A blister pack for medication is the little card with the bubbles. Each bubble holds one tablet, sealed under a thin layer of foil or paper. You press the tablet through, and the rest of the doses stay protected in their own pockets.
That sounds basic. The interesting part is what the format quietly does in the background: it keeps every dose dry, dark, and tamper-evident, gives the patient a way to track whether they took yesterday's pill, and stops the whole pack from going stale just because they opened one cavity. None of that is true for a bottle.
What is actually inside a blister pack
Two layers do the work. The forming film on the bottom is what gets shaped into cavities, usually from PVC, PVDC-coated PVC, ACLAR, or a cold-formed aluminum laminate (Alu-Alu). On top sits the lidding foil, almost always aluminum with a heat-sealable or cold-sealable coating. The patient pushes the tablet through the foil, the foil tears, and the tablet pops out.
The choice between PVC, PVDC, ACLAR and Alu-Alu is not aesthetic. It's stability data. Hygroscopic APIs that draw moisture out of the air need Alu-Alu. Light-sensitive APIs need ACLAR or aluminum. Stable formulations get PVC because it's cheap and works fine for them. We pick the material from your stability study, not from a price list.
The blister wallet variation
A regular blister card sits inside a folded carton with a leaflet. A blister wallet bonds the blister to a paperboard wallet directly, often with cold seal adhesive instead of heat. That changes a few things: the wallet itself becomes the printed surface, you can lay out a calendar across it, and the cold seal step doesn't expose the API to heat. Cold seal blister wallets are what we run for the majority of our pharma customers, especially when the medicine has a long course or a complex schedule.
Why patients (and regulators) like the format
A patient can glance at a blister wallet and see whether they've taken their Wednesday morning dose. That's not a small thing for someone managing seven medications. Calendar wallets lift adherence by roughly 30% in published studies, which translates into fewer hospital readmissions and better trial outcomes.
Regulators like blister packs because they're inherently tamper-evident. A torn foil is obvious. The EU's Falsified Medicines Directive made tamper-evidence mandatory for prescription medicines in 2019, and most companies satisfied that with foil-sealed blisters and a 2D Data Matrix code on the carton.
Where blister packs go wrong
Two recurring failure modes. The first is barrier mismatch: someone picks PVC for an API that turns out to be hygroscopic, then watches the stability data crash at month nine. The second is patient usability: a senior with arthritis can't push the tablet through, or a child can. Neither problem shows up in a quote, both show up in audits.
If you're shipping a new tablet, the smart move is to spec the blister against the stability study early, then test the format with the patients who will actually use it. We help our customers with both. Send us your stability data and target patient profile and we'll come back with two or three blister formats that match. Or request a physical sample if you want to feel the difference between PVC and Alu-Alu in your hand.
Request a free sample now!
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