title: An insight into water of crystallization during processing using vibrational spectroscopy.
abstract: Many organic molecules used as drugs can incorporate water into their crystal lattice. These compounds are also prone to processing-induced transformations (PITs) because processing often exposes the compounds to moisture, heat and mechanical stress. The aim of this review is to provide an overview of the possibilities for following and understanding hydrate/anhydrate transformations using vibrational spectroscopy (mid-infrared, near-infrared, Raman and terahertz). The review begins with a general section on hydrates, followed by considerations on the impact of these on drug products and a description of transformation mechanisms of hydrates. Moreover, a general introduction is given for the spectroscopic techniques together with a discussion of critical issues for quantification models. Unit operations that may induce transformations in hydrate systems are discussed with focus on the published work on the use of spectroscopy to derive information from these processes. Finally, the effect of excipients on PITs is discussed.
authors: Faculty of Pharmaceutical Sciences, Department of Pharmaceutics and Analytical Chemistry, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark.
authors: Anna Cecilia
authors: AC
authors: Jørgensen
authors: Clare J
authors: CJ
authors: Strachan
authors: Kati H
authors: KH
authors: Pöllänen
authors: Vishal
authors: V
authors: Koradia
authors: Fang
authors: F
authors: Tian
authors: Jukka
authors: J
authors: Rantanen
mesh_terms: D003460:Crystallization; D005079:Excipients / Q000737:chemistry; D012995:Solubility; D013055:Spectrophotometry, Infrared / Q000379:methods; D013057:Spectrum Analysis / Q000379:methods*; D013059:Spectrum Analysis, Raman / Q000379:methods; D014732:Vibration; D014867:Water / Q000737:chemistry*
chemical_list: D005079:Excipients; D014867:Water