Application of Continuous‐Flow Processing in Multistep API and Drug Syntheses

The use of flexible and cost-effective manufacturing technologies for the production of active pharmaceutical intermediates (APIs) is one major pathway toward solving drug shortage and inaccessibility, which is a multifaceted global issue. With the introduction of enabling technologies such as continuous-flow processing to the pharmaceutical industry, some of the bottlenecks attributed to API manufacturing that are contributing toward drug shortage and access can easily be mitigated. To demonstrate, most recent routes toward the continuous-flow synthesis of 20 APIs, of which more than 50% are on the World Health Organization's 2018 list of essential medicines, are discussed herein. This chapter aims at highlighting the potential of continuous-flow processing as a viable technology for the efficient and sustainable manufacture of APIs to counteract drug shortage and inaccessibility in order to promote the engagement of relevant stakeholders to facilitate capacity building for local production of essential medicines in affected populations mostly situated in developing economies.