Catheter Hydrophilic Coating Radiation Sterilization
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Solution Overview
Problem
Current methods for sterilizing urinary catheters with hydrophilic coatings are cumbersome and can lead to chemical modification of the coating, increasing friction and reducing quality.
Innovation Solution
A method involving a catheter assembly with a hydrophilic coating and a high viscosity wetting medium, where the wetting medium does not contact the hydrophilic surface initially. The assembly is treated with electromagnetic or particle radiation, causing the wetting medium to decrease in viscosity and activate the hydrophilic surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radiation sterilization is applied to a catheter with hydrophilic coating, then sterilization is achieved, but the coating undergoes chemical modification increasing friction
Solution Approach 1:
A gel intermediary substance is introduced between the radiation source and the hydrophilic coating. The gel absorbs the radiation energy and converts it to heat, protecting the coating from direct radiation exposure while still achieving sterilization. This mediator prevents the harmful chemical modification of the coating while maintaining sterilization effectiveness.
Solution Approach 2:
The patent changes the physical state and properties of the wetting medium by transforming it from a liquid to a gel state before radiation exposure. This parameter change allows the medium to remain in place during sterilization and prevents coating modification. After sterilization, the gel can be converted back to liquid state for catheter activation.
2Ease of operation
If wetting medium is applied before radiation sterilization, then coating activation is achieved, but sterilization quality deteriorates due to coating modification
Solution Approach 1:
The catheter coating is pre-applied in its inactive, dry state before radiation sterilization. This preliminary action ensures the coating is in its most stable form during sterilization, preventing modification. The activation step is performed after sterilization, separating the coating application from the sterilization process to maintain coating quality.
Solution Approach 2:
The patent segments the catheter preparation process into distinct stages: coating application, sterilization (with gel protection), and post-sterilization activation. This segmentation allows each process to be optimized independently, ensuring coating quality is maintained during sterilization while still achieving catheter activation.
3Duration of action of stationary object
If liquid wetting medium is used during storage, then coating remains activated, but coating quality degrades over time
Solution Approach 1:
The patent utilizes phase transition of the wetting medium, transforming it from liquid to gel state during storage. In the gel state, the medium remains in place without degrading the coating. Upon use, the gel transitions back to liquid state to activate the coating. This phase transition allows long-term storage with coating protection while enabling activation when needed.
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 method ensures the hydrophilic coating remains intact during sterilization, maintaining low friction properties throughout the catheter's shelf life, thereby facilitating easy and comfortable insertion.
Implementation Method 1
whereby the wetting medium decreases in viscosity when submitted to electro-magnetic and/or particle radiation, allowing the wetting medium to flow within the catheter package to come into contact with and to thus activate the hydrophilic outer surface of the catheter
Implementation Method 2
the catheter is provided with a hydrophilic coating which is adhered to the outer surface of the catheter. Before insertion of the catheter, the hydrophilic coating is activated by swelling in contact with a hydrating liquid such as water.
Data Source
Figure 1a~1c
Figure 2a~2d
Figure 3a~3d
AI summary
The present invention refers to a method of making a ready-to-use catheter assembly, a catheter assembly for use in the method, and a wetting medium for use in the method. It is an object of the present invention to provide a ready-to-use catheter assembly which can be immediately used by a patient without the necessity for any preparation steps and a method of making such a ready-to-use catheter assembly which ensures that the catheter does not suffer from a loss of quality during its shelf life. Therefore, the method comprises the following steps: Placing a catheter with an inactivated hydrophilic outer surface at least along its insertable length and a wetting medium in a catheter package. Treating the catheter package with the catheter and the wetting medium with electro-magnetic and/or particle radiation while at least initially the hydrophilic outer surface at least along the insertable length of the catheter remains inactivated. Activating the hydrophilic outer surface at least along the insertable length of the catheter with the wetting medium during and/or after the radiation treatment and wherein the wetting medium decreases in viscosity when submitted to electro-magnetic and/or particle radiation. A ready-to-use catheter assembly comprises a catheter package, a catheter with a hydrophilic outer surface at least along its insertable length arranged in the catheter package and a wetting medium which is also arranged in the catheter package and which is in contact with the hydrophilic outer surface at least along the insertable length of the catheter so that the hydrophilic outer surface is activated and wherein the wetting medium is a gel comprising at least one solute polymer and has a viscosity below 1000cP, preferably 100cP.