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Flexible packaging has become increasingly popular in various industries due to its versatility and cost-effectiveness. It is used for packaging a wide range of products, including food, pharmaceuticals, electronics, and more. It includes materials like pouches, bags, sachets, and wraps made from materials such as plastic, foil, paper, and laminates. Flexible packaging offers several advantages, such as being lightweight, space-efficient, and customizable in terms of design.

Flexible package seal integrity testing is of paramount importance due to its direct impact on product quality, safety, and consumer satisfaction. A secure and intact seal serves as the primary defense against external factors that could compromise the contents of the packaging. This includes preventing the ingress of moisture, oxygen, and other contaminants, all of which can adversely affect the product's shelf life, flavor, texture, and overall quality. A compromised seal not only risks the product's integrity but also raises concerns related to food safety and hygiene. In industries such as food and pharmaceuticals, maintaining seal integrity is vital to prevent potential health hazards and economic losses.

Furthermore, a strong focus on flexible package seal integrity testing is crucial for businesses aiming to uphold their brand reputation and avoid costly recalls. Products with compromised seals could lead to customer dissatisfaction. By implementing rigorous seal integrity testing protocols, manufacturers can ensure that their products remain fresh, safe, and free from contaminants, thereby safeguarding their brand's image and preserving customer loyalty.

Package seal quality inspection using Airborne Ultrasound Technology

PTI's Airborne ultrasound technology is a non-destructive, non-invasive method for seal integrity testing of flexible packages. It is a deterministic, quantitative test method and also an ASTM Test Method F3004-13. It is based on the principle that ultrasound waves are reflected at different rates depending on the density of the material they are traveling through. When ultrasound waves are transmitted through a package seal, any defects in the seal will cause the signal waves to be reflected differently, resulting in a change in the signal strength.

Airborne ultrasound technology is a versatile and reliable method for testing seals on a wide variety of flexible packaging materials, including films, foils, laminates, and pouches. It is also capable of testing seals on a variety of product types, including food and beverage products, pharmaceutical products, and medical device products.

PTI offers two configurations of Airborne ultrasound testing technology: Seal-Scan and Seal-Sensor. Seal-Scan is a high-resolution method that inspects and analyzes pouch seals non-destructively offline. Seal-Sensor is designed for 100% online pouch seal inspection.

Benefits of Airborne Ultrasound Technology

• Non-destructive and non-invasive
• Deterministic, quantitative test results
• ASTM Test Method F3004-13 compliant
• Capable of testing a wide range of flexible packaging materials
• Detects a variety of seal defects, including leaks, misaligned seals, incomplete seals, missing seals, channel defects, pin holes, and porosity
• High-speed inspection capabilities
• Easy to integrate into production lines

The science behind perfecting flexible package seal integrity is a multidimensional approach that combines technological advancements with a commitment to product quality, safety, and brand reputation. Airborne ultrasound technology is just one example of how innovative methods are used to ensure that the seals on flexible packages remain strong, secure, and reliable.

Package integrity leak test methods offered by CCIT such as Seal-Scan utilize non-contact Airborne Ultrasonic technology for seal integrity testing and seal quality analysis of pouches and flexible packaging. The method is applicable to pharmaceutical as well as medical device packaging.

Seal Quality Testing and Seal Analysis using Seal-Scan Technology

Seal-Scan® is a non-destructive offline inspection and analysis technique for pouch seals using Airborne Ultrasonic technology (ABUS). Seal-Scan® offers advanced digital imaging software tools for process control, including in-depth seal quality inspection. Seal-Scan system uses the non-destructive ASTM Test Method F3004-13 for "Evaluation of Seal Quality and Integrity Using Airborne Ultrasound Technology." This test method was approved using PTI's ABUS technology. Seal-Scan® is a deterministic, quantitative, high-resolution technology for inspecting pouch seals for defects and ensuring seal integrity.

