PSMA Imaging Agent Linker Composition for Low Background Uptake
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Solution Overview
Problem
Current PSMA imaging agents suffer from non-specific uptake and high background activity in organs like salivary glands and liver, leading to reduced sensitivity and potential toxicity in therapeutic applications due to hydrophobic interactions and bulky linkers in existing tracer designs.
Innovation Solution
Development of PSMA-specific agents with negatively charged linkers and optimized linker regions, incorporating amino acid chains and organic spacer groups to enhance binding affinity and reduce non-specific uptake, allowing for improved imaging and therapeutic efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hydrophobic linkers and bulky structures are used in PSMA imaging agents, then binding affinity to PSMA is improved, but non-specific uptake in organs like salivary glands and liver increases
Solution Approach 1:
The patent changes the chemical parameter of the linker from hydrophobic to negatively charged (hydrophilic). This parameter change resolves the contradiction by maintaining binding affinity through the urea moiety while the charged linker reduces non-specific hydrophobic interactions with off-target organs, thereby decreasing non-specific uptake.
Solution Approach 2:
The patent creates a composite structure combining a hydrophilic negatively charged linker with a hydrophobic aromatic urea moiety. This composite design allows the hydrophobic urea to bind specifically to PSMA while the hydrophilic linker prevents non-specific interactions, resolving the contradiction between binding affinity and non-specific uptake.
2Reliability
If long slender hydrophobic linkers are used to connect imaging groups to PSMA binding moieties, then binding capability is improved, but background activity in non-PSMA expressing organs increases
Solution Approach 1:
The patent changes the physical-chemical parameter of the linker from hydrophobic to hydrophilic by introducing negative charges. This resolves the contradiction by maintaining the linker's length and connectivity function while eliminating hydrophobic interactions that cause background activity in non-PSMA expressing organs.
3Adaptability or versatility
If existing PSMA imaging agents are used for therapeutic applications, then targeting capability is achieved, but toxicity increases due to non-specific uptake
Solution Approach 1:
The patent changes the charge parameter of the linker to negative, which maintains targeting capability through the PSMA-binding urea moiety while reducing non-specific uptake in off-target organs. This reduces the harmful effects/toxicity in non-target tissues while preserving the therapeutic targeting function.
Data Source
AI summary
A PSMA-specific agent comprising a compound according to Formula I or Formula II: wherein S1 is absent or is an organic spacer group comprising 3-10 carbons; A is an amino acid chain comprising 1 to 5 amino acids wherein at least one of the amino acids is selected from glutamic acid and aspartic acid; S2 is absent or is an organic spacer group comprising 1 to 15 carbons and/or 0 to 2 amino acids; I1 is an imaging group; and I2 is absent or is an imaging group. The PSMA-specific agents can be used to image PSMA within a tissue region and/or for the treatment of a cancer, such as prostate cancer.