The invention relates to a method for packing coated containers, in particular reagent-treated test tubes for analytical determination, especially test tubes for immunological assay methods using immobilised reactants of such assay methods, and a packaging unit containing a large number of test tubes of the stated type.

Immunological assay methods frequently employ test tubes which have on their walls, in immobilised form, some substance (reactant) which is important for carrying out the assay method successfully, for example immobilised antibodies, immobilised antigens and specific im unoglobulins or other protein materials, and which are usually present in a protective matrix of an auxiliary substance forming a film on the walls of the test tubes (coated tubes) . After their production,

such test tubes must be packed in such a way that the frequently sensitive immobilised reactants retain their activity over as long periods as possible and reliable results can be obtained when the test tubes are used. This usually necessitates packing which guarantees reliable protection from moisture, dust and other contaminants. At present, such test tubes are usually packed by a procedure in which they are transferred from the trays into packaging containers, such as cartons or bags, to which bags containing a drying agent (silica gel bags) must be added in the case of sensitive substances or in the case of particular quality requirements, in order to regulate the moisture content in the pack. Such packagings have, inter alia, the disadvantage that, when a pack containing a large number of such test tubes is opened, the tubes are exposed to the effect of the surrounding atmosphere, which may result in test tubes which are not immediately used relatively rapidly becoming useless after the pack has been opened. In order to avoid this, in such packs all test tubes would additionally have to be individually sealed, entailing an additional packaging cost.

It is the object of the present invention to provide a method leading to a novel packaging unit, for packing containers coated with sensitive or optionally also volatile substances, such as test tubes for analytical methods, in particular immunological assay methods, which method permits rapid and safe automated packing of such containers or test tubes and ensures reliable protection of the tubes from moisture, dust and contamination of the individual unused tubes even after the total pack has been opened.

This object is achieved by a method and a packaging unit according to the Claims.

In the method according to the invention, the tubes coated with the intended reactants in a conventional manner known per se are provided, in the trays, with a common label which simultaneously seals the openings of a whole group of test tubes. Since the test tubes are usually arranged in the conventional trays in such a way that their openings are located in a plane, the label can be applied mechanically in a simple manner to the entire group of test tubes and, in that it adheres firmly to the edges of the openings of all test tubes, it firmly seals each individual test tube. The test tubes which are empty apart from the coating on their walls and are therefore light can, while adhering to the adhesive side of the label, readily be transferred to a container, which may be effected mechanically, for example with the aid of a suction device acting on the outside of the label.

The label is chosen so that it has a central area which corresponds approximately to the total base area of the group of test tubes and additionally has an edge which projects. When the group of test tubes adhering to the label is transferred to the container, the edge of the label projects laterally beyond the edge of a standard container open at the top, and the container as a whole is tightly sealed by the label by pressing this projecting edge against the upper edge of the outer side walls of the container.

Consequently, the packaging unit obtained in this manner has, on the one hand, an outer container which

is sealed in a dust-tight and moisture-tight manner and within which the individual tubes are further sealed individually and reliably owing to the adhesive bonding of the edges of their openings to the lower side of the covering label.

To remove the tubes, the label can be peeled off to such an extent that the number of test tubes which are required is exposed. However, it is preferable to use a container which permits separation of the upper edge region of its side walls which is adhesively bonded to the label, by virtue of the fact that, preferably, a thread running all around or a line running all around is incorporated in the container walls, which thread or line permits the container wall to be torn open and the upper wall region of the container to be separated in a known manner. Instead of a thread or a line, it is also possible to use other means known from the packaging industry for opening container walls or for separating container parts, for example perforations, score lines or marks for cutting along a corresponding line. In such a case, opening of the packaging unit and removal of individual or all tubes are effected in such a way that the pack is arranged with the label at the bottom, the container edge stuck to the label is separated from the remainder of the container and this remainder of the container is raised. A group of test tubes standing on their openings and still stuck to the label via these openings is obtained. The desired number of test tubes can now be detached from the label without impairing the seal of the other test tubes.

^• When the pressure-sensitive adhesive used for the label is suitably chosen, it is even possible to replace an erroneously removed test tube on the back of the label,

which retains its adhesiveness, and thus to seal said test tube.

If only individual test tubes have been removed and it is desired to restore the packaging unit for further use of the remaining test tubes, the removed lower part of the container can simply be inverted over the remaining test tubes and the packaging unit turned over and stored. At this stage, the side wall which has been torn open can of course be stuck by means of a self-adhesive tape. However, this is usually not necessary since the individual test tubes continue to stick to the label and are thus sealed.

The packaging unit according to the invention furthermore has the advantage that, owing to the direct binding of the individual test tubes to a label, the assignment of the test tubes is also unambiguous since the label usually has on its outside all information required for identifying the test tubes.

A preferably used container is a folding carton which, on the one hand, can be kept ready in a compact manner prior to packing and, on the other hand, can be pressed flat after the contents of the pack have been used and can be disposed of with the waste paper.

