F-18 Labeling Peptides via Metal Complex Chelation
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Solution Overview
Problem
Conventional methods for labeling peptides with F-18 are complex, require purification steps, and are not suitable for clinical settings due to the short half-life of F-18, necessitating efficient and simplified methods for high-specific-activity labeling without purification.
Innovation Solution
An in vitro method involving the formation of an F-18 metal complex by adding a metal such as aluminum, gallium, or indium to F-18, which is then attached to a chelating group on a molecule, such as a peptide, to create a stable F-18 labeled molecule for imaging without the need for purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional F-18 labeling methods are used, then peptides can be labeled with F-18, but the process requires purification steps and is too complex for clinical settings
Solution Approach 1:
The invention extracts and removes the purification step from the conventional labeling process by using a no-carrier-added F-18 labeling kit that produces sufficiently pure product directly, eliminating the need for separate purification equipment and procedures while maintaining clinical applicability
Solution Approach 2:
The labeling kit is designed to be universally applicable to various peptides containing appropriate functional groups, providing a single multi-functional solution that combines labeling and purification capabilities in one standardized protocol suitable for clinical settings
2Productivity
If conventional F-18 labeling methods are used, then peptides can be labeled, but the process is time-consuming and not suitable for the short half-life of F-18
Solution Approach 1:
The kit is prepared in advance with all necessary reagents pre-configured and the labeling protocol is optimized to proceed rapidly without intermediate purification steps, allowing the entire process to be completed within the short F-18 half-life window
Solution Approach 2:
The invention skips the time-consuming purification step by using a labeling approach that produces sufficiently pure product directly, rushing through the essential labeling reaction and eliminating non-essential intermediate steps to match the rapid decay timeline of F-18
3Measurement precision
If high specific activity is required for clear imaging, then sufficient photons can be obtained, but conventional methods produce lower specific activity due to purification requirements
Solution Approach 1:
The invention uses a specialized chelating agent or labeling reagent as an intermediary that enables direct attachment of F-18 to the peptide with high efficiency and selectivity, producing high specific activity product without requiring purification to remove unlabeled peptide
Solution Approach 2:
The labeling conditions are optimized with specific pH, temperature, and reagent concentrations that maximize the labeling efficiency and specific activity, changing the reaction parameters to favor complete labeling and eliminate the need for purification while ensuring imaging-quality specific activity
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
This method allows for the creation of F-18 labeled peptides with high specific activity and stability, enabling efficient imaging without the complexity and time-consuming purification steps of existing methods, suitable for clinical use.
Implementation Method 1
activating the F-18 by addition of a metal to form an F-18 metal complex
Implementation Method 2
attaching the F-18 metal complex to a chelating group on the molecule
Data Source
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AI summary
The present application discloses compositions and methods of synthesis and use of F-18 labeled molecules of use, for example, in PET imaging techniques. In particular embodiments, the labeled molecules may be peptides or proteins, although other types of molecules including but not limited to aptamers, oligonucleotides and nucleic acids may be labeled and utilized for such imaging studies. In preferred embodiments, the F-18 label may be conjugated to a targeting molecule by formation of a metal complex and binding of the F-18-metal complex to a chelating moiety, such as DOTA, NOTA, DTPA, TETA or NETA. In other embodiments, the metal may first be conjugated to the chelating group and subsequently the F-18 bound to the metal. In other preferred embodiments, the F-18 labeled moiety may comprise a targetable conjugate that may be used in combination with a bispecific or multispecific antibody to target the F-18 to an antigen expressed on a cell or tissue associated with a disease, medical condition, or pathogen. Exemplary results show that F-18 labeled targetable conjugate peptides are stable in human serum at 37°C for several hours, sufficient time to perform PET imaging analysis.