CEST MRIによるpHセンサーとしてのイミダゾール化合物の開発
A screening of intramolecularly hydrogen-bonded imidazole derivatives and structurally related heterocyclic compounds was conducted to evaluate their N-H chemical exchange saturation transfer (CEST) MRI contrast characteristics. Among the candidates, imidazole-4,5-dicarboxamides (I45DCs) exhibited the most pronounced contrast effect, generating signals at a chemical shift of 7.8 ppm from water with strong pH dependence. Multiple probes built on this molecular scaffold were evaluated, and intravenous administration experiments demonstrated their feasibility for detecting renal pH in living subjects. This work establishes I45DCs as promising pH-responsive CEST MRI contrast agents.
The N-H protons of imidazole-4,5-dicarboxamide undergo pH-dependent chemical exchange with bulk water protons, generating CEST MRI contrast at 7.8 ppm downfield from water.
Intravenous hydrogen-saline infusion is a clinic-only route and is not viable for everyday self-administration. For routine hydrogen intake, inhalation is the most practical route, but inhalation carries explosion risk and concentration matters (empirical LFL of 10%; high-concentration 66% / 100% devices are not recommended).
See also:
https://h2-papers.org/en/papers/27071959