WO1999003754A1

WO1999003754A1 - Package for storing a product in a controlled atmosphere and method of making it

Info

Publication number: WO1999003754A1
Application number: PCT/GB1998/001869
Authority: WO
Inventors: Jeffrey Martin Davis
Original assignee: American Home Products Corp
Current assignee: Wyeth LLC
Priority date: 1997-07-15
Filing date: 1998-07-14
Publication date: 1999-01-28
Anticipated expiration: 2000-01-15
Also published as: GB9714738D0; AU8224198A

Abstract

A package is provided for storing a product in a controlled atmosphere. The package comprises a first pack layer (1) of relatively lower puncture resistance, a second pack layer (2) of gas/vapour permeable material and a third pack layer (3) of relatively higher puncture resistance wherein the second layer (2) is intercalated between the first (1) and third (3) layers such that the first (1) and second (2) layers define a first space (4) suitable for housing a product (5) and the second (2) and third (3) layers define a second space (6) suitable for housing an atmosphere-modifying material (7), such that any gas or vapour trapped in the package is able to pass between the first (4) and second (6) spaces but wherein the product (5) may be physically separated from the atmosphere-modifying material (7).

Description

PACKAGE FOR STORING A PRODUCT IN A CONTROLLED ATMOSPHERE AND METHOD OF MAKING IT

The present invention relates to a package and to a method for the manufacture thereof. The package is particularly well suited to storage of materials which need to 5 be kept in a controlled atmosphere environment, such as pharmaceutical products.

There are many materials which are sensitive to components of the air. For example, many pharmaceutical products are highly moisture-sensitive and/or are liable to oxidise in the presence of atmospheric oxygen. One example is the effervescent 10 tablet formulation. This usually contains an acid and a base which react in the presence of water. Moisture in the air can cause this reaction to take place prematurely, thus causing undesirable deterioration of the product prior to use. Other examples include products which are sensitive to oxygen.

15 FR-A-2660634 (Airsec Industries) discloses a packaging for pharmaceutical products comprising a half shell made from injected plastics material and having two chambers. One of the chambers contains a desiccant which is held in place by a semi- permeable membrane. The other chamber houses a pharmaceutical product and is connected to the first chamber by a passageway. Air passing through the passageway

20 and through the semi-permeable membrane is dried on contact with the desiccant and it is stated in the document that this maintains the air in the second chamber in a dry state and thus prevents deterioration of the pharmaceutical product. However, this construction is relatively cumbersome for many purposes and is expensive to produce.

25 WO 96/07601 (Ortho) discloses a blister package for moisture sensitive pharmaceutical preparations. However, the rigid moulded construction of this package is expensive and inconvenient with respect to manufacture and use. GB 2246107 (W R Grace), WO 88/01592 (Garwood) and WO 87/02965 (Garwood) all disclose modified atmosphere packs for storing food. Once again however, the manner of construction of these packages makes them expensive and inconvenient with respect to manufacture and use.

The present invention seeks to provide a package which is more convenient to manufacture, store and use than the packs previously known in the art.

According to the present invention there is provided a package for storing a product in a controlled atmosphere said package comprising a first pack layer of relatively lower puncture resistance, a second pack layer of gas/vapour permeable material and a third pack layer of relatively higher puncture resistance wherein the second layer is intercalated between the first and third layers such that the first and second layers define a first space suitable for housing a product and the second and third layers define a second space suitable for housing an atmosphere-modifying material, such that any gas or vapour trapped in the package is able to pass between the first and second spaces but wherein the product may be physically separated from the atmosphere-modifying material.

Preferably the first space is adapted to house a product in the form of a pharmaceutical preparation such as a tablet or powder.

Preferably the second space is adapted to house an atmosphere modifying material in the form of a desiccant such as silica gel powder. Preferably the first pack layer of lower puncture resistance is a multilayer laminate, preferably a paper/aluminium foil/polyethylene laminate.

Preferably the second pack layer of gas/vapour permeable material is a semi- permeable membrane formed, for example, from spun bonded polythene.

Preferably the third pack layer of relatively higher puncture resistance is a multilayer laminate, preferably a polyethylene terephthalate/aluminium foil/polyethylene laminate.

