Emulsifier-Stabilized Biphasic Matrix for Transdermal Drug Release
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Solution Overview
Problem
Microreservoir transdermal therapeutic systems (TTS) face issues with biphasic structure instability during manufacturing, leading to phase separation, uncontrolled active agent delivery, and variability in release rates due to shear forces and coalescence of inner phase deposits.
Innovation Solution
Incorporation of an emulsifier, such as polysiloxane, polyisobutylene, or ethoxylated castor oil, in the biphasic matrix layer to stabilize the inner phase deposits, controlling their size and distribution, and enhancing resistance to shear forces during the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the biphasic composition is stored for extended periods during manufacturing, then production flexibility is improved, but phase separation and coalescence of inner phase deposits occur
Solution Approach 1:
A surfactant is introduced as an intermediary substance between the inner phase and outer phase to prevent coalescence during storage. The surfactant forms a protective interface that maintains deposit stability over extended storage periods without affecting the biphasic structure's integrity
Solution Approach 2:
The interfacial tension between phases is modified by adding a surfactant, which changes the physical parameters of the system. This parameter change allows the composition to remain stable during storage while maintaining the ability to form proper deposits during coating
2Manufacturing precision
If shear forces are applied during coating to distribute inner phase deposits, then coating uniformity is improved, but deposit coalescence increases
Solution Approach 1:
The shear forces that cause coalescence are not eliminated but converted into a beneficial effect. By controlling the degree of coalescence through surfactant selection, the shear forces during coating are transformed into a mechanism that ensures uniform distribution of deposits across the coating surface
Solution Approach 2:
The rheological parameters of the composition are adjusted through surfactant addition, allowing the system to withstand shear forces during coating without excessive coalescence. The composition maintains appropriate viscosity and flow characteristics under shear stress
3Reliability
If inner phase deposits are made smaller to improve active agent delivery control, then release predictability is improved, but manufacturing complexity increases
Solution Approach 1:
The system uses self-assembly of surfactant molecules at the phase interface to automatically control deposit size and distribution. This self-service mechanism eliminates the need for complex external control systems or multiple processing steps to achieve uniform, small deposits
Solution Approach 2:
A composite coating composition is formulated that combines outer phase, inner phase, and surfactant in specific ratios. This composite material inherently produces controlled deposit sizes during coating without requiring additional manufacturing complexity
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 emulsifier stabilizes the biphasic structure, ensuring consistent and continuous active agent delivery, reducing variability, and improving the resistance to shear forces, thereby maintaining a stable and predictable release profile.
Implementation Method 1
Incorporation of an emulsifier, such as polysiloxane, polyisobutylene, or ethoxylated castor oil, in the biphasic matrix layer to stabilize the inner phase deposits
Implementation Method 2
the emulsifier stabilizes the biphasic structure, ensuring consistent and continuous active agent delivery
Data Source
AI summary
The present invention relates to a transdermal therapeutic system (TTS) comprising an active agent-containing layer structure comprising A) a backing layer and B) a biphasic matrix layer, the biphasic matrix layer having a) a continuous, outer phase having a composition comprising 70 to 100% by weight of at least one polymer, b) a discontinuous, inner phase having a composition comprising the active agent and a dissolver for the active agent in amount sufficient so that the active agent forms a solution with the dissolver in the inner phase and c) an emulsifier in an amount of 0.1 to 20% by weight based on the biphasic matrix layer, processes of manufacture and uses thereof, corresponding methods of treatments therewith.