Gaseous sterilent and plasma sterilization

various gas used for sterilization and new technology plasma sterilization

1. GASEOUS STERILIENT AND PLASMA STERILIZATION D r . JOICE . P . JIJI PERIO DEPT, VSDC

2. Gases used for Sterilization Formaldehyde Gas Ethylene Oxide Beta Propiolactone Ozone Chlorine Dioxide Nitrogen Oxide

3. FORMALDEHYDE GAS U sed in Operation Theater, Ward. Lab, Bedding, Furnitures etc. KMNO4 + FORMALIN Heating Formaldehyde Gas S terilization achieved by codensation of gas onexposed surface Broad Spectrum Biocidal Activity Gas is toxic and irritant Rooms should be sealed and left unopened for 48 hrs

4. Colorless liquid Boiling Point 10.7 Degree celsius Highly penetrating Gas Sweet Ethereal smell Effective against all micro organisms including Spores and Viruses Non corrosive ETHYLENE OXIDE

5. ETHYLENE OXIDE (contd) Used plastic and rubber articles, Respirator, Heart - Lung machines Sutures, Dental equipment and Clothing Highly explosive (more than 3% in air) Potential toxicity to Human Beings including Mutagenecity and Carcinogenecity Cycle takes more than 14 hrs Relatively high annual costs for maintenance and service

6. BETA PROPIOLACTONE This is a condensation product of Ketane and Formaldehyde Boiling point 168 Degree C Rapid action and Broad Spectrum activity More efficient than formaldehyde Also used for inactivation of vaccines Low Penetrating power and carcinogenic

7. OZONE Ozone is nothing more than three oxygen molecules electrically bound together, unlike stable oxygen you breathe, ozone has extremely greate oxidative power and very ready to react to germs, virus and a host of micro organism that are known to cause illness Today ozone sterilization is a hot topic for disinfection for food and water

8. OZONE (contd) Ozone is said to be 50% more powerful and acts 3000 times faster than Chlorine at 100 times the strength One advantage of an ozone system in food processing is that it provides the user an opportunity to re-use water It is cost effective and doesn’t leave any residue

9. OZONE (contd) Air based Water based 2 Types of Sterilizer Machines

10. CHLORINE DIOXIDE Commonly used to disinfect drinking water When used in small quantity, it is safe and doesnt lead to any health risks Higher dose can damage RBC’s and lining of GIT Toxic gas

11. NITROGEN DIOXIDE Nitrogen dioxide is a sterilant gas that is used in terminal sterilization of medical instruments. Bactericidal Advantages : Low sterilant concentration Rapid Microbial activity Operates at room temperature Rapidly penetrates since it is a gas and not a vapour. Minimal sterilant residual on processed articles Non carcinogenic, non inflammable, but toxic

12. NITROGEN DIOXIDE (contd) Polyurethane, nylon, polyacetal and some cellulose based papers are not compatible with nitrogen dioxide

13. Gas Plasma Sterilization Newer Technology Plasma 4th State of Matter Ionised gas consisting of positive ions and free electrons Vapourised hydrogen peroxide Low heat sterility cycle Now exclusively used by large manufacturers as the end line process for in house sterilization

14. Who found it ? 1879 Sir William Crookes - Founder 1928 Irving Langmuir coined the term as Plasma sterilization 1987 - Patented 1993 - US started marketing

15. Mechanism of action Free radicle interaction UV / Vaccum UV Radiation Volatization

16. Steps in Gas Plasma Sterilization 1 Vaccum Phase The chamber is evacuated, reducing internal pressure in preparation for subsequent reaction 2 Injection Phase Measured amount of liquid peroxide is injected into the chamber, evaporating the aqueous hydrogen peroxide solution and dispersing into the chamber where it kills the bacteria on any surface it can reach 3 Diffusion Phase The hydrogen peroxide permeates the chamber, exposing all load surfaces to the sterliant and rapidly sterilize devices and materials without leaving any toxic residue at the completion of this phase, chamber pressure is reduced and plasma discharge is initiated

17. Steps in Gas Plasma Sterilization 4 PLASMA Phase An electromagnetic field is created in which Hydrogen peroxide vapours break apart producing a low temperature plasma cloud that contains UV and free radicals. Following the reaction, the activated lose high energy and recombine to form oxygen and water 5 VENT Phase The chamber is vented to equalize the pressure enabling the chamber door to be opened. There is no need for aeration or cool down. Devices are ready for immediate use

18. Uses of Gas Plasma in Hospital Materials and devices that cannot tolerate high temperature and humidity such as plastics, electric device, corossion susceptible metal alloys can be sterilized Compatible with most medical devices and materials tested

19. Gas Plasma Sterilization Advantages Materials and device compatibility Rapid turn around time In house control of sterilization process Lower inventory requirement Safe, non toxic, dry, low temperature sterilization By products are water and oxygen Disadvantages Cannot be used on paper, cellulose or linen Small chamber Liquid, powder, strong absorbers and some lumen restriction It may corrode some materials

20. BIOLOPGICAL INDICATOR FOR QUALITY CONTROL BACILLUS ATROPHAEUS SPORES BACILLUS STEROTHERMOPHILIS

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