PTP blister foil (Press-Through-Package blister foil) is a commonly used packaging material in the pharmaceutical industry. It is designed to provide a barrier against moisture, oxygen and other external contaminants, ensuring the integrity and shelf life of the encapsulated drug product. The construction of PTP blister foils usually involves multiple layers, each with a specific purpose. While exact ingredients may vary by manufacturer and specific requirements, the following is a typical structure:

Outer layer: The outer layer is usually made of a printable material on which product information, branding, and instructions can be printed. This layer provides protection for the inner layers and contributes to the overall appearance of the blister pack.

Heat-seal varnish: The next layer is heat-seal varnish, which is used to ensure a strong bond between the blister foil and the blister card during the sealing process. It creates a secure seal to protect products from environmental elements.

Aluminium foil: The core layer is made of aluminum foil, which plays the role of blocking moisture, oxygen and light. Aluminum foil does a good job of maintaining the stability and effectiveness of pharmaceutical products and preventing them from degrading due to exposure to these external elements.

Heat-sealing varnish: Apply a layer of heat-sealing varnish on the other side of the aluminum foil to facilitate the sealing of the aluminum foil and the blister card.

PVC or PVdC layer: According to specific requirements, a layer of polyvinyl chloride (PVC) or polyvinylidene chloride (PVdC) is coated on the inside of the aluminum foil. This layer acts as a forming film, forming individual blisters to securely hold the drug tablet or capsule.

The above layers are usually bonded together using various adhesives and coating techniques to form a single, flexible and protective PTP blister foil. This is essential to maintain the quality and efficacy of the attached pharmaceutical product throughout its shelf life.