Diclofenac Aqueous Formulation With Isostearic Acid for Skin Absorption
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Solution Overview
Problem
Existing aqueous preparations for external use of diclofenac lack sufficient percutaneous absorbability and do not provide a good user experience.
Innovation Solution
An aqueous preparation comprising diclofenac, isostearic acid, tertiary alkanolamine, and a C2-6 aliphatic hydroxy acid, with specific molar ratios and pH range, using isopropanol and propylene glycol as solvents, and optionally including glycerin, to enhance percutaneous absorbability and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional aqueous preparations of diclofenac are used, then the preparation is simple and stable, but the percutaneous absorbability is insufficient
Solution Approach 1:
The patent employs a composite formulation containing diclofenac (or its salt) combined with isostearic acid and tertiary alkanolamine in specific molar ratios. This composite material approach creates a synergistic effect where the combination of these components significantly enhances percutaneous absorbability compared to conventional single-component aqueous preparations, while maintaining formulation stability through controlled pH (5.0-7.5) and specific compositional ratios.
Solution Approach 2:
The invention optimizes specific parameters including the molar ratio of tertiary alkanolamine to isostearic acid (0.6-1.2:1), the pH range (5.0-7.5), and the inclusion of C2-6 aliphatic hydroxy acids. By precisely controlling these parameters, the formulation achieves enhanced drug absorption through the skin while maintaining preparation stability and preventing degradation.
2Quantity of substance
If the percutaneous absorbability is improved by adding multiple components, then the absorption is enhanced, but the user experience and feeling in use deteriorates
Solution Approach 1:
The patent carefully adjusts the pH to a skin-compatible range (5.0-7.5) and controls the concentration of active components and excipients to ensure the preparation feels comfortable during application. The inclusion of C2-6 aliphatic hydroxy acids and optional glycerin further optimizes the sensory experience while maintaining enhanced absorption properties.
Solution Approach 2:
The formulation uses specific local components with targeted functions: isostearic acid and tertiary alkanolamine for absorption enhancement, C2-6 aliphatic hydroxy acids for pH adjustment and skin compatibility, and optional glycerin for improved sensory feel. Each component is optimized for its specific role to balance absorption enhancement with user comfort.
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 preparation exhibits excellent percutaneous absorbability and provides a good user experience, with rapid anti-inflammatory analgetic effects.
Implementation Method 1
an aqueous preparation for external use comprising Diclofenac or a salt thereof, isostearic acid, tertiary alkanolamine and a C 2-6 aliphatic hydroxy acid, wherein the content of the tertiary alkanolamine is within the range of 0.6 to 1.2 times by mol with respect to the content of the isostearic acid
Implementation Method 2
having an excellent percutaneous absorbability, and the preparation is expected to exhibit a sufficient anti-inflammatory analgetic effect in a short time
Implementation Method 3
the aqueous preparation comprises a combination of isopropanol and propylene glycol as a solvent with water
Data Source
Figure 1~2
AI summary
The purpose of the present invention is to provide an aqueous preparation for external use, said aqueous preparation comprising an acidic drug such as an arylacetic acid nonsteroidal anti-inflammatory analgesic, having an excellent percutaneous absorbability and giving a good feeling in use. The aqueous preparation for external use comprises the acidic drug or a salt thereof, isostearic acid and an alkanol amine. It is preferred that the aqueous preparation according to the present invention for external use further comprises a C2-6 aliphatic hydroxy acid and has a pH value of 4.5-7.8. The C2-6 aliphatic hydroxy acid is one member or a combination of the same selected from the group consisting of lactic acid, glycolic acid, malic acid, tartaric acid and citric acid.