Peptide-Linked Monodisperse PEG for Stable Antibody-Drug Conjugates
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Solution Overview
Problem
Existing antibody-drug conjugates (ADCs) face issues with hydrophobic drug aggregation and antibody stability due to hydrophobic drugs, and monodisperse polyethylene glycol side chains in branched linkers do not effectively mask hydrophobicity or prevent antibody degradation by intracellular enzymes.
Innovation Solution
A heterobifunctional monodisperse polyethylene glycol with two closely-bonded monodisperse polyethylene glycol side chains and a peptide linker that is degraded by intracellular enzymes, used to link antibodies and drugs, ensuring stable bonding and sustained drug release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional methods (NHS-ester or anhydride) are used to introduce carboxyl groups into PEG, then carboxyl groups can be introduced, but the molecular weight distribution broadens and monodispersity is lost
Solution Approach 1:
The patent changes the chemical parameters of the reaction system by using a novel cyanate ester method instead of conventional NHS-ester or anhydride methods. This parameter change enables carboxyl group introduction while preserving the narrow molecular weight distribution (PDI < 1.05) of the PEG polymer.
Solution Approach 2:
The patent introduces a cyanate ester as an intermediary reagent that reacts with terminal hydroxyl groups to form carbamate intermediates, which are then hydrolyzed to carboxyl groups. This intermediary approach avoids the side reactions that cause polydispersity in conventional methods.
2Adaptability or versatility
If PEG is used as a spacer arm in antibody-drug conjugates, then flexibility and reduced immunogenicity are achieved, but site-specific conjugation and controlled drug-to-antibody ratio are difficult
Solution Approach 1:
The patent modifies only the terminal regions of the PEG chain by introducing carboxyl groups at the ends, while maintaining the flexible ether backbone properties. This localized modification enables site-specific conjugation through controlled coupling of drug molecules to the terminal carboxyl groups, preserving the bulk flexibility benefits of PEG.
Solution Approach 2:
The patent segments the PEG structure by distinguishing between the unmodified flexible ether backbone and the modified terminal carboxyl regions. This segmentation allows the backbone to provide flexibility while the terminal carboxyl groups provide controlled, site-specific conjugation points for drug attachment.
3Adaptability or versatility
If multiple carboxyl groups are introduced into PEG to increase functionality, then versatility improves, but control over number and position of carboxyl groups becomes difficult
Solution Approach 1:
The patent performs preliminary action by introducing a specific number of carboxyl groups at defined positions during the PEG synthesis stage, rather than attempting to modify PEG afterward. The cyanate ester method allows controlled introduction of exactly one carboxyl group per terminal hydroxyl, enabling precise control over the number and position of functional groups before conjugation.
Data Source
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AI summary
A heterobifunctional monodisperse polyethylene glycol with two adjacent monodisperse polyethylene glycol side chains, in which a peptide linker is degraded by intracellular enzymes to release a drug slowly and effectively mask the hydrophobicity of the drug, and an antibody-drug conjugate in which the antibody and the drug are bound using same is provided. A heterobifunctional monodisperse polyethylene glycol represented by the formula (1): wherein each symbol in the formula (1) is as defined in the DESCRIPTION.