Diclofenac Sodium Medical Plaster Sustained Release Matrix
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Diclofenac sodium salt is unsuitable for use in medical plasters with PSA matrices based on Eudragit NE40 due to minimal release, making it ineffective for prolonged therapeutic effects, unlike its diethylammonium salt counterpart.
Innovation Solution
A medical plaster formulation using a PSA matrix composed of ethyl acrylate and methyl methacrylate copolymers with citric acid esters and butylhydroxyanisole, which allows for the continuous release of diclofenac sodium at therapeutically active concentrations for 24 hours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diclofenac sodium salt is used in a PSA matrix based on Eudragit NE40, then the plaster formulation is simplified and safety is improved, but the active ingredient release is minimal and ineffective for prolonged therapeutic effects
Solution Approach 1:
The patent changes the chemical parameters of the PSA matrix by incorporating citric acid esters (particularly tributyl citrate) and butylhydroxyanisole alongside the Eudragit NE40 copolymer. This compositional modification alters the matrix properties to enable sustained release of diclofenac sodium salt over 24 hours, resolving the contradiction between using a simplified formulation and achieving prolonged therapeutic effectiveness.
2Speed
If diclofenac is formulated to penetrate through the corneum stratum, then skin permeability is improved, but solubility in underlying tissue is reduced due to high partition coefficient
Solution Approach 1:
The patent uses citric acid esters, particularly tributyl citrate, as intermediary substances in the PSA matrix. These esters facilitate the transition of diclofenac from its acid form (high partition coefficient) to its salt form, enabling both effective penetration through the corneum stratum and adequate solubility in the underlying tissue, thus resolving the contradiction between penetration speed and tissue solubility.
3Ease of operation
If the plaster remains on skin for extended periods, then patient compliance is improved, but adhesion reliability may be compromised
Solution Approach 1:
The patent creates a composite PSA matrix combining Eudragit NE40 copolymer with citric acid esters and butylhydroxyanisole. This composite material maintains strong adhesion to skin over extended periods (24 hours) while ensuring continuous release of therapeutically active concentrations of diclofenac, thus resolving the contradiction between extended wear time for patient compliance and maintaining adhesion reliability.
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 ensures a prolonged, constant release of diclofenac sodium, comparable to market-leading products, improving patient compliance by requiring replacement only once daily without causing skin irritation or toxicity.
Implementation Method 1
the active ingredient is gradually released and, after passing through the skin, it reaches the bloodstream in a therapeutically active quantity
Implementation Method 2
a polymeric adhesive matrix, called 'Pressure Sensitive Adhesive' (PSA)
Data Source
Figure 1
AI summary
A slow-release medical plaster is described, based on diclofenac, specifically a medical plaster based on diclofenac sodium salt, whose formulation allows the release of the active ingredient continuously and at locally therapeutically active concentrations over 24 hours, and also the polymer adhesive matrix (PSA) for use in a medical plaster based on diclofenac sodium salt.