Polypeptide Block Copolymer Micelles for pH-Targeted Drug Delivery
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Solution Overview
Problem
Current drug delivery systems face challenges in targeting specific areas within the body, such as cancer cells, due to lack of pH sensitivity and control over degradation rates, leading to inefficient drug release and potential toxicity from residual degradation products.
Innovation Solution
A polypeptide-based block copolymer with pH sensitivity and biodegradability via peptidase, formed from a polyglutamic acid-based compound and a hydrophilic polyethylene glycol-based compound, which self-assembles into micelles that collapse and degrade at specific pH ranges, allowing controlled drug release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If polyethylene glycol and biodegradable polymer are used to form micelles, then biodegradability is achieved, but pH sensitivity and target-oriented drug release are lost
Solution Approach 1:
The patent combines polyethylene glycol (providing biodegradability) with polyglutamic acid-based compounds containing tertiary amine groups (providing pH sensitivity). This composite block copolymer structure integrates both functionalities: the PEG component ensures biodegradability while the polyglutamic acid component with tertiary amine groups provides pH-responsive micelle formation and collapse, enabling target-oriented drug release to cancer cells
2Adaptability or versatility
If poly(β-aminoester) and polyethylene glycol are used to form micelles, then pH sensitivity is achieved, but control over degradation rate is lost
Solution Approach 1:
The patent changes the chemical structure of the polyglutamic acid-based compound by introducing tertiary amine groups, which fundamentally alters the degradation mechanism from uncontrolled hydrolysis to enzyme-mediated degradation by peptidases. This parameter change in the chemical structure enables both pH sensitivity (through tertiary amine protonation) and controlled degradation rate (through peptidase activity), resolving the contradiction
3Productivity
If conventional micelles are used for drug delivery, then drug delivery is achieved, but biotoxicity from degradation products occurs
Solution Approach 1:
The patent converts the potential harm of degradation products into a benefit by designing the block copolymer to degrade into harmless amino acids and peptides through peptidase action. The polyglutamic acid-based compound with tertiary amine groups degrades into biocompatible products, eliminating biotoxicity while maintaining effective drug delivery capability
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 polypeptide-based block copolymer enables targeted drug delivery by forming and collapsing micelles in response to pH changes, reducing toxicity and allowing complete elimination of degradation products, thus enhancing the efficacy and safety of drug delivery systems.
Implementation Method 1
a thermostable and uniform spherical structure formed by low-molecular weight materials having amphiphilicity
Implementation Method 2
having a hydrophilic group and a hydrophobic group at the same time
Implementation Method 3
biodegradability due to peptidase
Implementation Method 4
micelles are collapsed and thereby drugs can be released when pH is 7.0 or less, and micelles are formed and collapsed by the pH difference of 0.2
Data Source
AI summary
The present disclosure relates to a polypeptide based block copolymer having biodegradability due to peptidase, and a process for the preparation thereof, and polymer micelles using the same. The block copolymer according to the present disclosure is a block copolymer of a polyethylene glycol-based compound having properties such that the solubility for water is different depending on the pH, but cannot form micelles due to a self-assembly phenomenon; and a polyglutamic acid-based compound formed using an aminolysis reaction of glutamic acid and tertiary amine in which the end of one alkyl group is substituted with NH2, or using an aminolysis reaction of glutamic acid and triamine. The block copolymer of the present disclosure has advantages in that the block polymer has both pH sensitivity and biodegradability due to peptidase in the body, and thereby a degradation rate related to a drug release cycle is controlled. Therefore, the block copolymer according to the present disclosure is effective in that the block copolymer can be used as a target-oriented drug delivery agent depending on the pH changes in the body, and as a drug delivery agent that can control the rate of degradation.