Perfluorinated Iridium Catalyst for Signal Amplification by Reversible Exchange Provides Metal-Free Aqueous Hyperpolarized [13C1]-Pyruvate

Motivation: Signal Amplification by Reversible Exchange (SABRE) recent progresses include hyperpolarizing [1-13C]pyruvate in aqueous solutions. However, overcoming the challenge of iridium toxicity in hyperpolarized mixtures is essential for broader biocompatible SABRE applications. Goal(s): The removal of Ir metal from hyperpolarized SABRE mixtures is an unmet need with substantial clinical significance. Approach: A perfluorinated SABRE catalyst was developed to counter iridium contamination in hyperpolarized aqueous solutions by exploiting its high hydrophobicity for straightforward separation. Results: The residual Ir was found to be only 177 ppb, representing a 8130-fold reduction in Ir concentration and the lowest and safest level reported to date for a SABRE-hyperpolarized solution. Impact: Hyperpolarizing [1-13C]pyruvate using a perfluorinated SABRE catalyst reduced the residual iridium levels to safe levels for human injection. Future development along with solvent removal could make SABRE-SHEATH a faster and cost-effective alternative for biocompatible hyperpolarized agents in next-generation molecular imaging.