Biodegradable Polyesteramide Copolymers for Sustained Drug Delivery
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Solution Overview
Problem
In medical applications, particularly in ophthalmology, there is a need for biodegradable fibers that can deliver bioactive agents with a sustained release over time, as enzymatically degradable polyesteramides fail to degrade adequately in the vitreous region of the eye due to low enzyme presence, leading to compromised degradability and drug delivery.
Innovation Solution
Development of biodegradable poly(esteramide) copolymers that degrade hydrolytically via a bulk erosion mechanism, incorporating L-Lysine and L-lysine-benzyl, which provides a sustained release of bioactive agents without enzymatic degradation, addressing the limitations of existing polyesteramides that degrade via surface erosion and potentially cause pH drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If enzymatically degradable polyesteramides are used for drug delivery, then the polymers can be broken down by enzymes to release bioactive agents, but they fail to degrade adequately in the vitreous region of the eye due to low enzyme presence
Solution Approach 1:
The patent changes the degradation mechanism parameter from enzymatic to hydrolytic degradation. The polyesteramide copolymers are specifically designed with chemical bonds that break down through hydrolysis rather than enzymatic action, enabling them to function reliably in the enzyme-poor vitreous environment while maintaining controlled degradation rates
Solution Approach 2:
The patent creates composite polyesteramide copolymers combining different monomer units (amino acid-derived diols and dicarboxylic acids) to achieve both hydrolytic degradability and sustained drug release properties. The copolymer structure integrates multiple functional components that work together to provide environmental adaptability
2Reliability
If polyesteramides degrade via surface erosion, then the degradation occurs at the polymer surface, but this causes pH drops that may trigger inflammatory responses
Solution Approach 1:
The patent changes the degradation mode parameter from surface erosion to bulk erosion. The copolymer structure is designed to undergo hydrolytic degradation throughout the bulk material rather than at the surface, which prevents localized pH drops and associated inflammatory responses while maintaining controlled drug release
Solution Approach 2:
The patent converts the potential harmful effect of rapid surface degradation (pH drops) into a beneficial bulk erosion mechanism. By designing the copolymer to degrade uniformly throughout its structure, the harmful localized pH changes are eliminated while the degradation process itself remains controlled and sustained
3Duration of action of moving object
If fibers are designed for sustained release of bioactive agents, then the release duration is extended, but the degradation mechanism must be reliable in enzyme-poor environments like the vitreous
Solution Approach 1:
The patent changes the fundamental degradation parameter from enzymatic to hydrolytic, enabling the fibers to achieve both sustained release duration and reliability in the vitreous environment. The hydrolytic mechanism operates independently of enzyme presence while maintaining controlled degradation kinetics
Solution Approach 2:
The patent uses composite polyesteramide copolymers that integrate multiple monomer units with different degradation rates and drug affinity characteristics. This composite structure enables simultaneous achievement of sustained release over time and reliable degradation in enzyme-poor environments through hydrolysis
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 hydrolytically degradable fibers maintain a stable pH and ensure continuous bioactive agent delivery, overcoming the limitations of enzymatically degradable polymers by providing a controlled and sustained release mechanism suitable for ophthalmic applications.
Implementation Method 1
biodegradable poly(esteramide) copolymers which degrade hydrolytically via a bulk erosion mechanism
Data Source
AI summary
The present inventioN relates to fibers comprising a polyesteramide (PEA) having a chemical formula described by structural formula (IV), wherein −m+p varies from 0.9-0.1 and q varies from 0.1 to 0.9, −m+p+q=1 whereby m or p could be 0, −n is about 5 to about 300; (pref. 50-200), —R1 is independently selected from the group consisting of (C2-C20) alkylene or (C2-C20) alkenylene and combinations thereof; —R3 and R4 in a single backbone unit m or p, respectively, are independently selected from the group consisting of hydrogen, (C1-C6)alkyl, (C2-C6)alkenyl, (C2-C6)alkynyl, (C6-C10)aryl, —(CH2)SH, —(CH2)2S(CH3), —CH2OH, —CH(OH)CH3, —(CH2)4NH3+, —(CH2)3NHC(═NH2+)NH2, —CH2COOH, —(CH2)COOH, —CH2—CO—NH2, —CH2CH2—CO—NH2, —CH2CH2COOH, CH3—CH2—CH(CH3)—, (CH3)2—CH—CH2—, H2N—(CH2)4—, Ph-CH2—, CH═C—CH2—, HO-p-Ph-CH2—, (CH3)2—CH—, Ph-NH—, NH—(CH2)3—C—, NH—CH═N—CH═C—CH2—. —R5 is selected from the group consisting of (C2-C20)alkylene, (C2-C20)alkenylene, alkyloxy or oligoethyleneglycol, —R6 is selected from bicyclic-fragments of 1,4:3,6-dianhydrohexitols of structural formula (III); —R7 is selected from the group consisting of (C6-C10)aryl (C1C6)alkyl, —R8 is —(CH2)4-; whereby a is at least 0.05 and b is at least 0.05 and a+b=1.