Modified Citrate Buffer Dissociates Analyte Complexes

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Solution Overview

Problem

Existing immunoassays face challenges in accurately quantifying total analyte concentrations in biological samples due to interference from soluble targets, leading to underestimation and compromised pharmacokinetic profiles, often requiring pre-treatment that introduces variability and sample loss.

Innovation Solution

A unique acidic dissociation buffer, specifically a modified citrate buffer with citrate-HCl and polysorbate-20, is used to dissociate analyte complexes with interfering substances in a single step ligand binding assay, allowing for accurate detection and quantification of total analyte without pre-treatment, utilizing components like capture and detection antibodies in an ELISA format.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pre-treatment is applied to remove interfering substances, then measurement precision is improved, but loss of substance and loss of time increase

Engineering Contradiction:
Improveaccuracy of analyte quantificationVSAvoidsample loss
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The interfering substance (soluble target) is selectively removed from the sample matrix through specific binding to a capture reagent, allowing the analyte to remain in solution for accurate measurement without losing the analyte itself

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A capture reagent acts as an intermediary that selectively binds to the interfering substance, separating it from the analyte of interest and enabling accurate measurement without direct sample loss

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If pre-treatment is applied to remove interfering substances, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveaccuracy of analyte quantificationVSAvoidassay procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The removal of interfering substances and the detection of analyte are combined into a single integrated assay step, eliminating separate pre-treatment stages and simplifying the overall procedure while maintaining measurement precision

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The assay reagents are designed to perform multiple functions simultaneously - capturing interfering substances, releasing analyte, and enabling detection - thereby reducing procedural complexity while maintaining accuracy

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If conventional immunoassay is used, then ease of operation is maintained, but measurement precision deteriorates due to interference

Engineering Contradiction:
Improveassay simplicityVSAvoidaccuracy of analyte quantification
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

A capture reagent is introduced as an intermediary component that selectively binds interfering substances, allowing the simple immunoassay format to maintain ease of operation while achieving accurate measurement by eliminating interference

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The assay conditions are modified by introducing specific reagents and conditions that change the binding parameters, allowing interfering substances to be selectively captured while maintaining the overall simplicity of the immunoassay procedure

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

This approach effectively nullifies interference from soluble targets, enabling precise quantification of analytes like trastuzumab in the presence of HER2-ECD, maintaining assay simplicity and reducing variability, with optimal results at pH 3.5, thereby improving the accuracy of pharmacokinetic profiles.

Implementation Method 1

a method of disassociating complex formed by interaction of analyte and at least one interfering substance as target for the analyte in a biological sample, said method comprising act of providing modified citrate buffer to the biological sample for disassociating the complex

Methodology Applied
Scientific EffectAcidic dissociation:

Data Source

PatentEP2815238B1A process for detection and optional quantification of an analyte
Publication Date: 2020.04.08 BIOCON LTD
  • EP2815238B1 patent drawingFigure 1A~1B
  • EP2815238B1 patent drawingFigure 2

AI summary

The present disclosure relates to a process for detecting and optionally quantifying an analyte in a sample in the presence of a soluble target of the analyte. The soluble target forms a complex with the analyte and thus may interfere in determining the total analyte concentration. The process of the present invention utilizes a unique modified citrate buffer for diluting the sample containing the analyte and the soluble target which in turn helps in dissociating the analyte-soluble target complex, thereby enabling the process of the disclosure to detect and optionally quantify measure the analyte accurately.