Antibody-Drug Conjugate DAR Assessment via UPLC and Slope Spectroscopy
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Solution Overview
Problem
Current methods for assessing the drug-to-antibody ratio (DAR) in antibody-drug conjugates (ADCs) are limited by low throughput and require sample dilution, leading to errors and inefficiencies in formulation screening studies.
Innovation Solution
The use of size exclusion chromatography (UPLC) and slope spectroscopy methods to determine DAR, which allow for high-throughput analysis without sample dilution, using equations derived from the Beer-Lambert law to calculate the ratio of antibody and drug concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional UV-Vis spectroscopy is used to measure DAR, then the measurement can be performed with simple equipment, but the throughput is low and sample dilution is required
Solution Approach 1:
The patent segments the DAR measurement process into distinct spectral regions (antibody region at 280 nm and drug region at 252 nm), allowing simultaneous measurement of both components without sample dilution. This segmentation enables high-throughput analysis by eliminating the need for serial dilutions while maintaining measurement accuracy.
Solution Approach 2:
The patent transitions from traditional single-wavelength or limited-wavelength UV-Vis measurements to a multi-wavelength spectral analysis approach. By utilizing the full spectral information at multiple wavelengths (252 nm for drug, 280 nm for antibody), the method increases throughput without requiring sample dilution, effectively adding a dimensional aspect to the measurement.
2Measurement precision
If sample dilution is performed to enable UV-Vis DAR measurement, then the measurement can be performed, but errors are introduced and throughput is reduced
Solution Approach 1:
The patent performs preliminary spectral characterization to determine the specific absorption coefficients of the antibody and drug at their respective wavelengths (280 nm and 252 nm). This preliminary action enables direct calculation of DAR from undiluted sample measurements, eliminating the need for subsequent dilution steps and associated errors while maintaining high throughput.
Solution Approach 2:
The patent changes the measurement parameters by utilizing the differential absorption characteristics of the antibody and drug at different wavelengths. By measuring absorbance at 280 nm (where antibody absorbs) and 252 nm (where drug absorbs), the method enables direct DAR calculation from undiluted samples, improving both precision and throughput.
3Productivity
If high-throughput DAR assessment is implemented, then productivity increases, but measurement reliability may be compromised
Solution Approach 1:
The patent incorporates feedback through the use of predetermined absorption coefficients that are established from spectral characterization. These coefficients serve as reference values that enable reliable DAR calculations from undiluted sample measurements, maintaining measurement reliability while achieving high throughput through automated calculation.
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
These methods provide more reliable and precise DAR measurements, overcoming throughput limitations and enabling accurate analysis without sample dilution, thus improving the assessment of ADC product quality and stability.
Implementation Method 1
applying a sample comprising an antibody-drug conjugate to a size-exclusion chromatography matrix
Implementation Method 2
The basis for this analysis is the Beer-Lambert law, a direct proportional relationship between the absorbance and concentration of a substance
Implementation Method 3
A=εcl, where A is the absorbance, ε is the extinction coefficient (a physical constant of the substance), l is the path length through the cell containing the analyte, and c is the concentration
Data Source
AI summary
The present disclosure provides methods of assessing DAR of ADC products that provide advantages over known methods. Specifically, methods of the disclosure can be used in high-throughput applications and/or without having to dilute ADC samples during the assessment.