Reduction-Sensitive Polyesteramides for Targeted Drug Delivery
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Solution Overview
Problem
Current biodegradable polymers for intracellular drug delivery are unstable in extracellular fluids, leading to premature degradation and drug release before reaching the target site, resulting in higher dosages and potential side effects due to non-specific drug release.
Innovation Solution
Development of reduction-sensitive biodegradable polyesteramides (PEA-SS) with disulfide linkages in the backbone, using alpha-amino acids, diols, and aliphatic dicarboxylic acids, which are enzymatically degradable, maintaining stability in circulation and degrading rapidly within cellular compartments to prevent premature drug release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If biodegradable polymers are used for intracellular drug delivery, then they can degrade and release drugs, but they are unstable in extracellular fluids leading to premature degradation
Solution Approach 1:
The patent applies local quality by incorporating disulfide bonds specifically at the linkage points between polymer blocks, while the bulk polymer segments remain hydrolytically stable. This localized placement of reduction-sensitive groups allows the polymer to maintain stability in extracellular fluids while enabling controlled degradation in the reductive intracellular environment, thus resolving the contradiction between extracellular stability and intracellular degradability.
2Productivity
If higher dosages of drugs are used to compensate for premature release, then drug delivery efficacy may be maintained, but side effects increase due to non-specific drug release
Solution Approach 1:
The disulfide bonds act as an intermediary mechanism that mediates between the stable polymer structure and the drug release function. These bonds remain intact in extracellular fluids, preventing premature drug release and side effects, while being selectively cleaved by intracellular reducing agents to enable controlled drug release at the target site, thus maintaining efficacy without increasing dosage.
3Stability of the object's composition
If non-degradable building blocks are used in reduction sensitive polymers, then polymer stability can be achieved, but fragments may bio accumulate in tissues or organs
Solution Approach 1:
The patent applies parameter changes by selecting building blocks with specific degradation characteristics - using esters and amides that hydrolyze into naturally occurring, non-toxic, and readily metabolized products. This parameter selection ensures that when the polymer degrades intracellularly, the resulting fragments can be safely processed and eliminated by biological systems, avoiding bioaccumulation while maintaining sufficient stability during circulation.
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 PEA-SS polymers exhibit stability in extracellular fluids and controlled degradation within cells, allowing for targeted drug delivery with lower drug concentrations, minimizing side effects and ensuring the degradation products are readily metabolized by the body.
Implementation Method 1
reduction sensitive biodegradable polymers which comprise disulphide bonds as the reductive group
Implementation Method 2
which are enzymatically degradable, maintaining stability in circulation and degrading rapidly within cellular compartments
Data Source
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AI summary
The present invention relates to biodegradable polyesteramides (PEAs) comprising hydrophobic alpha -amino acids, diols, aliphatic dicarboxylic acids and optionally diamines whereby at least one of the dicarboxylic acids, diols or diamines comprises disulphide linkages. The present invention also relates to the use of the polyesteramides in medical applications such as cancer treatment, ophthalmic applications, therapeutic cardiovascular applications, veterinary applications, pain management applications, MSK applications and vaccine delivery compositions. The present invention also relates to a drug delivery composition comprising the PEA's and to a drug delivery system such as micro-or nanoparticles, micelles, liposomes, polymerosomes, micro- and nanogels, polymerosomes or nanotubes.