Heterobifunctional Monodispersed PEG Linker for ADC Homogeneity
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Solution Overview
Problem
Current antibody-drug conjugates (ADCs) face challenges with hydrophobic drug stability and homogeneity due to the use of branched polyethylene glycol linkers, leading to aggregation and reduced therapeutic efficacy, and existing heterobifunctional compounds with chiral centers risk stereoisomer formation and steric inversion during chemical conversion processes.
Innovation Solution
A heterobifunctional monodispersed polyethylene glycol compound with two adjacent side chains bonded to a quaternary carbon atom via a stable ether bond, eliminating chiral centers and minimizing steric hindrance, which is used to link antibodies and drugs, maintaining hydrophilicity and preventing decomposition into single-chain polyethylene glycol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If monodispersed polyethylene glycol is used as a linker main chain to guarantee uniformity and simplify purification, then homogeneity and ease of manufacture are improved, but the ability to mask hydrophobicity and prevent aggregation is insufficient
Solution Approach 1:
The patent divides the linker into two functional parts: a monodispersed polyethylene glycol portion for ensuring homogeneity and simplifying purification, and a branched linker portion for effectively masking hydrophobicity and preventing aggregation. This segmentation allows each part to fulfill its specific function optimally.
Solution Approach 2:
The patent creates a composite linker structure combining monodispersed polyethylene glycol with a branched linker system. This composite approach integrates the advantages of both structures: the uniformity and ease of manufacture from monodispersed PEG and the hydrophobicity-masking capability from the branched structure.
2Ease of manufacture
If existing heterobifunctional compounds with chiral centers are used for linking, then chemical reactivity is achieved, but stereoisomer formation and steric inversion occur during chemical conversion
Solution Approach 1:
The patent removes the problematic chiral centers from the linker structure by using a quaternary carbon atom instead. This extraction of the harmful element (chirality) eliminates the source of stereoisomer formation and steric inversion while preserving the necessary chemical reactivity through heterobifunctional groups.
Solution Approach 2:
The patent changes the structural parameter of the linker from a chiral center to a quaternary carbon atom. This parameter change fundamentally alters the stereochemical behavior, preventing stereoisomer formation and steric inversion during chemical conversion processes while maintaining manufacturing feasibility.
3Object-affected harmful factors
If branched polyethylene glycol is used to mask hydrophobicity, then aggregation is reduced, but decomposition into single-chain polyethylene glycol occurs
Solution Approach 1:
The patent provides prior protection against decomposition by using a quaternary carbon atom to bond the polyethylene glycol chains. This structural arrangement creates stable ether bonds that prevent hydrolysis and decomposition into single-chain PEG, while the branched configuration maintains the ability to mask hydrophobicity.
4Productivity
If multiple drugs are bonded to antibody to increase therapeutic effect, then medical efficacy is improved, but aggregation and stability decrease due to hydrophobicity
Solution Approach 1:
The patent introduces a composite linker system as an intermediary between the hydrophobic drug and the antibody. The branched portion of the linker masks the hydrophobicity of multiple drugs, preventing aggregation and maintaining stability, while the monodispersed PEG portion ensures uniformity. This intermediary structure enables multiple drugs to be bonded to the antibody without compromising reliability.
Data Source
AI summary
A heterobifunctional monodispersed polyethylene glycol represented by the formula (1):wherein X1 and Y1 are each an atomic group containing a functional group capable of forming a covalent bond upon a reaction with a functional group present in a biofunctional molecule, the functional group contained in the atomic group X1 and the functional group contained in the atomic group Y1 are different from each other; R1 is a hydrocarbon group having from 1 to 7 carbon atoms or a hydrogen atom; n is an integer of 3 to 72; 1 is an integer of 2 to 72; and A1, B1 and C1 are as defined herein.