Ketoprofen Gel Patch Adhesion Stability via Propylene Glycol Ratio
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Solution Overview
Problem
Gel patches containing ketoprofen face issues with storage stability due to conversion into ester analogues during storage and adhesion strength reduction over time, leading to potential skin irritation and increased peel strength after application.
Innovation Solution
A gel patch formulation with a paste layer comprising ketoprofen, propylene glycol, 1-menthol, and water, where propylene glycol is 3-fold the mass of ketoprofen or less, and including poly(methyl acrylate/2-ethylhexyl acrylate) and poly(methacrylic acid/n-butyl acrylate), along with fatty acid alkyl esters and alkylene dicarboxylic acid esters, to maintain adhesion strength and reduce peel strength increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If poly(methyl acrylate/2-ethylhexyl acrylate) is added to improve adhesion strength, then adhesion strength increases, but peel strength becomes excessively high causing skin irritation
Solution Approach 1:
The patent adjusts the molecular weight, softening point, and composition ratio of poly(methyl acrylate/2-ethylhexyl acrylate) to optimize the balance between adhesion strength and peel strength. By changing these parameters, the adhesive maintains strong bonding while reducing excessive peel force that causes skin irritation
Solution Approach 2:
The patent creates a composite adhesive system combining poly(methyl acrylate/2-ethylhexyl acrylate) with other polymers and additives to achieve balanced adhesion properties. This composite approach allows the adhesive to maintain strong bonding while controlling peel strength to prevent skin irritation
2Duration of action of moving object
If the gel patch is applied for a long time, then therapeutic effect is maintained, but adhesion strength decreases over time
Solution Approach 1:
The patent formulates the adhesive to maintain continuous effective adhesion throughout the therapeutic period. The adhesive composition and structure are designed to prevent adhesion loss over time, ensuring the gel patch remains securely attached for the full duration of therapeutic action
Solution Approach 2:
The patent uses a specific ratio of poly(methyl acrylate/2-ethylhexyl acrylate) that provides sufficient adhesion strength beyond what is minimally required, ensuring the patch maintains its position even as skin conditions change during prolonged application
3Stability of the object's composition
If propylene glycol is added to stabilize ketoprofen, then storage stability improves, but excessive propylene glycol may cause skin irritation
Solution Approach 1:
The patent optimizes the concentration of propylene glycol within a specific range to achieve adequate ketoprofen stabilization while maintaining skin compatibility. By precisely controlling this parameter, the formulation prevents both drug degradation and skin irritation
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 formulation provides excellent storage stability for ketoprofen, maintaining adhesion strength and reducing peel strength increase, ensuring a prolonged therapeutic effect and improved skin permeability while minimizing skin irritation.
Implementation Method 1
a part of ketoprofen is easily converted into an ester analogue due to a transesterification or the like during storage of the gel patch
Implementation Method 2
the gel patch tends to reduce the skin permeability of the drug compared with a tape agent
Implementation Method 3
the adhesion strength of the gel patch often decreases with the elapse of time after application
Data Source
AI summary
The present invention provides a gel patch having a paste layer on a support, wherein the paste layer comprising ketoprofen or a pharmaceutically acceptable salt thereof, propylene glycol, 1-menthol, and water, wherein the mass of propylene glycol in the paste layer is 3-fold the mass of ketoprofen or less, and wherein the content of 1-menthol based on a total mass of the paste layer is 0.1 to 0.5 mass %.