Seal-Scan has two scanning modes:

• Linear Scan (L-Scan) to simulate online defect identification (line graph)
• C-Scan for detailed seal analysis, resulting in pixel-by-pixel seal evaluation (Opto-Acoustic image)

Technology Overview

The pouch seal or packaging material is scanned between two focused ultrasonic sensors. Ultrasonic waves travel through single or several layers of bonded materials. The reflection of sound waves caused by ultrasonic transmission via different materials reduces/eliminates signal intensity. The signal level that passes through the seal is a function of the seal's quality. Defects of various forms, such as leaking and non-leaking, process-related and random, can be detected. Seal-Scan® can provide Opto-Acoustic images as well as thorough statistical analysis using one of two scan modes (L-Scan and C-Scan).

An L-Scan is a single linear scan along the seal's X-axis that generates a line graph of seal integrity and replicates real-time inspection. C-Scan generates a series of scans (along the X and Y-axis of the seal region), that offers a high-resolution ultrasonic image of the seal structure. This technology, via the Seal-Sensor, can be integrated into a pouch production process for 100% online seal defect detection.

Benefits of Seal-Scan Technology

• Deterministic inspection approach yielding quantitative results.
• Works with any material and combination, independent of color, transparency, print, surface polish, or porosity.
• Produces a high-resolution Opto-Acoustic seal image.
• Characterizes the overall quality and consistency of the seal.

Seal-Scan® is a semi-automatic inspection system with an x-y drive that is used to identify seal defects, characterize seals, and analyze materials. This approach is non-invasive, non-destructive, and does not need any sample preparation. The ability of PTI to adapt this technology to diverse production restrictions and conditions makes it an effective solution for flexible packaging systems.

Testing the integrity of package seals helps ensure that nutritional packaging provides required product protection. Maintaining the reliability of package seals is critical for product quality and food safety. Airborne Ultrasound and Vacuum Decay technology can be used for testing package and seal integrity of nutritional packages. These CCI technologies produce quantitative, and repeatable results, due to their deterministic nature. The primary purpose of implementing these testing methods is to ensure the safety of consumers.

Overview of Nutritional Packaging Inspection

Nutritional packaging plays a significant role in securely delivering the product. The majority of nutritional products are shelf-stable in nature, therefore package performance is typically a concern. Chemical reactions occur naturally in all nutritional products. Any break in the nutritional packing might lead to the products deteriorating due to air, moisture, and microbial exposure. Fats and other nutrients for infants might become rancid and inactive. The quality and safety of the contents that reach the customer are determined by nutritional packaging.

Package and seal integrity techniques have great expertise in the packaging industry, which helps in inspecting nutritional packages in the most efficient method in order to preserve package and product quality. For the food and nutritional packaging industries, CCIT provides a variety of technologies and solutions. The two most common nutritional package inspection technologies are vacuum decay and airborne ultrasound. While vacuum decay is utilized for applications such as filled and sealed rigid containers, dry products in pouches, and flexible packaging. Retort pouch final seal inspection can be achieved using non-destructive with airborne ultrasound technology.

Technologies to Assure Package and Seal Integrity

Vacuum Decay Technology

Vacuum decay is a package test method for vacuum-based leak detection. It is considered one of the most practical and sensitive test methods used in nutritional package inspection. When compared to destructive test procedures, this technology not only provides for a better understanding of package quality but also minimizes waste. As a result of the waste reduction, the return on investment is higher, and the operation is closer to green initiatives.

The Vacuum Decay leak testing method operates by enclosing package samples in an evacuation test chamber with an external vacuum source. The test chamber is monitored for both the level of vacuum and the change in vacuum during a pre-defined test duration using single or dual vacuum transducer technology. The existence of leaks and defects within the package is indicated by variations in an absolute and differential vacuum. Test systems can be designed to be operated manually or fully automated.

Airborne Ultrasound Technology

Pouches are the common form of packaging for most nutritional products. Hence, it is necessary to ensure the package integrity of such pouches. Airborne Ultrasound is a non-destructive and non-invasive method of inspecting seal quality. In this method, ultrasound waves are permitted to pass through the package seal, causing sound waves to be reflected. The fluctuation in the reflected signal intensity is used to detect defects.

