Digital imaging as a process analytical technology tool for fluid-bed pellet coating process.

Pellet coating processes are usually driven by fairly well optimized procedures, while coating suspension sprayed on pellets and adverse effects, such as agglomeration, can not be seen during coating process and are only detected at the very end of the process, when it is too late for any adjustments of the coating process. The aim of this study is to evaluate digital visual imaging as process analytical technology (PAT) tool for fluid-bed pellet coating processes. The method accurately estimates spherical diameter, coating thickness and adverse agglomeration of pellets by contactless measurements, classification and analysis of pellets based on digital imaging. Calibration and thorough assessment of the accuracy, precision, stability and speed of the proposed method was performed with high precision bearing balls. The obtained results on real pellets indicated that the method is feasible for real-time controlling, understanding, designing and optimizing of fluid-bed pellet coating processes according to PAT guidance.