CA2595062A1

CA2595062A1 - Container for medical products and method of sealing thereof

Info

Publication number: CA2595062A1
Application number: CA002595062A
Authority: CA
Inventors: Andrew John Ede
Original assignee: Individual
Current assignee: Pfizer Ltd
Priority date: 2005-02-03
Filing date: 2006-01-27
Publication date: 2006-08-10
Also published as: GB0502252D0; EP1855959A1; JP2008528396A; WO2006082514A1

Abstract

A container for medical products and a method of sealing thereof wherein the container includes a base sheet having first and second' opposing faces, at least one pocket formed in the. first face for holding a medical product and a lid sheet having -inner and outer faces, the inner face being sealed to the first face wherein the base. and the lid sheet are formed from metal and are sealed' to one another with a weld between the metal.

Description

-~-CONTAINER FOR MEDICAL PRODUCTS

The present invention relates to a container.for medical products and a 5= method of sealing thereof. In particular, it relates to a container including a base having at least one pocket and a method of sealing a lid sheet.to the base.
The present application 'is particularly concerned with contaiiiers for storing moisture sensitive medicaments, such as dry powders for inhalation.
Furthermore, it is- based on a consideratioa of problems relating to containers useful for storing individual doses of inedicament. It is -known to create storage chambers using injection moulded plastics.

These are typ'ically used for reservoir type devices where the reservoir .
contains sufficient powder for multiple doses and a metering device can meter out the -correct quantity of powder for each dose. However, plastics typically used in -injection moulding have a finite water vapour transmission rate such that, where the medicament is sensitive to the effects of moisture, it will degrade -over its shelf life and its in-use life.
As an alternative, medicament may- be packaged in blister packs as individual pre-metered doses. The blister packs are constructed from. a laminate of a polymer and a metal, such as aluminium. The aluminium provides a fully impermeable layer which totally blocks the passage of water vapour.. However, where the aluminium lid sheet is bonde.d to the aluminium laminate base, there is still a small path for.water vapour.transmission along the sealing polymer layer. Although this layer may only be between 20 and 1.00 microns thick, it is still able to transmit sufficient moisture over loag periods of time to affect the medicament properties.
It is an object of the present inventioa to. at least reduce the problems discussed above and provide an.improved container. . = =
According to the present invention, there is provided a container for medical products including: . , a base having first and second opposing faces and at least one pocket formed in the first face for holding a medical product; and

-2-. .
a lid sheet having inner and outer faces, the inner face being sealed to the first.
face; wherein the base.and the lid sheet are formed from metal and are sealed to 'one another with a weld between the metal.

According to the present invention,. there is also provided a method of sealing a container for medical products, the container including a base having first and second opposing faces, at least one pocket formed in the first face for holding a medical product and a lid sheet having inner and outer faces, the.inner face being sealed to the first face, the base and the lid sheet being formed from metal, the method including:

welding the metal of the base to.the metal of the lid sheet. .
In this way, it is not necessary to provide any bonding material or polymer layer between-the metal of the lid sheet or the metal of the base. Hence, it is possible to avoid any moisture transmission at the point of sealing.
1.5 Previously, to minirnise the effects of moisture diffusion at the seal, the width of the sealing sectiori was increased so as to increase the length of diffusion path. Of course, this had the effect of increasing the size of the container and any device used to dispense medicament from it.
By virtue of the present invention, the size of the container may be reduced.
. The welding is preferably one of ultrasoaic welding, resistance welding, laser welding and electron beam welding or other welding technique.

It is also noted.that previously lid sheets and bases were joined together by using heat sealing. Jn particular, hot plates were used to press the foil laminates together so as to melt the sealing layer and bond the two films. Of course, this resulted in heating of the .medicament and could have adverse effects on the physical and chemical properties of the medicament.
By using ultrasonic welding at least, no such heating occurs.
It will be appreciated that the base can include only a single pocket for single dose containers or can include an array of pockets for multiple dose containers. The array can. take any suitable form and the base need not necessarily be planar.

