Ensuring package sealing integrity has long been an industry challenge, one in which the stakes are exceedingly high. Hanging in the balance are quality control standards that not only mandate pharmaceutical manufacturers’ adherence to strict guidelines and low tolerances, but also
define their incalculably priceless reputations. This is, of course, because our quality control issues are a matter of public safety rather than mere product efficacy.
The primary method being used today—sampling—only allows for a percentage of packages units to be inspected. Finally, however, technology has caught up to meet pharma’s packaging integrity inspection needs. Dynamic thermal imaging allows pharma companies to inspect 100% of packaged products in a totally passive manner without ever even having to touch them. Dynamic thermal imaging ensures that every package that leaves a facility is properly sealed, thus maintaining the necessary sealing barrier to protect product efficacy.
The science behind thermal imaging is not, in and of itself, new. As thermal imaging is so exacting, it has been used as a “see-through” technology in some of the most demanding operation environments, including the military, top-level security details, firefighting, and gas leak detection. The best-possible detection this technology affords can also be highly valuable for scientific and medical research, as well as in predictive maintenance studies for buildings and public infrastructure projects.
Until very recently, however, these technologies weren’t cost-effective enough to be considered commercially viable. The pharma industry marks one of thermal imaging’s first forays into the global marketplace, with companies such as Pfizer and others currently participating in trial runs on select production lines.
How dynamic thermal imaging works
Thermal Imaging is an infrared imaging science that detects the naturally emitted radiation in the infrared range of the electromagnetic spectrum (roughly 3,000– 14,000 nanometers or 3–14 μm), then translates this radiation data into images called thermograms. Because infrared radiation is emitted by all objects above absolute zero, thermal imaging makes it possible to examine products in an environment without physical contact or visible illumination.
The amount of radiation emitted by an object increases with temperature; therefore, thermal imaging reveals variations or irregularities in temperature. At the height of its precision, thermal imaging can detect changes in temperature so slight—as small as 0.02°C—that they were previously undetectable or, in the case of commercial ventures, not economically viable. Thanks primarily to improved cost-effectiveness in producing a new generation of lower cost/higher sensitivity cooled and uncooled detectors, however, this has changed—and the resulting enhanced level of inspection has the potential to overhaul and upgrade package inspection practices throughout the pharmaceutical, nutraceutical, and medical device industries.
Benefits and applications
Dynamic thermal imaging is a convenient and accurate tool for package integrity and fill level monitoring. By detecting the amount of radiation emitted by objects, dynamic thermal imaging makes it possible to examine an environment without touching or even illuminating an object.
Thermal imaging offers real-time testing of 100% of the products on a line, real-time process monitoring, full records (including photos) for every product, and very high throughput with no production slowdown…all in a non-destructive, non-interfering fashion. In a recent application for induction sealed bottle cap liners, speeds of 400 bottles/minute were achieved. In sachet and pouch seal and fill monitoring, multi-lane format applications can yield even higher speeds.
This combination of precision and non-invasiveness makes thermal imaging suited for seal verification of plastic bottles and virtually any kind of flexible packaging such as sachets, pouches, stick packs, blisters, etc. It also can be used for tablet and liquid fill level inspection, as well as desiccant count/inspection. In short, dynamic thermal imaging can be used to inspect a wide variety of package types.
Added to this versatility is portability. Thermal imaging units can offer wheel-up/wheel-away convenience that makes it transferrable from one packaging line to another in minutes, thus making the application valuable to CPOs wishing to vary which production lines require 100% inspection—a decision typically based on the needs of individual clients.
Inspecting sealed bottles through caps
DIR Technologies, a spin-off of SemiConductor Devices (SCD), has filed several thermal imaging patents for the in-line monitoring of the seal integrity of induction sealed cap liners in bottles and seal integrity and fill volumes of sachets. One such system tests inline the seal integrity
of induction-sealed cap liners on bottles. It is capable of inspecting 100 percent of the bottles undergoing induction sealing in a totally passive way, with a small footprint, and without necessitating any format parts. The process is completely validatable, CFR 21 Part 11 compliant, and, for serialization applications, can assign a 2D thermographic image of a specific bottle’s seal integrity verification. Inspection is performed through the cap by means of high-sensitivity thermal imaging. Upon being detected any defective bottles are removed from the production line. The system can measure most bottle and cap sizes and types.
For an industry with high quality control requirements, sampling has become increasingly insufficient. Camera systems utilizing even extremely high sensitivity color cameras can perceive faults only in the relatively narrow visible spectrum.
Dynamic thermal imaging is a powerful new technology that has the potential to bring a paradigm change to in-line quality control by replacing package sampling with continuous, non-invasive process verification that ensures the safety and integrity of pharmaceutical packaging.
Bob Hartwig, Managing Director of BTS International, is the North American representative for DIR Technologies, which develops solutions for pharmaceutical product authentication, manufacturing, and packaging process control. In addition to the thermal imaging capabilities, DIR Technologies specializes in image processing, machine vision, and real-time data processing. www.dir-technologies.com
This article appeared in the January/February 2015 issue of Controlled Environments.