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(11) EP 2 801 475 A1

(12) EUROPEAN PATENT APPLICATION

(43) Date of publication: (51) Int Cl.: 12.11.2014 Bulletin 2014/46 B32B 15/08 (2006.01) B32B 15/20 (2006.01) B32B 27/30 (2006.01) B32B 27/32 (2006.01) (2006.01) (2006.01) (21) Application number: 13166620.8 B32B 27/36 B32B 1/02 B32B 3/28 (2006.01) (22) Date of filing: 06.05.2013

(84) Designated Contracting States: (72) Inventor: Depla, Anouschka AL AT BE BG CH CY CZ DE DK EE ES FI FR GB 2640 Mortsel (BE) GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR (74) Representative: Viaene, Kris Designated Extension States: Agfa-Gevaert N.V. BA ME IP Department 3622 Septestraat 27 (71) Applicant: AGFA-GEVAERT 2640 Mortsel (BE) 2640 Mortsel (BE)

(54) Novel blister pack for pharmaceuticals

(57) A novel transparent blister pack for pharmaceu- transparent barrier film. The novel transparent blister has ticals is disclosed wherein the blister is made from an superior barrier properties. The novel transparent blister aluminium based laminate and the lidding foil from a can be made completely halogen free. EP 2 801 475 A1

Printed by Jouve, 75001 PARIS (FR) 1 EP 2 801 475 A1 2

Description present invention.

FIELD OF THE INVENTION FIGURE 2 shows a schematic representation of an embodiment of a process to prepare a blister pack [0001] The present invention relates to a novel blister 5 according to the present invention. pack for pharmaceuticals. DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION [0011] A blister pack according to the present invention [0002] A "blister pack" covers several types of pre-10 comprises a cavity forming foil (1) an a lidding foil (2) formed packaging used for consumer goods, food characterized in that the cavity forming foil comprises and pharmaceuticals. The primary component of a blister an aluminium-based laminate film and the lidding foil is pack is a cavity, often referred to as "pocket" or "blister", a transparent barrier film. holding the product. The blisters holding the product are then sealed by a lidding foil. 15 Transparent barrier film [0003] When used for pharmaceuticals, blister packs are designed to protect the product from the environment [0012] The lidding foil of the blister pack according to (moisture, O2, light) to guarantee physical and chemical the present invention is a transparent barrier film. stability of the product. The type of material used to pre- [0013] The barrier film has preferably a Total Light pare the blister pack determines its "barrier" properties 20 Transmission (TLT), measured according to ASTM against water vapour, oxygen, light, etc. D1300, of at least 75 %, more preferably of at least 80 [0004] Ablister pack with thehighest protection against %, most preferably of at least 85 %. the environment has a lidding foil and a blister both based [0014] The barrier film comprises of a substrate (22) on aluminium. A major disadvantage of such a so-called and optional barrier layers (21) provided thereon. In one cold formed blister pack is the lack of transparency. 