PTP (Press Through Pack) blister foil is a type of pharmaceutical packaging material used for the packaging of solid oral dosage forms, such as tablets and capsules. It consists of multiple layers that serve different purposes. The typical structure of PTP blister foil includes:

Protective Layer: The topmost layer of the foil is a protective layer, often made of polyester (PET). It provides protection against external factors such as moisture, light, and oxygen.

Printing Ink: A layer of printing ink may be applied on top of the protective layer. It can contain important information such as product name, dosage, and manufacturer details.

Aluminum Foil Layer: The aluminum foil layer is the core component of PTP blister foil. It provides excellent barrier properties, effectively protecting the medication from moisture, light, gases, and contaminants. Aluminum foil is typically around 20-30 microns thick.

Heat Seal Lacquer: The aluminum foil layer is coated with a heat seal lacquer on the inner side. This lacquer allows the foil to be heat-sealed to the blister packaging during the packaging process. It ensures the integrity and tamper-evident properties of the blister pack.

PVC or PVDC Layer: In some cases, a layer of polyvinyl chloride (PVC) or polyvinylidene chloride (PVDC) may be present on the bottom side of the aluminum foil. PVC or PVDC provides additional barrier properties and enhances the stability of the packaged medication.

It’s important to note that the specific structure of PTP blister foil can vary depending on the manufacturer, product requirements, and regional regulations. Different combinations of materials may be used to achieve the desired barrier properties, printability, and ease of use.