UCL Discovery

Mathematical Modeling of Spray Impingement and Film Formation on Pharmaceutical Tablets during Coating

Christodoulou, C; Sorensen, E; García-Muñoz, S; Mazzei, L; (2020) Mathematical Modeling of Spray Impingement and Film Formation on Pharmaceutical Tablets during Coating. Chemical Engineering Research and Design , 153 pp. 768-788. 10.1016/j.cherd.2019.11.029.

Abstract

The application of coating films is an important step in the manufacture of pharmaceutical tablets. Understanding the phenomena taking place during coating spray application provides important information that can be used to reduce the number of defective tablets and select the optimal conditions for the coating process. In this work, we investigate spray impact and film spreading on a tablet while this passes through the spray-zone in a rotating coating drum. To simulate spray impingement, we developed an one-dimensional (1D) spreading model that is based on the mechanical energy equation. We assumed the spray to be uniform and we divided it into arrays of droplets that impinge successively on the substrate orthogonally to its surface. In the mechanical energy equation that describes the coating spreading, we accounted for the rate of work done on the surface of the liquid coating film by the impinging droplets that leads to volume change (film spreading and thickness increase). The novel model we propose in this work can calculate the coating spreading rate and thickness. We implemented the mathematical model employing the gPROMS Modelbuilder platform. To study the effect of coating properties and process parameters on the film spreading rate and on the final liquid film thickness, we performed variance-based sensitivity analysis. The model predictions are in good agreement with experimental data found in the literature.

Type: Article Mathematical Modeling of Spray Impingement and Film Formation on Pharmaceutical Tablets during Coating An open access version is available from UCL Discovery 10.1016/j.cherd.2019.11.029 https://doi.org/10.1016/j.cherd.2019.11.029 English This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. UCLUCL > Provost and Vice Provost OfficesUCL > Provost and Vice Provost Offices > UCL BEAMSUCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering ScienceUCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering https://discovery.ucl.ac.uk/id/eprint/10088106