Pharmaceutical aluminum-plastic blister packaging, also known as PTP (Press Through Pack) packaging, is widely used for tablets and capsules. In this process, packaging films are shaped into cavities by thermal forming (thermoforming) or cold forming (cold-press forming). The drug is then filled into these cavities and sealed with a lidding material — usually aluminum foil coated with a heat-sealable lacquer — to form unit-dose packaging.
To overcome the limitations of conventional thermoformed blister packs in terms of barrier protection, cold-formed aluminum foil has been developed. Cold-formed foil uses a mechanical stamping process instead of thermoforming, enabling the use of pure aluminum composite material as the forming substrate. The application of high-strength aluminum alloy in cold-formed hard film gives the packaging superior barrier properties against moisture, oxygen, and light - levels that no other material can achieve.
Cold-formed aluminum foil blister packs are especially suitable for:
Moisture-sensitive pharmaceuticals
Easily oxidized pharmaceuticals
Light-sensitive pharmaceuticals
Temperature-sensitive pharmaceuticals (benefiting from the non-thermal forming process)
High-value medicines (where packaging cost is balanced by product value)
Advantages of Cold-Forming Aluminum Foil in Blister Packaging
1. Superior Barrier Properties
Cold-formed aluminum foil provides nearly 100% protection against moisture, oxygen, and light, effectively preventing drugs from absorbing moisture, oxidizing, or degrading. This makes it ideal for sensitive medications.
2. Extended Shelf Life
Due to its tight sealing and outstanding barrier properties, medicines are well protected during storage and transportation, significantly extending their shelf life.
3. Excellent Formability
Cold-formed foil has outstanding ductility, allowing the production of deep-drawn blisters, which are especially suitable for large capsules or tablets.
4. Enhanced Anti-Counterfeiting and Branding
The foil surface can be printed or laser-marked, supporting drug traceability and anti-counterfeiting measures, while also improving packaging aesthetics and enhancing brand image.
5. No Heat Damage
Unlike thermoforming, cold-forming technology avoids heat altogether, ensuring that drug quality remains unaffected during the packaging process.
Comparison with Traditional Thermoforming Blisters
Compared with thermoformed blisters, cold-formed aluminum blisters offer significant advantages.
Thermoformed blisters are typically made of PVC or PVDC films. They are relatively low-cost and suitable for conventional medicines but provide only limited barrier properties and cavity depth. Over time or in humid environments, their protective performance may degrade.
Cold-formed aluminum blisters, on the other hand, are formed at room temperature under mechanical pressure. They provide near-total barrier protection against moisture, oxygen, and light, making them especially suitable for moisture-sensitive, light-sensitive drugs, and large-dose capsules.
Although cold-formed blisters come at a slightly higher cost, their superior performance in terms of long-term stability, anti-counterfeiting, and suitability for international high-end markets makes them a more valuable solution compared to conventional thermoforming packaging.
Processing Requirements for Cold-Formed Pharmaceutical Aluminum Foil
1. Flat sheet profile.
2. Strict surface requirements: no oil spots, scratches, black streaks, bright lines, roll marks, dents, insect marks, or other defects.
3. No pinholes or perforations; any foil with pinholes must be rejected.
4. High-quality edge trimming: no burrs, telescoping, layer shifting, wavy edges, turned edges, or uneven surfaces.
5. Brushing quality must meet Grade A standards.
6. Moisture-proof packaging is required to prevent oxidation.