Siderophore Antibiotic Conjugates for β-Lactamase-Triggered Release
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Solution Overview
Problem
Current antibiotics face challenges in delivering drugs across the outer membrane of Gram-negative bacteria and efficiently releasing them inside the bacterial cytoplasm due to low permeability and enzymatic degradation, particularly by β-lactamases.
Innovation Solution
Development of novel antibiotic conjugates that utilize a siderophore moiety linked to a β-lactamase substrate, which is hydrolyzed by bacterial β-lactamases to release the drug moiety, such as oxazolidinone, inside the periplasm or cytoplasm of Gram-negative bacteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antibiotics are conjugated to siderophores for delivery to Gram-negative bacteria, then the ability to cross the outer membrane is improved, but the difficulty to cross the inner membrane and release the antibiotic into the cytoplasm worsens
Solution Approach 1:
The conjugate is divided into functional segments: a siderophore portion for outer membrane targeting, a linker portion for controlled release, and an antibiotic portion for cytoplasmic action. This segmentation allows each component to perform its specific function optimally - the siderophore facilitates outer membrane crossing while the linker enables subsequent intracellular release mechanisms
Solution Approach 2:
The linker acts as an intermediary between the siderophore and antibiotic portions. It mediates the transition from extracellular delivery to intracellular release, providing a controlled mechanism for antibiotic liberation within the bacterial cell through enzymatic cleavage by bacterial enzymes
2Reliability
If antibiotics are delivered via siderophore conjugates, then delivery to bacteria through iron transporters is improved, but the challenge to efficiently release the antibiotic from the siderophore worsens
Solution Approach 1:
The conjugate is pre-designed with a built-in release mechanism where the linker is positioned to be cleaved by bacterial enzymes after cellular uptake. This preliminary arrangement ensures that once inside the cell, the antibiotic is automatically released without requiring additional complex mechanisms
Solution Approach 2:
The design converts the bacterial defense mechanism (β-lactamases and other enzymes) into a beneficial release mechanism. These bacterial enzymes that would normally degrade free antibiotics are instead utilized to cleave the linker and trigger controlled antibiotic release from the conjugate
3Reliability
If conventional antibiotics are used against β-lactamase producing strains, then treatment of susceptible bacteria is effective, but drug resistance and enzymatic degradation worsen
Solution Approach 1:
The siderophore-conjugate structure serves as a protective intermediary that shields the antibiotic portion from premature degradation by extracellular β-lactamases. The antibiotic is delivered in a protected state to the bacterial cell, where it is then released in its active form inside the cell, bypassing extracellular enzymatic degradation
Solution Approach 2:
The conjugate structure provides preliminary protection against β-lactamase degradation before the antibiotic reaches its target. By concealing the antibiotic within the conjugate structure during extracellular transit, the design preemptively prevents enzymatic destruction that would otherwise occur
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 conjugates effectively transport antibiotics across the bacterial membrane and ensure release within the bacterial cell, enhancing their efficacy against β-lactamase-producing strains and other Gram-negative bacteria.
Implementation Method 1
drugs may be conjugated to a siderophore, which may then be delivered to the bacteria through the use of the iron transporters located on the outer membrane of the bacteria
Implementation Method 2
the β-lactamases substrate moiety is hydrolyzed by the native β-lactamases of the bacteria, allowing the release of the drug moiety
Data Source
AI summary
Provided are antibiotic conjugate compounds of formula (I) and pharmaceutical compositions thereof. Also provided are methods of treating treat bacterial infection, including infections caused by Gram-negative bacteria, by administering compounds of formula (I).