BCA-MSA Conjugates for Stable 68Ga Radiolabeling

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Solution Overview

Problem

Current radiopharmaceuticals for lymphatic system imaging, such as 99mTc-labeled colloids and 99mTc-HSA, face challenges including large particle size, instability, and inability to provide clear lymph node images, especially when using positron emission tomography (PET), which requires complex and expensive radionuclide production.

Innovation Solution

Development of bifunctional chelating agent (BCA) conjugates with mannosylated human serum albumin (MSA) for easy labeling with positron emitter 68Ga, providing stable and high-accumulation imaging in lymph nodes, liver, and spleen, along with a pharmaceutically compatible kit for convenient radiolabeling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If 99mTc-labeled colloids (antimony sulfur colloid, albumin nano colloid, sulfur colloid) are used for lymph node imaging, then lymph node detection is achieved, but particle size is too large causing slow uptake and requiring long labeling time

Engineering Contradiction:

Improvelymph node uptake speedVSAvoidparticle size

Core Design Contradiction:

SpeedVSVolume of moving object

Solution Approach 1:

The patent changes the particle size parameter by using human serum albumin (6-8 nm) instead of traditional colloids (10-200 nm), achieving rapid lymph node uptake while maintaining imaging capability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite radiopharmaceutical by conjugating mannosyl groups to human serum albumin, combining the beneficial properties of small particle size with mannose receptor binding capability for enhanced lymph node accumulation

Inventive Principle:

Principle #40Composite materials

2Productivity

If 99mTc-HSA is used for lymph node imaging, then rapid labeling and movement to lymph nodes is achieved, but contrast is low and uptake occurs in multiple lymph nodes not just sentinel nodes

Engineering Contradiction:

Improvelabeling speedVSAvoidimage contrast

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces mannose groups specifically to HSA, creating local binding sites that target sentinel lymph nodes through mannose receptor interaction, thereby improving image contrast and specificity without sacrificing labeling speed

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The mannose group acts as an intermediary between the radiopharmaceutical and mannose receptors on sentinel lymph node cells, enabling specific accumulation and improving detection precision

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If disulfide reduced MSA is prepared by treating with reducing agents for 99mTc labeling, then labeling is enabled, but the agent cannot be imaged by PET

Engineering Contradiction:

Improvelabeling capabilityVSAvoidimaging modality compatibility

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent changes the radionuclide parameter from 99mTc (gamma emitter) to 68Ga (positron emitter), enabling PET imaging capability while maintaining the disulfide reduced MSA conjugate structure and labeling feasibility

Inventive Principle:

Principle #35Parameter changes

4Measurement precision

If conventional radiopharmaceuticals are used, then lymph node imaging is achieved, but complex and expensive radionuclide production is required for PET

Engineering Contradiction:

Improveimaging qualityVSAvoidradionuclide production complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses 68Ga, a radionuclide that can be generated from a generator system (parent 68Ge decaying to 68Ga), replacing the need for expensive cyclotron-based production, thereby reducing device complexity and cost while maintaining PET imaging quality

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 BCA-MSA conjugates enable convenient and stable labeling with 68Ga, achieving excellent immune system imaging, including lymph nodes, with high accumulation and stability, suitable for PET imaging, and are compatible for direct human injection.

Implementation Method 1

conjugates of bifunctional chelating agent (BCA) and mannosyl human serum albumin (MSA)... stable complexes with 68Ga

Methodology Applied

Scientific EffectChelation:

Implementation Method 2

positron emitter 68Ga... imaging by positron emission tomography (PET)

Methodology Applied

Scientific EffectPositron emission: Radioactive Decay

Implementation Method 3

MSA can strongly bind with mannose receptor... high accumulation in the lymph nodes, liver, and spleen

Methodology Applied

Scientific EffectReceptor binding:

Data Source

PatentUS8911706B2Complex of bifunctional chelating agent and mannosyl human serum albumin

Publication Date: 2014.12.16 SEOUL NATIONAL UNIVERSITY R&DB FOUNDATION

AI summary

The present invention is about bifunctional chelating agents (BCA) conjugated mannosyl human serum albumin (MSA) and its radioisotope labeled compounds for imaging immune system such as macrophages, Kupffer cells, reticuloendothelial system (RES), and lymphatic system. The present invention comprises BCA-MSA conjugates, their radiolabeled compounds, and kits for radiolabeing. The present invention improved radiolabeling procedure, showed higher lymphatic system uptake, and enabled image by positron emission tomography (PET).