Lidding film for blister packs and blister packs

Abstract

The invention relates to a lidding film for a backing film of a blister pack, comprising two outer layers, namely a top layer and a sealing layer, and one or more intermediate layers arranged between the top layer and the sealing layer. The invention also relates to a blister pack. The object of the invention is to dispense with aluminium while at the same time meeting the high-barrier requirements of high-quality pharmaceuticals with respect to water and oxygen at low cost. This is achieved by the invention described here in that the top layer and the sealing layer are polypropylene layers.

Description

Technical Field

[0001] This invention relates to a capping film for blister packaging, comprising two outer layers, namely a top layer and a sealing layer, and one or more intermediate layers disposed between the top layer and the sealing layer. The invention also relates to a blister packaging. Background Technology

[0002] Especially for high-quality pharmaceuticals, packaging is essential to protect the drug from environmental influences, particularly oxygen and moisture. This is the only way for the active ingredient or pharmaceutical component to maintain its intended effect upon ingestion. Therefore, so-called blister packaging is commonly used for tablet-form drugs. It typically consists of a push-through blister and a cap film. The push-through blister, also known as the bottom component or bottom film, is a molded part with recesses or cavities, usually made of plastic but can also be made of aluminum. The cap film, also called the blister membrane, is usually push-through and is primarily made of aluminum, allowing the medication to be pushed out of the cavity in the bottom film through the cap film. The fundamental advantages of blister packaging are its ease of use, compact size, and the ability to easily carry the corresponding medication while protecting it from any environmental influences.

[0003] The primary use of aluminum here is to isolate the drug from water and oxygen, as aluminum has high water vapor and oxygen barrier properties. Simultaneously, depending on the strength or thickness of the membrane, the corresponding drug in the cavity of the bottom membrane can be relatively easily extruded from the blister pack by the user through the top membrane. However, as an energy and resource-intensive material, aluminum, although recyclable, still requires a significant amount of energy.

[0004] Therefore, different methods are known from the prior art for reducing or completely removing aluminum from blister packaging while providing the same material properties as aluminum.

[0005] For example, a blister pack is known from DE 10 2008 056 123 A1, which comprises a multilayer film specifically composed of different plastic or polymer layers, thus completely eliminating the need for aluminum. In particular, this is a deep-drawable multilayer film with low water vapor and oxygen permeability, suitable for pharmaceutical blister packaging and preferably having a layered combination of PVC / PVDC / PCTFE / PVC type.

[0006] Furthermore, US2009 / 0208729 A1 discloses a membrane structure characterized by comprising at least five layers. It has two outer layers composed of polyolefin, with a gas barrier layer disposed on opposite sides of each outer layer, wherein a foam plastic layer is disposed between the two gas barrier layers. Both outer layers are composed of a mixture of polyolefin and an adhesive, which allows the polyolefin layer to bond to the gas barrier layer.

[0007] US2019 / 0009963 A1 discloses a plastic film molding article for blister packs, particularly tablet blister packs, comprising a transparent carrier substrate having a translucent functional layer. The translucent functional layer is formed in such a way that the plastic film molding article has a first visually recognizable color when viewed under incident light and a second visually recognizable color when viewed under transmitted light.

[0008] Furthermore, a polyolefin blister pack is known from German utility model DE 20 2021 002 835 U1, which has one or more recesses formed by thermoforming for receiving articles to be packaged, and is composed of a cover film attached to a bottom film. This blister pack is characterized in that the bottom film and the cover film are substantially composed of polyolefin, and at least 50% by weight of the cover film is composed of a cyclic olefin polymer.

[0009] Additionally, a method for producing a cover film for push-through packaging is known from Swiss patent application CH 701 216A1. In this method, the cover film is irradiated with electrons to set the desired push-through properties. Summary of the Invention

[0010] Based on this prior art, the object of the present invention described herein is to provide a blister pack, a cap film, and a bottom film, each of which can eliminate the need for aluminum and be used to meet the high barrier requirements of high-quality pharmaceuticals to water and oxygen at low cost.

[0011] This objective is achieved by a capping film according to applicable claim 1. Furthermore, this objective is achieved by blister packaging according to independent claim 17. Advantageous embodiments can be found in the dependent claims.

