Signal Amplification by Reversible Exchange for COVID-19 Antiviral Drug Candidates

Several drug candidates have been proposed and tested as the latest clinical treatment for the coronavirus pneumonia (COVID-19). Chloroquine, hydroxychloroquine, ritonavir/lopinavir, and favipiravir are proved to be effective after treatment. The hyperpolarization technique presents an ability to further understand the roles of these drugs at the molecular scale and applications in nuclear magnetic resonance/magnetic resonance imaging (NMR/MRI). This technique may provide new opportunities in diagnosis and biomedical research to cope with COVID-19. Signal amplification by reversible exchange (SABRE)-based hyperpolarization studies on large-sized drug candidates were carried out. We observed hyperpolarized proton signals from whole structures, due to the unprecedented long-distance polarization transfer by para-hydrogen. We also found that the optimum magnetic field for the maximum polarization transfer yield was dependent on the molecular structure. Therefore, future research on isotope labelling and polarization transfer on long T1 time nuclei including clinical perspectives can help us overcome this worldwide pandemic.