Alu Alu is the most expensive blister pack option – we estimate the cost per pack to be 50% higher than traditional PVC-based blisters. But in return for paying a premium, users get the best barrier protection for their products.
However, anecdotal evidence from the market suggests that the majority of products in Alu Alu blister form do not actually require this level of impermeability – packers and manufacturers are choosing Alu Alu as a “belts and braces” strategy.
Read the FAQs below to help manufacturers make the best packaging choices.
Q: What is an Alu Alu blister
A: On an Alu Alu or CFF (Cold Formed Foil) blister pack both the base and lidding are made from the aluminium-based film: OPA-ALU-PVC (nylon-ALU-PVC), making it possible to almost entirely eliminate water vapour permeability as well as oxygen and light ingress. These blister packs are made via a cold forming technique in which the laminate is pressed into a mould without applying heat, using forming pins to create the product cavity. The pack is then sealed with an aluminium lidding material.
Q: Why might a product need Alu Alu packaging?
A: It is essential that the Active Pharmaceutical Ingredient (API) remains stable in the finished product until the end of its shelf life to ensure efficacy and patient safety.
Stability can be compromised by thermal degradation, oxidization, UV, microorganisms, or hydrolysis. There are a number of formulation technologies that can protect the API; tableting excipients that will absorb water and film coatings that prevent moisture from reaching the core, for example.
It is estimated that 25% of pharmaceutical products on the market are sensitive and require optimal moisture protection. Products that are typically packed in Alu Alu blisters include effervescent tablets and high-value, high-potency drugs. Ultimately though, stability testing is the only way of determining whether an individual product requires that level of insulation.
Q: Why not use alu/alu for all blister-packaged pharmaceutical products?
A: Because it is expensive. The cost of the OPA-aluminium-PVC laminate is higher than PVC and cold-formed blisters require more packaging material than thermoformed blisters for packaging the same number and size of tablets or capsules. This is primarily due to the limitations of the cold-forming process, which uses pins to press cavity geometry into a thin sheet of aluminum. Aluminum cannot be formed with near 90-degree angles, resulting in larger than necessary cavities and blister cards. Added to this are the slower speed of production for cold forming compared to thermoforming, the requirement for a dedicated feeder, the increased complexity of inspection due to the opacity of the cards, and the higher secondary packaging and logistics costs due to the larger packs.
Q: Why don’t thermoformed plastic-based blisters offer the same degree of protection?
A: PVC – the most widely used thermoforming film – is easy to form and cheap, but the protective properties of the resultant pack are not on par with CFF blisters because of PVC’s low resistance to moisture and oxygen ingress.
