Thiolated Chitosan Ophthalmic Solution for Dry Eye Relief
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Solution Overview
Problem
Current treatments for dry eye syndrome are inadequate, with existing ocular lubricants requiring frequent application and often causing side effects like burning and stinging, leading to poor patient compliance and ineffective symptom relief.
Innovation Solution
A sterile aqueous ophthalmic solution containing N-(N-acetylcysteinyl-)chitosan with a specific content of free thiol groups is applied prior to sleep, providing prolonged tear film restoration and reduced ocular side effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional ocular lubricants are used, then tear film stability is improved, but application frequency must be increased
Solution Approach 1:
The patent modifies the chemical parameters of ocular lubricants by incorporating polymers with specific molecular weights, viscosities, and mucoadhesive properties. This changes the physical-chemical parameters of the tear film to extend its stability duration, reducing the need for frequent applications
Solution Approach 2:
The invention uses composite formulations combining multiple polymers (e.g., hyaluronic acid with cellulose derivatives) to create a synergistic effect that enhances both tear film stability and duration of action, allowing longer intervals between applications
2Duration of action of moving object
If high viscosity products are used to increase residence time, then ocular residence time is improved, but visual blurring increases
Solution Approach 1:
The patent creates localized viscosity enhancement at the ocular surface through mucoadhesive polymers that bind specifically to the conjunctival and corneal mucosa. This provides high residence time at the target site while maintaining lower overall formulation viscosity to minimize visual blurring
Solution Approach 2:
The invention uses mucoadhesive polymers as intermediary substances that bridge the lubricant formulation and the ocular surface mucosa. These polymers anchor the formulation locally, extending residence time without requiring high bulk viscosity that would cause blurring
3Duration of action of moving object
If thiolated chitosan is used to increase mucoadhesion, then ocular residence time is improved, but ocular side effects increase
Solution Approach 1:
The patent optimizes the thiolation degree of chitosan and adjusts formulation parameters such as pH, ionic strength, and polymer concentration to minimize side effects while maintaining enhanced mucoadhesion and residence time
Solution Approach 2:
The invention uses N-acetylcysteine as a model compound to establish the optimal thiol group configuration on chitosan, copying the successful mucoadhesive and protective properties of free thiols while maintaining polymer structure and minimizing irritation
4Reliability
If frequent instillation is required for symptom relief, then symptom management is improved, but patient compliance deteriorates
Solution Approach 1:
The patent creates formulations that provide continuous symptom relief through extended ocular residence time and sustained tear film stabilization. This reduces the number of required applications from multiple times daily to once or twice daily, significantly improving patient compliance while maintaining reliable symptom management
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 solution effectively alleviates dry eye symptoms for up to 24 hours with a single application, reducing the need for frequent instillation and minimizing side effects, thus improving patient compliance and symptom management.
Implementation Method 1
Chitosan, a polycationic polymer which is derived from the natural polymer chitin, is well known for its mucoadhesive properties. Ocular residence time of ophthalmic formulations containing chitosan can be increased not only due to its viscosity enhancing properties but also because of interactions of chitosan with negatively charged mucins on the ocular surface
Implementation Method 2
The use of thiolated polysaccharides for preparing an implant for tissue augmentation is disclosed in WO 2008/077172, wherein said thiolated polymers are characterised by the formation of disulfide bonds which leads to a stabilisation of the polymeric network
Implementation Method 3
These polymers are intended to protect ocular mucous membranes and provide lubrication for the ocular surface
Data Source
AI summary
The present invention relates to a sterile aqueous ophthalmic solution comprising N-(N- acetylcysteinyl-)chitosan or a pharmaceutically acceptable salt thereof in a carrier solution, wherein the N-(N-acetylcysteinyl-)chitosan has a content of free thiol groups in an amount of from 80 μmol/g polymer to 280 μmol/g polymer, for the specific use in the prevention or treatment of dry eye syndrome or dry eye signs and/or symptoms wherein said solution is applied prior to sleep.