An iron-based T sub(1) contrast agent made of iron-phosphate complexes: In vitro and in vivo studies

• Published in: Magma (New York, N.Y.) N.Y.), 2007-02, Vol.20 (1), p.27-37
• Main Authors: Rodriguez, E, Simoes, R V, Roig, A, Molins, E, Nedelko, N, Slawska-Waniewska, A, Aime, S, Arus, C, Cabanas, ME, Sanfeliu, C, Cerdan, S, Garcia-Martin, M L
• Format: Article
• Language: English
• Subjects: Phos
• ISSN: 0968-5243
• DOI: 10.1007/s10334-006-0066-7

A new iron-based T sub(1) contrast agent consisting of a complex of iron ions coordinated to phosphate and amine ligands (Fe sub((phos)) in short) has been characterized by spectroscopic and magnetic measurements. NMR relaxation studies showed r sub(1) values to be dependent on the phosphate salt concentration, K sub(2)HPO sub(4), present in the medium, r sub(1) reaches a maximum value of 2.5 mM super(-1) s super(-1) for measurements carried out at 7 T and 298 K. super(31)P MRS, Moessbauer spectroscopy and magnetic measurements of Fe sub((phos)) solutions suggest paramagnetic Fe super(3+) ions present in the studied iron-phosphate complex. In vitro and in vivo toxicity experiments with C6 cells and CD1 mice, respectively, demonstrated lack of toxicity for Fe sub((phos)) at the highest dose tested in the MRI experiments (12 mM iron for C6 cells and 0.32 mmol iron/kg for mice). Finally, T sub(1) weighted images of brain tumours in mice have shown positive contrast enhancement of Fe sub((phos)) for tumour afflicted regions in the brain.