Diclofenac Sodium Patch Crystallization Suppression
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Solution Overview
Problem
Diclofenac sodium patches face issues with time-dependent crystallization and skin permeability, limiting their effectiveness in providing systemic analgesic and anti-inflammatory relief due to insufficient solubility and skin absorption.
Innovation Solution
A patch comprising a support layer and an adhesive layer with diclofenac sodium, dimethyl sulfoxide, and citric acid at specific mass ratios, which suppresses crystallization and enhances skin permeability, using a styrene-isoprene-styrene block copolymer as the adhesive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If diclofenac sodium is compounded with organic acid such as citric acid in the pressure-sensitive adhesive material layer, then the solubility and skin permeability of diclofenac sodium are improved, but time-dependent crystallization of diclofenac or diclofenac sodium occurs in the adhesive layers
Solution Approach 1:
The patent introduces a specific solvent system comprising polyethylene glycol and propylene glycol as intermediary substances that mediate between diclofenac sodium and citric acid. This solvent system prevents direct crystallization while maintaining solubility enhancement, acting as a stabilizing medium that allows the active ingredient to remain in solution without precipitating over time.
Solution Approach 2:
The patent optimizes the concentration ratios of diclofenac sodium, citric acid, polyethylene glycol, and propylene glycol within specific ranges. By controlling these compositional parameters, the system maintains diclofenac sodium in a stable dissolved state, preventing crystallization while preserving the solubility and permeability benefits of the organic acid combination.
2Object-affected harmful factors
If diclofenac sodium is used in patches, then skin permeability is improved compared to oral administration, but the blood concentration of diclofenac remains insufficient for systemic disorders
Solution Approach 1:
The patent creates a composite adhesive material system combining diclofenac sodium with multiple components including polyethylene glycol, propylene glycol, and citric acid in specific ratios. This composite formulation enhances both skin permeability and drug release characteristics, enabling sufficient blood concentration achievement for systemic treatment while maintaining the advantages of topical application.
3Quantity of substance
If high concentration of diclofenac sodium is contained in patches, then effectiveness against systemic disorders is achieved, but crystallization occurs reducing stability
Solution Approach 1:
The patent employs polyethylene glycol and propylene glycol as intermediary solvent systems that enable high concentrations of diclofenac sodium to be maintained in a stable dissolved state. These intermediaries prevent crystallization even at high drug concentrations, allowing the patch to achieve systemic therapeutic effectiveness while maintaining compositional stability throughout the product shelf life.
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 achieves stable high-concentration diclofenac sodium delivery with reduced skin irritation and improved skin permeability, allowing for systemic analgesic and anti-inflammatory effects comparable to oral administration.
Implementation Method 1
dimethyl sulfoxide displays excellent skin permeability even for diclofenac sodium with low skin permeability
Implementation Method 2
to have superior releasability and skin permeability of the drug, and to make the blood concentration of diclofenac in the subjects of administration high
Data Source
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AI summary
A patch comprising a support layer and an adhesive layer, wherein the adhesive layer comprises diclofenac sodium, dimethyl sulfoxide, and citric acid; a mass ratio between the diclofenac sodium and the citric acid (mass of diclofenac sodium : mass of citric acid) is 1:0.15 to 1:0.45; and a mass ratio between the diclofenac sodium and the dimethyl sulfoxide (mass of diclofenac sodium : mass of dimethyl sulfoxide) is 1:0.75 to 1:3.