pH-Sensitive Polymer Conjugates for Sustained Drug Release
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Solution Overview
Problem
Current drug-polymer conjugates face challenges in achieving high biologically active molecule loading and controlled release profiles due to steric and thermodynamic issues during covalent attachment, leading to uneven drug distribution and potential burst release, which complicates treatment protocols, especially in combination therapies.
Innovation Solution
Development of a polymer particle with a specific repeat unit structure that allows for covalent binding of biologically active molecules, enabling controlled release through tailored bond types and environments, such as acidic cellular compartments, and enabling high loading capacities and sustained release profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If covalent attachment of biologically active molecules to preformed polymer backbones is attempted, then drug-polymer conjugates can be formed, but steric and thermodynamic problems prevent high biologically active molecule loading and uniform distribution
Solution Approach 1:
The patent changes the chemical parameters of the attachment bond by using different types of bonds (amide, ester, carbamate, carbonate, urea, thiocarbonate, thiourea, oxime, hydrazone, thiohydrazone, thioketone, ketal, acetal, orthoester) with different stabilities and formation conditions. This allows optimization of both loading capacity and attachment ease by selecting bonds suited to specific biologically active molecules and delivery requirements
Solution Approach 2:
The patent creates composite drug-polymer conjugates where biologically active molecules are covalently integrated with polymer backbones through chemically diverse linkages. The composite structure combines the polymer's structural properties with the drug's therapeutic properties, achieving high loading capacities while maintaining controlled release through the engineered bond diversity
2Device complexity
If all biologically active molecules are attached by the same type of bond, then conjugate formation is simplified, but burst release occurs when conditions hydrolyse that bond type, leading to uncontrolled release profiles
Solution Approach 1:
The patent segments the attachment bonds into multiple types with different hydrolytic stabilities (e.g., stable amide bonds versus labile ester or acetal bonds). This segmentation allows the conjugate to release drugs in a controlled, sustained manner rather than all at once, improving reliability of release rate control while maintaining manageable structural complexity through systematic bond selection
Solution Approach 2:
The patent introduces dynamic behavior to the conjugate system by incorporating bonds with varying stabilities that respond differently to physiological conditions. This creates a dynamic release profile where drugs are released at different rates based on their attachment bond type, enabling sustained release and improving therapeutic reliability without requiring overly complex conjugate structures
3Ease of manufacture
If conventional drug-polymer mixtures are used, then formulation is simple, but drug release occurs only when polymer dissolves or degrades, limiting release rate control
Solution Approach 1:
The patent applies preliminary action by pre-attaching biologically active molecules to the polymer backbone through covalent bonds before administration. This pre-established covalent linkage enables controlled release through targeted bond hydrolysis or cleavage, providing precise release rate control while maintaining formulation simplicity through direct conjugation methods
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 polymer particles achieve controlled and sustained release of biologically active molecules, improving treatment efficacy and patient compliance by reducing dose frequency and promoting synergistic effects in combination therapies.
Implementation Method 1
The drug is only released from the dosage form when the polymer is dissolved or degraded
Implementation Method 2
the biologically active molecule is covalently bound to the repeat unit
Data Source
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AI summary
There is provided a polymer comprising: (i) a repeat unit derived from a compound of formula (I) (Formula (I)) wherein, R1 and R2 are each independently selected from OH, OR', SH, SR', NH2, NHR' and NR'2; R' is C1-20 hydrocarbyl; each n is independently 0 or an integer between 1 and 6; each m is independently 0 or an integer between 1 and 4, and preferably at least one m is 1; and q is an integer between 1 and 8; and; (ii) a biologically active molecule, wherein said biologically active molecule is covalently bonded to said repeat unit; as well as methods for preparing such polymers, particles comprising said polymers and uses of said polymers and particles including use in the treatment of disease.