Preferably the package takes the form of a sachet. Preferably the first, second and third pack layers are substantially conterminous.

In one embodiment overlapping edges of the first, second and third pack layers are heat-sealed, and optionally crimped.

In a further embodiment an atmosphere-modifying material is contained within the interstices of the second pack layer of gas/vapour permeable material.

Suitably the package comprises a packaged product comprising an atmosphere sensitive product in the first space and an atmosphere modifying material in the second space. Suitably the atmosphere sensitive product is a water-sensitive pharmaceutical product such as an effervescent tablet and the atmosphere modifying material is a desiccant. Alternatively the atmosphere sensitive product may be an oxygen-sensitive pharmaceutical product and the atmosphere modifying material may be an oxygen-removing material such as iron filings. The present invention further provides a method for preparing a package as claimed in any one of the preceding claims by: a) combining strips of the first, second and third pack layers; b) introducing a product between the first and second layers and introducing an atmosphere modifying material between the second and third layers; and c) separating units of packaging from the combined strips.

Suitably the strips are combined by heat sealing along their long edges. Preferably they are combined by passage over rollers. Suitably the finished packages are separated by heat sealing and, if necessary, cutting the combined strips across their width.

In one embodiment all three of the strips are combined at substantially the same time. In an alternative embodiment two of the strips are combined in a first operation and the remaining strip is combined with the strips combined from the first operation as part of a second operation .

The present invention will be better understood with reference to the accompanying Drawings, in which:

Figure 1 is a cut-away (schematic) representation of a package in accordance with the present invention with the three layers cut away in turn to show the internal construction (the layers are in fact conterminous and of substantially the same size in this embodiment);

Figure 2 is a cross section (again in schematic form) through the package of Figure 1 along the line II-II of Figure 1 ; Figure 3 is a schematic representation of a first method of manufacture of the package of Figures 1 and 2; and

Figure 4 is a schematic representation of an alternative method of manufacture of the package of Figures 1 and 2.

With reference to Figures 1 and 2, the package comprises three substantially square, conterminous and mutually overlaid pack layers in the form of sheets (1,2,3). The first sheet (1) provides a barrier of relatively lower puncture resistance and is a multilayer laminate consisting of paper (on the external face which forms part of the outside of the package) aluminium foil (in the middle) and polyethylene (on the internal face). This first sheet is adjacent to and overlays a second pack layer of gas/vapour permeable material which provides a semi-permeable barrier in the form of a membrane (2) having a relatively high puncture resistance compared to the first sheet. The membrane is formed of spun bonded polythene of the type sold under the trade name "Tyvek 1073B" by the Du Pont Corporation. On the other side of the semi-permeable membrane lies a third pack layer (3) (again providing a barrier of relatively high puncture resistance compared to the first pack layer) in the form of a multilayer laminate consisting of polyethylene (on the internal face), aluminium foil (in the middle) and polyethyleneterephthalate (on the external face). Thus the second sheet (2) is intercalated between the first sheet (1) and the third sheet (3)

The three sheets are bonded together along their adjacent edges (8) to form a sachet by heat-sealing of the type well-known in the art. The heat-sealed area is crimped to ensure that the inside of the sachet is substantially sealed from the external atmosphere. It will be seen that the first sheet (1) and semi-permeable membrane (2) form a first space (4) suitable for housing a pharmaceutical product such as the effervescent tablet (5) shown. Likewise, the semi-permeable membrane (2) and the third sheet (3) form a second space (6) suitable for housing an atmosphere-modifying material such as the desiccant material (7) shown.

The semi-permeable membrane is substantially impervious to the pharmaceutical and desiccant materials housed in the internal spaces (4 and 6) but is permeable to air and water vapour. Any water vapour present in space (4) is free to pass through the semi-permeable membrane (2) where it is absorbed by the desiccant material (7). This ensures the maintenance of a substantially water vapour-free atmosphere in the said first space (4) thus ensuring that the pharmaceutical tablet housed therein is kept dry and prevented from deteriorating during storage.

To retrieve the product from the package the user simply punctures the first pack layer (1) (eg by tearing) and retrieves the product from the first space ready for use. The higher puncture resistance of the second and third pack sheets prevents the user from disturbing or releasing the atmosphere modifying material in the second space during this operation.

