A key enabler for the future success of continuous manufacturing in pharmaceutical and fine chemical production processes is the control of product quality. Since approx. 90% of all small molecular active pharmaceutical ingredients produced involve a crystallization step, a holistic view on its process chain is crucial in order to ensure a defined particle size distribution, high purity, and specific polymorphic form. Different concepts for small-scale continuous crystallization are available, improving the product qualities in comparison to batch. Continuous solid-liquid separations, on the other hand, are rather scarce. Therefore, we designed and characterized an innovative continuous vacuum screw filter (CVSF) for solid-liquid separation, washing, and drying of suspensions in a small scale (up to 10 g of solid per minute). This contribution shows the general working principle of the CVSF as well as a systematic investigation of varying operating parameters on the particle size distribution (PSD), residual moisture, and residence time distribution of the solid phase. As a model system, L-alanine/water is used. The results show that the PSD can be entirely maintained while ensuring a narrow residence time distribution of the solid phase with axial dispersion numbers between 18.7 and 76.2. The residual moisture is for all experiments in a good range of 20-25%. Furthermore, it could be shown that the operability is possible over 8 h. Summarizing, the modular setup of the CVSF offers a maximized flexibility and thus rapid adaptability to changing market demands and product requirements.

• Technical University of Dortmund

• API

1. API
2. Continuous crystallization
3. continuous filtration
4. continuous solid-liquid separation
5. particle size distribution
6. Pharmaceutical Manufacturing
7. Research Article
8. residence time distribution