Aluminum Foil For Pills Packaging

Aluminum foil for pills packaging is a core material in the pharmaceutical packaging industry. Its design and performance directly impact the stability, safety, and ease of use of pharmaceuticals.

1. Materials and Types

– PTP Aluminum Foil (Medicinal Sheet Foil)

Mainly made of 8011-H18 or 8011-O aluminum alloy, typically with a thickness of 0.016-0.04mm. This type of aluminum foil is heat-sealed with PVC rigid sheet to form individual blister packaging, widely used for solid pharmaceuticals such as tablets and capsules. Its core advantage is its complete barrier to oxygen, moisture, and light, effectively preventing pharmaceuticals from oxidation, deliquescence, and photodegradation.

– Cold-Formed Aluminum Foil (Blister Foil)

Using 8021-O aluminum foil with a thickness of 0.04-0.065mm, it is directly wrapped around pharmaceuticals through cold stamping technology. Compared to PTP aluminum foil, it offers greater mechanical strength and is suitable for high-end pharmaceuticals or applications requiring stringent sealing requirements, such as injectable packaging.

– Tropical Aluminum Foil (Aluminum-Plastic-Aluminum)

Combining a thermoformed plastic blister with a cold-stamped aluminum foil cover creates a three-layer “aluminum-plastic-aluminum” structure, providing dual-barrier protection. This design is particularly suitable for pharmaceuticals requiring long-term storage or requiring complex transportation environments, such as antibiotics and medications for chronic diseases.

2. Key Performance Indicators

– Barrier Properties

Aluminum foil’s metallic crystal structure provides a complete barrier to gases and water vapor, with oxygen and water vapor transmission rates approaching zero.

– Heat Seal Strength

The heat seal layer (usually polyethylene) must maintain heat seal stability for 1 second at 155°C ± 5°C and a pressure of 0.2 MPa to ensure a leak-free blister seal. Insufficient heat seal strength may expose the drug to the environment, leading to failure.

– Mechanical Strength

Burst Strength: A hydraulic test simulates transport extrusion, requiring the medicine aluminum foil to withstand a pressure of at least 30kPa at a flow rate of 95ml/min.

Cupping Value: This reflects the ductility of the aluminum foil. A high cupping value (such as 8011-H18 aluminum foil) can prevent rupture during blister molding.

3. Production Process and Quality Control

– Substrate Preparation

Aluminum ingots are rolled to the target thickness and then annealed to eliminate stress and ensure material flexibility.

– Coating

Heat-seal layer: Polyethylene or polypropylene is coated on one side of the aluminum foil to ensure thermal adhesion to the PVC rigid sheet.

Protective layer: A printing ink fixing layer is applied on the other side to prevent logo wear. Coating thickness and uniformity are controlled by measuring the adhesive application rate.

– Quality Inspection

Darkroom illumination: Pinhole detection is performed using a high-definition glass platform and black paper backing to ensure that even minor defects are visible.

Peel strength test: Using a DLS-07 instrument, the heat-seal layer is peeled off at a speed of 200 mm/min to verify bond strength.

4. Regulations and Safety Standards

International Standards

The EU BS EN 546-4:2006 sets requirements for specific properties of aluminum foil (such as corrosion resistance and surface roughness).

The US FDA requires that aluminum foil coating materials (such as adhesives) meet food and drug contact safety standards and prohibit the use of ingredients that may migrate harmful substances.

Safety Verification

Compatibility between aluminum foil and pharmaceuticals requires accelerated testing (such as stability testing under high temperature and high humidity conditions) to ensure the absence of chemical reactions or component migration. For example, the aluminum-plastic blister packaging of cephalexin capsules requires verification of the impact of aluminum foil on drug content and impurities.

5. Typical Application Cases

– PTP aluminum foil: Widely used in the packaging of antihypertensive drugs (such as candesartan) and antibiotic tablets, ensuring accurate and individually protected daily dosages.

– Cold-formed aluminum foil: Used for insulin pen cartridges, vaccines, and other biologics that require strict protection from light and moisture.

– Tropical aluminum foil: Antimalarial drugs in the Southeast Asian market are packaged in aluminum-plastic-aluminum packaging, ensuring drug stability in high-temperature and high-humidity environments.

Aluminum foil for pills packaging, due to its excellent barrier properties and stability, has become the “gold standard” for pharmaceutical packaging. With stricter regulations and increasing environmental demands, the industry is moving towards intelligent, lightweight, and green packaging. In the future, material innovations (such as bio-based coatings), process optimization (such as solvent-free lamination), and breakthroughs in recycling technologies will further consolidate aluminum foil’s core position in pharmaceutical packaging while also contributing to the achievement of sustainable development goals.