25 embodiment of the lidding foil, the substrate, or a layer [0005] Most blister packs however have an aluminium on the substrate, is adjacent to the pharmaceutical while based lidding foil and a transparent blister. Such a so- a barrier layer is the outer layer. In another embodiment called thermoformed blister is obtained by of the lidding foil, a barrier layer, or a layer on the a barrier a flat, transparent . Such a blister has the ad- layer, is adjacent to the pharmaceutical while the sub- vantage of transparency. However, given the fact that a 30 strate is the outer layer. transparent plastic film has to be thermoformed to form the blister limits the choice of transparent polymer films Substrate that can be used for that purpose. For that reason barrier films having superior barrier properties, for example [0015] The substrate may be a polyvinylchloride (PVC) those based on composite materials, or certain halogen 35 substrate, or a substrate based on copolymers made of free plastic films, such as for example biaxially oriented vinyl chloride units and of one or more other monomers films, are not suitable to form a transparent (VC copolymers). PVC is the most widely used substrate blister. in blister packs. The main advantages of PVC are its low cost price and its very good processability. The main dis- SUMMARY OF THE INVENTION 40 advantages are its poor barrier properties and a negative environmental connotation due to its chlorine content. [0006] It is an object of the present invention to provide [0016] The substrate is preferably a halogen free pol- a transparent blister pack having superior barrier prop- ymeric film. Preferred halogen free polymeric films are erties. made from ,polyolefins, , polyacry- [0007] It is another object of the present invention to 45 lonitrile, or copolymers made of acrylonitrile units and provide a halogen free, transparent blister pack. one or more other monomers. [0008] Both objects are realized by the blister pack as [0017] Thepolyester ispreferably polyethylenetereph- defined in claim 1. thalate (PET) or copolymers made of ethylene tereph- [0009] Further objects of the invention will become ap- thalate units and one or more other monomers. The PET parent from the description hereinafter and the depend- 50 may be amorphous (APET) or crystalline. The latter can ent claims. be used in the blister pack of the present invention be- cause it the substrate does not have to be thermoform- BRIEF DESCRIPTION OF THE DRAWING able. Such a crystalline PET may be for example biaxially oriented PET (BOPET). Another preferred polyester is [0010] 55 PETG, a polyester copolymer composed of ethylene terephthalate units and cyclohexanedimethanol units. FIGURE 1 shows a schematic representation of an [0018] Preferred polyolefins are (PP), embodiment of a blister pack according to the (PE), cyclo-olefin copolymers (COCs), and

