Ketoprofen Patch Zinc Complex Stabilization
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Solution Overview
Problem
Nonsteroidal anti-inflammatory analgesics like ketoprofen, when combined with L-menthol in patches, face stability issues due to the formation of menthol esters and crystal precipitation, and existing solutions that add metal compounds hinder drug release.
Innovation Solution
A patch comprising ketoprofen, L-menthol, zinc oxide, and a fatty acid ester, which suppresses menthol ester production and crystal precipitation while maintaining excellent skin permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If metal compounds (metal oxides, metal hydroxides, metal carbonates) are added to suppress menthol ester formation, then stability is improved, but drug release from patches is suppressed
Solution Approach 1:
The patent changes the type of metal compound from conventional metal oxides/hydroxides/carbonates to a specific complex compound containing zinc ion and organic acid (where the organic acid is a hydroxy acid or amino acid). This parameter change in chemical composition allows the zinc complex to suppress menthol ester formation while maintaining drug release capability, resolving the contradiction between stability and productivity
Solution Approach 2:
The invention uses a composite material approach by forming a complex compound between zinc ion and organic acid (hydroxy acid or amino acid). This composite structure provides both the stability function of metal compounds and the compatibility needed for drug release, overcoming the limitations of simple metal oxides/hydroxides/carbonates
2Ease of operation
If L-menthol is blended in patches with ketoprofen, then refreshing effect is improved, but menthol ester formation occurs reducing drug stability
Solution Approach 1:
The zinc complex compound acts as an intermediary substance between ketoprofen and L-menthol. It suppresses the direct reaction between ketoprofen's carboxylic acid group and L-menthol that would form menthol esters, thereby preventing drug degradation while allowing L-menthol to maintain its refreshing effect on the skin
3Duration of action of stationary object
If ketoprofen is stored over time in patches, then cumulative effect is improved, but crystal precipitation occurs reducing efficacy
Solution Approach 1:
The zinc complex compound serves as a stabilizing intermediary that prevents crystal precipitation of ketoprofen during long-term storage. By coordinating with ketoprofen molecules, it maintains them in a stable state and prevents crystallization, allowing the drug to maintain its amorphous state and efficacy over extended storage periods
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 patch effectively prevents menthol ester formation and crystal precipitation, ensuring stability and efficient drug release over time, while maintaining skin permeability.
Implementation Method 1
ketoprofen and L-menthol react to produce menthol esters, and it has long been known that problems occur in the stability of the drug... the addition of the above metal compounds suppresses drug release from the patches
Implementation Method 2
when a patch comprising ketoprofen and L-menthol also comprises zinc oxide as well as a fatty acid ester, such patch can suppress the production of a menthol ester of ketoprofen and yet shows excellent skin permeability
Implementation Method 3
the present inventor has also found that the present invention can also suppress crystal precipitation of ketoprofen with time
Data Source
AI summary
The present invention provides a patch which prevents ketoprofen from forming a menthol ester, suppresses crystal precipitation, and yet shows excellent skin permeability. Specifically, the present invention provides a patch comprising ketoprofen, L-menthol, zinc oxide, and a fatty acid ester in a pasty preparation.