<i>In vivo</i> studies of fullerene-based materials using endohedral metallofullerene radiotracers

Abstract

Biodistribution studies of a water-soluble radioactive metallofullerene compound have been conducted using BALB/c mice. To this end, a sample containing Ho x @C 82 (x = 1, 2) was purified and derivatized to prepare the water-soluble metallofullerol, Ho x @C 82 (OH) y . This metallofullerol was then neutron-activated ( 165 Ho[n,γ] 166 Ho) to prepare the 166 Ho x @C 82 (OH) y analog as a radiotracer, which was monitored, after intravenous administration, for up to 48 hours by using dissection radioanalysis, and its biodistribution was compared with a control compound, Na 2 [ 166 Ho(DTPA)(H 2 O)]. Results showed selective localization of the 166 Ho x @C 82 (OH) y tracer in the liver but with slow clearance, as well as uptake by bone without clearance. In contrast, excretion of the control compound was nearly quantitative after 1 hour. The fate of 166 Ho was also explored by a metabolism study of 166 Ho x @C 82 (OH) y in Fischer rats. Results indicated 20% excretion of intact 166 Ho x @C 82 (OH) y within 5 days. The present findings demonstrate the feasibility of using water-solubilized metallofullerene radiotracers to monitor the fate of fullerene-based materials in animals, and suggest that water-solubilized fullerene materials, in general, may be useful components in drug design.

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Affiliated Institutions

• Oak Ridge National Laboratory US
• Rice University US
• Center for Nanoscale Science and Technology US
• TDA Research (United States) US

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