Radiolabeled Compounds for Alpha-Synuclein PET Imaging

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Solution Overview

Problem

Current PET tracers are inadequate for imaging aggregates of α-synuclein (aSyn) in the brain, as they lack high affinity and selectivity for aSyn over other amyloid structures like Aβ and tau, and struggle to cross the blood-brain barrier effectively.

Innovation Solution

Development of radiolabeled compounds of formula I, where A is piperazinyl or hexahydropyrrolo[3,4-c]pyrrol-2(1H)-yl, B is phenyl, pyridinyl, piperazinyl, pyrimidinyl, or pyrazinyl, and R1 and R2 are various aryl and heteroaryl groups, labeled with radionuclides like 3H, 11C, or 18F, which demonstrate high affinity for aSyn aggregates and appropriate properties for brain imaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If current PET tracers are used for imaging aSyn aggregates, then imaging capability is provided, but affinity and selectivity for aSyn over other amyloid structures is insufficient

Engineering Contradiction:
Improveaffinity and selectivity for aSynVSAvoidimaging accuracy of aSyn
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent modifies specific regions of the tracer molecule (introducing fluorinated aromatic groups and specific heterocyclic structures at defined positions in the molecule) to enhance local interaction with aSyn aggregates while maintaining overall molecular stability and brain penetration capability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent systematically varies molecular parameters including fluorine substitution patterns, heterocyclic ring types, and linker chain lengths to optimize the balance between affinity for aSyn, selectivity against Aβ and tau, and ability to cross the blood-brain barrier

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If radiolabeled compounds are designed for high affinity to aSyn, then diagnostic accuracy improves, but ability to cross blood-brain barrier may be compromised

Engineering Contradiction:
Improvediagnostic accuracyVSAvoidblood-brain barrier penetration
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent optimizes molecular weight, lipophilicity, and hydrogen bonding capacity by selecting specific fluorinated aromatic groups and heterocyclic structures, achieving a balance that allows both high aSyn affinity and effective blood-brain barrier penetration

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs specific molecular scaffolds (piperazinyl and hexahydropyrrolo[3,4-c]pyrrol-2(1H)-yl groups) that act as intermediaries, facilitating both high-affinity binding to aSyn aggregates and efficient transport across the blood-brain barrier

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If selectivity for aSyn over Aβ and tau is enhanced, then specific imaging of aSyn is achieved, but tracer design complexity increases

Engineering Contradiction:
Improveselectivity for aSynVSAvoidtracer molecular structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces specific functional groups (fluorinated aromatics and heterocycles) at particular positions on the molecular scaffold to create localized high-affinity interaction sites for aSyn, achieving selectivity without requiring complete redesign of the entire molecule

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent combines multiple structural elements (fluorinated aromatic groups, heterocyclic rings, and specific linkers) into a composite molecular structure that collectively provides aSyn selectivity while maintaining reasonable molecular complexity

Inventive Principle:
Principle #40Composite materials

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

These radiolabeled compounds enable effective PET imaging of aSyn aggregates in the brain, improving diagnostic accuracy for Parkinson's disease, allowing for non-invasive monitoring of aSyn pathology, and facilitating the assessment of anti-aSyn therapy efficacy.

Implementation Method 1

either A, B, R1, or R2, is labeled with a radionuclide selected from 3H, 11C and 18F

Methodology Applied
Scientific EffectRadioactive decay: Radioactive Decay

Implementation Method 2

PET, a nuclear medical imaging modality, is ideally suited to produce three-dimensional images that provide important information on the distribution of a biological target

Methodology Applied
Scientific EffectPET imaging: Tomography

Data Source

PatentEP3728234B1Radiolabeled compounds
Publication Date: 2025.05.14 F HOFFMANN LA ROCHE & CO AG
  • EP3728234B1 patent drawingFigure 1~2
  • EP3728234B1 patent drawingFigure 3
  • EP3728234B1 patent drawingFigure 4

AI summary

The present invention relates to radiolabeled compounds of formula (I) wherein either A, B, R1, R2, is labeled with a radionuclide selected from 3H, 11C and 18F and its use for imaging alpha synuclein and/or Abeta deposits in mammals.