Abstract
F-19-magnetic resonance imaging (MRI) is a promising technique that may allow us to measure the concentration of exogenous fluorinated imaging probes quantitatively in vivo. Here, we describe the synthesis and characterisation of a novel geminal bisphosphonate (F-19-BP) that contains chemically equivalent fluorine atoms that show a single and narrow F-19 resonance and a bisphosphonate group that may be used for labelling inorganic materials based in calcium phosphates and metal oxides. The potential of F-19-BP to provide contrast was analysed in vitro and in vivo using F-19-MRI. In vitro studies demonstrated the potential of F-19-BP as an MRI contrast agent in the millimolar concentration range with signal-to-noise ratios (SNR) comparable to previously reported fluorinated probes. The preliminary in vivo MRI study reported here allowed us to visualise the biodistribution of F-19-BP, showing uptake in the liver and in the bladder/urinary system areas. However, bone uptake was not observed. In addition,F-19-BP showed undesirable toxicity effects in mice that prevent further studies with this compound at the required concentrations for MRI contrast. This study highlights the importance of developing F-19-MRI probes with the highest signal intensity achievable. (C) 2016 The Authors. Published by Elsevier B.V.