KMN Science Popularization | Common Sterilization Methods and Sterilization Validation Content for Aseptic Medical Devices

The sterilization of sterile medical devices is a crucial step in ensuring their safety and effectiveness. By selecting appropriate sterilization methods and conducting rigorous sterilization validation, we can ensure that medical devices meet sterile standards before use, providing patients with safer and more reliable medical services.

Dry heat sterilization method

Dry heat sterilization method refers to the method of placing items in a dry heat sterilization cabinet (box) and using dry heat air to kill microorganisms or eliminate pyrogenic substances.

Sterilization principle:

Mainly based on the destructive effect of high temperature on biomolecules (such as proteins, nucleic acids, etc.) inside microorganisms. By heating, proteins in microorganisms can denature or coagulate, nucleic acids can be destroyed, enzymes can lose activity, leading to microbial death. Specifically, high temperatures can disrupt the hydrogen bonds between bacterial proteins and nucleic acids, causing changes in the spatial conformation of proteins and the loss of their original biological functions; At the same time, the double helix structure of nucleic acids will also be disrupted, making it impossible to replicate and transcribe genetic information; Enzymes, as biocatalysts, are also inhibited or destroyed by high temperatures and cannot catalyze biochemical reactions anymore.

Scope of application:

① High temperature resistant items: such as glassware (test tubes, petri dishes, straws, syringes, etc.), metal utensils (such as steel pipes for measuring potency, needles, tweezers, scissors, etc.), etc. These items can withstand high temperatures without deformation or damage, making them suitable for treatment using dry heat sterilization.

② Items that do not allow moisture to penetrate, such as certain oil-based materials (such as oil-based ointment mechanisms, injection oils, etc.) and powdered chemicals. These items are not easily changed at high temperatures, but moisture is not allowed to penetrate, so using dry heat sterilization can avoid the adverse effects of moisture on them.

③ Other special items: such as chemicals that must be kept dry, sharp instruments, etc. These items need to be kept dry during the sterilization process to prevent chemical reactions or damage to the cutting edge.

Wet heat sterilization method

Wet heat sterilization refers to the method of sterilization using saturated steam, boiling water, or circulating steam.

Sterilization principle:

The main method is to use high-temperature and high-pressure water vapor as a medium, which has the characteristics of high latent heat and strong penetration, to deform the proteins and nucleic acids of microorganisms, ultimately leading to their death. Specifically, when water vapor comes into contact with microorganisms, its high temperature will break the hydrogen bonds between proteins and nucleic acids in the microbial body, causing changes in the spatial conformation of proteins and loss of their original functions; At the same time, the double helix structure of nucleic acids will also be disrupted, making it impossible to replicate and transcribe genetic information. This deformation can be reversible or irreversible, but when the number of hydrogen bond ruptures reaches the critical value for microbial death, the microorganisms are killed, thus achieving the sterilization effect.

Category:

The wet heat sterilization method can be further divided into high-pressure steam sterilization method, circulating steam sterilization method, intermittent steam sterilization method, boiling sterilization method, pasteurization method, etc. Among them, high-pressure steam sterilization is the most commonly used sterilization method in the production process of pharmaceutical preparations. From surgical instruments to medical fabrics, high-pressure steam sterilization has been widely used in the medical industry due to its strong sterilization ability and stable performance.

Scope of application:

The wet heat sterilization method is widely used for sterilization of various items and materials due to its advantages of high efficiency, reliability, and easy operation.

① Items that are resistant to moisture and high temperatures, such as metal, enamel, glass, and rubber materials. These items can remain stable in hot and humid environments and will not deform or be damaged due to high temperature and humidity.

② Pharmaceutical preparation production: Wet heat sterilization is the most commonly used sterilization method in the pharmaceutical preparation production process, as it can effectively kill microorganisms while maintaining the stability and activity of the drug.

③ In other occasions that require sterilization, such as laboratories, hospitals, etc., items and instruments that require a sterile environment can also be treated using moist heat sterilization method.

Gas sterilization method

Gas sterilization method is a method of sterilization using gas disinfectants, which uses the sterilizing gas generated by the gas disinfectant to disinfect the surface of objects and air in a closed space. Such as ethylene oxide sterilization, gaseous hydrogen peroxide sterilization, ozone sterilization

Sterilization principle:

The gas sterilization method mainly relies on the diffusion and penetration of chemical disinfectants. These disinfectants (such as ethylene oxide, formaldehyde, ozone, etc.) can release gases under specific conditions, which can penetrate into the interior of microbial cells, destroy their biological structures such as proteins, nucleic acids, etc., and lead to microbial death. Specifically, gas sterilization achieves sterilization through the following methods:

① Diffusivity: Disinfectant gas can quickly diffuse to every corner of the item to be sterilized, ensuring comprehensive sterilization.

② Penetration: Disinfectant gas can penetrate the tiny pores and gaps of objects, killing hidden microorganisms.

④ Chemical reaction: Disinfectant gas reacts chemically with the cellular components of microorganisms, damaging their structure and function, leading to microbial death.