At-line Validation of Optical Coherence Tomography as In-line/At-line Coating Thickness Measurement Method

Optical Coherence Tomography (OCT) is a promising technology for monitoring of pharmaceutical coating processes.

However, the pharmaceutical development and manufacturing require a periodic validation of the sensor’s accuracy. For this purpose, we propose polyethylene terephthalate (PET) films as a model system, which can be periodically measured during manufacturing coating monitoring via OCT.

This study proposes a new approach addressing the method validation requirement in the pharmaceutical industry and presents results for complementary methods. The methods investigated include direct measurement of the layer thickness using a micrometer gauge as reference, X-ray micro computed tomography, transmission and reflectance terahertz pulsed imaging, as well as 1D- and 3D-OCT.

To quantify the significance of OCT for pharmaceutical coatings, we compared the OCT results for commercial Thrombo-ASS and Pantoloc tablets with direct measurements of coating thickness via light microscopy of microtome cuts. The results of both methods correlate very well, indicating high intra- and inter-tablet variations in the coating thickness for the commercial tablets.

The light microscopy average measured coating thickness of Thrombo-ASS (Pantoloc) was 71.0 µm (83.7 µm), with an inter-coating variability of 8.7 µm (6.5 µm) and an intra-coating variability of 2.3 µm to 9.4 µm (2.1 µm to 6.7 µm). Continue reading on OCT coating measurement

More on OSeet by Phyllon

Matthias Wolfgang, Anna Peter, Patrick Wahl, Daniel Markl, J. Axel Zeitler, Johannes G. Khinast,
At-line validation of optical coherence tomography as in-line/at-line coating thickness measurement method,
International Journal of Pharmaceutics,
Volume 572,
2019,
118766,
ISSN 0378-5173,
https://doi.org/10.1016/j.ijpharm.2019.118766.

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