Cationic Ophthalmic Emulsions for Prostaglandin Stability
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Solution Overview
Problem
Current ophthalmic prostaglandin formulations face challenges with chemical instability and toxicity, particularly with the use of quaternary ammonium preservatives, and struggle to maintain effective drug bioavailability and stability over extended periods, such as exceeding one year.
Innovation Solution
A cationic ophthalmic oil-in-water emulsion is developed, featuring a positively charged interfacial film with cationic agents like benzalkonium chloride and non-ionic surfactants, which encapsulates prostaglandins like latanoprost in an oily core, avoiding water-soluble polymers and maintaining a low cation content to enhance chemical stability and bioavailability while minimizing toxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quaternary ammonium preservatives are used in prostaglandin formulations, then preservation effectiveness is improved, but toxicity increases
Solution Approach 1:
The patent removes quaternary ammonium preservatives from the formulation entirely, extracting the harmful preservative component while maintaining preservation effectiveness through alternative means (sterile filtration and aseptics during manufacturing).
Solution Approach 2:
The patent employs single-use sterile containers or implements sterile filtration systems that provide preservation through physical barriers rather than chemical preservatives, eliminating long-term toxicity concerns.
2Quantity of substance
If prostaglandin concentration is maintained in formulation, then therapeutic efficacy is improved, but chemical stability deteriorates over time
Solution Approach 1:
The patent introduces specific excipients and antioxidants that act as intermediaries to protect prostaglandin molecules from degradation. These substances mediate between the prostaglandin and environmental factors causing degradation, maintaining both concentration and stability.
Solution Approach 2:
The patent optimizes formulation parameters including pH, ionic strength, and temperature conditions to create an environment where prostaglandin remains stable at therapeutic concentrations over extended periods.
3Productivity
If cationic emulsions are used to increase drug bioavailability, then electrostatic attraction to eye surface is improved, but emulsion stability becomes difficult to maintain
Solution Approach 1:
The patent applies cationic charge selectively at the emulsion droplet surface through surface-active agents, while the bulk emulsion maintains stability. This localized charging provides eye surface attraction without compromising overall emulsion stability.
Solution Approach 2:
The patent uses composite emulsion systems combining cationic and non-ionic surfactants, or cationic lipids with stabilizing polymers, to achieve both electrostatic attraction for enhanced bioavailability and structural stability for long-term maintenance.
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 emulsion achieves enhanced chemical stability and bioavailability of prostaglandins, maintaining therapeutic efficacy with improved tolerability and stability over extended periods, as demonstrated by real-time and accelerated stability studies, and shows comparable efficacy to commercial products in reducing intraocular pressure.
Implementation Method 1
they have the advantage of increasing the bioavailability of the drugs by electrostatic attraction between the emulsions's positive charge and the negatives charges carried at the eye surface
Implementation Method 2
One known approach to stabilize an emulsion is to confer an electrostatic charge to the droplets surface which will result in droplet repulsion and less droplet coalescence
Data Source
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AI summary
The present invention relates to cationic ophthalmic oil-in- water type emulsions, which comprise colloid particles having an oily core surrounded by an interfacial film, said emulsion comprising at least one cationic agent and at least one non ionic surfactant, said oily core comprising a prostaglandin selected from the group comprising in particular latanoprost, unoprostone isopropyl, travoprost, bimatoprost, tafluprost, 8-isoprostaglandinE2, or a mixture thereof, for treating ocular hypertension and/or glaucoma. These emulsions have the property to increase the chemical stability of prostaglandins.