[0012] A first aspect of the invention relates to a cover film for sealing the bottom film of a pharmaceutical blister pack, comprising two outer layers, namely a top layer and a sealing layer. Thus, the cover film itself is a multilayer film, wherein the top layer is the side of the cover film facing the outside or environment. The sealing layer is the side of the cover film facing the drug within the cavity where the bottom film is typically located. Between these outer layers, namely the top layer and the sealing layer, there are one or more intermediate layers.

[0013] The significant feature of this invention is that the top layer and the sealing layer are composed of polypropylene, i.e., they are polypropylene layers. Polypropylene is comparable in price to polyvinyl chloride, which is often used in blister packaging or the cover and bottom parts of blister packaging, but has a higher water vapor barrier.

[0014] To reduce brittleness and the force required to propel the corresponding drug from the bottom component through the capping membrane, in an advantageous embodiment, the invention provides for one or more intermediate layers between the two outer layers of the capping membrane to be copolymer layers, preferably multiphase copolymer layers. This is particularly preferred in this context as multiphase polypropylene copolymer layers. Multiphase copolymer layers, also known as block copolymers, comprise a polymer matrix having a dispersed rubbery copolymer phase. This matrix is ​​a homopolymer or statistical copolymer matrix. The rubbery copolymer phase is a mixture of amorphous rubber, rubbery polymers (typically ethylene / propylene copolymers (rubber) in multiphase polypropylene copolymers), and semi-crystalline copolymers.

[0015] At least one copolymer layer in one or more intermediate layers preferably has a layer thickness of 20 to 260 μm, particularly preferably 100 to 180 μm. At such a layer thickness, the capping film remains compact while improving mechanical properties, namely the user's ability to push through the tablet form of the drug.

[0016] Alternatively or additionally, in another advantageous embodiment, the invention further includes one or more intermediate layers comprising at least one talc-reinforced polypropylene layer for the cover film. The talc-reinforced polypropylene is, for example, a composition of polypropylene and talc, wherein the proportion of talc typically varies from 20% to 35%. Compared to pure polypropylene, this talc-reinforced polypropylene exhibits higher heat resistance and load-bearing capacity, as well as higher rigidity. However, the latter property means that the plastic is also more prone to cracking. However, depending on the thickness of the talc-reinforced polypropylene layer, this property is precisely what is needed to allow for easier push-through of the cover film.

[0017] Furthermore, in another advantageous embodiment, the invention provides one or more intermediate layers for the cover film comprising at least one cyclic olefin layer, preferably a cyclic olefin copolymer layer. The presence of the cyclic olefin layer significantly improves water vapor barrier properties, the degree of which can be easily varied by the layer thickness of the cyclic olefin layer, which can range from 20 to 260 μm, preferably from 80 to 100 μm, and particularly preferably 80 μm. This latter layer thickness represents the optimal trade-off between improved water vapor barrier properties and the push-throughability required by the cover film.

[0018] However, in order to also meet the high oxygen barrier requirements of some drugs, in another advantageous embodiment, the present invention provides one or more intermediate layers for the capping film, including at least one polyvinyl alcohol layer, preferably an ethylene-vinyl alcohol copolymer layer. Polyvinyl alcohol is one of the best available oxygen barriers because the hydrogen bonds present within the polyvinyl alcohol are located between the polymer chains and connected to the crystal structure. The thickness of the polyvinyl alcohol layer is preferably 5 to 15 μm.

[0019] Depending on the desired characteristics of the cover film, in another advantageous embodiment, the invention provides different materials for the outer layer, i.e., the top layer and the sealing layer.

[0020] In a first alternative embodiment, the top layer and / or sealing layer consists of a polypropylene homopolymer layer. The difference between the polypropylene homopolymer and atactic polypropylene lies in the increased crystallinity, melting point, tensile strength, rigidity, and hardness due to the isotactic orientation of the groups (here, methylene groups). This high level of isotactic regularity ultimately leads to increased brittleness, which in turn improves the puncture resistance of the capping film. The thickness of the polypropylene homopolymer layer is preferably 10 to 140 μm, particularly preferably 60 to 110 μm.

