Prediction of tablet velocity in pan coaters for scale-up

The purpose of this study was to investigate the influence of scale-up on the tablet velocity and surface time of tablets (oblong and biconvex) in the spray zone of different perforated pan coaters. A Bohle Film Coater (BFC) 5 and 10 for the laboratory scale, a BFC 40 for the pilot scale and a BFC 200 for the production scale were used. The pan speeds were scaled-up using the same peripheral speeds. The tablet velocities for 5 peripheral speeds were determined using video imaging of blue tracer tablets. An increasing pan size resulted in a higher tablet velocity and lower surface time in the spray zone for same peripheral speeds. A mathematical model in the literature was proved to predict the tablet velocities in scale-up in the BFCs. The tablet velocities in the pilot or production scale can be predicted based on the measured tablet velocities in the laboratory scale. Furthermore, depending on the pan size, the increase in tablet velocity (RV-value) can be predicted for the scale-up process using BFCs. The RV-values were validated for three pan sizes, different pan speeds and three different tablet types. The RV-value can be used as a correction factor to calculate the scaled-up spray rate based on the same spray rate per spray width ratios.