Figure 3 is a schematic illustration of apparatus suitable for manufacturing the package of Figures 1 and 2 above. It will be appreciated that this is based on generally conventional strip packaging equipment. The apparatus comprises two mutually opposing rollers (9 A, 9), over the first of which is suspended a tablet feeding device (10) and over the second of which is suspended a desiccant feeding device (11).

In use, a long strip (12) about 5cm wide (or as appropriate to the intended size of the pack) of the semi-permeable membrane material is fed continuously between the two rollers (9,9 A) to emerge along a line substantially tangential to both rollers. At the same time, a similar sized strip (13) about 5cm wide of the laminate material forming the barrier of lower puncture resistance making up the first barrier ( 1 ) of the package is fed over the first roller (9 A) such that the strip follows the circumference of the roller up to the point where the rollers meet and then continues parallel with and adjacent to the strip of semi-permeable material. In a similar way, a 5cm strip (14) of the laminate material forming the barrier of higher puncture resistance is fed over the second roller (9) to emerge from the roller parallel with and adjacent to the semi- permeable material, but on the opposite side to the lower puncture resistance strip (13).

The tablet feeding device (10) is operable to introduce individual tablets between the lower puncture resistance strip (13) and the semi-permeable strip (12) and the desiccant feeding device (11) is operable to introduce measured quantities of desiccant material between the semi-permeable strip (14) and the higher puncture resistance strip (14). The tablets are introduced at a rate of about one tablet per 5cm of strip length (corresponding to one tablet per finished package; although it will be appreciated that more than one tablet per package could be included if desired, and if so the rate of introduction would be correspondingly increased). The desiccant material (in the form of silica gel powder) is suitably introduced at a rate of about 0.1 g per 5cm of strip length although it will be appreciated that more or less can be introduced if desired (in which case the rate of introduction can be varied accordingly).

As the three strips pass between the two rollers (8,9) their long edges are heated to bond the strips together along their length. In another operation, the strips are bonded together by heat-sealing in a direction transverse to the direction of movement (ie across their widths) to seal individual sachets of about 5cm by 5cm. These are then separated by a cutting tool (not shown) to provide the final sealed sachets.

It will be appreciated that in practice there may be several (eg 4 to 6 or more) of the above types of lanes (collections of strips) running together in parallel over a common set of rollers.

Figure 4 shows a schematic representation of an alternative apparatus for manufacturing the package of Figures 1 and 2. This alternative apparatus has two sets of mutually opposing rollers (15, 16 and 17, 18). A desiccant feeding device (19) is positioned immediately above the meeting point of the first pair of rollers (15, 16) and a tablet feeding device (20) is positioned immediately above the meeting point of the second pair of rollers (17, 18).

In use, a long strip (21), about 5cm wide (or as appropriate to the intended size of the pack), of the Tyvek® semi-permeable material used for the semi-permeable barrier, is fed over the first roller (15). The strip follows a path around approximately a quarter of the circumference of the roller until it reaches the meeting point with roller (16) at which point the strip is fed off along a line substantially tangential to both of the said rollers. A similar strip (22), about 5cm wide (or again as appropriate to the intended size of the pack), of the laminate material used for the barrier of higher puncture resistance is fed in a similar way over the second roller (16) but in the converse direction.

As the two strips are fed between the rollers, the desiccant feeding device (19) introduces measured quantities of silica gel desiccant (eg approximately 0.1 g per 5 cm of strip length) between the strips. As the strips pass between the rollers they are heated from the laminate material side only (the Tyvek® material should not normally be heated directly) to bond the strips together along their length. In another operation, the strips are bound together by heat-sealing in a direction transverse to the direction of movement (ie across their widths) to seal individual sachets of about 5cm by 5cm (each sachet thereby containing eg about 0.1 g of desiccant material).

The bonded strips are then passed through the second set of rollers (17,18). The combined strips follow a path around approximately a quarter of the circumference of the first roller (17) until they reach the meeting point with roller (18) at which point the strips are fed off along a line substantially tangential to both of the said rollers. A similar strip, (23) about 5cm wide, of the laminate material used for the barrier of lower puncture resistance is fed in a similar way over the second roller (18) but in the converse direction.