Airborne Ultrasound technology is available in both online and offline solution options. It has been proven to be one of the most successful non-destructive testing procedures for flexible package seals. According to ASTM F3004-13, this is the standard test technique for evaluating seal quality and integrity using airborne ultrasound. This method has high applicability in the food and nutrition industry.

Vacuum Decay technology and Airborne Ultrasound technology are both ASTM test methods and also FDA consensus standards for package integrity and seal quality inspection of nutritional products. An appropriate testing method for inspecting nutritional packages is selected based on the nature of the product and its package.

Sterile pharmaceutical products including vials are manufactured with extreme accuracy and zero tolerance for error. As a result, pharmaceutical manufacturers place a high value on their quality control procedures. This is to guarantee that the items meet the quality requirements for their intended application. Packaging is essential for maintaining product quality and providing protection from harmful external forces. Package integrity testing, in addition to selecting suitable packing material, is a crucial component in preserving product quality. It prevents external contamination that can have a negative influence on drug quality by ensuring that there are no leaks within the package.

An effective package integrity solution for vials will ensure:

• The vial is well-protected from external factors that might affect its quality, such as light, oxygen, moisture, and temperature
• It is safe from contamination

Various Container closure integrity testing (CCIT) technologies are available today. Helium leak detection is one of the leading methods used for testing the container closure integrity of vials.

Helium Leak Detection Technology for CCI testing of Vials

The process of detecting leaks in various enclosed or sealed systems by utilizing helium as a tracer gas and measuring its concentration as it leaves due to leakage is termed Helium leak testing. Simply say, a vial that consists of a container and an elastomeric closure is a good example for package system. The vial is filled with helium and evacuated. The quantity of helium that escapes from the package is quantified and expressed as a leak rate. A prefilled syringe, a foil pouch, or a cold form blister card are another example. Each of these package types is meant to keep the pharmaceutical product enclosed while keeping out potentially harmful environmental pollutants like germs, or even gases.

Helium gas has a number of qualities that make it the best choice for package leak testing

• As helium gas is one of the smallest molecules, it may reliably and rapidly breach pathways.
• It is an inert gas that won't react with the components being tested, therefore it's perfectly safe to use.
• Because of its limited presence in the atmosphere (less than 5ppm), instrument noise from atmospheric helium is intrinsically minimal, resulting in very precise findings.

Following are the advantages of using helium leak detection technology for CCI testing

• Highly sensitive leak test method for CCI
• Specially designed for detecting extremely small leaks that other leak test methods failed to detect.
• The leak test thresholds might be adjusted as low as 1 x 10 -10 cc/s using a high vacuum technique. This allows unique comparison amongst package components.

Sterility of vials is essential for reducing and preventing infection in patients when using the medicine. As a result, package integrity testing is essential for regulatory approval of sterile pharmaceutical products, and medical devices. When it comes to package integrity testing of vials, the terms packaging integrity and container-closure integrity are sometimes used interchangeably.

At CCIT, we provide a wide range of quality leak testing equipment for pharmaceuticals including vials. With our high-grade non-destructive testing equipment, you can ensure that your products meet stringent quality requirements.

Prior to commercialization, the development of new pharmaceuticals, particularly combination treatments, was a complicated process involving extensive research. When it comes to packing pharmaceuticals for patient use, several things must be considered to ensure that they satisfy the highest quality requirements and are safe to use.

Nowadays, the challenge of adopting traditional glass or specialized polymers as combination products has become common. Similarly, the demand for scientific evidence to support regulatory requirements for the pharmaceutical industry has also become more prevalent. For effective development and commercialization of a pharmaceutical product, it is important to understand the compatibility and performance of the primary packaging system with both, the pharmaceutical product and the delivery systems, regardless of the material.

Container Closure Integrity (CCI)

Container closure integrity (CCI) testing is important when ensuring the quality of all packaged products, especially when it comes to parenteral drugs. To evaluate the CCI of the packaging system, a pharmaceutical manufacturer must calculate the Maximum Allowable Leakage Limit (MALL) for the pharmaceutical product. MALL is defined by USP<1207> Package Integrity Evaluation – Sterile Products as the highest leak rate that may be tolerated for a specific packaging method while posing no harm to the safety and quality of the pharmaceutical product over its shelf life. In comparison to probabilistic approaches, USP <1207> provides guidelines on how to assess CCI, including deterministic methods, which are strongly encouraged. Helium leak detection, MicroCurrent HVLD, and Vacuum decay- are deterministic techniques. For the given system, these techniques must be created and validated.

