Steam Sterilized Catheter Assembly with Partial Wetting
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Solution Overview
Problem
Current sterilization methods for hydrophilic urinary catheters, such as ethylene oxide gas and radiation, are costly, complex, and can deteriorate the catheter material or leave residues, while steam sterilization requires a fully filled package, making it heavy and prone to spillage, and existing solutions do not effectively address the need for a cost-efficient, compact, and safe sterilization method for pre-wetted catheters.
Innovation Solution
A medical device assembly with a hydrophilic surface is packaged in a sealed compartment with a small volume of wetting liquid (0.01-10% of the compartment volume) that allows steam sterilization, maintaining the catheter in a wetted state and reducing weight and spillage risks, while creating a humid atmosphere to extend shelf life and enable immediate use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ethylene oxide sterilization is used for dry catheter assemblies, then sterilization is cost-efficient, but the package must be gas permeable which lowers shelf life and allows moisture ingress that deteriorates the hydrophilic surface
Solution Approach 1:
The patent uses steam (water vapor) as the sterilizing atmosphere, which is inert to the hydrophilic coating and does not cause the same deterioration problems as ethylene oxide. The steam creates a humid environment that protects the hydrophilic surface while enabling sterilization, effectively replacing the harmful ethylene oxide gas environment with a beneficial steam environment.
2Reliability
If radiation sterilization is used, then sterilization is effective, but equipment is complex and costly and the radiation affects catheter material properties
Solution Approach 1:
The patent employs steam sterilization, which uses inexpensive water as the sterilizing agent compared to expensive radiation equipment. The steam is generated on-demand and condenses after use, representing a simple, low-cost, disposable-like approach that avoids the need for complex, expensive radiation sterilization infrastructure while achieving effective sterilization.
3Reliability
If steam sterilization is used for pre-wetted catheters with full package filling, then sterilization is effective, but the product becomes heavy and complex to produce with high spillage risk
Solution Approach 1:
The patent applies partial wetting instead of complete package filling. A small amount of wetting liquid (just enough to activate the hydrophilic coating) is introduced into the package, which is sufficient for sterilization purposes but avoids the excessive weight and spillage risks associated with filling the entire package with liquid. This partial action achieves the necessary sterilization effect without the drawbacks of full filling.
4Ease of operation
If the catheter is maintained in wetted state during storage, then the hydrophilic surface is ready-to-use, but conventional sterilization methods leave residues or require complex equipment
Solution Approach 1:
The patent changes the sterilization parameter from gas-phase (ethylene oxide) or radiation to steam phase, and changes the package state from dry to partially wet. This parameter change enables the catheter to be maintained in a wetted, ready-to-use state while using simple steam sterilization that leaves no harmful residues, unlike ethylene oxide or radiation methods.
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
This approach allows for efficient steam sterilization of pre-wetted catheters, extending shelf life to 3-5 years, ensuring the catheter is ready-to-use without additional wetting, and avoids the drawbacks of ethylene oxide and radiation methods by using commercially available and environmentally friendly steam sterilization equipment.
Implementation Method 1
the small volume of wetting liquid... creates a humid atmosphere to extend shelf life
Implementation Method 2
wherein said medical device assembly is steam sterilized
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A sterilized medical device assembly comprises a medical device 1 having a hydrophilic surface on at least a part thereof, such as a hydrophilic urinary catheter, and a package 3 forming a closed compartment accommodating the medical device. The medical device is arranged in an activated state in the package, with the hydrophilic surface being wetted with a wetting fluid 2. In addition, a small amount of wetting liquid is freely arranged in the closed compartment of the package, and in direct contact with the hydrophilic surface of the medical device. The volume of the wetting liquid corresponds to between 0.01% and 10% of a volume of the closed compartment. The medical device assembly is steam sterilized, and it has been found that the extra small amount of free liquid is very efficient in ensuring a reliable and efficient steam sterilization.