Dual-Transition Hydrogel Prevents Syringe Clogging
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Solution Overview
Problem
Conventional temperature-sensitive hydrogels used in drug delivery systems tend to clog syringe needles due to gelation upon reaching body temperature, and their pH sensitivity is insufficient for effective drug delivery, limiting their application in vivo.
Innovation Solution
A dual-transition polymeric hydrogel is developed, comprising a hydrophilic polyethylene glycol-based compound and a biodegradable polymer, combined with a pH-sensitive poly(β-aminoester urethane)-g-sulfonamide oligomer, which exhibits reversible sol-gel transition behavior responsive to both temperature and pH, preventing needle clogging and enabling stable drug delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional temperature-sensitive hydrogels are used for drug delivery, then sol-gel transition occurs at body temperature, but syringe needle clogging happens during injection
Solution Approach 1:
The patent introduces pH sensitivity as an additional parameter to control gelation, allowing the hydrogel to remain soluble at injection pH (acidic conditions) and only gel at physiological pH (7.4), thereby preventing needle clogging while maintaining reliable drug delivery
Solution Approach 2:
The patent creates a composite block copolymer combining temperature-sensitive blocks (for sol-gel transition) with pH-sensitive blocks containing sulfonamide groups (for pH-dependent solubility), achieving dual-responsive behavior that resolves the contradiction between reliable gelation and easy injection
2Reliability
If conventional pH-sensitive polymers are used, then some pH sensitivity is provided, but the sensitivity is insufficient for effective drug delivery in vivo
Solution Approach 1:
The patent enhances pH sensitivity by incorporating sulfonamide groups with specific pKa values that allow the polymer to respond sharply to physiological pH changes, enabling effective drug delivery by controlling gelation and drug release at target sites
Solution Approach 2:
The patent introduces distinct pH-sensitive blocks with sulfonamide groups at specific positions in the copolymer structure, creating localized regions of high pH sensitivity that enhance overall drug delivery effectiveness without compromising other functional blocks
3Reliability
If block copolymers with hydrophobic and hydrophilic blocks are used, then sol-gel transition is achieved, but initial burst release occurs
Solution Approach 1:
The patent combines hydrophobic blocks (for structural integrity and sustained release) with pH-sensitive blocks containing sulfonamide groups (for stable gel formation and controlled release), creating a composite structure that prevents initial burst release while maintaining reliable sol-gel transition
Solution Approach 2:
The patent uses pH-dependent ionization of sulfonamide groups to modulate the hydrophilicity/hydrophobicity balance dynamically, allowing the gel to form stable networks that prevent burst release while maintaining controlled drug release kinetics
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 dual-transition hydrogel effectively prevents initial burst release and ensures sustained drug delivery by forming stable gels at physiological conditions, capable of carrying both cationic and anionic drugs, proteins, and DNA, thus overcoming the limitations of conventional pH-sensitive block copolymers.
Implementation Method 1
exhibits reversible sol-gel transition behavior responsive to both temperature and pH
Implementation Method 2
sol-gel transition of a hydrogel made of an amphoteric polymer with both hydrophobic and hydrophilic groups
Implementation Method 3
the block compound exhibits a cationic/anionic dual transition behavior with pH change
Implementation Method 4
a pH-sensitive polymer comprising a sulfonamide group
Implementation Method 5
biodegradable polymer
Implementation Method 6
a copolymer consisting of a hydrophilic polymer, e.g., polyethylene glycol, and a biodegradable polyester
Data Source
AI summary
Disclosed is a dual-transition polymeric hydrogel. Also, provided is the use of the dual-transition polymeric hydrogel as a carrier for drug delivery and disease diagnosis, or in the preparation of a polymeric hydrogel-type pharmaceutical composition comprising the physiologically active agent loadable into the block copolymer. Being sensitive to pH as well as temperature, the block copolymer can form a more stable hydrogel at suitable temperatures and pH values. In addition, the block copolymer exhibits a dual transition behavior with pH values so that it can carry ionic drugs, proteins, DNA, and markers, whether positively or negatively charged, simultaneously. Therefore, it can be applied to a sustained drug delivery system for sparingly soluble, hydrophobic drugs, and hydrophilic drugs. Further, it is safe to and stable within the body, and is expected to find various applications in the medical field.