Quality by Design in the Continuous Manufacturing of Oral Films

Quality by Design (QbD) is a conceptual systemic approach to ensure product quality and process efficiency. In the manufacturing of oral film formulations, which are a promising dosage form for special patient groups, QbD ensures consistent drug distribution, optimal film thickness, and overall product quality. This presentation explores the implementation of QbD in the manufacturing of oral films using various advanced process analytical technology tools, such as white-light interferometry and microwave resonance spectroscopy while the experiments followed a central composed design approach. Further, the internal structure of films was examined using optical coherence tomography and critical quality attributes such as drug distribution, dry film thickness, and weight were assessed. It was demonstrated that white light interferometry enables the control of the wet film thickness and the prediction of the dry film thickness. The application of the microwave sensor allows for in-line determination of the residual moisture content in the films.The application of Optical Coherence Tomography (OCT) in offline measurements has demonstrated that high-resolution cross-sectional images can effectively assess film quality, particularly in terms of homogeneity. By visualizing the internal structures, OCT can identify potential defects. For multilayer films, OCT can verify whether layer separation or merging has occurred.