2 3 EP 2 801 475 A1 4 cyclo-olefin polymers (COP). single pass. [0019] Substrates based on may also [0029] In that preferred method a single layer of at least be used in view of their biodegradability. Polyethylene- 20 g/m2 of PVDC latex is coated on a substrate and dried furanoate (PEF) substrates may also be of interest as at a dry temperature (Td) of at least the film formation 5 they are 100 % biobased and recyclable. temperature (Tf) of the PVDC latex at a relative humidity [0020] The thickness of the substrate is preferably be- (RH) according to the following formula: tween 10 and 1000 mm, more preferably between 50 and 500 mm, most preferably between 190 and 350 mm. [0021] The substrate may be surface treated, typically to enhance the adhesion between the substrate and lay- 10 ers provided thereon. [0022] Examples of such a surface treatment include [0030] PCTFE based films are laminated on a sub- a corona discharge treatment, a flame treatment, a UV strate. PCTFE films are prepared by polymerization of treatment, a low pressure plasma treatment, and an at- chlorotrifluoroethylene (CTFE). Again, the thickness of mospheric plasma treatment. A preferred surface treat- 15 the PCTFE film determines the barrier properties. They ment is a corona discharge treatment. have higher barrier properties, especially against mois- ture, compared with PVDC based films. Commerically Barrier layers available PCTFE films are for example the ACLAR® films from Honeywell. [0023] To further improve the barrier properties of the 20 [0031] When using PCTFE films as blister forming foils, transparent lidding foil, one or more barrier layers may the thickness of the PCTFE, and as a consequence its be provided on the substrate. barrier properties, are limited because the flexbility of [0024] These layers may be provided on the substrate such thick PCTFE becomes insufficient to (thermo) form by laminating one or more barrier films or sheets on the the blisters. The thickness of PCTFE films is typically substrate, by one or more barrier coating on the 25 between 15 and 152 mm. PCTFE films having a thickness substrate, by coextrusion of two or more barrier layersor, of more than 50 mm already have an insufficient flexibility or by any other technique. to form blisters. The flexibility of "thick" PCTFE films can [0025] Widely used barrier layers are based on halo- be improved by a PE layer of 20 - 50 mm located between gen containing polymers such as the support and the PCTFE film. In a blister pack accord- (PVDC) or polychlorotrifluoro ethylene (PCTFE). 30 ing to the present invention, because the PCTFE film is [0026] PVDC is a vinylidene polymer selected from the now used as (flat) lidding foil, the limited flexibility of thick group consisting of polyvinylidene chloride and copoly- PCTFE films are no longer an issue. Therefore, blister mers made of vinylidene chloride units and other mono- packs with superior barrier properties while maintaining mers (VCD copolymers). A preferred PVDC is a vinyli- the advantage of transparancy are feasable. dene chloride - methyl acrylate copolymer. 35 [0032] The flexilibity issue of thick barrier films when PVDC is typically coated from aqueous latex dispersions. used as blister forming foils is not only a problem for Such latex dispersions are commercially available, for PCTFE films, but also for other barrier films. example from Solvay (Diofan® A736, Diofan® [0033] PCTFEbased filmsmay be combined with other 193Dand Diofan®Super B), from Asahi Kasei Chemicals films to further improve the barrier properties. For exam- (L801, L803, L803C, L817B), and from Dow Chemical 40 ple the commercially available ACLAR®/BAREX® lami- (Serfene® 195). nate may be provided on the substrate, resulting in very A PVDC based barrier coating has the advantage that it good barrier properties against both moisture and oxy- exhibits good barrier properties not only with respect to gen. BAREX® films contain resins which are produced oxygen but also with respect to water vapor. by copolymerization of acrylonitrile and methyl acrylate [0027] The dryweight of a PVDC coating on a substrate 45 in a 75:25 ratio onto a nitrile rubber backbone. is usually from 40 up to 180 g/m2 PVDC, depending on The BAREX® film component for such laminates is avail- the barrier properties strived for. Such PVDC able from Klockner Pentaplast America, Plastiques Ven- are typically coated from aqueous latex dispersions and thenat, and Innovative/Greenway Plastics. To improve dried at high temperatures (70-130°C) and low relative the adhesion between both components, an humidities (RH < 5%). Under such drying conditions, the 50 may be used. maximum dry coating weight in one single pass is limited [0034] A PCTFE film may also be combined with a to 6 17 g/m 2 PVDC. To achieve a final dry coating weight PVDC layer. For example, a PVDC layer may be coated of for example 180 g/m2 PVDC, 10 or more repetitive on a substrate, followed by laminating a PCTFE film on coating/drying steps are necessary. This implies several the dried PVDC layer. Such a barrier film is disclosed in passes through an industrial coating alley. 55 US2011/0210037. [0028] The method disclosed in the unpublished EP- Halogen free barrier layers are preferably used in the A 12198387.8 (filed on 20-12-2012) makes it possible to present invention. When combined with a halogen free realize higher dry coating weights (DCW) of PVDC in a substrate, the blister pack of the present invention is com-

