Multi-Layer Pharmaceutical Container Preservative Barrier
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Solution Overview
Problem
Existing plastic containers for storing pharmaceutical solutions with preservatives like phenol and m-cresol face challenges in maintaining concentration stability and barrier properties, leading to unwanted diffusion and degradation of active ingredients during storage.
Innovation Solution
A flexible, transparent container composed of a multi-layer film structure, where the inner and outer layers are joined with a tie layer, providing a water-tight, phenol-resistant, and m-cresol-resistant barrier that prevents significant concentration changes of preservatives and water over extended storage periods, and is sterilizable using methods like gamma irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If plastic materials like PE, PP, or PET are used to store aqueous compositions with preservatives, then flexibility and transparency are improved, but preservative loss through diffusion and adsorption increases
Solution Approach 1:
The patent employs a composite material structure consisting of multiple layers: an inner layer (PE or PP) providing flexibility and compatibility with preservatives, and an outer layer (PCTFE) providing exceptional barrier properties against preservative diffusion. This composite structure resolves the contradiction by combining the advantages of different materials while mitigating their individual disadvantages.
Solution Approach 2:
Different layers of the container wall are assigned different material properties tailored to specific functions: the inner layer contacts the aqueous composition and provides flexibility, while the outer layer provides the primary barrier against preservative loss. This local differentiation of material qualities allows each layer to optimize its specific function without compromising the other.
2Strength
If polyurethane adhesives are used to laminate welding layers to PCTFE, then bonding strength is improved, but preservative migration to the adhesive increases
Solution Approach 1:
The patent introduces a tie layer as an intermediary between the inner layer and the PCTFE outer layer. This tie layer serves as a mediator that provides strong bonding while having low affinity for preservatives, thus preventing preservative migration to the adhesive interface while maintaining structural integrity.
Solution Approach 2:
The patent extracts or removes the polyurethane adhesive from the laminate structure and replaces it with a tie layer that has different chemical properties. This extraction eliminates the harmful interaction between preservatives and polyurethane adhesives while maintaining the necessary bonding function through the tie layer's mechanical properties.
3Reliability
If glass containers are used to store aqueous compositions, then preservative stability is improved, but flexibility and portability are worsened
Solution Approach 1:
The patent uses flexible polymeric materials (PE, PP, PCTFE) to create a container that can be made into flexible pouches or reservoirs. These thin film structures provide adequate barrier properties to maintain preservative stability while enabling flexibility and portability, thus replacing rigid glass containers with flexible plastic alternatives.
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 container effectively maintains the concentration of pharmaceutical solutions, including preservatives, over 24 months at various temperatures, ensuring the stability and safety of the active ingredients, while meeting stringent health and safety regulations.
Implementation Method 1
the high mobility of preservatives in welding layer based on polymers like polyethylene... combined with a high affinity of the preservatives to the widely used adhesives based on polyurethane used for lamination of welding layer to a moist barrier like polychlorotrifluoroethylene... The result of tests of the known art plastic products containing a solution of a medicament with preservatives is that a fast and not desired reduction in the content of preservative in the medicated solution takes place
Implementation Method 2
the inner and outer layers are joined with a tie layer
Implementation Method 3
sterilizable using methods like gamma irradiation
Data Source
AI summary
A container consisting of at least two layers, the inner layer consisting of a PE or PP film and the PCTFE layer consisting of a PCTFE film, and the thickness of the PCTFE layer being about 40-100μm, which container is equipped with a device where the liquid can be lead out through when desired and which container is transparent, shows superior properties for storing liquid pharmaceutical compositions, especially insulin compositions containing preservatives.