1. Steam Sterilization
Steam Sterilization method is the most common method. It is a method involving Combination of moisture and temperature. The minimum temperature usually considered for steam sterilization is 121oC but lower temps can be used and the pressure must be shown to be equivalent to the temperatures obtained.
2. Dry heat Sterilization
In dry heat sterilization, lack of moisture requires an increase in temperature to be effective. Sterilization requires temps of 170°C versus 121°C for saturated steam. The belt speed for depyrogenation tunnels is variable so it must be controlled and validated for various vial sizes.
3. Ethylene Oxide for Sterilization
Ethylene Oxide for Sterilization requires “conditioning” of the load to carry the gas into the components. This process requires degassing phase to assure residual levels are within acceptable limits. Generally used with components that cannot take the temperatures of steam.
4. Gamma Radiation
Gamma radiation discovered in 1900 was used for industrial purposes in the 1950s with cobalt-60 as a radiation source. It is a very quick and efficient method of sterilization. It can adversely impact components of various plastics. Cycles based on bio-burden levels, quantity of load and packaging configurations. Cycles verified by “dosage” levels obtained throughout the load.
5. Chlorine Dioxide (CD) Gas Sterilization
Chlorine dioxide (CD) was discovered around the year 1811 and it gained extensive commercial use as a bleaching agent in the paper industry. The EPA recognized chlorine dioxide as a sterilizer in 1988. This opened the door for the applications of Chlorine dioxide in the medical field.
6. Hydrogen Peroxide Sterilization
Hydrogen peroxide has a long usage history in the pharmaceutical industry and is a highly accepted alternative to ethylene oxide (ETO). Hydrogen peroxide could be made use of in two ways: 1) vaporized hydrogen peroxide sterilization, 2) hydrogen peroxide plasma sterilization.
7. Hydrogen Peroxide Plasma Sterilization
This is a combination method of chemistry with physics. In this the hydrogen peroxide plasma sterilizer is first filled with the materials to be sterilized. The normal hydrogen peroxide plasma sterilization cycle comprises four stages (vacuum generation, diffusion, H2O2 injection and plasma discharge) and takes nearly 1 to 3 hours. No Aeration required. Once the cycle is complete, the sterilized devices are removed.
8. E-Beam Radiation
In this process, the Electron beam generator sends a high dose of electrons in a slim beam at the objects to be sterilized. The electrons emitted from the E-beam generator have insufficient penetrating power, less than gamma radiation.
9. Nitrogen Dioxide
Nitrogen Dioxide gas is a fast and effective sterilant, which could be used against a wide range of microorganisms like spores, bacteria and viruses. The exclusive physical properties of NO2 gas permit for sterilant dispersion in a clogged environment at room temperature and ambient pressure.
10. Boiling in water
Boiling a medical device in water for fifteen minutes will kill almost all vegetative bacteria and inactivate viruses, but boiling is ineffective against bacterial and fungal spores and prions, therefore boiling is unsuitable for sterilizing.
Flaming is usually done against loops and straight-wires in microbiology labs. Projecting the loop to the flame of a Bunsen burner or alcohol lamp till it glows red ascertains that any infectious agent gets inactivated. This is generally used for small glass or metal objects.
12. X-Ray Sterilization
This is a new and developing process of sterilization that is based on acquiring X-rays through conversion of electron beams. The X-rays formed have the same penetrating features as the rays formed by Cobalt-60. But this treatment is quicker, flexible, and more environmentally friendly.