Water transport and absorption in pharmaceutical tablets – a numerical study
Artikel i vetenskaplig tidskrift, 2020

The quality of a coated pharmaceutical tablet can be strongly affected by the interactions of water droplets with the porous substrate during processes such as coating process. Three different mechanisms co-exist in the coating process: water spreading, absorption and evaporation. Disentangling the fundamental understanding of these phenomena can therefore be crucial for achieving a higher quality of the products (e.g. a longer shelf-life of the tablets) and for controlling the efficiency of the process. This paper aims to investigate the spreading and absorption mechanisms after droplet impingement on a tablet using a Lattice-Boltzmann methodology. Our numerical results (droplet height and spreading, penetration depth and absorbed volume) are in a good agreement with experimental data and numerical simulations available in the literature. In particular, the spreading phase is characterised by the capillary spreading time scale, as confirmed by previous studies. In contrast to previous studies, we find that the absorption process begins at times shorter than the capillary spreading time but with a different power-law in the absorbed volume. We explain this behaviour through a modified Washburn law that takes into account three-dimensional effects. Our data can be used as a benchmark to test novel mathematical models.

Droplet impact

Porous tablets

Mathematical modelling


Pharmaceutical coating


Povilas Vaitukaitis

Chalmers, Mekanik och maritima vetenskaper, Strömningslära

Dario Maggiolo

Chalmers, Mekanik och maritima vetenskaper, Strömningslära

Johan Remmelgas

AstraZeneca R&D

Susanna Abrahmsén-Alami

AstraZeneca R&D

Diana Bernin

Chalmers, Kemi och kemiteknik, Kemiteknik, Kemisk apparatteknik

Maria Daniela Irene Siiskonen

Chalmers, Industri- och materialvetenskap, Produktutveckling

Johan Malmqvist

Chalmers, Industri- och materialvetenskap, Produktutveckling

Srdjan Sasic

Chalmers, Mekanik och maritima vetenskaper, Strömningslära

Gaetano Sardina

Chalmers, Mekanik och maritima vetenskaper, Strömningslära


0025-6455 (ISSN) 1572-9648 (eISSN)

Vol. 55 2 421-433


Farmaceutisk synteskemi

Kemiska processer

Strömningsmekanik och akustik


Hållbar utveckling




C3SE (Chalmers Centre for Computational Science and Engineering)



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