Manganese-based contrast agents (MnCAs) have emerged as suitable alternatives to gadolinium-based contrast agents (GdCAs). However, due to their kinetic lability and laborious synthetic procedures, only a few MnCAs have found clinical MRI application. In this work, we have employed a highly innovative single-pot template synthetic strategy to develop a MnCA, MnLMe, and studied the most important physicochemical properties in vitro. MnLMe displays optimized r 1 relaxivities at both medium (20 and 64 MHz) and high magnetic fields (300 and 400 MHz) and an enhanced r 1 b=21.1 mM-1 s-1 (20 MHz, 298 K, pH 7.4) upon binding to BSA (K a=4.2×103 M-1). In vivo studies show that MnLMe is cleared intact into the bladder through renal excretion and has a prolonged blood half-life compared to the commercial GdCA Magnevist. MnLMe shows great promise as a novel MRI contrast agent.
We present a single‐pot template synthesis strategy for a manganese‐based MRI contrast agent, MnLMe. MnLMe is highly inert toward zinc‐transmetallation and displays enhanced T 1 relaxivity upon non‐covalent interaction with serum albumin. In vivo studies show higher contrast enhancement in the liver and longer blood half‐life than that of the commercially available contrast agent Magnevist. MnLMe shows great potential for use as a blood pool agent.
Keywords: Mn-based contrast agents; bishydrated MnCA; blood pool agents; in vivo MRI; template synthesis.
© 2021 The Authors. Angewandte Chemie published by Wiley-VCH GmbH.