Modeling and Control of a Continuous Vibrated Fluidized Bed Dryer in Pharmaceutical Tablets Production
Continuous manufacturing of pharmaceuticals shows a great potential in reducing production time, cost, and waste and in increasing the flexibility of tablet production. The QbCon®1 unit developed by L. B. Bohle Maschinen + Verfahren GmbH is one of the field innovations [1]. The unit combines the 3 necessary processes of continuous raw material dosing (premix of excipients and active ingredients), twin-screw wet granulation, and fluid bed drying for the continuous wet granulation and drying of the tableting mixture. A grey box continuum-based model for the drying process is proposed with the aim to be used for a model-based quality control approach. A concept for the control of one of the process main critical quality attributes (CQA), i.e., tableting mixture moisture content, is presented with the aid of a nonlinear model predictive controller (NMPC). The model constructed for the drying process shows a good match to the real process with a maximum of 1.18 % prediction standard deviation from the experimentally measured mean moisture content. Moreover, the model-based controller feasibility is shown using a closed-loop simulation of the NMPC.