Test methods

MicroCurrent HVLD

MicroCurrent HVLD is a non-destructive technique for determining the integrity of container closures for a variety of parenteral liquid products, including ultra-low conductivity sterile water for injection (WFI). A non-conductive container is examined for pinholes, micro-cracks, plunger leakage, and non-visible crimping leaks, among other things, using an electrode probe. Whenever a defect is identified, it causes a change in current flow and resistance differential, which indicates a breach in the container. The MicroCurrent HVLD is a High Voltage Leak Detection method effective across all parenteral products.

Helium Leak Detection

Helium leak detection is a deterministic method used to detect leaks in pressure vessels and other enclosed systems. In this technique, helium is used as a tracer gas. The change in helium concentration as it escapes through the container is monitored. For helium-based leak detection systems, the Seal Integrity Monitoring System (SIMS) 1915+ is a perfect choice. Helium as a tracer gas delivers excellent levels of quantitative accuracy when compared to traditional vacuum bubble and dye penetration test techniques. Helium is an optimal solution for product quality monitoring across the product lifecycle.

Vacuum Decay

A non-destructive CCI test method for evaluating medical device package integrity. Non-destructive testing improves package quality while decreasing waste when compared to destructive testing. This testing also saves time and money while ensuring product quality. This method operates by enclosing sample packages in a tight-fitting evacuation test chamber with an external vacuum source. A single or dual vacuum transducer is utilized in the test chamber to measure the level of vacuum as well as the change in vacuum over a pre-defined time period. The existence of leaks and defects is indicated by fluctuations in the package's absolute and differential vacuum.

Regardless of the pharmaceutical product, type of materials, devices used, developing a complete testing plan from initial compatibility to stability and release is critical. To assure the availability of scientific data that helps ensure optimal results for patients as well as rapid regulatory approval and delivery to the market, proper testing is required.

Airborne Ultrasound is a deterministic test method for seal quality inspection and analysis of material types such as aluminum, foil, paper, plastic, poly, film & Tyvek. In accordance with ASTM F3004-13, airborne ultrasound is a standard test technique for evaluating seal quality and integrity. It has been proven to be one of the most successful non-destructive testing methods for flexible package seals. As per research the standard seal inspection methods are inaccurate because they fail to detect invisible defects and mistakenly reject well sealed pouches. Airborne Ultrasound technology, on the other hand, has been proven in the field of both online and offline solution options

How does Airborne Ultrasound Technology mitigate the risk of food and nutrition packaging?

Packaging has been an integral part of food and nutrition preservation in recent decades. Food is packaged with the intention of being transported and stored. Quality, brand, safety, and value of a product are all affected by packaging. To ensure the safety of their products, food producers pack their products in a way that ensures they are correctly constructed, tamper-proof, defect-free, and complete.

In Airborne Ultrasound technology, sound waves are reflected when ultrasound waves are allowed to travel through the packaging seal. Change in the intensity of the reflected signal is used to identify defects. The seal is positioned in a straight line between a pair of transducers, then moves them along the seal. Transmission and reflection of the ultrasound occur at the transition from one medium to another. When the difference in acoustic properties between two materials is greater, only less sound is transmitted, and more sound is reflected. Thickness variations have a minor impact. It is possible to identify a wide range of defects, including those that are visible and invisible, leaking and non-leaking, process-related and random.

As one of the most successful methods for non-destructive testing of flexible packaging, Airborne Ultrasound technology was awarded the ASTM Test Method F3004-13 in 2013. The flow of gas or liquid through the seal is an example of seal defect. Inability to discover non-leak defects is a basic problem with leak testing methods. However, Airborne Ultrasound technology gives a complete way to evaluating seal quality, even when a seal has a defect but may not leak.

