Iali W, Moustafa GAI, Dagys L, Roy SS.
15 N hyperpolarisation of the antiprotozoal drug ornidazole by Signal Amplification By Reversible Exchange in aqueous medium.
MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021;
59:1199-1207. [PMID:
33656772 DOI:
10.1002/mrc.5144]
[Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 02/19/2021] [Accepted: 02/24/2021] [Indexed: 06/12/2023]
Abstract
Signal amplification by reversible exchange (SABRE) offers a cost-effective route to boost nuclear magnetic resonance (NMR) signal by several orders of magnitude by employing readily available para-hydrogen as a source of hyperpolarisation. Although 1 H spins have been the natural choice of SABRE hyperpolarisation since its inception due to its simplicity and accessibility, limited spin lifetimes of 1 H makes it harder to employ them in a range of time-dependent NMR experiments. Heteronuclear spins, for example, 13 C and 15 N, in general have much longer T1 lifetimes and thereby are found to be more suitable for hyperpolarised biological applications as demonstrated previously by para-hydrogen induced polarisation (PHIP) and dynamic nuclear polarisation (DNP). In this study we demonstrate a simple procedure to enhance 15 N signal of an antibiotic drug ornidazole by up to 71,000-folds with net 15 N polarisation reaching ~23%. Further, the effect of co-ligand strategy is studied in conjunction with the optimum field transfer protocols and consequently achieving 15 N hyperpolarised spin lifetime of >3 min at low field. Finally, we present a convenient route to harness the hyperpolarised solution in aqueous medium free from catalyst contamination leading to a strong 15 N signal detection for an extended duration of time.
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