AstraZeneca’s $25B of annual sales depends on a wide range of products, 80% of which are isolated and formulated in their crystalline state. The appearance of extreme crystal morphologies (EMs) - long needles (aspect ratios up to 100) and thin plates - leads to significant reproducibility and scale up problems during processing, product development and commercial manufacture. Solvent/impurity inclusion, long filtration times, adhesion to processing equipment, low bulk density, poor flow or difficulties with milling are typical issues, resulting in time lost, additional resource requirements and reduced supply chain flexibility. At UoM under EP/I013563/1 we discovered that such extreme morphologies are associated with two important physical processes: rapid molecular integration into growing crystal faces and mass transfer controlled growth. In extreme cases this is manifest by crystals growing as hollow needles. In this proposal we intend to utilise this discovery to develop workflows which mitigate AZ’s problems with EMs.