Key benefits of Airborne Ultrasound Technology

• Deterministic inspection technique resulting in quantitative results
• Non-destructive, non-subjective, zero sample preparations
• Detects defects in the final pouch seal in real time
• This method works with any material and combination, regardless of color, porosity, surface finish, transparency, and print
• The subjective manual vision inspection procedures are no longer necessary
• Results are repeatable and reliable
• Testing the final pouch seal integrity at a low cost
• Characterizes the seal's overall quality and consistency

What is Container Closure Integrity Testing?

Container Closure Integrity Testing can be understood as a leak detection test conducted using non-destructive package inspection systems to ensure product stability throughout its shelf life. CCIT plays a major part in ensuring that the products are free from possible contamination. While there are multiple ways to conduct a CCI test, it can be broadly classified into probabilistic and deterministic test methods. Traditional test methods like bubble test, dye ingress and microbial challenge by immersion come under probabilistic test methods. However, upon realizing that such tests lacked accuracy and reliability, The United States Pharmacopeia released guidelines in 2016 stating that deterministic methods ae preferred over probabilistic test methods. Vacuum Decay technology and Airborne Ultrasound technology are among the most preferred deterministic test methods.

VeriPac Test Systems for Effective CCI Testing

The VeriPac test methods are non-destructive, non-invasive inspection system for CCI and package integrity testing. They utilize the ASTM approved patented vacuum decay leak test method recognized by the FDA as a consensus standard for package integrity testing.

This ASTM method was developed using VeriPac leak test instruments and has proven its capabilities under GMP regulatory guidelines. Applications for VeriPac technology include stability studies, clinical trials, quality assurance testing and statistical process control (SPC). VeriPac testers feature the patented PERMA-Vac manifold system and dynamic test modes that provide the ability to test a wide range of package formats. Leak detection of high-risk applications requires the highest level of test measurement reliability. The VeriPac series have redefined the reliability and accuracy of test measurement systems.

How do Veripac Test systems Operate?

VeriPac leak testers connect to a test chamber that is specially designed to contain the package to be tested. The package is placed inside the test chamber to which vacuum is applied. The single or dual vacuum transducer technology is used to monitor the test chamber for both the level of vacuum as well as the change in vacuum over a predetermined test time. The changes in absolute and differential vacuum indicate the presence of leaks and defects within the package. Test systems can be designed for manual or automatic operation. This inspection method is suitable for laboratory offline testing and production applications for QA/QC statistical process control. The test cycle takes only a few seconds, is non-invasive and non-destructive to both product and package, making it an ideal choice for CCI inspection across industries.

Inspection Criteria

• Seal quality testing of entire container or package
• Measures and verifies container closure system integrity
• Tests for gas leaks for dry products (lyophilized vials, powder filled)
• Tests for liquid leaks (liquid filled vials, pre-filled syringes)

Talking about medical devices, ensuring seal quality or seal strength of sterile medical device packaging are extremely crucial as well as highly regulated. Medical device package seal contains a flexible barrier which is joined to the rigid container through an advanced adhesive. A defect in the seal such as an incomplete or weak seal can initiate leaks, contaminating the product and reducing its shelf life. Hence, for quality control purposes, seal quality inspection of medical device packages is mandatory.

Historically, manual inspection was the most popular method used to inspect seal defects. Although this is covered by an ASTM method (ASTM F1886), it lacked accuracy and reliability in terms of test results. “There is a huge shift in the industry towards deterministic and quantitative test methods,” comments Oliver Stauffer, Chief Executive Officer at PTI - Packaging Technologies & Inspection. “This includes Vacuum Decay and Airborne Ultrasound for medical device applications. The industry is currently moving away from dye ingress and manual visual inspection because there are so many blind spots in applying them and there’s a huge false sense of assurance.”

Airborne Ultrasound technology is a non-destructive seal integrity test method capable of advanced seal quality inspection of pouches and flexible packaging. Seal defects can be of two types- leak defects and non- leak defects. While it is easier to detect a leak defect, detecting non-leak defects can be a challenge for manufacturers. However, Airborne Ultrasound technology allows non-destructive Container Closure Integrity testing of multiple seal defects including visible and invisible, leaking and non-leaking, process-related and random- making it a practical solution for medical device seal quality inspection.