Although the present invention is described with respect to test tubes for immunological assay methods and moreover with reference to a preferred embodiment, it is however clear that, regarding both the container

.shape and the container material, many modifications are possible without departing from the scope of the present invention as a result. It is also possible,

for example, to provide circular outer containers or plastic containers with a label in the manner described. It is furthermore possible to bond the label adhesively to the edge of the container in some other way, for example with a flange-like edge or in such a way that it adheres to the inside of a projecting edge, even though such embodiments currently appear to be rather disadvantageous.

Since the bond between the container edge and the outer edge of the label should be as impermeable as possible and also permanent, it is of course possible for the container edge to be bonded adhesively to the label in turn to be provided with a pressure-sensitive adhesive or an adhesive. In the case of plastic containers, welding is in principle also possible in this region.

Regarding the adhesion of the test tubes to the inside of the label, it is preferable if the adhesive coating is such that the adhesiveness is permanently retained, so that accidentally removed tubes can be adhesively bonded again to the label, but it is also possible to use an adhesive which permits the edges of the test tubes to be adhesively bonded to the label only once, which may be advantageous, for example, when it is intended to permit a check to be carried out to determine whether the tube is the originally sealed tube or a tube which has already been removed and may have been handled.

In principle, it is also possible to provide the label

^' with scores, allowing individual rows of test tubes or individual test tubes to be torn off. In the case of all these embodiments, as long as use is made of the

advantages of the simultaneous adhesive bonding of a group of test tubes to a single label and the use of this label for sealing a container holding the entire group of test tubes, such embodiments are also covered by the present invention.

Finally, it should also be pointed out that the present invention was developed in particular for packing coated tubes for immunological assay methods and has particular advantages over the relevant prior art in this area, but that it is entirely possible to use the method according to the invention also in other areas. For example, the test tubes can also be coated with other reagents, for example indicators or catalysts, which are used in other areas of organic chemical or inorganic chemical analysis or for environmental test purposes or which also serve for carrying out specific reactions.

Finally, it is also entirely possible to use the method according to the invention in food technology, for example by selling containers coated with specific sensitive or volatile flavours in a pack of the type according to the invention, for example containers in which foods or luxury articles, such as flavouring additives, spice solutions, beverages or the like, are prepared by adding further components, for example liquids.

The present invention is illustrated in more detail below with reference to three Figures and to a preferred embodiment.

Fig. 1 shows a packaging unit according to the

invention, having a wall which has been partly broken away; Fig. 2a and 2b show embodiments of the adhesive label having differently shaped corners and Fig. 3 shows a cardboard folding carton suitable as a preferred outer container.

In the Figures, 1 designates a test tube having an upper edge 2 which, in the method according to the invention, is adhesively bonded to the adhesive side of a label 3 with production of the packaging unit according to the invention. The label 3 has a central area 4, which corresponds in its shape to the contour of the container 6 for the test tubes, and an edge region or edge 5 which can be adhesively bonded to the outside of the container 6 in such a way that, after adhesive bonding of the label to the edges of the test tubes and transfer of the entire group of test tubes with the label into and onto the container 6, the projecting edge 6 is bent downward and is adhesively bonded to the outside of the container 6.

The edge 5 of the label is preferably designed so that, on the one hand, bending of this edge is possible without tearing or creasing of the label and, on the other hand, secure sealing of the entire packaging unit is ensured also in the corner region of the container. This can be achieved by providing the edge with suitable incisions in the region of the corners. Figures 2a and 2b show suitable label shapes by way of example. It should be pointed out that the incisions .do not extend as far as the outer contour of the container. Owing to a certain internal elasticity/ plasticity of the paper material used for the labels,

secure adhesive bonding of the entire pack is easily possible in the cases described.

The preferred embodiment of the container shown in Fig. 3 is a so-called "ideal folding carton" which has been adapted to the present invention by incorporating a tear thread 8 which permits separation of the upper edge of the pack. The material of the folding carton is chosen so that the required protection for the intended contents is ensured. For example, a cardboard which inhibits moisture and/or gas exchange with the environment as a result of an additional coating may be used for this purpose, or said cardboard may furthermore have been provided with a cushioning inner layer.

The suitability of the packaging unit according to the invention for test tubes for immunological assay methods was tested by packing test tubes which were coated with immobilised antibodies against thyroid peroxidase (anti-TPO) on the one hand in a conventional manner by enclosing them in bags with the addition of a sachet containing a drying agent and, on the other hand, by the method according to the invention.

The results are shown in Table 1 below. In this Table, B ₀ /T represents "total binding/total activity", 50% IC represents "50% intercept" and CV represents

"coefficient of variance". A person skilled in the art can derive the reactivity or the shelf life of the test tubes from the values stated. It should be noted that

.the method according to the invention does not lead to a poorer shelf life. However, compared with the conventional method, it has, for the producer, the

advantages of more rapid processing and simple automation while ensuring at least an equivalent protection of the tubes from moisture, dust and contamination, and, for the user, the advantages of easy handling owing to the tear line on the folding carton. The individual tubes can be conveniently removed without impairing the seal of the other tubes, and remaining tubes can be conveniently replaced in the lower part of the container and, owing to their firm bond to the label, always remain reliably identifiable. If too many tubes are removed, these too can be resealed with the label without difficulties.

Table 1

n 34