Propylene Elastomer Seal for pMDI Extractables Reduction
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Solution Overview
Problem
Existing seal materials for pharmaceutical dispensing devices, such as pMDIs, face challenges with chemical compatibility, tensile strength, permanent compression set, stress relaxation, and low permeability, while also requiring low levels of extractables and leachables to prevent contamination and reaction with drug products, and current curing processes can result in brittle materials and residual by-products that interfere with drug mechanisms.
Innovation Solution
A seal material composed of a polyolefin thermoplastic elastomer with isotactic propylene crystallinity, preferably a copolymer or terpolymer of propylene and alpha-olefins, combined with additional thermoplastic components and mineral/inorganic fillers, which can be produced without cross-linking agents, plasticizers, or processing aids, offering improved elastomeric properties and reduced extractables and leachables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional elastomeric seal materials (such as nitrile rubber) are used, then good sealing characteristics and elasticity are achieved, but high levels of extractables and leachables are present which can contaminate drug products
Solution Approach 1:
The patent changes the chemical composition parameters of the seal material by using a thermoplastic elastomer with specific propylene content (50-90 wt%) and isotactic crystallinity (10-40%), which fundamentally alters the material's extractables profile while maintaining sealing performance
Solution Approach 2:
The patent employs a composite material system consisting of thermoplastic elastomer blended with compatible polymers and filled with inorganic materials, creating a multi-component seal material that achieves both low extractables and good sealing characteristics
2Reliability
If peroxide curing is used to cross-link elastomers, then non-permeability and physical properties are improved, but the material can become brittle and residual by-products interfere with drug mechanisms
Solution Approach 1:
The patent removes the harmful peroxide curing step and associated cross-linking chemistry from the seal material formulation, eliminating the source of brittle behavior and residual by-products that interfere with drug mechanisms
Solution Approach 2:
The patent uses a thermoplastic elastomer that can be processed and disposed of without requiring long-term durability through cross-linking, allowing for simpler processing and elimination of harmful residues
3Manufacturing precision
If extraction processes are used to remove surface residues and by-products, then material purity is improved, but extraction times are prolonged and material properties deteriorate
Solution Approach 1:
The patent performs preliminary action by formulating the seal material to inherently minimize the formation of extractables and by-products during manufacturing, eliminating the need for prolonged post-manufacturing extraction processes
4Reliability
If conventional curing and moulding processes are used, then seal material properties are achieved, but production cycles are lengthy and costs increase
Solution Approach 1:
The patent replaces the chemical curing system with a thermoplastic processing system that uses heat and shear during injection molding to achieve final material properties, eliminating the time-consuming separate curing step and accelerating production
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 seal material maintains excellent sealing characteristics and reduces extractables and leachables, ensuring compatibility and stability under pharmaceutical conditions, with manufacturing benefits including faster production cycles and reduced waste, and is suitable for use in pMDIs and other pharmaceutical dispensing devices.
Implementation Method 1
a thermoplastic elastomer including a propylene component with isotactic crystallinity
Data Source
AI summary
A seal for a valve for use in a pharmaceutical dispensing device, which seal is formed from a thermoplastic elastomer including a propylene component with isotactic crystallinity.