Dynamic Analysis for Relative fu Ratio Measurement
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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 the relative fraction unbound ratio (relative f u ratio) between different biological samples, allowing for high-accuracy measurements in a short 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 the method can provide accurate measurements, but the time required to reach equilibrium state increases significantly
Solution Approach 1:
The patent applies dynamic analysis to the dialysis process by continuously monitoring concentration changes over time and using kinetic models to determine f u values. Instead of waiting for static equilibrium, the system analyzes the dynamic progression of dialysis to calculate binding parameters, thereby reducing the required time while maintaining measurement accuracy.
Solution Approach 2:
The patent changes the analytical approach from measuring final equilibrium concentrations to analyzing concentration-time profiles. By transforming the measurement parameter from static concentration ratio to dynamic concentration change rate, the system can extract f u values without requiring complete 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 values can be obtained, but adsorption to buffer chamber walls causes errors
Solution Approach 1:
The patent introduces a mathematical model as an intermediary between the dialysis process and the final measurement. The kinetic model accounts for and separates the adsorption component from the binding component, allowing the system to correct for wall adsorption effects and retrieve accurate f u values that would otherwise be contaminated by adsorption errors.
Solution Approach 2:
The patent replaces the purely physical/chemical equilibrium approach with a mathematical modeling approach. Instead of relying on the physical separation of bound and unbound drug at equilibrium, the system uses mathematical equations to deconvolve the complex processes of binding and adsorption, thereby eliminating the harmful effect of wall adsorption on measurement accuracy.
3Measurement precision
If equilibrium dialysis is performed for compounds with low f u values, then binding information can be obtained, but the process is highly susceptible to errors
Solution Approach 1:
The patent implements feedback through continuous monitoring of concentration changes during dialysis. By tracking the time-course data and comparing it against kinetic models, the system can iteratively refine its estimates of f u values and bound/unbound concentrations. This feedback mechanism reduces error susceptibility by using multiple data points and model constraints rather than relying on a single equilibrium measurement that is highly sensitive to small errors.
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 in humans by correcting data from one species to another.
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).