Dr Axel Zeitler- Terahertz Technology

http://www.scienceomega.com/article/882/terahertz-technology
Measuring through multiple coating layers without physically slicing the sample
One of the biggest challenges for the pharmaceutical industry is to manufacture tablets with consistent quality. Existing measurement technologies struggle to provide the necessary information for effective process control. Part of our research is to apply terahertz radiation to non-destructively image film coatings that are traditionally applied on tablets to change their appearance, but, more recently, have been developed to control the drug release. By exploiting the short pulse duration and the ability to penetrate most polymers, used as excipients for film coating, we are able to resolve spatially the thickness and density of the coating.

Terahertz radiation can propagate more than 3mm into the tablet and, hence, it is possible to measure through multiple coating layers without physically slicing the sample. Recently, we have developed a robust in-line system to quantitatively measure the coating thickness of randomly moving tablets. This development allows terahertz sensors to make their way from research to manufacturing control applications successfully. We are now in a position to start using the information provided by the terahertz sensor to better understand the film coating process. We hope we will be able to develop a more robust control of the process leading to safer and better products for patients.

The aim of our research in this field is to link the coating properties as measured by terahertz imaging with the performance of controlled release dosage forms. Through a better understanding of the physical properties of the film coating and the tablet dissolution, we open new opportunities for improved process understanding for applications in process analytical technology (PAT) and quality by design (QbD).

In addition to our diverse interests in pharmaceutics, we also study nanostructured materials such as carbon nanotubes (CNTs) and carbon nanofibres (CNFs) that have applications as heterogeneous catalysts as well as in many other fields. Ultimately, our goal is to relate catalytic activity and selectivity to both electronic and physical characteristics of the catalysts.

Dr Axel Zeitler
Lecturer
Terahertz Applications Group
Department of Chemical Engineering and Biotechnology
University of Cambridge
+44 (0)1223 334783
www.ceb.cam.ac.uk/thz.php


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