-3- Preferably, the base includes a metal sheet having at least one.
depression formed in the first face so as to form said at least one pocket:
In other words, the base has the general form of known blister packs; but without any polymer on its first face. . .
The base could. be formed by pressing or cold. forming.
Preferably, the base is a lam'inate with a polymer covering the metal sheet on the second face.
In this way, the metal sheet is given further structural support and the polymer also protects the meta! from puncture. .
! 0. _ Preferably, the base includes a metal substrate having at ieast one through hole between said first and second faces and a base sheet sealing with said second .
face so as to form said at least one pocket: This provides an altemative to the more conventional form of blister pack and gives rise to a nuniber of advantages including steeper sided pockets allowing more, .15 efficient packing. . . Preferably, the sealing surface of the base sheet is metal and is sealed directly to the second face by welding.- .
In this way, the same advantages for the lid sheet are giveh to the base sheet ' and the pocket is extremely.well sealed. .
20 Preferably, the.lid sheet includes a metal :foil at at least the inner face:
Of course, 'the metal foil may have an -outer coating or coatings, for instance a lacquer, to facilitate any required printing.
Indeed, it is also possible for one or both of the first face and the inner face to have a thin lacquer coating. The welding process would'weld through the lacquer 25 and still provide 'metal to metal contact. Thus, at least one of the first face of the base and the inner face of the lid sheet may include (after the welding process) a thin lacquer in areas other than where the metal is welded..
At least one of the lid sheet and the basecan include a portion of metal surrounding the pocket and welded to the metal of the other of the lid sheet and the 30 *base.

4 PCT/IB2006/000235 ~_ ..

For instance,. a thin bead of metal or third foil could be sandwiched between the base and lid sheet effectively forming part of the base or lid sheet. =
Indeed, it is only necessary that the lid sheet be sealed to the base with metal to metal to contact.
A.ny form of insert could be used, provided this is.achieved, Preferably the metal is alumi.nium.
Preferably, the medical product is a. dry powder for inhalation.
The present invention is particularly important for containers of dry.powder, since such products are particularly susceptible to moisture.
The base can be welded to the lid sheet along a thin li.ne around the periphery.
of the at least. one pocket.

Alternatively, the base can be weided to the lid sheet over substantially all of the first face around the at least one pocket. ..
The particular position and area of sealing may be chosen according to the particular design of container in question.
The invention will be more clearly understood from the.following description, given by way of example only, with reference. to the accompany drawings, in which:
Figure.l illustrates a cross-section through a pocket according to the present invention;

.. Figure 2 illustrates a cross-section through an alternative pocket according to the present invention;
Figure 3 illustrates a variation of Figure 1;
Figure 4 illustrates a. variation of Figure 2; and Figure 5 illustrates schematically an apparatus seali.ng =a pocket according to the present invention. , The present invention relates. to an improved method for the joining of a metallic lid sheet to. base components of a containment system for medicinal products and to improved containers provided as a result.. It is particularly important for inhalatioa products in dry powder format and relates to the use of welding, particularly.ultrasonic welding, to join aluminium lid foils to aluminium base components.

. . -5- Ultrasonic welding works by the application of high frequency.mechanical energy to generate. vibrations and friction at the point ofjoining. For joining :
alumin.ium, the, two components are subjected to high pressure and mechanical vibration energy. This causes the two components to flow at a microscopic scale and.
to fuse together.

Figure 1 illustrates a cross-section through a pocket of a container according.
to the present invention..It 'will be appreciated that the container could include one or more pockets such as that illustrated.

The container includes a base component 10 formed from a laminate of 10 aluminium l 0a .and polymer l 0b.

The base component.10 has a first face 12 and a second face 14. It is formed by pressing qr cold forming so as-=to provide a depression 16 in the first face, thereby creating the pocket 18.
As will be seen, the polymer layer lOb is on the outside or second face.of the base, whereas the inside or first face is untreated aluminium I Oa or lacquered _ .aluminium where the lacqueri.ng is thin enough to enable welding through it.
A lid sheet 20 formed from a thin layer of aluminium has an inner face 22 and an outer face 24. As illustrated, the inner face 22, of the lid sheet 20 is sealed with the first face 12 of the base 10. Sealing is achieved by using welding, for instance ultrasonic, resistance, laser or electron beam welding, such that the aluminium l0a is bonded directly with the aluminium of the lid sheet 20. In this way, the pocket is surrounded entirely by metal.
It is to be noted that the outer face 24 of the lid sheet could be coated, for instance with a lacquer, so as .to facilitate printing.
Figure 2 illustrates an alternative embodiment.

As with Figure 1, only.one pocket is shown. However, the container could include a plurality of such pockets. The base 30 has a first face 32 and a second face 34. It is formed as a substrate from a relatively thick metal plate. The plate has formed in it a through hole 36 extending from the first face 32 to the second face 34 so as to provide the pocket 33 where medicament is stored.

As with the embodiment of Figure 1, a lid sheet 40 is provided having an inner face 42 and an outer face 44. The inner face 42 of the lid sheet 40 is sealed to the. first face 32 of the base 30 by welding. The lid is preferably a thin layer of aluminium, optionally coated. with a lacquer on the outside face 44 to facilitate .printing.
As can be:seen in Figure 2, the base.30 also includes a base sheet 46 having a ..
sealing surface 48 facing the second face 34. The'sealing surface 48 of the base sheet 46 is sealed with the second face 34 so as to form the pocket 38 with the through hole 46. The base sheer is also preferably formed ffom a metal, such as aluminium, and 10, sealed.by welding in the same way as the lid sheet 40. In this way, the pocket is surrounded entirely -by metal.
The outer surface of the base sheet 46 could of course be coated in a lacquer or similar..
It is also possible to coat the sealing surfaces with a thin lacquer before the ,.15 welding process. The metal is then welded,.through the lacquer. Figure 3.
illustrates a pocket like that of Figure 1 with coatings 17 and 21 and welds 11. Figure 4 illustrates a pocket like that of Figure 2 with coating 49 and welds 47.

