Hydrophilic SiFA-PSMA Radiopharmaceuticals for Better Biodistribution

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Solution Overview

Problem

Existing silicon-fluoride acceptor (SiFA) radiopharmaceuticals face a significant hydrophobicity issue, leading to unspecific binding in non-target tissues and poor biodistribution, which has not been satisfactorily addressed in prior art.

Innovation Solution

A ligand-SiFA conjugate compound is developed, incorporating a hydrophilic moiety to balance the hydrophobicity, comprising a ligand for prostate-specific membrane antigen (PSMA) binding and a silicon-fluoride acceptor (SiFA) for 18F labeling, with a hydrophilic linker to improve pharmacokinetic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If silicon-fluoride acceptor (SiFA) radiopharmaceuticals are used for PSMA targeting, then diagnostic and therapeutic efficacy is improved, but hydrophobicity increases leading to unspecific binding in non-target tissues

Engineering Contradiction:

Improvediagnostic and therapeutic efficacyVSAvoidunspecific binding in non-target tissues

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by introducing a hydrophilic moiety specifically at the linker region between the ligand and SiFA, while maintaining the hydrophobic SiFA group intact for its radiolabeling function. This localized modification creates a amphiphilic structure where the hydrophilic portion reduces unspecific binding in non-target tissues while the hydrophobic SiFA portion maintains its targeting and radiolabeling efficacy.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent creates a composite radiopharmaceutical structure combining hydrophobic SiFA group with hydrophilic linker moiety. This composite approach allows the molecule to exhibit both hydrophobic characteristics (for PSMA targeting and radiolabeling) and hydrophilic characteristics (for reduced unspecific binding and improved biodistribution), effectively resolving the contradiction between efficacy and unspecific binding.

Inventive Principle:

Principle #40Composite materials

2Reliability

If silicon-fluoride acceptor (SiFA) radiopharmaceuticals are used for PSMA targeting, then diagnostic and therapeutic efficacy is improved, but biodistribution deteriorates due to high hydrophobicity

Engineering Contradiction:

Improvediagnostic and therapeutic efficacyVSAvoidbiodistribution

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent modifies the local quality of the radiopharmaceutical by introducing a hydrophilic linker moiety that specifically addresses the biodistribution issue without affecting the core SiFA radiolabeling functionality. This localized hydrophilic modification improves blood circulation and tissue penetration while maintaining target specificity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the physicochemical parameters of the radiopharmaceutical by incorporating a hydrophilic moiety, which alters the overall hydrophobicity-hydrophilicity balance. This parameter change improves biodistribution characteristics including blood half-life, tissue penetration, and renal clearance, while preserving the diagnostic and therapeutic efficacy mediated by the SiFA group.

Inventive Principle:

Principle #35Parameter changes

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 compound achieves improved biodistribution and reduced unspecific binding, enhancing diagnostic and therapeutic efficacy for prostate cancer by targeting PSMA effectively.

Implementation Method 1

which SiFA moiety can be labeled with 18F by isotopic exchange of 19F by 18F

Methodology Applied

Scientific EffectIsotopic exchange:

Implementation Method 2

which SiFA moiety can be labeled with 18F by nucleophilic substitution of OH by 18F

Methodology Applied

Scientific EffectNucleophilic substitution:

Implementation Method 3

RL is a ligand moiety which is capable of binding to prostate-specific membrane antigen (PSMA)

Methodology Applied

Scientific EffectMolecular binding:

Data Source

PatentUS12576169B2Silicon-fluoride acceptor substituted radiopharmaceuticals and precursors thereof

Publication Date: 2026.03.17 TECHNISCHE UNIVERSITAT MUNCHEN

AI summary

A ligand-SiFA conjugate compound represented by formula (1) wherein: RL is a ligand moiety which is capable of binding to prostate-specific membrane antigen (PSMA); RSiFA is a silicon-fluoride acceptor (SiFA) moiety which can be labeled with 18F or which is labeled with 18F; L is a linking moiety; RH is a hydrophilic moiety which comprises (i) a linear or branched sequence of 2 to 10 hydrophilic amino acid units AH, each of which is independently derived from a natural or non-natural amino acid carrying a hydrophilic side chain, and optionally one amino acid unit AN derived from a natural or non-natural amino acid which is devoid of a hydrophilic side chain, wherein the hydrophilic amino acid units and, if present, the unit AN, are bound to each other via a direct covalent bond or via a coupling unit; and which optionally further comprises (ii) one or more hydrophilic residues RT, each of which may be bound to an amino group, a carboxylic acid group, or to a hydrophilic side chain of an amino acid unit; or a pharmaceutically acceptable salt thereof.