will be described in the following. The reservoir is provided with a breakable bottom 5a and internally of which a cutter element 6 is provided which on command is destined to break the breakable bottom 5 a. The capsule further comprises a closing cap 10 destined to cover the whole reservoir 5, when the reservoir 5 is inserted in the mouth of the container. Like known capsules of this type, the capsule of the invention is realised, apart from those parts which are differently specified, of a plastic material. The reservoir 5 of the capsule of the invention comprises a tubular connector 7, which is provided with a first zone 7a internally of which the cutter 6 is inserted and can sealedly slide; the tubular connector further comprises a second zone 7b, which is concentric to the first zone 7a and has a greater diameter with respect thereto.

The reservoir 5 of the capsule of the invention further comprises a hollow cap 8 which exhibits a first end 8a that is closed by the breakable bottom 5a and which is conformed such as to solidly and sealedly insert internally of the second zone 7b of the tubular connector 7. The hollow cap 8 further exhibits a second end 8b which is open and is conformed such as to insert solidly and sealedly internally of the container 1 mouth 2; for this purpose, a ring can for example be provided externally of the end 8a, which ring joints in a corresponding channel provided internally of the zone 7b.

The internal diameter of the hollow cap 8, which is preferably constant, is not smaller than the internal diameter of the first zone 7a of the tubular connection 7; the diameter is preferably kept, for reasons which will more fully emerge herein below, slightly greater than the internal diameter of the first zone 7a.

A projecting ring 8c is provided externally of the hollow cap 8, which ring 8c abuts on the end 7b of the tubular connection 7 when the hollow cap 8 inserts in the second zone 7b of the tubular connector 7; in order for the breakable bottom 5a present on the first end 8a of the hollow cap 8 to go to rest on the circular crown defined by the difference of the diameters between the zones 7a and 7b of the connector 7 when the cap 8 inserts in the tubular connector 7, the axial distance of the ring 8c from the first end 8a of the hollow cap 8 is equal to the internal axial depth of the second zone 7b of the tubular connector 7. Further, when the hollow cap 8 inserts in the mouth 2 of the connector 1 , the ring 8c goes to strike on the external wall of the mouth 2 of the container 1 such as to halt the penetration of the cap 8 internally of the container 1.

The capsule 5 further comprises a disc 9 which is made of material containing at least a layer of aluminium and which is solidly connected externally to the first end 8a of the cap 8 such as to cover it completely; the disc 9 is preferably realised with a multilayer material, of known type, which comprises at least a layer of aluminium and a layer of plastic material; the connection of the disc 9 to the first end 8a of the hollow cap 8 is thus obtained by heat-welding of the layer of plastic material on the end 8a of the cap 8. Naturally other types of connection can be used, such as for example gluing.

Summing up, the capsule of the invention comprises a closing cap, which can be of any type, and a reservoir which is realised as a group of elements made up of the cutter 6, the tubular connector 7, and the hollow cap 8 on which the disc 9 is connected; the active substance is contained internally of this reservoir.

The mouth 2 of the container 1 is provided, as is quite usual for these containers, with an external thread. The maximum external diameter of the reservoir 5 is made slightly smaller than the external diameter of the mouth 2 such that the closing cap 10, also provided with an internal thread, can couple by screwing on the mouth of the container. The cap 10 of the capsule of the invention, in one of its possible embodiments, comprises internal tabs 10a which develop along the internal generatrices thereof and which abut on the ring 8c when the closing cap 10 is inserted on the mouth of the container. However, closing caps of different shape and mode of use can be used. For example a closing cap of known type can be used which presses on the cutter, screwing onto the neck of the container, and which remains solidly connected to the reservoir and is extracted together therewith in order to open the container.

To pack the capsule, first the reservoir is filled and assembled.

The first end 8a of the hollow cap 8, on which the disc 9 has been previously connected, is inserted into the second zone 7b and solidly connected there. The active substance is normally placed internally of the cutter which is then inserted into the first zone 7a of the tubular connector 7 to which the cap 8 has been connected (or, frequently, it is the tubular connector which is inserted into the cutter filled with active substance); the depth of insertion of the cutter in the connector is determined automatically by the packaging machines such that the cutting edge of the cutter does not reach the separation surface existing between the first and the second connector zone.

At this point the reservoir, thus packed, can be connected to the container, first filled with solvent, by inserting the second end 8b of the cap 8 in the mouth 2 of the container 1. This operation is very simple and can be performed using the normal fast packaging machines as the end 8b of the cap 8 is the same as the ends of the usual and known types of reservoirs used up to now; this is obviously not possible in the solutions which include a "moisture barrier" glued on the mouth of the container.

A further notable advantage of the capsule of the invention is that it has a secure "moisture barrier" represented by the disc 9 which covers and protects both the breakable bottom and the sliding zone between the cutting edge and the internal walls of the reservoir from moisture infiltrations, a thing that is not possible with normal capsules having the "moisture barrier" arranged on the bottom of the capsule. Further, with the capsule of the invention, possible lacerations of the barrier element during packaging are prevented, as the element is inserted internally of the capsule, in a protected zone, and its edges are squeezed between two surfaces which prevent any deterioration thereof.

Finally, it is to be noted that the fact that the sliding surfaces of the cutting edge are protected from the "moisture barrier" means that known materials can be used which facilitate the sliding action, and which cannot be used in many of the solutions; the sliding between the ring and the cutter is in fact improved with respect to existing solutions because a coupling can be used between cylindrical surfaces that is longer than normal couplings between these surfaces and can be realised with more rigid materials having a better barrier effect.

Once the reservoir has been inserted on the container neck, the package is completed by inserting the closing coupling 10 on the capsule, which, as with known applications, is advantageously provided with a security strip guaranteeing the package integrity; both during the packaging stage and after, the presence of the tabs 10a prevents the cover 10 from inadvertently pressing on the cutter 6 and causing undesired laceration of the disc 9 and the breakable bottom 5a.

The user uses the capsule of the invention as normal capsules at present available. Once the cap 10 has been unscrewed, causing the fracturing of the security ring, a pressure is placed on the cutter 6 which causes laceration of the disc 9 and the breakable bottom 5 a with a consequent falling of the active substance internally of the container; the capsule is then extracted from the container neck and the solution therein contained can be used.