A quantitative comparison of in-line coating thickness distributions obtained from a pharmaceutical tablet mixing process using discrete element method and terahertz pulsed imaging

Pei, Chunlei and Lin, Hungyen and Markl, Daniel and Shen, Yao-Chun and Zeitler, J. Axel and Elliott, James A. (2018) A quantitative comparison of in-line coating thickness distributions obtained from a pharmaceutical tablet mixing process using discrete element method and terahertz pulsed imaging. Chemical Engineering Science, 192. pp. 34-45. ISSN 0009-2509

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    Abstract

    The application of terahertz pulsed imaging (TPI) in an in-line configuration to monitor the coating thickness distribution of pharmaceutical tablets has the potential to improve the performance and quality of the spray coating process. In this study, an in-line TPI method is used to measure coating thickness distributions on pre-coated tablets during mixing in a rotating pan, and compared with results obtained numerically using the discrete element method (DEM) combined with a ray-tracing technique. The hit rates (i.e. the number of successful coating thickness measurements per minute) obtained from both terahertz in-line experiments and the DEM/ray-tracing simulations are in good agreement, and both increase with the number of baffles in the mixing pan. We demonstrate that the coating thickness variability as determined from the ray-traced data and the terahertz in-line measurements represents mainly the intra-tablet variability due to relatively uniform mean coating thickness across tablets. The mean coating thickness of the ray-traced data from the numerical simulations agrees well with the mean coating thickness as determined by the off-line TPI measurements. The mean coating thickness of in-line TPI measurements is slightly higher than that of the off-line measurements. This discrepancy can be corrected based on the cap-to-band surface area ratio of the tablet and the cap-to-band sampling ratio obtained from ray-tracing simulations: the corrected mean coating thickness of the in-line TPI measurements shows a better agreement with that of the off-line measurements.

    Author(s):Pei, Chunlei, Lin, Hungyen, Markl, Daniel ORCID logoORCID: https://orcid.org/0000-0003-0411-733X, Shen, Yao-Chun, Zeitler, J. Axel and Elliott, James A.
    Item type:Article
    ID code:68879
    Keywords:coating thickness variability, discrete element method, pharmaceutical coating, Terahertz in-line sensing, Terahertz pulsed imaging, Chemical engineering, Therapeutics. Pharmacology, Chemical Engineering(all), Industrial and Manufacturing Engineering
    Subjects:Technology > Chemical engineering
    Medicine > Therapeutics. Pharmacology
    Department:Faculty of Science > Strathclyde Institute of Pharmacy and Biomedical Sciences
    Depositing user: Pure Administrator
    Date deposited:17 Jul 2019 10:39
    Last modified:08 Nov 2019 06:44
    URI:https://strathprints.strath.ac.uk/id/eprint/68879
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