Vacuum Sterilization Using Hydrogen Peroxide and Ozone
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Solution Overview
Problem
Conventional sterilization methods using gaseous biocides under vacuum face challenges such as water vapor condensation interfering with the sterilizing action, high ozone levels damaging articles, and unsatisfactory results for articles with long internal lumens, leading to increased costs and cycle times.
Innovation Solution
A method involving sequential exposure of articles to a conditioning agent and a sterilant gas under vacuum, where the conditioning agent initiates free radical formation, allowing for reduced sterilant usage and shorter cycle times without humidification control, utilizing hydrogen peroxide and ozone gases effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water vapor is present in the sterilization atmosphere during hydrogen peroxide sterilization, then the sterilization process can proceed, but water vapor condenses on articles and interferes with the sterilizing action of hydrogen peroxide
Solution Approach 1:
The article is pre-exposed to the conditioning agent (hydrogen peroxide) before the sterilant (ozone) is applied. This preliminary conditioning creates free radicals on the article surface that enhance the subsequent sterilization effectiveness, allowing for reduced sterilant usage and shorter cycle times while preventing water vapor condensation interference through the vacuum process
2Reliability
If high levels of ozone gas are used to achieve complete sterilization, then sterilization effectiveness is improved, but articles are damaged and sterilization cost increases
Solution Approach 1:
The article is pre-conditioned with hydrogen peroxide to generate free radicals on the surface before ozone application. This preliminary action creates reactive sites that dramatically reduce the ozone concentration needed for complete sterilization, preventing material damage while achieving sterilization effectiveness
Solution Approach 2:
The invention changes the chemical state of the article surface by introducing free radicals through hydrogen peroxide decomposition. This parameter change in the article's surface chemistry enables much lower ozone doses (reduced concentration parameter) to achieve the same sterilization effect, avoiding material damage
3Reliability
If conventional sterilization methods are used for articles with long internal lumens, then sterilization can be achieved, but cycle times increase and costs increase
Solution Approach 1:
The invention uses vacuum pressure to facilitate the penetration of gaseous sterilants into long internal lumens. By maintaining vacuum conditions during the sterilization process, the gas molecules can more effectively reach into deep cavities and long passages, reducing the time required for complete sterilization of complex geometries
Solution Approach 2:
The combination of hydrogen peroxide and ozone creates a powerful oxidative environment that rapidly sterilizes difficult-to-reach areas. The free radicals generated accelerate the oxidation process, enabling complete sterilization of long lumens in shorter cycle times compared to conventional 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 significantly reduces sterilant usage and cycle times, achieves complete sterilization with lower ozone doses, and is compatible with both stainless-steel and heat-sensitive instruments, eliminating the need for separate sterilizers and minimizing environmental impact.
Implementation Method 1
The conditioning agent initiates the formation of free radicals and accelerates the formation of further radicals by the sterilant
Implementation Method 2
The ozone gas is generally produced externally to the sterilization chamber and supplied into the chamber under vacuum to increase penetration of the sterilant gas into restricted spaces on the articles to be sterilized
Implementation Method 3
The hydrogen peroxide is generally supplied as an aqueous solution and evaporated prior to injection into a sterilization chamber of the sterilizer, by heating of the solution, or by applying a vacuum to the sterilization chamber
Data Source
AI summary
Disclosed is a method of sterilizing an article by sequentially exposing the article under vacuum first to a gaseous conditioning agent for forming radicals and then to a sterilant. The preferred conditioning agent is hydrogen peroxide and the preferred sterilant is ozone. The chamber is initially evacuated to a first vacuum pressure and then sealed for the remainder of the sterilization process and during all sterilant injection cycles, without removal of any component of the sterilization atmosphere, which means without any measures to reduce the water vapor content. Keeping the chamber sealed and maintaining the conditioning agent and the radicals generated thereby in the chamber for the sterilization with sterilant results in a synergistic increase in the sterilization efficiency and allows for the use of much lower sterilant amounts and sterilization cycle times than would be expected from using the conditioning agent and the sterilant in combination.