High-Contrast and Fast-Removable ¹⁹ F-MRI Labels with Perfluoro-tert-Butyl Substituents

¹⁹ F MRI is a unique technique for tracking and quantifying the indicator (¹⁹ F-MRI label) in vivo without the use of ionizing radiation. Here we report new ¹⁹ F-MRI labels, which are compounds with perfluoro-tert-butyl groups: 1,2-bis(perfluoro-tert-butoxy)ethane (C₁₀ F₁₈ H₄ O₂ ) and 1,3-bis(perfluoro-tert-butyl)propane (C₁₁ F₁₈ H₆ ). Both substances contain 18 equivalent ¹⁹ F atoms, constituting 68.67 % and 71.25 % of the molecule, respectively. The emulsions with ¹⁹ F molecules were prepared and used in ¹⁹ F MRI studies in laboratory rats in vivo. The substances demonstrated high contrast properties, good biological inertness and the ability to be rapidly eliminated from the body. We showed that at a dose of 0.34 mg/g of body weight in rats, the time for complete elimination of C₁₀ F₁₈ H₄ O₂ and C₁₁ F₁₈ H₆ is ∼30 days. The results turned out to be promising for the use of the presented compounds in ¹⁹ F MRI applications, especially since they are quite easy to synthesize.