Dimeric MRI Contrast Agents Enhancing Relaxivity
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Solution Overview
Problem
Current MRI contrast agents, particularly those with Gd(III) chelates, face challenges in achieving high relaxivity, which limits their diagnostic efficacy and requires higher doses and longer imaging times, while also posing toxicity risks due to free metal ion release.
Innovation Solution
Development of novel dimeric macrocyclic chelating ligands with hydroxylated residues linked through an aminic moiety, forming stable complexes with paramagnetic metal ions like Gd(III), enhancing relaxivity and stability, thereby reducing toxicity and improving imaging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional Gd(III) chelate contrast agents are used, then diagnostic imaging is achieved, but relaxivity is insufficient requiring higher doses and longer imaging times
Solution Approach 1:
The patent merges two macrocyclic chelating units into a single dimeric structure, creating a bifunctional contrast agent that contains multiple Gd(III) binding sites. This merging increases the effective concentration of paramagnetic centers per molecule, thereby enhancing relaxivity and allowing lower doses to achieve the same imaging效果
Solution Approach 2:
The contrast agent employs a composite molecular structure combining two macrocyclic ligand systems with paramagnetic Gd(III) ions. This composite design creates a molecule with enhanced magnetic properties and improved relaxivity compared to monomeric chelates, addressing the insufficient relaxivity of conventional agents
2Measurement precision
If higher doses of contrast agent are administered, then imaging quality improves, but toxicity increases due to free metal ion release
Solution Approach 1:
The patent changes the molecular parameters of the contrast agent by transitioning from monomeric to dimeric structure. This structural parameter change increases the stability constant of the Gd(III) complex, reducing the likelihood of metal ion release and toxicity even at effective dosing levels
Solution Approach 2:
The dimeric structure creates a more stable complex that acts as a single-use contrast agent with improved safety profile. The enhanced stability ensures the Gd(III) remains chelated throughout the imaging procedure, preventing free metal ion release and associated toxicity
3Device complexity
If conventional monomeric chelates are used, then the structure is simple, but relaxivity is limited
Solution Approach 1:
The patent combines two macrocyclic chelating units into a dimeric structure, increasing the number of paramagnetic Gd(III) ions per molecule. This merging directly increases relaxivity by enhancing the magnetic interaction with surrounding water protons, overcoming the relaxivity limitation of monomeric chelates
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The dimeric complexes exhibit significantly higher relaxivity, allowing for lower doses and shorter imaging times, while maintaining stability and safety, thus enhancing diagnostic imaging capabilities.
Implementation Method 1
novel dimeric macrocyclic chelating ligands with hydroxylated residues linked through an aminic moiety, forming stable complexes with paramagnetic metal ions like Gd(III)
Implementation Method 2
Gd(III) is highly paramagnetic with seven unpaired electrons and a long electronic relaxation time, making it an excellent candidate as a relaxation agent
Data Source
AI summary
The present invention relates to new class of dimeric macrocycles capable of chelating paramagnetic metal ions, their chelated complexes with the paramagnetic metal ions and the use thereof as contrast agents, particularly suitable for Magnetic Resonance Imaging (MRI) analysis.