Alu-Alu blister and PVC/PVDC blister compared – aluminum foil, blister, laminates

The pre-selection process follows a clear order: First, the stability of the drug in the intended blister must be proven to be maintainable and under the intended storage conditions. If a specifically specified PVC/PVDC version does not suffice to meet this requirement, that version is excluded. However, this does not automatically mean that an aluminum-aluminum blister is suitable; even it must provide the necessary protection as a finished packaging system. ^[5]

If both systems meet the protection requirement, format, actual process, and total costs per saleable package become the basis for decision-making. Recycling must be evaluated separately: Relevant are documented recovery routes for the specific composite material, not blanket judgments about aluminum or plastic.

Cold form and thermoform blisters: process and structure

Alu-Alu blisters and PVC/PVDC blisters differ primarily in the following aspects: Formbahn, That is, the foil from which the cavities are formed. The aluminum cover foil is not a definitive characteristic, because both systems can be hot-sealed with aluminum cover foil after filling. Therefore, one cannot conclude from the cover foil alone about the forming process or the moisture barrier. ^[1]

Cold forming refers only to the formation of the cavities. The packaging process is therefore not completely heat-free, because the filled package is then sealed. This distinction is practically important: Form processes and seal quality affect different parts of the final packaging performance. ^[1]

In a comparable specification, form width, layer structure, coating weight for PVC/PVDC, cover film, and sealing concept should therefore be clearly specified. Without these details, it is not possible to meaningfully assign a barrier or to cleanly compare formats or costs.

Moisture barrier: The finished package is the benchmark

A high moisture barrier of the form sheet is a strong selection argument, but not a guarantee for complete protection of the saleable package. In the case of the Alu-Alu blister, the aluminum layer of the form sheet provides the high barrier. In the case of the PVC/PVDC blister, the PVDC coating assumes this additional function. In both cases, the form sheet, the cover film, and the sealing area only together form the packaging system. ^{[1] [2]}

• PVC/PVDC is not a uniform protection class. The coating weight, layer structure and PVDC quality all influence the moisture barrier. Therefore, a general material description is not sufficient to classify a variant as suitable or unsuitable. ^[3]
• Even an aluminum barrier has system limitations. Moisture can diffuse across the sealing layer in cold forming blisters. Therefore, not only the mold sheet and the cover film must be considered in the assessment, but also the sealing area and the specific design. ^[4]
• Durability and storage conditions set the limit for selection. The stability data must relate to the intended primary packaging system. If a specified PVC/PVDC specification does not meet these requirements, that option is excluded. The suitability of an Alu-Alu system is therefore not yet proven and requires its own verification. ^[5]
• Only similarly defined systems are comparable. The number of doses, the target shelf life, storage conditions and the complete sealing and foil concept must be set as common bases. Only then can costs, volume and production data influence the selection.

The sealing layer deserves its own consideration: it combines form board and cover film, but is not simply a procedural detail. If its structure or the execution of the sealing seam changes, the performance of the finished blister can change, even though the form board designation remains the same. Stability data therefore cannot easily be transferred from one format or sealing concept to another.

Compare costs and volumes on the same performance basis

The price per square meter of the film is not a reliable decision factor. Economically speaking, complete packaging systems are compared with the same dosage amount, identical shelf life, and the same storage conditions. saleable packages, Not purchased film area, roll quantity or individual machine cycles.

Thermoformable PVC/PVDC structures can enable more compact blisters with sufficient barrier properties. However, this is not a general property of the entire material class. Whether a real pack format requires less volume depends on the cavity geometry, dose quantity, layout, outer carton, and shipping configuration. ^[6]

This data belongs in the comparison.

• Material consumption per pack: All film layers are recorded, including edge trim, misalignments, and waste. A lower cost per unit area can be offset by a higher loss percentage.
• Actual pack volume: The external dimensions and the storage and shipping volume of the finished package are compared with the same number of doses. The sheer blister area is insufficient because cavity depth, the outer carton, and the format layout all contribute.
• Usable line output: Cycles per minute should not be equated with salesable packs per minute. Packs per cycle, start-up times, rejects, reconfiguration and downtime all change the effective output. Therefore, published maximum values remain indicative of system- and format-specific considerations. ^[7]
• Total cost of processing: Tooling, conversion, material and processing costs must be related to the same number of saleable packages. Only then are the cost implications of a different format or process visible.

The same dose quantity prevents a skewed comparison. A pack with a different number of cavities or a different dosage amount may indeed consume less film area, but it answers a different procurement question. Only when both variants represent the same usable drug amount can material usage, carton quantity, and process complexity be reduced to a common unit of performance.

Practically speaking, the calculation can be structured as costs per marketable pack: The sum of material, tooling, conversion, and processing costs is divided by the actual packages released. In the numerator, the cost components from losses and waste are also included; in the denominator, they are not the theoretically calculated volumes but only the good packages. This method does not provide a price comparison without real input data, but it does show precisely which data are missing for it.

A reliable calculation does not require a blanket assumption about the „cheapest“ blister. It requires two suitable, fully specified systems and data for the actual saleable quantity. If loss rates, format allocation, or actual output are missing, no cost-saver can be proven.

Recycling: A means of recovery instead of a one-size-fits-all environmental judgment

Recyclability, actual recovery and environmental balance are three different statements. A composite can be technically separable without a suitable collection stream existing within the intended waste disposal area. Documentation of the continued use of individual fractions, however, does not yet constitute a closed loop for new blister packs.

For collected PVC/aluminium blisters, an operator describes a mechanical separation process. The PVC fraction is further processed into panels, among other things. The metal foil is melted down or used in other ways. This proves a concrete route for the collection stream being processed there. It does not support a blister-to-blister loop nor any specific statement regarding PVC/PVDC structures or classic PVC/aluminium blisters. ^[8]

From the current available data, no ecological winner can be derived. The lack of equivalent practice data for another combination is not a negative environmental assessment but an evidence gap. A recycling claim is only credible for procurement purposes if it relates to the specific film structure, the actual collection stream, the separation, and the documented subsequent use.

• Verbund specifies: The statement must cover formwork, coatings, cladding foil and other relevant layers.
• Assigning the collective current: A disposal route is only decisive if the package can actually be supplied to this flow in the intended market.
• Name the follow-up application: The use of separately collected fractions must be distinguished from a closed loop for new packaging.

Selection matrix: What information changes the decision?

The matrix translates the order of stability, format, cost, and recycling into concrete selection sequences. It does not replace product approval, but it does show which missing information still leaves a decision open.

Hypothetical decision case

Both systems meet the stability requirements at the same dose rate, same target shelf life and same storage conditions. The PVC/PVDC format is more compact. However, there are no reliable data on waste generation, retrofitting and actual output. The consequence: The more compact format remains a candidate for lower pack and shipping volumes, but it is not yet a proven cost saver.

In this case, there are mainly three pieces of information that are lacking for the cost decision: the material loss per package, the number of saleable packages in actual line operation, and the effort required for tool changes or retrofits. If the loss percentage or the process effort of the compact format is unfavorable, its volume advantage can be economically offset. However, if these values are calculated on the same basis for both variants, the open cost question can only be decided upon. Until then, it is already clear: The protection is met under the assumed conditions, and the compact format remains comparable.