Drug-Polymer Conjugates via Ring-Opening Polymerization
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Solution Overview
Problem
Current polymeric nanoparticle drug delivery systems face challenges in achieving high drug loading and encapsulation efficiency, leading to batch-to-batch variability and significant burst release of therapeutic molecules, which affects their efficacy and safety in clinical applications, particularly in cancer therapy.
Innovation Solution
A one-step method for preparing drug-polymer or drug-oligomer conjugates through ring-opening polymerization, where the drug acts as an initiator, resulting in nanoparticles with 100% encapsulation efficiency and predetermined drug loading, known as nanoconjugates, which are used to form particles with controlled release profiles and reduced particle heterogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional polymeric nanoparticle methods are used to encapsulate drugs, then drug loading can be increased, but encapsulation efficiency decreases and batch-to-batch variability increases
Solution Approach 1:
The drug is covalently attached to the polymer chain before nanoparticle formation through ring-opening polymerization, ensuring 100% encapsulation efficiency from the outset. This preliminary conjugation prevents any drug from being lost during the encapsulation process, as the drug becomes an integral part of the polymer structure rather than a separate component that might remain outside the nanoparticle.
Solution Approach 2:
The invention creates nanoparticles with heterogeneous drug distribution at the molecular level through controlled ring-opening polymerization. The drug is incorporated at specific locations along the polymer chain, creating local drug-rich regions that maintain high overall drug loading while ensuring uniform drug distribution across all nanoparticles, thereby eliminating batch-to-batch variability.
2Quantity of substance
If high drug loading is achieved in polymeric nanoparticles, then manufacturing cost decreases, but burst release increases leading to toxicity
Solution Approach 1:
The controlled ring-opening polymerization creates nanoparticles where drug molecules are distributed at specific locations along the polymer chains rather than being randomly aggregated. This local control prevents the formation of large drug aggregates on the nanoparticle surface that would otherwise cause burst release, while still maintaining high overall drug loading.
Solution Approach 2:
By covalently conjugating the drug to the polymer chain before nanoparticle formation, the invention ensures that all drug molecules are pre-positioned within the nanoparticle structure. This preliminary integration prevents any drug from being exposed on the surface where it could rapidly diffuse out, thereby eliminating burst release while maintaining high drug loading.
3Ease of operation
If drug molecules are encapsulated in polymeric nanoparticles without covalent bonding, then drug release can occur, but unwanted leakage during circulation increases
Solution Approach 1:
The drug is covalently conjugated to the polymer chain through ring-opening polymerization before nanoparticle formation, creating a stable drug-polymer conjugate. This preliminary covalent bonding ensures that the drug remains firmly attached during circulation, preventing unwanted leakage, while the conjugate structure allows for controlled release at the target site through polymer degradation or enzymatic cleavage.
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 method enables the production of nanoparticles with consistent drug loading and encapsulation efficiency, minimizing burst release and improving therapeutic efficacy by ensuring controlled and sustained drug delivery, thus enhancing the potential for clinical translation and regulatory approval.
Implementation Method 1
A method of making particulate drug delivery systems or vehicles employing the drug-polymer or drug-oligomer conjugates... The chemical species having at least one functional group which under the conditions of the reaction functions as an initiator of ring-opening polymerization
Data Source
AI summary
Methods for efficient preparation of drug-polymer (or oligomer) conjugates useful in the preparation of particles, including microparticles and nanoparticles, for delivery of the drug in vivo for therapeutic applications are provided. The invention also provides nanoparticles prepared by nanoprecipitation using drug-polymer/oligomer conjugates of the invention. The drug conjugates are formed during polymerization of the polymer or oligomer in which the drug is employed as an initiator of the polymerization of the monomers which form the polymer and/or oligomer. More specifically, the drug conjugates are formed by ring-opening polymerization of cyclic monomers in the presence of an appropriate ring-opening polymerization catalyst and the initiator (the drug). The method is particularly useful for formation of polymer/oligomer conjugates with drugs and other chemical species containing one or more hydroxyl groups or thiol groups.