title: Solid-state properties of creatine monohydrate.
abstract: Creatine monohydrate (CM) is a nutritional supplement and an ergogenic aid for athletes. It appears to increase lean body mass, high-intensity power output and strength in healthy humans. The crystal structure of creatine monohydrate has previously been reported. However, little information is available on its solid-state properties. In this investigation, creatine monohydrate was subjected to Thermal Analyses, Karl-Fisccher Titrimetry (KFT), Scanning Electron Microscopy (SEM), and Variable Temperature X-ray Powder Diffractometry (VTXRD) to characterize its solid-state properties. The results of this study suggested that commercially available creatine monohydrate dehydrates at about 97-125 degrees C. A phase transition after dehydration was confirmed by X-ray diffraction studies. This dehydrated phase at a temperature above 230 degrees C undergoes intramolecular cyclization with a loss of an additional mole of water to form creatinine. Creatinine finally melts with decomposition at about 290 degrees C. VTXRD, confirmed that the above solid-state thermal transformation was kinetically driven, and occurred within a narrow temperature range. Mass Spectrometric (MS) studies further indicated a possible dimerization of creatinine formed during the solid-state transformation.
authors.affiliation: Department of Pharmacy Sciences, School of Pharmacy and Allied Health Professions, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178, USA. adash@creighton.edu
authors.forename: Alekha K
authors.initials: AK
authors.lastname: Dash
authors.forename: Yoonsun
authors.initials: Y
authors.lastname: Mo
authors.forename: Abira
authors.initials: A
authors.lastname: Pyne
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002851:Chromatography, High Pressure Liquid; D003401:Creatine / Q000737:chemistry*; D004055:Differential Thermal Analysis; D007700:Kinetics; D013058:Mass Spectrometry; D008855:Microscopy, Electron, Scanning; D012995:Solubility; D014961:X-Ray Diffraction
chemical_list: D003401:Creatine