CHEMFILM Used as a Barrier in Pharmaceutical Drug Containers and Delivery Systems

Specialty fluoropolymer films help preserve shelf life and enhance containment safety in pharmaceutical drug containment and delivery systems. The material is inherently inert, non-contaminating and when used as a barrier will not react with pharmaceuticals or other packaging materials. The film is typically laminated to an elastomer sealing substrate that effectively seals off containers, eliminates the possibility for contamination and prevents any amount of leaching from the elastomer stopper, closure or backing.

Saint-Gobain Specialty Films provides high-performance, engineered, fluoropolymer films that fulfill a diverse range of needs in pharmaceutical drug containers and delivery systems. Under the CHEMFILM^® brand are a breadth of product offerings, including skived, cast and extruded fluoropolymers. These high-performance fluoropolymer films are each tailored for the intended application, addressing a diverse set of needs from simple disc-shaped closures to highly developed geometries that must undergo lyophilization (freeze drying) or heat sterilization.

Conformability
CHEMFILM^® high performance fluoropolymer films are formable over a wide range of manufacturing temperatures. They exhibit exceptional elongation characteristics, highly uniform tensile properties and ideal stiffness characteristics.

Saint-Gobain Specialty Films can help identify an optimal solution that emphasizes substrate compatibility, economics and formability to help ensure safety of drug containment and delivery systems. They can provide a pinhole-free barrier material, a material that excels in sealing complex geometries, as well as more economical solutions that address a broad range of sealing requirements. The relative performance of their range of skived, cast and extruded fluoropolymers is depicted by the following diagram.

Figure 1: Spider diagram depicting relative cost, stiffness and elongation characteristics of CHEMFILM skived, cast and extruded fluoropolymers.

CHEMFILM fluoropolymer films address a diverse set of needs. Primary selection criteria includes cost, stiffness and elongation characteristics although compatibility with the elastomer closure system is another factor to consider.

For example, CHEMFILM T100 skived film is the most economical solution. It offers an inert barrier when a moderate stiffness modulus and lower elongation characteristics provide adequate protection. On the other end of the spectrum, CHEMFILM DF100 cast film is Saint-Gobain Specialty Films’ premium film, which provides the greatest tensile strength, lowest stiffness modulus and high elongation characteristics as is needed when dealing with highly developed geometries and septa applications.

To ensure optimal peel strength and enhance the reliability of drug containment, Saint-Gobain Specialty Films can leverage their experience with various surface treatments and fluoropolymer materials. They can identify possible solutions and help optimize the proper selection of materials and surface treatments that are most suitable for a particular packaging application.

Bondability of Fluoropolymers
Fluoropolymers are an inert material distinguished by exceptionally low surface energy. To improve wettability and subsequently bondability to various substrates, CHEMFILM high-performance polytetrafluoroethylene (PTFE), ethylene and tetrafluoroethylene copolymer (ETFE) and fluorinated ethylene propylene (FEP) films are enhanced by one of several surface treatments.

• C-treatment: A proprietary, modified, corona-based surface treatment used exclusively with CHEMFILM ETFE and FEP films. Cast PTFE films can be layered with FEP in order to add a C-treatment. Unlike other surface treatments, this treatment provides for little or no discoloration of the film, preserving its appearance.
• Chemlink™: A proprietary etching process that is available for PTFE films. Chemlink, like the C-treatment, maintains the natural coloration of the PTFE film.
• Chemical etch: A robust, deep-surface treatment that is available for a broad range of fluoropolymers. Chemical etching will often discolor the film, the degree of which is distinctive to the particular chemical etching process and intensity.
• Heat bonding: A thermoforming process where a layer of melt processable fluoropolymers are added to either one or both sides of the film. This treatment is predominantly used with cast fluoropolymers for bonding the film to itself or with some additional treatments to form a bond with other surfaces.

CHEMFILM Skived PTFE

CHEMFILM T-100 premium skived PTFE films are manufactured from high-quality virgin PTFE resins and are available with an etched surface that adheres to butyl rubber or elastomer substrates. These films exhibit outstanding heat and chemical resistance with continuous service temperatures up to 260° C (500° F).

Skived fluoropolymers are an excellent candidate for simpler geometries. In these applications where a pure PTFE film is desired and when the film is not subject to deep drawing, skived PTFE is an excellent choice. The inherently inert barrier film can be used to seal off the packaged contents within a vial or other simple containment system.

Performance Characteristics of CHEMFILM T-100 Premium Skived PTFE Films:

• Virgin PTFE film
• Excellent service and availability
• High-temperature film with a continuous service temperature up to 500° F
• Made bondable through chemical etching

CHEMFILM Cast PTFE Films

CHEMFILM DF1100 is a multilayer cast PTFE film with a modified surface that adheres to a variety of adhesives and elastomer backings. The cast fluoropolymer is available with a wide range of pigments and additives, providing a customized look and enhanced performance characteristics.

Cast fluoropolymers address critical demands as is required with highly developed stopper geometries. The multilayer construction reduces the risk for pinholes in septa applications and may also be used as a standalone barrier film.

Performance Characteristics of CHEMFILM DF1100 Multilayer Cast PTFE Films:

• Uniform tensile properties
• Isotropic shrinkage as a function of temperature
• High elongation
• Made bondable through a proprietary Chemlink layer

CHEMFILM Extruded Fluoropolymer Films

CHEMFILM ETFE-E4 and CHEMFILM FEP-FG are extruded fluoropolymer films manufactured from specialty grades of ethylene and tetrafluoroethylene copolymers and fluorinated ethylene propylene resins, respectively. They exhibit exceptional elongation characteristics over a wide operating temperature.

Extruded polymers are preferred in deep-drawn closure systems. These complex closure systems are often required when lyophilizating pharmaceuticals. The associated elastomer backings have multiple legs or pultrusions that fit inside the closure system. These backings require a film that will stretch and form without failure during the lamination process.

Performance Characteristics of CHEMFILM ETFE-E4 Films:

• Thermally stable thermoplastic with high elongation
• Thermoformable to shapes of high complexity
• Functional temperature range from -328°F to 330°F (-200°C to 165°C)
• Suitable for cryogenic and high-temperature applications

Performance Characteristics of CHEMFILM FEP-FG

• Excellent anti-stick release properties
• Exceptional chemical resistance
• Functional temperature range from -425°F to 400°F (-254°C to 205°C)
• Suitable for cryogenic and high-temperature applications
• Made bondable via C-treatment (modified corona process)

Conclusion

In support of next-generation drug containers and delivery systems, Saint-Gobain Specialty Films provides a wide range of high-performance fluoropolymer films. These uniquely bondable films adhere to a wide range of butyl rubber and elastomer sealing substrates and are available in several different chemistries. They serve as a high-performance barrier with excellent thermal stability over a wide temperature range. They prevent contents from coming in contact with the sealing device in a range of applications, including deep-draw films for highly developed geometries, pinhole-free films for drug delivery systems, as well as economical skived films for low-profile disc stoppers and two-dimensional sealing devices.

This article was produced by IEEE GlobalSpec. Visit the Saint-Gobain Specialty Films' Engineering360 page on IEEE GlobalSpec here.