Siliconized Backing Layer for Transdermal Adhesion
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Solution Overview
Problem
Transdermal therapeutic systems with silicone adhesives experience inadequate adhesion to the backing layer, leading to adhesive residue and dark margins on the skin due to the apolar nature of silicone adhesives and their tendency to 'cold flow', especially when exposed to heat.
Innovation Solution
A siliconized backing layer is created by coating organopolysiloxanes containing vinyl groups and Si—H groups onto the backing layer, followed by heat treatment with a platinum catalyst to form a firmly anchored organopolysiloxane layer, enhancing adhesion and preventing adhesive spread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicone adhesives are used in the polymer layer, then the system provides effective transdermal delivery, but adhesion to the backing layer is inadequate due to apolar nature
Solution Approach 1:
A silane-modified polymer layer is introduced as an intermediary between the polar backing layer and the apolar silicone adhesive. This intermediate layer contains both polar groups (for adhesion to backing layer) and non-polar silicone groups (for compatibility with silicone adhesive), resolving the adhesion incompatibility.
Solution Approach 2:
The polymer layer is formulated as a composite material containing silane-modified polymers that combine polar and non-polar characteristics. This composite structure enables simultaneous adhesion to both the polar backing layer and the apolar silicone adhesive, preventing adhesive emergence.
2Productivity
If heat is applied to accelerate active ingredient delivery, then transdermal delivery efficiency improves, but adhesive cold flow and spreading increase
Solution Approach 1:
The silane-modified polymer layer is applied in advance to the backing layer before the silicone adhesive is applied. This pre-prepared intermediate layer creates a stable adhesion interface that resists thermal disruption, cushioning against the harmful effects of heat-induced adhesive softening and cold flow.
3Ease of manufacture
If the backing layer is made from polyethylene terephthalate, then manufacturing is simplified, but adhesion to silicone adhesive is poor due to polarity mismatch
Solution Approach 1:
The silane-modified polymer layer is applied locally to the surface of the backing layer, creating a specialized adhesion interface only where needed. This maintains the simple PET backing layer structure for easy manufacturing while adding localized functional quality for improved adhesion.
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 siliconized backing layer significantly improves adhesion and reduces adhesive residue and dark margin formation, even under heat conditions, making systems with silicone adhesives more effective and feasible, such as microreservoir systems.
Implementation Method 1
coating organopolysiloxanes containing vinyl groups and organopolysiloxanes containing functional Si—H groups in a mixture onto the film that is to be treated, in a coating operation in the presence of a platinum catalyst, with a heat treatment resulting in formation of an organopolysiloxane layer that adheres firmly to the substrate
Implementation Method 2
in the presence of a platinum catalyst, with a heat treatment resulting in formation of an organopolysiloxane layer
Implementation Method 3
with a heat treatment resulting in formation of an organopolysiloxane layer that adheres firmly to the substrate
Data Source
AI summary
The invention relates to a transdermal therapeutic system which comprises a backing layer, an adhesive layer, a polymer layer and a removable protective layer. The adhesive layer is an organosiloxane layer and is anchored in the backing layer by siliconization.