Tetrafluoro Phenyl Ester for 18F Peptide Labelling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for preparing 18F-labelled peptides are time-consuming and difficult to automate, with existing reagents like N-succinimidyl-4-[18F]fluorobenzoate requiring multiple synthetic steps and introducing hydrophobicity that affects the biodistribution profile of the radiopharmaceuticals.
Innovation Solution
Development of 18F-labelled compounds with the 18F label attached ortho-to the pyridyl nitrogen, using a tetrafluoro phenyl ester system that allows for one-step labelling at near room temperature, enabling automation through cartridge-based purification and improving the hydrophilicity of the product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If N-succinimidyl-4-[18F]fluorobenzoate (SFB) is used for 18F-labelling of peptides, then the labelling can be achieved with existing reagents, but the preparation takes 3 synthetic steps plus HPLC purification making it difficult to automate and time-consuming
Solution Approach 1:
The invention segments the labelling process by using a pre-synthesized precursor compound (containing the pyridyl nitrogen and leaving group) that reacts directly with [18F]fluoride ion. This separates the complex SFB synthesis steps from the actual labelling step, allowing the labelling to occur in a single reaction step followed by simple cartridge purification, thus reducing preparation time while maintaining labelling effectiveness.
Solution Approach 2:
The invention applies preliminary action by pre-synthesizing the precursor compound with the appropriate pyridyl nitrogen and leaving group structure before the labelling step. This preliminary preparation of the precursor allows the actual 18F-labelling to proceed rapidly in one step without requiring the multiple synthesis steps needed for SFB, thereby reducing the time loss while ensuring reliable labelling.
2Reliability
If N-succinimidyl-4-[18F]fluorobenzoate (SFB) is used for 18F-labelling, then the labelling reaction can proceed, but the phenyl ring adds significant hydrophobicity to the product which adversely affects biodistribution profile
Solution Approach 1:
The invention applies local quality by modifying the molecular structure at the labelling site to use a pyridyl nitrogen-containing group instead of a phenyl ring. This localized structural change at the point of 18F attachment reduces the hydrophobicity of the final radiopharmaceutical product, improving its biodistribution profile while maintaining the ability to perform effective 18F-labelling through the pyridyl nitrogen's reactivity with [18F]fluoride.
3Reliability
If existing 18F-labelling reagents are used, then labelling can be achieved, but the process is difficult to automate which limits clinical preparation
Solution Approach 1:
The invention facilitates automation by using a cartridge-based purification system that discards impurities and recovers the labelled product in a single step. The precursor compound and reaction conditions are designed so that after the one-step labelling reaction, the mixture can be passed through a cartridges that automatically separate and recover the labelled peptide, eliminating the need for manual HPLC purification and enabling automated clinical preparation while maintaining labelling success.
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 approach facilitates rapid, chemoselective 18F introduction into peptides, enhancing the stability and biodistribution profile of the 18F-labelled products, making them more suitable for clinical use in Positron Emission Tomography (PET) imaging.
Implementation Method 1
the compounds of formula (I) and (Ia) can be 18F-labelled in one step, the labelling is fast at near room temperature
Implementation Method 2
the pyridine system is known to be more hydrophilic than the benzyl analogue and is therefore expected to add a positive impact on the biodistribution profile of the 18F-product
Implementation Method 3
the tetrafluoro phenyl ester has been found to be more stable during 18F-labelling than other active esters
Data Source
AI summary
The present invention relates to reagents and methods for [18F]-fluorination of biomolecules, particularly of peptides. The resultant 18F-labelled compounds are useful as radiopharmaceuticals, specifically for use in Positron Emission Tomography (PET).