Fluidized pellet coating processes are commonly used when developing a novel solid formulation. Yet there are often process inefficiencies and inconsistencies during scale-up. A successful fluid bed coating process establishes a repeatable endpoint particle distribution to achieve repeatable content uniformity and dissolution profiles. However, inconsistencies occur during scale-up with varying raw materials or changing process dynamics such as segregation, agglomeration, or attrition. The application of in-situ particle monitoring techniques, Lasentec FBRM and PVM is demonstrated to track a series of spray coating batches while varying the batch volume, column diameter, spray rate, humidity, temperature, atomization pressure and excipients. FBRM and PVM allow a user to link process control parameters to the particle size distribution and product quality. Target particle distributions were obtained by controlling critical control parameters during scale up.