Solid form screening (SFS) encompasses the search, preparation, and characterization necessary to identify, isolate, and ensure confidence in the stability and downstream manufacturability of a lead form. In many ways, this process serves as the bridge between drug substance and drug product for new chemical entities.

One major component is the identification of polymorphs, which are differently arranged molecules in the crystalline lattice with the same chemical structure. Early screening, selection and isolation of a lead polymorph helps manufacturers avoid additional costs and delays down the road. Also, solid form screening of salts and cocrystals can provide a solubility enhancement strategy to improve bioavailability of poorly soluble drugs. Solid form screening is highly customizable based on the stage of a drug development cycle. In the following case study from one of Lonza’s SFS customers, the workflow required for polymorph characterization, lead form identification, and crystallization process design has been examined.