Technology overview

Airborne Ultrasound technology utilizes ultrasound waves to detect defects in package seals. Ultrasound waves are passed through the material as the package seal moves along the sensor head. This causes reflections of sound waves. In the presence of a leak, the signal strength is either eliminated or reduced. Such variations in signal strength are analyzed to identify the defects. Seal scan testing is a practical solution to recognize defects, such as inconsistent seals or areas of seals that fail to meet minimum width requirement. Seal-Scan® and Seal-Sensor utilize non-contact airborne ultrasonic testing technology for advanced seal quality inspection. Seal-Scan® technology has been proven in the field by several online and offline units installed.

Benefits of Airborne Ultrasound technology

• Deterministic seal quality inspection method that produces quantitative results.
• This method works for any material type and combinations regardless of color, transparency, print, surface finish or porosity.  
• Non-destructive and non-subjective test method that requires no sample preparation.
• Technology can be integrated for 100% online defect detection of the final pouch seal.
• Repeatable, reproducible and reliable results for seal quality inspection.
• Cost-effective solution for seal integrity testing and seal analysis that characterizes overall quality and uniformity of the seal. 

Medical device quality control inspection is considered to be highly significant in ensuring safe delivery of medical devices from their place of origin to the market. However, tremendous development in medical technologies have challenged the medical device packaging industry to ensure quality and reliability in packaging

Adding to that, drug contamination is a serious concern in any medical industry- specifically for Class III medical devices. Class III medical devices are understood as devices that sustain or support life and are implanted, or present potential unreasonable risk of illness or injury. Since these devices are directly placed into human bodies, proper packaging is required to ensure quality of the product until it reaches the patient. Any breach in the packaging can cause contaminants to enter the device, causing major health risks. Hence, appropriate package integrity testing and seal quality inspection of Class III medical devices are required so as to ensure seal quality and sterile barrier integrity are maintained.

Initially, manufacturers heavily relied on visual inspection or other probabilistic test methods to inspect seal quality and integrity. However, such methods lacked accuracy and reliability in terms of test results. Hence, manufacturers are now shifting towards non-destructive method for evaluating seal quality and inspecting physical properties of a seal. One such technique that is increasingly becoming popular among medical device manufacturers is Airborne Ultrasound technology. It is an ASTM test method F3004 and FDA recognized standard for seal quality integrity testing. These tests are primarily conducted to provide advanced seal quality inspection of pouches, flexible packages and tray seals. The test is conducted by transmitting high frequency sound waves through the pouch seal area, providing a simple pass or fail result of seal quality. A linear scan analysis of the seal area will detect channel defects, misaligned seals, incomplete and missing seals immediately after the package has been sealed. If the system detects a package defect, the product can immediately be removed from the packaging and reworked. Process related defects can also be addressed and corrected immediately, which significantly reduces the quantity of defective packages produced

Airborne Ultrasound technology variants, namely Seal-Scan® and Seal-Sensor provide both, offline and online inspection of packages and accommodate various package specifications, test sensitivity and package handling requirements. Seal-Scan® offline systems offer in-depth seal quality analysis and seal characterization. Seal-Sensor online inspection systems for automated 100% inline scanning of pouch seals can be integrated into pouch production or pouch handling line. They provide a quick analysis of the seal area without tampering with the packaging to identify defects, such as incomplete or missing seals, wrinkles, channel defects and so on.

Advantages of Seal Scan and Seal Sensor method

• Deterministic seal quality inspection method that produces quantitative results.
• This method works for any material type and combinations regardless of color, transparency, print, surface finish or porosity.
• Non-destructive and non-subjective test method that requires no sample preparation.
• Technology can be integrated for 100% online defect detection of the final pouch seal.
• Repeatable, reproducible and reliable results for seal quality inspection.
• Cost-effective solution for seal integrity testing and seal analysis that characterizes overall quality and uniformity of the seal.