Non-Glass Prefilled Syringe Barrier Materials for EtO pH Stability
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Solution Overview
Problem
Plastic syringes used for prefilled fluids are susceptible to pH shifts and residual toxic byproducts during ethylene oxide (EtO) sterilization, while glass syringes are fragile and costly, complicating sterilization and increasing logistical challenges.
Innovation Solution
A syringe assembly made from cyclic olefin polymer (COP) or cyclic olefin copolymer (COC) with a high gas impermeability barrier, combined with a plunger and tip cap made from materials like polypropylene and butyl rubber, prevents EtO ingress and maintains solution pH within acceptable ranges during sterilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plastic syringes are used for prefilled fluids, then manufacturing cost is reduced and ease of manufacture is improved, but pH stability deteriorates and toxic byproducts are generated during EtO sterilization
Solution Approach 1:
The patent changes the material parameter from conventional polypropylene to cyclic olefin polymer (COP) or cyclic olefin copolymer (COC), which have different chemical properties including higher resistance to EtO sterilization and better pH stability, thereby resolving the contradiction between ease of manufacture and pH stability
Solution Approach 2:
The syringe assembly uses composite material construction with COP/COC barrel combined with specific plunger and tip cap materials, creating a multi-material system that maintains manufacturing simplicity while achieving superior chemical stability and EtO resistance
2Stability of the object's composition
If glass syringes are used for prefilled fluids, then pH stability is improved and EtO ingress is prevented, but device complexity increases and logistical challenges worsen
Solution Approach 1:
The patent employs disposable plastic syringes made from COP/COC that can be sterilized with EtO gas, replacing fragile glass syringes. These single-use devices maintain pH stability and prevent EtO ingress while eliminating the complexity of glass handling, storage, and disposal logistics
Solution Approach 2:
The invention changes the material parameter from glass to COP/COC plastic, which provides comparable pH stability and EtO resistance but with significantly reduced device complexity, eliminating fragility issues and simplifying manufacturing and logistics
3Ease of manufacture
If conventional polypropylene is used for syringe barrel, then ease of manufacture is improved, but EtO gas permeability increases causing pH shift and toxic residue
Solution Approach 1:
The patent changes the material parameter from polypropylene to cyclic olefin polymer (COP) or cyclic olefin copolymer (COC), which have lower gas permeability to EtO, thereby preventing EtO ingress while maintaining ease of manufacture through injection molding processes
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 solution maintains the pH of the solution within the syringe assembly within the required range of 4.5-7.0, adhering to USP standards and FDA residue limits, ensuring the syringe assembly remains sterile and effective without adverse chemical changes.
Implementation Method 1
A syringe assembly made from cyclic olefin polymer (COP) or cyclic olefin copolymer (COC) with a high gas impermeability barrier
Data Source
AI summary
A method of sterilizing a prefilled syringe comprises assembling a syringe assembly and performing at least one ethylene oxide (EtO) sterilization procedure cycle. The assembling step includes inserting a tip cap at a first end of a plunger, filling a non-glass barrel with sterilization sensitive material at a second end of the barrel, and inserting the plunger into the barrel at a second end to seal the sterilization sensitive material within the barrel. The EtO sterilization procedure cycle comprises undergoing a preprocessing stage, a wash and conditioning stage, an EtO sterilization stage and a wash and post exposure stage. Upon completing the EtO sterilization procedure cycle, a resultant pH of the sterilization-sensitive material does not exceed an acceptable pH range as defined by the United States Pharmacopeia. The disclosure also discusses inserting an assembled prefilled syringe into a procedure tray prior to performing the EtO sterilization procedure cycle.