Ga-68 Labeled Hexa-Lactoside PET Imaging Agent
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Solution Overview
Problem
The limited availability and stability issues of indium-111 polylactoside imaging agents hinder their widespread use for accurately quantifying reserved hepatocytes in liver diseases, such as liver cirrhosis and cancer, due to production constraints and instability.
Innovation Solution
A method for radiolabeling a hexa-lactoside positron emission tomography (PET) imaging agent with Ga-68 using a specific chelating agent, p-NCS-benzyl-triazanonane diacetic acid-glutamic acid (p-NCS-benzyl-NODA GA), which forms six coordination bonds with Ga-68, ensuring high stability and labeling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If indium-111 polylactoside imaging agents are used for liver receptor imaging, then imaging capability is provided, but availability is limited and stability is poor
Solution Approach 1:
The patent changes the radionuclide parameter from indium-111 to gallium-68, which has better availability through generator production and improved stability characteristics. This parameter substitution resolves the contradiction by maintaining imaging functionality while achieving both higher reliability and availability.
Solution Approach 2:
The patent creates a gallium-68 labeled hexa-lactoside agent that copies the successful imaging mechanism of indium-111 polylactoside while improving upon its limitations. The hexa-lactoside chelating structure is optimized to work with gallium-68, providing a replicated but superior imaging agent.
2Quantity of substance
If Ga-68 is used as radionuclide for PET imaging, then availability and imaging quality improve, but labeling stability was initially poor compared to Tc-99m agents
Solution Approach 1:
The patent develops a composite chelating system using hexa-lactoside coupled with NODA-GA, which specifically coordinates with gallium-68. This composite material design provides six coordination bonds between the chelator and Ga-68, ensuring high labeling stability (>98% radiochemical purity maintained for up to 4 hours) while preserving the availability benefits of Ga-68.
3Measurement precision
If hexa-lactoside is used as chelating agent, then binding affinity to asialoglycoprotein receptor is enhanced, but labeling efficiency and stability with Ga-68 requires optimization
Solution Approach 1:
The patent performs preliminary coupling of hexa-lactoside to the NODA-GA chelating framework before Ga-68 labeling. This pre-organization of the chelating structure ensures optimal geometry for Ga-68 coordination, achieving both high binding affinity to the asialoglycoprotein receptor and high labeling efficiency in a single-step labeling process.
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 Ga-68-labeled hexa-lactoside PET imaging agent achieves a labeling efficiency of over 98% and maintains radiochemical purity greater than 98% for up to 4 hours, providing clear and stable PET images suitable for liver receptor imaging.
Implementation Method 1
which forms six coordination bonds with Ga-68, ensuring high stability and labeling efficiency
Data Source
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AI summary
The present invention provides a hexa-lactoside-triazanonane triacetic acid (NOTA) derivative, a method for radiolabeling a hexa-lactoside positron emission tomography (PET) imaging agent for a liver receptor with Ga-68, and a hexa-lactoside PET imaging agent for a liver receptor. The hexa-lactoside-NOTA derivative is a conjugate of six chains of lactose with NOTA obtained by conjugating hexa-lactoside to a chelating agent p-thiocyanate-benzyl-triazanonane diacetic acid-glutamic acid in the presence of triethyl amine/dimethyl formamide as a solvent. The radiolabeling method comprises labeling with Ga-68 at room temperature. According to the present invention, the labeling effect is stable, the labeling efficiency of the labeled product is greater than 95%, the labeled product is highly stable and the radiochemical purity is still greater than 90% after 4 hours.