Scaling Intra-Tablet Coating Variability

Pharmaceutical tablets usually exhibit variability in coating thickness, both across individual tablets as well as over a single tablet’s surface. In this work, the coefficient of variation in coating thickness, referred to as intra-tablet coating variability, is examined as a function of processing scale. The discrete element method (DEM) is used to simulate the dynamics of two different tablet shapes in coating pans of four different sizes. The asymptotic intra-tablet coating variability is observed to increase with increasing pan size. Studies designed to explain the observed trend are also presented.