When it comes to medical packaging, sterility and product protection don’t end once a device leaves the cleanroom. Packaging must continue to safeguard the product throughout sterilization, shipping, and storage — sometimes for years. Barrier properties are central to this performance, determining how well a package protects against moisture, oxygen, and other environmental factors that can compromise product safety and shelf life, and it is crucial to understand the right barrier level required for each application.
A barrier packaging guide can help manufacturers select the appropriate barrier level for different products, ensuring optimal protection and shelf life.
To protect against environmental factors, packaging materials utilize various types of barriers, such as those that block gases, moisture, light, and odors. The use of high barrier materials, especially multilayer films and coatings, is essential for extending shelf life and maintaining product freshness by providing superior protection against oxygen and moisture.
The effectiveness of these barriers is barrier measured using industry-standard tests like moisture vapor transmission rate (MVTR) and oxygen transmission rate (OTR).
Why Barrier Properties Matter
Medical devices and pharmaceuticals are highly sensitive to their environment. Excess moisture can corrode instruments or interfere with drug formulations, while oxygen exposure can degrade active ingredients or materials. Barrier packaging also protects against the transmission of molecular gas and organic solvents, which can compromise product integrity. Without the right barrier properties, even sterile products can become unsafe before they reach the patient. An effective aroma barrier is also important for products sensitive to odors, as it prevents the escape or ingress of scents and helps maintain product freshness. That’s why engineers pay close attention to oxygen transmission rate (OTR) and moisture vapor transmission rate (MVTR) when evaluating packaging resins.
Barrier properties are critical for patient safety, as compromised packaging can lead to contamination or reduced efficacy of medications. Proper packaging and labeling solutions help reduce medication errors, thereby improving patient safety and ensuring patient safety throughout the supply chain. Effective packaging also supports medication management and can positively impact patient outcomes.
Material Choices and Tradeoffs
Different plastics offer different levels of protection. PETG provides excellent clarity and toughness, but it has moderate moisture barrier performance. APET, a form of polyethylene terephthalate, improves moisture resistance but can be brittle, limiting its use in certain rigid tray applications. Polyethylene terephthalate is a key material in barrier packaging due to its effective protection against gases, moisture, and aromas.
Plastic film and plastic films are widely used in barrier packaging, providing varying degrees of protection against oxygen, moisture, and light. Polypropylene, especially in advanced formulations, offers strong moisture resistance, good oxygen barrier properties, and heat stability, making it increasingly popular for rigid medical packaging. On the other hand, polyethylene provides flexibility and toughness but may not deliver the transparency required for some applications. Coated films and laminated packaging are advanced material options that further enhance barrier protection by combining different polymers and coatings.
Barrier packaging often utilizes multiple layers, such as two layers or even more, to improve protective qualities. A double layer or double layer barrier structure, often with a specialized middle layer, can significantly enhance resistance to moisture, gases, and aromas. These multilayer constructions are common in flexible packaging, stand-up pouches, and gusset bags.
When choosing materials, single layer barriers offer basic protection and are suitable for general packaging needs, but multilayer options provide enhanced performance. The trade-off is that multilayer barriers, while offering higher protection, may come at increased cost and complexity. Metallized films are a high barrier option, especially effective for protecting against oxygen, light, and moisture.
Barrier materials can be categorized as moderate barrier, higher barrier, or high performing barrier, depending on their ability to block gases, moisture, aromas, and light. High performing barrier materials, such as those with metallized films or aluminum layers, are used for sensitive products like perishable products, food, and pet treats. Moisture barrier properties are crucial for maintaining product freshness and extending shelf life.
Food safe materials, such as PET and PP, are essential for packaging edible products, ensuring compliance with safety standards. Blocking visible light, UV light, and sometimes UV light is important for protecting products from degradation and spoilage. Plastic bags are also commonly used in barrier packaging for their convenience and basic protective qualities.
Each material and structure offers specific advantages, such as improved shelf life, product protection, and suitability for different applications. Basic barrier and basic barriers provide entry-level protection, while more advanced options offer greater performance. There are four categories of barrier protection, ranging from basic to high performing, determined by the permeability of the films.
Flexible packaging plays a significant role in barrier protection, offering versatility for various product types. Specialized applications, such as unit dose medication packaging and medical device packaging, require tailored barrier solutions to ensure safety and compliance. Packaging solutions serve different market segments, including healthcare, pharmaceutical, and food industries, each with unique requirements.
For food packaging, especially for perishable products, selecting the appropriate barrier is essential to maintain freshness and prevent spoilage. Auto print technology is increasingly used in packaging and labeling solutions to improve efficiency and accuracy in various market applications.
Each material brings a balance of clarity, barrier, and processability — and the right choice depends on the device’s requirements.
Measuring Barrier Properties
Accurately measuring barrier properties is an essential part of developing effective packaging solutions for pharmaceutical packaging, medical packaging, and food packaging. Barrier properties determine how well a material can prevent the passage of moisture, oxygen, and other gases—factors that directly impact the quality and safety of packaged goods. In healthcare and food industries, even small amounts of moisture or oxygen can compromise sensitive products, making reliable barrier protection a top priority.
To assess a material’s performance, specialized tests are used to measure how much moisture or gas can pass through packaging under controlled conditions. These tests, such as water vapor transmission rate (WVTR) and oxygen transmission rate (OTR), provide quantifiable data on a material’s barrier strength. By understanding these values, manufacturers can select the right materials to meet the specific needs of their products, whether it’s extending shelf life for food products or ensuring the sterility of medical devices.
Consistent measurement of barrier properties is crucial for maintaining high standards in pharmaceutical packaging and food packaging. It helps ensure that every package delivers the necessary protection, supporting both product quality and patient safety. As packaging materials and technologies evolve, ongoing testing and validation remain essential to meet regulatory requirements and the expectations of healthcare providers and consumers alike.
Designing for Shelf Life and Sterility
Barrier properties aren’t just about passing tests — they directly influence shelf life and regulatory compliance. Maintaining optimal moisture barrier properties and the appropriate barrier level throughout the product’s intended lifespan is critical to ensure product quality and safety. A package that loses barrier integrity before its intended expiration date risks product recalls, wasted inventory, and, most importantly, patient safety. That’s why many engineers conduct accelerated aging studies to validate performance over time and under various environmental conditions, with barrier measured using metrics such as moisture vapor transmission rate (MVTR) and oxygen transmission rate (OTR).
Balancing Barrier with Sustainability
As sustainability becomes a higher priority in healthcare packaging, engineers face the added challenge of meeting barrier requirements without compromising recyclability. Mono-material structures, particularly those based on polypropylene, are emerging as a promising way to balance both needs. By reducing reliance on multi-material laminates, packaging designers can maintain sterility and shelf life while improving recyclability under evolving EPR frameworks.
Final Thoughts
Barrier properties may be invisible, but their impact on medical packaging is anything but. From protecting sterility and extending shelf life to ensuring regulatory compliance, barrier performance is one of the most critical factors in material selection. With thoughtful design and the right resin, it’s possible to achieve a balance between safety, performance, and sustainability.
At Impact Plastics, we help our healthcare partners evaluate barrier properties alongside clarity, sterilization compatibility, and recyclability — so they can make informed choices that protect patients and align with the industry’s future.