A Survey of Solid Form Landscape: Trends in Occurrence and Distribution of Various Solid Forms and Challenges in Solid Form Selection

This survey provides a comprehensive analysis of solid form screens for 476 new chemical entities (NCEs) conducted at Pharmaron from 2016 to 2023. The findings from this survey reveal notable trends in polymorphism, salt formation, crystallization behavior and molecular weight (MW) distribution of the NCEs evaluated. Most solid form screens were conducted to select the preferred solid form for Investigational New Drug (IND) enabling projects, others were for candidate selection or late-stage development. Comparison to published historical data was made to show changes in occurrence of counterions/co-formers for salts/co-crystals, polymorphs, and the distribution of MWs over time. Increased complexity in the solid-form landscape and selection of the development form are discussed, including challenges in crystallization and selection of lead forms. The distribution of types of crystal forms and the observation of emerging and disappearing polymorphs are presented. These results highlight the evolving challenges and considerations in solid form screening and form selection and offer insights for future pharmaceutical development and crystallization strategies.