As the strips are fed over the rollers the tablet feeding device (20) introduces individual tablets between the remaining strip (23) and the previously bonded strips which are the output from the first set of rollers. The tablets are suitably introduced at a rate of about one tablet per 5cm of strip length. In addition, as the strips pass between the rollers they are heated to bond the three strips together along their length. In another operation, the strips are bond together by heat-sealing in a direction transverse to the direction of movement (ie across their widths) to seal individual sachets of about 5cm by 5cm in a continuous strip (24). The seals from the second set of rollers are contrived to be coincident with the seals from the first set. These sachets are then separated by a cutting tool (not shown) to provide the final sealed sachets.

It will be appreciated that machinery used for the purpose of making strip packs sometimes uses reciprocating jaws instead of rollers, and such machinery may also be used to manufacture the packs of the present invention.

Claims

CLAIMS:

1. A package for storing a product in a controlled atmosphere said package comprising a first pack layer of relatively lower puncture resistance, a second pack layer of gas/vapour permeable material and a third pack layer of relatively higher puncture resistance wherein the second layer is intercalated between the first and third layers such that the first and second layers define a first space suitable for housing a product and the second and third layers define a second space suitable for housing an atmosphere-modifying material, such that any gas or vapour trapped in the package is able to pass between the first and second spaces but wherein the product may be physically separated from the atmosphere-modifying material.

2. A package as claimed in Claim 1 wherein the first space is adapted to house a product in the form of a pharmaceutical preparation.

3. A package as claimed in Claim 1 or Claim 2 wherein the second space is adapted to house an atmosphere modifying material in the form of a desiccant.

4. A package as claimed in any one of the preceding claims wherein the first pack layer of lower puncture resistance is a multilayer laminate.

5. A package as claimed in Claim 4 wherein the laminate is paper/aluminium foil/polyethylene.

6. A package as claimed in any one of the preceding claims wherein the second pack layer of gas/vapour permeable material is formed from spun bonded polythene.

7. A package as claimed in any one of the preceding claims wherein the third pack layer of relatively higher puncture resistance is a multilayer laminate.

8. A package as claimed in Claim 7 wherein the laminate is polyethylene terephthalate/aluminium foil/polyethylene .

9. A package as claimed in any one of the preceding claims which takes the form of a sachet.

10. A package as claimed in any one of the preceding claims wherein the first, second and third pack layers are substantially conterminous.

11. A package as claimed in any one of the preceding claims wherein the first, second and third pack layers are all flexible and non-rigid layers.

12. A package as claimed in any one of the preceding claims wherein overlapping edges of the first, second and third pack layers are heat-sealed, and optionally crimped.

13. A package as claimed in any one of the preceding claims wherein an atmosphere-modifying material is contained within the interstices of the second pack layer of gas/vapour permeable material.

14. A packaged product comprising a package as claimed in any one of the preceding claims which comprises an atmosphere sensitive product in the first internal space and an atmosphere modifying material in the second internal space.

15. A packaged product as claimed in claim 14 wherein the atmosphere sensitive product is a water-sensitive pharmaceutical product and the atmosphere modifying material is a desiccant.

16. A package as claimed in claim 14 wherein the atmosphere sensitive product is an oxygen-sensitive pharmaceutical product and the atmosphere modifying material is an oxygen-removing material such as iron filings.

17. A method for preparing a package as claimed in any one of the preceding claims by: a) combining strips of the first, second and third pack layers; b) introducing a product between the first and second layers and introducing an atmosphere modifying material between the second and third layers; and c) separating units of packaging from the combined strips.

18. A method as claimed in claim 17 wherein the strips are combined by heat sealing along their long edges.

19. A method as claimed in claim 17 or claim 18 wherein the strips are combined by passage over heated rollers.

20. A method as claimed in any one of claims 17 to 19 wherein the finished packages are separated by heat sealing and, if necessary, cutting the combined strips across their width.

21. A method as claimed in any one of claims 17 to 20 wherein all three of the strips are combined at substantially the same time.

22. A method as claimed in any one of claims 17 to 20 wherein two of the strips are combined in a first operation and the remaining strip is combined in a second operation with the strips combined from the first operation.