Removal of Gadolinium Ions and Gadolinium Contrast MRI Agents Using Modified Sea Sand Substrate from Water Environment

Abstract

Gadolinium in the form of complex compouds is used as a contrast agent in medicine diagnostic for magnetic resonance imaging. Gadolinium‑based contrast agents are divided into linear and macrocyclic substances (Ionic and Nonionic). Gd3+ toxic ion can be replaced by cations such as Fe3+ and Cu2+. Gadolinium inhibits the activity of some enzymes dependent on calcium. This macrocyclic compound binds Gd3+ more strongly than the linear complexes. In the case of this study, the influence of Fe3+ and Cu2+ ions on the displacement of Gd3+ from the macrocyclic MRI contrast agent Gadovist® (Gadobutrol) was studied. For comparison with Gadovist transmetalation of Gd3+ ions, the removal experiments of Gd3+ ions themselves from the water environment were performed. For this purpose, was used sea sand which was modified by 3‑aminopropyltriethoxysilane. These molecules are capable to capture Gd3+ ions, as was confirmed by ICP-MS measurements. The prepared samples of modified sea sand were also characterized by FTIR and TGA measurements. In the case of Gd3+ ions alone, a significant decrease in Gd3+ ions concentration was observed on the modified sea sand. The experiments carried out for Gadovist proved that in the case no release of Gd3+ ions was observed when testing the influence of two different weight concentrations of Fe3+ and Cu2+, 1% and 10% related to the weight concentration of modified sea sand for displacement Gd3+ from the Gadovist. The ICP-MS showed no release of Gd3+ ions to the water environment.

Keywords: Gadolinium, Magnetic resonance contrast agent, Modified sea sand, Removal of gadolinium.