Michael A. BernsteinAstraZeneca R&D Charnwood, Bakewell Road, Loughborough, Leics. LE11 5RH, UK. E-mail: michael.bernstein@astrazeneca.com

Process Analytical Technology (PAT) is a US Food and Drug Administration (FDA) initiative to improve drug substance manufacturing. Control over production processes and impurity production are key elements. These lead to more robust and cheaper production processes, facilitate predictable scale-up and technology transfer and more effectively manage the risk.