3 5 EP 2 801 475 A1 6 pletely halogen free. yesters. A preferred primer is a based prim- [0035] Such a halogen free barrier layer may be based er. on ethylene vinyl acetate copolymers, such as for exam- [0044] The lidding foil may comprise an ink accepting ple the Exceval ™ polymers available from Kuraray. Such layer to render the foil printable. Such a layer typically Exceval™ polymers are water soluble ethylene vinyl ac- 5 contains a polymeric binder and porous inorganic parti- etate copolymers with varying degrees of hydrolysis and cles. can be carried out by letterpress, gravure, ethylene contents. Barrier layers containing such Ex- offset, flexographic, silk-screen or inkjet printing process- ceval™ polymers may be coated from aqueous solutions. es. [0036] A halogen free barrier film may also be based [0045] A sealing layer may be provided to ensure a on acrylic resins, such as for example VaporCoat® from 10 good adhesion between the lidding foil and the blister Michelman. forming aluminium based laminate. Conventional heat [0037] Many halogen free barrier films are based on seal coatings may be used in the present invention. nanocomposites. For example the NanoSeal™ - Bairicade™ XT Barrier Blister Coating (BXT-50) and NanoSeal™ - Barrier coating 15 (NSC-60PL) from NanoPack are water based barrier [0046] In the blister pack according to the present in- coatings comprising clay platelets. vention, the cavity or blister forming foil comprises an The SunBar™ 1.1 Oxygen Barrier Coating (from Sun aluminium-based laminate film. Chemicals), a two parts blendable coating and also con- [0047] Unlike all plastic blisters, such alumunium taining clay platelets, may also be used to form a barrier 20 based blisters are not thermoformed but instead cold- film. pressed into shape. Such a aluminium based foil is typ- NanoLok™ WR 301409 from InMat, an aqueous suspen- ically referred to as a cold-formable foil (CFF). During the sion of nano-dispersed silicate and polyurethane resin, cold-forming process, the CFF is shaped and molded may also be used to form a transparent barrier film. around a plug to form a cavity. Such a CFF provides [0038] The MicroLite® vermiculite dispersions from 25 almost 100 % barrier to moisture, oxygen and light. Grace characterized by high aspect ratio vermiculate [0048] Because an has an elongation platelets provides high barrier properties to aqueous percentageof only 15 to18 %, a monolayer cold-formable coatings. The NanoShield® barrier films of Filquest are foil (CFF) cannot be formed without cracking. Conse- also based on vermiculate nano platelets. quently, the aluminium foil is laminated in a sandwich [0039] Ormocer®s are inorganic-organic hybrid poly- 30 between two polymers films. The aluminium-based lam- mers whose properties can be varied almost at liberty. inate typically contains in this order a plastic film, an ad- These hybrid polymers have been developed by The hesive, an aluminium foil, an adhesive, and an outer plas- Fraunhofer ISC and their preparation is based on a mod- tic film. ified sol-gel process. Barrier coating may be obtained [0049] The aluminium foil usually consists of several using such Ormocer® polymers. 35 very thin layers rather than a single thick one. The mul- [0040] The Aquamica® barrier coatings from AZ Elec- tiple layers help ensure that pinholes do not go all the tronicMaterials are basedon polysilazanes,i.e. polymers way through the foil. They also increase the stretchability in which silicon and nitrogen atoms alternate in the basic of the foil and facilitate the cold-stretching process. Spe- backbone. cial grades of aluminium have been developed for cold [0041] Barrier coatings based on the so called Dyad 40 forming. These are designed to stretch and form more technology may also be used in the present invention. easily than conventional grades. "Dyad" refers to a pair of layers comprising adjacent or- [0050] A preferred structure of an aluminium-based ganic and inorganic coatings. Such barrier coatings are laminate film is OPA/adhesive/aluminium/adhesive/PVC for example Barix multilayers from Vitex, barrier films (OPA is biaxially oriented ). from Tera-Barrier Films, and the Terraflex-F Gloss Coat- 45 [0051] OPA is used primarily for its forming capabili- ing G 11/182 from Actega. ties. It enhances the forming process due to its elasticity and it enables the formation of steep blisters allowing a Other layers high blister density to reduce blister size and material usage. [0042] The transparent lidding foil may, besides the 50 [0052] As adhesive, it is preferred to use a poly- substrate and the optional barrier layer, also comprise urethane based adhesive. additional layers to further optimize its properties. [0053] PVC is used for two reasons. First, it is com- [0043] For example, an "anchor coating" or primer may monly used as the contact layer and seal-to layer on phar- be applied on the substrate to improve the adhesion be- maceutical blisters. The second reason is that PVC is tween the barrier layer(s) and the substrate. Such a prim- 55 very stiff,and does nottend to shrink orspring backduring er is preferably coated from an aqueous coating solution. cold forming. Once the cold-forming process is complete, Such primers typically comprise one or more binders, the PVC helps the cavity to hold its shape. suchas for example , polyacrylics, and pol- [0054] An example of such an aluminium-based lami-

