Solid‐state Characterization Techniques

This chapter discusses common analytical techniques used to characterize pharmaceutical solids and identify the crystalline form. The ability of pharmaceutical materials to crystallize as different solid-state forms has required a variety of techniques to identify the solid form as well as its properties. Identification of crystalline forms has been limited in visual microscopic methods, unless the forms have been fully characterized. The chapter provides summary of LY334370 hydrochloride (HCl) crystalline forms. X-ray powder diffraction (XRPD) can provide information on crystallinity, thermal methods will assess thermal transitions, spectroscopy can distinguish environments and bonding patterns, and water sorption will establish hygroscopicity/hydrate formation. Once the characterization information has been obtained, other data can be combined with this information for selecting the best form for development. Relationships between the forms can be used to help understand and prevent process-induced transformations during active pharmaceutical ingredient (API) and drug product processes, such as drying, milling, and granulation.