Visualization of fluid-bed granulation with self-organizing maps

The degree of the instrumentation of pharmaceutical unit operations has increased. This instrumentation provides information of the state of the process and can be used for both process control and research. However, on-line process data is usually multidimensional, and is difficult to study with traditional trends and scatter plots. The Self-Organizing Map (SOM) is a recognized tool for dimension reduction and process state monitoring. The basics of the SOM and the application to on-line data collected from a fluid-bed granulation process are presented. As a batch process, granulation traversed through a number of process states, which was visualized with SOM as a two-dimensional map. In addition, it is demonstrated how the differences between granulation batches can be studied. The results suggest that SOM together with new in-line process analytical solutions support the in-process control of the pharmaceutical unit operations. Further, a novel research tool for understanding the phenomena during processing is achieved.