Spectrophotometric Quantitation of Polysorbate in Protein Samples
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Solution Overview
Problem
Current methods for determining the concentration of polysorbate in protein samples and drug-to-antibody ratios in antibody-drug conjugates are cumbersome, prone to errors, and require complex sample preparation due to overlapping absorbance spectra and binding issues, lacking direct and efficient measurement techniques.
Innovation Solution
The method employs spectrophotometric techniques to factor out overlapping signals by using the ratio of slopes from absorbance versus path length plots at different wavelengths, allowing for the direct measurement of polysorbate concentration in protein samples and drug-to-antibody ratios in ADCs without purification or dilution, using variable path-length spectrophotometry and slope spectroscopy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional spectrophotometric methods are used to measure polysorbate concentration, then measurement can be performed, but overlapping absorbance spectra cause measurement precision to deteriorate
Solution Approach 1:
The patent segments the overlapping absorbance spectrum into multiple discrete wavelength measurements (at least two different wavelengths). By measuring absorbance at multiple wavelengths and solving the system of equations, the method isolates the polysorbate contribution from other components in the mixture, thereby resolving the measurement precision issue caused by spectral overlap.
Solution Approach 2:
The patent transitions from single-wavelength measurement to multi-wavelength measurement, adding a dimensional aspect to the measurement process. By incorporating wavelength as an additional measurement dimension and using mathematical resolution of overlapping spectra, the method achieves precise polysorbate quantification despite absorbance overlap.
2Measurement precision
If sample preparation steps (separation, filtration, dilution) are performed to improve measurement accuracy, then measurement precision improves, but time consumption and process complexity increase
Solution Approach 1:
The patent enables the measurement system to handle complex mixtures directly without requiring external sample preparation interventions. The multi-wavelength spectrophotometric method with mathematical resolution allows the instrument to self-compensate for interfering substances, eliminating the need for manual separation, filtration, or dilution steps.
Solution Approach 2:
The patent extracts the polysorbate concentration information from the complex mixture by using multi-wavelength measurements and mathematical resolution. Instead of physically separating polysorbate from other components, the method extracts the specific spectral contribution of polysorbate through computational analysis of absorbance data at multiple wavelengths.
3Reliability
If conventional methods are used to determine drug-to-antibody ratios, then measurement can be performed, but overlapping absorbance spectra and binding issues cause reliability to deteriorate
Solution Approach 1:
The patent segments the absorbance signal into distinct contributions from drug, antibody, and their conjugate by measuring at multiple wavelengths. The mathematical resolution process separates these overlapping signals, allowing reliable determination of drug-to-antibody ratios without interference from spectral overlap or binding-related measurement artifacts.
Solution Approach 2:
The patent uses more wavelength measurements than the minimum required, providing excess measurement data that enhances the reliability of the drug-to-antibody ratio determination. This excessive measurement approach allows for better statistical analysis and more robust resolution of overlapping spectra.
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 enables accurate and efficient quantitation of polysorbate concentrations and drug-to-antibody ratios in complex mixtures, reducing errors and time consumption, and can be applied to solutions with multiple overlapping wavelengths, providing a direct and simplified measurement method.
Implementation Method 1
collecting a set of optical density versus wavelength spectra at two or more path lengths of a buffer of a solution
Implementation Method 2
using the ratio of slopes from absorbance versus path length plots at different wavelengths, allowing for the direct measurement of polysorbate concentration
Data Source
AI summary
The present invention relates to methods of spectrophotometric determination of the presence of particular substances in a complex mixture of compounds. This invention relates to methods for determining the concentration of various components of complex biological samples including the determination of the concentration of polyoxyethylene containing compounds including polysorbate in protein containing samples as well as determining the ratio of drug to antibody ratios in antibody-drug conjugate solutions.