Film plays a crucial role in pharmaceutical packaging. Its core value lies in providing excellent barrier properties, which can effectively protect the drugs from external environmental factors, thereby ensuring the quality, safety and validity period of the drugs. 

The main application forms of aluminum foil in pharmaceutical packaging: 

The backing layer of the bubble wrap packaging (PTP - Push-Through-Package) 

Structure: This is the most common application form. The blister packaging consists of two parts: the lower layer is a molded transparent plastic sheet (usually PVC or PVDC) that is used to hold pills or capsules; the upper layer is an aluminum foil backing layer that covers it. 

Function: The main function of the aluminum foil backing layer is to provide complete sealing, preventing air, moisture, and light from penetrating onto the pills or capsules, thus avoiding their oxidation, moisture absorption, decomposition, or failure. When opening the package, it requires applying force to press and break the aluminum foil to remove the pills. 

Advantages: Unit-dose packaging, convenient for carrying and taking, each tablet/pill is independently sealed to prevent cross-contamination. 

2. Composite film/bag packaging 

Structure: A multi-layer structure formed by bonding aluminum foil with materials such as CPP, PET, PA, or paper through methods like hot pressing. 

Application: 

Powder and granule packaging: Such as cold medicine powder, vitamin powder, Chinese medicine granules, etc., are usually packaged in small bags made of aluminum-plastic composite film. This packaging method effectively prevents moisture, light exposure and oxidation. 

Liquid medicine packaging: For some oral liquids, the soft packaging may also use a composite film containing aluminum foil to enhance the barrier properties. 

Injection packaging: Some infusion bags and blood bags also use composite film materials containing aluminum foil. 

3. Inner lining of the bottle cap/bottom plug 

Structure: Inside the screw cap or stopper of a medicine bottle (especially a plastic or glass bottle), there is usually an aluminum-plastic composite sealing gasket (also known as an "aluminum-plastic combined cap"). 

Function: After tightening the bottle cap, this inner liner can closely fit the bottle mouth, achieving excellent airtightness and moisture-proof properties. It prevents the drugs inside from absorbing moisture or evaporating, and also prevents outside air and moisture from entering. Some models also come with a "tamper-proof ring" that will break once the bottle is opened, indicating that the drug has been accessed. 

4. Capsule shell 

Application: Although not as common as gelatin capsules, there are indeed aluminium foil-made empty capsules, which are mainly used to contain drugs that are extremely sensitive to light, oxygen, and moisture. 

Why is aluminium foil an ideal choice for pharmaceutical packaging? 

Excellent barrier properties: The aluminum foil can almost completely block out oxygen, water vapor, light and odors. This is something that plastics and papers cannot match and is crucial for maintaining the stability of medicines. 

Chemical stability: The aluminum foil itself is non-toxic, odorless, and has stable chemical properties. It does not react with medicines and will not affect the efficacy of the drugs. 

Excellent ductility: Easy to process and shape, it can be conveniently manufactured into various forms such as blister backing, composite films, etc. 

Cost-effectiveness: Compared to the protection performance it provides, the cost of aluminum foil is relatively manageable. 

Summary

Aluminum foil is an indispensable key material for modern pharmaceutical packaging, especially widely used in blister packaging and composite films. By providing reliable barrier protection, it ensures the safety and efficacy of the drugs throughout their validity period.