Co-Crystallization. A Perspective on Current Practices

Within the pharma industry active ingredients are commonly formulated as solid dosages, however the properties of the solid form of the actives are not always ideal. Therefore, crystal engineering is often employed to improve properties. Co-crystals are a form of crystal engineering that is gaining an increased level of interest within pharma.

Co-crystals have been shown to improve physiochemical properties such as solubility, stability, taste masking, dissolution profile, bioavailability, and melting point. There are many reported techniques that can be used to screen for co-crystals including:

  • Solvent drop grinding
  • Evaporation
  • Cooling
  • Anti-solvent
  • Slurrying

The Crystal16 is a powerful system used for diverse solid state screening including co-crystal formation. Using 16 parallel reactors, you can test a wide diversity of crystallization conditions such as solvents and solvent mixtures, compound concentrations, coformers, temperature profiles. However, conventional screening methods use stoichiometric quantities of the components and may miss a significant number of potential co-crystals. Using a systematic approach to co-crystal screening using the clear point information generated with the Crystal16, it is possible to improve the probability of finding potential co-crystals as well as construct phase diagrams to better understand the co-crystal landscape.

The workshop presented by Dr. Thomas Kendall shows how the Crystal16 instrument enables a systematic approach to co-crystal screening.



1. Thomas Kendall, Sam Stratford, Adam R. Patterson, Ruth A. Lunt, Dyanne Cruickshank, Thierry Bonnaud, C. Daniel Scott; Progress in Medicinal Chemistry, Volume 60, 2021, 345-442

2. J. H. ter Horst, M. A. Deij, P. W. Cains; Crystal Growth & Design, Vol. 9, No. 3, 2009