(657e) Experimental and Numerical Study On the Tablet Velocity In Commercial Scale Pan Coaters

      Effective control of coating uniformity in a tablet coating process requires good mixing.  Scaling up a pan coating process from lab to commercial scale to maintain the same level of tablet uniformity poses unique challenge.   It was found in our previous study that ^[1] the tablet flow rate, a value calculated from the tablet velocity number density (tablet size) and spray zone width, can be an indicator of the mixing condition.  We have also quantified the impact of the tablet velocity and number density on the tablet content uniformity.  In this paper, the tablet velocity in commercial pan coaters was investigated experimentally and numerically.  This study was carried out in 50kg, 400kg and 600kg pan coaters.  Different types of tablets including oblong and round tablets with weights from 200mg to 1500mg were used in the study.  A real-time imaging device was developed to measure and analyze the tablet flow behavior within the sprayed area.  The current study shows that the smaller round tablets move faster than larger ones in general.  However, for the oblong shape tablet the larger tablets move faster than the smaller ones.  For all the tested tablet types, the tablet velocities increase with increasing air flow rates. This enhancement by air flow starts to level off at the higher air flow rates.  For a given pan size, there appears a pan loading that has the maximum tablet velocities.  The existence of such maxima implies an optimal pan loading at which the desired coating uniformity can be consistently obtained. In the parallel study through the numerical simulation, a Discrete Element Method (DEM) was applied to simulate the tablet flow behaviors in a pan coater.  The simulation results show a good agreement with the experimentally measured tablet velocities.