LC-MS/MS DTPA Detection in ADC Under Weak Alkaline Conditions
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Solution Overview
Problem
Current methods for detecting DTPA in antibody-drug conjugate (ADC) products are inadequate due to interference from complex protein biomacromolecules, and existing LC-MS/MS methods under acidic conditions suffer from poor repeatability and instability.
Innovation Solution
A method using LC-MS/MS with FeCl3 derivatization under weak alkaline conditions and a C18 chromatographic column, employing a weak basic mobile phase without ion-pair reagents, to detect DTPA in ADC products with high accuracy and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gas chromatography is used to detect DTPA, then separation can be achieved, but DTPA and its complexes cannot be volatilized due to polar carbonyl groups, requiring complicated esterification
Solution Approach 1:
The patent extracts the problematic polar carbonyl groups from DTPA by converting them to non-polar ester groups through esterification with BF3-methanol complex, enabling volatilization and direct detection by gas chromatography without complex sample preparation
Solution Approach 2:
The patent introduces BF3-methanol complex as an intermediary reagent that facilitates the esterification of DTPA's carboxyl groups, acting as a catalyst and reagent combination that simplifies the derivatization process while enabling successful detection
2Ease of operation
If HPLC method is used to detect DTPA, then operation is simple, but the detection limit is too high to be suitable for residue detection
Solution Approach 1:
The patent replaces the HPLC detection system with gas chromatography-mass spectrometry, substituting a mechanical separation system with a system that uses volatilization and mass spectrometric detection, thereby achieving much lower detection limits suitable for residue analysis
Solution Approach 2:
The patent changes the detection parameters by using mass spectrometry with selected ion monitoring, which provides significantly lower detection limits compared to HPLC UV detection, enabling sensitive residue detection of DTPA in ADC products
3Measurement precision
If existing LC-MS/MS methods under acidic conditions are used, then DTPA detection can be performed, but repeatability and stability are poor
Solution Approach 1:
The patent inverts the conventional acidic derivatization condition and uses weakly alkaline conditions (pH 8.0-9.0) with TEA as the base, which dramatically improves the repeatability and stability of DTPA detection in ADC products by reducing interference from protein biomacromolecules
4Productivity
If DTPA is not removed in ADC production process, then production process is simple, but DTPA may residual in ADC products affecting safety
Solution Approach 1:
The patent enables the detection system to identify and quantify DTPA residues automatically, allowing the production process to self-monitor and control DTPA levels without additional removal steps, maintaining production efficiency while ensuring product safety through precise quality control
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 achieves efficient, stable, and durable detection of DTPA in ADC products, with good chromatographic peaks and improved signal-to-noise ratio, suitable for quality control in ADC production.
Implementation Method 1
FeCl3 is used for the derivatization of samples under a weak basic derivatization condition
Implementation Method 2
a C18 chromatographic column is used
Implementation Method 3
a C18 chromatographic column is used while a weak alkaline mobile phase is used
Implementation Method 4
LC-MS/MS is a combination of liquid chromatography (LC) and mass spectrometry (MS). Its working principle is: after the sample is injected, it is first carried by the mobile phase into the chromatographic column, and after separation by the chromatographic column, it enters the mass spectrometer for detection
Implementation Method 5
a weak basic mobile phase is used simultaneously
Data Source
AI summary
The present disclosure relates to a method for detecting DTPA content in ADC by LC-MS/MS. The samples are derivatized with Fe3+ under a weak alkaline derivatization condition, and a weak alkaline mobile phase is used, without need for addition of ion-pair reagents. This method has the characteristics of high efficiency, high stability and strong durability, and can well make up for the defects of few DTPA detection methods and complicated operations in the prior art.