Purification Tag for Monoconjugate Isolation

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Solution Overview

Problem

Coupling reactions involving multi-functional reagents often result in a mixture of mono-, di-, and higher conjugates, making the isolation of specific conjugates, such as monomers, difficult due to small molecular weight differences between them.

Innovation Solution

The use of compounds with a tag moiety that includes a protecting group for thiol functional groups, which allows for the conjugation to high molecular weight entities like proteins, enabling the isolation of mono-, di-, and higher conjugates by exploiting the tag moiety's positive charge under aqueous conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If coupling reactions use multi-functional reagents, then the reaction efficiency and product diversity are improved, but the separation and isolation of specific conjugates becomes difficult

Engineering Contradiction:
Improvereaction efficiencyVSAvoidisolation of specific conjugates
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent introduces a purification tag as an intermediary component attached to the reagent. This tag serves as a mediator that enables selective purification of conjugates through specific interactions (such as affinity binding) with purification media, allowing the separation of mono-, di-, and higher conjugates that would otherwise be difficult to isolate due to their similar molecular weights.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs detection tags that provide optical or physical properties (such as fluorescence, absorbance, or charge) enabling the detection and differentiation of conjugates with different stoichiometries. These tags allow monitoring and identification of specific conjugate types during the reaction and purification process.

Inventive Principle:
Principle #32Color changes

2Device complexity

If the relative molecular weight difference between different types of conjugates is small, then the complexity of the reaction mixture is reduced, but the isolation of specific conjugates becomes difficult or impossible

Engineering Contradiction:
Improvecomplexity of reaction mixtureVSAvoidisolation of specific conjugates
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The purification tag acts as an intermediary that provides a distinct interaction mechanism for separation. Even when conjugates have similar molecular weights, the tag enables differentiation through specific binding affinities (e.g., streptavidin-biotin, antibody-antigen) or charge properties, allowing isolation of specific conjugate types despite the small molecular weight differences.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes changes in physical or chemical parameters of the tag (such as charge state, affinity binding constant, or optical properties) to enable separation. By exploiting these parameter differences introduced by the tag, the patent achieves isolation of specific conjugates that cannot be separated by conventional size-based methods alone.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If a tag moiety is conjugated to a protecting group, then the isolation of specific conjugates is enabled, but the tag moiety is removed upon removal of the protecting group and is thus not present in the final compound

Engineering Contradiction:
Improveisolation of specific conjugatesVSAvoidpresence of tag in final compound
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The purification tag is designed as a temporary intermediary that facilitates the purification process but is intentionally removed before the final product is obtained. The tag enables the isolation of pure monoconjugates during the process, and its subsequent removal ensures the final compound is free of purification artifacts, achieving both high purity and operational simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a strategy where the purification tag is discarded after serving its purification function. The tag is removed along with the protecting group in a deprotection step, and the purified conjugate is recovered without the tag. This approach allows the tag to be used as a temporary tool for isolation without contaminating the final product.

Inventive Principle:
Principle #34Discarding and recovering

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

This approach allows for the effective isolation of specific conjugates, such as monoconjugates, from mixed conjugate samples by utilizing the tag moiety's properties for purification, ensuring high purity and separation.

Implementation Method 1

T is a tag moiety comprising at least one positive charge under aqueous conditions at pH 3 to 7 provided by an ammonium, phosphonium or tertiary amine

Methodology Applied
Scientific EffectCharge-based separation: Ion Exchange

Data Source

PatentEP3054981B1Protecting group comprising a purification tag
Publication Date: 2020.07.29 ASCENDIS PHARM AS
  • EP3054981B1 patent drawingFigure 1
  • EP3054981B1 patent drawingFigure 2
  • EP3054981B1 patent drawing

AI summary

The present invention relates to compounds comprising a protecting group moiety-tag moiety conjugate, a method of purification and monoconjugates obtained from such method of purification.