Laquinimod Stability via Light-Resistant Coatings
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Solution Overview
Problem
Laquinimod, a compound used in treating Multiple Sclerosis, forms an impurity (N-Ethyl-N-phenyl-1,2-dihydro-4,5-di-hydroxy-1-methyl-2-oxo-3-quinolinecarboxamide) when exposed to light, which is difficult to purify and affects the stability and efficacy of pharmaceutical compositions.
Innovation Solution
A process for preparing and purifying N-ethyl-N-phenyl-1,2-dihydro-4,5-di-hydroxy-1-methyl-2-oxo-3-quinolinecarboxamide involves reacting specific compounds with oxidizing agents, bases, or Lewis acids, followed by solvent removal and basic solution addition, and incorporating a light-resistant coating in pharmaceutical compositions to minimize impurity formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laquinimod is exposed to light during storage or processing, then the compound undergoes photo-degradation, but this forms an impurity (N-Ethyl-N-phenyl-1,2-dihydro-4,5-di-hydroxy-1-methyl-2-oxo-3-quinolinecarboxamide) that is difficult to purify and affects stability and efficacy
Solution Approach 1:
The patent applies preliminary action by incorporating light-resistant coatings on packaging containers before the photo-degradation can occur. The coating is applied to the container surface in advance, creating a protective barrier that prevents light from reaching the laquinimod compound during storage and handling, thereby preventing impurity formation before it can happen.
Solution Approach 2:
The light-resistant coating acts as an intermediary between the light source and the laquinimod compound. This coating layer absorbs or blocks harmful light wavelengths, serving as a mediator that protects the pharmaceutical compound from photo-degradation without requiring changes to the compound itself or the light source.
2Manufacturing precision
If conventional purification methods are used to remove the photo-degradation impurity, then some purification is achieved, but the impurity remains difficult to completely eliminate and affects product quality
Solution Approach 1:
The patent applies preliminary anti-action by preventing the formation of the impurity in the first place through light-resistant packaging, rather than attempting to remove it through complex purification processes. This approach opposes the harmful photo-degradation reaction before it can occur, eliminating the need for extensive purification efforts.
Solution Approach 2:
The patent converts the potential harm of light exposure into a benefit by using light-resistant coatings that selectively block harmful wavelengths while potentially allowing beneficial light properties to pass through. The coating transforms the packaging material into an active protective agent that specifically counteracts the photo-degradation pathway.
3Stability of the object's composition
If light-resistant packaging is implemented to prevent impurity formation, then compound stability is improved, but packaging complexity and cost increase
Solution Approach 1:
The patent applies this principle by using thin film coatings applied to the packaging container surface. These light-resistant coatings are applied as thin layers that provide effective light blocking properties without adding significant structural complexity or weight to the packaging. The coating can be applied directly to the container interior surface, maintaining a simple overall packaging structure.
Solution Approach 2:
The patent changes the optical parameters of the packaging material by applying coatings with specific light-absorbing or light-blocking properties. The coating material is selected to have appropriate optical characteristics that block the wavelengths causing photo-degradation while maintaining other desirable packaging properties such as transparency to other wavelengths, mechanical strength, and chemical compatibility.
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 process ensures the presence of the impurity is below detectable limits, maintaining the stability and effectiveness of laquinimod-based pharmaceutical compositions, particularly in light-resistant packaging, thereby ensuring consistent treatment efficacy for Multiple Sclerosis.
Implementation Method 1
a light-resistant coating wherein the coating is resistant to light with wavelength in the range of 310-400 nm
Implementation Method 2
reacting a compound having the structure: with an oxidizing agent when R1 is methyl, ethyl or —CF3
Data Source
AI summary
The subject invention provides a pharmaceutical composition containing laquinimod or a pharmaceutically acceptable salt thereof, and a compound of N-ethyl-N-phenyl-1,2-dihydro-4,5-di-hydroxy-1-methyl-2-oxo-3-quinolinecarboxamide or a salt thereof.