18F-Labeled PSMA Inhibitors for Accurate PET Cell Imaging
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Solution Overview
Problem
Existing cancer diagnosis and therapy using antibodies are limited by immunogenicity, poor vascular permeability, and decreased cell-surface labeling due to large antibody binding, while the enzymatic activity of prostate-specific membrane antigen (PSMA) has been largely unexplored for diagnostic and therapeutic strategies.
Innovation Solution
Development of small-molecule PSMA inhibitors, specifically 18F-labeled compounds with high affinity and specificity, for detecting and imaging PSMA-presenting cells, such as prostate cancer cells, to monitor and stratify patients for appropriate therapeutic agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antibody-based methods are used for cancer detection, then specificity to PSMA can be achieved, but immunogenicity and poor vascular permeability limit effectiveness
Solution Approach 1:
The patent replaces long-lived antibodies with short-lived small molecule inhibitors that can be rapidly cleared from the body. These small molecules serve as disposable imaging agents that provide the necessary diagnostic information before being eliminated, avoiding the immunogenicity and persistence issues of antibody-based approaches
Solution Approach 2:
The patent substitutes the biological antibody system with a small molecule chemical system. Instead of relying on the immune system's antibody production and binding mechanisms, the invention uses synthetic small molecules that bind to PSMA through non-immunological interactions, thereby eliminating immunogenicity while maintaining target specificity
2Reliability
If large antibodies are used for cell-surface targeting, then PSMA binding can be achieved, but poor vascular permeability and decreased cell-surface labeling result
Solution Approach 1:
The patent segments the imaging function from the large antibody structure, using small molecule inhibitors that can penetrate blood vessels and reach cell surfaces more effectively. The small molecules are divided into discrete chemical entities that can navigate the vascular system and bind to PSMA without the steric hindrance of large antibody structures
Solution Approach 2:
The patent uses small molecule inhibitors as temporary, disposable imaging agents that can rapidly distribute through the vascular system and bind to cell surface targets. These small molecules provide the necessary imaging function during their brief circulation lifetime without the persistence and size limitations of antibodies
3Reliability
If antibody-based imaging is used, then PSMA detection can be achieved, but large antibody binding creates a barrier for subsequent binding at neighboring sites
Solution Approach 1:
The patent uses small molecule inhibitors that occupy minimal space on the cell surface compared to large antibodies. This segmentation of the binding interface allows multiple small molecules to bind to neighboring PSMA sites simultaneously or sequentially, enabling multi-binding capability and repeated imaging without steric blocking
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 small-molecule PSMA inhibitors effectively target and image PSMA-expressing cells, providing accurate diagnostic imaging and potential therapeutic monitoring without the limitations of traditional antibody-based methods.
Implementation Method 1
R1 is an 18F-labeled phenyl or pyridyl
Data Source
AI summary
Compounds as defined herein are provided which are useful in (1) diagnostic methods for detecting and/or identifying cells presenting PSMA; and (2) methods for preparing the compounds.