Design of experiments to study the impact of process parameters on droplet size and development of non-invasive imaging techniques in tablet coating


Atomisation of an aqueous solution for tablet film coating is a complex process with multiple factors determining droplet formation and properties. The importance of droplet size for an efficient process and a high quality final product has been noted in the literature, with smaller droplets reported to produce smoother, more homogenous coatings whilst simultaneously avoiding the risk of damage through over-wetting of the tablet core. In this work the effect of droplet size on tablet film coat characteristics was investigated using X-ray microcomputed tomography (XμCT) and confocal laser scanning microscopy (CLSM). A quality by design approach utilising design of experiments (DOE) was used to optimise the conditions necessary for production of droplets at a small (20 μm) and large (70 μm) droplet size. Droplet size distribution was measured using real-time laser diffraction and the volume median diameter taken as a response. DOE yielded information on the relationship three critical process parameters: pump rate, atomisation pressure and coating-polymer concentration, had upon droplet size. The model generated was robust, scoring highly for model fit (R2 = 0.977), predictability (Q2 = 0.837), validity and reproducibility. Modelling confirmed that all parameters had either a linear or quadratic effect on droplet size and revealed an interaction between pump rate and atomisation pressure. Fluidised bed coating of tablet cores was performed with either small or large droplets followed by CLSM and XμCT imaging. Addition of commonly used contrast materials to the coating solution improved visualisation of the coating by XμCT, showing the coat as a discrete section of the overall tablet. Imaging provided qualitative and quantitative evidence revealing that smaller droplets formed thinner, more uniform and less porous film coats.

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Divisions: College of Health & Life Sciences > Aston Pharmacy School
College of Health & Life Sciences
College of Health & Life Sciences > Chronic and Communicable Conditions
Additional Information: © 2016 Dennison et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: MRC CASE award (Grant No. MR/J01236X/1) with Viridian Pharma Ltd. Data Availability Statement: All relevant data are within the paper.
Uncontrolled Keywords: Agricultural and Biological Sciences(all),Biochemistry, Genetics and Molecular Biology(all),Medicine(all)
Publication ISSN: 1932-6203
Last Modified: 17 Jun 2024 07:21
Date Deposited: 26 Sep 2016 12:30
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2016-08-22
Accepted Date: 2016-04-28
Submitted Date: 2015-11-11
Authors: Dennison, Thomas J.
Smith, Julian
Hofmann, Michael P.
Bland, Charlotte E.
Badhan, Raj K. (ORCID Profile 0000-0002-0904-9324)
Al-Khattawi, Ali (ORCID Profile 0000-0002-2498-2817)
Mohammed, Afzal R. (ORCID Profile 0000-0002-5212-3040)



Version: Published Version

License: Creative Commons Attribution

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