title: A new tetrahydrated form of sodium naproxen.
abstract: The anhydrous sodium naproxen (ASN) can form several hydrated phases if maintained at different relative humidities (RH). The water uptake can promote crystallographic modifications, according to the amount of water. In a previous work, the authors showed that a dihydrated form could be obtained either by crystallization in water or by exposure of the anhydrous form to a RH of 55%. In the present work, the authors report about the formation and characterization of a new tetrahydrated form, obtained by exposing the ASN to RH >or= 75%. All the hydrated compounds were characterized by the combined use of several spectroscopic, thermal, and crystallographic techniques. The thermal stability of both the dihydrated and tetrahydrated compounds was also tested.
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Camerino, Via S. Agostino, Camerino, Italy. piera.dimartino@unicam.it
authors.forename: Piera
authors.initials: P
authors.lastname: Di Martino
authors.forename: Christine
authors.initials: C
authors.lastname: Barthélémy
authors.forename: Etienne
authors.initials: E
authors.lastname: Joiris
authors.forename: Doretta
authors.initials: D
authors.lastname: Capsoni
authors.forename: Admir
authors.initials: A
authors.lastname: Masic
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Massarotti
authors.forename: Roberto
authors.initials: R
authors.lastname: Gobetto
authors.forename: Marcella
authors.initials: M
authors.lastname: Bini
authors.forename: Sante
authors.initials: S
authors.lastname: Martelli
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002626:Chemistry, Pharmaceutical; D018360:Crystallography, X-Ray; D003890:Desiccation; D004355:Drug Stability; D006813:Humidity; D009682:Magnetic Resonance Spectroscopy; D009288:Naproxen / Q000737:chemistry*; D011208:Powders; D012964:Sodium / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013816:Thermodynamics; D013818:Thermogravimetry; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D011208:Powders; D014867:Water; D009288:Naproxen; D012964:Sodium