Continuous Embedded Droplet Printing in Yield‐Stress Fluids for Pharmaceutical Drug Particle Synthesis

Abstract Embedded droplet printing is a recent mode of generating and processing droplets within yield‐stress fluids. This technique has shown promise for performing sensitive processes like pharmaceutical crystallization, as well as chemical synthesis and biological experimentation due to the unique ability to process droplets that are quiescently suspended. Despite improving on conventional microfluidic technologies in numerous ways, current embedded droplet printing methods are limited to batch processes, severely hampering their overall utility. A new platform that enables continuous production of embedded droplets is presented and characterized. This platform expands the capabilities of embedded droplet printing and allows for its application to areas of continuous materials discovery, screening, and manufacturing. Here, the platform is used for the rapid production of pharmaceutical particles that are highly spherical and uniform, key targets for flowability, and ultimately manufacturability of pharmaceutical drug products. The presented platform achieves a maximum throughput of over 100 g per day, enabling characterization of the superior powder flow properties. The available operating space of this platform is demonstrated for an antisolvent crystallization process with an anti‐malarial drug. This understanding provides design guidelines for how similar platforms may be engineered for precise, rapid, customized, and distributed manufacturing of drug particles with superior flowability.