Multiwell Lipophilicity Assay Using Membrane-Based Phase Separation

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Solution Overview

Problem

Existing methods for determining lipophilicity of compounds are time-consuming and inefficient, particularly for low-soluble compounds, and require lengthy incubation times and solvent separation processes.

Innovation Solution

A method using a multiwell plate with a lipophilic membrane and a liquid-tight barrier, where a non-polar solvent is added to the membrane, followed by an aqueous solution containing the test compound, allowing for direct determination of the compound's quantity after distribution equilibrium is reached, without the need for solvent separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the conventional shake-flask method is used to determine lipophilicity, then accurate measurement can be achieved, but the determination time becomes very long (only 2-5 compounds per day)

Engineering Contradiction:
Improvelipophilicity measurement accuracyVSAvoiddetermination speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The invention segments the lipophilicity determination process into multiple independent parallel measurements using a multiwell plate with 96 wells, allowing simultaneous determination of multiple compounds rather than sequential processing in the conventional shake-flask method

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a lipophilic membrane as an intermediary carrier that holds the non-polar solvent and facilitates phase separation, enabling direct measurement without manual solvent removal and extraction steps

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the assay system is incubated for 12 hours to reach distribution equilibrium, then accurate lipophilicity values can be obtained, but the determination time becomes excessively long

Engineering Contradiction:
Improvelipophilicity value accuracyVSAvoidincubation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The invention applies preliminary action by pre-coating the lipophilic membrane with non-polar solvent before adding the aqueous solution, creating optimized contact surfaces that accelerate the reaching of distribution equilibrium from 12 hours to approximately 2 hours

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention transitions from bulk liquid-liquid extraction to a membrane-based interfacial system, creating a large surface area contact between phases that dramatically speeds up the equilibrium process while maintaining measurement accuracy

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If solvent removal is required after the assay to measure compound concentration, then accurate measurement can be achieved, but the procedure becomes complex and time-consuming

Engineering Contradiction:
Improveconcentration measurement accuracyVSAvoidassay procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts the solvent removal step from the assay procedure by using a membrane system where the non-polar solvent remains bound to the membrane, automatically separating it from the aqueous phase where the compound concentration is measured, eliminating the need for manual solvent removal

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The membrane system performs self-service by automatically maintaining phase separation and preventing solvent mixing, eliminating the need for manual intervention in solvent removal and simplifying the overall procedure

Inventive Principle:
Principle #25Self-service

4Measurement precision

If conventional methods are used to determine lipophilicity of low soluble compounds, then measurement can be performed, but the results are unreliable and the process is inefficient

Engineering Contradiction:
Improvelipophilicity determination reliabilityVSAvoiddetermination efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The invention applies local quality by using a lipophilic membrane with specific surface properties that selectively interact with low soluble compounds, providing a localized environment optimized for their partitioning behavior and enabling reliable measurement that conventional bulk methods cannot achieve

Inventive Principle:
Principle #3Local quality

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 method significantly reduces determination time to 1.5 hours from 12 hours, facilitates easy handling, and accurately measures lipophilicity across a broad range, including low-soluble compounds, with improved exchange surface area for faster equilibrium.

Implementation Method 1

providing a multiwell plate, wherein the wells comprise at the bottom a lipophilic membrane

Methodology Applied
Scientific EffectPhase separation:

Implementation Method 2

determining the quantity of the test compound in the aqueous solution after a distribution equilibrium has been reached

Methodology Applied
Scientific EffectDistribution equilibrium:

Implementation Method 3

the bottom of the multiwell plate comprises a liquid tight barrier to seal the wells and to produce a liquid tight bottom of the multiwell plate

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Implementation Method 4

Lipophilicity is expressed either by log P (octanol-water Partition coefficient for neutral species) or log D (octanol-water Distribution coefficient for charged molecules)

Methodology Applied
Scientific EffectPartitioning:

Data Source

PatentEP4381272B1Multiwell plate lipophilicity assay
Publication Date: 2026.02.04 F HOFFMANN LA ROCHE & CO AG
  • EP4381272B1 patent drawingFigure 1~3
  • EP4381272B1 patent drawingFigure 4
  • EP4381272B1 patent drawing

AI summary

The present invention relates to a method for determining the lipophilicity of a test compound comprising the steps of: a) providing a multiwell plate, wherein the wells comprise at the bottom a lipophilic membrane and the bottom of the multiwell plate comprises a liquid tight barrier to produce a liquid tight bottom of the multiwell plate, b) adding a non-polar solvent to the lipophilic membranes in the wells of step a), c) adding an aqueous solution comprising the test compound to the wells of step b, and d) determining the quantity of the test compound in the aqueous solution after a distributionequilibrium has been reached.