The integrity of container closure systems can be interpreted as their capacity to maintain a sterile barrier against potential contaminants that could compromise the quality of the end product. The sterile barrier can be damaged by even the smallest leak, which might affect the product's healing properties. Over the years, dye ingress and microbial ingress are common leak testing methods. It has been proven that they provide inaccurate and subjective results. As a result, regulatory organizations have mandated a shift towards more deterministic test procedures that can be controlled, calibrated, and provide a definite determination of CCI. Airborne Ultrasound technology is a deterministic test method mentioned in the revised USP< 1207> Chapter Guidance for seal quality testing.
Explain Airborne Ultrasound Technology
Airborne Ultrasound Technology is a technique for testing the seal quality. It is an ASTM test method F3004 and the Food and Drug Administration (FDA) approved standard for seal quality testing. Such inspections are mainly done to provide improved seal quality inspection of pouches, flexible packages and tray seals. Airborne Ultrasound technology ensures in-depth seal quality analysis and is applicable to multiple packaging materials such as Tyvek, paper, foil, film, aluminum, plastic and poly.
In this technique, sound waves are reflected when ultrasound waves travel through the packaging seal. In the presence of a leak or fault, the signal intensity is diminished or removed. To find the leak, these fluctuations are carefully monitored. More sound is reflected, and less sound is transferred through the seal as the acoustic difference between the medium increases (most evident at the transition from a gas to solid state). The inability to detect non-leak defects is a common challenge faced by most leak test methods. However, users may recognize a variety of seal defects, including visible and invisible, leaky and non-leaking, process-related and random, using airborne ultrasound technology.
Seal-Scan and Seal-Sensor
Under this technique, VeriPac leak testers are connected to a test chamber specially designed to hold the sample package. The package that has been put inside the test chamber is subjected to vacuum. A single or dual vacuum transducer technology is used to monitor the vacuum level as well as how the vacuum changes during a predefined test period. The existence of leaks and other defects within the package is determined by monitoring variations in an absolute and differential Seal-Scan® and Seal-Sensor™ are the two configurations of Airborne Ultrasound technology. Seal-Scan® technology inspects and analyzes pouch seals non-destructively offline. This deterministic, quantitative, high resolution method inspects pouch seals for defects and seal integrity for consistency. Testing does not involve sample preparation, and is non-invasive as well. The technique includes advanced digital imaging software tools for process control that allow in-depth seal quality analysis. Utilizing Airborne Ultrasound technology, Seal-Scan® systems evaluate seal quality and integrity in accordance with ASTM Test Method F3004-13. Seal-Scan® is a semi-automatic inspection system with an x-y drive for the detection of seal defects, seal characterization, and material analysis.
Seal-Sensor™ is an Airborne Ultrasonic technology that inspects the final pouch seal 100% online in a non-destructive manner. Seal-Sensor™ is a deterministic, quantitative, fast, and reliable way to test for defects in pouch seals. The Seal-Sensor™ technology detects defective seals, seals with partial or weak areas, and several other typical seal defects that may not be physically visible but have an impact on the quality, and life span of the product. A pass/fail result and quantitative, traceable data are generated by a single linear scan (L-Scan) of the pouch seal in less than one second.
Why Use Airborne Ultrasound Technology?
- Deterministic inspection technique yielding quantifiable results.
- Non-destructive, non-subjective, and does not need sample preparation.
- Independent of color, transparency, print, surface polish, or porosity, it is applicable to all materials and combinations.
- Can be integrated completely online to identify defects in the final pouch seal.
- Consistent and dependable results.
- Referenced in USP Chapter 1207.Inexpensive method for evaluating the seal integrity of the final pouch seal.
- Describes the overall quality and uniformity of the seal.
Both Seal-Scan® and Seal-Sensor™ technologies utilize non-contact airborne ultrasonic testing technology. With the innovation of Seal Scan and Seal-Sensor, Airborne Ultrasound technology has emerged as the most reliable technique for non-destructive seal integrity testing, both in offline laboratory testing for seal quality analysis and 100% inline testing on the production line.