'Figure 4 also illustrates another variation: 'It, is possible to provide a thin bead of metal or foil 28 between the lid sheet and the base. This can be considered as part 20 of the lid sheet or base .and welded to the lid sheet and base to form the desired metal to'metal contact. Figure 5 illustrates schematically an apparatus for sealing a lid sheet of a container such as illustrated in Figuie 1. This apparatus uses a preferred technique of ultrasonic welding.
25 A support 50 is provided for the base. With.a lid sheet in place, a press 60 is applied onto the lid sheet with a force so as to squeeze the lid sheet against the base.
An ultrasonic generator 70 then applies ultrasonic waves to the press 60 so as to form the ultrasonic weld between the lid sheet and the base. As illustrated, the press 60 contacts the lid sheet only as a thin line around the.

30 periphery of the pocket so as to form a corresponding seal. Howeverjt should be appreciated that alternative presses can be provided which form other seals.
For instance, the lid sheet could be pressed and. sealed at aU portions.where it contacts the base.
It should also be appreciated that presses can be provided which are suitable for sealing a plurality of pockets at once.
As mentioned above,. the apparatus of Figure 3 is highly schematic and it is possible to provide arrangements for containers of any desired shape or size and certainly for containers having the form of Figure 2.
By virtue of the present inveation, container can be fully hermetically sealed, since the. bond is metal-to-metal and there is ao thin layer of polymer or other .10 permeable substance to allow water to permeate. Because the seal is so effective,.its performance is not significantly dependent on its width. It is therefore possible to substantially reduce the width of the seal and hence the overall size of the product without compromising the integrity. of the seal.
Finally, because the welding process does not involve significant heat 15 generation, there is no risk of thermal damage to the medicament, eg.
powder for inhalation. :

Claims

1. A container for medical products including:
a base having first and second opposing faces and at least one pocket formed in the first face for holding a medical product; and a lid sheet having inner and outer faces, the inner face being sealed to the first face; wherein the base and the lid sheet are formed from metal and are sealed to one another with a weld between the metal.

2. A container according to claim 1 wherein the base includes a metal sheet having at least one depression formed in the first face so as to form said at least one pocket.

3. A container according to claim 2 wherein the base is a laminate with a polymer covering the metal sheet on the second face.

4. A container according to claim 1 wherein the base includes a metal substrate having at least one through hole between said first and second faces and a base sheet sealing with said second face so as to form said at least one pocket.

5. A container according to claim 4 wherein the sealing surface of said base sheet is metal and is sealed directly to said second face by welding.

6. A container according to any preceding, claim wherein the lid sheet includes a metal foil at at least the inner face.

7. A container according to any preceding claim wherein at least one of the first face of the base and the inner face of the lid sheet includes a thin lacquer in areas other than where the metal is welded.

8. A container according to any preceding claim wherein at least one of the lid sheet and the base includes a portion of metal surrounding the pocket and welded to the metal of the other of the lid sheet and the base.

9. A container according to any preceding claim wherein the metal is aluminium.

10. A container according to any preceding claim wherein the medical product is a dry powder for inhalation.

11. A container according to any preceding claim wherein said base is welded to said lid sheet along a thin line around the periphery of said at least one pocket.

12. A container according to any one of claims 1 to 10F wherein said base is welded to said lid sheet over substantially all of said first face around said at least one pocket.

13. A method of sealing a container according to any one of claims 1 to 10, the method including:
welding -the base to lid sheet.

_ 14. A method of sealing a container for medical products, the container including a base having first and second opposing faces, at least one pocket formed in the first face for holding a medical product and a lid sheet having inner and outer faces., the inner face being sealed to the first face, the base and the lid sheet being formed from metal, the method including:
welding the metal of the base to the metal of the lid sheet.

15. A method according to claim 13 or 14 further including:
welding said base to said lid sheet along a thin line around the periphery of said at least one pocket.

16. A method according to claim 11 or 12 further including:
welding said base to said lid sheet over substantially all of said first face around said at least one pocket.

17. A method according to any one of claims 13 to 1.6 wherein the step of welding includes one of:
ultrasonic welding;
resistance welding;
laser welding; and electron beam welding

18. A container for medical products constructed and arranged substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.

19. A method of sealing a container for medical products substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.