Medical pouching is an innovative segment of standard packaging used primarily for delicate or sterile medical devices and disposables. The trend toward thinner, less expensive materials and components may be beneficial for the bottom line, but not all materials and assemblies are made equal. One packaging-related recall can be catastrophic for a medical OEM or contract manufacturer. The threat of a letter from the FDA due to poor seals, pinholes, tears, or other packaging defects should completely underscore the importance of ensuring quality in every pouch.
According to the U.S. Centers for Disease Control and Prevention, medical devices categorized as “critical items”, such as surgical instruments, cardiac and urinary catheters, implants, and ultrasound probes should be sterile. Devices considered “semicritical” include items that contact mucous membranes or non-intact skin that require high-level disinfection, including respiratory therapy and anesthesia equipment, some endoscopes, laryngoscope blades, esophageal manometry probes, cystoscopes, anorectal manometry catheters, and diaphragm fitting rings. Lastly, “noncritical” items that come into contact with intact skin require neither sterilization nor disinfection, largely because there is very little chance of infection.
In addition to sterility, packaging designers must be mindful of the overall durability and strength of pouching materials to ensure they meet the specifications that are required for their application. Factors such as the pouch environment, visual inspection via optically clear materials, high-barrier protection, point of use, storage conditions, sterilization, and clean room conversion/assembly, all impact the material selection. Once the material is selected, which can range from high-end DuPont™ Tyvek® films to standard medical- grade paper, it’s important to determine the methods used in manufacturing, which include rotary die-cutting and sealing, automated laser cutting systems, humidity infusion, vacuum sealing, and other services. (See Figure 1)
As part of the product development process, medical device manufacturers are now specifying pouching materials in order to ensure compliance from production through the point-of-use. Medical pouches can be created using a wide range of materials from suppliers like DuPont and 3M, depending upon the application requirements.
Types of materials used for pouches include: Tyvek, foils, film, and papers.
Tyvek provides very good microbial resistance, preserving sterility of the medical device or pharmaceutical inside the pouch until opened. It is superior to medical-grade papers and films due to compatibility with the broadest range of sterilization methods, and features high puncture/tear resistance, long shelf life, moisture resistance, and low airborne particle generation.
Foils are often used for cream or powdered pharmaceuticals when in pouch form. The provide excellent UV protection for light-sensitive products. A moisture and gas vapor barrier reduces spoiling and extends shelf life. They can be steam and radiation sterilized, and their high strength and excellent weld sealing eliminates need for adhesives.
Film can be made from a variety of polyethylene, polypropylene, polyester, and other synthetic materials. It is flexible and abrasive resistant, reducing punctures. Its transparency and light opacity ensures visual inspection of contents (conversely, offering little to no UV protection). Its anti-static properties are compatible with electronic devices, and it can be very cost-effective compared to Tyvek.
Paper is commonly used for sterilization bags and pouches for reusable devices. Highly breathable and porous, it can ensure that the sterilant can penetrate material and allow dissipation to enable proper drying. Tear resistance and smooth surfacing ensures sharp devices won’t pierce or rip material. It is extremely cost effective and easily laminated with films and hard plastics.
When working with customers designing custom pouches for their medical devices, finding the right materials and sealing techniques is often a process of elimination. The more knowledge of how the device will be used—from its sterility requirements, the expected duration of wear, prospective end-user population, and other details—the shorter the process of selecting and matching appropriate materials.