Alkyl Ether Bonded Liposomes for Targeted Drug Delivery
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Solution Overview
Problem
Current liposomes face challenges with rapid elimination in circulation and non-specific binding, leading to inefficient and non-selective delivery of therapeutic agents, despite advancements in coating with polymers like PEG and functionalization with guiding ligands.
Innovation Solution
Liposomes are functionalized with a sterol, such as cholesterol, using an alkyl ether bond to attach a polyethylene glycol (PEG) chain and a guiding peptide, which enhances stability and homogeneity, allowing for improved targeting and delivery of therapeutic agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liposomes are coated with PEG and functionalized with guiding ligands to improve delivery selectivity and half-life, then targeting efficiency and circulation time are improved, but the chemical stability and suspension stability of the liposome structure deteriorate due to the use of carbamate bonds
Solution Approach 1:
The patent changes the chemical bond type from carbamate to alkyl ether, fundamentally altering the chemical stability parameter of the liposome structure. This parameter change resolves the contradiction by providing both improved suspension stability and maintained delivery selectivity, as the ether bond is chemically more stable while preserving the functional properties of PEG and guiding ligands
Solution Approach 2:
The patent creates a composite structure where cholesterol is covalently bonded to PEG via an alkyl ether bond, and the PEG is further functionalized with guiding ligands. This composite material approach allows combining the stability of ether bonds with the functional benefits of PEG coating and targeted delivery ligands, simultaneously achieving both structural stability and delivery efficiency
2Ease of manufacture
If carbamate bonds are used to attach PEG and guiding ligands to liposomes, then the functionalization process is simplified, but the homogeneity of particle size distribution and suspension stability deteriorate
Solution Approach 1:
The patent changes the bond chemistry from carbamate to alkyl ether, which alters the physical properties of the liposome membrane. This parameter change results in more uniform membrane packing and homogeneous particle size distribution, while the functionalization process remains straightforward through standard conjugation chemistry
3Duration of action of stationary object
If rapid elimination in circulation is addressed by PEG coating, then plasma half-life is extended, but non-specific binding issues persist leading to incorrect delivery
Solution Approach 1:
The patent merges two functions into a single integrated structure: the PEG coating that extends half-life and the guiding ligand that ensures specific targeting. By covalently linking both to the cholesterol anchor through stable alkyl ether bonds, the system achieves simultaneous improvement in both circulation time and delivery accuracy, eliminating the trade-off between these two parameters
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 use of alkyl ether bonds in liposomes results in superior suspension stability, homogeneous particle size distribution, and enhanced delivery efficiency to target cells compared to carbamate bonds, improving the physico-chemical properties and therapeutic efficacy.
Implementation Method 1
The binding between the cholesterol molecule and the PEG is made by an alkyl ether group
Implementation Method 2
a guiding ligand, capable of selectively binding to one or several receptors present in a target cell
Data Source
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AI summary
The invention relates to conjugates in which a sterol is functionalized by an ether bond with a water-soluble polymer to which a guiding ligand is bound. These conjugates improve the physico-chemical and delivery properties of their carrying vesicles, making these more stable, homogeneous and effective. A method for their preparation, a pharmaceutical composition containing said liposomes, and their therapeutic use are described as well.