Centrosymmetric Eight-Arm PEG Derivative for Drug Loading
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Solution Overview
Problem
Current eight-arm polyethylene glycol derivatives lack precise control over molecular weight and distribution, leading to heterogeneity and reduced drug efficacy due to asymmetry in octavalent central groups, which affects the reactivity and stability of PEG chains, and do not allow for controlled degradation of pegylated drugs.
Innovation Solution
A centrosymmetric or approximately centrosymmetric eight-arm polyethylene glycol derivative with degradable moieties is introduced, featuring an octavalent central group and terminal functional groups, enabling precise control over molecular weight and distribution, enhanced drug loading, and environmentally responsive drug release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional asymmetric octavalent central groups are used in eight-arm polyethylene glycol derivatives, then drug loading capacity is improved, but molecular weight homogeneity deteriorates due to asymmetry affecting reactivity and stability
Solution Approach 1:
The patent applies asymmetry principle by designing a specific octavalent central group structure where four arms are connected through a tetravalent central group and four trivalent branching groups. This controlled asymmetric arrangement enables precise control over molecular weight and distribution while maintaining high drug loading capacity, resolving the contradiction between quantity and precision
2Stability of the object's composition
If non-degradable eight-arm polyethylene glycol derivatives are used, then structural stability is improved, but drug release control deteriorates due to inability to achieve environmentally responsive release
Solution Approach 1:
The patent applies dynamics principle by incorporating degradable moieties into the eight-arm polyethylene glycol structure, making the molecule dynamically responsive to environmental conditions. The degradable linkages allow the structure to remain stable under normal conditions but break down in response to specific environmental triggers, enabling controlled drug release while maintaining structural stability
3Quantity of substance
If linear polyethylene glycol is used for drug modification, then solubility is improved, but drug activity deteriorates due to embedding of drug molecules by PEG chains
Solution Approach 1:
The patent applies segmentation principle by using eight-arm branched polyethylene glycol structure instead of linear PEG. The branched architecture segments the PEG chains into eight separate arms radiating from a central group, preventing the chains from embedding and encapsulating drug molecules. This maintains high solubility while preserving drug activity through improved molecular accessibility
Data Source
AI summary
Disclosed are an 8-arm polyethylene glycol (PEG) derivative (formula 1), manufacturing method and modified bio-related substance thereby, wherein a tetravalent group U and four trivalent groups Ec form a highly symmetric octavalent central structure CORE0 together, Lc connects the octavalent center to eight PEG arms having polydiversity or monodiversity and having n1-n8 as the degrees of polymerization thereof. The terminal of one PEG chain is connected to at least one functional group F (k≥1), and said PEG chain and F can be directly connected (g=0) or connected with a divalent linking group L0 connected with a terminal branched group G (g=1) therebetween. The latter provides more reacting sites to combine more pharmaceutical molecules, thereby increasing the drug loading capacity. The near-center symmetric structure of the derivative allows more precise control over the molecular weight during large-scale production, thereby facilitating acquisition of a product having a narrower molecular weight distribution. A bio-related substance modified thereby has a more uniform and controllable performance.