(119c) Continuous Solid-Liquid Separation in Pharmaceutical Manufacturing

Continuous manufacturing
processes offer many advantages for pharmaceutical production. Yet, continuous production is only slowly being
adopted in the industry, main issue being a lack of ready-to-use continuous manufacturing
equipment and missing process knowledge. In contrast to classical chemical
production, small scale equipment would often be required for production of
modern low-volume-high-value patient centred medication. In upstream production
large efforts are already undertaken to close the existing technology gap [1]?[3]. Also, in secondary manufacturing
many groups have formed, working on topics such as continuous wet granulation,
-blending, -direct compaction or -thermal drying.[4], [5] However, at the interface between
primary and secondary manufacturing, solid-liquid removal is a crucial step
during pharmaceutical production.[6], [7] Nevertheless, little work has been
reported regarding the development of continuous equipment for solid-liquid
separation of pharmaceutical products, particularly to allow treatment of small
process streams.

Commercially available
continuous equipment for filtration and thermal drying was selected and
thoroughly analyzed. Representative model APIs were chosen to evaluate the
equipments aptitude to handle small process streams in a continuous
pharmaceutical manufacturing environment.

The equipment's suitability for
pharmaceutical production could be proven. Operation strategies for further
enhancement of filtration performance were developed and successfully
implemented. The achieved increase of permeate rates significantly sustains
economic efficiency of the developed cross-flow filtration setup.  To allow
solvent removal below regulatory limits a spin-flash dryer was used, enabling
treatment of highly viscous slurries under extremely robust process conditions
within a given design space.

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