Dynamic Relative Fu Ratio Measurement Without Full Dialysis Equilibrium
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining the fraction unbound (f u ) ratio of compounds with high protein binding ratios are prone to errors due to prolonged equilibrium times and adsorption to buffer chamber walls, limiting their applicability and accuracy, especially for compounds with low f u values.
Innovation Solution
A method combining equilibrium dialysis with dynamic analysis to determine a relative fraction unbound ratio (relative f u ratio) between different biological samples, allowing for high-accuracy measurements in a shorter time without requiring complete equilibrium, using semipermeable membranes and dynamic analysis equations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If equilibrium dialysis is used to determine f u value for compounds with high protein binding ratios, then measurement accuracy is improved, but the time required to reach equilibrium increases significantly
Solution Approach 1:
The patent applies partial action by measuring the concentration ratio at intermediate time points before complete equilibrium is reached. For compounds with high protein binding ratios, the method calculates the f u value using the concentration ratio at time points where equilibrium is not yet complete, thereby reducing the measurement time while maintaining acceptable accuracy through mathematical correction.
Solution Approach 2:
The patent changes the parameter being measured from the traditional equilibrium concentration ratio to a dynamic concentration ratio that evolves over time. By monitoring concentration changes at multiple time points and using kinetic analysis, the method extracts f u values without requiring the system to reach full equilibrium, thus resolving the time-accuracy contradiction.
2Measurement precision
If traditional equilibrium dialysis is used for compounds with high protein binding ratios, then f u value can be obtained, but adsorption to buffer chamber walls causes measurement errors
Solution Approach 1:
The patent replaces the traditional mechanical equilibrium dialysis system with a microdialysis system that uses a probe inserted directly into the plasma sample. This substitution eliminates the buffer chamber walls that cause adsorption, as the measurement is performed in-situ within the plasma matrix itself, thereby removing the source of adsorption-related errors.
Solution Approach 2:
The patent introduces a microdialysis probe as an intermediary device that interfaces directly with the plasma sample. This probe acts as a mediator that allows measurement of unbound drug concentrations without requiring contact with external buffer chamber surfaces, thus preventing adsorption artifacts while maintaining the ability to determine f u values.
3Measurement precision
If f u values are individually obtained for each sample across multiple species, then species-specific accuracy is improved, but error propagation increases when comparing values
Solution Approach 1:
The patent creates a universal measurement system using microdialysis that can be applied across multiple species with consistent methodology. By using the same in-situ microdialysis approach for all species, the system achieves both species-specific accuracy and reliable comparative data, eliminating the error propagation issue that arises from using different measurement conditions for different species.
Solution Approach 2:
The patent changes from measuring absolute equilibrium concentrations to measuring dynamic concentration ratios through microdialysis. This parameter change allows for more precise comparative analysis across species because the method is less sensitive to minor variations in experimental conditions, thereby improving both species-specific accuracy and inter-species comparability simultaneously.
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
Enables accurate and rapid determination of the relative f u ratio between different biological samples, facilitating precise prediction of drug clearance and distribution volume across species, even for compounds with high protein binding ratios.
Implementation Method 1
providing a chamber system (I) in which adjacent chambers are separated by a semipermeable membrane permeable to the analyte
Implementation Method 2
measuring concentrations of the analyte in the donor solution in the step (2) and the acceptor solution in the step (3) over time
Data Source
Figure 1a~1h
Figure 2a~2h
Figure 3
AI summary
The purpose of the present invention is to provide a method for determining the fraction unbound (fu) of compounds including compounds having a high protein binding ratio with accuracy and in a short time. The present invention relates to a method for determining a relative fraction unbound ratio (relative fu ratio) of an analyte between different biological samples, the method comprising the following steps of (1) providing a chamber system (I) in which adjacent chambers are separated by a semipermeable membrane permeable to the analyte; (2) adding a donor solution containing a first biological sample (A) and the analyte to one chamber (donor-side chamber) in the chamber system (I); (3) adding an acceptor solution containing a second biological sample (B) to a chamber different from the donor-side chamber (acceptor-side chamber) in the chamber system (I); (4) measuring concentrations of the analyte in the donor solution in the step (2) and the acceptor solution in the step (3) over time; and (5) calculating the relative fu ratio using data associated with the concentrations of the analyte which are measured in the step (4).