title: Recent advances in the characterization of amorphous pharmaceuticals by X-ray diffractometry.
abstract: For poorly water soluble drugs, the amorphous state provides an avenue to enhance oral bioavailability. The preparation method, in addition to sample history, can dictate the nature and the stability of the amorphous phase. Conventionally, X-ray powder diffractometry is of limited utility for characterization, but structural insights into amorphous and nanocrystalline materials have been enabled by coupling X-ray total scattering with the pair distribution function. This has shown great promise for fingerprinting, quantification, and even modeling of amorphous pharmaceutical systems. A consequence of the physical instability of amorphous phases is their crystallization propensity, and recent instrumental advances have substantially enhanced our ability to detect and quantify crystallization in a variety of complex matrices. The International Centre for Diffraction Data has a collection of the X-ray diffraction patterns of amorphous drugs and excipients and, based on the available supporting information, provides a quality mark of the data.
authors.affiliation: Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, United States; Characterization Facility, University of Minnesota, Minneapolis, MN 55455, United States.
authors.forename: Seema
authors.initials: S
authors.lastname: Thakral
authors.affiliation: Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, United States.
authors.forename: Maxwell W
authors.initials: MW
authors.lastname: Terban
authors.affiliation: Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, United States; Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, United States.
authors.forename: Naveen K
authors.initials: NK
authors.lastname: Thakral
authors.affiliation: Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, United States. Electronic address: surya001@umn.edu.
authors.forename: Raj
authors.initials: R
authors.lastname: Suryanarayanan
mesh_terms: D001682:Biological Availability; D003460:Crystallization; D005079:Excipients; D004364:Pharmaceutical Preparations; D012995:Solubility; D014961:X-Ray Diffraction
chemical_list: D005079:Excipients; D004364:Pharmaceutical Preparations
keywords: Amorphous; Crystallization; Solid dispersion; Total scattering pair distribution function; X-ray diffractometry