Pharmaceutical packaging materials must meet stringent requirements for compatibility, safety, and protection from environmental factors.
The primary classes of materials include:
Glass (Pharmaceutical packaging)
Types
Type I (Borosilicate Glass): Used for highly sensitive or parenteral formulations due to its superior chemical resistance and inertness.
Type II (Treated Soda-Lime Glass): Often employed in less demanding applications where some ion exchange is acceptable.
Type III (Soda-Lime Glass): Used for oral and topical formulations, but less ideal for sensitive drugs due to its higher reactivity.
Properties
Inert nature minimizes the risk of chemical interaction.
Excellent barrier properties against gases and moisture.
Fragile and heavier compared to other materials.
Plastics
Materials Commonly Used
Polyethylene (PE): Good chemical resistance and flexibility; available as high-density (HDPE) for bottles.
Polypropylene (PP): Lightweight, has good heat resistance, and is often used for caps and closures.
Polyethylene Terephthalate (PET): Noted for its clarity, strength, and barrier properties; frequently used for pre-filled syringes and vials.
Polyvinyl Chloride (PVC): Often used in combination with plasticizers for flexible packaging applications but may require careful formulation to avoid leachables.
Other Specialty Polymers: Such as cyclic olefin copolymers (COC) or cyclic olefin polymers (COP) which offer excellent optical clarity, low extractables, and high chemical resistance.
Properties
Lightweight and less brittle than glass.
Versatile in design (flexible, semi-rigid, or rigid structures).
May interact with certain formulations if not properly selected or treated.
Metals
Common Metals
Aluminum: Widely used for blister packs and secondary packaging; excellent barrier properties and corrosion resistance.
Stainless Steel: Used primarily in specialized containers, such as for parenteral packaging or controlled substances.
Properties
High durability and integrity under mechanical stress.
Can act as an effective barrier against light, oxygen, and moisture.
Often combined with inert coatings or liners to prevent interaction with pharmaceutical products.
Composites and Multi-layer Materials
Examples
Blister Packs: Often comprise a combination of aluminum foil (providing moisture and oxygen barrier) laminated with polymeric layers (providing mechanical strength and adhesion).
Multi-layer Bottles: May use inner polymer layers for drug compatibility and outer layers for mechanical strength.
Properties
Designed to maximize the individual benefits of each material used, such as combining barrier properties with strength and manufacturability.
Complex design may lead to challenges in recyclability and environmental impact.