Crystalline materials may exist in different crystalline forms, or polymorphs, which though chemically identical, have a different molecular arrangement in their crystal structure. Polymorphs often exhibit different physical and electrical properties, and can affect solubility and bioavailability, especially important for drug products (APIs). Polymorphs exist in many crystalline formation process including drug products, polymers, minerals, pigments and other chemical or biomedical reactions.
Raman scattering is very sensitive to crystal form and can be used for the proper characterization of the polymorphs Distinctive spectral differences are often observed, and Raman can be used as a rapid screening tool for polymorph identification. Raman spectrometers are used to identify the crystal conversions by monitoring polymorph transitions in real-time for process applications. In crystallography, Raman technology is used to predict the orientation growing status through the ratio of Raman peak intensities and changes in peak positions.