Sterilization2

 II) Chemical methods: are chemical compound used as sterile compounds.

·       It is Bactericidal but at low concentration is bacterostatic.

·       Properties 1. Not toxic for human.

                 2. Soluble

                 3. Stable

                 4. Detergent & penetration capacity

                 5. Non corrosiveness.

Examples:

         1.        Ethylene oxide:

• it is gas used for sterile plastic.

•has high penetration power.

•flammable & need long time.

         2.        Ozone:

•used for water, air & surface.

•Cause oxidation in organic substances.

•Unstable & toxic gas.

         3.        Bleach:

•Sterile liquid used in hospital & biological lab.

• Contain 5-25% sodium hypo chloride & stable at this concentration. Dilute before use.

•Kill Mycobacterium tuberculosis & remain on material 20min.

•It is corrosiveness.

         4.        Glutaraldehyde and formaldehyde:

•It is solution need 12hr. for killed microbes &spore.

•Low penetration.

•Toxic, volatile and expensive.

         5.        Hydrogen peroxide:

•Relative not toxic and should be dilute before use.

         6.        Ortho-phthaldehyde:

•Bactericidal.

•Stable &less volatile.

•Not irritant &pigment the skin (bind with protein).

• High penetration & expensive.

III) Radiation sterilization:

·       By used X ray, gamma ray and subatomic particles.

·       Gamma ray has high penetration & should be saving in radioisotope.

·       X ray is less penetration then need long time for expose.

·       U.V used for sterile surface and transparent material.