Polymorphism of Gadolinium Diethylenetriaminepentaacetic Acid Bis(methylamide) (GdDTPA-BMA) and Dysprosium Diethylenetriaminepentaacetic Acid Bis(methylamide) (DyDTPA-BMA).

Hydrates of Gadolinium Diethylenetriaminepentaacetic Acid Bis(methylamide) as Studied by X-ray Diffraction

“…Crystallisation of gadodiamide from a water/acetone system produced colourless needles, whereas crystallisation of gadodiamide from water produced both colourless needles and colourless blocklike crystals. The needles from the two experiments gave identical IR spectra, which were identical to that reported for gadodiamide I . In addition the observed water contents, 12.1 and 12.7%, respectively (see Experimental Section), are typical for what is found for gadodiamide I (normally 11−14%, corresponding to 4−5 water molecules per gadodiamide complex).…”

“…Gadodiamide (Figure ) is the active ingredient in OMNISCAN (Nycomed Imaging AS, Oslo, Norway), a paramagnetic contrast agent for magnetic resonance imaging (MRI) . During the development of OMNISCAN five different forms of gadodiamide, denoted types I − V , were obtained, most of which proved to be hydrates with variable water content (Table ) . As reported 2 precipitation or crystallisation of gadodiamide from aqueous solutions affords only type I and type III hydrates.…”

“…From Table it is apparent that some of the gadodiamide samples have identical composition and can therefore be regarded as polymorphs or polymorphic forms . To uncover any structural features, which could lead to polymorphism, we wanted to determine the structure of as many types of gadodiamide as possible by X-ray crystallography.…”

Lanthanide complexes on Ag nanoparticles: Designing contrast agents for magnetic resonance imaging

“…9a). The mass loss in this region is generally attributed to the dissociation of bound water such as described in a study by Aukrust et al on the lanthanide complex GdDTPA bis(methylamide) [49]. Following the dissociation of water, these workers observed the onset of decomposition of the complex in the 300-320°C region.…”

“…For the compound [Gd(DTPA-L-cys)]{Ag} (6), mass loss in the region below 300°C likely corresponds to both weakly and strongly bound water [49,51]. The strongly bound water fraction might be covalently bound to Gd 3+ ions.…”