TSPO Radiotracer Binding Specificity and Kinetics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current TSPO radiotracers, such as 11C-PK11195, have limitations including short half-life, high non-specific binding, and sensitivity to the rs6971 genetic polymorphism, which affects their clinical utility in imaging inflammation and other diseases.
Innovation Solution
Development of novel compounds, specifically radiolabeled TSPO binders like 18F-LW223, which are insensitive to the rs6971 polymorphism, exhibit high affinity for TSPO, and have favorable kinetics and dosimetric profiles, enabling effective clinical use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 11C-PK11195 is used as a TSPO radiotracer, then TSPO binding can be detected, but the short half-life of the radioisotope limits clinical routine dissemination and requires onsite cyclotron facilities
Solution Approach 1:
The patent changes the radioisotope from 11C (20 min half-life) to 18F (110 min half-life), fundamentally altering the temporal parameter of the radiotracer. This parameter change enables longer imaging windows and eliminates the need for onsite cyclotron facilities, while maintaining TSPO binding detection capability through the fluorine-labeled compound structure
2Reliability
If 11C-PK11195 is used as a TSPO radiotracer, then TSPO binding can be detected, but high non-specific binding reduces imaging specificity
Solution Approach 1:
The patent introduces a fluorine-18 labeled fluoromethyl group at a specific position on the quinoline ring structure. This localized chemical modification at a specific molecular site enhances the affinity and specificity for TSPO binding, thereby reducing non-specific binding while maintaining detection reliability
3Reliability
If second generation radiotracers are used, then improved binding characteristics are achieved, but sensitivity to the rs6971 genetic polymorphism causes 10% of population to be unimageable
Solution Approach 1:
The patent identifies and isolates the critical binding interaction site on the quinoline ring by segmenting the molecular structure. By placing the fluorine-18 label at a specific position (position 3) on the quinoline ring, the compound achieves high affinity binding that is independent of the rs6971 polymorphism, thereby maintaining population applicability while improving binding characteristics
4Reliability
If 11C-PK11195 is used as a TSPO radiotracer, then TSPO binding can be detected, but the short half-life requires complex logistics and reduces clinical utility
Solution Approach 1:
The patent changes the radioisotope half-life parameter from 20 minutes to 110 minutes by using fluorine-18. This parameter change fundamentally simplifies the logistics by eliminating the requirement for onsite cyclotron facilities and enabling pre-synthesis and transport of the radiotracer, thereby reducing operational complexity while maintaining detection reliability
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 new TSPO radiotracers, such as 18F-LW223, demonstrate specific uptake consistent with TSPO expression, target engagement confirmed by blocking studies, and favorable pharmacokinetic properties, making them suitable for clinical imaging applications.
Implementation Method 1
The present invention provides compounds for use in binding to TSPO, methods for preparing those compound, methods for binding the compounds to TSPO, and methods for detecting the compound bound to TSPO
Implementation Method 2
The new TSPO radiotracers, such as 18F-LW223, demonstrate specific uptake consistent with TSPO expression
Data Source
AI summary
The invention provides a compound of formula (I), and salts, solvates and radiolabelled forms thereof, together with complexes of the compound of formula (I) with TSPO, and methods for forming such complexes, and methods for detecting the compound of formula (I), such as in complex with TSPO.