4 7 EP 2 801 475 A1 8 nate film is for example the Alublis® laminate from SVAM transparent barrier film has a Total Light Transmis- Packaging Ind. sion (TLT), measured according to ASTM D1300, of at least 80 %. Preparation of the blister pack 5 3. The blister pack according to claim 1 or 2 wherein [0055] A blister pack is typically made by a highly au- the transparent barrier film comprises a substrate tomated process. In a state of the art blister equipment, (22) and optionally one or more barrier layers (21) two foils are used: the foil in which the blisters are made provided on the substrate. (the lower web) and the foil used as lidding foil to seal the blisters containing the pharmaceutical product (the 10 4. The blister pack according to claim 3 wherein the upper web). For the blister pack according to the present barrier layer is a PCTFE film having a thickness of invention, the foil in which the blisters are cold-formed is at least 50 mm. the aluminium based foil (30). First, the blisters are formed in the alumunium based foil(35) by shaping and 5. The blister pack according to claim 3 wherein the the foil around a plug to form the blister cavity. 15 barrier layer is a PVDC layer having a dry coating Then, the pharmaceutical is deposited into the blisters weight between 40 and 180 g/m2. formed (40). The transparent lidding foil (45) then seals the blisters (50), resulting in a blister pack according to 6. The blister pack according to any of the claims 3 to the present invention (55). Most new blister equipment 5 wherein the substrate is a halogen free substrate. has the ability to use both thermoforming and cold-form- 20 ing foils. Older thermoforming equipment may require 7. The blister pack according to claim 6 wherein the the addition of a cold-forming module. Manufactures in- substrate is a polyester substrate. clude Uhlman Pac-Systeme GmbH&Co, KG, Marches- ine Group S.p.a, IMA S.p.a, Romaco and Korber AG. 8. The blister pack according to claim 7 wherein the [0056] Blister packs can be opened in several ways. 25 polyester substrate is a biaxially oriented polyethyl- Access to the medicament packed in a blister can be eneterephtalate (BOPET) substrate. given via push-through wherein the consumer must use a finger to push against the blister until the medicament 9. The blister pack according to any of the claims 5 to is pressed against and breaks through the lidding foil. 8 wherein the barrier layers are halogen free. [0057] In the "peel-push" type of blister package, the 30 consumer must first peel away an upper layer of the - 10. The blister pack according to any of the preceding ding foil, and then push against the blister until the med- claimswherein thetransparent barrier film is halogen icament is pressed against and breaks through the re- free. maining layers of the lidding foil. The "peel-push" type package is considered more child-proof than the strictly 35 11. A process to prepare a blister pack as defined in push-through type due to the extra layer of the lidding claims 1 to 10 comprising the steps of: foil that has to be removed first. [0058] Another way to open a blister pack is using the - cold-forming blisters (35) in an aluminium tear-open mechanism, wherein the complete lidding foil based foil (30), is removed from the blister, given access to the medica- 40 - depositing a pharmaceutical product into the ment. The latter two methods require the proper selection cold-formed blisters (40), of suitable sealants and adequate finishing (for example - sealing the blisters containing the pharmaceu- the presence of a notch to remove the lidding foil or the tical product (50) with a transparent lidding foil upper layer of the lidding foil). (45). j [0059] The latter two methods may be implemented 45 for child-proof reasons, or may become necessary when the transparent lidding foil according to the present in- vention is hard to break by a push-through mechanism.

50 Claims

1. A blister pack comprising a cavity forming foil (1) an a lidding foil (2)characterized in that the cavity formed foil comprises an aluminium-based laminate 55 film and the lidding foil is a transparent barrier film.

2. The blister pack according to claim 1 wherein the

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REFERENCES CITED IN THE DESCRIPTION

This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description

• EP 12198387 A [0028] • US 20110210037 A [0034]

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