Celebrating the Role of X-Ray Inspection

Have you ever stopped to think about how far X-ray inspection technologies have come in the pharma industry? Inspecting medicines to ensure they are free of foreign bodies is a routine feature of production lines, but the latest X-ray inspection technologies can do so much more than simply detect fragments of metal of glass in drug containers and autoinjectors. Does each section of a blister pack contain one correct, undamaged tablet, for example? Are there dangerous bubbles of air in a drug-device combination product, such as an insulin pump? Is the needle of an autoinjector in the correct position? All these questions – and more – are being answered by a new generation of inspection technology.

Anyone who relies on regular medication takes it for granted that there will be one tablet in each section of a blister pack. For pharma manufacturers, it is no mean feat to ensure there are no extra, missing, or incorrect tablets in sealed packs that pass through high-speed factory production lines. In addition, newer packaging formats may also contain multiple tablet formulations to be taken at different times. As packaging becomes increasingly complex, manufacturers must ensure their inspection technologies can keep up.

The latest X-ray systems combine low-energy X-ray imaging with active pixel sensor technology to achieve high sensitivity – with resolutions 10 times greater than traditional end-of-line X-ray machines. That means they can detect not only missing or broken tablets – with an inspection zone created around each tablet pocket – but also contaminants, even when the product is packaged in a foil blister pack. Systems also exist that can detect paper inside cardboard – which is useful for checking that box contains instructions for use/leaflets to ensure regulatory compliance.

Here are some other great examples of what today’s X-ray technologies can do. X-ray technology can be used to check the mass of a product – to ensure dose carriers for powder inhalers meet the therapeutic dose limits, for example, and that containers of common OTC medications meet the necessary weight requirements. It can also check the individual masses of a series of items within a pack – detecting and rejecting an underweight bottle of cough syrup in a multipack, for example, even if some of the other bottles contain slightly too much medication. Product number verification, such as syringes in a sealed multipack, and an elemental analysis to differentiate tablets with different formulations, to name just a few more of the novel capabilities of X-ray.

Foreign body detection has always been crucial for formulations in drug containers. The new generation of X-ray inspection equipment can detect metal or glass particles as small as 0.1 mm in diameter, which would not be visible to the naked eye on a high-speed production line. Image processing software provides the tolerance levels required to deal with the variable shape and thickness of glass containers, including tapered shapes, ridges, and bulges, as well as checking if the container is filled to the correct level.

The latest technology can also perform quality checks on drug delivery devices such as autoinjectors – ensuring the needles are in the correct position and that other parts of the device mechanism are within position tolerances. Some inline inspection machines can be automatically fed and motorized in different axes, allowing autoinjectors to be rotated for the intense quality checks. Some can also cope with the challenge of subcutaneous osmotic insulin pumps, where the drug is packaged in a hollow titanium rod and it is vital there are no bubbles, which might cause the flow of insulin to be interrupted. The radiography is challenging as it involves inspecting organic material with air voids through a machined titanium enclosure, but techniques such as mechanical stabilization and combining multiple image sets can enhance the contrast.

The technology we have access to today enables pharma manufacturers to look much closer, much further, and in much more detail than ever they could before – and I’m not just talking about AI. With millions of patients relying on their medication every day, X-ray technology has a key role to play in ensuring each dose is right first time – every time.