The role of asymmetric flow field-flow fractionation in drug development - From size separation to advanced characterization

Drug development is a complex multi-stage process that aims to deliver therapeutic products to the market. This process employs different analytical methods to separate and characterise compounds, monitor manufacturing, and validate the final drug products to ensure their safety, quality, and efficacy. However, advancements in modern drug development and discovery have led to new types of the therapeutical products of increasing complexity. As such, the capabilities of some traditional analytical techniques have become limited, and the demand for using advanced analytical techniques like field-flow fractionation (FFF) has been increasing. A special feature offered by the FFF family is a unique way of separation based on the analytes' specific physicochemical properties. As such, FFF is a powerful tool for analysing diverse analytes and complex mixtures. Herein, asymmetric flow field-flow fractionation (AF4) is the most frequently used technique within the FFF family in drug development. Therefore, this review aims to provide a general overview of the usage of AF4 technology in the drug development field.