Galactose-Targeted Peptide Radiopharmaceuticals for PET Liver Imaging
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Solution Overview
Problem
The translation of human serum albumin-based radiotracers for liver function imaging into clinical practice is limited due to regulatory requirements for GMP-compliant labeling precursors, necessitating the development of low molecular weight, synthetic galactose carriers for non-invasive determination of asialoglycoprotein receptor expression and functional hepatic reserve.
Innovation Solution
Development of peptide-based low molecular weight radiopharmaceuticals, specifically compounds of formula (I), which include chelating groups like NODAGA and NOTA, linked to galactose residues for targeting hepatocytes, enabling imaging and quantification of hepatic function using PET imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If human serum albumin-based radiotracers are used for liver function imaging, then imaging capability is achieved, but regulatory compliance and GMP-compliant labeling become problematic
Solution Approach 1:
The patent replaces human serum albumin (a complex biological macromolecule) with small synthetic peptide compounds containing galactose residues. These synthetic peptides are easier to manufacture under GMP conditions, have defined structures, and can be produced as disposable radiotracers without the regulatory complexities of biological products.
Solution Approach 2:
The invention changes the molecular parameters from large protein-based radiotracers (human serum albumin, ~66 kDa) to small peptide-based radiotracers (low molecular weight). This parameter change enables better control over synthesis, purification, and regulatory compliance while maintaining the essential function of targeting asialoglycoprotein receptors on hepatocytes.
2Ease of manufacture
If low molecular weight synthetic galactose carriers are developed, then regulatory compliance improves, but metabolic stability may be reduced
Solution Approach 1:
The patent creates composite peptide structures combining galactose residues with peptide backbones and chelating groups. These composite molecules integrate multiple functional elements: the galactose provides target specificity for ASGR, the peptide structure provides metabolic stability through controlled composition, and the chelating group enables radiolabeling. This composite approach resolves the contradiction between small size/regulatory compliance and metabolic stability.
Solution Approach 2:
The invention extracts only the essential functional element (galactose residue for ASGR targeting) from the complex human serum albumin structure and combines it with a simplified peptide backbone. This extraction eliminates unnecessary complexity that caused regulatory issues while maintaining the core metabolic stability function through careful peptide design.
3Ease of manufacture
If peptide-based radiopharmaceuticals are used, then manufacturing ease improves, but binding affinity to ASGR may be reduced compared to multivalent ligands
Solution Approach 1:
The patent designs peptide compounds that perform multiple functions: they provide ASGR targeting through galactose residues, maintain metabolic stability through peptide structure, enable radiolabeling through chelating groups, and achieve sufficient binding affinity through optimized galactose-peptide conjugation. This multi-functionality allows single-component peptides to achieve what previously required complex multivalent systems.
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 peptide-based radiopharmaceuticals provide high metabolic stability and allow for accurate, non-invasive determination of hepatic function, overcoming regulatory barriers and enhancing imaging resolution and quantification capabilities.
Implementation Method 1
compounds of formula (I), wherein D is a chelating group or a prosthetic group or a [18F]-label
Implementation Method 2
enabling imaging and quantification of hepatic function using PET imaging
Implementation Method 3
Peptide-based radiopharmaceuticals for non-invasive imaging of the functional liver reserve
Data Source
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AI summary
The present invention relates to peptide-based radiopharmaceuticals of formula (I) for non-invasive imaging of the functional liver reserve.