Imide Branching Point Polymer for Conjugation
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Solution Overview
Problem
Conjugation of polymers with active agents, particularly polypeptides, often results in inactive forms due to large poly(ethylene glycol) moieties blocking access to ligands, and existing branched polymer derivatives are complex to synthesize and purify, making them inconvenient for use in conjugation reactions.
Innovation Solution
A polymer structure comprising a first and second water-soluble polymer segment covalently linked through an imide moiety, which serves as a branching point, allowing for direct or indirect attachment of reactive groups, facilitating easier synthesis and purification, and potentially reducing inactivity by controlling polymer access to ligands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If large poly(ethylene glycol) moieties are used to increase water solubility, then water solubility is improved, but the polymer blocks access to ligands and renders the conjugate inactive
Solution Approach 1:
The polymer is divided into multiple smaller segments (e.g., multiple PEG chains) attached to a central core structure, replacing a single large PEG moiety. This segmentation maintains the overall water solubility enhancement while reducing the steric bulk that blocks ligand access, thereby preserving biological activity of the conjugate.
Solution Approach 2:
The invention transitions from linear polymer architecture to a branched or dendritic structure, adding dimensional complexity. This spatial reorganization allows the polymer to occupy three-dimensional space more efficiently, providing solubility benefits without creating a linear barrier that blocks ligand binding sites.
2Reliability
If branched polymer derivatives are used to reduce inactivity, then biological activity is improved, but synthesis and purification become complex
Solution Approach 1:
The branched polymer is synthesized through modular assembly of repeating unit segments, each containing a standardized set of functional groups. This segmentation allows for stepwise synthesis using similar reaction conditions for each unit, simplifying the overall manufacturing process despite the branched architecture.
Solution Approach 2:
The invention employs systematic variation of key parameters such as the number of branches, length of PEG chains, and core structure properties to optimize both biological activity and manufacturability. By controlling these parameters, the polymer achieves desired activity while maintaining feasible synthesis and purification protocols.
Data Source
AI summary
The invention provides a water-soluble polymer comprising (i) an imide group comprising a linking nitrogen atom, a first carbonyl group covalently attached to the linking nitrogen atom, and a second carbonyl group covalently attached to the linking nitrogen atom; (ii) a first water-soluble polymer segment covalently attached, either directly or through one or more atoms, to the first carbonyl group of the imide group and (iii) a second water-soluble polymer segment covalently attached, either directly or through one or more atoms, to the second carbonyl group of the imide group. The invention also provides, among other things, methods for preparing polymers, conjugates, pharmaceutical compositions and the like.