Scale Up of Pan Coating Process Using Quality by Design Principles

Scale up of pan coating process is of high importance to the pharmaceutical and food industry. The number of process variables and their interdependence in a pan coating process can make it a rather complex scale-up problem. This review discusses breaking down the coating process variables into three main categories: pan-related, spray-related, and thermodynamic-related factors. A review on how to scale up each of these factors is presented via two distinct strategies--"macroscopic" and "microscopic" scale-up. In a Quality by Design paradigm, where an increased process understanding is required, there is increased emphasis on "microscopic" scale-up, which by definition ensures a more reproducible process and thereby robust scale-up. This article also reviews the various existing and new modeling and process analytical technology tools that can provide additional information to facilitate a more fundamental understanding of the coating process.