X-ray tomography is a new imaging technique that offers a non-destructive method of obtaining 3-D images of microstructure. Tom Ray, RSSL, illustrates how it can be useful in product development and troubleshooting.
There are many ways in which microstructure affects the performance and characteristics of pharmaceuticals, medical devices and pharmaceutical packaging. For example, particle size and particle distribution play a part in the dissolution of tablets. The quality and thickness of a coating helps determine the stability of a capsule. Microstructure generally determines the flexibility of a plastic and hence the performance of packaging or the integrity of seals. The internal structure of a delivery device will affect how well the dose is targeted.
Similarly, given that microstructure contributes to optimum performance, micro-structural defects are often the root cause of a product’s poor performance or outright failure.
From particle sizers to powder flow analysers, from microscopes to moisture analysers there is a barrage of technology that can be brought to bear on the investigation of microstructure and/or particles within products. However, most of these methods are in some way destructive. Given the ‘closed’ nature of most pharmaceutical products, it is frequently not ideal for this to be the case. Indeed, in almost every case the ‘perfect’ analytical solution would be non-destructive, allowing the key parameters of the product to be measured in as near a natural state as possible. This is just the possibility afforded by X-ray tomography, a relatively new technology that is already proving its worth in new product development, product trouble-shooting and foreign body investigations.
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