GBS Polysaccharide-Protein Conjugate Purification With Hydroxyapatite

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Solution Overview

Problem

Existing methods are inefficient in producing and purifying polysaccharide-protein conjugates, particularly for Group B Streptococcus (GBS) capsular polysaccharides, leading to high levels of free polysaccharide and carrier protein in the final product, which affects the immunogenicity and yield of the conjugates.

Innovation Solution

The method involves sizing the polysaccharides to a specific molecular weight range and using hydroxyapatite chromatography to separate conjugates from free polysaccharide and carrier protein, allowing for a more efficient purification process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional purification methods are used for polysaccharide-protein conjugates, then the purification process is simple, but the final product contains high levels of free polysaccharide and carrier protein which reduces immunogenicity and yield

Engineering Contradiction:

Improvepurity of conjugate productVSAvoidyield of conjugate product

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies parameter changes by utilizing the specific binding properties of hydroxyapatite chromatography under controlled conditions. The conjugate binds to hydroxyapatite while free polysaccharide does not, enabling selective separation. This parameter-based separation approach achieves high purity without sacrificing yield, as the conjugate can be recovered intact from the column after washing away contaminants.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If conventional purification methods are used for polysaccharide-protein conjugates, then the process is straightforward, but the amount of free polysaccharide and carrier protein in the final product remains high

Engineering Contradiction:

Improvepurity of conjugate productVSAvoidpresence of free polysaccharide and carrier protein

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent uses hydroxyapatite as an intermediary medium for purification. The hydroxyapatite column acts as a mediator that selectively binds the conjugate while allowing free polysaccharide to pass through in the flow-through fraction. This intermediary approach enables highly effective separation, removing harmful free components while preserving the conjugate for recovery.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If hydroxyapatite chromatography is used to separate conjugates from free polysaccharide and carrier protein, then the purity and yield of conjugates increase, but the chromatography process adds complexity to the production method

Engineering Contradiction:

Improvepurity of conjugate productVSAvoidcomplexity of purification process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical separation methods with a biochemical affinity-based separation using hydroxyapatite chromatography. Instead of relying on physical properties like size or density that would require complex equipment, the method uses specific molecular binding interactions between the conjugate and hydroxyapatite, simplifying the overall process while achieving superior purification results.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If hydroxyapatite chromatography is used to separate conjugates from free polysaccharide and carrier protein, then the yield of conjugates increases, but the process time and steps increase

Engineering Contradiction:

Improveyield of conjugate productVSAvoidpurification process time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent implements continuous useful action by designing a chromatography process where the conjugate binds to hydroxyapatite during loading, contaminants are washed away continuously, and the conjugate is then eluted in a single step. This continuous process minimizes idle time and maintains productive action throughout, achieving high yield without excessive time loss compared to batch purification methods.

Inventive Principle:

Principle #20Continuity of useful action

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 reduces the amount of free polysaccharide and carrier protein in the final product, maintaining immunogenicity and increasing the yield of the conjugates, particularly for GBS serotypes Ia, Ib, and II, while allowing reuse of the free carrier protein.

Implementation Method 1

carrying out a chromatography step by contacting the mixture with hydroxyapatite under conditions wherein the conjugate binds to the hydroxyapatite but free polysaccharide does not

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS12521443B2Conjugate production

Publication Date: 2026.01.13 GLAXOSMITHKLINE BIOLOGICALS SA

AI summary

This application relates to methods for the production of polysaccharide antigen-carrier protein conjugates, in particular conjugates of Group B Streptococcus (GBS) capsular polysaccharide and a carrier protein, in particular CRM197. The methods comprise a hydroxyapatite chromatography step in order to separate the conjugate from free polysaccharide and free carrier protein.