[0021] In another alternative embodiment, the top layer and / or sealing layer consists of a polypropylene copolymer layer. Here, a distinction can be made between polypropylene block copolymers and polypropylene random copolymers. In the case of polypropylene block copolymers, the copolymer monomers are constructed into the polymer chain in a block form, while in the case of polypropylene random copolymers, they are incorporated into the molecular chain in a random distribution. The properties of the resulting polypropylene copolymers can be particularly affected by the different lengths and amounts of copolymer blocks or the corresponding block copolymer monomers used. In particular, their toughness behavior and rigidity are affected. Ultimately, the use of the polypropylene copolymer layer can also affect the penetration brittleness or toughness of the cover film.

[0022] In another alternative embodiment, the top layer and / or sealing layer consists of a nucleated polypropylene homopolymer layer. Nucleation or nucleation can be used to promote the formation of crystalline regions in atactic polypropylene. This is because the mechanical properties of polypropylene are affected by the size and type of the existing crystal structure. Since not all regions of the polypropylene chain are isotactic or syndiotactic, not all regions of the polymer chain can be incorporated into the crystallites. Typically, isotactic regions of the polypropylene homopolymer crystallize in the form of α-spherulites. However, the addition of a suitable or special nucleating agent may lead to the formation of β-spherulites, which is accompanied by an increase in the impact toughness of the polypropylene obtained from them. Therefore, depending on the desired properties and application, it is advantageous to use a nucleated polypropylene homopolymer with α-spherulites or β-spherulites as the top layer and / or sealing layer of the capping film. This nucleated polypropylene homopolymer layer is particularly preferably 120 to 200 μm thick.

[0023] To further improve the barrier properties against water vapor and oxygen, in another advantageous embodiment, the invention provides a sealing varnish applied to the sealing layer. This varnish further enhances the barrier properties against water vapor or oxygen without unduly negatively impacting the desired performance of the capping membrane, particularly its brittleness and resistance to punctures by any medication.

[0024] To provide child protection for any pharmaceutical blister pack, existing technologies typically increase the thickness of the aluminum foil layer or design the blister pack so that the cap film cannot be pushed open but can only be pulled open with force incapable of being applied by a child. To further provide child protection for the blister packs described herein, in another advantageous embodiment, the invention provides a barrier coating, preferably a removable barrier coating, on the top layer of the cap film. This coating is particularly preferably a biaxially oriented polypropylene (BOP) layer. BOP acquires its special properties through a special stretching method in which it is first stretched along the roller direction, then stretched perpendicular to the roller direction, and then fixed. Its primary characteristics are high tensile strength, chemical, mechanical, and thermal stability, and transparency. Therefore, it is ideally suited to protect any pharmaceutical blister pack from accidental opening by a child, as it is applied to the cap film and cannot be removed from the bottom component of the blister pack without sufficient force.

[0025] In a second and final aspect, the present invention relates to a pharmaceutical blister pack comprising a capping film according to the invention. Attached Figure Description

[0026] The invention will now be explained in more detail with reference to exemplary embodiments.

[0027] In the attached image:

[0028] Figure 1 A schematic diagram of a multilayer film according to the present invention is shown;

[0029] Figure 2 A first exemplary embodiment of the multilayer cover film according to the present invention is shown;

[0030] Figure 3 A second exemplary embodiment of the multilayer cover film according to the present invention is shown;

[0031] Figure 4 A third exemplary embodiment of the multilayer cover film according to the present invention is shown; and

[0032] Figure 5 A fourth exemplary embodiment of the multilayer cover film according to the present invention is shown.

[0033] List of reference numerals

[0034] 1 Cover film

[0035] 2. Bottom film

[0036] 3 Top Floor

[0037] 4 sealing layers

[0038] 5 intermediate layers

[0039] 6 polypropylene homopolymer layers

[0040] 7 copolymer layers

[0041] 8-cyclic olefin layer

[0042] 9 layers of polyvinyl alcohol

[0043] 10 nucleated polypropylene homopolymer layers Detailed Implementation

[0044] Figure 1 A schematic diagram of a multilayer film according to the present invention is shown. Both the cap film 1 and the bottom film 2 consist of two outer layers, namely a top layer 3 and a sealing layer 4. The top layer 3 is the side of the cap film 1 facing the outside or environment. On the other hand, the sealing layer 4 is the side of the cap film 1 facing the drug within the cavity where the bottom film 2 is normally located. Between these outer layers, namely the top layer 3 and the sealing layer 4, there are one or more intermediate layers 5.

