Originators discover new drug candidates by screening sub­stance libraries containing only a few milligrams per sub­stance. Many synthetic methods employed in library synthesis are not scalable: during further development, they have to be modified or redesigned to deliver quantities for further testing. At this point, custom development and manufacturing organizations (CDMOs) such as Patheon offer to perform the respective process development and manufacturing tasks. In this environment, flow chemistry provides various opportunities, for instance, to scale up even demanding synthetic steps without the need for a re-design, to control synthesis processes to deliver products with predictable quality at all required scales while the ultimately required production scale is still uncertain, to speed up process development through quick screening of reaction parameters, and to intensify processes, which reduces investment and variable, e.g. solvent and raw material costs.
Production of many APIs has moved to the East, freeing up conventional cGMP-rated manufacturing capacity in the West. This hampers decisions to invest in new technology developments that tend to reduce the utilization of this manufacturing capacity further.
In response to the growing number of newly developed APIs with a reduced volume per API the industry will shift towards concepts of manufacturing and quality assurance based on flow processes in flexible modular plants that are quickly reconfigured to supply the variety of small-volume products in the required quality and on short notice.
Further successful implementation of flow chemistry processes in cGMP manufacturing environments will increase confidence in this technology. It will convince manufacturers of APIs to consider developing flow processes or to team up with CDMOs with proven experience in this field.