A TSB funded consortium of TeraView, Oystar Manesty, Liverpool University and Cambridge University have successfully demonstrated the ability to measure in-line the coating thickness distribution on a batch of tablets within a production scale coating pan in real time.
The custom developed terahertz sensor technology is rapid and can accommodate multiple coatings and layers simultaneously. In addition, the measurements require no calibration and are made on individual tablets, enabling tablet to tablet and batch to batch variability to be assessed. In contrast, existing techniques which are used in this context, such as NIR spectroscopy, require calibrating prior to each and every process, formulation or product change. Rather than providing a measurement of single tablets they measure multiple tablets and hence are unable to look at tablet-to-tablet variability within the batch during the process.
Research will now focus on investigating the role of the thickness variability during the coating process as a key quality attribute for products in which the coating thickness is directly related to their performance (e.g. controlled release products). Accessing quality based on an average thickness alone can lead to tablets being out of specification or excessively coated. Using the newly developed process sensor the team hopes that this technology can be developed into a new tool to achieve better coating quality and advance the scientific understanding of the film coating process.