[0045] Figure 2 A first exemplary embodiment of the capping film 1 according to the invention is shown here. It comprises two outer layers and an intermediate layer 5, wherein the top layer 3 and the sealing layer 4 are polypropylene homopolymer layers 6, and the intermediate layer 5 is a copolymer layer 7, particularly a multiphase random copolymer layer. This is suitable for drugs that are not very sensitive to water and oxygen, and because the intermediate layer 5 is significantly larger than the outer layers, it is easily punctured, as the intermediate layer 5, made of multiphase random copolymer 7, is more brittle or rigid and therefore less elastic than the polypropylene homopolymer layer 6.

[0046] Figure 3 The image shows a cover film 1 according to the invention, which is also suitable for water-sensitive drugs. It has a cyclic olefin layer 8 as an intermediate layer 5 between two polypropylene homopolymer layers 6 (as a top layer 3 and a sealing layer 4).

[0047] In order to provide waterproof and oxygen protection, Figure 4 The corresponding cover film is also shown. It also includes polypropylene homopolymer layers 6 serving as the top layer 3 and sealing layer 4, respectively, and a total of three intermediate layers 5. The first two intermediate layers 5 directly adjacent to the outer layers, i.e., the top layer 3 and sealing layer 4, are each cyclic olefin layers 8. Finally, a polyvinyl alcohol layer 9 is arranged between the two cyclic olefin layers 8, which has a high oxygen affinity due to its material properties. Therefore, Figure 4 The cover membrane 1 shown has high water vapor barrier and oxygen barrier properties.

[0048] at last, Figure 5 A cover film 1 according to the invention is shown, wherein the two outer layers, namely the top layer 3 and the sealing layer 4, are nucleated polypropylene homopolymer layers 10, and it has three intermediate layers 5. Here, cyclic olefin layers 8 are respectively adjacent to the two outer layers, and the cyclic olefin layers surround the multiphase random copolymer layers 7.

[0049] Therefore, the above illustrates a capping film and pharmaceutical blister packaging for blister packaging, which eliminates the need for aluminum in the film and meets the requirements for high water vapor and oxygen barrier properties at a low cost.

Claims

1. A cover film (1) for sealing a bottom film (2) of a pharmaceutical blister pack, the cover film (1) comprising two outer layers, namely a top layer (3) and a sealing layer (4), and one or more intermediate layers (5) disposed between the top layer (3) and the sealing layer (4), characterized in that, The top layer (3) and the sealing layer (4) are nucleated polypropylene homopolymer layers (10), and the one or more intermediate layers (5) include a plurality of cyclic olefin layers (8), and a polyvinyl alcohol layer (9) or a copolymer layer (7) is arranged between the cyclic olefin layers (8).

2. The cover film according to claim 1, characterized in that, The cyclic olefin layer (8) is a cyclic olefin copolymer layer.

3. The cover film according to claim 1, characterized in that, The thickness of the cyclic olefin layer (8) is 20 to 260 μm.

4. The cover film according to claim 3, characterized in that, The thickness of the cyclic olefin layer (8) is 80 to 100 μm.

5. The cover film according to claim 4, characterized in that, The thickness of the cyclic olefin layer (8) is 80 μm.

6. The cover film according to claim 1, characterized in that, The one or more intermediate layers include at least one polyvinyl alcohol layer (9).

7. The cover film according to claim 6, characterized in that, The polyvinyl alcohol layer (9) is an ethylene-vinyl alcohol copolymer layer.

8. The cover film according to claim 6, characterized in that, The polyvinyl alcohol layer (9) has a thickness of 5 to 15 μm.

9. The cover film according to claim 6, characterized in that, The one or more intermediate layers (5) include at least two cyclic olefin layers (8), with a polyvinyl alcohol layer (9) disposed between the cyclic olefin layers.

10. The cover film according to claim 1, characterized in that, The thickness of the nucleated polypropylene homopolymer layer (10) is 120 to 200 μm.

11. The cover film according to claim 1, characterized in that, A sealant is applied to the sealing layer (4).

12. The cover film according to any one of claims 1-11, characterized in that, The top layer (3) has a removable barrier coating.

13. The cover film according to claim 12, characterized in that, The barrier coating is a biaxially oriented polypropylene layer.

14. A pharmaceutical blister pack comprising a capping film (1) according to any one of claims 1 to 13.

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