(505e) Comparing a Semi-Continuous Tablet Coating Process at Different Scales Using CFD-DEM

Tablet coating is a widely used unit operation in the pharmaceutical industry. Traditionally, large-scale drum coater systems are loaded with hundreds of kilos of tablets and rotate at relatively low rotation rates (Fr<<1). This leads to several hours of batch processing in order to obtain sufficient coating uniformity. The ConsiGma^TM coater from GEA is a tablet coater which can be integrated into the GEA ConsiGma^TM continuous process line. The ConsiGma^TM coater operates with low drum loads (5-7 kg) but very high rotation rates (Fr~1) leading to much shorter cycle times in the range of a few minutes. To achieve better coating results the tablets are jetted away from the rotating drum wall by so-called air knives in order to form a stable, gravity-free cascade. This air flow needs to be considered in a simulation model to accurately predict the coating process in the ConsiGma^TM coater. Depending on the desired throughput rates there are three different types of the GEA ConsiGma^TM coaters, differing in the depth of the coating drum from 80 to 320 mm.

We developed a computational CFD-DEM model that allows the simulation of the coating process inside the GEA Consigma^TM coaters including tablet fluid interaction. We will show a model to simulate accurately biconvex tablets including a drag model that takes into account the non-sphericity of the tablets. At the end we will compare two different drum scales of the GEA Consigma^TM coater (160 mm width and 320 mm width) and compare the scalability of the drum design. The comparison will include the mixing inside the Consigma^TM coater, as well as the coating performance and the heat transfer during the coating process. Guidance on how to scale between the two tablet coaters will be developed with the help of the simulation results.